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Sample records for greater hydraulic pressure

  1. Energy harvesting from hydraulic pressure fluctuations

    International Nuclear Information System (INIS)

    Cunefare, K A; Skow, E A; Erturk, A; Savor, J; Verma, N; Cacan, M R

    2013-01-01

    State-of-the-art hydraulic hose and piping systems employ integral sensor nodes for structural health monitoring to avoid catastrophic failures. Energy harvesting in hydraulic systems could enable self-powered wireless sensor nodes for applications such as energy-autonomous structural health monitoring and prognosis. Hydraulic systems inherently have a high energy intensity associated with the mean pressure and flow. Accompanying the mean pressure is the dynamic pressure ripple, which is caused by the action of pumps and actuators. Pressure ripple is a deterministic source with a periodic time-domain behavior conducive to energy harvesting. An energy harvester prototype was designed for generating low-power electricity from pressure ripples. The prototype employed an axially-poled off-the-shelf piezoelectric stack. A housing isolated the stack from the hydraulic fluid while maintaining a mechanical coupling allowing for dynamic-pressure-induced deflection of the stack. The prototype exhibited an off-resonance energy harvesting problem since the fundamental resonance of the piezoelectric stack was much higher than the frequency content of the pressure ripple. The prototype was designed to provide a suitable power output for powering sensors with a maximum output of 1.2 mW. This work also presents electromechanical model simulations and experimental characterization of the piezoelectric power output from the pressure ripple in terms of the force transmitted into the harvester. (paper)

  2. Control rod driving hydraulic pressure device

    International Nuclear Information System (INIS)

    Ishida, Kazuo.

    1990-01-01

    Discharged water after actuating control rod drives in a BWR type reactor is once discharged to a discharging header, then returned to a master control unit and, subsequently, discharged to a reactor by way of a cooling water header. The radioactive level in the discharging header and the master control unit is increased by the reactor water to increase the operator's exposure. In view of the above, a riser is disposed for connecting a hydraulic pressure control unit incorporating a directional control valve and the cooling water head. When a certain control rod is inserted, the pressurized driving water is supplied through a hydraulic pressure control unit to the control rod drives. The discharged water from the control rod drives is entered by way of the hydraulic pressure control unit into the cooling water header and then returned to the reactor by way of other hydraulic pressure control unit and the control rod drives. Thus, the reactor water is no more recycled to the master control unit to reduce the radioactive exposure. (N.H.)

  3. Control rod driving hydraulic pressure device

    International Nuclear Information System (INIS)

    Ogawa, Masahide.

    1993-01-01

    The present invention concerns a control rod driving hydraulic device of a BWR type reactor, and provides an improvement for a means for supplying mechanical seal flashing water of a pump. That is, a mechanical seal flashing pipeline is branched at the downstream of a pressure-reducing orifice and connected to a minimum flow pipeline. With such a constitution, the minimum flow pipeline is connected to a minimum flow pipeline of an auxiliary pump at the downstream of the pressure-reducing orifice and returned to a suction pipeline of the pump. Pressure at the downstream of the pressure-reducing orifice is set, in the orifice, to a pressure required for mechanical seal flashing. Accordingly, the mechanical seal flashing pipeline is connected and a part of minimum flow rate is utilized, thereby enabling to cool mechanical seals. As a result, flow rate of the mechanical flashing water which has been flown out can be saved. The exhaustion amount from the pump can be reduced, to decrease the shaft power and reduce the capacity of the motor. (I.S.)

  4. Controlling a negative loaded hydraulic cylinder using pressure feedback

    DEFF Research Database (Denmark)

    Hansen, M.R.; Andersen, T.O.

    2010-01-01

    This paper is concerned with the inherent oscillatory nature of pressure compensated velocity control of a hydraulic cylinder subjected to a negative load and suspended by means of an over-center valve. Initially, a linearized stability analysis of such a hydraulic circuit is carried out clearly ...... in a nonlinear time domain simulation model validating the linear stability analysis....

  5. The hydraulics of the pressurized water reactors

    International Nuclear Information System (INIS)

    Bouchter, J.C.; Barbier, D.; Caruso, A.

    1999-01-01

    The SFEN organized, the 10 june 1999 at Paris, a meeting in the domain of the PWR hydraulics and in particular the hydraulic phenomena concerning the vessel and the vapor generators. The papers presented showed the importance of the industrial stakes with their associated phenomena: cores performance and safety with the more homogenous cooling system, the rods and the control rods wear, the temperature control, the fluid-structure interactions. A great part was also devoted to the progresses in the domain of the numerical simulation and the models and algorithms qualification. (A.L.B.)

  6. MODEL TESTING OF LOW PRESSURE HYDRAULIC TURBINE WITH HIGHER EFFICIENCY

    Directory of Open Access Journals (Sweden)

    V. K. Nedbalsky

    2007-01-01

    Full Text Available A design of low pressure turbine has been developed and it is covered by an invention patent and a useful model patent. Testing of the hydraulic turbine model has been carried out when it was installed on a vertical shaft. The efficiency was equal to 76–78 % that exceeds efficiency of the known low pressure blade turbines. 

  7. TRACKING CONTROL FOR A HYDRAULIC DRIVE WITH A PRESSURE COMPENSATOR

    Directory of Open Access Journals (Sweden)

    S. V. Aranovskiy

    2015-07-01

    Full Text Available A problem of tracking control is considered for a hydraulic drive with a pressure compensator that is widespread in the equipment of heavy-duty machines. Method. The control problem is solved by means of a switching sliding-mode controller coupled with static nonlinear compensation and desired velocity feedforward. Main Results. Mathematical model of a hydraulic drive is given in view of the pressure compensator presence. Traditional model of a hydraulic drive is formulated for a system with a spool valve; purpose and principles of operation of the pressure compensator in hydraulic systems are described, and the extended model is presented illustrating compensator contribution to overall system dynamics. It is shown that the obtained model has an input static nonlinearity; the nonlinearity cancellation method is proposed giving the possibility for injection of a desired velocity feedforward term. The control law is chosen as a switching one and two chattering attenuation methods are studied: equivalent control estimation via filtering and sign function integration. Experimental studies are performed at a forestry hydraulic crane prototype and illustrate high tracking accuracy achieved for typical crane motions. Practical Significance. The results are suitable for heavy-duty hydraulic machines automation in construction, road building and forestry.

  8. Pressure control of hydraulic servo system using proportional control valve

    International Nuclear Information System (INIS)

    Yang, Kyong Uk; Oh, In Ho; Lee, Ill Yeong

    1999-01-01

    The purpose of this study is to develop a control scheme for the hydraulic servo system which can rapidly control the pressure in a hydraulic cylinder with very short stroke. Compared with the negligible stroke of the cylinder in the system, the flow gain of the proportional pressure control valve constituting the hydraulic servo system is relatively large and the time delay on the response of the valve is quite long. Therefore, the pressure control system, in this study tends to get unstable during operations. Considering the above mentioned characteristics of the system, a two-degree-of-freedom control scheme, composed of the I-PDD 2 ... feedback compensator and the feedforward controller, is proposed. The reference model scheme is used in deciding the parameters of the controllers. The validity of the proposed control scheme is confirmed through the experiments

  9. Thermal Hydraulic Integral Effect Tests for Pressurized Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Baek, W. P.; Song, C. H.; Kim, Y. S. and others

    2005-02-15

    The objectives of the project are to construct a thermal-hydraulic integral effect test facility and to perform various integral effect tests for design, operation, and safety regulation of pressurized water reactors. During the first phase of this project (1997.8{approx}2002.3), the basic technology for thermal-hydraulic integral effect tests was established and the basic design of the test facility was accomplished: a full-height, 1/300-volume-scaled full pressure facility for APR1400, an evolutionary pressurized water reactor that was developed by Korean industry. Main objectives of the present phase (2002.4{approx}2005.2), was to optimize the facility design and to construct the experimental facility. We have performed following researches: 1) Optimization of the basic design of the thermal-hydraulic integral effect test facility for PWRs - ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation) - Reduced height design for APR1400 (+ specific design features of KSNP safety injection systems) - Thermal-hydraulic scaling based on three-level scaling methodology by Ishii et al. 2) Construction of the ATLAS facility - Detailed design of the test facility - Manufacturing and procurement of components - Installation of the facility 3) Development of supporting technology for integral effect tests - Development and application of advanced instrumentation technology - Preliminary analysis of test scenarios - Development of experimental procedures - Establishment and implementation of QA system/procedure.

  10. Hydraulic pressure control unit for control rod drive

    International Nuclear Information System (INIS)

    Watabe, Yukio.

    1990-01-01

    The pressure invention concerns a hydraulic pressure control unit for control rod drives in BWR type reactors. The space above a floating piston possessed by an accumulator and the housing of control rod drives are connected by means of a pipeline. The pipeline has a scram valve which is opened upon occurrence of reactor scram. A pump is disposed between the accumulator and the scram valve for communicating a discharge port to apply a high pressure water to the accumulator. According to the present invention, a control unit is disposed between the scram valve and the housing of the control rod drives in the hydraulic pressure control unit for maintaining the cross sectional area of the flow channel of the pipeline to a usual size when the pressure in a pressure vessel is under a rated operation pressure, while limiting the cross sectional area of the flow channel when the pressure is lower than that in the rated operation. Thus, whole insertion of the control rod substantially at a constant speed is enabled irrespective of the level of the pressure in the pressure vessel. (I.S.)

  11. Simulation of Thermal Hydraulic at Supercritical Pressures with APROS

    Energy Technology Data Exchange (ETDEWEB)

    Kurki, Joona [VTT Technical Research Centre of Finland, P.O. Box 1000, FI02044 VTT (Finland)

    2008-07-01

    The proposed concepts for the fourth generation of nuclear reactors include a reactor operating with water at thermodynamically supercritical state, the Supercritical Water Reactor (SCWR). For the design and safety demonstrations of such a reactor, the possibility to accurately simulate the thermal hydraulics of the supercritical coolant is an absolute prerequisite. For this purpose, the one-dimensional two-phase thermal hydraulics solution of APROS process simulation software was developed to function at the supercritical pressure region. Software modifications included the redefinition of some parameters that have physical significance only at the subcritical pressures, improvement of the steam tables, and addition of heat transfer and friction correlations suitable for the supercritical pressure region. (author)

  12. Thermal Hydraulic Integral Effect Tests for Pressurized Water Reactors

    International Nuclear Information System (INIS)

    Baek, Won Pil; Song, C. H.; Kim, Y. S.

    2007-02-01

    The objectives of the project are to construct a thermal-hydraulic integral effect test facility and to perform the tests for design, operation, and safety regulation of pressurized water reactors. In the first phase of this project (1997.8∼2002.3), the basic technology for thermal-hydraulic integral effect tests was established and the basic design of the test facility was accomplished. In the second phase (2002.4∼2005.2), an optimized design of the ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation) was established and the construction of the facility was almost completed. In the third phase (2005.3∼2007.2), the construction and commission tests of the ATLAS are to be completed and some first-phase tests are to be conducted

  13. Analysis of and H∞ Controller Design For An Electro-Hydraulic Servo Pressure Regulator

    DEFF Research Database (Denmark)

    Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole

    2011-01-01

    -circuit pumps are still hydraulically controlled, there is however still a need for being able to generate a hydraulic pilot pressure. The focus of the current paper is on the analysis and controller design of an electrohydraulic servo pressure regulator, which generates a hydraulic LS-pressure for a variable...

  14. Pressure Transient Model of Water-Hydraulic Pipelines with Cavitation

    Directory of Open Access Journals (Sweden)

    Dan Jiang

    2018-03-01

    Full Text Available Transient pressure investigation of water-hydraulic pipelines is a challenge in the fluid transmission field, since the flow continuity equation and momentum equation are partial differential, and the vaporous cavitation has high dynamics; the frictional force caused by fluid viscosity is especially uncertain. In this study, due to the different transient pressure dynamics in upstream and downstream pipelines, the finite difference method (FDM is adopted to handle pressure transients with and without cavitation, as well as steady friction and frequency-dependent unsteady friction. Different from the traditional method of characteristics (MOC, the FDM is advantageous in terms of the simple and convenient computation. Furthermore, the mechanism of cavitation growth and collapse are captured both upstream and downstream of the water-hydraulic pipeline, i.e., the cavitation start time, the end time, the duration, the maximum volume, and the corresponding time points. By referring to the experimental results of two previous works, the comparative simulation results of two computation methods are verified in experimental water-hydraulic pipelines, which indicates that the finite difference method shows better data consistency than the MOC.

  15. Changes in entrapped gas content and hydraulic conductivity with pressure.

    Science.gov (United States)

    Marinas, Maricris; Roy, James W; Smith, James E

    2013-01-01

    Water table fluctuations continuously introduce entrapped air bubbles into the otherwise saturated capillary fringe and groundwater zone, which reduces the effective (quasi-saturated) hydraulic conductivity, K(quasi), thus impacting groundwater flow, aquifer recharge and solute and contaminant transport. These entrapped gases will be susceptible to compression or expansion with changes in water pressure, as would be expected with water table (and barometric pressure) fluctuations. Here we undertake laboratory experiments using sand-packed columns to quantify the effect of water table changes of up to 250 cm on the entrapped gas content and the quasi-saturated hydraulic conductivity, and discuss our ability to account for these mechanisms in ground water models. Initial entrapped air contents ranged between 0.080 and 0.158, with a corresponding K(quasi) ranging between 2 and 6 times lower compared to the K(s) value. The application of 250 cm of water pressure caused an 18% to 26% reduction in the entrapped air content, resulting in an increase in K(quasi) by 1.16 to 1.57 times compared to its initial (0 cm water pressure) value. The change in entrapped air content measured at pressure step intervals of 50 cm, was essentially linear, and could be modeled according to the ideal gas law. Meanwhile, the changes in K(quasi) with compression-expansion of the bubbles because of pressure changes could be adequately captured with several current hydraulic conductivity models. © Ground Water 2012 and © Her Majesty the Queen in Right of Canada 2012. Ground Water © 2012, National Ground Water Association.

  16. Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

    Science.gov (United States)

    Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

    2016-01-01

    A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

  17. Hydraulic testing in granite using the sinusoidal variation of pressure

    International Nuclear Information System (INIS)

    Black, J.H.; Holmes, D.C.; Noy, D.J.

    1982-09-01

    Access to two boreholes at the Carwynnen test site in Cornwall enabled the trial of a number of innovative approaches to the hydrogeology of fractured crystalline rock. These methods ranged from the use of seisviewer data to measure the orientation of fractures to the use of the sinusoidal pressure technique to measure directional hydraulic diffusivity. The testing began with a short programme of site investigation consisting of borehole caliper and seisviewer logging followed by some single borehole hydraulic tests. The single borehole hydraulic testing was designed to assess whether the available boreholes and adjacent rock were suitable for testing using the sinusoidal method. The main testing methods were slug and pulse tests and were analysed using the fissured porous medium analysis proposed in Barker and Black (1983). Derived hydraulic conductivity (K) ranged from 2 x 10 -12 m/sec to 5 x 10 -7 m/sec with one near-surface zone of high K being perceived in both boreholes. The results were of the form which is typical of fractured rock and indicated a combination of high fracture frequency and permeable granite matrix. The results are described and discussed. (author)

  18. Effect of Hydraulic Pressure on Warm Hydro Mechanical Deep Drawing of Magnesium Alloy Sheet

    Science.gov (United States)

    Liu, Wei; Wu, Linzhi; Yuan, Shijian

    The uniaxial tensile test and hydraulic bulging test of AZ31 magnesium alloy sheets were applied to study the influence of temperature on the material properties and obtain the forming limit curves at different temperatures. Numerical simulations of warm hydro mechanical deep drawing were carried out to investigate the effect of hydraulic pressure on the formability of a cylindrical cup, and the simplified hydraulic pressure profiles were used to simulate the loading procedure of hydraulic pressure. The optimal hydraulic pressure at different temperatures were given and verified by experimental studies at temperature 100°C and 170V.

  19. Thermal hydraulic behavior of SCWR sliding pressure startup

    International Nuclear Information System (INIS)

    Fu Shengwei; Zhou Chong; Xu Zhihong; Yang Yanhua

    2011-01-01

    The modification to ATHLET-SC code is introduced in this paper, which realizes the simulation of trans-critical transients using two-phase model. With the modified code, the thermal-hydraulic dynamic behavior of the mixed SCWR core during the startup process is simulated. The startup process is similar to the design of SCLWR-H sliding pressure startup. The results show that maximum temperature of cladding-surface does not exceed 650℃ in the whole startup process, and the sudden change of water properties in the trans-critical transients will not cause harmful influence to the heat transfer of the fuel cladding. (authors)

  20. Study of pore pressure reaction on hydraulic fracturing

    Science.gov (United States)

    Trimonova, Mariia; Baryshnikov, Nikolay; Turuntaev, Sergey; Zenchenko, Evgeniy; Zenchenko, Petr

    2017-04-01

    We represent the results of the experimental study of the hydraulic fracture propagation influence on the fluid pore pressure. Initial pore pressure was induced by injection and production wells. The experiments were carried out according to scaling analysis based on the radial model of the fracture. All required geomechanical and hydrodynamical properties of a sample were derived from the scaling laws. So, gypsum was chosen as a sample material and vacuum oil as a fracturing fluid. The laboratory setup allows us to investigate the samples of cylindrical shape. It can be considered as an advantage in comparison with standard cubic samples, because we shouldn't consider the stress field inhomogeneity induced by the corners. Moreover, we can set 3D-loading by this setting. Also the sample diameter is big enough (43cm) for placing several wells: the fracturing well in the center and injection and production wells on two opposite sides of the central well. The experiment consisted of several stages: a) applying the horizontal pressure; b) applying the vertical pressure; c) water solution injection in the injection well with a constant pressure; d) the steady state obtaining; e) the oil injection in the central well with a constant rate. The pore pressure was recorded in the 15 points along bottom side of the sample during the whole experiment. We observe the pore pressure change during all the time of the experiment. First, the pore pressure changed due to water injection. Then we began to inject oil in the central well. We compared the obtained experimental data on the pore pressure changes with the solution of the 2D single-phase equation of pore-elasticity, and we found significant difference. The variation of the equation parameters couldn't help to resolve the discrepancy. After the experiment, we found that oil penetrated into the sample before and after the fracture initiation. This fact encouraged us to consider another physical process - the oil

  1. Analysis of an controller design for an electro-hydraulic servo pressure regulator

    DEFF Research Database (Denmark)

    Pedersen, Henrik C.; Andersen, Torben Ole; Madsen, A. M.

    2009-01-01

    Mobile hydraulics is in a transition phase, where electronic sensors and digital signal processors are starting to become standard on a high number of machines, hereby replacing hydraulic pilot lines and oering new possibilities with regard to both control and feasibility. For controlling some...... of the existing hydraulic components there are, however, still a need for being able to generate a hydraulic pilot pressure, as e.g. almost all open-circuit pumps are hydraulically controlled. The focus of the current paper is therefore on the analysis and controller design an electro-hydraulic servo pressure...... regulator, which generates a hydraulic LS-pressure based on an electrical reference, hereby synergistically integrating knowledge from all parts of the mechatronics area. The servo pressure regulator is used to generate the LS-signal for a variable displacement pump, and the paper rst presents...

  2. Study on acoustic emission signals of active defect in pressure piping under hydraulic pressure

    International Nuclear Information System (INIS)

    Ai Qiong; Liu Caixue; Wang Yao; He Pan; Song Jian

    2009-01-01

    Experimental investigations of acoustic emission (AE) of active defect in pressure piping with a prefabricated crack under hydraulic pressure tester were conducted. AE signals of fatigue-crack-growth in pressure piping were monitored incessantly in all processes, and all signals recorded were analyzed and processed. The result of signal processing show that the amplitude and energy of acoustic emission signals from defect in pressure pipeline increase gradually with the load time, and thus the active defects in pipeline can be identified; the amplitude, energy and count of acoustic emission signals increase sharply before the defect runs through, and we can forecast the penetrated leakage of pipeline. (authors)

  3. Geothermal heat from solid rock - increased energy extraction through hydraulic pressurizing of drill wells

    International Nuclear Information System (INIS)

    Ramstad, Randi Kalskin; Hilmo, Bernt Olav; Skarphagen, Helge

    2005-01-01

    New equipment for hydraulic pressurizing, a double collar of the type FrakPak - AIP 410-550, is developed by the Broennteknologi AS. The equipment is tested in the laboratory and in the field at Lade in Trondheim. By the construction of two pilot plants for geothermal heat at Bryn and on the previous grounds of the energy company in Asker and Baerum (EAB) extensive studies connected to hydraulic pressurizing are carried out both with water and sand injection. The geothermal heat plants at Bryn and AEB were supposed to be based on pumped ground water from rock wells where increased effect was obtained through pumping up, returning and circulating the water. The aim of the study was to test and develop the methods for hydraulic pressurizing both with water and sand injection, document the effect of the various types of pressurizing as well as mapping the hydro- and rock geological conditions for this type of geothermal heat plants. In addition to stimulating 10 drill holes with hydraulic pressurizing with water and sand injection, the studies have carried out test pumping, water sampling, geophysical logging, measurements of alterations in the terrain, current and rock strain measurements and geothermal response tests. Furthermore an efficacy test and a theoretical model of the energy potential of the plants are carried out. The results from the pilot plant at Bryn show that the drill hole capacities are significantly increased both through hydraulic pressurizing with water and sand injection. There seems to be a greater need for sand as ''prepping agent'' or distance maker in cracks with high pressure resistance than in cracks with lower resistance. The grain size of the sand should be adapted to the resistance pressure and injection of coarser sand is recommended in cracks with lower resistance pressure. The rock strength and strain conditions determine the successes of hydraulic pressurizing at the reopening of existing or opening of new faults. Test pumping was

  4. Failure Mode of the Water-filled Fractures under Hydraulic Pressure in Karst Tunnels

    Directory of Open Access Journals (Sweden)

    Dong Xin

    2017-06-01

    Full Text Available Water-filled fractures continue to grow after the excavation of karst tunnels, and the hydraulic pressure in these fractures changes along with such growth. This paper simplifies the fractures in the surrounding rock as flat ellipses and then identifies the critical hydraulic pressure values required for the occurrence of tensile-shear and compression-shear failures in water-filled fractures in the case of plane stress. The occurrence of tensile-shear fracture requires a larger critical hydraulic pressure than compression-shear failure in the same fracture. This paper examines the effects of fracture strike and lateral pressure coefficient on critical hydraulic pressure, and identifies compression-shear failure as the main failure mode of water-filled fractures. This paper also analyses the hydraulic pressure distribution in fractures with different extensions, and reveals that hydraulic pressure decreases along with the continuous growth of fractures and cannot completely fill a newly formed fracture with water. Fracture growth may be interrupted under the effect of hydraulic tensile shear.

  5. Response time verification of in situ hydraulic pressure sensors in a nuclear reactor

    International Nuclear Information System (INIS)

    Foster, C.G.

    1978-01-01

    A method and apparatus for verifying response time in situ of hydraulic pressure and pressure differential sensing instrumentation in a nuclear circuit is disclosed. Hydraulic pressure at a reference sensor and at an in situ process sensor under test is varied according to a linear ramp. Sensor response time is then determined by comparison of the sensor electrical analog output signals. The process sensor is subjected to a relatively slowly changing and a relatively rapidly changing hydraulic pressure ramp signal to determine an upper bound for process sensor response time over the range of all pressure transients to which the sensor is required to respond. Signal linearity is independent of the volumetric displacement of the process sensor. The hydraulic signal generator includes a first pressurizable gas reservoir, a second pressurizable liquid and gas reservoir, a gate for rapidly opening a gas communication path between the two reservoirs, a throttle valve for regulating rate of gas pressure equalization between the two reservoirs, and hydraulic conduit means for simultaneously communicating a ramp of hydraulic pressure change between the liquid/gas reservoir and both a reference and a process sensor. By maintaining a sufficient pressure differential between the reservoirs and by maintaining a sufficient ratio of gas to liquid in the liquid/gas reservoir, excellent linearity and minimal transient effects can be achieved for all pressure ranges, magnitudes, and rates of change of interest

  6. Experimental study of the pressure discharge process for the hydraulic control rod drive system stepped cylinder

    International Nuclear Information System (INIS)

    Wang, Jinhua; Bo, Hanliang; Zheng, Wenxiang

    2002-01-01

    The pressure discharge process from the stepped cylinder of the Hydraulic Control Rod Drive System (HCRDS) was studied experimentally in the HCRDS experimental loop for the 200 MW Nuclear Heating Reactor (NHR-200). The results showed that the differential pressure between the outside and the inside of the stepped cylinder increased rapidly to the desired value so that the force induced by the differential pressure which pushes the out tube of stepped cylinder was large enough. Therefore, if the hydraulic control rod were jammed, the pressure could push the hydraulic control rod to overcome the frictional resistance to insert the control rod into the reactor core. The experimental results verified that this design would solve the problem of hydraulic control rod jamming during an accident. (author)

  7. Thermal-Hydraulics analysis of pressurized water reactor core by using single heated channel model

    Directory of Open Access Journals (Sweden)

    Reza Akbari

    2017-08-01

    Full Text Available Thermal hydraulics of nuclear reactor as a basis of reactor safety has a very important role in reactor design and control. The thermal-hydraulic analysis provides input data to the reactor-physics analysis, whereas the latter gives information about the distribution of heat sources, which is needed to perform the thermal-hydraulic analysis. In this study single heated channel model as a very fast model for predicting thermal hydraulics behavior of pressurized water reactor core has been developed. For verifying the results of this model, we used RELAP5 code as US nuclear regulatory approved thermal hydraulics code. The results of developed single heated channel model have been checked with RELAP5 results for WWER-1000. This comparison shows the capability of single heated channel model for predicting thermal hydraulics behavior of reactor core.

  8. Interstitial hydraulic conductivity and interstitial fluid pressure for avascular or poorly vascularized tumors.

    Science.gov (United States)

    Liu, L J; Schlesinger, M

    2015-09-07

    A correct description of the hydraulic conductivity is essential for determining the actual tumor interstitial fluid pressure (TIFP) distribution. Traditionally, it has been assumed that the hydraulic conductivities both in a tumor and normal tissue are constant, and that a tumor has a much larger interstitial hydraulic conductivity than normal tissue. The abrupt transition of the hydraulic conductivity at the tumor surface leads to non-physical results (the hydraulic conductivity and the slope of the TIFP are not continuous at tumor surface). For the sake of simplicity and the need to represent reality, we focus our analysis on avascular or poorly vascularized tumors, which have a necrosis that is mostly in the center and vascularization that is mostly on the periphery. We suggest that there is an intermediary region between the tumor surface and normal tissue. Through this region, the interstitium (including the structure and composition of solid components and interstitial fluid) transitions from tumor to normal tissue. This process also causes the hydraulic conductivity to do the same. We introduce a continuous variation of the hydraulic conductivity, and show that the interstitial hydraulic conductivity in the intermediary region should be monotonically increasing up to the value of hydraulic conductivity in the normal tissue in order for the model to correspond to the actual TIFP distribution. The value of the hydraulic conductivity at the tumor surface should be the lowest in value. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Pressure variation characteristics at trapping region in oil hydraulic piston pumps

    International Nuclear Information System (INIS)

    Kim, Jong Ki; Jung, Jae Youn; Rho, Byung Joon; Song, Kyu Keun; Oh, Seok Hyung

    2003-01-01

    Pressure variation is one of the major sources on noise emission in the oil hydraulic piston pumps. Therefore, it is necessary to clarify about pressure variation characteristics of the oil hydraulic piston pumps to reduce noise. Pressure variations in a cylinder at trapping region were measured during pump working period with discharge pressures, rotational speeds. The effect of pre-compression of the discharge port with three types valve plates also investigated. It was found that the pressure variation characteristics of oil hydraulic piston pumps deeply related with pre-compression design of the discharge port. Also, it was found that the pressure overshoot at trapping region can reduce by use of pre-compression at the end of the discharge port in valve plate

  10. Tree shoot bending generates hydraulic pressure pulses: a new long-distance signal?

    Science.gov (United States)

    Lopez, Rosana; Badel, Eric; Peraudeau, Sebastien; Leblanc-Fournier, Nathalie; Beaujard, François; Julien, Jean-Louis; Cochard, Hervé; Moulia, Bruno

    2014-05-01

    When tree stems are mechanically stimulated, a rapid long-distance signal is induced that slows down primary growth. An investigation was carried out to determine whether the signal might be borne by a mechanically induced pressure pulse in the xylem. Coupling xylem flow meters and pressure sensors with a mechanical testing device, the hydraulic effects of mechanical deformation of tree stem and branches were measured. Organs of several tree species were studied, including gymnosperms and angiosperms with different wood densities and anatomies. Bending had a negligible effect on xylem conductivity, even when deformations were sustained or were larger than would be encountered in nature. It was found that bending caused transient variation in the hydraulic pressure within the xylem of branch segments. This local transient increase in pressure in the xylem was rapidly propagated along the vascular system in planta to the upper and lower regions of the stem. It was shown that this hydraulic pulse originates from the apoplast. Water that was mobilized in the hydraulic pulses came from the saturated porous material of the conduits and their walls, suggesting that the poroelastic behaviour of xylem might be a key factor. Although likely to be a generic mechanical response, quantitative differences in the hydraulic pulse were found in different species, possibly related to differences in xylem anatomy. Importantly the hydraulic pulse was proportional to the strained volume, similar to known thigmomorphogenetic responses. It is hypothesized that the hydraulic pulse may be the signal that rapidly transmits mechanobiological information to leaves, roots, and apices.

  11. Discussion on Stochastic Analysis of Hydraulic Vibration in Pressurized Water Diversion and Hydropower Systems

    Directory of Open Access Journals (Sweden)

    Jianxu Zhou

    2018-03-01

    Full Text Available Hydraulic vibration exists in various water conveyance projects and has resulted in different operating problems, but its obvious effects on system’s pressure head and stable operation have not been definitively addressed in the issued codes for engineering design, especially considering the uncertainties of hydraulic vibration. After detailed analysis of the randomness in hydraulic vibration and the commonly used stochastic approaches, in the basic equations for hydraulic vibration analysis, the random parameters and the formed stochastic equations were discussed for further probabilistic characteristic analysis of the random variables. Furthermore, preliminary investigation of the stochastic analysis of hydraulic vibration in pressurized pipelines and possible self-excited vibration in pumped-storage systems was presented for further consideration. The detailed discussion indicates that it is necessary to conduct further and systematic stochastic analysis of hydraulic vibration. Further, with the obtained frequencies and amplitudes in the form of a probability statement, the stochastic characteristics of various hydraulic vibrations can be investigated in detail and these solutions will be more reasonable for practical applications. Eventually, the stochastic analysis of hydraulic vibration will provide a basic premise to introduce its effect into the engineering design of water diversion and hydropower systems.

  12. Development of Proportional Pressure Control Valve for Hydraulic Braking Actuator of Automobile ABS

    Directory of Open Access Journals (Sweden)

    Che-Pin Chen

    2018-04-01

    Full Text Available This research developed a novel proportional pressure control valve for an automobile hydraulic braking actuator. It also analyzed and simulated solenoid force of the control valves, and the pressure relief capability test of electromagnetic thrust with the proportional valve body. Considering the high controllability and ease of production, the driver of this proportional valve was designed with a small volume and powerful solenoid force to control braking pressure and flow. Since the proportional valve can have closed-loop control, the proportional valve can replace a conventional solenoid valve in current brake actuators. With the proportional valve controlling braking and pressure relief mode, it can narrow the space of hydraulic braking actuator, and precisely control braking force to achieve safety objectives. Finally, the proposed novel proportional pressure control valve of an automobile hydraulic braking actuator was implemented and verified experimentally.

  13. Measuring the initial earth pressure of granite using hydraulic fracturing test; Goseong and Yuseong areas

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Won, Kyung Sik [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-02-01

    This report provides the initial earth pressure of granitic rocks obtained from Deep Core Drilling Program which is carried out as part of the assessment of deep geological environmental condition. These data are obtained by hydraulic fracturing test in three boreholes drilled up to 350{approx}500 m depth at the Yuseong and Goseong sites. These sites were selected based on the result of preliminary site evaluation study. The boreholes are NX-size (76 mm) and vertical. The procedure of hydraulic fracturing test is as follows: - Selecting the testing positions by preliminary investigation using BHTV logging. - Performing the hydraulic fracturing test at each selected position with depth.- Estimating the shut-in pressure by the bilinear pressure-decay-rate method. - Estimating the fracture reopening pressure from the pressure-time curves.- Estimating the horizontal principal stresses and the direction of principal stresses. 65 refs., 39 figs., 12 tabs. (Author)

  14. Strain measurement in and analysis for hydraulic test of CPR1000 reactor pressure vessel

    International Nuclear Information System (INIS)

    Zhou Dan; Zhuang Dongzhen

    2013-01-01

    The strain measurement in hydraulic test of CPR1000 reactor pressure vessel performed in Dongfang Heavy Machinery Co., Ltd. is introduced. The detail test scheme and method was introduced and the measurement results of strain and stress was given. Meanwhile the finite element analysis was performed for the pressure vessel, which was generally matched with the measurement results. The reliability of strain measurement was verified and the high strength margin of vessel was shown, which would give a good reference value for the follow-up hydraulic tests and strength analysis of reactor pressure vessel. (authors)

  15. Thermal-hydraulics of the Loviisa reactor pressure vessel overcooling transients

    International Nuclear Information System (INIS)

    Tuomisto, Harri.

    1987-06-01

    In the Loviisa reactor pressure vessel safety analyses, the thermal-hydraulics of various overcooling transients has been evaluated to give pertinent initial data for fracture-mechanics calculations. The thermal-hydraulic simulations of the developed overcooling scenarios have been performed using best-estimate thermal-hydraulic computer codes. Experimental programs have been carried out to study phenomena related to natural circulation interruptions in the reactor coolant system. These experiments include buoyancy-induced phenomena such as thermal mixing and stratification of cold high-pressure safety injection water in the cold legs and the downcomer, and oscillations of the single-phase natural circulation. In the probabilistic pressurized thermal shock study, the Loviisa training simulator and the advanced system code RELAP5/MOD2 were utilized to simulate selected sequences. Flow stagnation cases were separately calculated with the REMIX computer program. The methods employed were assessed for these calculations against the plant data and own experiments

  16. Micro-hydromechanical deep drawing of metal cups with hydraulic pressure effects

    Science.gov (United States)

    Luo, Liang; Jiang, Zhengyi; Wei, Dongbin; Wang, Xiaogang; Zhou, Cunlong; Huang, Qingxue

    2018-03-01

    Micro-metal products have recently enjoyed high demand. In addition, metal microforming has drawn increasing attention due to its net-forming capability, batch manufacturing potential, high product quality, and relatively low equipment cost. Micro-hydromechanical deep drawing (MHDD), a typical microforming method, has been developed to take advantage of hydraulic force. With reduced dimensions, the hydraulic pressure development changes; accordingly, the lubrication condition changes from the macroscale to the microscale. A Voronoi-based finite element model is proposed in this paper to consider the change in lubrication in MHDD according to open and closed lubricant pocket theory. Simulation results agree with experimental results concerning drawing force. Changes in friction significantly affect the drawing process and the drawn cups. Moreover, defined wrinkle indexes have been shown to have a complex relationship with hydraulic pressure. High hydraulic pressure can increase the maximum drawing ratio (drawn cup height), whereas the surface finish represented by the wear is not linearly dependent on the hydraulic pressure due to the wrinkles.

  17. Thermal hydraulic stability in a pressure tube nuclear reactor

    International Nuclear Information System (INIS)

    Villani, A.; Ravetta, R.; Mansani, L.

    1986-01-01

    The CIRENE plant which will undergo preoperational tests in the near future is equipped with a 40 MW(e) Heavy Water moderated Boiling Light Water cooled Reactor (HWBLWR); at the start-up and up to about 30 % of nominal power, the necessary low coolant density is obtained injecting into the core a mixture of liquid and steam. To verify the thermal-hydraulic stability of the plant in this situation, tests have been carried out in a facility simulating two full scale power channels; the system stability has been confirmed in the reference conditions, and is not reduced by even a significant reduction of the liquid flowrate, where a decrease in liquid temperature has some negative effect and steam flowrate has a small influence. (author)

  18. Characterizing hydraulic fractures in shale gas reservoirs using transient pressure tests

    Directory of Open Access Journals (Sweden)

    Cong Wang

    2015-06-01

    This work presents an unconventional gas reservoir simulator and its application to quantify hydraulic fractures in shale gas reservoirs using transient pressure data. The numerical model incorporates most known physical processes for gas production from unconventional reservoirs, including two-phase flow of liquid and gas, Klinkenberg effect, non-Darcy flow, and nonlinear adsorption. In addition, the model is able to handle various types and scales of fractures or heterogeneity using continuum, discrete or hybrid modeling approaches under different well production conditions of varying rate or pressure. Our modeling studies indicate that the most sensitive parameter of hydraulic fractures to early transient gas flow through extremely low permeability rock is actually the fracture-matrix contacting area, generated by fracturing stimulation. Based on this observation, it is possible to use transient pressure testing data to estimate the area of fractures generated from fracturing operations. We will conduct a series of modeling studies and present a methodology using typical transient pressure responses, simulated by the numerical model, to estimate fracture areas created or to quantity hydraulic fractures with traditional well testing technology. The type curves of pressure transients from this study can be used to quantify hydraulic fractures in field application.

  19. The oil pressure test of the hydraulic impeller blade

    Science.gov (United States)

    Ye, Wen-bo; Jia, Li-tao

    2017-12-01

    This article introduced the structure of the Kaplan runner in hydropower station and the operating process of the oil pressure test has been described. What’s more, the whole process, including filling oil to the runner hub, the movement of the runner blade, the oil circuit, have been presented in detail.Since the manipulation of the oil circuit which controlled by three Valve groups consisting of six valves was complicated, the author is planning to replace them with 3-position 3-way electromagnetic valves, so we can simplify the operation procedure.The author hopes this article can provide technical reference for the oil pressure test.

  20. Maxillary sinus floor elevation via crestal approach: the evolution of the hydraulic pressure technique.

    Science.gov (United States)

    Lopez, Michele Antonio; Andreasi Bassi, Mirko; Confalone, Luca; Carinci, Francesco

    2014-01-01

    The current study describes an innovative protocol for the surgical maxillary sinus augmentation via a crestal approach that uses hydraulic pressure to lift the Schneiderian membrane and simultaneously fill the subantral space with a biomaterial for bone regeneration (nanocrystalline hydroxyapatite in aqueous solution). The technique in question combines the advantages of large amounts of grafted biomaterial with reduced trauma, high precision, and predictability.

  1. Averaging hydraulic head, pressure head, and gravitational head in subsurface hydrology, and implications for averaged fluxes, and hydraulic conductivity

    Directory of Open Access Journals (Sweden)

    G. H. de Rooij

    2009-07-01

    Full Text Available Current theories for water flow in porous media are valid for scales much smaller than those at which problem of public interest manifest themselves. This provides a drive for upscaled flow equations with their associated upscaled parameters. Upscaling is often achieved through volume averaging, but the solution to the resulting closure problem imposes severe restrictions to the flow conditions that limit the practical applicability. Here, the derivation of a closed expression of the effective hydraulic conductivity is forfeited to circumvent the closure problem. Thus, more limited but practical results can be derived. At the Representative Elementary Volume scale and larger scales, the gravitational potential and fluid pressure are treated as additive potentials. The necessary requirement that the superposition be maintained across scales is combined with conservation of energy during volume integration to establish consistent upscaling equations for the various heads. The power of these upscaling equations is demonstrated by the derivation of upscaled water content-matric head relationships and the resolution of an apparent paradox reported in the literature that is shown to have arisen from a violation of the superposition principle. Applying the upscaling procedure to Darcy's Law leads to the general definition of an upscaled hydraulic conductivity. By examining this definition in detail for porous media with different degrees of heterogeneity, a series of criteria is derived that must be satisfied for Darcy's Law to remain valid at a larger scale.

  2. Moderate Versus Light Pressure Massage Therapy Leads to Greater Weight Gain in Preterm Infants

    Science.gov (United States)

    Field, Tiffany; Diego, Miguel A.; Hernandez-Reif, Maria; Deeds, Osvelia; Figuereido, Barbara

    2007-01-01

    Sixty-eight preterm infants (M GA=3Owks.) were randomly assigned to a moderate or to a light pressure massage therapy group to receive 15 massages 3 times per day for 5 days. Behavior state, stress behaviors and heart rate were recorded for 15 minutes before and during the first 15-minute therapy session. Weight gain was recorded over the 5 day therapy period. The moderate versus light pressure massage group gained significantly more weight per day. During the behavior observations the moderate versus light pressure massage group showed significantly lower increases from the pre-session to the session recording on: 1) active sleep; 2) fussing; 3) crying; 4) movement; and 5) stress behavior (hiccupping). They also showed a smaller decrease in deep sleep, a greater decrease in heart rate and a greater increase in vagal tone. Thus, the moderate pressure massage therapy group appeared to be more relaxed and less aroused than the light pressure massage group which may have contributed to the greater weight gain of the moderate pressure massage therapy group. PMID:17138310

  3. Effect of Hydraulic Accumulator on Pressure Surge of a Hydrostatic Transmission System

    Science.gov (United States)

    Kumar, Ajit; Das, Jayanta; Dasgupta, Kabir; Barnwal, Manish Kumar

    2018-04-01

    Hydraulic power system is generally used in off-road vehicles for power transmission such as Heavy Earth Moving Machineries (HEMM). Their energy efficiency and unsubstantial failure becomes an extensive subject of analysis. Various arrangements in the system are compassed along with the utilization of some appropriate components. Application of a hydraulic accumulator is one among them. Benefits of accumulator is its multi-purpose usages like energy saving and pressure surge damping. This paper deals with the control of pressure surges in the hydraulic system and energy saving from the surges by using accumulator. For this purpose, the simulation of the hydraulic system is done in MATLAB/SimulinkR environment and an external disturbance is introduced to generate the pressure surge. The surge absorptivity of the accumulator is studied for different sizes at different pre-charged conditions of the accumulator. The discharge characteristics of different sized accumulators are also analyzed in this paper. It is observed that the ability to absorb the surge and stabilize the system is high in the smaller capacity accumulator. However the energy delivery time of larger sized accumulator is high.

  4. Graph based hydraulic modelling of pressure in water distribution networks

    CSIR Research Space (South Africa)

    Mpiana, LA

    2017-09-01

    Full Text Available given period of time and can be formulated as Where 𝐵 is the amount of incoming water at the node 𝑖 and 𝑡 is the delivery time period of time required. The amount of incoming water required at the node for a period of time is compared... to the water demand 𝐷𝑖 in order to decide on the operation of the pressure reduction valves. 𝐵𝑖𝑗 is the coefficient to evaluation in the required amount 𝐵 over a specific period of time. For a node 𝑖, 𝐵𝑖𝑗 is equal to 0...

  5. Hydraulic safety margins and embolism reversal in stems and leaves: Why are conifers and angiosperms so different?

    Science.gov (United States)

    Daniel M. Johnson; Katherine A. McCulloh; David R. Woodruff; Frederick C. Meinzer

    2012-01-01

    Angiosperm and coniferous tree species utilize a continuum of hydraulic strategies. Hydraulic safety margins (defined as differences between naturally occurring xylem pressures and pressures that would cause hydraulic dysfunction, or differences between pressures resulting in loss of hydraulic function in adjacent organs (e.g., stems vs. leaves) tend to be much greater...

  6. Safety of 5 MW district heating reactor (DHR) and hydraulic dynamic pressure drive control rods

    International Nuclear Information System (INIS)

    Wu Yuanqiang; Wang Dazhong

    1991-11-01

    The principles and movement characteristic of the hydraulic dynamic pressure drive for control rods in 5 MW district heating reactor are described with stress on analysis of its effects on reactor safety features. The drive is different from electric-magnetic drive for PWR or hydraulic drive for BWR. The drive cylinder is driven by dynamic pressure. In the new drive system, the reactor coolant (water) used as actuating medium is pressed by pump, then injected into a step cylinder which is set in the reactor core. The cylinder will move step by step by controlling flow, then the cylinder drives the neutron absorber and controls nuclear reaction. The drive is characterized by simplicity in structure, high reliability, inherent safety, reduction in reactor height, economy, etc

  7. Method for achieving hydraulic balance in typical Chinese building heating systems by managing differential pressure and flow

    DEFF Research Database (Denmark)

    Zhang, Lipeng; Xia, Jianjun; Thorsen, Jan Eric

    2017-01-01

    to a lack of pressure and flow control. This study investigated using pre-set radiator valves combined with differential pressure (DP) controllers to achieve hydraulic balance in building distribution systems, and consequently save energy and reduce the emissions. We considered a multi-storey building......Hydraulic unbalance is a common problem in Chinese district heating (DH) systems. Hydraulic unbalance has resulted in poor flow distribution among heating branches and overheating of apartments. Studies show that nearly 30% of the total heat supply is being wasted in Chinese DH systems due...... modelled in the IDA-ICE software, along with a self-developed mathematical hydraulic model to simulate its heat performance and hydraulic performance with various control scenarios. In contrast to the situation with no pressure or flow control, this solution achieves the required flow distribution...

  8. Loss-of-Fluid Test findings in pressurized water reactor core's thermal-hydraulic behavior

    International Nuclear Information System (INIS)

    Russell, M.

    1983-01-01

    This paper summarizes the pressurized water reactor (PWR) core's thermal-hydraulic behavior findings from experiments performed at the Loss-of-Fluid Test (LOFT) Facility at the Idaho National Engineering Laboratory. The potential impact of these findings on the safety and economics of PWR's generation of electricity is also discussed. Reviews of eight important findings in the core's physical behavior and in experimental methods are presented with supporting evidence

  9. Calculation and analysis of thermal–hydraulics fluctuations in pressurized water reactors

    International Nuclear Information System (INIS)

    Malmir, Hessam; Vosoughi, Naser

    2015-01-01

    Highlights: • Single-phase thermal–hydraulics noise equations are originally derived in the frequency domain. • The fluctuations of all the coolant parameters are calculated, without any simplifying assumptions. • The radial distribution of the temperature fluctuations in the fuel, gap and cladding are taken into account. • The closed-loop calculations are performed by means of the point kinetics noise theory. • Both the space- and frequency-dependence of the thermal–hydraulics fluctuations are analyzed. - Abstract: Analysis of thermal–hydraulics fluctuations in pressurized water reactors (e.g., local and global temperature or density fluctuations, as well as primary and charging pumps fluctuations) has various applications in calculation or measurement of the core dynamical parameters (temperature or density reactivity coefficients) in addition to thermal–hydraulics surveillance and diagnostics. In this paper, the thermal–hydraulics fluctuations in PWRs are investigated. At first, the single-phase thermal–hydraulics noise equations (in the frequency domain) are originally derived, without any simplifying assumptions. The fluctuations of all the coolant parameters, as well as the radial distribution of the temperature fluctuations in the fuel, gap and cladding are taken into account. Then, the derived governing equations are discretized using the finite volume method (FVM). Based on the discretized equations and the proposed algorithm of solving, a single heated channel noise calculation code (SHC-Noise) is developed, by which the steady-state and fluctuating parameters of PWR fuel assemblies can be calculated. The noise sources include the inlet coolant temperature and velocity fluctuations, in addition to the power density noises. The developed SHC-Noise code is benchmarked in different cases and scenarios. Furthermore, to show the effects of the power feedbacks, the closed-loop calculations are performed by means of the point kinetics noise

  10. A switched energy saving position controller for variable-pressure electro-hydraulic servo systems.

    Science.gov (United States)

    Tivay, Ali; Zareinejad, Mohammad; Rezaei, S Mehdi; Baghestan, Keivan

    2014-07-01

    The electro-hydraulic servo system (EHSS) demonstrates a relatively low level of efficiency compared to other available actuation methods. The objective of this paper is to increase this efficiency by introducing a variable supply pressure into the system and controlling this pressure during the task of position tracking. For this purpose, an EHSS structure with controllable supply pressure is proposed and its dynamic model is derived from the basic laws of physics. A switching control structure is then proposed to control both the supply pressure and the cylinder position at the same time, in a way that reduces the overall energy consumption of the system. The stability of the proposed switching control system is guaranteed by proof, and its performance is verified by experimental testing. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Hierarchical high-pressure hydraulic system for a continuously variable transmission; Mudan hensokuki no kaisoshiki koyuatsu system no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Tominaga, M; Wakahara, T; Hiraoka, Y; Ishimori, Y [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    A belt CVT system requires a large oil flow during shifts compared with a conventional automatic transmission. And the hydraulic pressure is higher for high-powered engines. As a result the oil pump is bigger and efficiency is lower(fuel consumption is higher). This system develops high pressure in three stages first reducing the hydraulic control system so that a small oil pump is attained. 8 figs.

  12. Hydraulic pressure pulses with elastic and plastic structural flexibility: test and analysis (LWBR Development Program)

    International Nuclear Information System (INIS)

    Schwirian, R.E.

    1978-03-01

    Pressure pulse tests were conducted with a flexible test section in a test vessel filled with room temperature water. The pressure pulses were generated with a drop hammer and piston pulse generator and were of a sufficient magnitude to cause plastic deformation of the test section. Because of the strong pressure relief effect of the deforming test section, pressure pulse magnitudes were below 265 psig in magnitude and had durations of 50 to 55 msecs. Calculations performed with the FLASH-35 bi-linear hysteresis model of structural deformation show good agreement with experiment. In particular, FLASH 35 adequately predicts the decrease in peak pressure and the increase in pulse duration due to elastic and plastic deformation of the test section. Predictions of flexible member motion are good, but are less satisfactory than the pressure pulse results due to uncertainties in the values of yield point and beyond yield stiffness used to model the various flexible members. Coupled with this is a strong sensitivity of the FLASH 35 predictions to the values of yield point and beyond yield stiffness chosen for the various flexible members. The test data versus calculation comparisons presented here provide preliminary qualification for FLASH 35 calculations of transient hydraulic pressures and pressure differentials in the presence of flexible structural members which deform both elastically and plastically

  13. Estimating Hydraulic Conductivities in a Fractured Shale Formation from Pressure Pulse Testing and 3d Modeling

    Science.gov (United States)

    Courbet, C.; DICK, P.; Lefevre, M.; Wittebroodt, C.; Matray, J.; Barnichon, J.

    2013-12-01

    In the framework of its research on the deep disposal of radioactive waste in shale formations, the French Institute for Radiological Protection and Nuclear Safety (IRSN) has developed a large array of in situ programs concerning the confining properties of shales in their underground research laboratory at Tournemire (SW France). One of its aims is to evaluate the occurrence and processes controlling radionuclide migration through the host rock, from the disposal system to the biosphere. Past research programs carried out at Tournemire covered mechanical, hydro-mechanical and physico-chemical properties of the Tournemire shale as well as water chemistry and long-term behaviour of the host rock. Studies show that fluid circulations in the undisturbed matrix are very slow (hydraulic conductivity of 10-14 to 10-15 m.s-1). However, recent work related to the occurrence of small scale fractures and clay-rich fault gouges indicate that fluid circulations may have been significantly modified in the vicinity of such features. To assess the transport properties associated with such faults, IRSN designed a series of in situ and laboratory experiments to evaluate the contribution of both diffusive and advective process on water and solute flux through a clay-rich fault zone (fault core and damaged zone) and in an undisturbed shale formation. As part of these studies, Modular Mini-Packer System (MMPS) hydraulic testing was conducted in multiple boreholes to characterize hydraulic conductivities within the formation. Pressure data collected during the hydraulic tests were analyzed using the nSIGHTS (n-dimensional Statistical Inverse Graphical Hydraulic Test Simulator) code to estimate hydraulic conductivity and formation pressures of the tested intervals. Preliminary results indicate hydraulic conductivities of 5.10-12 m.s-1 in the fault core and damaged zone and 10-14 m.s-1 in the adjacent undisturbed shale. Furthermore, when compared with neutron porosity data from borehole

  14. Orthogonal optimization of a water hydraulic pilot-operated pressure-reducing valve

    Science.gov (United States)

    Mao, Xuyao; Wu, Chao; Li, Bin; Wu, Di

    2017-12-01

    In order to optimize the comprehensive characteristics of a water hydraulic pilot-operated pressure-reducing valve, numerical orthogonal experimental design was adopted. Six parameters of the valve, containing diameters of damping plugs, volume of spring chamber, half cone angle of main spool, half cone angle of pilot spool, mass of main spool and diameter of main spool, were selected as the orthogonal factors, and each factor has five different levels. An index of flowrate stability, pressure stability and pressure overstrike stability (iFPOS) was used to judge the merit of each orthogonal attempt. Embedded orthogonal process turned up and a final optimal combination of these parameters was obtained after totally 50 numerical orthogonal experiments. iFPOS could be low to a fairly low value which meant that the valve could have much better stabilities. During the optimization, it was also found the diameters of damping plugs and main spool played important roles in stability characteristics of the valve.

  15. Aperiodic pressure pulsation under non optimal hydraulic turbine regimes at low swirl number

    Science.gov (United States)

    Skripkin, S. G.; Tsoy, M. A.; Kuibin, P. A.; Shtork, S. I.

    2017-09-01

    Off-design operating conditions of hydraulic turbines is hindered by pressure fluctuations in the draft tube of the turbine. A precessing helical vortex rope develops, which imperils the mechanical structure and limits the operation flexibility of hydropower station. Understanding of the underlying instabilities of precessing vortex rope at low swirl number is incomplete. In this paper flow regimes with different residual swirl is analysed, particular attention is paid to the regime with a small swirl parameter. Study defines upper and low boundaries of regime where aperiodic pressure surge is observed. Flow field at the runner exit is investigated by Laser Doppler Velocimetry and high-speed visualizations, which are complemented draft tube wall pressure measurements.

  16. The Study on the Measurement and Testing Technology of the HMCVT Hydraulic Pressure Based on the Data Fusion Technology

    International Nuclear Information System (INIS)

    Cheng, G W; Zhou, Z L; Men, Q Y; Deng, C N

    2006-01-01

    The pressure of the hydro-mechanical continuously variable transmission (HMCVT) is not only one of the major factors affecting the performance of the power train but also the major control parameter of the HMCVT control system. So how to improve the high accuracy hydraulic pressure parameter for the HMCVT control system will be one of the key technologies in system development. Based on the HMCVT test system for a certain tracked vehicle, the hydraulic pressure is studied, and multi-sensor data fusion technology based on Taylor polynomial regression equation is put forward, which turn out to improve the performance of the pressure sensor. Utilizing the above-mentioned method, the ability of antijamming of the hydraulic screen pressure system of the HMCVT is effectively improved, and the validity of the test data in the test system is improved too

  17. Theoretical study of hydraulic jump during circular horizontal hot leg injection in pressurized water reactor

    International Nuclear Information System (INIS)

    El Hawary, Shehab; Abu-Elyazeed, Osayed S.M.; Fahmy, Adel Alyan; Meglaa, Khairy

    2016-01-01

    Highlights: • The model is developed to predict the occurrence of onset hydraulic jump in a circular pipe. • Theoretical results are in agreement with experimental results and theory. • Effects of diameter of the injection pipe, Froude number and injected coolant mass are studied. - Abstract: One important phenomenon occurring during Loss of Coolant Accident (LOCA) is Counter-Current Flow Limitation (CCFL). The incidence of such CCFL is introduced by the onset of hydraulic jump. In the present work, a one dimensional model was modified to fit circular hot channel. The model was used to study the factors affecting the initial Froude number, the location of the occurrence of the hydraulic jump, and the critical coolant flow depth during circular horizontal hot leg injection in US-APWR Mitsubishi Reactor. The results showed good agreement with published experimental data of the Upper Plenum Test Facility (UPTF) at Mannheim, Germany. It was found that higher injected coolant mass flow rate increases the initial Froude number, the location of the occurrence of the hydraulic jump, and the critical injection depth divided by the diameter of the injection pipe. Such behavior is thought to be due to the increase of the inertia force by increasing of the injected coolant mass flow rate and the inverse of the diameter of the injection pipe. It was found also that, the location of the occurrence of hydraulic jump increases with decreasing load effect. Therefore, these results reveal that the avoidance of CCFL as well as hydraulic jump through hot leg at maximum load can be achieved by decreasing the distance between the injection point and the pressure vessel to below 0.3 m, and with diameter of 4 in (10.16 cm) as the design diameter of the injection pipe in US-APWR Mitsubishi Reactor. Moreover, the maximum critical depth (56 cm) is less than the diameter of the hot leg (78.74 cm) at an injected coolant mass flow of 400 kg/s, and with diameter of 4 in (10.16 cm) as the

  18. Pressurized thermal shock. Thermo-hydraulic conditions in the CNA-I reactor pressure vessel

    International Nuclear Information System (INIS)

    Ventura, Mirta A.; Rosso, Ricardo D.

    2002-01-01

    In this paper we analyze several reports issued by the Utility (Nucleo Electrica S.A.) and related to Reactor Pressure Vessel (RPV) phenomena in the CNA-I Nuclear Power Plant. These analyses are aimed at obtaining conclusions and establishing criteria ensuring the RPV integrity. Special attention was given to the effects ECCS cold-water injection at the RPV down-comer leading to pressurized thermal shock scenarios. The results deal with hypothetical primary system pipe breaks of different sizes, the inadvertent opening of the pressurizer safety valve, the double guillotine break of a live steam line in the containment and the inadvertent actuation pressurizer heaters. Modeling conditions were setup to represent experiments performed at the UPTF, under the hypothesis that they are representative of those that, hypothetically, may occur at the CNA-I. No system scaling analysis was performed, so this assertion and the inferred conclusions are no fully justified, at least in principle. The above mentioned studies, indicate that the RPV internal wall surface temperature will be nearly 40 degree. It was concluded that they allowed a better approximation of PTS phenomena in the RPV of the CNA-I. Special emphasis was made on the influence of the ECCS systems on the attained RPV wall temperature, particularly the low-pressure TJ water injection system. Some conservative hypothesis made, are discussed in this report. (author)

  19. Comparison between gradient-dependent hydraulic conductivities of roots using the root pressure probe: the role of pressure propagations and implications for the relative roles of parallel radial pathways.

    Science.gov (United States)

    Bramley, Helen; Turner, Neil C; Turner, David W; Tyerman, Stephen D

    2007-07-01

    Hydrostatic pressure relaxations with the root pressure probe are commonly used for measuring the hydraulic conductivity (Lp(r)) of roots. We compared the Lp(r) of roots from species with different root hydraulic properties (Lupinus angustifolius L. 'Merrit', Lupinus luteus L. 'Wodjil', Triticum aestivum L. 'Kulin' and Zea mays L. 'Pacific DK 477') using pressure relaxations, a pressure clamp and osmotic gradients to induce water flow across the root. Only the pressure clamp measures water flow under steady-state conditions. Lp(r) determined by pressure relaxations was two- to threefold greater than Lp(r) from pressure clamps and was independent of the direction of water flow. Lp(r) (pressure clamp) was two- to fourfold higher than for Lp(r) (osmotic) for all species except Triticum aestivum where Lp(r) (pressure clamp) and Lp(r) (osmotic) were not significantly different. A novel technique was developed to measure the propagation of pressure through roots to investigate the cause of the differences in Lp(r). Root segments were connected between two pressure probes so that when root pressure (P(r)) was manipulated by one probe, the other probe recorded changes in P(r). Pressure relaxations did not induce the expected kinetics in pressure in the probe at the other end of the root when axial hydraulic conductance, and probe and root capacitances were accounted for. An electric circuit model of the root was constructed that included an additional capacitance in the root loaded by a series of resistances. This accounted for the double exponential kinetics for intact roots in pressure relaxation experiments as well as the reduced response observed with the double probe experiments. Although there were potential errors with all the techniques, we considered that the measurement of Lp(r) using the pressure clamp was the most unambiguous for small pressure changes, and provided that sufficient time was allowed for pressure propagation through the root. The differences in

  20. Modeling Thermal Pressurization Around Shallow Dikes Using Temperature-Dependent Hydraulic Properties: Implications for Deformation Around Intrusions

    Science.gov (United States)

    Townsend, Meredith R.

    2018-01-01

    Pressurization and flow of groundwater around igneous intrusions depend in part on the hydraulic diffusivity of the host rocks and processes that enhance diffusivity, such as fracturing, or decrease diffusivity, such as mineral precipitation during chemical alteration. Characterizing and quantifying the coupled effects of alteration, pore pressurization, and deformation have significant implications for deformation around intrusions, geothermal energy, contact metamorphism, and heat transfer at mid-ocean ridges. Fractures around dikes at Ship Rock, New Mexico, indicate that pore pressures in the host rocks exceeded hydrostatic conditions by at least 15 MPa following dike emplacement. Hydraulic measurements and petrographic analysis indicate that mineral precipitation clogged the pores of the host rock, reducing porosity from 0.25 to reducing permeability by 5 orders of magnitude. Field data from Ship Rock are used to motivate and constrain numerical models for thermal pore fluid pressurization adjacent to a meter-scale dike, using temperature-dependent hydraulic properties in the host rock as a proxy for porosity loss by mineral precipitation during chemical alteration. Reduction in permeability by chemical alteration has a negligible effect on pressurization. However, reduction in porosity by mineral precipitation increases fluid pressure by constricting pore volume and is identified as a potentially significant source of pressure. A scaling relationship is derived to determine when porosity loss becomes important; if permeability is low enough, pressurization by porosity loss outweighs pressurization by thermal expansion of fluids.

  1. Suppression of Squeal Noise Excited by the Pressure Pulsation from the Flapper-Nozzle Valve inside a Hydraulic Energy System

    Directory of Open Access Journals (Sweden)

    Meng Chen

    2018-04-01

    Full Text Available Squeal noise often occurs in a two-stage electrohydraulic servo-valve, which is an unfavorable issue of modern hydraulic energy systems. The root causes of such noise from the servo-valve are still unclear. The objective of this paper is to explore the noise mechanism in a servo-valve excited by the pressure pulsations from the hydraulic energy system perspective. The suppressing capability of squeal noise energy is investigated by changing the pressure pulsation frequency and natural frequency of the flapper-armature assembly. The frequencies of the pressure pulsations are adjusted by setting different speeds of the hydraulic pump varying from 10,400–14,400 rpm, and two flapper-armature assemblies with different armature lengths are used in the tested hydraulic energy system. The first eight vibration mode shapes and natural frequencies of the flapper-armature assembly are obtained by numerical modal analysis using two different armature lengths. The characteristics of pressure pulsations at the pump outlet and in the chamber of the flapper-nozzle valve, armature vibration and noise are tested and compared with the natural frequencies of the flapper-armature assembly. The results reveal that the flapper-armature assembly vibrates and makes the noise with the same frequencies as the pressure pulsations inside the hydraulic energy system. Resonance appears when the frequency of the pressure pulsations coincides with the natural frequency of the flapper-armature assembly. Therefore, it can be concluded that the pressure pulsation energy from the power supply may excite the vibration of the flapper-armature assembly, which may consequently cause the squeal noise inside the servo-valve. It is verified by the numerical simulations and experiments that setting the pressure pulsation frequencies different from the natural frequencies of the flapper-armature assembly can suppress the resonance and squeal noise.

  2. Effect of persistent high intraocular pressure on microstructure and hydraulic permeability of trabecular meshwork

    International Nuclear Information System (INIS)

    Mei Xi; Ren Lin; Xu Qiang; Liu Zhi-Cheng; Zheng Wei

    2015-01-01

    As the aqueous humor leaves the eye, it first passes through the trabecular meshwork (TM). Increased flow resistance in this region causes elevation of intraocular pressure (IOP), which leads to the occurrence of glaucoma. To quantitatively evaluate the effect of high IOP on the configuration and hydraulic permeability of the TM, second harmonic generation (SHG) microscopy was used to image the microstructures of the TM and adjacent tissues in control (normal) and high IOP conditions. Enucleated rabbit eyes were perfused at a pressure of 60 mmHg to achieve the high IOP. Through the anterior chamber of the eye, in situ images were obtained from different depths beneath the surface of the TM. Porosity and specific surface area of the TM in control and high IOP conditions were then calculated to estimate the effect of the high pressure on the permeability of tissue in different depths. We further photographed the histological sections of the TM and compared the in situ images. The following results were obtained in the control condition, where the region of depth was less than 55 μm with crossed branching beams and large pores in the superficial TM. The deeper meshwork is a silk-like tissue with abundant fluorescence separating the small size of pores. The total thickness of pathway tissues composed of TM and juxtacanalicular (JCT) is more than 100 μm. After putting a high pressure on the inner wall of the eye, the TM region progressively collapses and decreases to be less than 40 μm. Fibers of the TM became dense, and the porosity at 34 μm in the high IOP condition is comparable to that at 105 μm in the control condition. As a consequent result, the permeability of the superficial TM decreases rapidly from 120 μm 2 to 49.6 μm 2 and that of deeper TM decreases from 1.66 μm 2 to 0.57 μm 2 . Heterogeneity reflected by descent in permeability reduces from 12.4 μm of the control condition to 3.74 μm of the high IOP condition. The persistently high IOP makes the

  3. Energy-saving analysis of hydraulic hybrid excavator based on common pressure rail.

    Science.gov (United States)

    Shen, Wei; Jiang, Jihai; Su, Xiaoyu; Karimi, Hamid Reza

    2013-01-01

    Energy-saving research of excavators is becoming one hot topic due to the increasing energy crisis and environmental deterioration recently. Hydraulic hybrid excavator based on common pressure rail (HHEC) provides an alternative with electric hybrid excavator because it has high power density and environment friendly and easy to modify based on the existing manufacture process. This paper is focused on the fuel consumption of HHEC and the actuator dynamic response to assure that the new system can save energy without sacrificing performance. Firstly, we introduce the basic principle of HHEC; then, the sizing process is presented; furthermore, the modeling period which combined mathematical analysis and experiment identification is listed. Finally, simulation results show that HHEC has a fast dynamic response which can be accepted in engineering and the fuel consumption can be reduced 21% to compare the original LS excavator and even 32% after adopting another smaller engine.

  4. Parametric studies on containment thermal hydraulic loads during high pressure melt ejection in a BWR

    Energy Technology Data Exchange (ETDEWEB)

    Silde, A.; Lindholm, I. [VTT Energy, Espoo (Finland)

    1997-12-01

    The containment thermal hydraulic loads during high pressure melt ejection in a Nordic BWR are studied parametrically with the CONTAIN and the MELCOR codes. The work is part of the Nordic RAK-2 project. The containment analyses were divided into two categories according to composition of the discharged debris: metallic and oxidic debris cases. In the base case with highly metallic debris, all sources from the reactor coolant system to the containment were based on the MELCOR/BH calculation. In the base case with the oxidic debris, the source data was specified assuming that {approx} 15% of the whole core material inventory and 34,000 kg of saturated water was discharged from the reactor pressure vessel (RPV) during 30 seconds. In this case, the debris consisted mostly of oxides. The highest predicted containment pressure peaks were about 8.5 bar. In the scenarios with highly metallic debris source, very high gas temperature of about 1900 K was predicted in the pedestal, and about 1400 K in the upper drywell. The calculations with metallic debris were sensititive to model parameters, like the particle size and the parameters, which control the chemical reaction kinetics. In the scenarios with oxidic debris source, the predicted pressure peaks were comparable to the cases with the metallic debris source. The maximum gas temperatures (about 450-500 K) in the containment were, however, significantly lower than in the respective metallic debris case. The temperatures were also insensitive to parametric variations. In addition, one analysis was performed with the MELCOR code for benchmarking of the MELCOR capabilities against the more detailed CONTAIN code. The calculations showed that leak tightness of the containment penetrations could be jeopardized due to high temperature loads, if a high pressure melt ejection occurred during a severe accident. Another consequence would be an early containment venting. (au). 28 refs.

  5. Combined hydraulic and biomass power - an answer to economic and ecological adaptation pressure on the energy supply system

    International Nuclear Information System (INIS)

    Pistauer, M.

    1991-01-01

    On the large scale, there will be an economic pressure in the European Communities on coal and oil from the CO 2 taxes. The economic and ecological advantages of a combination of hydraulic and biomass power in Austria are emphasized. In particular a biomass remote heating pilot project is announced. (Quittner)

  6. Thermo hydraulic analysis of narrow channel effect in supercritical-pressure light water reactor

    International Nuclear Information System (INIS)

    Zhou Tao; Chen Juan; Cheng Wanxu

    2012-01-01

    Highlights: ► Detailed thermal analysis with different narrow gaps between fuel rods is given. ► Special characteristics of narrow channels effect on heat transfer in supercritical pressure are shown. ► Reasonable size selection of gaps between fuel rods is proposed for SCWR. - Abstract: The size of the gap between fuel rods has important effects on flow and heat transfer in a supercritical-pressure light water reactor. Based on thermal analysis at different coolant flow rates, the reasonable value range of gap size between fuel rods is obtained, for which the maximum cladding temperature safety limits and installation technology are comprehensively considered. Firstly, for a given design flow rate of coolant, thermal hydraulic analysis of supercritical pressure light water reactor with different gap sizes is provided by changing the fuel rod pitch only. The results show that, by means of reducing the gap size between fuel rods, the heat transfer coefficients between coolant and fuel rod, as well as the heat transfer coefficient between coolant and water rod, would both increase noticeably. Furthermore, the maximum cladding temperature will significantly decrease when the moderator temperature is decreased but coolant temperature remains essentially constant. Meanwhile, the reduction in the maximum cladding temperature in the inner assemblies is much larger than that in the outer assemblies. In addition, the maximum cladding temperature could be further reduced by means of increasing coolant flow rate for each gap size. Finally, the characteristics of narrow channels effect are proposed, and the maximum allowable gap between fuel rods is obtained by making full use of the enhancing narrow channels effect on heat transfer, and concurrently considering installation. This could provide a theoretical reference for supercritical-pressure light water reactor design optimization, in which the effects of gap size and flow rate on heat transfer are both considered.

  7. Pressure, flow and hydraulic interference measurements in ONKALO at Olkiluoto, drillholes ONK-PP262 and ONK-PP274

    International Nuclear Information System (INIS)

    Hurmerinta, E.; Pekkanen, J.; Komulainen, J.; Rouhiainen, P.

    2012-01-01

    The general purpose of these studies is to characterize the fracture network and groundwater flow properties in a volume of rock, which is representative of the rock close to deposition holes. As a part of the studies hydraulic tests and flow measurements were applied in two drillholes in hydraulically poorly conductive bedrock. This report presents the principles of the methods as well as the results of the measurements carried out in the underground facilities of ONKALO. The measurements were conducted in drillholes ONK-PP262 and ONK-PP274 between May 9, 2010 and June 9, 2011. The aim of the measurements was to obtain pressure in the closed drillholes, to detect water yielding fractures by flow measurements, to obtain transmissivity with overpressure and drawdown tests and to study hydraulic interference between the drillholes by cross-hole hydraulic tests. The PFL DIFF probe was used to detect flow within single fractures in the drillhole. Transmissive water yielding fractures were found at depths 17.9 m, 16.9 m and 16.4 m in ONK-PP262 and at depths 19.8 m and 19.5 m in ONK-PP274. The cross-hole hydraulic tests included three basic phases. Flow was measured in one drillhole when the other drillhole was open, closed or overpressurized. The cross-hole hydraulic tests were carried out to both directions in the two drillholes. (orig.)

  8. Instance Analysis for the Error of Three-pivot Pressure Transducer Static Balancing Method for Hydraulic Turbine Runner

    Science.gov (United States)

    Weng, Hanli; Li, Youping

    2017-04-01

    The working principle, process device and test procedure of runner static balancing test method by weighting with three-pivot pressure transducers are introduced in this paper. Based on an actual instance of a V hydraulic turbine runner, the error and sensitivity of the three-pivot pressure transducer static balancing method are analysed. Suggestions about improving the accuracy and the application of the method are also proposed.

  9. Thermal-hydraulic analyses of pressurized-thermal-shock-induced vessel ruptures

    International Nuclear Information System (INIS)

    Dobranich, D.

    1982-05-01

    A severe overcooling transient was postulated to produce vessel wall temperatures below the nil-ductility transition temperature which in conjunction with system repressurization, led to vessel rupture at the core midplane. Such transients are referred to as pressurized-thermal-shock transients. A wide range of vessel rupture sizes were investigated to assess the emergency system's ability to cool the fuel rods. Ruptures greater than approximately 0.015 m 2 produced flows greater than those of the emergency system and resulted in core uncovery and subsequent core damage

  10. Basic data generation and pressure loss coefficient evaluation for HANARO core thermal-hydraulic analyses

    International Nuclear Information System (INIS)

    Chae, Hee Taek; Lee, Kye Hong

    1999-06-01

    MATRA-h, a HANARO subchannel analysis computer code, is used to evaluate thermal margin of the HANARO fuel. It's capability includes the assessments of CHF, ONB margin, and fuel temperature. In this report, basic input data and core design parameters required to perform the subchannel analysis with MATRA-h code are collected. These data include the subchannel geometric data, thermal-hydraulic correlations, empirical constants and material properties. The friction and form loss coefficients of the fuel assemblies were determined based on the results of the pressure drop test. At the same time, different form loss coefficients at the end plates and spacers are evaluated for various subchannels. The adequate correlations are applied to the evaluation of the form loss coefficients for various subchannels, which are corrected by measured values in order to have a same pressure drop at each flow channel. These basic input data and design parameters described in this report will be applied usefully to evaluate the thermal margin of the HANARO fuel. (author). 11 refs., 13 tabs., 11 figs

  11. Effects of transmembrane hydraulic pressure on performance of forward osmosis membranes.

    Science.gov (United States)

    Coday, Bryan D; Heil, Dean M; Xu, Pei; Cath, Tzahi Y

    2013-03-05

    Forward osmosis (FO) is an emerging membrane separation process that continues to be tested and implemented in various industrial water and wastewater treatment applications. The growing interests in the technology have prompted laboratories and manufacturers to adopt standard testing methods to ensure accurate comparison of membrane performance under laboratory-controlled conditions; however, standardized methods might not capture specific operating conditions unique to industrial applications. Experiments with cellulose triacetate (CTA) and polyamide thin-film composite (TFC) FO membranes demonstrated that hydraulic transmembrane pressure (TMP), common in industrial operation of FO membrane elements, could affect membrane performance. Experiments were conducted with three FO membranes and with increasing TMP up to a maximum of 50 psi (3.45 bar). The feed solution was a mixture of salts and the draw solution was either a NaCl solution or concentrated seawater at similar osmotic pressure. Results revealed that TMP minimally affected water flux, reverse salt flux (RSF), and solute rejection of the CTA membrane. However, water flux through TFC membranes might slightly increase with increasing TMP, and RSF substantially declines with increasing TMP. It was observed that rejection of feed constituents was influenced by TMP and RSF.

  12. Recent experimental data may point to a greater role for osmotic pressures in the subsurface

    Science.gov (United States)

    Neuzil, C.E.; Provost, A.M.

    2009-01-01

    Uncertainty about the origin of anomalous fluid pressures in certain geologic settings has caused researchers to take a second look at osmosis, or flow driven by chemical potential differences, as a pressure‐generating process in the subsurface. Interest in geological osmosis has also increased because of an in situ experiment by Neuzil (2000) suggesting that Pierre Shale could generate large osmotic pressures when highly compacted. In the last few years, additional laboratory and in situ experiments have greatly increased the number of data on osmotic properties of argillaceous formations, but they have not been systematically examined. In this paper we compile these data and explore their implications for osmotic pressure generation in subsurface systems. Rather than base our analysis on osmotic efficiencies, which depend strongly on concentration, we calculated values of a quantity we term osmotic specific surface area (Aso) that, in principle, is a property of the porous medium only. The Aso values are consistent with a surprisingly broad spectrum of osmotic behavior in argillaceous formations, and all the formations tested exhibited at least a modest ability to generate osmotic pressure. It appears possible that under appropriate conditions some formations can be highly effective osmotic membranes able to generate osmotic pressures exceeding 30 MPa (3 km of head) at porosities as high as ∼0.1 and pressures exceeding 10 MPa at porosities as high as ∼0.2. These findings are difficult to reconcile with the lack of compelling field evidence for osmotic pressures, and we propose three explanations for the disparity: (1) Our analysis is flawed and argillaceous formations are less effective osmotic membranes than it suggests; (2) the necessary subsurface conditions, significant salinity differences within intact argillaceous formations, are rare; or (3) osmotic pressures are unlikely to be detected and are not recognized when encountered. The last possibility

  13. Effectiveness of Sealed Double-Ring Infiltrometers trademark and effects of changes in atmospheric pressure on hydraulic conductivity

    International Nuclear Information System (INIS)

    McMullin, S.R.

    1994-01-01

    The Savannah River Site is currently evaluating some 40 hazardous and radioactive-waste sites for remediation. Among the remedial alternatives considered is closure using a kaolin clay cap. The hydraulic conductivity suggested by the US Environmental Protection Agency is 1.0 x 10 -7 cm/sec. One instrument to measure this value is the Sealed Double-Ring Infiltrometer trademark (SDRI). Six SDRI were recently installed on a kaolin test cap. Test results demonstrated uniform performance of these instruments. However, the test data showed as much as an order of magnitude of variation over time. This variation is attributed to both internal structural heterogeneity and variable external boundary conditions. The internal heterogeneity is caused by construction variability within a specified range of moisture and density. The external influences considered are temperature and barometric pressure. Temperature was discharged as a source of heterogeneity because of a lack of correlation with test data and a negligible impact from the range of variability. However, a direct correlation was found between changes in barometric pressure and hydraulic conductivity. This correlation is most pronounced when pressure changes occur over a short period of time. Additionally, this correlation is related to a single soil layer. When the wetting front passes into a more porous foundation layer, the correlation with pressure changes disappears. Conclusions are that the SDRI performs adequately, with good repeatability of results. The duration of test is critical to assure a statistically valid data set. Data spikes resulting from pressure changes should be identified, and professional judgment used to determine the representative hydraulic conductivity. Further evaluation is recommended to determine the impact of pressure change on the actual hydraulic conductivity

  14. Thermo-hydraulic consequence of pressure suppression containment vessel during blowdown, 2

    International Nuclear Information System (INIS)

    Aya, Izuo; Nariai, Hideki; Kobayashi, Michiyuki

    1980-01-01

    As a part of the safety research works for the integral-type marine reactor, an analytical code SUPPAC-2V was developed to simulate the thermo-hydraulic consequence of a pressure suppression containment system during blowdown and the code was applied to the Model Experimental Facility of the Safety of Integral Type Marine Reactors (explained already in Part 1). SUPPAC-2V is much different from existing codes in the following points. A nonhomogeneous model for the gaseous region in the drywell, a new correlation for condensing heat transfer coefficient at drywell wall based on existing data and approximation of air bubbles in wetwell water by one dimensional bubble rising model are adopted in this code. In comparing calculational results with experimental results, values of predominant input parameters were evaluated and discussed. Moreover, the new code was applied also to the NSR-7 marine reactor, conceptually designed at the Shipbuilding Research Association in Japan, of which suppression system had been already analysed by CONTEMPT-PS. (author)

  15. Thermal-hydraulic and neutronic analysis of pressurized water reactor cores

    International Nuclear Information System (INIS)

    Alves, C.H.

    1982-01-01

    A computational code, named CANAL2, was developed for the simulation of the steady-state and transient behaviour of a Pressurized Water Reactor core. The conservation equations for the control volumes are obtained by area-averaging of the two-fluid model conservation equations and reducing them to the drift-flux model formulation. The resulting equations are aproximated by finite differences and solved by a marching-type numerical scheme. The model takes into account the exchange of mass, momentum and energy between adjacent subchannels of a fuel bundle. Turbulent mixing and diversion crossflow are considered. Correlations are provided for several heat trans and flow regimes and selected according to the local conditons. During transients core power can be evaluated by a point-Kinetics model. Fuel and coolant temperatures are feedback to the neutronics. The heat conduction equation is solved in the fuel using the Crank-Nicolson scheme. Temperature-dependent correlations are provided for the fuel and cladding thermal conductivities. Several runs were made with the code CANAL2 using the available experimental and calculated data in the open literature. Results indicate that CANAL2 is a good calculational tool for the thermal-hydraulics of PWR cores. A few refinements will make the code useful for design. (Author) [pt

  16. Stochastic estimation approach for the evaluation of thermal-hydraulic parameters in pressurized water reactors

    International Nuclear Information System (INIS)

    Shieh, D.J.; Upadhyaya, M.G.

    1986-01-01

    A method based on the extended Kalman filter is developed for the estimation of the core coolant mass flow rate in pressurized water reactors. The need for flow calibration can be avoided by a direct estimation of this parameter. A reduced-order neutronic and thermal-hydraulic model is developed for the Loss-of-Fluid Test (LOFT) reactor. The neutron detector and core-exit coolant temperature signals from the LOFT reactor are used as measurements in the parameter estimation algorithm. The estimation sensitivity to model uncertainties was evaluated using the ambiguity function analysis. This also provides a lower bound on the measurement sample size necessary to achieve a certain estimation accuracy. A sequential technique was developed to minimize the computational effort needed to discretize the continuous time equations, and thus achieve faster convergence to the true parameter value. The performance of the stochastic approximation method was first evaluated using simulated random data, and then applied to the estimation of coolant flow rate using the operational data from the LOFT reactor at 100 and 65% flow rate conditions

  17. Hydraulic experiment on evaluation method of tsunami wave pressure using inundation depth and velocity in front of land structure

    International Nuclear Information System (INIS)

    Arimitsu, Tsuyoshi; Ooe, Kazuya; Kawasaki, Koji

    2012-01-01

    Hydraulic experiments were conducted to estimate tsunami wave pressure acting on several different types of land structures and examine the influence of a seawall in front of the structure on tsunami wave pressure. Wave pressures were measured at some points on the structure. The existing hydrostatic formula tended to underestimate tsunami wave pressure under the condition of inundation flow with large Froude number. Estimation method of tsunami wave pressure using inundation depth and horizontal velocity at the front of the structure was proposed based on the experimental results. It was confirmed from comparison with the experiments that the vertical distribution of the maximum tsunami wave pressure can be reproduced by employing the proposed method in this study. (author)

  18. Validation of the thermal-hydraulic system code ATHLET based on selected pressure drop and void fraction BFBT tests

    Energy Technology Data Exchange (ETDEWEB)

    Di Marcello, Valentino, E-mail: valentino.marcello@kit.edu; Escalante, Javier Jimenez; Espinoza, Victor Sanchez

    2015-07-15

    Highlights: • Simulation of BFBT-BWR steady-state and transient tests with ATHLET. • Validation of thermal-hydraulic models based on pressure drops and void fraction measurements. • TRACE system code is used for the comparative study. • Predictions result in a good agreement with the experiments. • Discrepancies are smaller or comparable with respect to the measurements uncertainty. - Abstract: Validation and qualification of thermal-hydraulic system codes based on separate effect tests are essential for the reliability of numerical tools when applied to nuclear power plant analyses. To this purpose, the Institute for Neutron Physics and Reactor Technology (INR) at the Karlsruhe Institute of Technology (KIT) is involved in various validation and qualification activities of different CFD, sub-channel and system codes. In this paper, the capabilities of the thermal-hydraulic code ATHLET are assessed based on the experimental results provided within the NUPEC BFBT benchmark related to key Boiling Water Reactors (BWR) phenomena. Void fraction and pressure drops measurements in the BFBT bundle performed under steady-state and transient conditions which are representative for e.g. turbine trip and recirculation pump trip events, are compared with the numerical results of ATHLET. The comparison of code predictions with the BFBT data has shown good agreement given the experimental uncertainty and the results are consistent with the trends obtained with similar thermal-hydraulic codes.

  19. Reactive rise in blood pressure upon cuff inflation: cuff inflation at the arm causes a greater rise in pressure than at the wrist in hypertensive patients.

    Science.gov (United States)

    Charmoy, Alexia; Würzner, Grégoire; Ruffieux, Christiane; Hasler, Christopher; Cachat, François; Waeber, Bernard; Burnier, Michel

    2007-10-01

    Cuff inflation at the arm is known to cause an instantaneous rise in blood pressure, which might be due to the discomfort of the procedure and might interfere with the precision of the blood pressure measurement. In this study, we compared the reactive rise in blood pressure induced by cuff inflation when the cuff was placed at the upper arm level and at the wrist. The reactive rise in systolic and diastolic blood pressure to cuff inflation was measured in 34 normotensive participants and 34 hypertensive patients. Each participant was equipped with two cuffs, one around the right upper arm (OMRON HEM-CR19, 22-32 cm) and one around the right wrist (OMRON HEM-CS 19, 17-22 cm; Omron Health Care Europe BV, Hoofddorp, The Netherlands). The cuffs were inflated in a double random order (maximal cuff pressure and position of the cuff) with two maximal cuff pressures: 180 and 240 mmHg. The cuffs were linked to an oscillometric device (OMRON HEM 907; Omron Health Care). Simultaneously, blood pressure was measured continuously at the middle finger of the left hand using photoplethysmography. Three measurements were made at each level of blood pressure at the arm and at the wrist, and the sequence of measurements was randomized. In normotensive participants, no significant difference was observed in the reactive rise in blood pressure when the cuff was inflated either at the arm or at the wrist irrespective of the level of cuff inflation. Inflating a cuff at the arm, however, induced a significantly greater rise in blood pressure than inflating it at the wrist in hypertensive participants for both systolic and diastolic pressures (Pblood pressure response to cuff inflation was independent of baseline blood pressure. The results show that in hypertensive patients, cuff inflation at the wrist produces a smaller reactive rise in blood pressure. The difference between the arm and the wrist is independent of the patient's level of blood pressure.

  20. Adaptive Control System of Hydraulic Pressure Based on The Mathematical Modeling

    Science.gov (United States)

    Pilipenko, A. V.; Pilipenko, A. P.; Kanatnikov, N. V.

    2016-04-01

    In this paper, the authors highlight the problem of replacing an old heavy industrial equipment, and offer the replacement of obsolete control systems on the modern adaptive control system, which takes into account changes in the hydraulic system of the press and compensates them with a corrective action. The proposed system can reduce a water hammer and thereby increase the durability of the hydraulic system and tools.

  1. Predicting the Occurrence of Hydraulic Fracture in Grouting Operations Based on the Pressure in the Penetrated Cement Grout

    Directory of Open Access Journals (Sweden)

    Hassan Bakhshandeh Amnieh

    2017-12-01

    Full Text Available Cement grouting is an operation often carried out to consolidate and seal the rock mass in dam sites and tunnels. The quality and efficiency of a grouting operation depends on various factors such as water take, grout properties and grouting pressure. One of the parameters which have the highest effect is pressure since the application of excessive pressure causes the hydraulic fracture phenomenon to occur in the rock mass and too little pressure leads to incomplete grouting and failure to seal the site in a perfect manner. Mathematical modeling is used for the first time in this study to predict and determine the optimum pressure. Thus, the joints that exist in the rock mass are simulated using cylindrical shell model. The joint surroundings are also modeled through Pasternak environment. To obtain equations governing the joints and the surroundings, energy method is used accompanied by Hamilton principle. In the end, an analytical solution method is used to obtain the maximum grouting pressure. In order to validate the modeling, the grouting pressure values obtained by the model were used in the sites of Seymareh and Aghbolagh dams and the relative error rates were measured considering the differences between calculated and actual pressures. Modeling in the examined sections of Seymareh dam showed 29.61, 5.57, 21.98, 32.50 and 9.09 percent error rates and in the sections of Aghbolagh dam it rendered the values of 4.32, 5.40 and 2.96 percent. The results indicate that this modeling can be used to estimate the amount of pressure for hydraulic fracture in grouting, to predict it and to prevent it.

  2. Comparative study of Thermal Hydraulic Analysis Codes for Pressurized Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yang Hoon; Jang, Mi Suk; Han, Kee Soo [Nuclear Engineering Service and Solution Co. Ltd., Daejeon (Korea, Republic of)

    2015-05-15

    Various codes are used for the thermal hydraulic analysis of nuclear reactors. The use of some codes among these is limited by user and some codes are not even open to general person. Thus, the use of alternative code is considered for some analysis. In this study, simple thermal hydraulic behaviors are analyzed using three codes to show that alternative codes are possible for the analysis of nuclear reactors. We established three models of the simple u-tube manometer using three different codes. RELAP5 (Reactor Excursion and Leak Analysis Program), SPACE (Safety and Performance Analysis CodE for nuclear power Plants), GOTHIC (Generation of Thermal Hydraulic Information for Containments) are selected for this analysis. RELAP5 is widely used codes for the analysis of system behavior of PWRs. SPACE has been developed based on RELAP5 for the analysis of system behavior of PWRs and licensing of the code is in progress. And GOTHIC code also has been widely used for the analysis of thermal hydraulic behavior in the containment system. The internal behavior of u-tube manometer was analyzed by RELAP5, SPACE and GOTHIC codes. The general transient behavior was similar among 3 codes. However, the stabilized status of the transient period analyzed by REPAP5 was different from the other codes. It would be resulted from the different physical models used in the other codes, which is specialized for the multi-phase thermal hydraulic behavior analysis.

  3. Thermo-hydraulic behavior of saturated steam-water mixture in pressure vessel during injection of cold water

    International Nuclear Information System (INIS)

    Aya, Izuo; Kobayashi, Michiyuki; Inasaka, Fujio; Nariai, Hideki.

    1983-01-01

    The thermo-hydraulic behavior of saturated steam water mixture in a pressure vessel during injection of cold water was experimentally investigated with the Facility for Mixing Effect of Emergency Core Cooling Water. The dimensions of the pressure vessel used in the experiments were 284mm ID and 1,971mm height. 11 experiments were conducted without blowdown in order to comprehend the basic process excluding the effect of blowdown at injection of cold water. The initial pressure and water level, the injection flow rate and the size of injection nozzle were chosen as experimental parameters. Temperatures and void fractions at 6 elevations as well as pressure in the pressure vessel were measured, and new data especially on the pressure undershoot just after the initation of water injection and the vertical distribution of temperature and void fraction were gotten. The transients of pressure, average temperature and void fraction were caluculated using single-volume analysis code BLODAC-1V which is based on thermal equilibrium and so-called bubble gradient model. Some input parameters included in the analysis code were evaluated through the comparison of analysis with experimental data. Moreover, the observed pressure undershoot which is evaluated to be induced by a time lag of vapourization in water due to thermal nonequilibrium, was also discussed with the aid of another simple analysis model. (author)

  4. The hydraulics of the pressurized water reactors; L'hydraulique des reacteurs a eau pressurisee

    Energy Technology Data Exchange (ETDEWEB)

    Bouchter, J.C. [CEA Cadarache, SMET, 13 - Saint-Paul-lez-Durance (France); Barbier, D. [CEA/Grenoble, Dept. de Thermohydraulique et de Physique, DTP/SH2C, 38 (France); Caruso, A. [Electricite de France, Service Etudes et Projets Thermiques et Nucleaires, 75 - Paris (France)] [and others

    1999-07-02

    The SFEN organized, the 10 june 1999 at Paris, a meeting in the domain of the PWR hydraulics and in particular the hydraulic phenomena concerning the vessel and the vapor generators. The papers presented showed the importance of the industrial stakes with their associated phenomena: cores performance and safety with the more homogenous cooling system, the rods and the control rods wear, the temperature control, the fluid-structure interactions. A great part was also devoted to the progresses in the domain of the numerical simulation and the models and algorithms qualification. (A.L.B.)

  5. Thermal - hydraulic analysis of pressurizer water reactors using the model of open lateral boundary

    International Nuclear Information System (INIS)

    Borges, R.C.

    1980-10-01

    A computational method is developed for thermal-hydraulic analysis, where the channel may be analysed by more than one independent steps of calculation. This is made possible by the incorporation of the model of open lateral boundary in the code COBRA-IIIP, which permits the determination of the subchannel of an open lattice PWR core in a multi-step calculation. The thermal-hydraulic code COBRA-IIIP, developed at the Massachusetts Institute of Technology, is used as the basic model for this study. (Author) [pt

  6. Development and Applications of a General Coupled Thermal-hydraulic/Neutronic Model for the Ringhals-3 Pressurized Water Reactor

    International Nuclear Information System (INIS)

    Staalek, Mathias

    2008-03-01

    Coupled calculations are important for the simulation of nuclear power plants when there is a strong feedback between the neutron kinetics and the thermal-hydraulics. A general coupled model of the Ringhals-3 Pressurized Water Reactor has been developed for this purpose. The development is outlined in the thesis with details given in the appended papers. A PARCS model was developed for the core calculations and a RELAP5 model for the thermal-hydraulic calculations. The RELAP5 model has 157 channels for modelling the flow in the fuel assemblies. This means that there is a one-one correspondence radially between the neutronic and thermal-hydraulic nodalization. This detailed mapping between the neutron kinetics and the thermal-hydraulics makes it possible to use the model for all kinds of transient. To provide realistic material data to the PARCS model, a cross-section interface was developed. With this interface one can import material data from a binary CASMO-4 library file into PARCS. Due to the one-to-one mapping, any any core loading can easily be considered. The PARCS model was benchmarked against measurements of the steady-state power distribution of Ringhals-3. The power shape was well reproduced by the model. Validational work for steady-state conditions of the thermal-hydraulic was also successfully performed. The most challenging part of the validation of a coupled model is for transients. This is much more difficult since the dynamics of the system becomes very important. Two transients that occurred at Ringhals-3 were chosen for the validational work. The first transient was a Load Rejection Transient. In general the model gave good results but some problems were experienced, e.g. the pressurizer pressure turned out to be more difficult to be correctly simulated. The second transient was a Loss of Feed Water transient. A malfunctioning feed water control valve closed, and therefore shut down the feed water supply to the steam generator in one of the

  7. Development and Applications of a General Coupled Thermal-hydraulic/Neutronic Model for the Ringhals-3 Pressurized Water Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Staalek, Mathias

    2008-03-15

    Coupled calculations are important for the simulation of nuclear power plants when there is a strong feedback between the neutron kinetics and the thermal-hydraulics. A general coupled model of the Ringhals-3 Pressurized Water Reactor has been developed for this purpose. The development is outlined in the thesis with details given in the appended papers. A PARCS model was developed for the core calculations and a RELAP5 model for the thermal-hydraulic calculations. The RELAP5 model has 157 channels for modelling the flow in the fuel assemblies. This means that there is a one-one correspondence radially between the neutronic and thermal-hydraulic nodalization. This detailed mapping between the neutron kinetics and the thermal-hydraulics makes it possible to use the model for all kinds of transient. To provide realistic material data to the PARCS model, a cross-section interface was developed. With this interface one can import material data from a binary CASMO-4 library file into PARCS. Due to the one-to-one mapping, any any core loading can easily be considered. The PARCS model was benchmarked against measurements of the steady-state power distribution of Ringhals-3. The power shape was well reproduced by the model. Validational work for steady-state conditions of the thermal-hydraulic was also successfully performed. The most challenging part of the validation of a coupled model is for transients. This is much more difficult since the dynamics of the system becomes very important. Two transients that occurred at Ringhals-3 were chosen for the validational work. The first transient was a Load Rejection Transient. In general the model gave good results but some problems were experienced, e.g. the pressurizer pressure turned out to be more difficult to be correctly simulated. The second transient was a Loss of Feed Water transient. A malfunctioning feed water control valve closed, and therefore shut down the feed water supply to the steam generator in one of the

  8. GPU-Based Computation of Formation Pressure for Multistage Hydraulically Fractured Horizontal Wells in Tight Oil and Gas Reservoirs

    Directory of Open Access Journals (Sweden)

    Rongwang Yin

    2018-01-01

    Full Text Available A mathematical model for multistage hydraulically fractured horizontal wells (MFHWs in tight oil and gas reservoirs was derived by considering the variations in the permeability and porosity of tight oil and gas reservoirs that depend on formation pressure and mixed fluid properties and introducing the pseudo-pressure; analytical solutions were presented using the Newman superposition principle. The CPU-GPU asynchronous computing model was designed based on the CUDA platform, and the analytic solution was decomposed into infinite summation and integral forms for parallel computation. Implementation of this algorithm on an Intel i5 4590 CPU and NVIDIA GT 730 GPU demonstrates that computation speed increased by almost 80 times, which meets the requirement for real-time calculation of the formation pressure of MFHWs.

  9. Thermal hydraulic evaluation for an experimental facility to investigate pressurized thermal shock (PTS) in CDTN/CNEN

    International Nuclear Information System (INIS)

    Palmieri, Elcio T.; Navarro, Moyses A.; Aronne, Ivam D.; Terra, Jose L.

    2002-01-01

    The goal of the work presented in this paper is to provide necessary thermal hydraulics information to the design of an experimental installation to investigate the Pressurized Thermal Shock (PTS) to be implemented at Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN). The envisaged installation has a test section that represents, in a small scale, a pressure vessel of a nuclear reactor. This test section will be heated and then exposed to a PTS in order to evaluate the appearance and development of cracks. To verify the behavior of the temperatures of the pressure vessel after a sudden flood through the annulus, calculations were made using the RELAP5/MOD 3.2.2 gamma code. Different outer radiuses were studied for the annular region. The results showed that the smaller annulus spacing (20 mm) anticipates the wetting of the surface and produces a higher cooling of the external surface, which stays completely wet for a longer time. (author)

  10. Application study of fluid pressure energy recycling of decarbonisation process by C4H6O3 in ammonia synthesis systems by hydraulic turbochargers

    Science.gov (United States)

    Ji, Yunguang; Xu, Yangyang; Li, Hongtao; Oklejas, Michael; Xue, Shuqi

    2018-01-01

    A new type of hydraulic turbocharger energy recovery system was designed and applied in the decarbonisation process by propylene carbonate of a 100k tons ammonia synthesis system firstly in China. Compared with existing energy recovery devices, hydraulic turbocharger energy recovery system runs more smoothly, has lower failure rate, longer service life and greater comprehensive benefits due to its unique structure, simpler adjustment process and better adaptability to fluid fluctuation.

  11. Large-scale absence of sharks on reefs in the greater-Caribbean: a footprint of human pressures.

    Science.gov (United States)

    Ward-Paige, Christine A; Mora, Camilo; Lotze, Heike K; Pattengill-Semmens, Christy; McClenachan, Loren; Arias-Castro, Ery; Myers, Ransom A

    2010-08-05

    In recent decades, large pelagic and coastal shark populations have declined dramatically with increased fishing; however, the status of sharks in other systems such as coral reefs remains largely unassessed despite a long history of exploitation. Here we explore the contemporary distribution and sighting frequency of sharks on reefs in the greater-Caribbean and assess the possible role of human pressures on observed patterns. We analyzed 76,340 underwater surveys carried out by trained volunteer divers between 1993 and 2008. Surveys were grouped within one km2 cells, which allowed us to determine the contemporary geographical distribution and sighting frequency of sharks. Sighting frequency was calculated as the ratio of surveys with sharks to the total number of surveys in each cell. We compared sighting frequency to the number of people in the cell vicinity and used population viability analyses to assess the effects of exploitation on population trends. Sharks, with the exception of nurse sharks occurred mainly in areas with very low human population or strong fishing regulations and marine conservation. Population viability analysis suggests that exploitation alone could explain the large-scale absence; however, this pattern is likely to be exacerbated by additional anthropogenic stressors, such as pollution and habitat degradation, that also correlate with human population. Human pressures in coastal zones have lead to the broad-scale absence of sharks on reefs in the greater-Caribbean. Preventing further loss of sharks requires urgent management measures to curb fishing mortality and to mitigate other anthropogenic stressors to protect sites where sharks still exist. The fact that sharks still occur in some densely populated areas where strong fishing regulations are in place indicates the possibility of success and encourages the implementation of conservation measures.

  12. Large-scale absence of sharks on reefs in the greater-Caribbean: a footprint of human pressures.

    Directory of Open Access Journals (Sweden)

    Christine A Ward-Paige

    Full Text Available BACKGROUND: In recent decades, large pelagic and coastal shark populations have declined dramatically with increased fishing; however, the status of sharks in other systems such as coral reefs remains largely unassessed despite a long history of exploitation. Here we explore the contemporary distribution and sighting frequency of sharks on reefs in the greater-Caribbean and assess the possible role of human pressures on observed patterns. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed 76,340 underwater surveys carried out by trained volunteer divers between 1993 and 2008. Surveys were grouped within one km2 cells, which allowed us to determine the contemporary geographical distribution and sighting frequency of sharks. Sighting frequency was calculated as the ratio of surveys with sharks to the total number of surveys in each cell. We compared sighting frequency to the number of people in the cell vicinity and used population viability analyses to assess the effects of exploitation on population trends. Sharks, with the exception of nurse sharks occurred mainly in areas with very low human population or strong fishing regulations and marine conservation. Population viability analysis suggests that exploitation alone could explain the large-scale absence; however, this pattern is likely to be exacerbated by additional anthropogenic stressors, such as pollution and habitat degradation, that also correlate with human population. CONCLUSIONS/SIGNIFICANCE: Human pressures in coastal zones have lead to the broad-scale absence of sharks on reefs in the greater-Caribbean. Preventing further loss of sharks requires urgent management measures to curb fishing mortality and to mitigate other anthropogenic stressors to protect sites where sharks still exist. The fact that sharks still occur in some densely populated areas where strong fishing regulations are in place indicates the possibility of success and encourages the implementation of conservation measures.

  13. Control system for the feed of pressurized fluid in a hydraulic circuit as a function of the state of the locking or unlocking of two mechanical organs

    International Nuclear Information System (INIS)

    Huet, Y.; Perichon, C.

    1985-01-01

    The control system comprises two hydraulic cylinders of which rods are integral with the mechanical organs. The piston of the first cylinder separates the chamber of this one in two parts. The piston of the second cylinder separates its chamber in three parts. The inlet chamber of the two cylinders are connected to pressurized fluid feed pipes, and the outlet chambers to a depressurization pipe. According to the position of the piston depending itself on the state of locking or unlocking of the rods, an interconnection pipe and a feed pipe of the pressurized fluid hydraulic circuit communicate with a chamber or another one. The feed of the hydraulic circuit is possible only the two rods are unlocked. The invention applies more particularly to the feed of the control circuit of an emergency seal of the primary pump of a pressurized water nuclear reactor [fr

  14. PTA-1 computer program for treating pressure transients in hydraulic networks including the effect of pipe plasticity

    International Nuclear Information System (INIS)

    Youngdahl, C.K.; Kot, C.A.

    1977-01-01

    Pressure pulses in the intermediate sodium system of a liquid-metal-cooled fast breeder reactor, such as may originate from a sodium/water reaction in a steam generator, are propagated through the complex sodium piping network to system components such as the pump and intermediate heat exchanger. To assess the effects of such pulses on continued reliable operation of these components and to contribute to system designs which result in the mitigation of these effects, Pressure Transient Analysis (PTA) computer codes are being developed for accurately computing the transmission of pressure pulses through a complicated fluid transport system, consisting of piping, fittings and junctions, and components. PTA-1 provides an extension of the well-accepted and verified fluid hammer formulation for computing hydraulic transients in elastic or rigid piping systems to include plastic deformation effects. The accuracy of the modeling of pipe plasticity effects on transient propagation has been validated using results from two sets of Stanford Research Institute experiments. Validation of PTA-1 using the latter set of experiments is described briefly. The comparisons of PTA-1 computations with experiments show that (1) elastic-plastic deformation of LMFBR-type piping can have a significant qualitative and quantitative effect on pressure pulse propagation, even in simple systems; (2) classical fluid-hammer theory gives erroneous results when applied to situations where piping deforms plastically; and (3) the computational model incorporated in PTA-1 for predicting plastic deformation and its effect on transient propagation is accurate

  15. Thermal-hydraulic calculations for a fuel assembly in a European Pressurized Reactor using the RELAP5 code

    Directory of Open Access Journals (Sweden)

    Skrzypek Maciej

    2015-09-01

    Full Text Available The main object of interest was a typical fuel assembly, which constitutes a core of the nuclear reactor. The aim of the paper is to describe the phenomena and calculate thermal-hydraulic characteristic parameters in the fuel assembly for a European Pressurized Reactor (EPR. To perform thermal-hydraulic calculations, the RELAP5 code was used. This code allows to simulate steady and transient states for reactor applications. It is also an appropriate calculation tool in the event of a loss-of-coolant accident in light water reactors. The fuel assembly model with nodalization in the RELAP5 (Reactor Excursion and Leak Analysis Program code was presented. The calculations of two steady states for the fuel assembly were performed: the nominal steady-state conditions and the coolant flow rate decreased to 60% of the nominal EPR flow rate. The calculation for one transient state for a linearly decreasing flow rate of coolant was simulated until a new level was stabilized and SCRAM occurred. To check the correctness of the obtained results, the authors compared them against the reactor technical documentation available in the bibliography. The obtained results concerning steady states nearly match the design data. The hypothetical transient showed the importance of the need for correct cooling in the reactor during occurrences exceeding normal operation. The performed analysis indicated consequences of the coolant flow rate limitations during the reactor operation.

  16. Computer code for thermal-hydraulic simulation of heat pressurizer tanks operation (Simterm-H)

    International Nuclear Information System (INIS)

    Sellos, R.F.

    1987-01-01

    It is presented the Simtherm-H computer code, developed for calculating the thermodynamic properties of the high pressure heating system and the feedwater tank in transient state for PWR nuclear power plants (1300 MWe). (E.G.) [pt

  17. Hydraulic fracture considerations in oil sand overburden dams

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, R.; Madden, B.; Danku, M. [Syncrude Canada Ltd., Fort McMurray, AB (Canada)

    2008-07-01

    This paper discussed hydraulic fracture potential in the dry-filled temporary dams used in the oil sands industry. Hydraulic fractures can occur when reservoir fluid pressures are greater than the minimum stresses in a dam. Stress and strain conditions are influenced by pore pressures, levels of compaction in adjacent fills as well as by underlying pit floor and abutment conditions. Propagation pressure and crack initiation pressures must also be considered in order to provide improved hydraulic fracture protection to dams. Hydraulic fractures typically result in piping failures. Three cases of hydraulic fracture at oil sands operations in Alberta were presented. The study showed that hydraulic fracture failure modes must be considered in dam designs, particularly when thin compacted lift of dry fill are used to replace wetted clay cores. The risk of hydraulic fractures can be reduced by eliminating in situ bedrock irregularities and abutments. Overpressure heights, abutment sloping, and the sloping of fills above abutments, as well as the dam's width and base conditions must also be considered in relation to potential hydraulic fractures. It was concluded that upstream sand beaches and internal filters can help to prevent hydraulic fractures in dams in compacted control zones. 5 refs., 16 figs.

  18. Hydraulic performance evaluation of pressure compensating (pc) emitters and micro-tubing for drip irrigation system

    International Nuclear Information System (INIS)

    Mangrio, A.G.; Asif, M.; Jahangir, I.

    2013-01-01

    Drip irrigation system is necessary for those areas, where the water scarcity issues are present. The present study was conducted at the field station of Climate Change, Alternate Energy and Water Resources Institute (CAEWRI), National Agricultural Research Center (NARC), Islamabad, during 2013, regarding drip irrigation system. Drip irrigation system depends on uniform emitter application flow. All the emitters were tested and replicated thrice at pressure head (34 to 207Kpa) with an increment of 34 Kpa. The minimum and maximum discharges were 1.32 - 3.52, 3.36 - 5.42, and 43.22 - 100.99 Lph, with an average of 2.42, 4.63 and 73.66 Lph, for Bow Smith, RIS and Micro-tubing, respectively. It indicates that more than 90% of emission uniformity (EU) and uniformity coefficient (CU) for all Emitters, which shows excellent water application with least standard deviation, ranging 0.12 to 2.37, throughout the operating pressure heads in all emitters. An average coefficient of variation (CV) of all emitters were behaving less than 0.07, indicating an excellent class at all operating pressure heads between 34 to 207 Kpa. Moreover, the relationship of discharge and pressure of emitters indicates that discharge increased with the increase of pressure head. The Q-H curve plays key role in the selection of emitters. (author)

  19. Development of the pressure-time method as a relative and absolute method for low-head hydraulic machines

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Pontus [Poeyry SwedPower AB, Stockholm (Sweden); Cervantes, Michel [Luleaa Univ. of Technology, Luleaa (Sweden)

    2013-02-15

    The pressure-time method is an absolute method common for flow measurements in power plants. The method determines the flow rate by measuring the pressure and estimating the losses between two sections in the penstock during a closure of the guide vanes. The method has limitations according to the IEC41 standard, which makes it difficult to use at Swedish plants where the head is generally low. This means that there is limited experience/knowledge in Sweden on this method, where the Winter-Kennedy is usually used. Since several years, Luleaa University of Technology works actively in the development of the pressure-time method for low-head hydraulic machines with encouraging results. Focus has been in decreasing the distance between both measuring sections and evaluation of the viscous losses. Measurements were performed on a pipe test rig (D=0.3 m) in a laboratory under well controlled conditions with 7pressure-time measurements (with L=5 m) performed on a 10 MW Kaplan turbine compared to transit-time flow measurements. The new formulation taking into account the unsteady losses allows a better estimation of the flow rate, up to 0.3%. As an alternative to the Winter-Kennedy widely used in Sweden, the pressure-time method was tested as a relative method by measuring the pressure between the free surface and a section in the penstock without knowing the exact geometry, i.e., pipe factor. Such measurements may be simple to perform as most of the inlet spiral casings have pressure taps. Furthermore, the viscous losses do not need to be accurately determined as long as they are handled similarly between the measurements. The pressure-time method may thus become an alternative to the Winter-Kennedy.

  20. RELAP5 thermal-hydraulic analyses of overcooling sequences in a pressurized water reactor

    International Nuclear Information System (INIS)

    Bolander, M.A.; Fletcher, C.D.; Davis, C.B.; Kullberg, C.M.; Stitt, B.D.; Waterman, M.E.; Burtt, J.D.

    1984-01-01

    In support of the Pressurized Thermal Shock Integration Study, sponsored by the United States Nuclear Regulatory Commission, the Idaho National Engineering Laboratory has performed analyses of overcooling transients using the RELAP5/MOD1.6 and MOD2.0 computer codes. These analyses were performed for the H.B. Robinson Unit 2 pressurized water reactor, which is a Westinghouse 3-loop design plant. Results of the RELAP5 analyses are presented. The capabilities of the RELAP5 computer code as a tool for analyzing integral plant transients requiring a detailed plant model, including complex trip logic and major control systems, are examined

  1. A low hydraulic capacitance pressure sensor for integration with a micro viscosity detector

    NARCIS (Netherlands)

    van der Heyden, F.H.J.; Blom, M.T.; Gardeniers, Johannes G.E.; Chmela, E.; Elwenspoek, Michael Curt; Tijssen, R.P; van den Berg, Albert

    2003-01-01

    A design is presented for a micromachined differential viscometer, that is suitable for integration into a planar hydrodynamic chromatography system (HDC) for polymer analysis. The viscometer consists of four equal flow restrictions and two pressure sensors, connected in a Wheatstone bridge

  2. The impact of hydraulic flow unit & reservoir quality index on pressure profile and productivity index in multi-segments reservoirs

    Directory of Open Access Journals (Sweden)

    Salam Al-Rbeawi

    2017-12-01

    Full Text Available The objective of this paper is studying the impact of the hydraulic flow unit and reservoir quality index (RQI on pressure profile and productivity index of horizontal wells acting in finite reservoirs. Several mathematical models have been developed to investigate this impact. These models have been built based on the pressure distribution in porous media, depleted by a horizontal well, consist of multi hydraulic flow units and different reservoir quality index. The porous media are assumed to be finite rectangular reservoirs having different configurations and the wellbores may have different lengths. Several analytical models describing flow regimes have been derived wherein hydraulic flow units and reservoir quality index have been included in addition to rock and fluid properties. The impact of these two parameters on reservoir performance has also been studied using steady state productivity index.It has been found that both pressure responses and flow regimes are highly affected by the existence of multiple hydraulic flow units in the porous media and the change in reservoir quality index for these units. Positive change in the RQI could lead to positive change in both pressure drop required for reservoir fluids to move towards the wellbore and hence the productivity index.

  3. Atmospheric-pressure small-scale thermal-hydraulic experiment of a PIUS-type reactor

    International Nuclear Information System (INIS)

    Tasaka, Kanji; Tamaki, Masayoshi; Imai, Satoshi; Kohketsu, Hideto; Anoda, Yoshinari; Murata, Hideo; Kukita, Yutaka.

    1992-01-01

    An experimental small-scale low-pressure setup of a PIUS (Process Inherent Ultimate Safety)-type reactor was used for the examination of the stability during normal operation such as startup and load following operation and of the safety during accidents such as loss-of-feedwater and pump runaway. Automatic feedback pump control system based on differential pressure at lower honeycomb density lock was quite effective to maintain the stratified interface between primary and pool water in the honeycomb density lock during normal operation. The process inherent ultimate safety characteristics of the PIUS-type reactor was confirmed with pump-trip scram at the pump speed limit for the various simulated accidents such as a loss-of-feedwater and pump runaway. (author)

  4. Mitigation of pressure fluctuations in the discharge cone of hydraulic turbines using flow-feedback

    International Nuclear Information System (INIS)

    Tanasa, C; Susan-Resiga, R; Bosioc, A; Muntean, S

    2010-01-01

    Our previous experimental and numerical investigations of decelerated swirling flows in conical diffusers have demonstrated that water jet injection along the symmetry axis mitigates the pressure fluctuations associated with the precessing vortex rope. However, for swirling flows similar to Francis turbines operated at partial discharge, the jet becomes effective when the jet discharge is larger than 10% from the turbine discharge, leading to large volumetric losses when the jet is supplied from upstream the runner. As a result, we introduce in this paper a new approach for supplying the jet by using a fraction of the discharge collected downstream the conical diffuser. We present the technical implementation of this flow-feedback approach, and we investigated experimentally its capability in mitigating the pressure fluctuations generated by the precessing vortex rope. The main advantage of this flow-feedback approach is that is does not require additional energy to supply the jet and it does not decrease the turbine efficiency.

  5. Analysis of thermo-hydraulic behavior of coolant during discharge of pressurized high-temperature water

    International Nuclear Information System (INIS)

    Suzuki, Mitsuhiro; Sobajima, Makoto; Sasaki, Shinobu; Onishi, Nobuaki; Shiba, Masayoshi

    1978-01-01

    The present report describes results of the analysis of the LOFT semiscale experiment No. 1011 using remodeled RELAP-3 code, performed at the Idaho National Engineering Laboratory to simulate a postulated loss-of-coolant accident in a pressurized water reactor. It was clarified through the analysis that coolant behavior during blowdown was influenced variously by the system components in the primary loop, comparing with coolant discharge from a pressure vessel. Good agreement was obtained between experimental and analytical results when phase separation was assumed in upper plenum and downcomer, since experimental data indicated existence of liquid level in those parts. It was also found that the use of the Wilson's equation to calculate bubble rise velocity and the use of discharge coefficient as the function of fluid quality at break location to calculate discharge flow rate resulted in good agreement with experimental data. (auth.)

  6. Low-pressure hydraulic technique for slurrying radioactive sludges in waste tanks

    International Nuclear Information System (INIS)

    Bradley, R.F.; Parsons, F.A.; Goodlett, C.B.; Mobley, R.M.

    1977-11-01

    Present technology for the removal of sludges from radioactive liquid waste storage tanks at the Savannah River Plant (SRP) requires large volumes of fresh water added through high-pressure (approx.3000 psig) nozzles positioned to resuspend and slurry the sludge. To eliminate the cost of storing and evaporating these large volumes of water (several hundred thousand gallons per tank cleaned), a technique was developed at the Savannah River Laboratory (SRL) to use recirculating, radioactive, supernate solution to resuspend the sludge. The system consists in part of a single-stage centrifugal pump operating in the sludge at approx.100 psia. Recirculating supernate is drawn into the bottom of the pump and forced out through two oppositely directed nozzles to give liquid jets with a sludge-slurrying capability equal to that obtained with the present high-pressure system. In addition to eliminating the addition of large quantities of water to the tanks, the low-pressure recirculating technique requires only approximately one-sixth of the power required by the high-pressure system. Test results with clay (as a simulant for sludge) in a waste tank mockup confirmed theoretical predictions that jets with the same momentum gave essentially the same sludge-slurrying patterns. The effective cleaning radius of the recirculating jet was directly proportional to the product of the nozzle velocity and the nozzle diameter (U 0 D). At the maximum U 0 D developed by the pump (approx.14 ft 2 /s), the effective cleaning radius in the tank mockup was approx.20 feet

  7. Thermal-hydraulic behaviors of vapor-liquid interface due to arrival of a pressure wave

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Akira; Fujii, Yoshifumi; Matsuzaki, Mitsuo [Tokyo Institute of Technology (Japan)

    1995-09-01

    In the vapor explosion, a pressure wave (shock wave) plays a fundamental role for triggering, propagation and enhancement of the explosion. Energy of the explosion is related to the magnitude of heat transfer rate from hot liquid to cold volatile one. This is related to an increasing rate of interface area and to an amount of transient heat flux between the liquids. In this study, the characteristics of transient heat transfer and behaviors of vapor film both on the platinum tube and on the hot melt tin drop, under same boundary conditions have been investigated. It is considered that there exists a fundamental mechanism of the explosion in the initial expansion process of the hot liquid drop immediately after arrival of pressure wave. The growth rate of the vapor film is much faster on the hot liquid than that on the solid surface. Two kinds of roughness were observed, one due to the Taylor instability, by rapid growth of the explosion bubble, and another, nucleation sites were observed at the vapor-liquid interface. Based on detailed observation of early stage interface behaviors after arrival of a pressure wave, the thermal fragmentation mechanism is proposed.

  8. SATCAP-C : a program for thermal hydraulic design of pressurized water injection type capsule

    International Nuclear Information System (INIS)

    Harayama, Yasuo; Someya, Hiroyuki; Asoh, Tomokazu; Niimi, Motoji

    1992-10-01

    There are capsules called 'Pressure Water Injection Type Capsule' as a kind of irradiation devices at the Japan Materials Testing Reactor (JMTR). A type of the capsules is a 'Boiling Water Capsule' (usually named BOCA). The other type is a 'Saturated Temperature Capsule' (named SATCAP). When the water is kept at a constant pressure, the water temperature does not become higher than the saturated temperature so far as the water does not fully change to steam. These type capsules are designed on the basis of the conception of applying the water characteristic to the control of irradiation temperature of specimens in the capsules. In designing of the capsules in which the pressurized water is injected, thermal performances have to be understood as exactly as possible. It is not easy however to predict thermal performances such as axially temperature distribution of water injected in the capsule, because there are heat-sinks at both side of inner and outer of capsule casing as the result that the water is fluid. Then, a program (named SATCAP-C) for the BOCA and SATCAP was compiled to grasp the thermal performances in the capsules and has been used the design of the capsules and analysis of the data obtained from some actual irradiation capsules. It was confirmed that the program was effective in thermal analysis for the capsules. The analysis found out the values for heat transfer coefficients at various surfaces of capsule components and some thermal characteristics of capsules. (author)

  9. Hydrogeology, hydraulic characteristics, and water-quality conditions in the surficial, Castle Hayne and Peedee aquifers of the greater New Hanover County area, North Carolina, 2012-13

    Science.gov (United States)

    McSwain, Kristen Bukowski; Gurley, Laura N.; Antolino, Dominick J.

    2014-01-01

    A major issue facing the greater New Hanover County, North Carolina, area is the increased demand for drinking water resources as a result of rapid growth. The principal sources of freshwater supply in the greater New Hanover County area are withdrawals of surface water from the Cape Fear River and groundwater from the underlying Castle Hayne and Peedee aquifers. Industrial, mining, irrigation, and aquaculture groundwater withdrawals increasingly compete with public-supply utilities for freshwater resources. Future population growth and economic expansion will require increased dependence on high-quality sources of fresh groundwater. An evaluation of the hydrogeology and water-quality conditions in the surficial, Castle Hayne, and Peedee aquifers was conducted in New Hanover, eastern Brunswick, and southern Pender Counties, North Carolina. A hydrogeologic framework was delineated by using a description of the geologic and hydrogeologic units that compose aquifers and their confining units. Current and historic water-level, water-quality, and water-isotope data were used to approximate the present boundary between freshwater and brackish water in the study area. Water-level data collected during August–September 2012 and March 2013 in the Castle Hayne aquifer show that recharge areas with the highest groundwater altitudes are located in central New Hanover County, and the lowest are located in a discharge area along the Atlantic Ocean. Between 1964 and 2012, groundwater levels in the Castle Hayne aquifer in central New Hanover County have rebounded by about 10 feet, but in the Pages Creek area groundwater levels declined in excess of 20 feet. In the Peedee aquifer, the August–September 2012 groundwater levels were affected by industrial withdrawals in north-central New Hanover County. Groundwater levels in the Peedee aquifer declined more than 20 feet between 1964 and 2012 in northeastern New Hanover County because of increased withdrawals. Vertical gradients

  10. The effect of vapour pressure deficit on stomatal conductance, sap pH and leaf-specific hydraulic conductance in Eucalyptus globulus clones grown under two watering regimes.

    Science.gov (United States)

    Hernandez, Maria Jose; Montes, Fernando; Ruiz, Federico; Lopez, Gustavo; Pita, Pilar

    2016-05-01

    Stomatal conductance has long been considered of key interest in the study of plant adaptation to water stress. The expected increase in extreme meteorological events under a climate change scenario may compromise survival in Eucalyptus globulus plantations established in south-western Spain. We investigated to what extent changes in stomatal conductance in response to high vapour pressure deficits and water shortage are mediated by hydraulic and chemical signals in greenhouse-grown E. globulus clones. Rooted cuttings were grown in pots and submitted to two watering regimes. Stomatal conductance, shoot water potential, sap pH and hydraulic conductance were measured consecutively in each plant over 4 weeks under vapour pressure deficits ranging 0·42 to 2·25 kPa. Evapotranspiration, growth in leaf area and shoot biomass were also determined. There was a significant effect of both clone and watering regime in stomatal conductance and leaf-specific hydraulic conductance, but not in sap pH. Sap pH decreased as water potential and stomatal conductance decreased under increasing vapour pressure deficit. There was no significant relationship between stomatal conductance and leaf-specific hydraulic conductance. Stomata closure precluded shoot water potential from falling below -1·8 MPa. The percentage loss of hydraulic conductance ranged from 40 to 85 %. The highest and lowest leaf-specific hydraulic conductances were measured in clones from the same half-sib families. Water shortage reduced growth and evapotranspiration, decreases in evapotranspiration ranging from 14 to 32 % in the five clones tested. Changes in sap pH seemed to be a response to changes in atmospheric conditions rather than soil water in the species. Stomata closed after a considerable amount of hydraulic conductance was lost, although intraspecific differences in leaf-specific hydraulic conductance suggest the possibility of selection for improved productivity under water-limiting conditions

  11. Thermal-hydraulic instabilities in pressure tube graphite - moderated boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Tsiklauri, G.; Schmitt, B.

    1995-09-01

    Thermally induced two-phase instabilities in non-uniformly heated boiling channels in RBMK-1000 reactor have been analyzed using RELAP5/MOD3 code. The RELAP5 model of a RBMK-1000 reactor was developed to investigate low flow in a distribution group header (DGH) supplying 44 fuel pressure tubes. The model was evaluated against experimental data. The results of the calculations indicate that the period of oscillation for the high power tube varied from 3.1s to 2.6s, over the power range of 2.0 MW to 3.0 MW, respectively. The amplitude of the flow oscillation for the high powered tube varied from +100% to -150% of the tube average flow. Reverse flow did not occur in the lower power tubes. The amplitude of oscillation in the subcooled region at the inlet to the fuel region is higher than in the saturated region at the outlet. In the upper fuel region and outlet connectors the flow oscillations are dissipated. The threshold of flow instability for the high powered tubes of a RBMK reactor is compared to Japanese data and appears to be in good agreement.

  12. Thermal-hydraulic instabilities in pressure tube graphite-moderated boiling water reactors

    International Nuclear Information System (INIS)

    Tsiklauri, G.; Schmitt, B.

    1995-09-01

    Thermally induced two-phase instabilities in non-uniformly heated boiling charmers in RBMK-1000 reactor have been analyzed using RELAP5/MOD3 code. The RELAP5 model of a RBMK-1000 reactor was developed to investigate low flow in a distribution group header (DGH) supplying 44 fuel pressure tubes. The model was evaluated against experimental data. The results of the calculations indicate that the period of oscillation for the high power tube varied from 3.1s to 2.6s, over the power range of 2.0 MW to 3.0 MW, respectively. The amplitude of the flow oscillation for the high powered tube varied from +100% to -150% of the tube average flow. Reverse flow did not occur in the lower power tubes. The amplitude of oscillation in the subcooled region at the inlet to the fuel region is higher than in the saturated region at the outlet. In the upper fuel region and outlet connectors the flow oscillations are dissipated. The threshold of flow instability for the high powered tubes of a RBMK reactor is compared to Japanese data and appears to be in good agreement

  13. Influence of Pressure Build-Up Time of Compression Chamber on Improving the Operation Frequency of a Single-Piston Hydraulic Free-Piston Engine

    Directory of Open Access Journals (Sweden)

    Hai-bo Xie

    2013-01-01

    Full Text Available A single-piston hydraulic free-piston engine with a two-cylinder four-stroke diesel engine as its driver is introduced. It takes the free-piston assembly a certain time to move after the pressure in the compression chamber starts to increase. The time difference between the pressure increasing and the piston starting to move is defined as the pressure build-up time. The characteristics of the pressure build-up time and its influence on the performance of the free-piston engine are introduced and analyzed. Based on the basic law of dynamics of the free-piston assembly, the parameters which influence the pressure build-up time are analyzed. And then improvement and optimization are proposed to shorten the pressure build-up time.

  14. 3D Numerical Simulation versus Experimental Assessment of Pressure Pulsations Using a Passive Method for Swirling Flow Control in Conical Diffusers of Hydraulic Turbines

    Science.gov (United States)

    TANASA, C.; MUNTEAN, S.; CIOCAN, T.; SUSAN-RESIGA, R. F.

    2016-11-01

    The hydraulic turbines operated at partial discharge (especially hydraulic turbines with fixed blades, i.e. Francis turbine), developing a swirling flow in the conical diffuser of draft tube. As a result, the helical vortex breakdown, also known in the literature as “precessing vortex rope” is developed. A passive method to mitigate the pressure pulsations associated to the vortex rope in the draft tube cone of hydraulic turbines is presented in this paper. The method involves the development of a progressive and controlled throttling (shutter), of the flow cross section at the bottom of the conical diffuser. The adjustable cross section is made on the basis of the shutter-opening of circular diaphragms, while maintaining in all positions the circular cross-sectional shape, centred on the axis of the turbine. The stagnant region and the pressure pulsations associated to the vortex rope are mitigated when it is controlled with the turbine operating regime. Consequently, the severe flow deceleration and corresponding central stagnant are diminished with an efficient mitigation of the precessing helical vortex. Four cases (one without diaphragm and three with diaphragm), are numerically and experimentally investigated, respectively. The present paper focuses on a 3D turbulent swirling flow simulation in order to evaluate the control method. Numerical results are compared against measured pressure recovery coefficient and Fourier spectra. The results prove the vortex rope mitigation and its associated pressure pulsations when employing the diaphragm.

  15. Application of RELAP5/MOD3.3 to Calculate Thermal Hydraulic Behavior of the Pressurizer Safety Valve Performance Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Hyun; Kim, Young Ae; Oh, Seung Jong; Park, Jong Woon [Korea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of)

    2007-10-15

    The increase of the acceptance tolerance of Pressurizer Safety Valve (PSV) test is vital for the safe operation of nuclear power plants because the frequent tests may make the valves decrepit and become a cause of leak. Recently, Korea Hydro and Nuclear Power Company (KHNP) is building a PSV performance test facility to provide the technical background data for the relaxation of the acceptance tolerance of PSV including the valve pop-up characteristics and the loop seal dynamics (if the plant has the loop seal in the upstream of PSV). The discharge piping and supports must be designed to withstand severe transient hydrodynamic loads when the safety valve actuates. The evaluation of hydrodynamic loads is a two-step process: first the thermal hydraulic behavior in the piping must be defined, and then the hydrodynamic loads are calculated from the thermal hydraulic parameters such as pressure and mass flow. The hydrodynamic loads are used as input to the structural analysis.

  16. Effects of turbine's selection on hydraulic transients in the long pressurized water conveyance system

    International Nuclear Information System (INIS)

    Zhou, J X; Hu, M; Cai, F L; Huang, X T

    2014-01-01

    For a hydropower station with longer water conveyance system, an optimum turbine's selection will be beneficial to its reliable and stable operation. Different optional turbines will result in possible differences of the hydraulic characteristics in the hydromechanical system, and have different effects on the hydraulic transients' analysis and control. Therefore, the premise for turbine's selection is to fully understand the properties of the optional turbines and their effects on the hydraulic transients. After a brief introduction of the simulation models for hydraulic transients' computation and stability analysis, the effects of hydraulic turbine's characteristics at different operating points on the hydro-mechanical system's free vibration analysis were theoretically investigated with the hydraulic impedance analysis of the hydraulic turbine. For a hydropower station with long water conveyance system, based on the detailed hydraulic transients' computation respectively for two different optional turbines, the effects of the turbine's selection on hydraulic transients were analyzed. Furthermore, considering different operating conditions for each turbine and the similar operating conditions for these two turbines, free vibration analysis was comprehensively carried out to reveal the effects of turbine's impedance on system's vibration characteristics. The results indicate that, respectively with two different turbines, most of the controlling parameters under the worst cases have marginal difference, and few shows obvious differences; the turbine's impedances under different operating conditions have less effect on the natural angular frequencies; different turbine's characteristics and different operating points have obvious effects on system's vibration stability; for the similar operating conditions of these two turbines, system's vibration characteristics are basically consistent with

  17. Does greater adiposity increase blood pressure and hypertension risk?: Mendelian randomization using the FTO/MC4R genotype

    DEFF Research Database (Denmark)

    Timpson, Nicholas J; Harbord, Roger; Davey Smith, George

    2009-01-01

    of the causal association between body mass index and blood pressure. This was performed using both rs9939609 (FTO) and rs17782313 (MC4R) genotypes as instruments for body mass index. Avoiding the epidemiological problems of confounding, bias, and reverse causation, we confirmed observational associations...

  18. Combined Permeability Improvement Technology of High-pressure Hydraulic Slotting with Hydraulic Fracturing and Its Application%高压水力割缝和压裂联合增透技术及应用

    Institute of Scientific and Technical Information of China (English)

    秦江涛; 陈玉涛

    2016-01-01

    针对白皎煤矿突出煤层构造应力高、透气性系数低、瓦斯抽采效果差等问题,在238底板瓦斯抽采巷对B4煤层采用了水力割缝和压裂联合增透技术,应用结果表明该技术相比水力压裂技术和普通抽采技术提高了煤层透气性,瓦斯抽采纯量较水力压裂钻孔提高了1.33倍,瓦斯体积分数是普通抽采钻孔的2.76倍,联合增透钻孔汇总瓦斯体积分数保持在30%以上且无衰减,具有良好的抽采效果.%To counter the problems of high structural stress, low air permeability coefficient and poor gas drainage effect of the outburst coal seam in Baijiao Mine, the gas drainage test in B4 seam by 238 floor drainage roadway was carried out with the combined permeability improvement technology of high-pressure hydraulic slotting with hydraulic fracturing. The application results showed that this technology improved the permeability of the coal seam as compared to the hydraulic fracturing technology and the conventional gas drainage technology. The pure gas drainage volume increased 1. 33 times to that by hydraulic fracturing, the volume fraction of gas was 2. 76 times higher than that by the conventional drainage boreholes, the summary volume fraction of gas with the combined permeability improvement technology maintained over 30% without any attenuation, so this technology has good drainage effect.

  19. Hydraulic design of Three Gorges right bank powerhouse turbine for improvement of hydraulic stability

    International Nuclear Information System (INIS)

    Shi, Q

    2010-01-01

    This paper presents the hydraulic design of Three Gorges Right Bank Powerhouse turbine for improvement of hydraulic stability. The technical challenges faced in the hydraulic design of the turbine are given. The method of hydraulic design for improving the hydraulic stability and particularly for eliminating the upper part load pressure pulsations is clarified. The final hydraulic design results of Three Gorges Right Bank Powerhouse turbine based on modern hydraulic design techniques are presented.

  20. Hydraulic design of Three Gorges right bank powerhouse turbine for improvement of hydraulic stability

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Q, E-mail: qhshi@dfem.com.c [Dong Fang Electrical Machinery Co., Ltd., DEC 188, Huanghe West Road, Deyang, 618000 (China)

    2010-08-15

    This paper presents the hydraulic design of Three Gorges Right Bank Powerhouse turbine for improvement of hydraulic stability. The technical challenges faced in the hydraulic design of the turbine are given. The method of hydraulic design for improving the hydraulic stability and particularly for eliminating the upper part load pressure pulsations is clarified. The final hydraulic design results of Three Gorges Right Bank Powerhouse turbine based on modern hydraulic design techniques are presented.

  1. Central Pulsatile Pressure and Flow Relationship in the Time and Frequency Domain to Characterise Hydraulic Input to the Brain and Cerebral Vascular Impedance.

    Science.gov (United States)

    Kim, Mi Ok; O'Rourke, Michael F; Adji, Audrey; Avolio, Alberto P

    2016-01-01

    In the time domain, pulsatile flow and pressure can be characterised as the ratio of the late systolic boost of flow or pressure to the pulse amplitude so as to estimate the hydraulic input to the brain. While vascular impedance has been widely used to represent the load presented to the heart by the systemic circulation, it has not been applied to the cerebral circulation.We set out to study the relationship between the pressure and the flow augmentation index (AIx) in the time domain and to determine cerebral vascular impedance using aortic blood pressure and cerebral blood flow waveforms in the frequency domain. Twenty-four young subjects (aged 21-39 years) were recruited; aortic pressure was derived using SphygmoCor from radial pressure. Flow waveforms were recorded from the middle cerebral artery. In three subjects, we performed the Valsalva manoeuvre to investigate their response to physiological intervention. There was a linear relationship between flow and pressure AIx, and cerebral impedance values were similar to those estimated for low resistance vascular beds. Substantial change in pressure and flow wave contour was observed during the Valsalva manoeuvre; however, the relationship in both the time and the frequency domains were unchanged. This confirms that aortic pressure and cerebral flow waveform can be used to study cerebral impedance.

  2. Standardization of the methodology used for fuel pressure drop evaluation to improve hydraulic calculation of heterogeneous cores

    International Nuclear Information System (INIS)

    Le Borgne, E.; Mattei, A.; Rome, M.; Rodriguez, J.M.

    2004-01-01

    The determination of hydraulic characteristics for fuel subassembly components is dependent on the hypotheses and the methodology considered. The results of hydraulic compatibility calculations using input data from different sources may thus be difficult to analyse, and their reliability will consequently be reduced. Electricite de France (EDF) and Commissariat a l'Energie Atomique (CEA) have initiated a common program aiming at controlling the consequences of such a situation, increasing the reliability of the values used in the hydraulic compatibility calculations, and proposing a standardization of the operating procedures. In a first step, this program is based on the measurements performed in the CEA HERMES P facility. Extension of this program is expected to the equivalent experimental facilities for which sufficient information will be made available. (author)

  3. Modeling hydraulic conductivity and swelling pressure of several kinds of bentonites affected by concentration of saline water

    International Nuclear Information System (INIS)

    Tanaka, Yukihisa; Hasegawa, Takuma; Nakamura, Kunihiko

    2007-01-01

    In case of construction of repository for radioactive waste near the coastal area, the effect of brine on hydraulic conductivity of bentonite as an engineering barrier should be considered because it is known that the hydraulic conductivity of bentonite increases with increasing in salt concentration of water. Thus, the effect of salinity of water on hydraulic conductivity of bentonite has been conducted experimentally. However, it is necessary to elucidate and to model the mechanism of the phenomenon because various kinds of bentonites may possibly be placed in various salinity of salt water. In this study, a model for evaluating permeability of compacted bentonite is proposed considering a) increase in number of sheets of montomorillonite crystal because of cohesion, b) decrease in viscosity of water in interlayer between sheets of montmorillonite crystal. Quantitative evaluation method for permeability of several kinds of bentonite under brine is proposed based on the model mentioned above. (author)

  4. Thermally Actuated Hydraulic Pumps

    Science.gov (United States)

    Jones, Jack; Ross, Ronald; Chao, Yi

    2008-01-01

    Thermally actuated hydraulic pumps have been proposed for diverse applications in which direct electrical or mechanical actuation is undesirable and the relative slowness of thermal actuation can be tolerated. The proposed pumps would not contain any sliding (wearing) parts in their compressors and, hence, could have long operational lifetimes. The basic principle of a pump according to the proposal is to utilize the thermal expansion and contraction of a wax or other phase-change material in contact with a hydraulic fluid in a rigid chamber. Heating the chamber and its contents from below to above the melting temperature of the phase-change material would cause the material to expand significantly, thus causing a substantial increase in hydraulic pressure and/or a substantial displacement of hydraulic fluid out of the chamber. Similarly, cooling the chamber and its contents from above to below the melting temperature of the phase-change material would cause the material to contract significantly, thus causing a substantial decrease in hydraulic pressure and/or a substantial displacement of hydraulic fluid into the chamber. The displacement of the hydraulic fluid could be used to drive a piston. The figure illustrates a simple example of a hydraulic jack driven by a thermally actuated hydraulic pump. The pump chamber would be a cylinder containing encapsulated wax pellets and containing radial fins to facilitate transfer of heat to and from the wax. The plastic encapsulation would serve as an oil/wax barrier and the remaining interior space could be filled with hydraulic oil. A filter would retain the encapsulated wax particles in the pump chamber while allowing the hydraulic oil to flow into and out of the chamber. In one important class of potential applications, thermally actuated hydraulic pumps, exploiting vertical ocean temperature gradients for heating and cooling as needed, would be used to vary hydraulic pressures to control buoyancy in undersea research

  5. Avoidance of transmission line pressure oscillations in discrete hydraulic systems – by shaping of valve opening characteristics

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Pedersen, Henrik C.; Bech, Michael Møller

    2015-01-01

    The architecture of multi pressure line discrete fluid power force systems imposes rapid pressure shifts in the actuator volumes. These fast shifts between pressure levels often introduce pressure oscillations in the actuator chamber and connecting pipes. The topic of this paper is to perform...... pressure shifts by changing the connection between various fixed pressure lines without introducing significant pressure oscillation. As a case study a discrete force system is utilised is a Power Take Off(PTO) system of a wave energy converter. Four pressure shifting algorithms are proposed...

  6. Thermal hydraulic analysis of aggressive secondary cooldown in a small break loss of coolant accident with a total loss of high pressure safety injection

    International Nuclear Information System (INIS)

    Han, Seok Jung; Lim, Ho Gon; Yang, Joon Eon

    2003-01-01

    To support the development of a Probabilistic Safety Assessment (PSA) model usable in Riskinformed Applications (RIA) for Korea Standard Nuclear power Plants (KSNP), we have performed a thermal hydraulic analysis of Aggressive Secondary Cooldown (ASC) in a 2-inch Small Break Loss Of Coolant Accident (SBLOCA) with a total loss of High Pressure Safety Injection (HPSI). The present study focuses on the estimation of the success criteria of ASC, and the enhanced understanding of the detailed thermal hydraulic behavior and phenomena. The results have shown that the Reactor Coolant System (RCS) pressure can be reduced to the Low Pressure Safety Injection (LPSI) operation conditions without core damage. It was also shown that more relaxed success criteria compared to those in the previous PSA models of KSNP could be used in the new PSA model. However, it was found that the results could be affected by various parameters related with ASC operation, i.e., reference temperature for the calculation of the cooldown rate and its control method

  7. Literature survey of heat transfer and hydraulic resistance of water, carbon dioxide, helium and other fluids at supercritical and near-critical pressures

    Energy Technology Data Exchange (ETDEWEB)

    Pioro, I.L.; Duffey, R.B

    2003-04-01

    This survey consists of 430 references, including 269 Russian publications and 161 Western publications devoted to the problems of heat transfer and hydraulic resistance of a fluid at near-critical and supercritical pressures. The objective of the literature survey is to compile and summarize findings in the area of heat transfer and hydraulic resistance at supercritical pressures for various fluids for the last fifty years published in the open Russian and Western literature. The analysis of the publications showed that the majority of the papers were devoted to the heat transfer of fluids at near-critical and supercritical pressures flowing inside a circular tube. Three major working fluids are involved: water, carbon dioxide, and helium. The main objective of these studies was the development and design of supercritical steam generators for power stations (utilizing water as a working fluid) in the 1950s, 1960s, and 1970s. Carbon dioxide was usually used as the modeling fluid due to lower values of the critical parameters. Helium, and sometimes carbon dioxide, were considered as possible working fluids in some special designs of nuclear reactors. (author)

  8. Vibration of hydraulic machinery

    CERN Document Server

    Wu, Yulin; Liu, Shuhong; Dou, Hua-Shu; Qian, Zhongdong

    2013-01-01

    Vibration of Hydraulic Machinery deals with the vibration problem which has significant influence on the safety and reliable operation of hydraulic machinery. It provides new achievements and the latest developments in these areas, even in the basic areas of this subject. The present book covers the fundamentals of mechanical vibration and rotordynamics as well as their main numerical models and analysis methods for the vibration prediction. The mechanical and hydraulic excitations to the vibration are analyzed, and the pressure fluctuations induced by the unsteady turbulent flow is predicted in order to obtain the unsteady loads. This book also discusses the loads, constraint conditions and the elastic and damping characters of the mechanical system, the structure dynamic analysis, the rotor dynamic analysis and the system instability of hydraulic machines, including the illustration of monitoring system for the instability and the vibration in hydraulic units. All the problems are necessary for vibration pr...

  9. Development of a computer code, PZRTR, for the thermal hydraulic analysis of a multi-cavity cold gas pressurizer for an integral reactor, SMART-P

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jae Kwang; Yoon, J

    2003-12-01

    The concept of a Multi-cavity Cold Gas PressuriZeR (MCGPZR) is applied to the SMART: The pressurizer system includes in-vessel cavities and out-of-vessel gas cylinders holding the gas supply/vent system. The gas cylinders are connected to the one of the in-vessel cavities via piping with valves. A pressurizer is maintained at a cold temperature of less than about 100 .deg. C, which is realized with coolers installed in and with wet thermal insulators installed on one of the cavities located inside the hot reactor vessel, to minimize the contribution of a steam partial pressure and is filled with nitrogen gas as a pressure-absorbing medium. The working medium and working temperature of the MCGPZR is totally different from that of a hot steam pressurizer of the commercial PWR. In addition, the MCGPZR is intended to be designed to meet a pressure transient during normal power operation (by its gas volume capacity) without using an active control system and during plant heatup/cooldown operation by using an active gas control (filling/venting) system. Therefore in order to evaluate the feasibility of the concept of the MCGPZR and its intended design goal, the thermal hydraulic behaviors and controllability of the MCGPZR during transients especially a heatup/cooldown operation must be analyzed. In this study, a thermal hydraulic transient analysis computer code, PZRTR, for the Reactor Coolant System (RCS) of an integral reactor composed of the MCGPZR, modular Once-Through Steam Generators (OTSGs), a core and a reactor coolant loop is developed. The pressurizer module (MCGPZR module) of the PZRTR code is based on a two-fluid, nonhomogeneous, nonequilibrium model for the two-phase system behavior and the OTSG module is based on a homogeneous equilibrium model of the two-phase flow process. The core module is simply based on the axial power distributions and the reactor coolant loop is based on the temperature distributions. The code is currently dedicated for the

  10. Standardization of the methodology used for fuel pressure drop evaluation to improve hydraulic calculation of heterogeneous cores

    International Nuclear Information System (INIS)

    Le Borgne, E.; Mattei, A.

    1994-01-01

    Continuous searching for safer and more efficient fuel, and diversification of fuel supply have as a consequence a possible change in the characteristics of the fuel assemblies used in nuclear reactors. By partially refueling cores with new assemblies, nuclear power plant operators are confronted with the problem of heterogeneous cores. The complexity of the problem increases as products diversify in isotopic concentration, types of alloy, size and shape of structure components. This document will focus strictly on the differences in hydraulic resistance related to the modifications in grid structures having no effect on DNB correlations. Although this is an extremely simplified approach to the problem, establishing data to evaluate the hydraulic compatibility between two different assemblies can be difficult, and if not controlled closely, can lead to false conclusions that may affect the operation and safety of the reactor. (authors). 2 figs

  11. Development of a Computer Code, PZRTR rev 1, for the Thermal Hydraulic Analysis of a Multi-Cavity Cold Gas Pressurizer for an Integral Reactor, SMART-P

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jae Kwang; Kang, H. O.; Yoon, J.; Kim, K. K

    2006-12-15

    The concept of a Multi-cavity Cold Gas PressuriZeR(MCGPZR) is applied to the SMART: The pressurizer system includes in-vessel cavities and out-of-vessel gas cylinders holding the gas supply/vent system. The gas cylinders are connected to the one of the in-vessel cavities via piping with valves. A pressurizer is maintained at a cold temperature of less than about 120 .deg. C which is realized with coolers installed in and with wet thermal insulators installed on one of the cavities located inside the hot reactor vessel, to minimize the contribution of a steam partial pressure and is filled with nitrogen gas as a pressure-absorbing medium. The working medium and working temperature of the MCGPZR is totally different from that of a hot steam pressurizer of the commercial PWR. In addition, the MCGPZR is intended to be designed to meet a pressure transient during normal power operation (by its gas volume capacity) without using an active control system and during plant heatup/cooldown operation by using an active gas control (filling/venting) system. Therefore in order to evaluate the feasibility of the concept of the MCGPZR and its intended design goal, the thermal hydraulic behaviors and controllability of the MCGPZR during transients especially a heatup/cooldown operation must be analyzed. In this study, a thermal hydraulic transient analysis computer code, PZRTR rev 1, for the Reactor Coolant System(RCS) of an integral reactor composed of the MCGPZR, modular Once-Through Steam Generators(OTSGs), a core and a reactor coolant loop is developed. The pressurizer module (MCGPZR module) of the PZRTR rev 1 code is based on a two-fluid, nonhomogeneous, nonequilibrium model for the two-phase system behavior and the OTSG module is based on a homogeneous equilibrium model of the two-phase flow process. The core module is simply based on the axial power distributions and the reactor coolant loop is based on the temperature distributions. The code is currently dedicated for the

  12. Thermal hydraulic analysis of aggressive secondary cooldown in small break loss of coolant accident with total loss of high pressure safety injection

    International Nuclear Information System (INIS)

    Han, S. J.; Im, H. K.; Yang, J. U.

    2003-01-01

    Recently, Probabilistic Safety Assessment (PSA) has being applied to various fields as a basic technique of Risk-Informed Applications (RIA). To use RIA, the present study focuses on the detailed thermal hydraulic analyses for major accident sequences and success criteria to support a development of PSA model for Korea Standard Nuclear Power plant (KSNP). The primary purpose of the present study is to evaluate the success criteria of Aggressive Secondary Cooldown (ASC) in Small Break Loss Of Coolant Accident (SBLOCA) with total loss of High Pressure Safety Injection (HPSI) and to enhance the understanding of related thermal hydraulic behavior and phenomena. The accident scenario was 2 inch coldleg break LOCA without HPSI, with 1/2 Low Pressure Safety Injection (LPSI), and performing ASC limited by 55.6 .deg. C /hr (100 .deg. F/hr) cooldown rate at 15 minute after reactor trip, which successively reaches the LPSI condition for about 1.5hr after starting ASC operation with the Peak Cladding Temperature (PCT) of the hottest rod below the core damage criteria 1204.4 .deg. C (2200 .deg. F). In the present study, more relaxed success criteria than the previous PSA for KSNP could be generated under an assumption that operator should maintain the adequate ASC operation. However, it is necessary to evaluate uncertainties arisen from the related parameters of the ASC operation

  13. Hydraulic Hybrid Fleet Vehicle Testing | Transportation Research | NREL

    Science.gov (United States)

    Hydraulic Hybrid Fleet Vehicle Evaluations Hydraulic Hybrid Fleet Vehicle Evaluations How Hydraulic Hybrid Vehicles Work Hydraulic hybrid systems can capture up to 70% of the kinetic energy that would -pressure reservoir to a high-pressure accumulator. When the vehicle accelerates, fluid in the high-pressure

  14. Urban tree species show the same hydraulic response to vapor pressure deficit across varying tree size and environmental conditions.

    Directory of Open Access Journals (Sweden)

    Lixin Chen

    Full Text Available The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations.We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP. The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1 the influence of tree species and size on transpiration, and 2 the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH and tree canopy transpiration amount (E(c was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between G(c at VPD = 1 kPa (G(cref and the G(c sensitivity to VPD (-dG(c/dlnVPD across studied species as well as under contrasting soil water and R(s conditions in the urban area.We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of G(cref.

  15. Urban tree species show the same hydraulic response to vapor pressure deficit across varying tree size and environmental conditions.

    Science.gov (United States)

    Chen, Lixin; Zhang, Zhiqiang; Ewers, Brent E

    2012-01-01

    The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations. We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP). The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1) the influence of tree species and size on transpiration, and 2) the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH) and tree canopy transpiration amount (E(c)) was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between G(c) at VPD = 1 kPa (G(cref)) and the G(c) sensitivity to VPD (-dG(c)/dlnVPD) across studied species as well as under contrasting soil water and R(s) conditions in the urban area. We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of G(cref).

  16. Hydraulic manipulator research at ORNL

    International Nuclear Information System (INIS)

    Kress, R.L.; Jansen, J.F.; Love, L.J.

    1997-01-01

    Recently, task requirements have dictated that manipulator payload capacity increase to accommodate greater payloads, greater manipulator length, and larger environmental interaction forces. General tasks such as waste storage tank cleanup and facility dismantlement and decommissioning require manipulator life capacities in the range of hundreds of pounds rather than tens of pounds. To meet the increased payload capacities demanded by present-day tasks, manipulator designers have turned once again to hydraulics as a means of actuation. In order to successfully design, build, and deploy a new hydraulic manipulator (or subsystem), sophisticated modeling, analysis, and control experiments are usually needed. Oak Ridge National Laboratory (ORNL) has a history of projects that incorporate hydraulics technology, including mobile robots, teleoperated manipulators, and full-scale construction equipment. In addition, to support the development and deployment of new hydraulic manipulators, ORNL has outfitted a significant experimental laboratory and has developed the software capability for research into hydraulic manipulators, hydraulic actuators, hydraulic systems, modeling of hydraulic systems, and hydraulic controls. The purpose of this article is to describe the past hydraulic manipulator developments and current hydraulic manipulator research capabilities at ORNL. Included are example experimental results from ORNL's flexible/prismatic test stand

  17. Hydraulic manipulator research at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Kress, R.L.; Jansen, J.F. [Oak Ridge National Lab., TN (United States); Love, L.J. [Oak Ridge Inst. for Science and Education, TN (United States)

    1997-03-01

    Recently, task requirements have dictated that manipulator payload capacity increase to accommodate greater payloads, greater manipulator length, and larger environmental interaction forces. General tasks such as waste storage tank cleanup and facility dismantlement and decommissioning require manipulator life capacities in the range of hundreds of pounds rather than tens of pounds. To meet the increased payload capacities demanded by present-day tasks, manipulator designers have turned once again to hydraulics as a means of actuation. In order to successfully design, build, and deploy a new hydraulic manipulator (or subsystem), sophisticated modeling, analysis, and control experiments are usually needed. Oak Ridge National Laboratory (ORNL) has a history of projects that incorporate hydraulics technology, including mobile robots, teleoperated manipulators, and full-scale construction equipment. In addition, to support the development and deployment of new hydraulic manipulators, ORNL has outfitted a significant experimental laboratory and has developed the software capability for research into hydraulic manipulators, hydraulic actuators, hydraulic systems, modeling of hydraulic systems, and hydraulic controls. The purpose of this article is to describe the past hydraulic manipulator developments and current hydraulic manipulator research capabilities at ORNL. Included are example experimental results from ORNL`s flexible/prismatic test stand.

  18. Hydraulic lifter of a drilling unit

    Energy Technology Data Exchange (ETDEWEB)

    Velikovskiy, L S; Demin, A V; Shadchinov, L M

    1979-01-08

    The invention refers to drilling equipment, in particular, devices for lowering and lifting operations during drilling. A hydraulic lifter of the drilling unit is suggested which contains a hydraulic cylinder, pressure line and hollow plunger whose cavities are hydraulically connected. In order to improve the reliability of the hydraulic lifter by balancing the forces of compression in the plunger of the hydraulic cylinder, a closed vessel is installed inside the plunger and rigidly connected to its ends. Its cavity is hydraulically connected to the pressure line.

  19. Classification and modelling of functional outputs of computation codes. Application to accidental thermal-hydraulic calculations in pressurized water reactor (PWR)

    International Nuclear Information System (INIS)

    Auder, Benjamin

    2011-01-01

    This research thesis has been made within the frame of a project on nuclear reactor vessel life. It deals with the use of numerical codes aimed at estimating probability densities for every input parameter in order to calculate probability margins at the output level. More precisely, it deals with codes with one-dimensional functional responses. The author studies the numerical simulation of a pressurized thermal shock on a nuclear reactor vessel, i.e. one of the possible accident types. The study of the vessel integrity relies on a thermal-hydraulic analysis and on a mechanical analysis. Algorithms are developed and proposed for each of them. Input-output data are classified using a clustering technique and a graph-based representation. A method for output dimension reduction is proposed, and a regression is applied between inputs and reduced representations. Applications are discussed in the case of modelling and sensitivity analysis for the CATHARE code (a code used at the CEA for the thermal-hydraulic analysis)

  20. Hydraulic structures

    CERN Document Server

    Chen, Sheng-Hong

    2015-01-01

    This book discusses in detail the planning, design, construction and management of hydraulic structures, covering dams, spillways, tunnels, cut slopes, sluices, water intake and measuring works, ship locks and lifts, as well as fish ways. Particular attention is paid to considerations concerning the environment, hydrology, geology and materials etc. in the planning and design of hydraulic projects. It also considers the type selection, profile configuration, stress/stability calibration and engineering countermeasures, flood releasing arrangements and scouring protection, operation and maintenance etc. for a variety of specific hydraulic structures. The book is primarily intended for engineers, undergraduate and graduate students in the field of civil and hydraulic engineering who are faced with the challenges of extending our understanding of hydraulic structures ranging from traditional to groundbreaking, as well as designing, constructing and managing safe, durable hydraulic structures that are economical ...

  1. Combined hydraulic and regenerative braking system

    Science.gov (United States)

    Venkataperumal, R.R.; Mericle, G.E.

    1979-08-09

    A combined hydraulic and regenerative braking system and method for an electric vehicle is disclosed. The braking system is responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially regenerative at a linearly increasing braking force from the first level of applied brake line pressure to a higher second level of brake line pressure, to be partially hydraulic at a linearly increasing braking force and partially regenerative at a linearly decreasing braking force from the second level of applied line pressure to a third and higher level of applied line pressure, and to be completely hydraulic at a linearly increasing braking force from the third level to all higher applied levels of line pressure.

  2. Thermo-hydraulic instability of natural circulation BWRs at low pressure star-up. Experimental estimation of instability region with test facility considering scaling law

    International Nuclear Information System (INIS)

    Inada, F.; Furuya, M.; Yasuo, A.; Tabata, H.; Yoshioka, Y.; Kim, H.T.

    1995-01-01

    In natural circulation BWRs developed for advanced light water reactors with simplified passive safety systems, thermo-hydraulic stability should be confirmed especially at low pressure start-up. In this paper, nondimensional parameters to estimate the hydrodynamic stability to reactors at low pressure start-up were obtained by transformation of the basic equations of drift-flux model in the two-phase region into nondimensional form. A test facility based on these parameters was then constructed. The height of the test facility is 70% of SBWR and many nondimensional test facility parameters are almost the same as those of the reactor. Reactor stability was estimated experimentally. Stability maps below 0.5MPa were obtained on the heat flux - channel inlet subcooling place. It was found that there were two stability boundaries, between which the flow became unstable. Flow was stable in the high and low channel inlet subcooling regions. Typical conditions of SBWR at low pressure start-up were noted in the high channel inlet subcooling stable region. The heat flux at typical SBWR start-up was about one fifth that of the stability boundary. Though some nondimensional parameters of the test facility did not exactly agree with those of SBWR, it was suggested that the flow in SBWR was stable below 0.5MPa because of the large margin. (author)

  3. Thermal-hydraulic oscillations in a low pressure two-phase natural circulation loop at low powers and high inlet subcoolings

    International Nuclear Information System (INIS)

    Wang, S.B.; Wu, J.Y.; Chin Pan; Lin, W.K.

    2004-01-01

    The stability of a natural circulation boiling loop is of great importance and interests for both academic researches and many industrial applications, such as next generation boiling water reactors. The present study investigated the thermal-hydraulic oscillation behavior in a low pressure two-phase natural circulation loop at low powers and high inlet subcoolings. The experiments were conducted at atmospheric pressure with heating power ranging from 4 to 8 kW and inlet subcooling ranging from 27 to 75 deg. C. Significant oscillations in loop mass flow rate, pressure drop in each section, and heated wall and fluid temperatures are present for all the cases studied here. The oscillation is typically quasi-periodic and with flow reversal with magnitudes smaller than forward flows. The magnitude of wall temperature oscillation could be as high as 60 deg. C, which will be of serious concern for practical applications. It is found that the first fundamental oscillation (large magnitude oscillation) frequency increases with increase in heated power and with decrease in inlet subcooling. (author)

  4. Thermal-Hydraulic Integral Effect Test with ATLAS for an Intermediate Break Loss of Coolant Accident at a Pressurizer Surge Line

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyoung Ho; Seok Cho; Park, Hyun Sik; Choi, Nam Hyun; Park, Yu Sun; Kim, Jong Rok; Bae, Byoung Uhn; Kim, Yeon Sik; Kim, Kyung Doo; Choi, Ki Yong; Song, Chul Hwa [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    The main objectives of this test were not only to provide physical insight into the system response of the APR1400 during the pressurizer surge line break accident but also to produce an integral effect test data to validate the SPACE code. In order to simulate a double-ended guillotine break of a pressurizer surge line in the APR1400, the IB-SUR-01R test was performed with ATLAS. The major thermal-hydraulic phenomena such as the system pressures, the collapsed water levels, and the break flow rate were presented and discussed. Despite the core was uncovered, no excursion in the cladding temperature was observed. The pressurizer surge line break can be classified as a hot leg break from a break location point of view. Compared with a cold leg break, coolability in the core may be better in case of a hot leg break due to the enhanced flow in the core region. This integral effect test data will be used to evaluate the prediction capability of existing safety analysis codes of the MARS and the RELAP5 as well as the SPACE code. Furthermore, this data can be utilized to identify any code deficiency for an IBLOCA simulation, especially for DVI-adapted plants. Redefinition of break size for design basis accident (DBA) based on risk information is being extensively investigated due to the potential for safety benefits and unnecessary burden reduction from current LBLOCA (large break loss of coolant accident)-based ECC (Emergency Core Cooling) Acceptance Criteria. As a transition break size (TBS), the rupture of medium-size pipe is considered to be more important than ever in risk-informed regulation (RIR)-relevant safety analysis. As plants age, are up-rated, and continue to seek improved operating efficiencies, the small break and intermediate break LOCA (IBLOCA) can become a concern. In particular, IBLOCA with DVI (Direct Vessel Injection) features will be addressed to support redefinition of a design-basis LOCA. With an aim of expanding code validation to address small

  5. Thermal hydraulic analysis of aggressive secondary cooldown in a small break loss of coolant accident with a total loss of high pressure safety injection

    International Nuclear Information System (INIS)

    Han, Seok Jung; Lim, Ho Gon; Yang, Joon Eon

    2003-03-01

    Recently, Probabilistic Safety Assessment (PSA) has being applied to various fields as a basic technique of Risk-Informed Applications (RIA). The present study focuses on detailed thermal hydraulic analyses for major accident sequences and success criteria to support a development of PSA model using RIA for Korea Standard Nuclear Power plant (KSNP). The primary purpose of the present study in this year is to evaluate the success cri-teria of Aggressive Secondary Cooldown (ASC) in a Small Size Loss Of Coolant Accident (SBLOCA) without HPSI and to enhance the understanding of related thermal hydraulic behavior and phenomena. An effort was made to evaluate the system success criteria and a mission time for the recovery action by an operator to prevent the core damage for that accident scenario. The accident scenario for KSNP was a 2 inch coldleg break LOCA with a total loss of High Pressure Safety Injection (HPSI) and 1/2 Low Pressure Safety Injection (LPSI) available and perform-ing ASC limited by 55.6 .deg. C/hr (100 .deg. F/hr) cooldown rate at 15 minute after reactor trip. It successively reached the LPSI condition for about 1.5hr after starting the ASC operation with the Peak Cladding Temperature (PCT) of the hottest rod below the core damage criteria of 1204.4 .deg. C (2200 .deg. F). Sensitivity studies were performed for (1) cool-ant average temperature parameters, (2) ASC operation control method, (3) operation start time, (4) 1 inch break size. The present analysis identified thermal hydraulic phenomena and parameters affecting on the behavior, which consist of coolant break flow and inventory, parameters governing secondary heat removal, ASC operation control method, and its reference temperature parameters. In the present study, more relaxed success criteria than the previous PSA for KSNP could be generated under an assumption that an operator should maintain the ade-quate ASC operation. However, it is necessary to evaluate the uncertainties arisen from the

  6. Semi-analytical prediction of hydraulic resistance and heat transfer for pipe and channel flows of water at supercritical pressure

    International Nuclear Information System (INIS)

    Laurien, E.

    2012-01-01

    Within the Generation IV International Forum the Supercritical Water Reactor is investigated. For its core design and safety analysis the efficient prediction of flow and heat transfer parameters such as the wall-shear stress and the heat-transfer coefficient for pipe and channel flows is needed. For circular pipe flows a numerical model based on the one-dimensional conservation equations of mass, momentum end energy in the radial direction is presented, referred to as a 'semi-analytical' method. An accurate, high-order numerical method is employed to evaluate previously derived analytical solutions of the governing equations. Flow turbulence is modeled using the algebraic approach of Prandtl/van-Karman, including a model for the buffer layer. The influence of wall roughness is taken into account by a new modified numerical damping function of the turbulence model. The thermo-hydraulic properties of water are implemented according to the international standard of 1997. This method has the potential to be used within a sub-channel analysis code and as wall-functions for CFD codes to predict the wall shear stress and the wall temperature. The present study presents a validation of the method with comparison of model results with experiments and multi-dimensional computational (CFD) studies in a wide range of flow parameters. The focus is laid on forced convection flows related to reactor design and near-design conditions. It is found, that the method can accurately predict the wall temperature even under deterioration conditions as they occur in the selected experiments (Yamagata el al. 1972 at 24.5 MPa, Ornatski et al. 1971 at 25.5 and Swenson et al. 1963 at 22.75 MPa). Comparison of the friction coefficient under high heat flux conditions including significant viscosity and density reductions near the wall with various correlations for the hydraulic resistance will be presented; the best agreement is achieve with the correlation of Pioro et al. 2004. It is

  7. Cavitation in Hydraulic Machinery

    Energy Technology Data Exchange (ETDEWEB)

    Kjeldsen, M.

    1996-11-01

    The main purpose of this doctoral thesis on cavitation in hydraulic machinery is to change focus towards the coupling of non-stationary flow phenomena and cavitation. It is argued that, in addition to turbulence, superimposed sound pressure fluctuations can have a major impact on cavitation and lead to particularly severe erosion. For the design of hydraulic devices this finding may indicate how to further limit the cavitation problems. Chapter 1 reviews cavitation in general in the context of hydraulic machinery, emphasizing the initial cavitation event and the role of the water quality. Chapter 2 discusses the existence of pressure fluctuations for situations common in such machinery. Chapter 3 on cavitation dynamics presents an algorithm for calculating the nucleation of a cavity cluster. Chapter 4 describes the equipment used in this work. 53 refs., 55 figs.,10 tabs.

  8. Control rod drive hydraulic device

    International Nuclear Information System (INIS)

    Takekawa, Toru.

    1994-01-01

    The device of the present invention can reliably prevent a possible erroneous withdrawal of control rod driving mechanism when the pressure of a coolant line is increased by isolation operation of hydraulic control units upon periodical inspection for a BWR type reactor. That is, a coolant line is connected to the downstream of a hydraulic supply device. The coolant line is connected to a hydraulic control unit. A coolant hydraulic detection device and a pressure setting device are disposed to the coolant line. A closing signal line and a returning signal line are disposed, which connect the hydraulic supply device and a flow rate control valve for the hydraulic setting device. In the device of the present invention, even if pressure of supplied coolants is elevated due to isolation of hydraulic control units, the elevation of the hydraulic pressure can be prevented. Accordingly, reliability upon periodical reactor inspection can be improved. Further, the facility is simplified and the installation to an existent facility is easy. (I.S.)

  9. A study on the pressure ripple characteristics in a bent-axis type oil hydraulic piston pump

    International Nuclear Information System (INIS)

    Cho, Ihn Sung; Jung, Jae Youn

    2013-01-01

    To improve the performance of a bent-axis type axial piston pump driven by tapered pistons, it is necessary to know the pressure ripple characteristics. The purpose of this paper is to understand the effect on the pressure ripple characteristics, and to predict by comparing experimental and theoretical analysis results. The simulation model of a bent-axis type axial piston pump is developed in the AMESim environment using the geometrical dimension, and the driving mechanism of the piston pump, such as the stroke of pump, the velocity of piston, the instantaneous volumetric flow, the overlap area of valve plate opening to cylinder bore, the angle of notch, and so on. The results show that theoretical analysis results of the bent-axis type axial piston pump by using the AMESim approximate the pressure ripple characteristic of the test pump, and through this, simulations can be obtained that predict the performance characteristics of a bentaxis type axial piston pump.

  10. Hydraulic turbines

    International Nuclear Information System (INIS)

    Meluk O, G.

    1998-01-01

    The hydraulic turbines are defined according to the specific speed, in impulse turbines and in reaction turbines. Currently, the Pelton turbines (of impulse) and the Francis and Kaplan turbines (of reaction), they are the most important machines in the hydroelectric generation. The hydraulic turbines are capable of generating in short times, large powers, from its loads zero until the total load and reject the load instantly without producing damages in the operation. When the hydraulic resources are important, the hydraulic turbines are converted in the axle of the electric system. Its combination with thermoelectric generation systems, it allow the continuing supply of the variations in demand of energy system. The available hydraulic resource in Colombia is of 93085 MW, of which solely 9% is exploited, become 79% of all the electrical country generation, 21% remaining is provided by means of the thermoelectric generation

  11. Experimental study on thermal-hydraulic behaviors of a pressure balanced coolant injection system for a passive safety light water reactor JPSR

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Takashi; Watanabe, Hironori; Araya, Fumimasa; Nakajima, Katsutoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Iwamura, Takamichi; Murao, Yoshio

    1998-02-01

    A conceptual design study of a passive safety light water reactor JPSR has been performed at Japan Atomic Energy Research Institute JAERI. A pressure balanced coolant injection experiment has been carried out, with an objective to understand thermal-hydraulic characteristics of a passive coolant injection system which has been considered to be adopted to JPSR. This report summarizes experimental results and data recorded in experiment run performed in FY. 1993 and 1994. Preliminary experiments previously performed are also briefly described. As the results of the experiment, it was found that an initiation of coolant injection was delayed with increase in a subcooling in the pressure balance line. By inserting a separation device which divides the inside of core make-up tank (CMT) into several small compartments, a diffusion of a high temperature region formed just under the water surface was restrained and then a steam condensation was suppressed. A time interval from an uncovery of the pressure balance line to the initiation of the coolant injection was not related by a linear function with a discharge flow rate simulating a loss-of-coolant accident (LOCA) condition. The coolant was injected intermittently by actuation of a trial fabricated passive valve actuated by pressure difference for the present experiment. It was also found that the trial passive valve had difficulties in setting an actuation set point and vibrations noises and some fraction of the coolant was remained in CMT without effective use. A modification was proposed for resolving these problems by introducing an anti-closing mechanism. (author)

  12. TRAC-PF1/MOD1: an advanced best-estimate computer program for pressurized water reactor thermal-hydraulic analysis

    International Nuclear Information System (INIS)

    Liles, D.R.; Mahaffy, J.H.

    1986-07-01

    The Los Alamos National Laboratory is developing the Transient Reactor Analysis Code (TRAC) to provide advanced best-estimate predictions of postulated accidents in light-water reactors. The TRAC-PF1/MOD1 program provides this capability for pressurized water reactors and for many thermal-hydraulic test facilities. The code features either a one- or a three-dimensional treatment of the pressure vessel and its associated internals, a two-fluid nonequilibrium hydrodynamics model with a noncondensable gas field and solute tracking, flow-regime-dependent constitutive equation treatment, optional reflood tracking capability for bottom-flood and falling-film quench fronts, and consistent treatment of entire accident sequences including the generation of consistent initial conditions. The stability-enhancing two-step (SETS) numerical algorithm is used in the one-dimensional hydrodynamics and permits this portion of the fluid dynamics to violate the material Courant condition. This technique permits large time steps and, hence, reduced running time for slow transients

  13. TRAC-PF1/MOD1: an advanced best-estimate computer program for pressurized water reactor thermal-hydraulic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Liles, D.R.; Mahaffy, J.H.

    1986-07-01

    The Los Alamos National Laboratory is developing the Transient Reactor Analysis Code (TRAC) to provide advanced best-estimate predictions of postulated accidents in light-water reactors. The TRAC-PF1/MOD1 program provides this capability for pressurized water reactors and for many thermal-hydraulic test facilities. The code features either a one- or a three-dimensional treatment of the pressure vessel and its associated internals, a two-fluid nonequilibrium hydrodynamics model with a noncondensable gas field and solute tracking, flow-regime-dependent constitutive equation treatment, optional reflood tracking capability for bottom-flood and falling-film quench fronts, and consistent treatment of entire accident sequences including the generation of consistent initial conditions. The stability-enhancing two-step (SETS) numerical algorithm is used in the one-dimensional hydrodynamics and permits this portion of the fluid dynamics to violate the material Courant condition. This technique permits large time steps and, hence, reduced running time for slow transients.

  14. The Process of Hydraulic Fracturing

    Science.gov (United States)

    Hydraulic fracturing, know as fracking or hydrofracking, produces fractures in a rock formation by pumping fluids (water, proppant, and chemical additives) at high pressure down a wellbore. These fractures stimulate the flow of natural gas or oil.

  15. Basic hydraulics

    CERN Document Server

    Smith, P D

    1982-01-01

    BASIC Hydraulics aims to help students both to become proficient in the BASIC programming language by actually using the language in an important field of engineering and to use computing as a means of mastering the subject of hydraulics. The book begins with a summary of the technique of computing in BASIC together with comments and listing of the main commands and statements. Subsequent chapters introduce the fundamental concepts and appropriate governing equations. Topics covered include principles of fluid mechanics; flow in pipes, pipe networks and open channels; hydraulic machinery;

  16. An experimental study on single phase convection heat transfer and pressure drop in two brazed plate heat exchangers with different chevron shapes and hydraulic diameters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Man Bae; Park, Chang Yong [Seoul National University of Science and Technology, Seoul (Korea, Republic of)

    2017-05-15

    An experimental study on heat transfer and pressure drop characteristics was performed at single phase flow in two Brazed plate heat exchangers (BPHEs) with different geometries. The corrugation density of one of the BPHE (Type II) was two times as high as that of the other BPHE (Type I). The hydraulic diameter of the type II BPHE was 2.13 mm, which was 38 % smaller than that of the type I BPHE. Also, the cross section shape of the flow channels for the type II BPHE was different from that for conventional BPHEs due to the unusual corrugation patterns and brazing points. The experimental conditions for temperatures were varied from 4.6 °C to 49.1 °C, and for mass flow rates were changed from 0.07 kg/s to 1.24 kg/s. The measured results showed that pressure drop in the type II BPHE was about 110 % higher than that in the type I BPHE. Nu of the type II was higher than that of the type I BPHE and the enhancement became larger with the increase of Re at the ranges above 800. New correlations for fF and Nu were proposed by this study and their prediction accuracy could be improved by considering the surface enlargement factor in the correlations. The performance evaluation of the two BPHEs was performed by (j/f{sub F}1{sup /3}) which represented the ratio of heat transfer and pressure drop performance. Also, a new parameter, the capacity compactness of PHE, was proposed and it presented the PHE capacity per unit volume and unit log mean temperature difference. The comparison showed that the two BPHEs had similar values of the (j/f{sub F}1{sup /3}), whereas they had significantly different values of the capacity compactness. The capacity compactness of the type II BPHE was 1.5 times higher than that for the type I BPHE.

  17. An experimental study on single phase convection heat transfer and pressure drop in two brazed plate heat exchangers with different chevron shapes and hydraulic diameters

    International Nuclear Information System (INIS)

    Kim, Man Bae; Park, Chang Yong

    2017-01-01

    An experimental study on heat transfer and pressure drop characteristics was performed at single phase flow in two Brazed plate heat exchangers (BPHEs) with different geometries. The corrugation density of one of the BPHE (Type II) was two times as high as that of the other BPHE (Type I). The hydraulic diameter of the type II BPHE was 2.13 mm, which was 38 % smaller than that of the type I BPHE. Also, the cross section shape of the flow channels for the type II BPHE was different from that for conventional BPHEs due to the unusual corrugation patterns and brazing points. The experimental conditions for temperatures were varied from 4.6 °C to 49.1 °C, and for mass flow rates were changed from 0.07 kg/s to 1.24 kg/s. The measured results showed that pressure drop in the type II BPHE was about 110 % higher than that in the type I BPHE. Nu of the type II was higher than that of the type I BPHE and the enhancement became larger with the increase of Re at the ranges above 800. New correlations for fF and Nu were proposed by this study and their prediction accuracy could be improved by considering the surface enlargement factor in the correlations. The performance evaluation of the two BPHEs was performed by (j/f F 1 /3 ) which represented the ratio of heat transfer and pressure drop performance. Also, a new parameter, the capacity compactness of PHE, was proposed and it presented the PHE capacity per unit volume and unit log mean temperature difference. The comparison showed that the two BPHEs had similar values of the (j/f F 1 /3 ), whereas they had significantly different values of the capacity compactness. The capacity compactness of the type II BPHE was 1.5 times higher than that for the type I BPHE.

  18. Hydraulic Structures

    Data.gov (United States)

    Department of Homeland Security — This table is required whenever hydraulic structures are shown in the flood profile. It is also required if levees are shown on the FIRM, channels containing the...

  19. Thermal-hydraulics of wave propagation and pressure distribution under hypothetical steam explosion conditions in the ANS reactor

    Energy Technology Data Exchange (ETDEWEB)

    Taleyarkhan, R.P.; Georgevich, V.; N-Valenit, S.; Kim, S.H. [Oak Ridge National Lab., TN (United States)

    1995-09-01

    This paper describes salient aspects of the modeling and analysis framework for evaluation of dynamic loads, wave propagation, and pressure distributions (under hypothetical steam explosion conditions) around key structural boundaries of the Advanced Neutron Source (ANS) reactor core region. A staged approach was followed, using simple thermodynamic models for bounding loads and the CTH code for evaluating realistic estimates in a staged multidimensional framework. Effects of nodalization, melt dispersal into coolant during explosion, single versus multidirectional dissipation, energy level of melt, and rate of energy deposition into coolant were studied. The importance of capturing multidimensional effects that simultaneously account for fluid-structural interactions was demonstrated. As opposed to using bounding loads from thermodynamic evaluations, it was revealed that the ANS reactor system will not be vulnerable to vertically generated missiles that threaten containment if realistic estimates of energetics are used (from CTH calculations for thermally generated steam explosions without significant aluminum ignition).

  20. Hydraulic nuts (hydranuts) for critical bolted joints

    International Nuclear Information System (INIS)

    Greenwell, S.

    2008-01-01

    HydraNuts replace the original nut and torquing equipment, combining the two functions into one system. Designed for simple installation and operation, HydraNuts are fitted to the stud bolts. Once all HydraNuts are fitted to the application, flexible hydraulic hoses are connected, forming a closed loop hydraulic harness, allowing simultaneous pressurization of all HydraNuts. Hydraulic pressure is obtained by the use of a pumping unit and the resultant load generated is transferred to the studs and flange closure is obtained. Locking rings are rotated into place, supporting the tensioned load mechanically after hydraulic pressure is released. The hose harness is removed. (author)

  1. Hybrid equation/agent-based model of ischemia-induced hyperemia and pressure ulcer formation predicts greater propensity to ulcerate in subjects with spinal cord injury.

    Directory of Open Access Journals (Sweden)

    Alexey Solovyev

    Full Text Available Pressure ulcers are costly and life-threatening complications for people with spinal cord injury (SCI. People with SCI also exhibit differential blood flow properties in non-ulcerated skin. We hypothesized that a computer simulation of the pressure ulcer formation process, informed by data regarding skin blood flow and reactive hyperemia in response to pressure, could provide insights into the pathogenesis and effective treatment of post-SCI pressure ulcers. Agent-Based Models (ABM are useful in settings such as pressure ulcers, in which spatial realism is important. Ordinary Differential Equation-based (ODE models are useful when modeling physiological phenomena such as reactive hyperemia. Accordingly, we constructed a hybrid model that combines ODEs related to blood flow along with an ABM of skin injury, inflammation, and ulcer formation. The relationship between pressure and the course of ulcer formation, as well as several other important characteristic patterns of pressure ulcer formation, was demonstrated in this model. The ODE portion of this model was calibrated to data related to blood flow following experimental pressure responses in non-injured human subjects or to data from people with SCI. This model predicted a higher propensity to form ulcers in response to pressure in people with SCI vs. non-injured control subjects, and thus may serve as novel diagnostic platform for post-SCI ulcer formation.

  2. An analysis of the factors affecting the hydraulic conductivity and swelling pressure of Kyungju ca-bentonite for use as a clay-based sealing material for a high level waste repository

    International Nuclear Information System (INIS)

    Cho, Won Jin; Lee, Jae Owen; Kwon, Sang Ki

    2012-01-01

    The buffer and backfill are important components of the engineered barrier system in a high-level waste repository, which should be constructed in a hard rock formation at a depth of several hundred meters below the ground surface. The primary function of the buffer and backfill is to seal the underground excavation as a preferred flow path for radionuclide migration from the deposited high-level waste. This study investigates the hydraulic conductivity and swelling pressure of Kyungju Ca-bentonite, which is the candidate material for the buffer and backfill in the Korean reference high-level waste disposal system. The factors that influence the hydraulic conductivity and swelling pressure of the buffer and backfill are analyzed. The factors considered are the dry density, the temperature, the sand content, the salinity and the organic carbon content. The possibility of deterioration in the sealing performance of the buffer and backfill is also assessed.

  3. Modeling and stability of electro-hydraulic servo of hydraulic excavator

    Science.gov (United States)

    Jia, Wenhua; Yin, Chenbo; Li, Guo; Sun, Menghui

    2017-11-01

    The condition of the hydraulic excavator is complicated and the working environment is bad. The safety and stability of the control system is influenced by the external factors. This paper selects hydraulic excavator electro-hydraulic servo system as the research object. A mathematical model and simulation model using AMESIM of servo system is established. Then the pressure and flow characteristics are analyzed. The design and optimization of electro-hydraulic servo system and its application in engineering machinery is provided.

  4. Decoupling the influence of leaf and root hydraulic conductances on stomatal conductance and its sensitivity to vapour pressure deficit as soil dries in a drained loblolly pine plantation

    Science.gov (United States)

    J.-C. Domec; A. Noormets; Ge Sun; J. King; Steven McNulty; Michael Gavazzi; Johnny Boggs; Emrys Treasure

    2009-01-01

    The study examined the relationships between whole tree hydraulic conductance (Ktree) and the conductance in roots (Kroot) and leaves (Kleaf) in loblolly pine trees. In addition, the role of seasonal variations in Kroot and Kleaf in mediating stomatal...

  5. Mechanics of Hydraulic Fractures

    Science.gov (United States)

    Detournay, Emmanuel

    2016-01-01

    Hydraulic fractures represent a particular class of tensile fractures that propagate in solid media under pre-existing compressive stresses as a result of internal pressurization by an injected viscous fluid. The main application of engineered hydraulic fractures is the stimulation of oil and gas wells to increase production. Several physical processes affect the propagation of these fractures, including the flow of viscous fluid, creation of solid surfaces, and leak-off of fracturing fluid. The interplay and the competition between these processes lead to multiple length scales and timescales in the system, which reveal the shifting influence of the far-field stress, viscous dissipation, fracture energy, and leak-off as the fracture propagates.

  6. “三软”煤层水力冲孔卸压增透技术研究%Study on pressure releasing and permeability improving technology with hydraulic flushing in “three soft”coal seam

    Institute of Scientific and Technical Information of China (English)

    何志龙; 孙谦; 宋大钊; 高勤琼

    2015-01-01

    针对糯东煤矿“三软”高瓦斯低透气性煤层易流变、难抽采的问题,提出了底板巷道穿层水力冲孔卸压增透技术,并在糯东煤矿11702掘进工作面进行了现场试验。结果表明:冲孔后比冲孔前抽采瓦斯浓度上升3.4倍,瓦斯抽采流量增加4.4倍,炮掘工作面回风流中的瓦斯(体积分数)由冲孔前0.8%的超限预警状态变成冲孔后的0.4%的安全范围,水力冲孔技术应用效果显著,在糯东煤矿取得了良好的卸压增透效果。%To solve the problem of easy rheology and hard drainage in"three soft"coal seam with high gas concentration and low permeability in Nuodong coal mine,the pressure releasing and permeability improving technology with hydraulic flushing in floor gateway was proposed,and corresponding field test at the No.11702 heading face of Nuodong coal mine was carried out.The re-sults show that the drained gas concentration after hydraulic flushing is 3.4 times as that without hydraulic flushing and the gas flow rate is increased by 4.4 times;and the gas concentration at the blasting working face changes from 0.8% (overrun warning state,before hydraulic flushing)to 0.4% (safety state,after hydraulic flushing).The application of hydraulic flushing technolo-gy is more effective and remarkable in releasing pressure and improving permeability in Nuodong coal mine.

  7. Numerical simulation of water hammer in low pressurized pipe: comparison of SimHydraulics and Lax-Wendroff method with experiment

    Science.gov (United States)

    Himr, D.

    2013-04-01

    Article describes simulation of unsteady flow during water hammer with two programs, which use different numerical approaches to solve ordinary one dimensional differential equations describing the dynamics of hydraulic elements and pipes. First one is Matlab-Simulink-SimHydraulics, which is a commercial software developed to solve the dynamics of general hydraulic systems. It defines them with block elements. The other software is called HYDRA and it is based on the Lax-Wendrff numerical method, which serves as a tool to solve the momentum and continuity equations. This program was developed in Matlab by Brno University of Technology. Experimental measurements were performed on a simple test rig, which consists of an elastic pipe with strong damping connecting two reservoirs. Water hammer is induced with fast closing the valve. Physical properties of liquid and pipe elasticity parameters were considered in both simulations, which are in very good agreement and differences in comparison with experimental data are minimal.

  8. Numerical simulation of water hammer in low pressurized pipe: comparison of SimHydraulics and Lax-Wendroff method with experiment

    Directory of Open Access Journals (Sweden)

    Himr D.

    2013-04-01

    Full Text Available Article describes simulation of unsteady flow during water hammer with two programs, which use different numerical approaches to solve ordinary one dimensional differential equations describing the dynamics of hydraulic elements and pipes. First one is Matlab-Simulink-SimHydraulics, which is a commercial software developed to solve the dynamics of general hydraulic systems. It defines them with block elements. The other software is called HYDRA and it is based on the Lax-Wendrff numerical method, which serves as a tool to solve the momentum and continuity equations. This program was developed in Matlab by Brno University of Technology. Experimental measurements were performed on a simple test rig, which consists of an elastic pipe with strong damping connecting two reservoirs. Water hammer is induced with fast closing the valve. Physical properties of liquid and pipe elasticity parameters were considered in both simulations, which are in very good agreement and differences in comparison with experimental data are minimal.

  9. A Computational Model of Hydraulic Volume Displacement Drive

    Directory of Open Access Journals (Sweden)

    V. N. Pil'gunov

    2014-01-01

    Full Text Available The paper offers a computational model of industrial-purpose hydraulic drive with two hydraulic volume adjustable working chamber machines (pump and motor. Adjustable pump equipped with the pressure control unit can be run together with several adjustable hydraulic motors on the principle of three-phase hydraulic socket-outlet with high-pressure lines, drain, and drainage system. The paper considers the pressure-controlled hydrostatic transmission with hydraulic motor as an output link. It shows a possibility to create a saving hydraulic drive using a functional tie between the adjusting parameters of the pump and hydraulic motor through the pressure difference, torque, and angular rate of the hydraulic motor shaft rotation. The programmable logic controller can implement such tie. The Coulomb and viscous frictions are taken into consideration when developing a computational model of the hydraulic volume displacement drive. Discharge balance considers external and internal leakages in equivalent clearances of hydraulic machines, as well as compression loss volume caused by hydraulic fluid compressibility and deformation of pipe walls. To correct dynamic properties of hydraulic drive, the paper offers that in discharge balance are included the additional regulated external leakages in the open circuit of hydraulic drive and regulated internal leakages in the closed-loop circuit. Generalized differential equations having functional multipliers and multilinked nature have been obtained to describe the operation of hydraulic positioning and speed drive with two hydraulic volume adjustable working chamber machines. It is shown that a proposed computational model of hydraulic drive can be taken into consideration in development of LS («Load-Sensing» drives, in which the pumping pressure is tuned to the value required for the most loaded slave motor to overcome the load. Results attained can be used both in designing the industrial-purpose heavy

  10. A HISTORICAL PERSPECTIVE OF NUCLEAR THERMAL HYDRAULICS

    Energy Technology Data Exchange (ETDEWEB)

    D’Auria, F; Rohatgi, Upendra S.

    2017-01-12

    The nuclear thermal-hydraulics discipline was developed following the needs for nuclear power plants (NPPs) and, to a more limited extent, research reactors (RR) design and safety. As in all other fields where analytical methods are involved, nuclear thermal-hydraulics took benefit of the development of computers. Thermodynamics, rather than fluid dynamics, is at the basis of the development of nuclear thermal-hydraulics together with the experiments in complex two-phase situations, namely, geometry, high thermal density, and pressure.

  11. Free surface flow under gravity and surface tension due to an applied pressure distribution: i Bond number greater than one-third

    Energy Technology Data Exchange (ETDEWEB)

    Maleewong, Montri; Asavanant, Jack [Chulalongkorn University, Department of Mathematics and Advanced Virtual Intelligence Computing Center, Bangkok (Thailand); Grimshaw, Roger [Loughborough University, Department of Mathematical Sciences, Loughborough (United Kingdom)

    2005-08-01

    We consider steady free surface two-dimensional flow due to a localized applied pressure distribution under the effects of both gravity and surface tension in water of constant depth, and in the presence of a uniform stream. The fluid is assumed to be inviscid and incompressible, and the flow is irrotational. The behavior of the forced nonlinear waves is characterized by three parameters: the Froude number, F, the Bond number, {tau}>1/3, and the magnitude and sign of the pressure forcing parameter {epsilon}. The fully nonlinear wave problem is solved numerically by using a boundary integral method. For small amplitude waves and F<1 but not too close to 1, linear theory gives a good prediction for the numerical solution of the nonlinear problem in the case of bifurcation from the uniform flow. As F approaches 1, the nonlinear terms need to be taken account of. In this case the forced Korteweg-de Vries equation is found to be an appropriate model to describe bifurcations from an unforced solitary wave. In general, it is found that for given values of F<1 and {tau}>1/3, there exists both elevation and depression waves. In some cases, a limiting configuration in the form of a trapped bubble occurs in the depression wave solutions. (orig.)

  12. Thermal hydraulic evaluation for an experimental facility to investigate pressurized thermal shock (PTS) in CDTN/CNEN; Avaliacao termo-hidraulica da montagem experimental de choque termico pressurizado do CDTN/CNEN

    Energy Technology Data Exchange (ETDEWEB)

    Palmieri, Elcio T.; Navarro, Moyses A.; Aronne, Ivam D.; Terra, Jose L. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)

    2002-07-01

    The goal of the work presented in this paper is to provide necessary thermal hydraulics information to the design of an experimental installation to investigate the Pressurized Thermal Shock (PTS) to be implemented at Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN). The envisaged installation has a test section that represents, in a small scale, a pressure vessel of a nuclear reactor. This test section will be heated and then exposed to a PTS in order to evaluate the appearance and development of cracks. To verify the behavior of the temperatures of the pressure vessel after a sudden flood through the annulus, calculations were made using the RELAP5/MOD 3.2.2 gamma code. Different outer radiuses were studied for the annular region. The results showed that the smaller annulus spacing (20 mm) anticipates the wetting of the surface and produces a higher cooling of the external surface, which stays completely wet for a longer time. (author)

  13. Spatio-temporal evolution of apparent resistivity during coal-seam hydraulic flushing

    Science.gov (United States)

    Li, Dexing; Wang, Enyuan; Song, Dazhao; Qiu, Liming; Kong, Xiangguo

    2018-06-01

    Hydraulic flushing in gas predrainage is widely used, but the hydraulic-flushing effect is evaluated in a traditional way, by determining the desorption volume, moisture content, gas drainage rate and other conventional indices. To verify the rationality and feasibility of the multielectrode resistivity method in the evaluation of coal-seam hydraulic flushing and to research the spatio-temporal evolution of apparent resistivity during hydraulic flushing, a field test was conducted in 17# coal seam at Nuodong Mine, Guizhou. During hydraulic flushing, four stages were defined according to the variation in coal rock resistivity with time, namely, the preparation stage, the sharply decreasing stage, the rapidly increasing stage and the steady stage. The apparent resistivity of the coal rock mass is affected mainly by its own degree of fragmentation and flushing volume. A more serious rupture and a greater flushing volume yield a smaller apparent resistivity during the sharply decreasing stage and a higher resistivity during the stable stage. After three months of gas predrainage, the residual gas content and the gas pressure at different points in the expected affected area decrease below the critical value. Changes in the residual gas content and gas pressure at these points are consistent with the apparent resistivity, which validates the rationality and feasibility of the multielectrode resistivity method in evaluating coal-seam hydraulic flushing.

  14. Hydraulic manipulator

    International Nuclear Information System (INIS)

    Sinha, A.K.; Srikrishnamurty, G.

    1990-01-01

    Successful operation of nuclear plant is largely dependent on safe handling of radio-active material. In order to reduce this handling problem and minimise the exposure of radiation, various handling equipment and manipulators have been developed according to the requirements. Manufacture of nuclear fuel, which is the most important part of the nuclear industry, involves handling of uranium ingots weighing approximately 250 kg. This paper describes a specially designed hydraulic manipulator for handling of the ingots in a limited space. It was designed to grab and handle the ingots in any position. This has following drive motions: (1)gripping and releasing, (2)lifting and lowering (z-motion), (3)rotation about the horizontal axis (azimuth drive), (4)rotation about the job axis, and (5)rotation about the vertical axis. For horizontal motion (X and Y axis motion) this equipment is mounted on a motorised trolley, so that it can move inside the workshop. For all drives except the rotation about the job axis, hydraulic cylinders have been used with a battery operated power pack. Trolley drive is also given power from same battery. This paper describes the design aspects of this manipulator. (author). 4 figs

  15. A numerical thermal-hydraulic model to simulate the fast transients in a supercritical water channel subjected to sharp pressure variations

    NARCIS (Netherlands)

    Dutta, G.; Jiang, J.; Maitri, R.; Zhang, C.

    2016-01-01

    The present work demonstrates the extension of a thermal-hydraulic model, THRUST, with an objective to simulate the fast transient flow dynamics in a supercritical water channel of circular cross section. THRUST is a 1-D model which solves the nonlinearly coupled mass, axial momentum and energy

  16. 底板巷水力冲孔卸压增透技术的研究与应用%Study and Application on Pressure Releasing and Permeability Improved Technology with Hydraulic Flushing in Floor Gateway

    Institute of Scientific and Technical Information of China (English)

    徐东方; 黄渊跃; 罗治顺; 杨献东

    2013-01-01

    In order to investigate the effect of the pressure releasing and permeability improved technology with hydraulic flushing in floor gateway to improve the seam permeability and to improve the gas drainage rate, a trial was conducted on the pressure releasing and permeability improved technology with hydraulic flushing in No. 1259(3) floor gateway of Puxijing.The results showed that the radius of the pressure releasing and permeability improvement with the hydraulic flushing borehole could reach 4~5 m and would be 1.6~2.0 times higher than the influence radius of the gas drainage with a conventional borehole. Within half month after the hydraulic flushing measures conducted, the average gas drainage concentration of the borehole was 2.77 times higher than the conventional borehole,the average gas flow value was 3.43 times higher than the conventional borehole,the effect of the pressure releasing and permeability improvement was relatively remarkable , the seam permeability was improved and the outburst danger was reduced.%为了考察底板巷水力冲孔卸压增透技术对增加煤层透气性,提高瓦斯抽采效果,在浦溪井1259(3)底板巷实施水力冲孔卸压增透技术试验.结果表明:水力冲孔卸压增透半径达到4~5m,为普通钻孔抽采影响半径的1.6~2.0倍;采取水力冲孔措施的半个月内,钻孔的平均瓦斯抽采浓度是普通钻孔的2.77倍,平均瓦斯流量是普通钻孔的3.43倍,卸压增透效果比较明显,提高了煤层透气性,降低了突出危险性.

  17. Undular Hydraulic Jump

    Directory of Open Access Journals (Sweden)

    Oscar Castro-Orgaz

    2015-04-01

    Full Text Available The transition from subcritical to supercritical flow when the inflow Froude number Fo is close to unity appears in the form of steady state waves called undular hydraulic jump. The characterization of the undular hydraulic jump is complex due to the existence of a non-hydrostatic pressure distribution that invalidates the gradually-varied flow theory, and supercritical shock waves. The objective of this work is to present a mathematical model for the undular hydraulic jump obtained from an approximate integration of the Reynolds equations for turbulent flow assuming that the Reynolds number R is high. Simple analytical solutions are presented to reveal the physics of the theory, and a numerical model is used to integrate the complete equations. The limit of application of the theory is discussed using a wave breaking condition for the inception of a surface roller. The validity of the mathematical predictions is critically assessed using physical data, thereby revealing aspects on which more research is needed

  18. Increased vapor pressure deficit due to higher temperature leads to greater transpiration and faster mortality during drought for tree seedlings common to the forest-grassland ecotone.

    Science.gov (United States)

    Will, Rodney E; Wilson, Stuart M; Zou, Chris B; Hennessey, Thomas C

    2013-10-01

    Tree species growing along the forest-grassland ecotone are near the moisture limit of their range. Small increases in temperature can increase vapor pressure deficit (VPD) which may increase tree water use and potentially hasten mortality during severe drought. We tested a 40% increase in VPD due to an increase in growing temperature from 30 to 33°C (constant dewpoint 21°C) on seedlings of 10 tree species common to the forest-grassland ecotone in the southern Great Plains, USA. Measurement at 33 vs 30°C during reciprocal leaf gas exchange measurements, that is, measurement of all seedlings at both growing temperatures, increased transpiration for seedlings grown at 30°C by 40% and 20% for seedlings grown at 33°C. Higher initial transpiration of seedlings in the 33°C growing temperature treatment resulted in more negative xylem water potentials and fewer days until transpiration decreased after watering was withheld. The seedlings grown at 33°C died 13% (average 2 d) sooner than seedlings grown at 30°C during terminal drought. If temperature and severity of droughts increase in the future, the forest-grassland ecotone could shift because low seedling survival rate may not sufficiently support forest regeneration and migration. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  19. Hydraulic testing in crystalline rock

    International Nuclear Information System (INIS)

    Almen, K.E.; Andersson, J.E.; Carlsson, L.; Hansson, K.; Larsson, N.A.

    1986-12-01

    Swedish Geolocical Company (SGAB) conducted and carried out single-hole hydraulic testing in borehole Fi 6 in the Finnsjoen area of central Sweden. The purpose was to make a comprehensive evaluation of different methods applicable in crystalline rocks and to recommend methods for use in current and scheduled investigations in a range of low hydraulic conductivity rocks. A total of eight different methods of testing were compared using the same equipment. This equipment was thoroughly tested as regards the elasticity of the packers and change in volume of the test section. The use of a hydraulically operated down-hole valve enabled all the tests to be conducted. Twelve different 3-m long sections were tested. The hydraulic conductivity calculated ranged from about 5x10 -14 m/s to 1x10 -6 m/s. The methods used were water injection under constant head and then at a constant rate-of-flow, each of which was followed by a pressure fall-off period. Water loss, pressure pulse, slug and drill stem tests were also performed. Interpretation was carried out using standard transient evaluation methods for flow in porous media. The methods used showed themselves to be best suited to specific conductivity ranges. Among the less time-consuming methods, water loss, slug and drill stem tests usually gave somewhat higher hydraulic conductivity values but still comparable to those obtained using the more time-consuming tests. These latter tests, however, provided supplementary information on hydraulic and physical properties and flow conditions, together with hydraulic conductivity values representing a larger volume of rock. (orig./HP)

  20. Toughness-Dominated Regime of Hydraulic Fracturing in Cohesionless Materials

    Science.gov (United States)

    Germanovich, L. N.; Hurt, R. S.; Ayoub, J.; Norman, W. D.

    2011-12-01

    experiments, there is a high pressure gradient in the leak-off zone in the direction normal to the fracture. Fluid pressure does not decrease considerably along the fracture, however, due to the relatively wide fracture aperture. This suggests that hydraulically induced fractures in unconsolidated materials may be considered to be within the toughness-dominated regime of hydraulic fracturing. Our results indicate that the primary influence on peak or initiation pressure comes from the remote stresses. However, fracture morphology changes significantly with other chosen parameters (stress, flow rate, rheology and permeability). Additionally, an important characteristic feature of fractures in our experiments is the frequent bluntness of the fracture tip, which suggests that plastic deformation at the fracture tip is important. Modeling shows that large openings at the fracture tip correspond to relatively large 'effective' fracture (surface) energy, which can be orders of magnitude greater than for typical (solid) rocks.

  1. Hydraulic Actuators with Autonomous Hydraulic Supply for the Mainline Aircrafts

    Directory of Open Access Journals (Sweden)

    I. S. Shumilov

    2014-01-01

    Full Text Available Applied in the aircraft control systems, hydraulic servo actuators with autonomous hydraulic supply, so-called, hydraulic actuators of integrated configuration, i.e. combination of a source of hydraulic power and its load in the single unit, are aimed at increasing control system reliability both owing to elimination of the pipelines connecting the actuator to the hydraulic supply source, and owing to avoidance of influence of other loads failure on the actuator operability. Their purpose is also to raise control system survivability by eliminating the long pipeline communications and their replacing for the electro-conductive power supply system, thus reducing the vulnerability of systems. The main reason for a delayed application of the hydraulic actuators in the cutting-edge aircrafts was that such aircrafts require hydraulic actuators of considerably higher power with considerable heat releases, which caused an unacceptable overheat of the hydraulic actuators. Positive and negative sides of the hydraulic actuators, their alternative options of increased reliability and survivability, local hydraulic systems as an advanced alternative to independent hydraulic actuators are considered.Now to use hydraulic actuators in mainline aircrafts is inexpedient since there are the unfairly large number of the problems reducing, first and last, safety of flights, with no essential weight and operational advantages. Still works to create competitive hydraulic actuators ought to be continued.Application of local hydraulic systems (LHS will allow us to reduce length of pressure head and drain pipelines and mass of pipelines, as well as to raise their general fail-safety and survivability. Application of the LHS principle will allow us to use a majority of steering drive advantages. It is necessary to allocate especially the following:- ease of meeting requirements for the non-local spread of the engine weight;- essentially reducing length and weight of

  2. Hydraulically centered control rod

    International Nuclear Information System (INIS)

    Horlacher, W.R.; Sampson, W.T.; Schukei, G.E.

    1981-01-01

    A control rod suspended to reciprocate in a guide tube of a nuclear fuel assembly has a hydraulic bearing formed at its lower tip. The bearing includes a plurality of discrete pockets on its outer surface into which a flow of liquid is continuously provided. In one embodiment the flow is induced by the pressure head in a downward facing chamber at the end of the bearing. In another embodiment the flow originates outside the guide tube. In both embodiments the flow into the pockets produces pressure differences across the bearing which counteract forces tending to drive the rod against the guide tube wall. Thus contact of the rod against the guide tube is avoided

  3. Fundamental study on thermo-hydraulic behaviors during power transient, 2

    International Nuclear Information System (INIS)

    Shinano, M.; Inoue, A.

    1988-01-01

    Thermo-hydraulic behaviors during power transient of nuclear reactors are studied. Boiling around test rod heated transiently forces to flow out liquid in the test section and generates high pressure pulse. In this study, it is investigated experimentally and analytically that magnitude of pressure pulse and energy conversion efficiency to the mechanical works in cases of fragmentation and non-fragmentation. In analysis, effects of increasing of heat transfer and of interaction area due to fragmentation is considered. Consequently, 1) magnitude of pressure pulse on fragmentation is about 10 times greater than that on non-fragmentation. 2) analytical model can show characteristics of fragmentation processes qualitatively. (author)

  4. Global Energy-Optimal Redundancy Resolution of Hydraulic Manipulators: Experimental Results for a Forestry Manipulator

    Directory of Open Access Journals (Sweden)

    Jarmo Nurmi

    2017-05-01

    Full Text Available This paper addresses the energy-inefficiency problem of four-degrees-of-freedom (4-DOF hydraulic manipulators through redundancy resolution in robotic closed-loop controlled applications. Because conventional methods typically are local and have poor performance for resolving redundancy with respect to minimum hydraulic energy consumption, global energy-optimal redundancy resolution is proposed at the valve-controlled actuator and hydraulic power system interaction level. The energy consumption of the widely popular valve-controlled load-sensing (LS and constant-pressure (CP systems is effectively minimised through cost functions formulated in a discrete-time dynamic programming (DP approach with minimum state representation. A prescribed end-effector path and important actuator constraints at the position, velocity and acceleration levels are also satisfied in the solution. Extensive field experiments performed on a forestry hydraulic manipulator demonstrate the performance of the proposed solution. Approximately 15–30% greater hydraulic energy consumption was observed with the conventional methods in the LS and CP systems. These results encourage energy-optimal redundancy resolution in future robotic applications of hydraulic manipulators.

  5. Plastic Foam Withstands Greater Temperatures And Pressures

    Science.gov (United States)

    Cranston, John A.; Macarthur, Doug

    1993-01-01

    Improved plastic foam suitable for use in foam-core laminated composite parts and in tooling for making fiber/matrix-composite parts. Stronger at high temperatures, more thermally and dimensionally stable, machinable, resistant to chemical degradation, and less expensive. Compatible with variety of matrix resins. Made of polyisocyanurate blown with carbon dioxide and has density of 12 to 15 pounds per cubic feet. Does not contibute to depletion of ozone from atmosphere. Improved foam used in cores of composite panels in such diverse products as aircraft, automobiles, railroad cars, boats, and sporting equipment like surfboards, skis, and skateboards. Also used in thermally stable flotation devices in submersible vehicles. Machined into mandrels upon which filaments wound to make shells.

  6. Evaluation of the effectiveness of the sealed double-ringed infiltrometers and the effects of changes in atmospheric pressure on hydraulic conductivity

    International Nuclear Information System (INIS)

    McMullin, S.R.

    1994-01-01

    The Savannah River Site (SRS) is currently evaluating some 40 hazardous and radioactive-waste sites for remediation. A remedial alternative under consideration is the closing of a waste site with a RCRA-style closure cap. The closure cap is a moisture barrier designed to inhibit the free flow of water downward into the buried wastes. When a remedial design is prepared, it is often necessary to test the cap materials to verify compliance with this recommended limit. Among the EPA-recommended test instruments is the sealed double-ring infiltrometer (SDRI). During recent testing at the Savannah River Site (SRS), six SDRI were installed and tested on a single kaolin clay cap. The purpose of this testing was to obtain a measure of the distribution of hydraulic conductivity across a model kaolin clay cap. The test results provide an evaluation of instrument performance and a measure of the repeatability of results. In addition, the testing identified variations in the unsaturated hydraulic conductivity. This paper presents an overview of the SDRI, the testing program at SRS, and an evaluation of the observations and test results

  7. Hydraulic Shearing and Hydraulic Jacking Observed during Hydraulic Stimulations in Fractured Geothermal Reservoir in Pohang, Korea

    Science.gov (United States)

    Min, K. B.; Park, S.; Xie, L.; Kim, K. I.; Yoo, H.; Kim, K. Y.; Choi, J.; Yoon, K. S.; Yoon, W. S.; Lee, T. J.; Song, Y.

    2017-12-01

    Enhanced Geothermal System (EGS) relies on sufficient and irreversible enhancement of reservoir permeability through hydraulic stimulation and possibility of such desirable change of permeability is an open question that can undermine the universality of EGS concept. We report results of first hydraulic stimulation campaign conducted in two deep boreholes in fractured granodiorite geothermal reservoir in Pohang, Korea. Borehole PX-1, located at 4.22 km, was subjected to the injection of 3,907 m3 with flow rate of up to 18 kg/s followed by bleeding off of 1,207 m3. The borehole PX-2, located at 4.35 km, was subjected to the injection of 1,970 m3 with flow rate of up to 46 kg/sIn PX-1, a sharp distinct decline of wellhead pressure was observed at around 16 MPa of wellhead pressure which was similar to the predicted injection pressure to induce hydraulic shearing. Injectivity interpretation before and after the hydraulic shearing indicates that permanent increase of permeability was achieved by a factor of a few. In PX-2, however, injectivity was very small and hydraulic shearing was not observed due possibly to the near wellbore damage made by the remedying process of lost circulation such as using lost circulation material during drilling. Flow rate of larger than 40 kg/s was achieved at very high well head pressure of nearly 90 MPa. Hydraulic jacking, that is reversible opening and closure of fracture with change of injection pressure, was clearly observed. Although sharp increase of permeability due to fracture opening was achieved with elevated injection pressure, the increased permeability was reversed with decreased injection pressure.Two contrasting response observed in the same reservoir at two different boreholes which is apart only 600 m apart provide important implication that can be used for the stimulation strategy for EGS.This work was supported by the New and Renewable Energy Technology Development Program of the Korea Institute of Energy Technology

  8. Hydraulic release oil tool

    International Nuclear Information System (INIS)

    Mims, M.G.; Mueller, M.D.; Ehlinger, J.C.

    1992-01-01

    This patent describes a hydraulic release tool. It comprises a setting assembly; a coupling member for coupling to drill string or petroleum production components, the coupling member being a plurality of sockets for receiving the dogs in the extended position and attaching the coupling member the setting assembly; whereby the setting assembly couples to the coupling member by engagement of the dogs in the sockets of releases from and disengages the coupling member in movement of the piston from its setting to its reposition in response to a pressure in the body in exceeding the predetermined pressure; and a relief port from outside the body into its bore and means to prevent communication between the relief port and the bore of the body axially of the piston when the piston is in the setting position and to establish such communication upon movement of the piston from the setting position to the release position and reduce the pressure in the body bore axially of the piston, whereby the reduction of the pressure signals that the tool has released the coupling member

  9. System Design and Performance Test of Hydraulic Intensifier

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyoung Eui; Lee, Gi Chun [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Kim, Jae Hoon [Chungnam National University, Daejeon (Korea, Republic of)

    2010-07-15

    Components such as pressure vessel, hydraulic hose assembly, accumulator, hydraulic cylinder, hydraulic valve, pipe, etc., are tested under the impulse-pressure conditions prescribed in ISO and SAE standards. The impulse pressure test machine needs to have a high pressure, a precise control system and a long life. It should satisfy the requirements for fabrication of the impulse tester to generate ultra high pressure in the hydraulic system. In the impulse tester, a servo-valve control system is adopted; although the control application is convenient, it is expensive owing to the cost of developing the system. The type of the control system determines the pressure wave, which affects the components that are tested. In this study, the manufacturing process and the intensifier system design related to the flow, pressure, and the increasing rate of pressure are investigated. The results indicate the ultra high pressure waves in the system.

  10. Influence of Hydraulic Design on Stability and on Pressure Pulsations in Francis Turbines at Overload, Part Load and Deep Part Load based on Numerical Simulations and Experimental Model Test Results

    International Nuclear Information System (INIS)

    Magnoli, M V; Maiwald, M

    2014-01-01

    Francis turbines have been running more and more frequently in part load conditions, in order to satisfy the new market requirements for more dynamic and flexible energy generation, ancillary services and grid regulation. The turbines should be able to be operated for longer durations with flows below the optimum point, going from part load to deep part load and even speed-no-load. These operating conditions are characterised by important unsteady flow phenomena taking place at the draft tube cone and in the runner channels, in the respective cases of part load and deep part load. The current expectations are that new Francis turbines present appropriate hydraulic stability and moderate pressure pulsations at overload, part load, deep part load and speed-no-load with high efficiency levels at normal operating range. This study presents series of investigations performed by Voith Hydro with the objective to improve the hydraulic stability of Francis turbines at overload, part load and deep part load, reduce pressure pulsations and enlarge the know-how about the transient fluid flow through the turbine at these challenging conditions. Model test measurements showed that distinct runner designs were able to influence the pressure pulsation level in the machine. Extensive experimental investigations focused on the runner deflector geometry, on runner features and how they could reduce the pressure oscillation level. The impact of design variants and machine configurations on the vortex rope at the draft tube cone at overload and part load and on the runner channel vortex at deep part load were experimentally observed and evaluated based on the measured pressure pulsation amplitudes. Numerical investigations were employed for improving the understanding of such dynamic fluid flow effects. As example for the design and experimental investigations, model test observations and pressure pulsation curves for Francis machines in mid specific speed range, around n qopt = 50

  11. 高压水力压裂和二氧化碳相变致裂联合增透技术%Combined permeability improved technology with high pressure hydraulic fracturing and carbon dioxide phase change cracking

    Institute of Scientific and Technical Information of China (English)

    秦江涛; 陈玉涛; 黄文祥

    2017-01-01

    针对白皎煤矿地质构造复杂、构造应力大、煤层透气性差、抽采瓦斯效果差的问题,提出了高压水力压裂和二氧化碳相变致裂联合增透技术,分析了水力压裂和二氧化碳相变致裂联合增透技术的原理;并在238底板巷对B4煤层进行了联合增透对比试验研究.试验结果表明:试验区域煤层透气性显著提高,单孔初抽瓦斯体积分数分别是高压水力压裂试验区域和普通抽采试验区域平均瓦斯体积分数的1.70、3.48倍;瓦斯抽采纯量较水力压裂区域和普通抽采区域分别提高了1.49、3.04倍;抽采65 d以后,高压水力压裂和二氧化碳相变致裂联合增透区域汇总瓦斯体积分数仍保持在40%以上,抽采效果良好,该技术可供类似矿井借鉴.%According to the problems of complicated geological tectonics,high tectonic stress,poor seam permeability and poor gas drainage effect in Baijiao Mine,a permeability improved technology combined with a high pressure hydraulic fracturing and carbon dioxide phase change cracking was provided and the principle of the hydraulic fracturing and carbon dioxide combined permeability improved technology was analyzed.A comparison experiment study was conducted on the combined permeability improvement of No.B4 Seam in No.238 floor gateway.The experiment results showed that the permeability of the seam in the technical experiment area was remarkably improved and the initial drained gas volume fraction of a single borehole was 1.70 times and 3.48 times higher than the average volume fractions of the high pressure hydraulic fracturing area and the conventional gas drainage trial area individually.The gas drainage pure volume was improved by 1.49 and 3.04 times higher than the hydraulic fracturing area and the conventional gas drainage area individually.After 65 days of the gas drainage operation,the total gas volume fraction of the high pressure hydraulic fracturing and carbon dioxide phase change

  12. Hydraulics calculation in drilling simulator

    Science.gov (United States)

    Malyugin, Aleksey A.; Kazunin, Dmitry V.

    2018-05-01

    The modeling of drilling hydraulics in the simulator system is discussed. This model is based on the previously developed quasi-steady model of an incompressible fluid flow. The model simulates the operation of all parts of the hydraulic drilling system. Based on the principles of creating a common hydraulic model, a set of new elements for well hydraulics was developed. It includes elements that correspond to the in-drillstring and annular space. There are elements controlling the inflow from the reservoir into the well and simulating the lift of gas along the annulus. New elements of the hydrosystem take into account the changing geometry of the well, loss in the bit, characteristics of the fluids including viscoplasticity. There is an opportunity specify the complications, the main one of which is gas, oil and water inflow. Correct work of models in cases of complications makes it possible to work out various methods for their elimination. The coefficients of the model are adjusted on the basis of incomplete experimental data provided by operators of drilling platforms. At the end of the article the results of modeling the elimination of gas inflow by a continuous method are presented. The values displayed in the simulator (drill pipe pressure, annulus pressure, input and output flow rates) are in good agreement with the experimental data. This exercise took one hour, which is less than the time on a real rig with the same configuration of equipment and well.

  13. Hydraulic Design Criteria for Spacer Grids of Nuclear Fuel Element

    International Nuclear Information System (INIS)

    Juanico, Luis; Brasnarof, Daniel

    2000-01-01

    In this paper a hydraulic model for calculating the pressure drop on the CARA spacer grids is extended.This model is validated and feedback from experimental hydraulic test performed in a low pressure loop.The importance of the spacer grid geometric parameter (that is, its thickness and length, the number and kind of their fix spacer), developing hydraulic design criteria for spacer grid on fuel element

  14. One-dimensional analysis of the hydrodynamic and thermal characteristics of thin film flows including the hydraulic jump and rotation

    Science.gov (United States)

    Thomas, S.; Hankey, W.; Faghri, A.; Swanson, T.

    1990-01-01

    The flow of a thin liquid film with a free surface along a horizontal plane that emanates from a pressurized vessel is examined numerically. In one g, a hydraulic jump was predicted in both plane and radial flow, which could be forced away from the inlet by increasing the inlet Froude number or Reynolds number. In zero g, the hydraulic jump was not predicted. The effect of solid-body rotation for radial flow in one g was to 'wash out' the hydraulic jump and to decrease the film height on the disk. The liquid film heights under one g and zero g were equal under solid-body rotation because the effect of centrifugal force was much greater than that of the gravitational force. The heat transfer to a film on a rotating disk was predicted to be greater than that of a stationary disk because the liquid film is extremely thin and is moving with a very high velocity.

  15. Hydraulic system for driving control rods

    International Nuclear Information System (INIS)

    Okuzumi, Naoaki.

    1982-01-01

    Purpose: To enable safety reactor shut down upon occurrence of an abnormal excess pressure in a hydraulic control unit. Constitution: The actuation pressure for a pressure switch that generates a scram signal is set lower than the release pressure set to a pressure release valve. Thus, if the pressure of nitrogen gas in a nitrogen container increases such as upon exposure of the hydraulic control unit to a high temperature, the pressure switch is actuated at first to generate the scram signal and a scram valve is opened to supply water at high pressure to control rod drives under the driving force of the nitrogen gas at high pressure to rapidly insert the control element into the reactor and shut down it. If the pressure of the nitrogen gas still increases after the scram, the pressure release valve is opened to release the nitrogen gas at high temperature to the atmosphere. Since the scram is attained before the actuation of the pressure release valve, safety reactor shut down can be attained and the hydraulic control unit can be protected. (Sekiya, K.)

  16. Hydraulic regenerative system for a light vehicle

    OpenAIRE

    Orpella Aceret, Jordi; Guinart Trayter, Xavier

    2009-01-01

    The thesis is based in a constructed light vehicle that must be improved by adding a hydraulic energy recovery system. This vehicle named as TrecoLiTH, participated in the Formula Electric and Hybrid competition (Formula EHI) 2009 in Italy -Rome- and won several awards. This system consists in two hydraulic motors hub mounted which are used to store fluid at high pressure in an accumulator when braking. Through a valve the pressure will flow from the high pressure accumulator to the low press...

  17. Advantages of Oscillatory Hydraulic Tomography

    Science.gov (United States)

    Kitanidis, P. K.; Bakhos, T.; Cardiff, M. A.; Barrash, W.

    2012-12-01

    Characterizing the subsurface is significant for most hydrogeologic studies, such as those involving site remediation and groundwater resource explo¬ration. A variety of hydraulic and geophysical methods have been developed to estimate hydraulic conductivity and specific storage. Hydraulic methods based on the analysis of conventional pumping tests allow the estimation of conductivity and storage without need for approximate petrophysical relations, which is an advantage over most geophysical methods that first estimate other properties and then infer values of hydraulic parameters. However, hydraulic methods have the disadvantage that the head-change signal decays with distance from the pumping well and thus becomes difficult to separate from noise except in close proximity to the source. Oscillatory hydraulic tomography (OHT) is an emerging technology to im¬age the subsurface. This method utilizes the idea of imposing sinusoidally varying pressure or discharge signals at several points, collecting head observations at several other points, and then processing these data in a tomographic fashion to estimate conductivity and storage coefficients. After an overview of the methodology, including a description of the most important potential advantages and challenges associated with this approach, two key promising features of the approach will be discussed. First, the signal at an observation point is orthogonal to and thus can be separated from nuisance inputs like head fluctuation from production wells, evapotranspiration, irrigation, and changes in the level of adjacent streams. Second, although the signal amplitude may be weak, one can extract the phase and amplitude of the os¬cillatory signal by collecting measurements over a longer time, thus compensating for the effect of large distance through longer sampling period.

  18. Hydraulic Hybrid Vehicles

    Science.gov (United States)

    EPA and the United Parcel Service (UPS) have developed a hydraulic hybrid delivery vehicle to explore and demonstrate the environmental benefits of the hydraulic hybrid for urban pick-up and delivery fleets.

  19. Control rod driving hydraulic device

    International Nuclear Information System (INIS)

    Sugano, Hiroshi.

    1993-01-01

    In a control rod driving hydraulic device for an improved BWR type reactor, a bypass pipeline is disposed being branched from a scram pipeline, and a control orifice and a throttle valve are interposed to the bypass pipeline for restricting pressure. Upon occurrence of scram, about 1/2 of water quantity flowing from an accumulator of a hydraulic control unit to the lower surface of a piston of control rod drives by way of a scram pipeline is controlled by the restricting orifice and the throttle valve, by which the water is discharged to a pump suction pipeline or other pipelines by way of the bypass pipeline. With such procedures, a function capable of simultaneously conducting scram for two control rod drives can be attained by one hydraulic control unit. Further, an excessive peak pressure generated by a water hammer phenomenon in the scram pipeline or the control rod drives upon occurrence of scram can be reduced. Deformation and failure due to the excessive peak pressure can be prevented, as well as vibrations and degradation of performance of relevant portions can be prevented. (N.H.)

  20. Characteristics of Air Entrainment in Hydraulic Jump

    Science.gov (United States)

    Albarkani, M. S. S.; Tan, L. W.; Al-Gheethi, A.

    2018-04-01

    The characteristics of hydraulic jump, especially the air entrainment within jump is still not properly understood. Therefore, the current work aimed to determine the size and number of air entrainment formed in hydraulic jump at three different Froude numbers and to obtain the relationship between Froude number with the size and number of air entrainment in hydraulic jump. Experiments of hydraulic jump were conducted in a 10 m long and 0.3 m wide Armfield S6MKII glass-sided tilting flume. Hydraulic jumps were produced by flow under sluice gate with varying Froude number. The air entrainment of the hydraulic jump was captured with a Canon Power Shot SX40 HS digital camera in video format at 24 frames per second. Three discharges have been considered, i.e. 0.010 m3/s, 0.011 m3/s, and 0.013 m3/s. For hydraulic jump formed in each discharge, 32 frames were selected for the purpose of analysing the size and number of air entrainment in hydraulic jump. The results revealed that that there is a tendency to have greater range in sizes of air bubbles as Fr1 increases. Experiments with Fr1 = 7.547. 7.707, and 7.924 shown that the number of air bubbles increases exponentially with Fr1 at a relationship of N = 1.3814 e 0.9795Fr1.

  1. Hydraulics and pneumatics a technician's and engineer's guide

    CERN Document Server

    Parr, Andrew

    1991-01-01

    Hydraulics and Pneumatics: A Technician's and Engineer's Guide provides an introduction to the components and operation of a hydraulic or pneumatic system. This book discusses the main advantages and disadvantages of pneumatic or hydraulic systems.Organized into eight chapters, this book begins with an overview of industrial prime movers. This text then examines the three different types of positive displacement pump used in hydraulic systems, namely, gear pumps, vane pumps, and piston pumps. Other chapters consider the pressure in a hydraulic system, which can be quickly and easily controlled

  2. Optimization of hydraulic turbine diffuser

    Directory of Open Access Journals (Sweden)

    Moravec Prokop

    2016-01-01

    Full Text Available Hydraulic turbine diffuser recovers pressure energy from residual kinetic energy on turbine runner outlet. Efficiency of this process is especially important for high specific speed turbines, where almost 50% of available head is utilized within diffuser. Magnitude of the coefficient of pressure recovery can be significantly influenced by designing its proper shape. Present paper focuses on mathematical shape optimization method coupled with CFD. First method is based on direct search Nelder-Mead algorithm, while the second method employs adjoint solver and morphing. Results obtained with both methods are discussed and their advantages/disadvantages summarized.

  3. An evaluation of calculation procedures affecting the constituent factors of equivalent circulating density for drilling hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, William J

    1997-12-31

    This Dr. ing. thesis covers a study of drilling hydraulics offshore. The purpose of drilling hydraulics is to provide information about downhole pressure, suitable surface pump rates, the quality of hole cleaning and optimum tripping speeds during drilling operations. Main fields covered are drilling hydraulics, fluid characterisation, pressure losses, and equivalent circulating density. 197 refs., 23 figs., 22 tabs.

  4. An evaluation of calculation procedures affecting the constituent factors of equivalent circulating density for drilling hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, William J.

    1996-12-31

    This Dr. ing. thesis covers a study of drilling hydraulics offshore. The purpose of drilling hydraulics is to provide information about downhole pressure, suitable surface pump rates, the quality of hole cleaning and optimum tripping speeds during drilling operations. Main fields covered are drilling hydraulics, fluid characterisation, pressure losses, and equivalent circulating density. 197 refs., 23 figs., 22 tabs.

  5. Variation of Desert Soil Hydraulic Properties with Pedogenic Maturity

    Science.gov (United States)

    Nimmo, J. R.; Perkins, K. S.; Mirus, B. B.; Schmidt, K. M.; Miller, D. M.; Stock, J. D.; Singha, K.

    2006-12-01

    Older alluvial desert soils exhibit greater pedogenic maturity, having more distinct desert pavements, vesicular (Av) horizons, and more pronounced stratification from processes such as illuviation and salt accumulation. These and related effects strongly influence the soil hydraulic properties. Older soils have been observed to have lower saturated hydraulic conductivity, and possibly greater capacity to retain water, but the quantitative effect of specific pedogenic features on the soil water retention or unsaturated hydraulic conductivity (K) curves is poorly known. With field infiltration/redistribution experiments on three different-aged soils developed within alluvial wash deposits in the Mojave National Preserve, we evaluated effective hydraulic properties over a scale of several m horizontally and to 1.5 m depth. We then correlated these properties with pedogenic features. The selected soils are (1) recently deposited sediments, (2) a soil of early Holocene age, and (3) a highly developed soil of late Pleistocene age. In each experiment we ponded water in a 1-m-diameter infiltration ring for 2.3 hr. For several weeks we monitored subsurface water content and matric pressure using surface electrical resistance imaging, dielectric-constant probes, heat-dissipation probes, and tensiometers. Analysis of these data using an inverse modeling technique gives the water retention and K properties needed for predictive modeling. Some properties show a consistent trend with soil age. Progressively more developed surface and near-surface features such as desert pavement and Av horizons are the likely cause of an observed consistent decline of infiltration capacity with soil age. Other properties, such as vertical flow retardation by layer contrasts, appear to have a more complicated soil-age dependence. The wash deposits display distinct depositional layering that has a retarding effect on vertical flow, an effect that may be less pronounced in the older Holocene soil

  6. Comparative study of methods to estimate hydraulic parameters in the hydraulically undisturbed Opalinus Clay (Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.; Matray, J.-M. [Institut de Radioprotection et de Sûreté Nucléaire, Fontenay-aux-Roses, (France); Yu, C.; Gonçalvès, J. [Aix Marseille Université UMR 6635 CEREGE Technopôle Environnement Arbois-Méditerranée Aix-en-Provence, Cedex 4 (France); and others

    2017-04-15

    The deep borehole (DB) experiment gave the opportunity to acquire hydraulic parameters in a hydraulically undisturbed zone of the Opalinus Clay at the Mont Terri rock laboratory (Switzerland). Three methods were used to estimate hydraulic conductivity and specific storage values of the Opalinus Clay formation and its bounding formations through the 248 m deep borehole BDB-1: application of a Poiseuille-type law involving petrophysical measurements, spectral analysis of pressure time series and in situ hydraulic tests. The hydraulic conductivity range in the Opalinus Clay given by the first method is 2 × 10{sup -14}-6 × 10{sup -13} m s{sup -1} for a cementation factor ranging between 2 and 3. These results show low vertical variability whereas in situ hydraulic tests suggest higher values up to 7 × 10{sup -12} m s{sup -1}. Core analysis provides economical estimates of the homogeneous matrix hydraulic properties but do not account for heterogeneities at larger scale such as potential tectonic conductive features. Specific storage values obtained by spectral analysis are consistent and in the order of 10{sup -6} m{sup -1}, while formulations using phase shift and gain between pore pressure signals were found to be inappropriate to evaluate hydraulic conductivity in the Opalinus Clay. The values obtained are globally in good agreement with the ones obtained previously at the rock laboratory. (authors)

  7. Report of the experts' mission to review thermal hydraulic and structural analyses for PTS assessment of Kozloduy NPP units 1-4 reactor pressure vessels, Sofia, Bulgaria 3-7 April 1995

    International Nuclear Information System (INIS)

    1995-01-01

    Based upon a request of the Government of Bulgaria and in order to assist its Regulatory Body, an experts' mission was carried out to Sofia and Kozloduy, 21-25 November 1994 within the framework of the IAEA TC Project BUL/9/013-05 and of the IAEA Extrabudgetary Programme on the Safety of the WWER NPPs. The mission also specified the technical content of further assistance by the IAEA. With respect to the findings and recommendations made in November 1994, WWER-SC-109, a follow-up expert's mission was carried out to Sofia, Bulgaria, April 3-7, 1995. The objective of the mission was to review the selection of transients, thermal hydraulic, stress and fracture mechanics analyses for reactor pressure vessel integrity assessment of Kozloduy unit 1-4. In addition, an update on the activities completed, underway and planned related to unit 1 reactor pressure vessel embrittlement was presented and discussed. The review was carried out by 4 international experts from Finland, France, Russia and IAEA in co-operation with the Bulgarian regulatory body, plant, Energoproject Sofia and Institute of Metals staff. The mission was conducted out within the frame of the IAEA TC Project BUL/9/013-05 and of the IAEA Extrabudgetary Programme on the Safety of the WWER NPPs. 18 refs

  8. Horizontal steam generator thermal-hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O. [SKODA Praha Company, Prague (Czechoslovakia); Doubek, M. [Czech Technical Univ., Prague (Czechoslovakia)

    1995-09-01

    Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. The 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.

  9. Parametric Assessment of Perchloroethylene Hydraulic Behaviour in a Two-Phase System

    International Nuclear Information System (INIS)

    Chatrenour, M.; Homaee, M.; Asadi Kapourchal, S.; Mahmoodian Shoshtari, M.

    2016-01-01

    Quantitative description of soil hydraulic properties is crucial for preventing organic contamination entering into the soil and groundwater. In order to assess the hydraulic behaviour of Perchloroethylene as a toxic chlorinated contaminant in soil, the retention curves for Perchloroethylene and water were determined. The Saturated hydraulic conductivity of both fluids examined was determined by the constant head method. The Perchloroethylene and water hydraulic conductivities obtained were 492.84 and 450.27 cm day-1, respectively. The porous medium retention parameters were obtained based on the van Genuchten, Brooks-Corey and Kosugi retention models. Further, the unsaturated hydraulic conductivity for both fluids was obtained based on the Mualem-Brooks-Corey, Mualem-van Genuchten and Mualem-Kosugi models. The accuracy performance of the models was assessed using some statistics including ME, RMSE, EF, CD and CRM. Results indicated that the van Genuchten model provided better estimations than other models when the fluid studied was Perchloroethylene. The results further indicated that the magnitudes of the pore-size distribution parameters and the bubbling pressure parameters are reduced more in a water-air system compared to a Perchloroethylene-air system. This can be attributed to the high viscosity of water and its considerable resistance against flow. This implies that more suction is needed to drain water out from a porous medium than Perchloroethylene. Consequently, a porous medium provides less retention for Perchloroethylene at a given quantity of fluid than water. Owing to lower Perchloroethylene viscosity, the saturated and unsaturated porous medium hydraulic conductivity of Perchloroethylene was greater than that of water. Since Perchloroethylene has lower retention and larger hydraulic conductivity than water, its infiltration into a porous medium would lead to its faster movement towards groundwater.

  10. Model for polygonal hydraulic jumps

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Watanabe, Shinya; Bohr, Tomas

    2012-01-01

    We propose a phenomenological model for the polygonal hydraulic jumps discovered by Ellegaard and co-workers [Nature (London) 392, 767 (1998); Nonlinearity 12, 1 (1999); Physica B 228, 1 (1996)], based on the known flow structure for the type-II hydraulic jumps with a "roller" (separation eddy...... nonhydrostatic pressure contributions from surface tension in light of recent observations by Bush and co-workers [J. Fluid Mech. 558, 33 (2006); Phys. Fluids 16, S4 (2004)]. The model can be analyzed by linearization around the circular state, resulting in a parameter relationship for nearly circular polygonal...... states. A truncated but fully nonlinear version of the model can be solved analytically. This simpler model gives rise to polygonal shapes that are very similar to those observed in experiments, even though surface tension is neglected, and the condition for the existence of a polygon with N corners...

  11. Analysis of buffering process of control rod hydraulic absorber

    International Nuclear Information System (INIS)

    Bao Jishi; Qin Benke; Bo Hanliang

    2011-01-01

    Control Rod Hydraulic Drive Mechanism(CRHDM) is a newly invented build-in control rod drive mechanism. Hydraulic absorber is the key part of this mechanism, and is used to cushion the control rod when the rod scrams. Thus, it prevents the control rod from being deformed and damaged. In this paper dynamics program ANSYS CFX is used to calculate all kinds of flow conditions in hydraulic absorber to obtain its hydraulic characteristics. Based on the flow resistance coefficients obtained from the simulation results, fluid mass and momentum equations were developed to get the trend of pressure change in the hydraulic cylinder and the displacement of the piston rod during the buffering process of the control rod. The results obtained in this paper indicate that the hydraulic absorber meets the design requirement. The work in this paper will be helpful for the design and optimization of the control rod hydraulic absorber. (author)

  12. Advanced energy saving hydraulic elevator

    Energy Technology Data Exchange (ETDEWEB)

    Garrido, A.; Sevilleja, J.; Servia, A.

    1993-08-24

    An hydraulic elevator is described comprising: a counterweighted elevator comprising a car, a counterweight, and a rope connecting the car and the counterweight; a ram having a first reaction surface for driving one of the car or the counterweight upwardly and a second reaction surface for driving one of the car or the counterweight downwardly; multiplier means for moving the car a distance greater than a stroke of the ram, the multiplier means connecting the ram to the counterweighted elevator, the multiplier means comprising: a first pulley; a second pulley; means for rigidly connecting the first and second pulley, the means having a length corresponding to a rise of the hydraulic elevator, the means attaching to the ram; and a pulley rope which: has a first end attaching to a first fixed point, extends about the first pulley, extends about the second pulley, and has a second end attaching to a second fixed point.

  13. Hydraulic modelling of the CARA Fuel element

    International Nuclear Information System (INIS)

    Brasnarof, Daniel O.; Juanico, Luis; Giorgi, M.; Ghiselli, Alberto M.; Zampach, Ruben; Fiori, Jose M.; Yedros, Pablo A.

    2004-01-01

    The CARA fuel element is been developing by the National Atomic Energy Commission for both Argentinean PHWRs. In order to keep the hydraulic restriction in their fuel channels, one of CARA's goals is to keep its similarity with both present fuel elements. In this paper is presented pressure drop test performed at a low-pressure facility (Reynolds numbers between 5x10 4 and 1,5x10 5 ) and rational base models for their spacer grid and rod assembly. Using these models, we could estimate the CARA hydraulic performance in reactor conditions that have shown to be satisfactory. (author) [es

  14. Tissue perfusion during normovolemic hemodilution investigated by a hydraulic model of the cardiovascular system.

    Science.gov (United States)

    Mirhashemi, S; Messmer, K; Intaglietta, M

    1987-01-01

    Normovolemic hemodilution on a whole body basis is studied by means of a steady flow, hydraulic analogue simulation of the cardiovascular system, based on the Casson's model and current hemodynamic and rheological data. The vasculature is divided into serially connected compartments whose hydraulic resistance is characterized by the average diameter, length, number of vessels, and the corresponding rheological properties of blood formulated by Dintenfass (1971) and Lipowsky et al. (1980). This model computes the pressure distributions in all compartments, where the calculated venous pressure modulates the cardiac function according to the Starling mechanism for cardiac performance. The alterations of flow induced by the action of the heart are added to the effects due to changes in peripheral vascular resistance as a result of hematocrit variation. This model shows that when the response of heart to the changes of venous pressure is impaired, the maximum oxygen carrying capacity occurs at 40% hematocrit (H) where it is 1% higher than normal hematocrit (H = 44%). The normal cardiac response to the changes of venous pressure, causes the maximum oxygen carrying capacity to occur at 32% H where it is 12% greater than that at normal hematocrit. Mean arteriolar pressure and capillary pressure increase while venular pressure is slightly reduced during normovolemic hemodilution.

  15. Self-potential observations during hydraulic fracturing

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Jeffrey R.; Glaser, Steven D.

    2007-09-13

    The self-potential (SP) response during hydraulic fracturing of intact Sierra granite was investigated in the laboratory. Excellent correlation of pressure drop and SP suggests that the SP response is created primarily by electrokinetic coupling. For low pressures, the variation of SP with pressure drop is linear, indicating a constant coupling coefficient (Cc) of -200 mV/MPa. However for pressure drops >2 MPa, the magnitude of the Cc increases by 80% in an exponential trend. This increasing Cc is related to increasing permeability at high pore pressures caused by dilatancy of micro-cracks, and is explained by a decrease in the hydraulic tortuosity. Resistivity measurements reveal a decrease of 2% prior to hydraulic fracturing and a decrease of {approx}35% after fracturing. An asymmetric spatial SP response created by injectate diffusion into dilatant zones is observed prior to hydraulic fracturing, and in most cases this SP variation revealed the impending crack geometry seconds before failure. At rupture, injectate rushes into the new fracture area where the zeta potential is different than in the rock porosity, and an anomalous SP spike is observed. After fracturing, the spatial SP distribution reveals the direction of fracture propagation. Finally, during tensile cracking in a point load device with no water flow, a SP spike is observed that is caused by contact electrification. However, the time constant of this event is much less than that for transients observed during hydraulic fracturing, suggesting that SP created solely from material fracture does not contribute to the SP response during hydraulic fracturing.

  16. Hydraulic characterization of " Furcraea andina

    Science.gov (United States)

    Rivera-Velasquez, M. F.; Fallico, C.; Molinari, A.; Santillan, P.; Salazar, M.

    2012-04-01

    constant head we repeated the test for three different rate of fiber compaction within the flow cell, corresponding to three different densities (146 kg/m3, 200 kg/m3 and 240 kg/m3). We observed that with increasing density of the fibers there is an increase of hydraulic conductivity. The importance of the experimental results on permeability acquires greater relevance when compared to the values of hydraulic conductivity already known from the literature for different soils types. In this study, special attention has been given to the value of hydraulic conductivity of this fiber, considering that in the framework of groundwater remediation strategies if the hydraulic conductivity in the barrier is lower than that of the surrounding aquifer, the plume may change its natural pathway, bypassing the barrier and veering towards larger hydraulic conductivity. Reference • Lee, B. G. and Rowell, R. M.: Removal of heavy metal ions from aqueous solutions using lignocellulosic fibers, J. Natural Fibers, 1, 97-108, 2004. • Troisi, S., Fallico, C., Straface, S., and Mazzuca, L.: Biodreni per la bonifica di siti contaminati realizzati con fibre naturali liberiane ad elevato sviluppo superficiale. Brevetto dell'Università della Calabria (n.: CS2008A00018), 2008. • C. Fallico, S. Troisi, A. Molinari, and M. F. Rivera.: Characterization of broom fibers for PRB in the remediation of aquifers contaminated by heavy metals, Biogeosciences journal , 7, 2545-2556, 2010

  17. Modified hydraulic braking system limits angular deceleration to safe values

    Science.gov (United States)

    Briggs, R. S.; Council, M.; Green, P. M.

    1966-01-01

    Conventional spring actuated, hydraulically released, fail-safe disk braking system is modified to control the angular deceleration of a massive antenna. The hydraulic system provides an immediate preset pressure to the spring-loaded brake shoes and holds it at this value to decelerate the antenna at the desired rate.

  18. Design, manufacture and performance research of double acting hydraulic press

    OpenAIRE

    Koc, Erdem; Unver, Ertu; Ozturk, Hidayet

    1990-01-01

    This research presents the design and production of a double acting 40 tons capacity hydraulic press. The issues in the design, engineering manufacturing of the hydraulic press are reported specifically on both cylinders generating the same pressure and velocity using a solenoid directional control valve and a flow separating valve. (In Turkish)

  19. Vegetation-zonation patterns across a temperate mountain cloud forest ecotone are not explained by variation in hydraulic functioning or water relations.

    Science.gov (United States)

    Berry, Z Carter; Johnson, Daniel M; Reinhardt, Keith

    2015-09-01

    Many studies have demonstrated linkages between the occurrence of fog and ecophysiological functioning in cloud forests, but few have investigated hydraulic functioning as a determining factor that explains sharp changes in vegetation. The objective of this study was to compare the plant water status during cloud-immersed and non-immersed conditions and hydraulic vulnerability in branches and roots of species across a temperate, mountain fog ecotone. Because cloud forests are often dark, cool and very moist, we expected cloud forest species to have less drought-tolerant characteristics (i.e., lower Pe and P50-the pressures required to induce a 12 and 50% loss in hydraulic conductivity, respectively) relative to non-cloud forest species in adjacent (lower elevation) forests. Additionally, due to the ability of cloud forest species to absorb cloud-fog water, we predicted greater improvements in hydraulic functioning during fog in cloud forest species relative to non-cloud forest species. Across the cloud forest ecotone, most species measured were very resistant to losses in conductivity with branch P50 values from -4.5 to -6.0 MPa, hydraulic safety margins (Ψmin - P50) >1.5 MPa and low calculated hydraulic conductivity losses. Roots had greater vulnerabilities, with P50 values ranging from -1.4 to -2.5 MPa, leading to greater predicted losses in conductivity (∼20%). Calculated values suggested strong losses of midday leaf hydraulic conductance in three of the four species, supporting the hydraulic segmentation hypothesis. In both cloud forest and hardwood species, Ψs were greater on foggy days than sunny days, demonstrating the importance of fog periods to plant water balance across fog regimes. Thus, frequent fog did not result in systemic changes in hydraulic functioning or vulnerability to embolism across our temperate cloud forest ecotone. Finally, roots functioned with lower hydraulic conductivity than branches, suggesting that they may serve as more

  20. Digital switched hydraulics

    Science.gov (United States)

    Pan, Min; Plummer, Andrew

    2018-06-01

    This paper reviews recent developments in digital switched hydraulics particularly the switched inertance hydraulic systems (SIHSs). The performance of SIHSs is presented in brief with a discussion of several possible configurations and control strategies. The soft switching technology and high-speed switching valve design techniques are discussed. Challenges and recommendations are given based on the current research achievements.

  1. Hydraulic Structures : Caissons

    NARCIS (Netherlands)

    Voorendt, M.Z.; Molenaar, W.F.; Bezuyen, K.G.

    These lecture notes on caissons are part of the study material belonging to the course 'Hydraulic Structures 1' (code CTB3355), part of the Bachelor of Science education and the Hydraulic Engineering track of the Master of Science education for civil engineering students at Delft University of

  2. Greater autonomy at work

    NARCIS (Netherlands)

    Houtman, I.L.D.

    2004-01-01

    In the past 10 years, workers in the Netherlands increasingly report more decision-making power in their work. This is important for an economy in recession and where workers face greater work demands. It makes work more interesting, creates a healthier work environment, and provides opportunities

  3. Handbook of hydraulic fluid technology

    CERN Document Server

    Totten, George E

    2011-01-01

    ""The Handbook of Hydraulic Fluid Technology"" serves as the foremost resource for designing hydraulic systems and for selecting hydraulic fluids used in engineering applications. Featuring new illustrations, data tables, as well as practical examples, this second edition is updated with essential information on the latest hydraulic fluids and testing methods. The detailed text facilitates unparalleled understanding of the total hydraulic system, including important hardware, fluid properties, and hydraulic lubricants. Written by worldwide experts, the book also offers a rigorous overview of h

  4. Research of performance prediction to energy on hydraulic turbine

    International Nuclear Information System (INIS)

    Quan, H; Li, R N; Li, Q F; Han, W; Su, Q M

    2012-01-01

    Refer to the low specific speed Francis turbine blade design principle and double-suction pump structure. Then, design a horizontal double-channel hydraulic turbine Francis. Through adding different guide vane airfoil and and no guide vane airfoil on the hydraulic conductivity components to predict hydraulic turbine energy and using Fluent software to numerical simulation that the operating conditions and point. The results show that the blade pressure surface and suction surface pressure is low when the hydraulic turbine installation is added standard positive curvature of the guide vane and modified positive curvature of guide vane. Therefore, the efficiency of energy recovery is low. However, the pressure of negative curvature guide vane and symmetric guide vane added on hydraulic turbine installations is larger than that of the former ones, and it is conducive to working of runner. With the decreasing of guide vane opening, increasing of inlet angle, flow state gets significantly worse. Then, others obvious phenomena are that the reflux and horizontal flow appeared in blade pressure surface. At the same time, the vortex was formed in Leaf Road, leading to the loss of energy. Through analyzing the distribution of pressure, velocity, flow lines of over-current flow in the the back hydraulic conductivity components in above programs we can known that the hydraulic turbine installation added guide vane is more reasonable than without guide vanes, it is conducive to improve efficiency of energy conversion.

  5. Characterisation of hydraulically-active fractures in a fractured ...

    African Journals Online (AJOL)

    2015-01-07

    Jan 7, 2015 ... injection and recovery tests were conducted for verification of the ... Keywords: self-potential method, hydraulically-conductive fractures, constant pressure injection and recovery ...... porous media 1: theory of the zeta potential.

  6. Compressed air piping, 241-SY-101 hydraulic pump retrieval trailer

    International Nuclear Information System (INIS)

    Wilson, T.R.

    1994-01-01

    The following Design Analysis was prepared by the Westinghouse Hanford Company to determine pressure losses in the compressed air piping installed on the hydraulic trailer for the 241-SY-101 pump retrieval mission

  7. Analysis of hydraulic bearing effect for vertical-shaft pump

    International Nuclear Information System (INIS)

    Narabayashi, Tadashi; Mawatari, Katsuhiko; Uchida, Ken; Iikura, Takahiko; Hayakawa, Kiyoshi

    1999-01-01

    In inner-rotating non coaxial cylinders, axial flow causes a hydraulic being effect by which the inner cylinder is put at the center of the axis of the outer cylinder, because of the pressure distribution along the surface of the inner cylinder. When the rotating speed becomes higher, whirl force is generated by the pressure distribution in the narrow gap side. Therefore, pocket-type hydraulic being was added between the rotor and the wearing, based on an experiment and flow analysis. The pockets suck a part of discharged water of a pump and pressurize a water along the rotational direction in the pocket. The pressurized water enhance the hydraulic being effect. The analysis results showed good agreement with the experiments, and the analysis method for the hydraulic being for vertical-shaft pump was established. (author)

  8. Proceedings of the 8. Brazilian Meeting on Reactor Physics and Thermal Hydraulics

    International Nuclear Information System (INIS)

    1991-01-01

    Some papers about pressurized light water reactors, fast reactors, accident analysis, transients, research reactors, nuclear data collection, thermal hydraulics, reactor monitoring, neutronics are presented. (E.G.)

  9. TMI-2 in-vessel hydraulic systems utilize high water and high boron content fluids

    International Nuclear Information System (INIS)

    Baston, V.F.; Hofstetter, K.J.; Hofman, L.A.; Gallagher, R.E.

    1987-01-01

    Choice of a hydraulic fluid for use in the Three Mile Island Unit 2 (TMI-2) reactor vessel defueling equipment required consideration of the following constraints for the hydraulic fluid given an accidental spill into the reactor coolant system (RCS). The TMI-2 RCS hydraulic fluid utilized in the hydraulic operations utilized a solution composition of 95 wt% water and 5 wt% of the above base fluid. The TMI-2 hydraulic system utilizes pressures up to 3500 psi. The selected hydraulic fluid has been in use since December 1986 with minimal operational difficulties

  10. Hydraulic efficiency of a Rushton turbine impeller

    Science.gov (United States)

    Chara, Z.; Kysela, B.; Fort, I.

    2017-07-01

    Based on CFD simulations hydraulic efficiency of a standard Rushton turbine impeller in a baffled tank was determined at a Reynolds number of ReM=33330. Instantaneous values of pressure and velocity components were used to draw up the macroscopic balance of the mechanical energy. It was shown that the hydraulic efficiency of the Rushton turbine impeller (energy dissipated in a bulk volume) is about 57%. Using this result we estimated a length scale in a non-dimensional equation of kinetic energy dissipation rate in the bulk volume as L=D/2.62.

  11. Non-stationary flow of hydraulic oil in long pipe

    Directory of Open Access Journals (Sweden)

    Hružík Lumír

    2014-03-01

    Full Text Available The paper deals with experimental evaluation and numerical simulation of non-stationary flow of hydraulic oil in a long hydraulic line. Non-stationary flow is caused by a quick closing of valves at the beginning and the end of the pipe. Time dependence of pressure is measured by means of pressure sensors at the beginning and the end of the pipe. A mathematical model of a given circuit is created using Matlab SimHydraulics software. The long line is simulated by means of segmented pipe. The simulation is verified by experiment.

  12. Greater-confinement disposal

    International Nuclear Information System (INIS)

    Trevorrow, L.E.; Schubert, J.P.

    1989-01-01

    Greater-confinement disposal (GCD) is a general term for low-level waste (LLW) disposal technologies that employ natural and/or engineered barriers and provide a degree of confinement greater than that of shallow-land burial (SLB) but possibly less than that of a geologic repository. Thus GCD is associated with lower risk/hazard ratios than SLB. Although any number of disposal technologies might satisfy the definition of GCD, eight have been selected for consideration in this discussion. These technologies include: (1) earth-covered tumuli, (2) concrete structures, both above and below grade, (3) deep trenches, (4) augered shafts, (5) rock cavities, (6) abandoned mines, (7) high-integrity containers, and (8) hydrofracture. Each of these technologies employ several operations that are mature,however, some are at more advanced stages of development and demonstration than others. Each is defined and further described by information on design, advantages and disadvantages, special equipment requirements, and characteristic operations such as construction, waste emplacement, and closure

  13. Highly reliable electro-hydraulic control system

    International Nuclear Information System (INIS)

    Mande, Morima; Hiyama, Hiroshi; Takahashi, Makoto

    1984-01-01

    The unscheduled shutdown of nuclear power stations disturbs power system, and exerts large influence on power generation cost due to the lowering of capacity ratio; therefore, high reliability is required for the control system of nuclear power stations. Toshiba Corp. has exerted effort to improve the reliability of the control system of power stations, and in this report, the electro-hydraulic control system for the turbines of nuclear power stations is described. The main functions of the electro-hydraulic control system are the control of main steam pressure with steam regulation valves and turbine bypass valves, the control of turbine speed and load, the prevention of turbine overspeed, the protection of turbines and so on. The system is composed of pressure sensors and a speed sensor, the control board containing the electronic circuits for control computation and protective sequence, the oil cylinders, servo valves and opening detectors of the valves for control, a high pressure oil hydraulic machine and piping, the operating panel and so on. The main features are the adoption of tripling intermediate value selection method, the multiplying of protection sensors and the adoption of 2 out of 3 trip logic, the multiplying of power sources, the improvement of the reliability of electronic circuit hardware and oil hydraulic system. (Kako, I.)

  14. Hydraulic Yaw System

    DEFF Research Database (Denmark)

    Stubkier, Søren; Pedersen, Henrik C.; Mørkholt, M.

    a hydraulic soft yaw system, which is able to reduce the loads on the wind turbine significantly. A full scale hydraulic yaw test rig is available for experiments and tests. The test rig is presented as well as the system schematics of the hydraulic yaw system....... the HAWC2 aeroelastic code and an extended model of the NREL 5MW turbine combined with a simplified linear model of the turbine, the parameters of the soft yaw system are optimized to reduce loading in critical components. Results shows that a significant reduction in fatigue and extreme loads to the yaw...... system and rotor shaft when utilizing the soft yaw drive concept compared to the original stiff yaw system. The physical demands of the hydraulic yaw system are furthermore examined for a life time of 20 years. Based on the extrapolated loads, the duty cycles show that it is possible to construct...

  15. Water Hydraulic Systems

    DEFF Research Database (Denmark)

    Conrad, Finn

    2005-01-01

    The paper presents research results using IT-Tools for CAD and dynamic modelling, simulation, analysis, and design of water hydraulic actuators for motion control of machines, lifts, cranes and robots. Matlab/Simulink and CATIA are used as IT-Tools. The contributions include results from on......-going research projects on fluid power and mechatronics based on tap water hydraulic servovalves and linear servo actuators and rotary vane actuators for motion control and power transmission. Development and design a novel water hydraulic rotary vane actuator for robot manipulators. Proposed mathematical...... modelling, control and simulation of a water hydraulic rotary vane actuator applied to power and control a two-links manipulator and evaluate performance. The results include engineering design and test of the proposed simulation models compared with IHA Tampere University’s presentation of research...

  16. Hydraulic hoisting and backfilling

    Science.gov (United States)

    Sauermann, H. B.

    In a country such as South Africa, with its large deep level mining industry, improvements in mining and hoisting techniques could result in substantial savings. Hoisting techniques, for example, may be improved by the introduction of hydraulic hoisting. The following are some of the advantages of hydraulic hoisting as against conventional skip hoisting: (1) smaller shafts are required because the pipes to hoist the same quantity of ore hydraulically require less space in the shaft than does skip hoisting equipment; (2) the hoisting capacity of a mine can easily be increased without the necessity of sinking new shafts. Large savings in capital costs can thus be made; (3) fully automatic control is possible with hydraulic hoisting and therefore less manpower is required; and (4) health and safety conditions will be improved.

  17. Ground source energy in crystalline bedrock - increased energy extraction by using hydraulic fracturing in boreholes

    Energy Technology Data Exchange (ETDEWEB)

    Ramstad, Randi Kalstad

    2004-11-01

    The use of improved equipment and methodology can result in considerable reductions in the drilling costs for medium- to large sized ground source heat pump system in crystalline bedrock. The main point has been to use special techniques within hydraulic fracturing to create a larger heat exchange area in the bedrock, and thus a greater energy extraction per borehole. The energy extraction is based on circulating groundwater. Stimulation with hydraulic fracturing is a well known technique in order to improve borehole yields for drinking water-, oil-, and geothermal purposes. A procedure for injection of propping agents in selected borehole sections, and custom-made equipment for hydraulic fracturing in crystalline bedrock, a double packer, have been developed in this study. The propping agents are likely to ensure a permanent improvement of the hydraulic conductivity in a long-run perspective. In addition to a pre-test, a comprehensive test programme has been performed at each of the two pilot plants at Bryn and at the former property of Energiselskapet Asker og Baerum (EAB) in Baerum municipality outside Oslo, Norway. A total of 125 stimulations with hydraulic fracturing using water-only and hydraulic fracturing with injection of sand have been performed in 9 boreholes. Test pumping and geophysical logging (temperature, electrical conductivity, gamma radiation, optical televiewer and flow measurements) have been carried out in order to document the effect of the hydraulic fracturing. The pilot plants at Bryn and EAB, where the ground source heat pump systems are based on circulating groundwater, have demonstrated the short-period energy extraction, limitations and opportunities of the concept for hydraulic fracturing and increased energy extraction in different geological and hydrogeological areas. The bedrock at Bryn and EAB is characterized as a low-metamorphic sandstone and a nodular limestone, respectively. At Bryn, the five boreholes were organised with a

  18. The Influence of Hydraulic Fracturing on Carbon Storage Performance

    Science.gov (United States)

    Fu, Pengcheng; Settgast, Randolph R.; Hao, Yue; Morris, Joseph P.; Ryerson, Frederick J.

    2017-12-01

    Conventional principles of the design and operation of geologic carbon storage (GCS) require injecting CO2 below the caprock fracturing pressure to ensure the integrity of the storage complex. In nonideal storage reservoirs with relatively low permeability, pressure buildup can lead to hydraulic fracturing of the reservoir and caprock. While the GCS community has generally viewed hydraulic fractures as a key risk to storage integrity, a carefully designed stimulation treatment under appropriate geologic conditions could provide improved injectivity while maintaining overall seal integrity. A vertically contained hydraulic fracture, either in the reservoir rock or extending a limited height into the caprock, provides an effective means to access reservoir volume far from the injection well. Employing a fully coupled numerical model of hydraulic fracturing, solid deformation, and matrix fluid flow, we study the enabling conditions, processes, and mechanisms of hydraulic fracturing during CO2 injection. A hydraulic fracture's pressure-limiting behavior dictates that the near-well fluid pressure is only slightly higher than the fracturing pressure of the rock and is insensitive to injection rate and mechanical properties of the formation. Although a fracture contained solely within the reservoir rock with no caprock penetration, would be an ideal scenario, poroelastic principles dictate that sustaining such a fracture could lead to continuously increasing pressure until the caprock fractures. We also investigate the propagation pattern and injection pressure responses of a hydraulic fracture propagating in a caprock subjected to heterogeneous in situ stress. The results have important implications for the use of hydraulic fracturing as a tool for managing storage performance.

  19. More features, greater connectivity.

    Science.gov (United States)

    Hunt, Sarah

    2015-09-01

    Changes in our political infrastructure, the continuing frailties of our economy, and a stark growth in population, have greatly impacted upon the perceived stability of the NHS. Healthcare teams have had to adapt to these changes, and so too have the technologies upon which they rely to deliver first-class patient care. Here Sarah Hunt, marketing co-ordinator at Aid Call, assesses how the changing healthcare environment has affected one of its fundamental technologies - the nurse call system, argues the case for wireless such systems in terms of what the company claims is greater adaptability to changing needs, and considers the ever-wider range of features and functions available from today's nurse call equipment, particularly via connectivity with both mobile devices, and ancillaries ranging from enuresis sensors to staff attack alert 'badges'.

  20. Greater oil investment opportunities

    International Nuclear Information System (INIS)

    Arenas, Ismael Enrique

    1997-01-01

    Geologically speaking, Colombia is a very attractive country for the world oil community. According to this philosophy new and important steps are being taken to reinforce the oil sector: Expansion of the exploratory frontier by including a larger number of sedimentary areas, and the adoption of innovative contracting instruments. Colombia has to offer, Greater economic incentives for the exploration of new areas to expand the exploratory frontier, stimulation of exploration in areas with prospectivity for small fields. Companies may offer Ecopetrol a participation in production over and above royalties, without it's participating in the investments and costs of these fields, more favorable conditions for natural gas seeking projects, in comparison with those governing the terms for oil

  1. The hydraulic wheel

    International Nuclear Information System (INIS)

    Alvarez Cardona, A.

    1985-01-01

    The present article this dedicated to recover a technology that key in disuse for the appearance of other techniques. It is the hydraulic wheel with their multiple possibilities to use their energy mechanical rotational in direct form or to generate electricity directly in the fields in the place and to avoid the high cost of transport and transformation. The basic theory is described that consists in: the power of the currents of water and the hydraulic receivers. The power of the currents is determined knowing the flow and east knowing the section of the flow and its speed; they are given you formulate to know these and direct mensuration methods by means of floodgates, drains and jumps of water. The hydraulic receivers or properly this hydraulic wheels that are the machines in those that the water acts like main force and they are designed to transmit the biggest proportion possible of absolute work of the water, the hydraulic wheels of horizontal axis are the common and they are divided in: you rotate with water for under, you rotate with side water and wheels with water for above. It is analyzed each one of them, their components are described; the conditions that should complete to produce a certain power and formulate them to calculate it. There are 25 descriptive figures of the different hydraulic wheels

  2. Hydraulic resistance of biofilms

    KAUST Repository

    Dreszer, C.

    2013-02-01

    Biofilms may interfere with membrane performance in at least three ways: (i) increase of the transmembrane pressure drop, (ii) increase of feed channel (feed-concentrate) pressure drop, and (iii) increase of transmembrane passage. Given the relevance of biofouling, it is surprising how few data exist about the hydraulic resistance of biofilms that may affect the transmembrane pressure drop and membrane passage. In this study, biofilms were generated in a lab scale cross flow microfiltration system at two fluxes (20 and 100Lm-2h-1) and constant cross flow (0.1ms-1). As a nutrient source, acetate was added (1.0mgL-1 acetate C) besides a control without nutrient supply. A microfiltration (MF) membrane was chosen because the MF membrane resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric substances (EPS) were determined, it was demonstrated that no internal membrane fouling occurred and that the fouling layer actually consisted of a grown biofilm and was not a filter cake of accumulated bacterial cells. At 20Lm-2h-1 flux with a nutrient dosage of 1mgL-1 acetate C, the resistance after 4 days reached a value of 6×1012m-1. At 100Lm-2h-1 flux under the same conditions, the resistance was 5×1013m-1. No correlation of biofilm resistance to biofilm thickness was found; Biofilms with similar thickness could have different resistance depending on the applied flux. The cell number in biofilms was between 4×107 and 5×108 cellscm-2. At this number, bacterial cells make up less than a half percent of the overall biofilm volume and therefore did not hamper the water flow through the biofilm significantly. A flux of 100Lm-2h-1 with nutrient supply caused higher cell numbers, more biomass, and higher biofilm resistance than a flux of 20Lm-2h-1. However, the biofilm thickness

  3. Experimental study of thermal–hydraulic performance of cam-shaped tube bundle with staggered arrangement

    International Nuclear Information System (INIS)

    Bayat, Hamidreza; Lavasani, Arash Mirabdolah; Maarefdoost, Taher

    2014-01-01

    Highlights: • Thermal–hydraulic performance of a non-circular tube bundle has been investigated experimentally. • Tubes were mounted in staggered arrangement with two longitudinal pitch ratios 1.5 and 2. • Drag coefficient and Nusselt number of tubes in second row was measured. • Friction factor of this tube bundle is lower than circular tube bundle. • Thermal–hydraulic performance of this tube bundle is greater than circular tube bundle. - Abstract: Flow and heat transfer from cam-shaped tube bank in staggered arrangement is studied experimentally. Tubes were located in test section of an open loop wind tunnel with two longitudinal pitch ratios 1.5 and 2. Reynolds number varies in range of 27,000 ⩽ Re D ⩽ 42,500 and tubes surface temperature is between 78 and 85 °C. Results show that both drag coefficient and Nusselt number depends on position of tube in tube bank and Reynolds number. Tubes in the first column have maximum value of drag coefficient, while its Nusselt number is minimum compared to other tubes in tube bank. Moreover, pressure drop from this tube bank is about 92–93% lower than circular tube bank and as a result thermal–hydraulic performance of this tube bank is about 6 times greater than circular tube bank

  4. Dynamic Analysis & Characterization of Conventional Hydraulic Power Supply Units

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Liedhegener, Michael; Bech, Michael Møller

    2016-01-01

    Hydraulic power units operated as constant supply pres-sure systems remain to be widely used in the industry, to supply valve controlled hydraulic drives etc., where the hydraulic power units are constituted by variable pumps with mechanical outlet pressure control, driven by induction motors....... In the analysis of supplied drives, both linear and rotary, emphasis is commonly placed on the drives themselves and the related loads, and the supply system dynamics is often given only little attention, and usually neglected or taken into account in a simplified fashion. The simplified supply system dynamics...... and drives will reduce the flow-to-pressure gain of the supply system, and hence increase the time constant of the sup-ply pressure dynamics. A consequence of this may be large vari-ations in the supply pressure, hence large variations in the pump shaft torque, and thereby the induction motor load torque...

  5. Fundamental test results of a hydraulic free piston internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Hibi, A.; Ito, T. [Toyohashi University of Technology (Japan). Dept. of Mechanical Engineering

    2004-10-01

    The hydraulic free piston internal combustion engine pump that has been constructed and tested in this work is the opposed piston, two-stroke cycle, uniflow scavenging, direct fuel injection, and compression ignition type. The opposed engine pistons reciprocate the hydraulic pump pistons directly and the hydraulic power to be used in the hydraulic motors is generated. The hydraulic pressure generated is substantially constant. The opposed free pistons rest after every gas cycle and hydraulic power is continuously supplied by a hydraulic accumulator during the free pistons' rest. The smaller the hydraulic flow output, the longer the duration of the rest. Every gas cycle is performed under a fixed working condition independent of hydraulic power output. The test results in this work indicate that the number of gas cycles per second of the free piston engine pump is directly proportional to hydraulic flow output. The opposed free pistons operate every 53.2 s when hydraulic flow output is 1.02 cm{sup 3}/s; at that time hydraulic power output is 0.0124 kW. Hydraulic thermal efficiency, the ratio of hydraulic energy produced to fuel energy consumed, has been measured in the range 0.0124 kW to 4.88 kW of hydraulic power output and it has become clear that hydraulic thermal efficiency in this range is constant. The measured value of hydraulic thermal efficiency is 31 per cent. It has been demonstrated that hydraulic thermal efficiency is kept constant even if hydraulic power output is very small. (author)

  6. Elevator and hydraulics; Elevator to yuatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, I. [Hitachi, Ltd., Tokyo (Japan)

    1994-07-15

    A hydraulic type elevator is installed in relatively lower buildings as compared with a rope type elevator, but the ratio in the number of installation of the former elevator is increasing. This paper explains from its construction and features to especially various control systems for the riding comfort and safety. A direct push-up system with hydraulic jacks arranged beneath a car, and an indirect push-up system that has hydraulic jacks arranged on flank of a car and transmits the movement of a plunger via a rope are available. The latter system eliminates the need of large holes to embed hydraulic jacks. While the speed is controlled by controlling flow rates of high-pressure oil, the speed, position, acceleration and even time differential calculus of the acceleration must be controlled severely. The system uses two-step control for the through-speed and the landing speed. Different systems that have been realized may include compensation for temperatures in flow rate control valves, load pressures, and oil viscosity, from learning control to fuzzy control for psychological effects, or control of inverters in motors. 13 refs., 12 figs., 1 tab.

  7. Method to Estimate the Dissolved Air Content in Hydraulic Fluid

    Science.gov (United States)

    Hauser, Daniel M.

    2011-01-01

    In order to verify the air content in hydraulic fluid, an instrument was needed to measure the dissolved air content before the fluid was loaded into the system. The instrument also needed to measure the dissolved air content in situ and in real time during the de-aeration process. The current methods used to measure the dissolved air content require the fluid to be drawn from the hydraulic system, and additional offline laboratory processing time is involved. During laboratory processing, there is a potential for contamination to occur, especially when subsaturated fluid is to be analyzed. A new method measures the amount of dissolved air in hydraulic fluid through the use of a dissolved oxygen meter. The device measures the dissolved air content through an in situ, real-time process that requires no additional offline laboratory processing time. The method utilizes an instrument that measures the partial pressure of oxygen in the hydraulic fluid. By using a standardized calculation procedure that relates the oxygen partial pressure to the volume of dissolved air in solution, the dissolved air content is estimated. The technique employs luminescent quenching technology to determine the partial pressure of oxygen in the hydraulic fluid. An estimated Henry s law coefficient for oxygen and nitrogen in hydraulic fluid is calculated using a standard method to estimate the solubility of gases in lubricants. The amount of dissolved oxygen in the hydraulic fluid is estimated using the Henry s solubility coefficient and the measured partial pressure of oxygen in solution. The amount of dissolved nitrogen that is in solution is estimated by assuming that the ratio of dissolved nitrogen to dissolved oxygen is equal to the ratio of the gas solubility of nitrogen to oxygen at atmospheric pressure and temperature. The technique was performed at atmospheric pressure and room temperature. The technique could be theoretically carried out at higher pressures and elevated

  8. Hydraulics and pneumatics

    CERN Document Server

    Parr, Andrew

    2006-01-01

    Nearly all industrial processes require objects to be moved, manipulated or subjected to some sort of force. This is frequently accomplished by means of electrical equipment (such as motors or solenoids), or via devices driven by air (pneumatics) or liquids (hydraulics).This book has been written by a process control engineer as a guide to the operation of hydraulic and pneumatic systems for all engineers and technicians who wish to have an insight into the components and operation of such a system.This second edition has been fully updated to include all recent developments su

  9. HYDRAULIC SERVO CONTROL MECHANISM

    Science.gov (United States)

    Hussey, R.B.; Gottsche, M.J. Jr.

    1963-09-17

    A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

  10. Hydraulic Arm Modeling via Matlab SimHydraulics

    Czech Academy of Sciences Publication Activity Database

    Věchet, Stanislav; Krejsa, Jiří

    2009-01-01

    Roč. 16, č. 4 (2009), s. 287-296 ISSN 1802-1484 Institutional research plan: CEZ:AV0Z20760514 Keywords : simulatin modeling * hydraulics * SimHydraulics Subject RIV: JD - Computer Applications, Robotics

  11. Trends in Design of Water Hydraulics

    DEFF Research Database (Denmark)

    Conrad, Finn

    2005-01-01

    ordinary tap water and the range of application areas are illustrated with examples, in particular within the food processing industry, humidification operations, water mist systems for fire fighting, high water pressure cleaners, water moisturising systems for wood processing, lumber drying process...... operate with pure water from the tap without additives of any kind. Hence water hydraulics takes the benefit of pure water as fluid being environmentally friendly, easy to clean sanitary design, non-toxic, non-flammable, inexpensive, readily available and easily disposable. The low-pressure tap water...... and accessories running with sea-water as fluid are available. A unique solution is to use reverse osmosis to generate drinking water from sea-water, and furthermore for several off-shore applications. Furthermore, tap water hydraulic components of the Nessie® family and examples of measured performance...

  12. Mine drivage in hydraulic mines

    Energy Technology Data Exchange (ETDEWEB)

    Ehkber, B Ya

    1983-09-01

    From 20 to 25% of labor cost in hydraulic coal mines falls on mine drivage. Range of mine drivage is high due to the large number of shortwalls mined by hydraulic monitors. Reducing mining cost in hydraulic mines depends on lowering drivage cost by use of new drivage systems or by increasing efficiency of drivage systems used at present. The following drivage methods used in hydraulic mines are compared: heading machines with hydraulic haulage of cut rocks and coal, hydraulic monitors with hydraulic haulage, drilling and blasting with hydraulic haulage of blasted rocks. Mining and geologic conditions which influence selection of the optimum mine drivage system are analyzed. Standardized cross sections of mine roadways driven by the 3 methods are shown in schemes. Support systems used in mine roadways are compared: timber supports, roof bolts, roof bolts with steel elements, and roadways driven in rocks without a support system. Heading machines (K-56MG, GPKG, 4PU, PK-3M) and hydraulic monitors (GMDTs-3M, 12GD-2) used for mine drivage are described. Data on mine drivage in hydraulic coal mines in the Kuzbass are discussed. From 40 to 46% of roadways are driven by heading machines with hydraulic haulage and from 12 to 15% by hydraulic monitors with hydraulic haulage.

  13. Liquid metal thermal-hydraulics

    International Nuclear Information System (INIS)

    Kottowski-Duemenil, H.M.

    1994-01-01

    This textbook is a report of the 26 years activity of the Liquid Metal Boiling Working Group (LMBWG). It summarizes the state of the art of liquid metal thermo-hydraulics achieved through the collaboration of scientists concerned with the development of the Fast Breeder Reactor. The first chapter entitled ''Liquid Metal Boiling Behaviour'', presents the background and boiling mechanisms. This section gives the reader a brief but thorough survey on the superheat phenomena in liquid metals. The second chapter of the text, ''A Review of Single and Two-Phase Flow Pressure Drop Studies and Application to Flow Stability Analysis of Boiling Liquid Metal Systems'' summarizes the difficulty of pressure drop simulation of boiling sodium in core bundles. The third chapter ''Liquid Metal Dry-Out Data for Flow in Tubes and Bundles'' describes the conditions of critical heat flux which limits the coolability of the reactor core. The fourth chapter dealing with the LMFBR specific topic of ''Natural Convection Cooling of Liquid Metal Systems''. This chapter gives a review of both plant experiments and out-of-pile experiments and shows the advances in the development of computing power over the past decade of mathematical modelling ''Subassembly Blockages Suties'' are discussed in chapter five. Chapter six is entitled ''A Review of the Methods and Codes Available for the Calculation on Thermal-Hydraulics in Rod-Cluster and other Geometries, Steady state and Transient Boiling Flow Regimes, and the Validation achieves''. Codes available for the calculation of thermal-hydraulics in rod-clusters and other geometries are reviewed. Chapter seven, ''Comparative Studies of Thermohydraulic Computer Code Simulations of Sodium Boiling under Loss of Flow Conditions'', represents one of the key activities of the LMBWG. Several benchmark exercises were performed with the aim of transient sodium boiling simulation in single channels and bundle blockages under steady state conditions and loss of

  14. Hydraulic upright of a mine support

    Energy Technology Data Exchange (ETDEWEB)

    Solomakhin, A N; Il' in, V A; Ponomarenko, Yu F; Shakhmeyster, Yu L

    1979-04-30

    The hydraulic upright of a mine support, which includes a housing, piston with compacting element and dirt collector, rod and guide sleeve, is described. In order to improve protection of the piston element from abrasive particles and to reduce the pressure differential the piston of the upright is also equipped with a compaction ring, whose lateral surface has a groove beneath the compacting element. The surface on the side of the working fluid supply is made conical in order to remove dirt.

  15. Design of a Hydraulic Motor System Driven by Compressed Air

    Directory of Open Access Journals (Sweden)

    Jyun-Jhe Yu

    2013-06-01

    Full Text Available This paper presents the design of a highly efficient pneumatic motor system. The air engine is currently the most generally used device to convert potential energy of compressed air into mechanical energy. However, the efficiency of the air engines is too low to provide sufficient operating range for the vehicle. In this study, the energy contained in compressed air/pressurized hydraulic oil is transformed by a hydraulic motor to mechanical energy to enhance the efficiency of using air power. To evaluate the theoretical efficiency, the principle of balance of energy is applied. The theoretical efficiency of converting air into hydraulic energy is found to be a function of pressure; thus, the maximum converting efficiency can be determined. To confirm the theoretical evaluation, a prototype of the pneumatic hydraulic system is built. The experiment verifies that the theoretical evaluation of the system efficiency is reasonable, and that the layout of the system is determined by the results of theoretical evaluation.

  16. Hydraulic shock absorbers

    International Nuclear Information System (INIS)

    Thatcher, G.; Davidson, D. F.

    1984-01-01

    A hydraulic shock absorber of the dash pot kind for use with electrically conducting liquid such as sodium, has magnet means for electro magnetically braking a stream of liquid discharged from the cylinder. The shock absorber finds use in a liquid metal cooled nuclear reactor for arresting control rods

  17. Preparation of hydraulic cement

    Energy Technology Data Exchange (ETDEWEB)

    1921-08-28

    A process for the preparation of hydraulic cement by the use of oil-shale residues is characterized in that the oil-shale refuse is mixed with granular basic blast-furnace slag and a small amount of portland cement and ground together.

  18. Small hydraulic turbine drives

    Science.gov (United States)

    Rostafinski, W. A.

    1970-01-01

    Turbine, driven by the fluid being pumped, requires no external controls, is completely integrated into the flow system, and has bearings which utilize the main fluid for lubrication and cooling. Torque capabilities compare favorably with those developed by positive displacement hydraulic motors.

  19. Modelling of Hydraulic Robot

    DEFF Research Database (Denmark)

    Madsen, Henrik; Zhou, Jianjun; Hansen, Lars Henrik

    1997-01-01

    This paper describes a case study of identifying the physical model (or the grey box model) of a hydraulic test robot. The obtained model is intended to provide a basis for model-based control of the robot. The physical model is formulated in continuous time and is derived by application...

  20. Manual Hydraulic Structures

    NARCIS (Netherlands)

    Molenaar, W.F.; Voorendt, M.Z.

    This manual is the result of group work and origins in Dutch lecture notes that have been used since long time. Amongst the employees of the Hydraulic Engineering Department that contributed to this work are dr.ir. S. van Baars, ir.K.G.Bezuijen, ir.G.P.Bourguignon, prof.ir.A.Glerum,

  1. Water Treatment Technology - Hydraulics.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on hydraulics provides instructional materials for three competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: head loss in pipes in series, function loss in…

  2. Technology and control for hydraulic manipulators

    International Nuclear Information System (INIS)

    Measson, Y.; David, O.; Louveau, F.; Friconneau, J.P.

    2003-01-01

    Hydraulic manipulators are candidate for fusion reactor maintenance. Their main advantages are their large payload with respect to volume and mass, their reliability and their robustness. However, due to their force control limitations, they are disqualified for precise manipulation and are dangerous for the environment and themselves in case of unexpected collision. CEA, in collaboration with CYBERNETIX and IFREMER has developed the advanced hydraulic robot MAESTRO. Force and hybrid control has been developed in order to avoid the previous problems. Using 'pressure' control servo-valve instead of the standard 'flow' control servo-valve (standard configuration of the MAESTRO) makes a real simplification of the control loop. No more pressure sensors are needed for monitoring the hydraulic joint in force control mode and using this kind of valves makes big safety improvements. The French company IN-LHC, designed and manufactured a prototype of servo-valve that fits the performances and space constraints of the Maestro arm. A characterisation of this new product was made on a mock-up and a set of these prototypes integrated in the Maestro slave-arm. A comparison between the two actuating technologies was made and showed that the performances of the pressure servo-valves make it applicable to general application

  3. Cradle modification for hydraulic ram

    International Nuclear Information System (INIS)

    Koons, B.M.

    1995-01-01

    The analysis of the cradle hydraulic system considers stress, weld strength, and hydraulic forces required to lift and support the cradle/pump assembly. The stress and weld strength of the cradle modifications is evaluated to ensure that they meet the requirements of the American Institute for Steel Construction (AISC 1989). The hydraulic forces are evaluated to ensure that the hydraulic system is capable of rotating the cradle and pump assembly to the vertical position (between 70 degrees and 90 degrees)

  4. Design of a Hydraulic Motor System Driven by Compressed Air

    OpenAIRE

    Shaw, Dein; Yu, Jyun-Jhe; Chieh, Cheng

    2013-01-01

    This paper presents the design of a highly efficient pneumatic motor system. The air engine is currently the most generally used device to convert potential energy of compressed air into mechanical energy. However, the efficiency of the air engines is too low to provide sufficient operating range for the vehicle. In this study, the energy contained in compressed air/pressurized hydraulic oil is transformed by a hydraulic motor to mechanical energy to enhance the efficiency of using air power....

  5. Thermal-hydraulic characteristic of the PGV-1000 steam generator

    International Nuclear Information System (INIS)

    Ubra, O.; Doubek, M.

    1995-01-01

    Horizontal steam generators are typical parts of nuclear power plants with pressure water reactor type VVER. By means of this computer program, a detailed thermal-hydraulic study of the horizontal steam generator PGV-1000 has been carried out and a special attention has been paid to the thermal-hydraulics of the secondary side. A set of important steam generator characteristics has been obtained and analyzed. Some of the interesting results of the analysis are presented in the paper. (author)

  6. Quasi-open loop hydraulic ram incremental actuator with power conserving properties

    International Nuclear Information System (INIS)

    Raymond, E.T.; Robinson, C.W.

    1982-01-01

    An electric stepping motor, operated by command signals from a computer or a microprocessor, rotates a rotary control member of a distributor valve, for sequencing hydraulic pressure and hence flow to the cylinders of an axial piston hydraulic machine. A group of the cylinders are subjected to pressure and flow and the remaining cylinders are vented to a return line. Rotation of the rotary control valve member sequences pressurization by progressively adding a cylinder to the forward edge to the pressurized group and removing a cylinder from the trailing edge of the pressurized group. The double ended pistons of each new pressurized group function to drive a wobble plate into a new position of equilibrium and then hold it in such position until another change in the makeup of the pressurized group. These pistons also displace hydraulic fluid from the opposite cylinder head which serves as the output of a pumping element. An increment of displacement of the wobble plate occurs in direct response to each command pulse that is received by the stepping motor. Wobble plate displacement drives the rotary valve of the hydraulic power transfer unit, causing it to transfer hydraulic fluid from a first expansible chamber on one side of a piston in a hydraulic ram to a second expansible chamber on the opposite side of the piston. Reverse drive of the hydraulic power transfer unit reverses the direction of transfer of hydraulic fluid between the two expansible chambers

  7. Hydraulic conductivity of compacted clay frozen and thawed in situ

    International Nuclear Information System (INIS)

    Benson, C.H.; Othman, M.A.

    1993-01-01

    A large specimen of compacted clay (diameter = 298 mm; thickness = 914 mm) was subjected to freeze-thaw in the field for 60 days. Afterward, the hydraulic conductivity was measured. The hydraulic conductivity of the entire specimen remained essentially unchanged, but increases in hydraulic conductivity of 1.5-2 orders of magnitude were observed above the freezing plane. The increase in hydraulic conductivity was highest at the top of the specimen and decreased with depth. Changes in hydraulic conductivity also occurred at depths 150 mm below the freezing plane, where desiccation occurred because of water redistribution. Numerous horizontal and vertical cracks formed in the soil mass. Dissection of the sample after permeation revealed that the cracks were laden with water. Cracking was greatest at the surface and became less frequent with depth. For depths greater than 150 mm below the freezing plane, cracking was absent. The frequency of cracks is consistent with principles of mechanistic models of soil freezing. The results of laboratory tests were used to predict the hydraulic conductivity of the large specimen. Tests were conducted on specimens subjected to various freeze-thaw cycles, temperature gradients, and states of stress. It was found that the predicted hydraulic conductivities were lower than those measured on the large specimen, but they closely resembled the trend in hydraulic conductivity with depth

  8. Hydraulic turbines and auxiliary equipment

    Energy Technology Data Exchange (ETDEWEB)

    Luo Gaorong [Organization of the United Nations, Beijing (China). International Centre of Small Hydroelectric Power Plants

    1995-07-01

    This document presents a general overview on hydraulic turbines and auxiliary equipment, emphasizing the turbine classification, in accordance with the different types of turbines, standard turbine series in China, turbine selection based on the basic data required for the preliminary design, general hill model curves, chart of turbine series and the arrangement of application for hydraulic turbines, hydraulic turbine testing, and speed regulating device.

  9. Hydraulic Hybrid Vehicle Publications | Transportation Research | NREL

    Science.gov (United States)

    Hydraulic Hybrid Vehicle Publications Hydraulic Hybrid Vehicle Publications The following technical papers and fact sheets provide information about NREL's hydraulic hybrid fleet vehicle evaluations . Refuse Trucks Project Startup: Evaluating the Performance of Hydraulic Hybrid Refuse Vehicles. Bob

  10. Hydraulic characteristics of HANARO fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S.; Chung, H. J.; Chun, S. Y.; Yang, S. K.; Chung, M. K. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    This paper presents the hydraulic characteristics measured by using LDV (Laser Doppler Velocimetry) in subchannels of HANARO, KAERI research reactor, fuel bundle. The fuel bundle consists of 18 axially finned rods with 3 spacer grids, which are arranged in cylindrical configuration. The effects of the spacer grids on the turbulent flow were investigated by the experimental results. Pressure drops for each component of the fuel bundle were measured, and the friction factors of fuel bundle and loss coefficients for the spacer grids were estimated from the measured pressure drops. Implications regarding the turbulent thermal mixing were discussed. Vibration test results measured by using laser vibrometer were presented. 9 refs., 12 figs. (Author)

  11. Hydraulic characteristics of HANARO fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S; Chung, H J; Chun, S Y; Yang, S K; Chung, M K [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    This paper presents the hydraulic characteristics measured by using LDV (Laser Doppler Velocimetry) in subchannels of HANARO, KAERI research reactor, fuel bundle. The fuel bundle consists of 18 axially finned rods with 3 spacer grids, which are arranged in cylindrical configuration. The effects of the spacer grids on the turbulent flow were investigated by the experimental results. Pressure drops for each component of the fuel bundle were measured, and the friction factors of fuel bundle and loss coefficients for the spacer grids were estimated from the measured pressure drops. Implications regarding the turbulent thermal mixing were discussed. Vibration test results measured by using laser vibrometer were presented. 9 refs., 12 figs. (Author)

  12. Subchannel flow analysis in Candu and ACR pressure tubes with radial and axial diameter variation

    Energy Technology Data Exchange (ETDEWEB)

    Catana, A.; Prodea, L. [RAAN, Institute for Nuclear Research, Arges (Romania); Danila, N.; Prisecaru, I.; Dupleac, D. [Bucharest Univ. Politehnica(Romania)

    2007-07-01

    The Candu (Canada Deuterium Uranium) and ACR (Advanced Candu Reactor) are pressure tubes (PT) heavy water moderated reactors. Candu are heavy water and ACR are light water cooled reactors. The pressure tube is filled with 12 bundles, each consisting of 37 respectively 43 fuel rods. One Candu reactor is in operation at Cernavoda, Romania since 1996. ACR is a proposed advanced Candu. PT diameter variation has a significant impact on the thermal-hydraulic parameters. Almost all thermal-hydraulic parameters change, but some of them have a greater significance. In this work we have considered a set of radial and axial PT diameter variations both for Candu-600 and ACR-700 reactors using various types of fuel bundles. We can conclude the following: 1) some thermal-hydraulic parameters are significantly influenced: critical heat flux (CHF), pressure drop, or void fraction; 2) the most significant parameter CHF is worsening which reduces the safety margin; 3) some fuel types present a better thermal-hydraulic behavior; and 4) fuel bundles with fresh fuel or low burnup have a worse thermal-hydraulic behaviour than those at average burn-up.

  13. Subchannel flow analysis in Candu and ACR pressure tubes with radial and axial diameter variation

    International Nuclear Information System (INIS)

    Catana, A.; Prodea, L.; Danila, N.; Prisecaru, I.; Dupleac, D.

    2007-01-01

    The Candu (Canada Deuterium Uranium) and ACR (Advanced Candu Reactor) are pressure tubes (PT) heavy water moderated reactors. Candu are heavy water and ACR are light water cooled reactors. The pressure tube is filled with 12 bundles, each consisting of 37 respectively 43 fuel rods. One Candu reactor is in operation at Cernavoda, Romania since 1996. ACR is a proposed advanced Candu. PT diameter variation has a significant impact on the thermal-hydraulic parameters. Almost all thermal-hydraulic parameters change, but some of them have a greater significance. In this work we have considered a set of radial and axial PT diameter variations both for Candu-600 and ACR-700 reactors using various types of fuel bundles. We can conclude the following: 1) some thermal-hydraulic parameters are significantly influenced: critical heat flux (CHF), pressure drop, or void fraction; 2) the most significant parameter CHF is worsening which reduces the safety margin; 3) some fuel types present a better thermal-hydraulic behavior; and 4) fuel bundles with fresh fuel or low burnup have a worse thermal-hydraulic behaviour than those at average burn-up

  14. Assimilation of temperature and hydraulic gradients for quantifying the spatial variability of streambed hydraulics

    Science.gov (United States)

    Huang, Xiang; Andrews, Charles B.; Liu, Jie; Yao, Yingying; Liu, Chuankun; Tyler, Scott W.; Selker, John S.; Zheng, Chunmiao

    2016-08-01

    Understanding the spatial and temporal characteristics of water flux into or out of shallow aquifers is imperative for water resources management and eco-environmental conservation. In this study, the spatial variability in the vertical specific fluxes and hydraulic conductivities in a streambed were evaluated by integrating distributed temperature sensing (DTS) data and vertical hydraulic gradients into an ensemble Kalman filter (EnKF) and smoother (EnKS) and an empirical thermal-mixing model. The formulation of the EnKF/EnKS assimilation scheme is based on a discretized 1D advection-conduction equation of heat transfer in the streambed. We first systematically tested a synthetic case and performed quantitative and statistical analyses to evaluate the performance of the assimilation schemes. Then a real-world case was evaluated to calculate assimilated specific flux. An initial estimate of the spatial distributions of the vertical hydraulic gradients was obtained from an empirical thermal-mixing model under steady-state conditions using a constant vertical hydraulic conductivity. Then, this initial estimate was updated by repeatedly dividing the assimilated specific flux by estimates of the vertical hydraulic gradients to obtain a refined spatial distribution of vertical hydraulic gradients and vertical hydraulic conductivities. Our results indicate that optimal parameters can be derived with fewer iterations but greater simulation effort using the EnKS compared with the EnKF. For the field application in a stream segment of the Heihe River Basin in northwest China, the average vertical hydraulic conductivities in the streambed varied over three orders of magnitude (5 × 10-1 to 5 × 102 m/d). The specific fluxes ranged from near zero (qz < ±0.05 m/d) to ±1.0 m/d, while the vertical hydraulic gradients were within the range of -0.2 to 0.15 m/m. The highest and most variable fluxes occurred adjacent to a debris-dam and bridge pier. This phenomenon is very likely

  15. Determining the Conditions for the Hydraulic Impacts Emergence at Hydraulic Systems

    Directory of Open Access Journals (Sweden)

    Mazurenko A.S.

    2017-08-01

    Full Text Available This research aim is to develop a method for modeling the conditions for the critical hydrau-lic impacts emergence on thermal and nuclear power plants’ pipeline systems pressure pumps depart-ing from the general provisions of the heat and hydrodynamic instability theory. On the developed method basis, the conditions giving rise to the reliability-critical hydraulic impacts emergence on pumps for the thermal and nuclear power plants’ typical pipeline system have been determined. With the flow characteristic minimum allowable (critical sensitivity, the flow velocity fluctuations ampli-tude reaches critical values at which the pumps working elements’ failure occurs. The critical hydrau-lic impacts emergence corresponds to the transition of the vibrational heat-hydrodynamic instability into an aperiodic one. As research revealed, a highly promising approach as to the preventing the criti-cal hydraulic impacts related to the foreground use of pumps having the most sensitive consumption (at supply network performance (while other technical characteristics corresponding to that parame-ter. The research novelty refers to the suggested method elaborated by the authors’ team, which, in contrast to traditional approaches, is efficient in determining the pump hydraulic impact occurrence conditions when the vibrational heat-hydrodynamic instability transition to the aperiodic instability.

  16. Experimental Investigation of Crack Extension Patterns in Hydraulic Fracturing with Shale, Sandstone and Granite Cores

    Directory of Open Access Journals (Sweden)

    Jianming He

    2016-12-01

    Full Text Available Hydraulic fracturing is an important method of reservoir stimulation in the exploitation of geothermal resources, and conventional and unconventional oil and gas resources. In this article, hydraulic fracturing experiments with shale, sandstone cores (from southern Sichuan Basin, and granite cores (from Inner Mongolia were conducted to investigate the different hydraulic fracture extension patterns in these three reservoir rocks. The different reactions between reservoir lithology and pump pressure can be reflected by the pump pressure monitoring curves of hydraulic fracture experiments. An X-ray computer tomography (CT scanner was employed to obtain the spatial distribution of hydraulic fractures in fractured shale, sandstone, and granite cores. From the microscopic and macroscopic observation of hydraulic fractures, different extension patterns of the hydraulic fracture can be analyzed. In fractured sandstone, symmetrical hydraulic fracture morphology could be formed, while some micro cracks were also induced near the injection hole. Although the macroscopic cracks in fractured granite cores are barely observed by naked eye, the results of X-ray CT scanning obviously show the morphology of hydraulic fractures. It is indicated that the typical bedding planes well developed in shale formation play an important role in the propagation of hydraulic fractures in shale cores. The results also demonstrated that heterogeneity influenced the pathway of the hydraulic fracture in granite cores.

  17. Hydraulically actuated artificial muscles

    Science.gov (United States)

    Meller, M. A.; Tiwari, R.; Wajcs, K. B.; Moses, C.; Reveles, I.; Garcia, E.

    2012-04-01

    Hydraulic Artificial Muscles (HAMs) consisting of a polymer tube constrained by a nylon mesh are presented in this paper. Despite the actuation mechanism being similar to its popular counterpart, which are pneumatically actuated (PAM), HAMs have not been studied in depth. HAMs offer the advantage of compliance, large force to weight ratio, low maintenance, and low cost over traditional hydraulic cylinders. Muscle characterization for isometric and isobaric tests are discussed and compared to PAMs. A model incorporating the effect of mesh angle and friction have also been developed. In addition, differential swelling of the muscle on actuation has also been included in the model. An application of lab fabricated HAMs for a meso-scale robotic system is also presented.

  18. Influence factors of sand-bentonite mixtures on hydraulic conductivity

    International Nuclear Information System (INIS)

    Chen Yonggui; Ye Weimin; Chen Bao; Wan Min; Wang Qiong

    2008-01-01

    Buffer material is a very important part of the engineering barrier for geological disposal of high-level radioactive nuclear waste. Compacted bentonite is attracting greater attention as buffer and backfill material because it offer impermeability and swelling properties, but the pure compacted bentonite strength decreases with increasing hydration and these will reduce the buffer capability. To solve this problem, sand is often used to form compacted sand-bentonite mixtures (SBMs) providing high thermal conductivity, excellent compaction capacity, long-time stability, and low engineering cost. As to SBMs, hydraulic conductivity is a important index for evaluation barrier capability. Based on the review of research results, the factors affecting the hydraulic conductivity of SBMs were put forward including bentonite content, grain size distribution, moisture content, dry density, compacting method and energy, and bentonite type. The studies show that the hydraulic conductivity of SBMs is controlled by the hydraulic conductivity of the bentonite, it also decreases as dry density and bentonite content increase, but when the bentonite content reach a critical point, the influence of increasing bentonite to decrease the hydraulic conductivity is limited. A fine and well-graded SBMs is likely to have a lower hydraulic conductivity than a coarse and poorly graded material. The internal erosion or erodibility based on the grain size distribution of the SBMs has a negative effect on the final hydraulic conductivity. The lowest hydraulic conductivity is gained when the mixtures are compacted close to optimum moisture content. Also, the mixtures compacted at moisture contents slightly above optimum values give lower hydraulic conductivity than when compacted at slightly under the optimum moisture content. Finally, discussion was brought to importance of compaction method, compacting energy, and bentonite type to the hydraulic conductivity of SBMs. (authors)

  19. Hydraulic nuts (HydraNuts) for reactor vessel tensioning

    International Nuclear Information System (INIS)

    Greenwell, Steve

    2008-01-01

    The paper will present how the introduction of hydraulic nuts - HydraNuts, has reduced critical path times, dose exposure for workers and improved working safety conditions around the reactor vessel during tensioning or de-tensioning operations. It will focus upon detailing the advantages realized by utilities that have introduced the technology and providing examples of the improvements made to the process as well as discussing the engineering design change packages required to make the conversion to the new system. HydraNuts replace the traditional mechanical nut/stud tensioning equipment, combining the two functions into a single system, designed for easy installation and operation by one individual. The primary components of the HydraNut can be assembled without the need for external crane or hoist support and are designed so that each sub assembly can be fitted separately. Once all HydraNuts are fitted to the Rx vessel studs and are sitting on the main Rx vessel head flange, then a system of flexible hydraulic hoses is connected to them, forming a closed loop hydraulic harness, which will allow for simultaneous pressurization of all HydraNuts. Hydraulic pressure is obtained by the use of a hydraulic pumping unit and the resultant load generated in each HydraNut is transferred to the stud and main flange closure is obtained. While maintaining hydraulic pressure, a locking ring is rotated into place on the HydraNut assembly that will support the tensioned load mechanically when the hydraulic pressure is released from the hose harness assembly. The hose harness is removed and the HydraNut is now functioning as a mechanical nut retaining the tensioned load. The HydraNut system for Rx vessel applications was first introduced into a plant in the U.S. in October 2006 and based upon the benefits realized subsequent projects are under way within the Asian and U.S. operating fleet. (author)

  20. TG 220 MW hydraulic control system diagnostics

    International Nuclear Information System (INIS)

    Svabcik, A.

    1996-01-01

    The TG power output control system comprises a hydraulic and an electronic part. TG speed, power output or the main steam header pressure (HPK) depend on the steam flow at the turbine inlet. The steam admission into the turbine is controlled by four control valves and one by-pass valve in case of the HP part and by four capture flap valves in case of the LP part. The task of the SKODA K-220 MW turbine protection and control systems is to provide both the turbine speed and power output control to the setpoint value. Diagnostic measurements were aimed at getting an overview of both technical and functional states of all power output control elements. Principally, it can be stated that some deficiencies of a design nature originating from the manufacturer's factory were revealed and some other deficiencies related to hydraulic control elements functionality were identified more closely by the new method. 5 figs

  1. TG 220 MW hydraulic control system diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Svabcik, A [Atomova Elektraren Bohunice, Jaslovske Bohunice (Slovakia)

    1997-12-31

    The TG power output control system comprises a hydraulic and an electronic part. TG speed, power output or the main steam header pressure (HPK) depend on the steam flow at the turbine inlet. The steam admission into the turbine is controlled by four control valves and one by-pass valve in case of the HP part and by four capture flap valves in case of the LP part. The task of the SKODA K-220 MW turbine protection and control systems is to provide both the turbine speed and power output control to the setpoint value. Diagnostic measurements were aimed at getting an overview of both technical and functional states of all power output control elements. Principally, it can be stated that some deficiencies of a design nature originating from the manufacturer`s factory were revealed and some other deficiencies related to hydraulic control elements functionality were identified more closely by the new method. 5 figs.

  2. Thermal Hydraulic Design of PWT Accelerating Structures

    CERN Document Server

    Yu, David; Chen Ping; Lundquist, Martin; Luo, Yan

    2005-01-01

    Microwave power losses on the surfaces of accelerating structures will transform to heat which will deform the structures if it is not removed in time. Thermal hydraulic design of the disk and cooling rods of a Plane Wave Transformer (PWT) structure is presented. Experiments to measure the hydraulic (pressure vs flow rate) and cooling (heat removed vs flow rate) properties of the PWT disk are performed, and results compared with simulations using Mathcad models and the COSMOSM code. Both experimental and simulation results showed that the heat deposited on the structure could be removed effectively using specially designed water-cooling circuits and the temperature of the structure could be controlled within the range required.

  3. Hydraulic System Design of Hydraulic Actuators for Large Butterfly Valves

    Directory of Open Access Journals (Sweden)

    Ye HUANG

    2014-09-01

    Full Text Available Hydraulic control systems of butterfly valves are presently valve-controlled and pump-controlled. Valve-controlled hydraulic systems have serious power loss and generate much heat during throttling. Pump-controlled hydraulic systems have no overflow or throttling losses but are limited in the speed adjustment of the variable-displacement pump, generate much noise, pollute the environment, and have motor power that does not match load requirements, resulting in low efficiency under light loads and wearing of the variable-displacement pump. To overcome these shortcomings, this article designs a closed hydraulic control system in which an AC servo motor drives a quantitative pump that controls a spiral swinging hydraulic cylinder, and analyzes and calculates the structure and parameters of a spiral swinging hydraulic cylinder. The hydraulic system adjusts the servo motor’s speed according to the requirements of the control system, and the motor power matches the power provided to components, thus eliminating the throttling loss of hydraulic circuits. The system is compact, produces a large output force, provides stable transmission, has a quick response, and is suitable as a hydraulic control system of a large butterfly valve.

  4. Hydraulic Soft Yaw System for Multi MW Wind Turbines

    DEFF Research Database (Denmark)

    Stubkier, Søren

    energy and an increase in the loading of the wind turbine structure and components. This dissertation examines the hypothesis that there are advantages of basing a yaw system on hydraulic components instead of normal electrical components. This is done through a state of the art analysis followed...... in the wind turbine yaw system along with minor reductions in the blades and main shaft. Optimization of the damping and stiffness of the hydraulic soft yaw system have been conducted and an optimum found for load reduction. Linear control algorithms for control of damping pressure peaks have been developed...... the full turbine code in FAST, and the mathematical model of the hydraulic yaw system in Matlab/Simulink and Amesim is developed in order to analyze a full scale model of the hydraulic yaw system in combination with the implemented friction model for the yaw system. These results are also promising...

  5. Leak-thight seals got high pressure testing of pipes, tanks, valves

    International Nuclear Information System (INIS)

    Estrade, J.

    1985-01-01

    Leak-tight seals ensure quick, safe and efficient testing of pipes with plain-ended or flanged openings, valves with flanged or welded edges, manifields, recipients, etc. They are inserted into the pipe end manually then simply a slight turn of the seal treated wheel commences the pressure test. Hydraulic pressure is supplied by a pump through the inlet seal and air is purged through the outlet seal which then closes. The higher the pressure, the greater the sealing strength of the seal which prevents accidental unplugging. There are different types of seals: for interior plain-ended openings, for pipes with plain-ended opening, for flanged pipes. (author)

  6. Operation of a T63 Turbine Engine Using F24 Contaminated Skydrol 5 Hydraulic Fluid

    Science.gov (United States)

    2016-09-01

    hydraulic fluids were originally developed by the Douglas Aircraft Company during the 1940s to reduce fire risk from leaking high pressure mineral oil...thermal load demands in modern hydraulic systems and reduced density to lower weight impact on the aircraft. Eastman Chemical is the current producer of...AFRL-RQ-WP-TM-2016-0155 OPERATION OF A T63 TURBINE ENGINE USING F24 CONTAMINATED SKYDROL 5 HYDRAULIC FLUID Matthew J. Wagner (AFRL/RQTM) James

  7. Influence of irrigation and fertilization on transpiration and hydraulic properties of Populus deltoides.

    Energy Technology Data Exchange (ETDEWEB)

    Samuelson, Lisa, J.; Stokes, Thomas, A.; Coleman, Mark, D.

    2007-02-01

    Summary Long-term hydraulic acclimation to resource availability was explored in 3-year-bld Populus deltoides Bartr. ex Marsh. clones by examining transpiration. leaf-specific hydraulic conductance (GL), canopy stomatal conductance (Gs) and leaf to sapwood area ratio (AL:Asi)n response to imgation (13 and 551 mm year in addition to ambient precipitation) and fertilization (0 and 120 kg N ha-' year-'). Sap flow was measured continuously over one growing season with thermal dissipation probes. Fertilization had a greater effect on growth and hydraulic properties than imgation, and fertilization effects were independent of irrigation treatment. Transpiration on a ground area basis (E) ranged between 0.3 and 1.8 mm day-', and increased 66% and 90% in response to imgation and fertilization, respectively. Increases in GL, Gs at a reference vapor pressure deficit of 1 kPa, and transpiration per unit leaf areain response to increases in resource availability were associated with reductions in AL:As and consequently a minimal change in the water potential gradient from soil to leaf. Imgation and fertilization increased leaf area index similarly, from an average 1.16 in control stands to 1.45, but sapwood area was increased from 4.0 to 6.3 m ha-' by irrigation and from 3.7 to 6.7 m2 ha-' by fertilization. The balance between leaf area and sapwood area was important in understanding long-term hydraulic acclimation to resource availability and mechanisms controlling maximum productivity in Populus deltoides.

  8. Hydraulic Apparatus for Mechanical Testing of Nuts

    Science.gov (United States)

    Hinkel, Todd J.; Dean, Richard J.; Hacker, Scott C.; Harrington, Douglas W.; Salazar, Frank

    2004-01-01

    The figure depicts an apparatus for mechanical testing of nuts. In the original application for which the apparatus was developed, the nuts are of a frangible type designed for use with pyrotechnic devices in spacecraft applications in which there are requirements for rapid, one-time separations of structures that are bolted together. The apparatus can also be used to test nonfrangible nuts engaged without pyrotechnic devices. This apparatus was developed to replace prior testing systems that were extremely heavy and immobile and characterized by long setup times (of the order of an hour for each nut to be tested). This apparatus is mobile, and the setup for each test can now be completed in about five minutes. The apparatus can load a nut under test with a static axial force of as much as 6.8 x 10(exp 5) lb (3.0 MN) and a static moment of as much as 8.5 x 10(exp 4) lb in. (9.6 x 10(exp 3) N(raised dot)m) for a predetermined amount of time. In the case of a test of a frangible nut, the pyrotechnic devices can be exploded to break the nut while the load is applied, in which case the breakage of the nut relieves the load. The apparatus can be operated remotely for safety during an explosive test. The load-generating portion of the apparatus is driven by low-pressure compressed air; the remainder of the apparatus is driven by 110-Vac electricity. From its source, the compressed air is fed to the apparatus through a regulator and a manually operated valve. The regulated compressed air is fed to a pneumatically driven hydraulic pump, which pressurizes oil in a hydraulic cylinder, thereby causing a load to be applied via a hydraulic nut (not to be confused with the nut under test). During operation, the hydraulic pressure is correlated with the applied axial load, which is verified by use of a load cell. Prior to operation, one end of a test stud (which could be an ordinary threaded rod or bolt) is installed in the hydraulic nut. The other end of the test stud passes

  9. Hydraulic Stability of Accropode Armour

    DEFF Research Database (Denmark)

    Jensen, T.; Burcharth, H. F.; Frigaard, Peter

    The present report describes the hydraulic model tests of Accropode armour layers carried out at the Hydraulics Laboratory at Aalborg University from November 1995 through March 1996. The objective of the model tests was to investigate the hydraulic stability of Accropode armour layers...... with permeable core (crushed granite with a gradation of 5-8 mm). The outcome of this study is described in "Hydraulic Stability of Single-Layer Dolos and Accropode Armour Layers" by Christensen & Burcharth (1995). In January/February 1996, Research Assistant Thomas Jensen carried out a similar study...

  10. Slope instability caused by small variations in hydraulic conductivity

    Science.gov (United States)

    Reid, M.E.

    1997-01-01

    Variations in hydraulic conductivity can greatly modify hillslope ground-water flow fields, effective-stress fields, and slope stability. In materials with uniform texture, hydraulic conductivities can vary over one to two orders of magnitude, yet small variations can be difficult to determine. The destabilizing effects caused by small (one order of magnitude or less) hydraulic conductivity variations using ground-water flow modeling, finite-element deformation analysis, and limit-equilibrium analysis are examined here. Low hydraulic conductivity materials that impede downslope ground-water flow can create unstable areas with locally elevated pore-water pressures. The destabilizing effects of small hydraulic heterogeneities can be as great as those induced by typical variations in the frictional strength (approximately 4??-8??) of texturally similar materials. Common "worst-case" assumptions about ground-water flow, such as a completely saturated "hydrostatic" pore-pressure distribution, do not account for locally elevated pore-water pressures and may not provide a conservative slope stability analysis. In site characterization, special attention should be paid to any materials that might impede downslope ground-water flow and create unstable regions.

  11. Modeling, Optimization & Control of Hydraulic Networks

    DEFF Research Database (Denmark)

    Tahavori, Maryamsadat

    2014-01-01

    . The nonlinear network model is derived based on the circuit theory. A suitable projection is used to reduce the state vector and to express the model in standard state-space form. Then, the controllability of nonlinear nonaffine hydraulic networks is studied. The Lie algebra-based controllability matrix is used......Water supply systems consist of a number of pumping stations, which deliver water to the customers via pipeline networks and elevated reservoirs. A huge amount of drinking water is lost before it reaches to end-users due to the leakage in pipe networks. A cost effective solution to reduce leakage...... in water network is pressure management. By reducing the pressure in the water network, the leakage can be reduced significantly. Also it reduces the amount of energy consumption in water networks. The primary purpose of this work is to develop control algorithms for pressure control in water supply...

  12. Hydraulic fracturing proppants

    Directory of Open Access Journals (Sweden)

    V. P. P. de Campos

    Full Text Available Abstract Hydrocarbon reservoirs can be classified as unconventional or conventional depending on the oil and gas extraction difficulty, such as the need for high-cost technology and techniques. The hydrocarbon extraction from bituminous shale, commonly known as shale gas/oil, is performed by using the hydraulic fracturing technique in unconventional reservoirs where 95% water, 0.5% of additives and 4.5% of proppants are used. Environmental problems related to hydraulic fracturing technique and better performance/development of proppants are the current challenge faced by companies, researchers, regulatory agencies, environmentalists, governments and society. Shale gas is expected to increase USA fuel production, which triggers the development of new proppants and technologies of exploration. This paper presents a review of the definition of proppants, their types, characteristics and situation in the world market and information about manufacturers. The production of nanoscale materials such as anticorrosive and intelligent proppants besides proppants with carbon nanotubes is already carried out on a scale of tonnes per year in Belgium, Germany and Asia countries.

  13. Hydraulic jett mixing

    International Nuclear Information System (INIS)

    Ackerman, J.R.

    1989-01-01

    Efficient mixing of reactants into a waste stream has always been a problem in that there has been no mixer capable of combining all the elements of enhanced mixing into a single piece of equipment. Through the development of a mixing system for the mining industry to treat acid mine water containing heavy metals, a versatile new hydraulic jetting static mixer has been developed that has no moving parts and a clean bore with no internal components. This paper reports that the main goal of the development of the hydraulic jett mixer was to reduce the size of the tankage required for an acid mine drainage (AMD) treatment plant through development of a static mixing device that could coincidentally aerate the treatment flow. This process equipment being developed would simultaneously adjust the pH and oxidize the metals allowing formation of the hydroxide sludges required for sedimentation and removal of the metals from the treatment stream. In effect, the device eliminates two reaction tanks, the neutralization/mixing tank and the aeration tank

  14. Applied hydraulic transients

    CERN Document Server

    Chaudhry, M Hanif

    2014-01-01

    This book covers hydraulic transients in a comprehensive and systematic manner from introduction to advanced level and presents various methods of analysis for computer solution. The field of application of the book is very broad and diverse and covers areas such as hydroelectric projects, pumped storage schemes, water-supply systems, cooling-water systems, oil pipelines and industrial piping systems. Strong emphasis is given to practical applications, including several case studies, problems of applied nature, and design criteria. This will help design engineers and introduce students to real-life projects. This book also: ·         Presents modern methods of analysis suitable for computer analysis, such as the method of characteristics, explicit and implicit finite-difference methods and matrix methods ·         Includes case studies of actual projects ·         Provides extensive and complete treatment of governed hydraulic turbines ·         Presents design charts, desi...

  15. The Thermal Hydraulics of Tube Support Fouling in Nuclear Steam Generators

    International Nuclear Information System (INIS)

    Rummens, Helena E.C.; Rogers, J.T.; Turner, C.W.

    2004-01-01

    It is hypothesized that the thermal-hydraulic environment plays a role in the fouling of tube supports in nuclear steam generators. Experiments were performed to simulate the thermal-hydraulic environment near various designs of supports. Pressure loss, local velocity, turbulence intensity, and local void fraction were measured to characterize the effect of the support. Fouling mechanisms specific to supports were inferred from these experimental data and from actual steam generator inspection results. An analytical model was developed to predict the rate of particulate deposition on the supports, to better understand the complex processes involved.This paper presents the following set of tools for assessing the fouling propensity of a given support design: (1) proposed fouling mechanisms, (2) criteria for support fouling propensity, (3) correlation of fouling with parameters such as mass flux and quality, (4) descriptions of experimental tools such as flow visualization and measurement of pressure-loss profiles, and (5) analytical tools.An important conclusion from this and our previous work is that the fouling propensity is greater with broached support plates, both trefoil and quatrefoil, than with lattice bar supports and formed bar supports, in which significant cross flows occur

  16. Cavitation instabilities in hydraulic machines

    International Nuclear Information System (INIS)

    Tsujimoto, Y

    2013-01-01

    Cavitation instabilities in hydraulic machines, hydro turbines and turbopump inducers, are reviewed focusing on the cause of instabilities. One-dimensional model of hydro turbine system shows that the overload surge is caused by the diffuser effect of the draft tube. Experiments show that this effect also causes the surge mode oscillations at part load. One dimensional model of a cavitating turbopump inducer shows that the mass flow gain factor, representing the cavity volume increase caused by the incidence angle increase is the cause of cavitation surge and rotating cavitation. Two dimensional model of a cavitating turbopump inducer shows that various modes of cavitation instabilities start to occur when the cavity length becomes about 65% of the blade spacing. This is caused by the interaction of the local flow near the cavity trailing edge with the leading edge of the next blade. It was shown by a 3D CFD that this is true also for real cases with tip cavitation. In all cases, it was shown that cavitation instabilities are caused by the fundamental characteristics of cavities that the cavity volume increases with the decrease of ambient pressure or the increase of the incidence angle

  17. Thermal hydraulic design of PFBR core

    International Nuclear Information System (INIS)

    Roychowdhury, D.G.; Vinayagam, P.P.; Ravichandar, S.C.

    2000-01-01

    The thermal-hydraulic design of core is important in respecting temperature limits while achieving higher outlet temperature. This paper deals with the analytical process developed and implemented for analysing steady state thermal-hydraulics of PFBR core. A computer code FLONE has been developed for optimisation of flow allocation through the subassemblies (SA). By calibrating β n (ratio between the maximum channel temperature rise and SA average temperature rise) values with SUPERENERGY code and using these values in FLONE code, prediction of average and maximum coolant temperature distribution is found to be reasonably accurate. Hence, FLONE code is very powerful design tool for core design. A computer code SAPD has been developed to calculate the pressure drop of fuel and blanket SA. Selection of spacer wire pitch depends on the pressure drop, flow-induced vibration and the mixing characteristics. A parametric study was made for optimisation of spacer wire pitch for the fuel SA. Experimental programme with 19 pin-bundle has been undertaken to find the flow-induced vibration characteristics of fuel SA. Also, experimental programme has been undertaken on a full-scale model to find the pressure drop characteristics in unorificed SA, orifices and the lifting force on the SA. (author)

  18. An Analytic Approach to Cascade Control Design for Hydraulic Valve-Cylinder Drives

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Hansen, Anders Hedegaard; Andersen, Torben O.

    2016-01-01

    , unfortunately not present in valve-operated hydraulic drives. This paper considers a cascade control approach for hydraulic valve-cylinder drives motivated by the fact that this may be applied to successfully suppress nonlinearities. The drive is pre-compensated utilizing a pressure updated inverse valve flow...

  19. Improving the support characteristics of hydraulic fill

    Energy Technology Data Exchange (ETDEWEB)

    Corson, D. R.; Dorman, K. R.; Sprute, R. H.

    1980-05-15

    Extensive laboratory and field testing has defined the physical properties of hydraulic fill. Effect of void ratio on percolation rate has been quantified, and tests were developed to estimate waterflow through fill material in a given state underground. Beneficial effect on fill's support capability through addition of cement alone or in conjunction with vibratory compaction has been investigated. Two separate field studies in operating cut-and-fill mines measured vein-wall deformation and loads imposed on backfilled stopes. Technology has been developed that will effectively and efficiently dewater and densify ultra-fine-grained slurries typical of metal mine hydraulic backfill. At least two operators are using this electrokinetic technique to dewater slimes collected in underground sumps or impoundments. This technique opens up the possibility of using the total unclassified tailings product as a hydraulic backfill. Theoretical enhancement of ground support and rock-burst control through improved support capability will be tested in a full-scale mine stope installation. Both a horizontal layer and a vertical column of high modulus fill will be placed in an attempt to reduce stope wall closure, support more ground pressure, and lessen rock-burst occurrence.

  20. Pressure fluctuations on the bed of surge tank at the H.P. Zimapan, Hgo., with different arrangements studied on hydraulic model, with the lowest operation conditions; Fluctuaciones de presion en la base del pozo de oscilacion del P.H. Zimapan Hgo., con diferentes arreglos estudiados en modelo hidraulico ante las condiciones minimas de operacion

    Energy Technology Data Exchange (ETDEWEB)

    Marengo Mogollon, H. [Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico (Mexico)]. E-mail: humberto.marengo@cfe.gob.mx; Ochoa Alvarez, F.J.; Cortes Cortes, C. [Comision Federal de Electricidad (Mexico)]. E-mail: federico.ochoa@cfe.gob.mx; carlos.cortes01@cfe.gob.mx

    2009-10-15

    In this paper, the pressure fluctuations of the surge tank in the Zimapan Hydroelectric Project are compared in a hydraulic model. The shaft is located lateral, over the conduction tunnel and in the simple form (permitting the tunnel entering the shaft); with and without orifice plates taking into account the demand and supply condition of energy with the minimum level of water of the conduction. It was determined the hydraulic efficiency and it was found that it was the best constructive option. [Spanish] En este articulo se comparan las fluctuaciones de presion en el pozo de oscilacion del P.H. Zimapan, Hgo., Mexico las cuales fueron estudiadas en modelo hidraulico al considerar dicho pozo ubicado en diferentes posiciones; lateralmente y sobre el eje de la conduccion; pozo simple y con tuberia de conexion; con y sin placa de orificio, para maniobras de rechazo y demanda de carga de las turbinas de generacion con el nivel del agua correspondiente al NAMINO. Se determino la eficiencia hidraulica comparandola con las otras opciones encontrandose que la mejor opcion para el funcionamiento hidraulico es el pozo lateral, que ademas permite optimizar el procedimiento constructivo.

  1. Process of preparing hydraulic cement

    Energy Technology Data Exchange (ETDEWEB)

    1919-12-11

    A process of preparing hydraulic cement from oil shale or shale coke is characterized in that the oil shale or shale coke after the distillation is burned long and hot to liberate the usual amount of carbonic acid and then is fine ground to obtain a slow hardening hydraulic cement.

  2. Equipment for hydraulic testing

    International Nuclear Information System (INIS)

    Jacobsson, L.; Norlander, H.

    1981-07-01

    Hydraulic testing in boreholes is one major task of the hydrogeological program in the Stripa Project. A new testing equipment for this purpose was constructed. It consists of a downhole part and a surface part. The downhole part consists of two packers enclosing two test-sections when inflated; one between the packers and one between the bottom packer and the bottom of the borehole. A probe for downhole electronics is also included in the downhole equipment together with electrical cable and nylon tubing. In order to perform shut-in and pulse tests with high accuracy a surface controlled downhole valve was constructed. The surface equipment consists of the data acquisition system, transducer amplifier and surface gauges. In the report detailed descriptions of each component in the whole testing equipment are given. (Auth.)

  3. Thermal-hydraulic tests for reactor safety system

    International Nuclear Information System (INIS)

    Chun, Se Young; Chung, Moon Ki; Baek, Won Pil

    2002-05-01

    Tests for the safety depressurization system, Sparger adopted for the Korean next generation reactor, APR1400 are carried out for several geometries with the B and C (Blowdown and Condensation) facility in the condition of high temperature and pressure and with a small test facility in the condition of atmospheric temperature and pressure. Tests for the critical heat flux are performed with the RCS(Reactor Coolant System) facility as well as with the Freon CHF Loop in the condition of high temperature and pressure. The atmospheric temperature and pressure facility is utilized for development of the high standard thermal hydraulic measurement technology. The optical method is developed to measure the local thermal-hydraulic behavior for the single and two-phase boiling phenomena

  4. Hydraulic oil control system for transformer stations

    International Nuclear Information System (INIS)

    Truong, P.

    2002-01-01

    'Full text:' Electrical oil control systems are commonly used to contain large volumes of spilled oil in transformer stations. Specially calibrated floats, some of which are designed to float only in oil and others only in water, are used in combination with a pump to contain oil at the catch basin below a transformer station.This electrical control system requires frequent maintenance and inspections to ensure the electrical system is not affected by any electrical surges. Also the floats need to be inspected and cleaned frequently to prevent oil or grit build up that may affect the systems' ability to contain oil.Recognizing the limitations of electrical oil control systems, Hydro One is investigating alternative control systems. A hydraulic oil control system is being investigated as an alternative which can backup oil in a containment area while allowing any water entering the containment area to pass through. Figure 1 shows a schematic of a bench-top model tested at Ryerson University. Oil and water separation occurs within the double-piped column. Oil and water are allowed to enter the external pipe column but only water is allowed to exit the internal pipe column. The internal pipe column is designed to generate enough hydrostatic pressure to ensure the oil is contained in the external pipe column.The hydraulic oil control system provides a reliable control mechanism and requires less maintenance compared to that of the electrical control system. Since the hydraulic oil control system has no moving parts, nor would any parts that require electricity, it is not affected by electrical surges such as lightening.The maintenance requirements of the hydraulic oil control system are: the removal of any oil and grit from the catch basin, and the occasional visual inspection for any crack or clogs in the system. (author)

  5. APPROBATION OF THE NUMERICAL METHOD OF CALCULATING THE DYNAMIC STRESS-STRAIN STATE OF THE THREE-DIMENSIONAL SYSTEM “FOUNDATION – FACILITY OF THE PRESSURE FRONT HYDRAULIC ENGINEERING STRUCTURE – WATER RESERVOIR” ON THE EXAMPLE OF THE CLUSTER-REGULATOR

    Directory of Open Access Journals (Sweden)

    Dmitry S. Dmitriev

    2018-03-01

    Full Text Available In the article, the results of approbation of the developed technique of the refined numerical simula-tion of the dynamic stress-strain state of the three-dimensional system “ground base (earth foundation – reser-voir – construction of the pressure head of the hydraulic system” under seismic influences. A comparison is made between two different ways of modeling the fluid interacting with the structure and the base of the hydroe-lectric power station. The issues of choosing the dimensions of the base unit and taking into account the inertial load from it, as well as the method of determining the initial seismic action, are touched upon.

  6. Trade-offs between xylem hydraulic properties, wood anatomy and yield in Populus.

    Science.gov (United States)

    Hajek, Peter; Leuschner, Christoph; Hertel, Dietrich; Delzon, Sylvain; Schuldt, Bernhard

    2014-07-01

    Trees face the dilemma that achieving high plant productivity is accompanied by a risk of drought-induced hydraulic failure due to a trade-off in the trees' vascular system between hydraulic efficiency and safety. By investigating the xylem anatomy of branches and coarse roots, and measuring branch axial hydraulic conductivity and vulnerability to cavitation in 4-year-old field-grown aspen plants of five demes (Populus tremula L. and Populus tremuloides Michx.) differing in growth rate, we tested the hypotheses that (i) demes differ in wood anatomical and hydraulic properties, (ii) hydraulic efficiency and safety are related to xylem anatomical traits, and (iii) aboveground productivity and hydraulic efficiency are negatively correlated to cavitation resistance. Significant deme differences existed in seven of the nine investigated branch-related anatomical and hydraulic traits but only in one of the four coarse-root-related anatomical traits; this likely is a consequence of high intra-plant variation in root morphology and the occurrence of a few 'high-conductivity roots'. Growth rate was positively related to branch hydraulic efficiency (xylem-specific conductivity) but not to cavitation resistance; this indicates that no marked trade-off exists between cavitation resistance and growth. Both branch hydraulic safety and hydraulic efficiency significantly depended on vessel size and were related to the genetic distance between the demes, while the xylem pressure causing 88% loss of hydraulic conductivity (P88 value) was more closely related to hydraulic efficiency than the commonly used P50 value. Deme-specific variation in the pit membrane structure may explain why vessel size was not directly linked to growth rate. We conclude that branch hydraulic efficiency is an important growth-influencing trait in aspen, while the assumed trade-off between productivity and hydraulic safety is weak. © The Author 2014. Published by Oxford University Press. All rights reserved

  7. Hydraulic resistance of biofilms

    KAUST Repository

    Dreszer, C.; Vrouwenvelder, Johannes S.; Paulitsch-Fuchs, Astrid H.; Zwijnenburg, Arie; Kruithof, Joop C.; Flemming, Hans Curt

    2013-01-01

    resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric

  8. Theoretical Modeling of Rock Breakage by Hydraulic and Mechanical Tool

    Directory of Open Access Journals (Sweden)

    Hongxiang Jiang

    2014-01-01

    Full Text Available Rock breakage by coupled mechanical and hydraulic action has been developed over the past several decades, but theoretical study on rock fragmentation by mechanical tool with water pressure assistance was still lacking. The theoretical model of rock breakage by mechanical tool was developed based on the rock fracture mechanics and the solution of Boussinesq’s problem, and it could explain the process of rock fragmentation as well as predicating the peak reacting force. The theoretical model of rock breakage by coupled mechanical and hydraulic action was developed according to the superposition principle of intensity factors at the crack tip, and the reacting force of mechanical tool assisted by hydraulic action could be reduced obviously if the crack with a critical length could be produced by mechanical or hydraulic impact. The experimental results indicated that the peak reacting force could be reduced about 15% assisted by medium water pressure, and quick reduction of reacting force after peak value decreased the specific energy consumption of rock fragmentation by mechanical tool. The crack formation by mechanical or hydraulic impact was the prerequisite to improvement of the ability of combined breakage.

  9. Hydraulic accumulator-compressor for geopressured enhanced oil recovery

    Science.gov (United States)

    Goldsberry, Fred L.

    1988-01-01

    A hydraulic accumulator-compressor vessel using geothermal brine under pressure as a piston to compress waste (CO.sub.2 rich) gas is used in a system having a plurality of gas separators in tandem to recover pipeline quality gas from geothermal brine. A first high pressure separator feeds gas to a membrance separator which separates low pressure waste gas from high pressure quality gas. A second separator produces low pressure waste gas. Waste gas from both separators is combined and fed into the vessel through a port at the top as the vessel is drained for another compression cycle. High pressure brine is then admitted into the vessel through a port at the bottom of the vessel. Check valves control the flow of low pressure waste gas into the vessel and high pressure waste gas out of the vessel.

  10. Xylem hydraulic safety margins in woody plants: coordination of stomatal control of xylem tension with hydraulic capacitance

    Science.gov (United States)

    Frederick C. Meinzer; Daniel M. Johnson; Barbara Lachenbruch; Katherine A. McCulloh; David R. Woodruff

    2009-01-01

    The xylem pressure inducing 50% loss of hydraulic conductivity due to embolism (P50) is widely used for comparisons of xylem vulnerability among species and across aridity gradients. However, despite its utility as an index of resistance to catastrophic xylem failure under extreme drought, P50 may have no special...

  11. Process and device for conditioning low and medium activity radioactive effluents with hydraulic binders

    International Nuclear Information System (INIS)

    Jaouen, C.; Magnin, G.; Renault, G.

    1986-01-01

    Chemical processing of borated radioactive effluents is claimed. Tetrahydrated calcium borate crystals are prepared by lime additions, the volume is reduced by evaporation under reduced pressure and the product obtained is mixed with hydraulic binders [fr

  12. Hydraulic tests for the Excavation Disturbed Zone in NATM drift of North Extension

    International Nuclear Information System (INIS)

    Matsuoka, Eiken

    1997-03-01

    Investigation for characterization of rock properties of the Excavation Disturbed Zone (EDZ) were carried out in NATM drift of North Extension in the Tono Mine. As a part of this investigation, hydraulic tests were performed by means of the hydraulic measuring instrument, which had been developed by PNC Tono Geoscience Center. The purpose of this tests is to characterize the change in hydraulic properties of the EDZ caused by drift excavation using machine (boom header). The hydraulic tests were performed in the burials MH-1,2,3, in which hydraulic tests had been performed before the drift excavation in 1994. The test results indicate that the measured values of pore water pressure have decreased after excavation of the drift. The values ranged from -0.037 kgf/cm 2 to 0.039 kgf/cm 2 . The measured hydraulic conductivities ranged from 2.2*10 -11 cm/s to 9.1*10 -11 cm/s for mud stone and from 2.8*10 -9 cm/s to 2.4*10 -7 cm/s for conglomerate. The measured hydraulic conductivities for mud stone are below the lower limit of the instrument, and the change in the hydraulic conductivities for conglomerate is little. The hydraulic conductivities for conglomerate and mad stone (reference values) are interpreted. The change in hydraulic conductivities measured before and after excavation of the drift is insignificant. (author)

  13. Design and Optimization of Fast Switching Valves for Large Scale Digital Hydraulic Motors

    DEFF Research Database (Denmark)

    Roemer, Daniel Beck

    The present thesis is on the design, analysis and optimization of fast switching valves for digital hydraulic motors with high power ratings. The need for such high power motors origins in the potential use of hydrostatic transmissions in wind turbine drive trains, as digital hydraulic machines...... have been shown to improve the overall efficiency and efficient operation range compared to traditional hydraulic machines. Digital hydraulic motors uses electronically controlled independent seat valves connected to the pressure chambers, which must be fast acting and exhibit low pressure losses...... to enable efficient operation. These valves are complex components to design, as multiple design aspects are present in these integrated valve units, with conflicting objectives and interdependencies. A preliminary study on a small scale single-cylinder digital hydraulic pump has initially been conducted...

  14. SBWR core thermal hydraulic analysis during startup

    International Nuclear Information System (INIS)

    Lin, J.H.; Huang, R.L.; Sawyer, C.D.

    1993-01-01

    This paper reports on a thermal hydraulic analysis of the SIMPLIFIED BOILING WATER REACTOR (SBWR) during startup. The potential instability during a SBWR startup has drawn the attention of designers, researchers, and engineers. It has not been a concern for a Boiling Water Reactor (BWR) with forced recirculation; however, for SBWR with natural circulation the concern exists. The concern is about the possibility of a geysering mode oscillation during SBWR startup from a cold temperature and a low system pressure with a low natural circulation flow rate. A thermal hydraulic analysis of the SBWR is performed in simulation of the startup using the TRACG computer code. The temperature, pressure, and reactor power profiles of SBWR during the startup are presented. The results are compared with the data of a natural circulation boiling water reactor, the DODEWAARD plant, in which no instabilities have been observed during many startups. It is shown that a SBWR startup which follows proper procedures, geysering and other modes of oscillations can be avoided

  15. Hydraulic testing of Salado Formation evaporites at the Waste Isolation Pilot Plant site: Second interpretive report

    Energy Technology Data Exchange (ETDEWEB)

    Beauheim, R.L. [Sandia National Labs., Albuquerque, NM (United States); Roberts, R.M.; Dale, T.F.; Fort, M.D.; Stensrud, W.A. [INTERA, Inc., Austin, TX (United States)

    1993-12-01

    Pressure-pulse, constant-pressure flow, and pressure-buildup tests have been performed in bedded evaporites of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site to evaluate the hydraulic properties controlling brine flow through the Salado. Transmissivities have been interpreted from six sequences of tests conducted on five stratigraphic intervals within 15 m of the WIPP underground excavations.

  16. Hydraulic testing of Salado Formation evaporites at the Waste Isolation Pilot Plant site: Second interpretive report

    International Nuclear Information System (INIS)

    Beauheim, R.L.; Roberts, R.M.; Dale, T.F.; Fort, M.D.; Stensrud, W.A.

    1993-12-01

    Pressure-pulse, constant-pressure flow, and pressure-buildup tests have been performed in bedded evaporites of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site to evaluate the hydraulic properties controlling brine flow through the Salado. Transmissivities have been interpreted from six sequences of tests conducted on five stratigraphic intervals within 15 m of the WIPP underground excavations

  17. Study of thermal - hydraulic sensors signal fluctuations in PWR

    International Nuclear Information System (INIS)

    Hennion, F.

    1987-10-01

    This thesis deals with signal fluctuations of thermal-hydraulic sensors in the main coolant primary of a pressurized water reactor. The aim of this work is to give a first response about the potentiality of use of these noise signals for the functionning monitoring. Two aspects have been studied: - the modelisation of temperature fluctuations of core thermocouples, by a Monte-Carlo method, gives the main characteristics of these signals and their domain of application. - the determination of eigenfrequency in the primary by an acoustic representation could permit the monitoring of local and global thermo-hydraulic conditions [fr

  18. Research on MEMS sensor in hydraulic system flow detection

    Science.gov (United States)

    Zhang, Hongpeng; Zhang, Yindong; Liu, Dong; Ji, Yulong; Jiang, Jihai; Sun, Yuqing

    2011-05-01

    With the development of mechatronics technology and fault diagnosis theory, people regard flow information much more than before. Cheap, fast and accurate flow sensors are urgently needed by hydraulic industry. So MEMS sensor, which is small, low cost, well performed and easy to integrate, will surely play an important role in this field. Based on the new method of flow measurement which was put forward by our research group, this paper completed the measurement of flow rate in hydraulic system by setting up the mathematical model, using numerical simulation method and doing physical experiment. Based on viscous fluid flow equations we deduced differential pressure-velocity model of this new sensor and did optimization on parameters. Then, we designed and manufactured the throttle and studied the velocity and pressure field inside the sensor by FLUENT. Also in simulation we get the differential pressure-velocity curve .The model machine was simulated too to direct experiment. In the static experiments we calibrated the MEMS sensing element and built some sample sensors. Then in a hydraulic testing system we compared the sensor signal with a turbine meter. It presented good linearity and could meet general hydraulic system use. Based on the CFD curves, we analyzed the error reasons and made some suggestion to improve. In the dynamic test, we confirmed this sensor can realize high frequency flow detection by a 7 piston-pump.

  19. Compatibility between Hydraulic and Mechanical Properties of Ceramic Water Filters

    Directory of Open Access Journals (Sweden)

    Riyadh Z. Al Zubaidy

    2017-05-01

    Full Text Available In this paper, ceramic water filters were produced by using ten mixtures of different ratios of red clay and sawdust under different production conditions. The physical properties of these filters were tested. The production conditions include five press pressures ranged from 10 to 50MPa and a firing schedule having three different final temperatures of 1000, 1070, and 1100˚C. The tests results of the physical properties were used to obtain best compatibility between the hydraulic and the mechanical properties of these filters. Results showed that as the press pressure and the firing temperature are increased, the bulk density and the compressive and bending strengths of the produced filters are increased, while, the porosity and absorption are decreased. As the sawdust content is increased the bulk density and the compressive and bending strengths are decreased, while, the porosity and absorption are increased. High hydraulic conductivity is obtained at a firing temperature of 1070˚C when the sawdust content is less than 10%. Otherwise, it is increased as sawdust content and the firing temperature are increased. Filters made of mixture 92.5% red clay and 7.5% sawdust formed . under a press pressure of 20MPa and a firing temperature of 1070˚C gave the best compatibility between hydraulic and mechanical properties. In this case, the hydraulic conductivity was 50mm/day, the compressive strength was 14MPa, and the bending strength was 10.8MPa.

  20. HYDRAULICS, SHELBY COUNTY, KENTUCKY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...

  1. HYDRAULICS, MEADE COUNTY, KENTUCKY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...

  2. Steam generator thermal-hydraulics

    International Nuclear Information System (INIS)

    Inch, W.W.; Scott, D.A.; Carver, M.B.

    1980-01-01

    This paper discusses a code for detailed numerical modelling of steam generator thermal-hydraulics, and describes related experimental programs designed to promote in-depth understanding of three-dimensional two-phase flow. (auth)

  3. Entupimento de gotejadores e seu efeito na pressão da rede hidráulica de um sistema de microirrigação Clogging of drippers and its effect on the hydraulic network pressure in a micro-irrigation system

    Directory of Open Access Journals (Sweden)

    Luís F. Faria

    2002-01-01

    Full Text Available Com o presente trabalho, objetivou-se avaliar a sobreelevação de pressão na rede hidráulica de um sistema de irrigação por gotejamento, quando ocorre redução da vazão por entupimento dos emissores. A área avaliada foi de 280 ha, irrigando citrus através de gotejamento subsuperficial, com emissores autocompensantes. A metodologia consistiu num modelo matemático baseado na equação de Bernoulli, utilizando-se uma planilha eletrônica para simular os efeitos do entupimento dos emissores na malha hidráulica. Para estimar a variação de pressão no sistema, simulou-se obstrução dos emissores de 0 a 100%. Para a condição de 50% de entupimento, 80% do comprimento da malha hidráulica apresentaram pressão superior à da classe de pressão da tubulação. O modelo matemático permitiu simular: (a a variação da rotação do conjunto moto-bomba diesel, como possível solução para controle da sobreelevação de pressão na malha hidráulica e (b a variação de pressão na rede, devido ao excesso de rotação no motor diesel (imprecisão no tacômetro. Quando se simularam a situação de 50% de entupimento e 2100 rotações min-1, 98% do comprimento da tubulação apresentaram pressão acima à da classe de pressão da tubulação.The present study attempts to evaluate the pressure increase in the hydraulic network of a micro-irrigation system when partial or total clogging of emitters occurs. The evaluated area was of 280 ha, with citrus irrigation based on subsurface auto-compensating drippers. The methodology utilized a mathematical model based on Bernoulli's equation, simulating the effects of different clogging rates on the network pressure. To evaluate the pressure variation in the system, the obstructions in the range from 0 to 100% were simulated. For the condition of 50% clogging, 80% of the total pipeline length presented hydraulic pressure more than the nominal pressure foreseen in the project. The mathematical model

  4. Greater Sudbury fuel efficient driving handbook

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-12-15

    Reducing the amount of fuel that people use for personal driving saves money, improves local air quality, and reduces personal contributions to climate change. This handbook was developed to be used as a tool for a fuel efficient driving pilot program in Greater Sudbury in 2009-2010. Specifically, the purpose of the handbook was to provide greater Sudbury drivers with information on how to drive and maintain their personal vehicles in order to maximize fuel efficiency. The handbook also provides tips for purchasing fuel efficient vehicles. It outlines the benefits of fuel maximization, with particular reference to reducing contributions to climate change; reducing emissions of air pollutants; safe driving; and money savings. Some tips for efficient driving are to avoid aggressive driving; use cruise control; plan trips; and remove excess weight. Tips for efficient winter driving are to avoid idling to warm up the engine; use a block heater; remove snow and ice; use snow tires; and check tire pressure. The importance of car maintenance and tire pressure was emphasized. The handbook also explains how fuel consumption ratings are developed by vehicle manufacturers. refs., figs.

  5. Advanced Performance Hydraulic Wind Energy

    Science.gov (United States)

    Jones, Jack A.; Bruce, Allan; Lam, Adrienne S.

    2013-01-01

    The Jet Propulsion Laboratory, California Institute of Technology, has developed a novel advanced hydraulic wind energy design, which has up to 23% performance improvement over conventional wind turbine and conventional hydraulic wind energy systems with 5 m/sec winds. It also has significant cost advantages with levelized costs equal to coal (after carbon tax rebate). The design is equally applicable to tidal energy systems and has passed preliminary laboratory proof-of-performance tests, as funded by the Department of Energy.

  6. Robust Prediction of Hydraulic Roughness

    Science.gov (United States)

    2011-03-01

    Manning’s n were required as input for further hydraulic analyses with HEC - RAS . HYDROCAL was applied to compare different estimates of resistance... River Restoration Science Synthesis (NRRSS) demonstrated that, in 2007, river and stream restoration projects and funding were at an all time high...behavior makes this parameter very difficult to quan- tify repeatedly and accurately. A fundamental concept of hydraulic theory in the context of river

  7. Transient flow analysis of the single cylinder for the control rod hydraulic driving system

    International Nuclear Information System (INIS)

    Sun, Xinming; Qin, Benke; Bo, Hanliang

    2017-01-01

    Highlights: • The control rod hydraulic driving system(CRHDS) is a new type of built-in control rod drive technology. The hydraulic cylinder is the main component of the CRHDS. • Transient flow phenomenon in the CRHDS is studied by experiments under different working conditions. • The working mechanism of the hydraulic cylinder step motion and the key characteristic parameters are analyzed based on the experimental results. - Abstract: The control rod hydraulic driving system (CRHDS) is a new type of built-in control rod drive technology. In the CRHDS the pulse flow from the pump into the hydraulic cylinder of the control rod hydraulic drive mechanism (CRHDM) is regulated by the integrated valve to perform the step motion of the reactor control rod. Transient flow occurs in the CRHDS during control rod step motion process which is studied by experiments. The time-history curves of flow rate, pressure and inner cylinder displacement were analyzed, and the results show that the water hammer pressure peak during the step-up motion is high, while there are no obvious pressure fluctuations in the corresponding step-down motion. In the step-up process, the pressure fluctuation amplitude increases with the increase of CRHDS driving pressure. The step-up time and the pressure increasing time before step-up decreases with the driving pressure. The step-up pressure increases with the driving pressure. In the step-down process, the step-down time, the step-down pressure and the pressure decreasing time before step-down do not change with the increase of the driving pressure. The experimental results lay the base for the working principle and vibration reduction analysis of the CRHDS and it’s also helpful for improvement of the working performance of the key facilities and instruments of the CRHDS loop.

  8. Prevalência de hipertensão arterial e fatores associados em estudantes de Ensino Médio de escolas públicas da Região Metropolitana do Recife, Pernambuco, Brasil, 2006 Prevalence of high blood pressure and associated factors in students from public schools in Greater Metropolitan Recife, Pernambuco State, Brazil, 2006

    Directory of Open Access Journals (Sweden)

    Betânia da Mata Ribeiro Gomes

    2009-02-01

    Full Text Available O objetivo deste estudo foi identificar a prevalência de hipertensão arterial sistêmica e fatores associados à saúde em adolescentes, por meio de estudo epidemiológico transversal de base populacional, realizado no período de abril a setembro de 2006, empregando amostragem estratificada segundo porte da escola e turnos. Utilizando-se o questionário Global School-based Student Health Survey, 1.878 estudantes de 29 escolas públicas da Região Metropolitana do Recife, Pernambuco, Brasil, foram investigados quanto a: idade; sexo; índice de massa corporal; consumo de frutas, verduras, álcool e tabaco; e pressão arterial, admitindo os parâmetros da Task Force Report on High Blood Pressure in Children and Adolescent, de 1996, para pressão arterial, do Centers for Disease Control and Prevention para estado nutricional. As prevalências de hipertensão arterial (medida apenas uma vez, sobrepeso e obesidade igualaram-se a 17,3%, 6,9% e 3,7%, respectivamente. Comportaram-se como fatores associados para hipertensão arterial: sexo masculino, obesidade, sobrepeso e falta de atividade física. Concluiu-se que o conhecimento dos fatores associados para hipertensão arterial em adolescentes poderá subsidiar campanhas de educação para a saúde.The aim of this study was to identify the prevalence of systemic arterial hypertension (high blood pressure and associated health factors in adolescents, using a cross-sectional, population-based, epidemiological design from April to September 2006, within a stratified sample according to school size and shift. Using the Portuguese version of the Global School-Based Student Health Survey questionnaire, 1,878 students from 29 public schools in Greater Metropolitan Recife, Pernambuco State, Brazil, were analyzed for: age, gender, body mass index, fruit, vegetable, alcohol, and tobacco consumption, as well as blood pressure, adopting the 1996 Task Force Report on High Blood Pressure in Children and

  9. Horizontal steam generator PGV-1000 thermal-hydraulic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O. [Skoda Company, Prague (Switzerland); Doubek, M. [Czech Technical Univ., Prague (Switzerland)

    1995-12-31

    A computer program for the steady state thermal-hydraulic analysis of horizontal steam generator PGV-1000 is presented. The program provides the capability to analyze steam generator PGV-1000 primary side flow and temperature distribution, primary side pressure drops, heat transfer between the primary and secondary sides and multidimensional heat flux distribution. A special attention is paid to the thermal-hydraulics of the secondary side. The code predicts 3-D distribution of the void fraction at the secondary side, mass redistribution under the submerged perforated sheet and the steam generator level profile. By means of developed computer program a detailed thermal-hydraulic study of the PGV-1000 has been carried out. A wide range of calculations has been performed and a set of important steam generator characteristics has been obtained. Some of them are presented in the paper. (orig.). 5 refs.

  10. Horizontal steam generator PGV-1000 thermal-hydraulic analysis

    International Nuclear Information System (INIS)

    Ubra, O.; Doubek, M.

    1995-01-01

    A computer program for the steady state thermal-hydraulic analysis of horizontal steam generator PGV-1000 is presented. The program provides the capability to analyze steam generator PGV-1000 primary side flow and temperature distribution, primary side pressure drops, heat transfer between the primary and secondary sides and multidimensional heat flux distribution. A special attention is paid to the thermal-hydraulics of the secondary side. The code predicts 3-D distribution of the void fraction at the secondary side, mass redistribution under the submerged perforated sheet and the steam generator level profile. By means of developed computer program a detailed thermal-hydraulic study of the PGV-1000 has been carried out. A wide range of calculations has been performed and a set of important steam generator characteristics has been obtained. Some of them are presented in the paper. (orig.)

  11. Horizontal steam generator PGV-1000 thermal-hydraulic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O [Skoda Company, Prague (Switzerland); Doubek, M [Czech Technical Univ., Prague (Switzerland)

    1996-12-31

    A computer program for the steady state thermal-hydraulic analysis of horizontal steam generator PGV-1000 is presented. The program provides the capability to analyze steam generator PGV-1000 primary side flow and temperature distribution, primary side pressure drops, heat transfer between the primary and secondary sides and multidimensional heat flux distribution. A special attention is paid to the thermal-hydraulics of the secondary side. The code predicts 3-D distribution of the void fraction at the secondary side, mass redistribution under the submerged perforated sheet and the steam generator level profile. By means of developed computer program a detailed thermal-hydraulic study of the PGV-1000 has been carried out. A wide range of calculations has been performed and a set of important steam generator characteristics has been obtained. Some of them are presented in the paper. (orig.). 5 refs.

  12. Determination of hydraulic properties of unsaturated soil via inverse modeling

    International Nuclear Information System (INIS)

    Kodesova, R.

    2004-01-01

    The method for determining the hydraulic properties of unsaturated soil with inverse modeling is presented. A modified cone penetrometer has been designed to inject water into the soil through a screen, and measure the progress of the wetting front with two tensiometer rings positioned above the screen. Cumulative inflow and pressure head readings are analyzed to obtain estimates of the hydraulic parameters describing K(h) and θ(h). Optimization results for tests at one side are used to demonstrate the possibility to evaluate either the wetting branches of the soil hydraulic properties, or the wetting and drying curves simultaneously, via analysis of different parts of the experiment. The optimization results are compared to the results of standard laboratory and field methods. (author)

  13. Design and performance characteristic analysis of servo valve-type water hydraulic poppet valve

    International Nuclear Information System (INIS)

    Park, Sung Hwan

    2009-01-01

    For water hydraulic system control, the flow or pressure control using high-speed solenoid valve controlled by PWM control method could be a good solution for prevention of internal leakage. However, since the PWM control of on-off valves cause extensive flow and pressure fluctuation, it is difficult to control the water hydraulic actuators precisely. In this study, the servo valve-type water hydraulic valve using proportional poppet as the main valve is designed and the performance characteristics of the servo valve-type water hydraulic valve are analyzed. Furthermore, it is demonstrated through experiments that a decline in control chamber pressure that follows the change of pilot flow is caused by the occurrence of cavitation around the proportional poppet, and that fundamental characteristics of the developed valve remain unaffected by the occurrence of cavitation

  14. The Greater Sekhukhune-CAPABILITY outreach project.

    Science.gov (United States)

    Gregersen, Nerine; Lampret, Julie; Lane, Tony; Christianson, Arnold

    2013-07-01

    The Greater Sekhukhune-CAPABILITY Outreach Project was undertaken in a rural district in Limpopo, South Africa, as part of the European Union-funded CAPABILITY programme to investigate approaches for capacity building for the translation of genetic knowledge into care and prevention of congenital disorders. Based on previous experience of a clinical genetic outreach programme in Limpopo, it aimed to initiate a district clinical genetic service in Greater Sekhukhune to gain knowledge and experience to assist in the implementation and development of medical genetic services in South Africa. Implementing the service in Greater Sekhukhune was impeded by a developing staff shortage in the province and pressure on the health service from the existing HIV/AIDS and TB epidemics. This situation underscores the need for health needs assessment for developing services for the care and prevention of congenital disorders in middle- and low-income countries. However, these impediments stimulated the pioneering of innovate ways to offer medical genetic services in these circumstances, including tele-teaching of nurses and doctors, using cellular phones to enhance clinical care and adapting and assessing the clinical utility of a laboratory test, QF-PCR, for use in the local circumstances.

  15. A hydraulic hybrid propulsion method for automobiles with self-adaptive system

    International Nuclear Information System (INIS)

    Wu, Wei; Hu, Jibin; Yuan, Shihua; Di, Chongfeng

    2016-01-01

    A hydraulic hybrid vehicle with the self-adaptive system is proposed. The mode-switching between the driving mode and the hydraulic regenerative braking mode is realised by the pressure cross-feedback control. Extensive simulated and tested results are presented. The control parameters are reduced and the energy efficiency can be increased by the self-adaptive system. The mode-switching response is fast. The response time can be adjusted by changing the controlling spool diameter of the hydraulic operated check valve in the self-adaptive system. The closing of the valve becomes faster with a smaller controlling spool diameter. The hydraulic regenerative braking mode can be achieved by changing the hydraulic transformer controlled angle. Compared with the convention electric-hydraulic system, the self-adaptive system for the hydraulic hybrid vehicle mode-switching has a higher reliability and a lower cost. The efficiency of the hydraulic regenerative braking is also increased. - Highlights: • A new hybrid system with a self-adaptive system for automobiles is presented. • The mode-switching is realised by the pressure cross-feedback control. • The energy efficiency can be increased with the self-adaptive system. • The control parameters are reduced with the self-adaptive system.

  16. Precision Force Control for an Electro-Hydraulic Press Machine

    Directory of Open Access Journals (Sweden)

    Hong-Ming Chen

    2014-08-01

    Full Text Available This thesis is primarily intended to design a PC-based control system to control the force of an electro-hydraulic servo press system for implementing precision force control. The main feature is to develop a composite control by using the relief valve and the flow servo valve. Using feedback from a force sensor, a fuzzy controller was designed with LabVIEW software as the system control core for achieving a precision force control for the hydraulic cylinder on its travel and output. The weakness of hydraulic systems is that hydraulic oil is compressible and prone to leaking, and its characteristics can vary with oil temperature, thus making it difficult for a general linear controller to achieve accurate control. Therefore, a fuzzy controller was designed with LabVIEW along with a NI-PCI_6221 interface card and a load cell to control the servo valve flow and the relief valve to control the pressure source. The testing results indicate that accurate force control output of an electro-hydraulic servo press system can be obtained.

  17. Hydraulic gradients in rock aquifers

    International Nuclear Information System (INIS)

    Dahlblom, P.

    1992-05-01

    This report deals with fractured rock as a host for deposits of hazardous waste. In this context the rock, with its fractures containing moving groundwater, is called the geological barrier. The desired properties of the geological barrier are low permeability to water, low hydraulic gradients and ability to retain matter dissolved in the water. The hydraulic gradient together with the permeability and the porosity determines the migration velocity. Mathematical modelling of the migration involves calculation of the water flow and the hydrodynamic dispersion of the contaminant. The porous medium approach can be used to calculate mean flow velocities and hydrodynamic dispersion of a large number of fractures are connected, which means that a large volume have to be considered. It is assumed that the porous medium approach can be applied, and a number of idealized examples are shown. It is assumed that the groundwater table is replenished by percolation at a constant rate. One-dimensional analytical calculations show that zero hydraulic gradients may exist at relatively large distance from the coast. Two-dimensional numerical calculations show that it may be possible to find areas with low hydraulic gradients and flow velocities within blocks surrounded by areas with high hydraulic conductivity. (au)

  18. Inherent Limitations of Hydraulic Tomography

    Science.gov (United States)

    Bohling, Geoffrey C.; Butler, J.J.

    2010-01-01

    We offer a cautionary note in response to an increasing level of enthusiasm regarding high-resolution aquifer characterization with hydraulic tomography. We use synthetic examples based on two recent field experiments to demonstrate that a high degree of nonuniqueness remains in estimates of hydraulic parameter fields even when those estimates are based on simultaneous analysis of a number of carefully controlled hydraulic tests. We must, therefore, be careful not to oversell the technique to the community of practicing hydrogeologists, promising a degree of accuracy and resolution that, in many settings, will remain unattainable, regardless of the amount of effort invested in the field investigation. No practically feasible amount of hydraulic tomography data will ever remove the need to regularize or bias the inverse problem in some fashion in order to obtain a unique solution. Thus, along with improving the resolution of hydraulic tomography techniques, we must also strive to couple those techniques with procedures for experimental design and uncertainty assessment and with other more cost-effective field methods, such as geophysical surveying and, in unconsolidated formations, direct-push profiling, in order to develop methods for subsurface characterization with the resolution and accuracy needed for practical field applications. Copyright ?? 2010 The Author(s). Journal compilation ?? 2010 National Ground Water Association.

  19. Selective perceptions of hydraulic fracturing.

    Science.gov (United States)

    Sarge, Melanie A; VanDyke, Matthew S; King, Andy J; White, Shawna R

    2015-01-01

    Hydraulic fracturing (HF) is a focal topic in discussions about domestic energy production, yet the American public is largely unfamiliar and undecided about the practice. This study sheds light on how individuals may come to understand hydraulic fracturing as this unconventional production technology becomes more prominent in the United States. For the study, a thorough search of HF photographs was performed, and a systematic evaluation of 40 images using an online experimental design involving N = 250 participants was conducted. Key indicators of hydraulic fracturing support and beliefs were identified. Participants showed diversity in their support for the practice, with 47 percent expressing low support, 22 percent high support, and 31 percent undecided. Support for HF was positively associated with beliefs that hydraulic fracturing is primarily an economic issue and negatively associated with beliefs that it is an environmental issue. Level of support was also investigated as a perceptual filter that facilitates biased issue perceptions and affective evaluations of economic benefit and environmental cost frames presented in visual content of hydraulic fracturing. Results suggested an interactive relationship between visual framing and level of support, pointing to a substantial barrier to common understanding about the issue that strategic communicators should consider.

  20. Birth of a hydraulic jump

    Science.gov (United States)

    Duchesne, Alexis; Bohr, Tomas; Andersen, Anders

    2017-11-01

    The hydraulic jump, i.e., the sharp transition between a supercritical and a subcritical free-surface flow, has been extensively studied in the past centuries. However, ever since Leonardo da Vinci asked it for the first time, an important question has been left unanswered: How does a hydraulic jump form? We present an experimental and theoretical study of the formation of stationary hydraulic jumps in centimeter wide channels. Two starting situations are considered: The channel is, respectively, empty or filled with liquid, the liquid level being fixed by the wetting properties and the boundary conditions. We then change the flow-rate abruptly from zero to a constant value. In an empty channel, we observe the formation of a stationary hydraulic jump in a two-stage process: First, the channel fills by the advancing liquid front, which undergoes a transition from supercritical to subcritical at some position in the channel. Later the influence of the downstream boundary conditions makes the jump move slowly upstream to its final position. In the pre-filled channel, the hydraulic jump forms at the injector edge and then moves downstream to its final position.

  1. [Autoerotic fatalities in Greater Dusseldorf].

    Science.gov (United States)

    Hartung, Benno; Hellen, Florence; Borchard, Nora; Huckenbeck, Wolfgang

    2011-01-01

    Autoerotic fatalities in the Greater Dusseldorf area correspond to the relevant medicolegal literature. Our results included exclusively young to middle-aged, usually single men who were found dead in their city apartments. Clothing and devices used showed a great variety. Women's or fetish clothing and complex shackling or hanging devices were disproportionately frequent. In most cases, death occurred due to hanging or ligature strangulation. There was no increased incidence of underlying psychiatric disorders. In most of the deceased no or at least no remarkable alcohol intoxication was found. Occasionally, it may be difficult to reliably differentiate autoerotic accidents, accidents occurring in connection with practices of bondage & discipline, dominance & submission (BDSM) from natural death, suicide or homicide.

  2. Planning for greater confinement disposal

    International Nuclear Information System (INIS)

    Gilbert, T.L.; Luner, C.; Meshkov, N.K.; Trevorrow, L.E.; Yu, C.

    1985-01-01

    A report that provides guidance for planning for greater-confinement disposal (GCD) of low-level radioactive waste is being prepared. The report addresses procedures for selecting a GCD technology and provides information for implementing these procedures. The focus is on GCD; planning aspects common to GCD and shallow-land burial are covered by reference. Planning procedure topics covered include regulatory requirements, waste characterization, benefit-cost-risk assessment and pathway analysis methodologies, determination of need, waste-acceptance criteria, performance objectives, and comparative assessment of attributes that support these objectives. The major technologies covered include augered shafts, deep trenches, engineered structures, hydrofracture, improved waste forms, and high-integrity containers. Descriptive information is provided, and attributes that are relevant for risk assessment and operational requirements are given. 10 refs., 3 figs., 2 tabs

  3. Reliability of Source Mechanisms for a Hydraulic Fracturing Dataset

    Science.gov (United States)

    Eyre, T.; Van der Baan, M.

    2016-12-01

    Non-double-couple components have been inferred for induced seismicity due to fluid injection, yet these components are often poorly constrained due to the acquisition geometry. Likewise non-double-couple components in microseismic recordings are not uncommon. Microseismic source mechanisms provide an insight into the fracturing behaviour of a hydraulically stimulated reservoir. However, source inversion in a hydraulic fracturing environment is complicated by the likelihood of volumetric contributions to the source due to the presence of high pressure fluids, which greatly increases the possible solution space and therefore the non-uniqueness of the solutions. Microseismic data is usually recorded on either 2D surface or borehole arrays of sensors. In many cases, surface arrays appear to constrain source mechanisms with high shear components, whereas borehole arrays tend to constrain more variable mechanisms including those with high tensile components. The abilities of each geometry to constrain the true source mechanisms are therefore called into question.The ability to distinguish between shear and tensile source mechanisms with different acquisition geometries is investigated using synthetic data. For both inversions, both P- and S- wave amplitudes recorded on three component sensors need to be included to obtain reliable solutions. Surface arrays appear to give more reliable solutions due to a greater sampling of the focal sphere, but in reality tend to record signals with a low signal to noise ratio. Borehole arrays can produce acceptable results, however the reliability is much more affected by relative source-receiver locations and source orientation, with biases produced in many of the solutions. Therefore more care must be taken when interpreting results.These findings are taken into account when interpreting a microseismic dataset of 470 events recorded by two vertical borehole arrays monitoring a horizontal treatment well. Source locations and

  4. Hydraulic Power Plant Machine Dynamic Diagnosis

    Directory of Open Access Journals (Sweden)

    Hans Günther Poll

    2006-01-01

    Full Text Available A method how to perform an entire structural and hydraulic diagnosis of prototype Francis power machines is presented and discussed in this report. Machine diagnosis of Francis units consists on a proper evaluation of acquired mechanical, thermal and hydraulic data obtained in different operating conditions of several rotary and non rotary machine components. Many different physical quantities of a Francis machine such as pressure, strains, vibration related data, water flow, air flow, position of regulating devices and displacements are measured in a synchronized way so that a relation of cause an effect can be developed for each operating condition and help one to understand all phenomena that are involved with such kind of machine. This amount of data needs to be adequately post processed in order to allow correct interpretation of the machine dynamics and finally these data must be compared with the expected calculated data not only to fine tuning the calculation methods but also to accomplish fully understanding of the influence of the water passages on such machines. The way how the power plant owner has to operate its Francis machines, many times also determined by a central dispatcher, has a high influence on the fatigue life time of the machine components. The diagnostic method presented in this report helps one to understand the importance of adequate operation to allow a low maintenance cost for the entire power plant. The method how to acquire these quantities is discussed in details together with the importance of correct sensor balancing, calibration and adequate correlation with the physical quantities. Typical results of the dynamic machine behavior, with adequate interpretation, obtained in recent measurement campaigns of some important hydraulic turbines were presented. The paper highlights the investigation focus of the hydraulic machine behavior and how to tailor the measurement strategy to accomplish all goals. Finally some

  5. Water hydraulic applications in hazardous environments

    International Nuclear Information System (INIS)

    Siuko, M.; Koskinen, K.T.; Vilenius, M.J.

    1996-01-01

    Water hydraulic technology provides several advantages for devices operating in critical environment. Though water hydraulics has traditionally been used in very rough applications, gives recent strong development of components possibility to build more sophisticated applications and devices with similar capacity and control properties than those of oil hydraulics without the disadvantages of oil hydraulic systems. In this paper, the basic principles, possibilities and advantages of water hydraulics are highlighted, some of the most important design considerations are presented and recent developments of water hydraulic technology are presented. Also one interesting application area, ITER fusion reactor remote handling devices, are discussed. (Author)

  6. Hydraulic lifter for an underwater drilling rig

    Energy Technology Data Exchange (ETDEWEB)

    Garan' ko, Yu L

    1981-01-15

    A hydraulic lifter is suggested for an underwater drilling rig. It includes a base, hydraulic cylinders for lifting the drilling pipes connected to the clamp holder and hydraulic distributor. In order to simplify the design of the device, the base is made with a hollow chamber connected to the rod cavities and through the hydraulic distributor to the cavities of the hydraulic cylinders for lifting the drilling pipes. The hydraulic distributor is connected to the hydrosphere through the supply valve with control in time or by remote control. The base is equipped with reverse valves whose outlets are on the support surface of the base.

  7. Controls of Hydraulic Wind Turbine

    Directory of Open Access Journals (Sweden)

    Zhang Yin

    2016-01-01

    Full Text Available In this paper a hydraulic wind turbine generator system was proposed based on analysis the current wind turbines technologies. The construction and principles were introduced. The mathematical model was verified using MATLAB and AMsim. A displacement closed loop of swash plate of motor and a speed closed loop of generator were setup, a PID control is introduced to maintain a constant speed and fixed frequency at wind turbine generator. Simulation and experiment demonstrated that the system can connect grid to generate electric and enhance reliability. The control system demonstrates a high performance speed regulation and effectiveness. The results are great significant to design a new type hydraulic wind turbine system.

  8. Disposal of waste by hydraulic fracturing

    International Nuclear Information System (INIS)

    Tamura, T.; Weeren, H.

    1984-01-01

    Liquid radioactive waste solutions at the Oak Ridge National Laboratory (ORNL) have been disposed of for nearly 20 years by preparing a slurry, injecting it into bedding plane fractures formed in low-permeability shale, and allowing the slurry to set into a solid. Three major considerations are required for this method: a rock formation that forms horizontal or bedding plane fractures and is highly impermeable, a plant facility that can develop sufficient hydraulic pressure to fracture the rock and to inject the slurry, and a slurry that can be pumped into the fracture and that will set, preferably, into a low-leaching solid. The requirements and desirable conditions of the formation, the process and facility as used for radioactive waste disposal, and the mix formulation and slurry properties that were required for injection and solidification are described. The intent of this paper is to stimulate interest in this technique for possible application to nonnuclear wastes

  9. Wind tunnel experiments to prove a hydraulic passive rotor speed control concept for variable speed wind turbines (poster)

    NARCIS (Netherlands)

    Diepeveen, N.F.B.; Jarquin Laguna, A.

    2012-01-01

    As alternative to geared and direct drive solutions, fluid power drive trains are being developed by several institutions around the world. The common configuration is where the wind turbine rotor is coupled to a hydraulic pump. The pump is connected through a high pressure line to a hydraulic motor

  10. Implications of the "observer effect" on modelling a long-term pumping test with hydraulically conductive boreholes in a discrete fracture network system.

    Science.gov (United States)

    Holton, D.; Frampton, A.; Cvetkovic, V.

    2006-12-01

    The Onkalo underground research facility for rock characterisation for nuclear waste disposal is located at Olkiluoto island, just off the Finnish coast in the Baltic Sea. Prior to the start of the excavation of the Onkalo facility, an extensive amount of hydraulic data has been collected during various pumping experiments from a large number of boreholes placed throughout an area of approximately 10 km2, reaching depths of 1000 meters below sea level. In particular, the hydraulic borehole data includes classical measurements of pressure, but also new measurements of flow rate and flow direction in boreholes (so called flow-logging). These measurements indicate large variations in heterogeneity and are a clear reflection of the discrete nature of the system. Here we present results from an ongoing project which aims to explore and asses the implications of these new flow-logging measurements to site descriptive modelling and modelling at performance assessment scales. The main challange of the first phase of this project is to obtain a greater understanding of a strongly heterogenious and anisotropic groundwater system in which open boreholes are located; that is, a system in which the observation boreholes themselves create new hydraulic conductive features of the groundwater system. The results presented are from recent hydraulic flow modelling simulations with a combined continuous porous media and discrete fracture network approach using a commercial finite-element software. An advantage of this approach is we may adapt a continuum mesh on the regional scale, were only a few conductive features are known, together with a local scale discrete fracture network approach, where detailed site-investigation has revealed a large amount of conductive features. Current findings indicate the system is sensitive to certain combinations of hydraulic features, and we quantify the significance of including these variations in terms of their implications for reduction of

  11. Effect of depletion of interstitial hyaluronan on hydraulic conductance in rabbit knee synovium

    Science.gov (United States)

    Coleman, P J; Scott, D; Abiona, A; Ashhurst, D E; Mason, R M; Levick, J R

    1998-01-01

    The hydraulic resistance of the synovial lining to fluid outflow from a joint cavity () is important for the retention of intra-articular lubricant. The resistance has been attributed in part to extracellular glycosaminoglycans, including hyaluronan and chondroitin sulphates. Increased permeability in joints infused with testicular hyaluronidase, which digests both chondroitin sulphates and hyaluronan, supports this view. In this study the importance of interstitial hyaluronan per se was assessed using leech and Streptomyces hyaluronidases, which degrade only hyaluronan. Ringer solution was infused into the knee joint cavity of anaesthetized rabbits for 30 min, with or without hyaluronidase, after which intra-articular pressure (Pj) was raised and the relation between pressure and outflow determined. Treatment with Streptomyces, leech or testicular hyaluronidases increased the fluid escape rates by similar factors, namely 4- to 6-fold. After Streptomyces hyaluronidase treatment the slope d/dPj, which at low pressures represents synovial hydraulic conductance, increased from a control of 0.90 ± 0.20 μl min−1 cmH2O−1 (mean ± s.e.m., n = 6) to 4.52 ± 0.70 μl min−1 cmH2O−1. The slope d/dPj increased to a similar level after testicular hyaluronidase, namely to 4.14 ± 1.06 μl min−1 cmH2O−1 (control, 0.54 ± 0.24 μl min−1 cmH2O−1). Streptomyces and leech hyaluronidases were as effective as testicular hyaluronidase (no statistically significant differences) despite differences in substrate specificity. It was shown using histochemical and immunohistochemical techniques that hyaluronan was removed from the synovium by leech, Streptomyces and testicular hyaluronidases. The binding of antibodies 2-B-6 and 3-B-3 showed that the core proteins of the chondroitin sulphate proteoglycans remained intact after treatment with hyaluronidases, and the binding of 5-D-4 showed that keratan sulphate was unaffected. An azocasein digestion assay confirmed that the

  12. Thermal hydraulic simulation of the CANDU nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Athos M.S.S. de; Ramos, Mario C.; Costa, Antonella L.; Fernandes, Gustavo H.N., E-mail: athos1495@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Instituto Nacional de Ciência e Tecnologia de Reatores Nucleares Inovadores (INCT/CNPq), Rio de janeiro, RJ (Brazil)

    2017-07-01

    The CANDU (Canada Deuterium Uranium) is a Canadian-designed power reactor of PHWR type (Pressurized Heavy Water Reactor) that uses heavy water (deuterium oxide) for moderator and coolant, and natural uranium for fuel. There are about 47 reactors of this type in operation around the world generating more than 23 GWe, highlighting the importance of this kind of device. In this way, the main purpose of this study is to develop a thermal hydraulic model for a CANDU reactor to aggregate knowledge in this line of research. In this way, a core modeling was performed using RELAP5-3D code. Results were compared with reference data to verify the model behavior in steady state operation. Thermal hydraulic parameters as temperature, pressure and mass flow rate were verified and the results are in good agreement with reference data, as it is being presented in this work. (author)

  13. Motion simulation of hydraulic driven safety rod using FSI method

    International Nuclear Information System (INIS)

    Jung, Jaeho; Kim, Sanghaun; Yoo, Yeonsik; Cho, Yeonggarp; Kim, Jong In

    2013-01-01

    Hydraulic driven safety rod which is one of them is being developed by Division for Reactor Mechanical Engineering, KAERI. In this paper the motion of this rod is simulated by fluid structure interaction (FSI) method before manufacturing for design verification and pump sizing. A newly designed hydraulic driven safety rod which is one of reactivity control mechanism is simulated using FSI method for design verification and pump sizing. The simulation is done in CFD domain with UDF. The pressure drop is changed slightly by flow rates. It means that the pressure drop is mainly determined by weight of moving part. The simulated velocity of piston is linearly proportional to flow rates so the pump can be sized easily according to the rising and drop time requirement of the safety rod using the simulation results

  14. Women at greater risk of HIV infection.

    Science.gov (United States)

    Mahathir, M

    1997-04-01

    Although many people believe that mainly men get infected with HIV/AIDS, women are actually getting infected at a faster rate than men, especially in developing countries, and suffer more from the adverse impact of AIDS. As of mid-1996, the Joint UN Program on AIDS estimated that more than 10 million of the 25 million adults infected with HIV since the beginning of the epidemic are women. The proportion of HIV-positive women is growing, with almost half of the 7500 new infections daily occurring among women. 90% of HIV-positive women live in a developing country. In Asia-Pacific, 1.4 million women have been infected with HIV out of an estimated total 3.08 million adults from the late 1970s until late 1994. Biologically, women are more vulnerable than men to infection because of the greater mucus area exposed to HIV during penile penetration. Women under age 17 years are at even greater risk because they have an underdeveloped cervix and low vaginal mucus production. Concurrent sexually transmitted diseases increase the risk of HIV transmission. Women's risk is also related to their exposure to gender inequalities in society. The social and economic pressures of poverty exacerbate women's risk. Prevention programs are discussed.

  15. Waste management in Greater Vancouver

    Energy Technology Data Exchange (ETDEWEB)

    Carrusca, K. [Greater Vancouver Regional District, Burnaby, BC (Canada); Richter, R. [Montenay Inc., Vancouver, BC (Canada)]|[Veolia Environmental Services, Vancouver, BC (Canada)

    2006-07-01

    An outline of the Greater Vancouver Regional District (GVRD) waste-to-energy program was presented. The GVRD has an annual budget for solid waste management of $90 million. Energy recovery revenues from solid waste currently exceed $10 million. Over 1,660,00 tonnes of GVRD waste is recycled, and another 280,000 tonnes is converted from waste to energy. The GVRD waste-to-energy facility combines state-of-the-art combustion and air pollution control, and has processed over 5 million tonnes of municipal solid waste since it opened in 1988. Its central location minimizes haul distance, and it was originally sited to utilize steam through sales to a recycle paper mill. The facility has won several awards, including the Solid Waste Association of North America award for best facility in 1990. The facility focuses on continual improvement, and has installed a carbon injection system; an ammonia injection system; a flyash stabilization system; and heat capacity upgrades in addition to conducting continuous waste composition studies. Continuous air emissions monitoring is also conducted at the plant, which produces a very small percentage of the total air emissions in metropolitan Vancouver. The GVRD is now seeking options for the management of a further 500,000 tonnes per year of solid waste, and has received 23 submissions from a range of waste energy technologies which are now being evaluated. It was concluded that waste-to-energy plants can be located in densely populated metropolitan areas and provide a local disposal solution as well as a source of renewable energy. Other GVRD waste reduction policies were also reviewed. refs., tabs., figs.

  16. Hydraulic performance of a multistage array of advanced centrifugal contactors

    International Nuclear Information System (INIS)

    Hodges, M.E.

    1984-01-01

    The hydraulic characteristics of an advanced design centrifugal contactor array have been determined at the Savannah River Laboratory (SRL). The advanced design utilizes couette mixing (Taylor vortices) in the annulus between the rotating and stationary bowls. Excellent phase separation over a wide range of flow conditions was obtained. Interfaces within an entire eight-stage array were controlled with a single weir air pressure. 2 references, 5 figures

  17. The Potential Impacts of Hydraulic Fracturing on Agriculture

    OpenAIRE

    Beng Ong

    2014-01-01

    Hydraulic fracturing (or “fracking”) is a method of extracting oil and natural gas trapped in deep rock layers underground by pumping water, sand, and other chemicals/additives at high pressures into a well drilled vertically, and then horizontally into the rocks.Advocates of fracking in U.S. have skillfully positioned domestic natural gas as a sensible alternative energy to the country’s goals of reducing carbon emissions and dependence on foreign oil, while simultaneously creating jobs loca...

  18. Study of effect of in-line hydropneumatic accumulators on output characteristics of hydraulic hammer

    Science.gov (United States)

    Redelin, R. A.; Kravchenko, V. A.; Kamanin, Y. N.; Panichkin, A. V.; Bozhanov, A. A.

    2017-10-01

    The article presents the results of studies of the effect of in-line hydropneumatic accumulators on the output parameters of a hydraulic hammer during their joint operation. Based on mathematical modeling, computational experiments were performed and the output characteristics of the hammer, depending on the design and operating parameters of the in-line hydropneumatic accumulators, were obtained. It was established that for the most effective operation of the hammer, the precharge pressure of the pressure line hydropneumatic accumulator should be 70-80% of the working pressure of the hydraulic system. The utilization of a hydropneumatic accumulator without special additional devices in the discharge line is impractical.

  19. Hydraulically-actuated operating system for an electric circuit breaker

    Science.gov (United States)

    Barkan, Philip; Imam, Imdad

    1978-01-01

    This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A vent is located hydraulically between the actuating space and the valve for affording communication between said actuating space and a low pressure region. Flow control means is provided for restricting leakage through said vent to a rate that prevents said leakage from substantially detracting from the development of pressure within said actuatng space during the period from initial opening of the valve to the time when said piston has moved through most of its opening stroke. Following such period and while the valve is still open, said flow control means allows effective leakage through said vent. The accumulator has a limited capacity that results in the pressure within said actuating space decaying promptly to a low value as a result of effective leakage through said vent after the piston has moved through a circuit-breaker opening stroke and while the valve is in its open state. Means is provided for resetting the valve to its closed state in response to said pressure decay in the actuating space.

  20. An XFEM Model for Hydraulic Fracturing in Partially Saturated Rocks

    Directory of Open Access Journals (Sweden)

    Salimzadeh Saeed

    2016-01-01

    Full Text Available Hydraulic fracturing is a complex multi-physics phenomenon. Numerous analytical and numerical models of hydraulic fracturing processes have been proposed. Analytical solutions commonly are able to model the growth of a single hydraulic fracture into an initially intact, homogeneous rock mass. Numerical models are able to analyse complex problems such as multiple hydraulic fractures and fracturing in heterogeneous media. However, majority of available models are restricted to single-phase flow through fracture and permeable porous rock. This is not compatible with actual field conditions where the injected fluid does not have similar properties as the host fluid. In this study we present a fully coupled hydro-poroelastic model which incorporates two fluids i.e. fracturing fluid and host fluid. Flow through fracture is defined based on lubrication assumption, while flow through matrix is defined as Darcy flow. The fracture discontinuity in the mechanical model is captured using eXtended Finite Element Method (XFEM while the fracture propagation criterion is defined through cohesive fracture model. The discontinuous matrix fluid velocity across fracture is modelled using leak-off loading which couples fracture flow and matrix flow. The proposed model has been discretised using standard Galerkin method, implemented in Matlab and verified against several published solutions. Multiple hydraulic fracturing simulations are performed to show the model robustness and to illustrate how problem parameters such as injection rate and rock permeability affect the hydraulic fracturing variables i.e. injection pressure, fracture aperture and fracture length. The results show the impact of partial saturation on leak-off and the fact that single-phase models may underestimate the leak-off.

  1. Effect of fin-endwall fillet on thermal hydraulic performance of airfoil printed circuit heat exchanger

    International Nuclear Information System (INIS)

    Ma, Ting; Xin, Fei; Li, Lei; Xu, Xiang-yang; Chen, Yi-tung; Wang, Qiu-wang

    2015-01-01

    Printed circuit heat exchanger (PCHE) is recommended to be used for intermediate heat exchanger in Very High Temperature Reactor (VHTR). One of the key features is that it is manufactured by the photochemical etching in order to maintain the internal structure and metal properties. In this paper, a photochemical etching experiment is conducted to manufacture the airfoil PCHE plate. The result indicates that the airfoil fin is not an ideal airfoil profile, but has a fin-endwall fillet. For the purpose of simplifying the numerical model and saving computational time, a validated model with a single fluid is used to further study the effect of fin-endwall fillet on the thermal hydraulic performance of airfoil PCHE. It is found that the fin-endwall fillet can increase the heat transfer and pressure drop in the cases with the non-dimensional longitudinal pitch being 1.63. The effect of fin-endwall fillet on thermal hydraulic performance decreases with the increase of transverse pitch, but the longitudinal pitch has little effect when the non-dimensional longitudinal pitch is greater than 1.88. In the studied cases, the maximum difference of Nusselt number and friction factor between the two models with and without fin-endwall fillet is up to 6.7% and 6.4%. - Highlights: • Fillets are formed in the endwall of airfoil fins during the photochemical etching. • Two-fluid model can be replaced by single-fluid model to perform simulation. • Fin-endwall fillet can increase heat transfer and pressure drop at ζ_l = 1.63. • Effect of fin-endwall fillet decreases as transverse pitch increases at ζ_l = 1.63. • Longitudinal pitch has little effect at ζ_l ≥ 1.88.

  2. Design of hydraulic recuperation unit

    Directory of Open Access Journals (Sweden)

    Jandourek Pavel

    2016-01-01

    Full Text Available This article deals with design and measurement of hydraulic recuperation unit. Recuperation unit consist of radial turbine and axial pump, which are coupled on the same shaft. Speed of shaft with impellers are 6000 1/min. For economic reasons, is design of recuperation unit performed using commercially manufactured propellers.

  3. Tree Hydraulics: How Sap Rises

    Science.gov (United States)

    Denny, Mark

    2012-01-01

    Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

  4. Tubing Cutter is Activated Hydraulically

    Science.gov (United States)

    Mcsmith, D. G.; Richardson, J. I.

    1983-01-01

    Hydraulically-actuated tubing cutter severs tubing when operator squeezes handle grip. "Gooseneck" extension enables cutter to be used in areas where accessiblity is limited. Cutter has potential as flight-line tool and is useful in automobile and fire rescue work.

  5. Hydraulics submission for Middlesex County, NJ

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data include spatial datasets and data tables necessary for documenting the hydraulic procedures for estimating base flood elevation for a flood insurance...

  6. DCS Hydraulics Submittal, Bullock County, Alabama, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  7. DCS Hydraulics Submittal, Butler County, Alabama, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  8. DCS Hydraulics Submittal, Covington County, Alabama, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  9. CRITICALITY CURVES FOR PLUTONIUM HYDRAULIC FLUID MIXTURES

    International Nuclear Information System (INIS)

    WITTEKIND WD

    2007-01-01

    This Calculation Note performs and documents MCNP criticality calculations for plutonium (100% 239 Pu) hydraulic fluid mixtures. Spherical geometry was used for these generalized criticality safety calculations and three geometries of neutron reflection are: (sm b ullet)bare, (sm b ullet)1 inch of hydraulic fluid, or (sm b ullet)12 inches of hydraulic fluid. This document shows the critical volume and critical mass for various concentrations of plutonium in hydraulic fluid. Between 1 and 2 gallons of hydraulic fluid were discovered in the bottom of HA-23S. This HA-23S hydraulic fluid was reported by engineering to be Fyrquel 220. The hydraulic fluid in GLovebox HA-23S is Fyrquel 220 which contains phosphorus. Critical spherical geometry in air is calculated with 0 in., 1 in., or 12 inches hydraulic fluid reflection

  10. Hydraulics submission for Gloucester County, NJ

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data include spatial datasets and data tables necessary for documenting the hydraulic procedures for estimating base flood elevation for a flood insurance...

  11. Thermal-hydraulic analysis for wire-wrapped PWR cores

    Energy Technology Data Exchange (ETDEWEB)

    Diller, P. [General Electric Company, 3901 Castle Hayne Rd., Wilmington, NC 28401 (United States)], E-mail: pdiller@gmail.com; Todreas, N. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)], E-mail: todreas@mit.edu; Hejzlar, P. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2009-08-15

    This work focuses on the steady-state and transient thermal-hydraulic analyses for PWR cores using wire wraps in a hexagonal array with either U (45% w/o)-ZrH{sub 1.6} (referred to as U-ZrH{sub 1.6}) or UO{sub 2} fuels. Equivalences (thermal-hydraulic and neutronic) were created between grid spacer and wire wrap designs, and were used to apply results calculated for grid spacers to wire wrap designs. Design limits were placed on the pressure drop, critical heat flux (CHF), fuel and cladding temperature and vibrations. The vibrations limits were imposed for flow-induced vibrations (FIV) and thermal-hydraulic vibrations (THV). The transient analysis examined an overpower accident, loss of coolant accident (LOCA) and loss of flow accident (LOFA). The thermal-hydraulic performance of U-ZrH{sub 1.6} and UO{sub 2} were found very similar. Relative to grid spacer designs, wire wrap designs were found to have smaller fretting wear, substantially lower pressure drop and higher CHF. As a result, wire wrap cores were found to offer substantially higher maximum powers than grid spacer cores, allowing for a 25% power increase relative to the grid spacer uprate [Shuffler, C.A., Malen, J.A., Trant, J.M., Todreas, N.E., 2009a. Thermal-hydraulic analysis for grid supported and inverted fueled PWR cores. Nuclear Technology (this special issue devoted to hydride fuel in LWRs)] and a 58% power increase relative to the reference core.

  12. Turbulent Motion of Liquids in Hydraulic Resistances with a Linear Cylindrical Slide-Valve

    Directory of Open Access Journals (Sweden)

    C. Velescu

    2015-01-01

    Full Text Available We analyze the motion of viscous and incompressible liquids in the annular space of controllable hydraulic resistances with a cylindrical linear slide-valve. This theoretical study focuses on the turbulent and steady-state motion regimes. The hydraulic resistances mentioned above are the most frequent type of hydraulic resistances used in hydraulic actuators and automation systems. To study the liquids’ motion in the controllable hydraulic resistances with a linear cylindrical slide-valve, the report proposes an original analytic method. This study can similarly be applied to any other type of hydraulic resistance. Another purpose of this study is to determine certain mathematical relationships useful to approach the theoretical functionality of hydraulic resistances with magnetic controllable fluids as incompressible fluids in the presence of a controllable magnetic field. In this report, we established general analytic equations to calculate (i velocity and pressure distributions, (ii average velocity, (iii volume flow rate of the liquid, (iv pressures difference, and (v radial clearance.

  13. Hydraulic performance numerical simulation of high specific speed mixed-flow pump based on quasi three-dimensional hydraulic design method

    International Nuclear Information System (INIS)

    Zhang, Y X; Su, M; Hou, H C; Song, P F

    2013-01-01

    This research adopts the quasi three-dimensional hydraulic design method for the impeller of high specific speed mixed-flow pump to achieve the purpose of verifying the hydraulic design method and improving hydraulic performance. Based on the two families of stream surface theory, the direct problem is completed when the meridional flow field of impeller is obtained by employing iterative calculation to settle the continuity and momentum equation of fluid. The inverse problem is completed by using the meridional flow field calculated in the direct problem. After several iterations of the direct and inverse problem, the shape of impeller and flow field information can be obtained finally when the result of iteration satisfies the convergent criteria. Subsequently the internal flow field of the designed pump are simulated by using RANS equations with RNG k-ε two-equation turbulence model. The static pressure and streamline distributions at the symmetrical cross-section, the vector velocity distribution around blades and the reflux phenomenon are analyzed. The numerical results show that the quasi three-dimensional hydraulic design method for high specific speed mixed-flow pump improves the hydraulic performance and reveal main characteristics of the internal flow of mixed-flow pump as well as provide basis for judging the rationality of the hydraulic design, improvement and optimization of hydraulic model

  14. Hydraulic conductivity of rock fractures

    International Nuclear Information System (INIS)

    Zimmerman, R.W.; Bodvarsson, G.S.

    1994-10-01

    Yucca Mountain, Nevada contains numerous geological units that are highly fractured. A clear understanding of the hydraulic conductivity of fractures has been identified as an important scientific problem that must be addressed during the site characterization process. The problem of the flow of a single-phase fluid through a rough-walled rock fracture is discussed within the context of rigorous fluid mechanics. The derivation of the cubic law is given as the solution to the Navier-Stokes equations for flow between smooth, parallel plates, the only fracture geometry that is amenable to exact treatment. The various geometric and kinetic conditions that are necessary in order for the Navier-Stokes equations to be replaced by the more tractable lubrication or Hele-Shaw equations are studied and quantified. Various analytical and numerical results are reviewed pertaining to the problem of relating the effective hydraulic aperture to the statistics of the aperture distribution. These studies all lead to the conclusion that the effective hydraulic aperture is always less than the mean aperture, by a factor that depends on the ratio of the mean value of the aperture to its standard deviation. The tortuosity effect caused by regions where the rock walls are in contact with each other is studied using the Hele-Shaw equations, leading to a simple correction factor that depends on the area fraction occupied by the contact regions. Finally, the predicted hydraulic apertures are compared to measured values for eight data sets from the literature for which aperture and conductivity data were available on the same fracture. It is found that reasonably accurate predictions of hydraulic conductivity can be made based solely on the first two moments of the aperture distribution function, and the proportion of contact area. 68 refs

  15. Subsea Hydraulic Leakage Detection and Diagnosis

    OpenAIRE

    Stavenes, Thomas

    2010-01-01

    The motivation for this thesis is reduction of hydraulic emissions, minimizing of process emergency shutdowns, exploitation of intervention capacity, and reduction of costs. Today, monitoring of hydraulic leakages is scarce and the main way to detect leakage is the constant need for filling of hydraulic fluid to the Hydraulic Power Unit (HPU). Leakage detection and diagnosis has potential, which would be adressed in this thesis. A strategy towards leakage detection and diagnosis is given....

  16. Study on the application of energy storage system in offshore wind turbine with hydraulic transmission

    International Nuclear Information System (INIS)

    Fan, Yajun; Mu, Anle; Ma, Tao

    2016-01-01

    Highlights: • Hydraulic offshore wind turbine is capable of outputting near constant power. • Open loop hydraulic transmission uses seawater as the working fluid. • Linear control strategy distributes total flow according to demand and supply. • Constant pressure hydraulic accumulator stores/releases the surplus energy. • Simulations show the dynamic performance of the hybrid system. - Abstract: A novel offshore wind turbine comprising fluid power transmission and energy storage system is proposed. In this wind turbine, the conventional mechanical transmission is replaced by an open-loop hydraulic system, in which seawater is sucked through a variable displacement pump in nacelle connected directly with the rotor and utilized to drive a Pelton turbine installed on the floating platform. Aiming to smooth and stabilize the output power, an energy storage system with the capability of flexible charging and discharging is applied. The related mathematical model is developed, which contains some sub-models that are categorized as the wind turbine rotor, hydraulic pump, transmission pipeline, proportional valve, accumulator and hydraulic turbine. A linear control strategy is adopted to distribute the flow out of the proportional valve through comparing the demand power with captured wind energy by hydraulic pump. Ultimately, two time domain simulations demonstrate the operation of the hybrid system when the hydraulic accumulator is utilized and show how this system can be used for load leveling and stabilizing the output power.

  17. Operating problem of low specific speed pumps operating in closed hydraulic loop

    International Nuclear Information System (INIS)

    Rajput, A.K.

    1979-01-01

    Results of the studies of pressure pulsations caused by the centrifugal pump driving a typical sodium test loop are presented. The method of characteristics has been used for solving the equations of unsteady fluid flow in closed hydraulic loops with various boundary points, important of which are pump, control valve and heater tank (acting hydraulically as surge tank). Mathematical and computational models used for calculations are described. (M.G.B.)

  18. New empirical relationship between grain size distribution and hydraulic conductivity for ephemeral streambed sediments

    KAUST Repository

    Rosas, Jorge

    2014-07-19

    Grain size distribution, porosity, and hydraulic conductivity were determined for 39 sediment samples collected from ephemeral streams (wadis) in western Saudi Arabia. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations commonly used to estimate hydraulic conductivity from grain size analyses. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly with the measured hydraulic conductivity values. Modifications of the empirical equations, including changes to special coefficients and statistical offsets, were made to produce modified equations that considerably improved the hydraulic conductivity estimates from grain size data for wadi sediments. The Chapuis, Hazen, Kozeny, Slichter, Terzaghi, and Barr equations produced the best correlations, but still had relatively high predictive errors. The Chapius equation was modified for wadi sediments by incorporating mud percentage and the standard deviation (in phi units) into a new equation that reduced the predicted hydraulic conductivity error to ±14.1 m/day. The equation is best applied to ephemeral stream samples that have hydraulic conductive values greater than 2 m/day.

  19. New empirical relationship between grain size distribution and hydraulic conductivity for ephemeral streambed sediments

    KAUST Repository

    Rosas, Jorge; Jadoon, Khan; Missimer, Thomas M.

    2014-01-01

    Grain size distribution, porosity, and hydraulic conductivity were determined for 39 sediment samples collected from ephemeral streams (wadis) in western Saudi Arabia. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations commonly used to estimate hydraulic conductivity from grain size analyses. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly with the measured hydraulic conductivity values. Modifications of the empirical equations, including changes to special coefficients and statistical offsets, were made to produce modified equations that considerably improved the hydraulic conductivity estimates from grain size data for wadi sediments. The Chapuis, Hazen, Kozeny, Slichter, Terzaghi, and Barr equations produced the best correlations, but still had relatively high predictive errors. The Chapius equation was modified for wadi sediments by incorporating mud percentage and the standard deviation (in phi units) into a new equation that reduced the predicted hydraulic conductivity error to ±14.1 m/day. The equation is best applied to ephemeral stream samples that have hydraulic conductive values greater than 2 m/day.

  20. Pressurized Thermal Shock, Pts

    International Nuclear Information System (INIS)

    Boyd, C.

    2008-01-01

    Pressurized Thermal Shock (Pts) refers to a condition that challenges the integrity of the reactor pressure vessel. The root cause of this problem is the radiation embrittlement of the reactor vessel. This embrittlement leads to an increase in the reference temperature for nil ductility transition (RTNDT). RTNDT can increase to the point where the reactor vessel material can loose fracture toughness during overcooling events. The analysis of the risk of having a Pts for a specific plant is a multi-disciplinary problem involving probabilistic risk analysis (PRA), thermal-hydraulic analysis, and ultimately a structural and fracture analysis of the vessel wall. The PRA effort involves the postulation of overcooling events and ultimately leads to an integrated risk analysis. The thermal-hydraulic effort involves the difficult task of predicting the system behavior during a postulated overcooling scenario with a special emphasis on predicting the thermal and mechanic loadings on the reactor pressure vessel wall. The structural and fracture analysis of the reactor vessel wall relies on the thermal-hydraulic conditions as boundary conditions. The US experience has indicated that medium and large diameter primary system breaks dominate the risk of Pts along with scenarios that involve a stuck open valve (and associated system cooldown) that recloses resulting in system re-pressurization while the vessel wall is cool.

  1. First-order Probabilistic Analysis of the Effects of Heterogeneity on Pore-water Pressure in a Hillslope

    Science.gov (United States)

    Cai, J.; Yan, E.; Yeh, T. C. J.

    2015-12-01

    Pore-water pressure in a hillslope is a critical control of its stability. The main objective of this paper is to introduce a first-order moment analysis to investigate the pressure head variability within a hypothetical hillslope, induced by steady rainfall infiltration. This approach accounts for the uncertainties and spatial variation of the hydraulic conductivity, and is based on a first-order Taylor approximation of pressure perturbations calculated by a variably saturated, finite element flow model. Using this approach, the effects of variance (σ2lnKs) and spatial structure anisotropy (λh/λv) of natural logarithm of saturated hydraulic conductivity, and normalized vertical infiltration flux (q/ks) on the hillslope pore-water pressure are evaluated. We found that the responses of pressure head variability (σ2p) are quite different between unsaturated region and saturated region divided by the phreatic surface. Above the phreatic surface, a higher variability in pressure head is obtained from a higher σ2lnKs, a higher λh/λv and a smaller q/ks; while below the phreatic surface, a higher σ2lnKs, a lower λh/λv or a larger q/ks would lead to a higher variability in pressure head, and greater range of fluctuation of the phreatic surface within the hillslope. σ2lnKs has greatest impact on σ2p within the slope and λh/λv has smallest impact. All three variables have greater influence on maximum σ2p within the saturated region below the phreatic surface than that within the unsaturated region above the phreatic surface. The results obtained from this study are useful to understand the influence of hydraulic conductivity variations on slope seepage and stability under different slope conditions and material spatial distributions.

  2. Analysis and interpretation of borehole hydraulic tests in deep boreholes: principles, model development, and applications

    International Nuclear Information System (INIS)

    Pickens, J.F.; Grisak, G.E.; Avis, J.D.; Belanger, D.W.

    1987-01-01

    A review of the literature on hydraulic testing and interpretive methods, particularly in low-permeability media, indicates a need for a comprehensive hydraulic testing interpretive capability. Physical limitations on boreholes, such as caving and erosion during continued drilling, as well as the high costs associated with deep-hole rigs and testing equipment, often necessitate testing under nonideal conditions with respect to antecedent pressures and temperatures. In these situations, which are common in the high-level nuclear waste programs throughout the world, the interpretive requirements include the ability to quantitatively account for thermally induced pressure responses and borehole pressure history (resulting in a time-dependent pressure profile around the borehole) as well as equipment compliance effects in low-permeability intervals. A numerical model was developed to provide the capability to handle these antecedent conditions. Sensitivity studies and practical applications are provided to illustrate the importance of thermal effects and antecedent pressure history. It is demonstrated theoretically and with examples from the Swiss (National Genossenschaft fuer die Lagerung radioaktiver Abfaelle) regional hydrogeologic characterization program that pressure changes (expressed as hydraulic head) of the order of tens to hundreds of meters can results from 1 0 to 2 0 C temperature variations during shut-in (packer isolated) tests in low-permeability formations. Misinterpreted formation pressures and hydraulic conductivity can also result from inaccurate antecedent pressure history. Interpretation of representative formation properties and pressures requires that antecedent pressure information and test period temperature data be included as an integral part of the hydraulic test analyses

  3. Charging valve of the full hydraulic braking system

    Directory of Open Access Journals (Sweden)

    Jinshi Chen

    2016-03-01

    Full Text Available It is known that the full hydraulic braking system has excellent braking performance. As the key component of the full hydraulic braking system, the parameters of the accumulator charging valve have a significant effect on the braking performance. In this article, the key parameters of the charging valve are analyzed through the static theoretical and an Advanced Modeling Environment for performing Simulation of engineering systems (AMESim simulation model of the dual-circuit accumulator charging valve is established based on the real structure parameters first. Second, according to the results of the dynamic simulation, the dynamic characteristics of the charging pressure, the flow rate, and the frequency of the charging valve are studied. The key parameters affecting the serial production are proposed and some technical advices for improving the performance of the full hydraulic system are provided. Finally, the theoretical analysis is validated by the simulation results. The comparison between the simulation results and the experimental results indicates that the simulated AMESim model of the charging valve is accurate and credible with the error rate inside 0.5% compared with the experimental result. Hence, the performance of the charging valve meets the request of the full hydraulic braking system exactly.

  4. Impact of ductility on hydraulic fracturing in shales

    Science.gov (United States)

    MacMinn, Chris; Auton, Lucy

    2016-04-01

    Hydraulic fracturing is a method for extracting natural gas and oil from low-permeability rocks such as shale via the high-pressure injection of fluid into the bulk of the rock. The goal is to initiate and propagate fractures that will provide hydraulic access deeper into the reservoir, enabling gas or oil to be collected from a larger region of the rock. Fracture is the tensile failure of a brittle material upon reaching a threshold tensile stress, but some shales have a high clay content and may yield plastically before fracturing. Plastic deformation is the shear failure of a ductile material, during which stress relaxes through irreversible rearrangements of the particles of the material. Here, we investigate the impact of the ductility of shales on hydraulic fracturing. We first consider a simple, axisymmetric model for radially outward fluid injection from a wellbore into a ductile porous rock. We use this model to show that plastic deformation greatly reduces the maximum tensile stress, and that this maximum stress does not always occur at the wellbore. We then complement these results with laboratory experiments in an analogue system, and with numerical simulations based on the discrete element method (DEM), both of which suggest that ductile failure can indeed dramatically change the resulting deformation pattern. These results imply that hydraulic fracturing may fail in ductile rocks, or that the required injection rate for fracking may be much larger than the rate predicted from models that assume purely elastic mechanical behavior.

  5. The study of pressure fluctuations in the pressure line of the pump and of the efficiency of the vibration absorbers

    Directory of Open Access Journals (Sweden)

    O.V. Korolyov

    2016-12-01

    Full Text Available The article presents the results of experimental studies of pressure fluctuations in the pipes of piston pumps. The relevance of these studies is due to the need to reduce the pressure fluctuations that create a positive displacement pumps, due to their negative impact not only on the reliability of the pump, but the accuracy of flow measurement and pressure of the medium supplied to such pumps. Aim: The aim of this study was to investigate the hydraulic characteristics of pulsating flows in pressure lines piston pumps of liquefied gas, as well as the study of the effectiveness of the dampers of pressure pulsations and conformity of their parameters to the calculation. Materials and Methods: As a drive used the piston pumps − single-line and trilinear. In the tests recorded pressure fluctuations in the pressure line. For this purpose the low-inertia pressure sensors 15.0 MPa working complete with strain test station, which allows registering the pressure fluctuations at frequencies up to 10 kHz. Strain test station output signal fed to the input of the oscilloscope operating in memory mode. In all tests the pressure sensor is mounted at three points - after the piston group on the pressure line before the damping device and after it. In the experiment, three different damper was used - two new, designed by the author's method and one regular damper, which are equipped with serial piston pumps. Dampers installed vertically, the flow entering to the lower cap, and an output through the side surface. Results: The experimental results confirmed the general position of the greater efficiency of complex composite filters and the correctness of chosen method of their calculation, proposed earlier by the authors. In particular, the actual level of weakening of pressure fluctuations on developed damper with a high degree coincided with the calculated results.

  6. Hydrology and Hydraulic Properties of a Bedded Evaporite Formation

    International Nuclear Information System (INIS)

    BEAUHEIM, RICHARD L.; ROBERTS, RANDALL M.

    2000-01-01

    The Permian Salado Formation in the Delaware Basin of New Mexico is an extensively studied evaporite deposit because it is the host formation for the Waste Isolation Pilot Plant, a repository for transuranic wastes. Geologic and hydrologic studies of the Salado conducted since the mid-1970's have led to the development of a conceptual model of the hydrogeology of the formation that involves far-field permeability in anhydrite layers and at least some impure halite layers. Pure halite layers and some impure halite layers may not possess an interconnected pore network adequate to provide permeability. Pore pressures are probably very close to lithostatic pressure. In the near field around an excavation, dilation, creep, and shear have created and/or enhanced permeability and decreased pore pressure. Whether flow occurs in the far field under natural gradients or only after some threshold gradient is reached is unknown. If far-field flow does occur, mean pore velocities are probably on the order of a meter per hundreds of thousands to tens of millions of years. Flow dimensions inferred from most hydraulic-test responses are subradial, which is believed to reflect channeling of flow through fracture networks, or portions of fractures, that occupy a diminishing proportion of the radially available space, or through percolation networks that are not ''saturated'' (fully interconnected). This is probably related to the directional nature of the permeability created or enhanced by excavation effects. Inferred values of permeability cannot be separated from their associated flow dimensions. Therefore, numerical models of flow and transport should include heterogeneity that is structured to provide the same flow dimensions as are observed in hydraulic tests. Modeling of the Salado Formation around the WIPP repository should also include coupling between hydraulic properties and the evolving stress field because hydraulic properties change as the stress field changes

  7. Hydraulic design development of Xiluodu Francis turbine

    International Nuclear Information System (INIS)

    Wang, Y L; Li, G Y; Shi, Q H; Wang, Z N

    2012-01-01

    Hydraulic optimization design with CFD (Computational Fluid Dynamics) method, hydraulic optimization measures and model test results in the hydraulic development of Xiluodu hydropower station by DFEM (Dongfang Electric Machinery) of DEC (Dongfang Electric Corporation) of China were analyzed in this paper. The hydraulic development conditions of turbine, selection of design parameter, comparison of geometric parameters and optimization measure of turbine flow components were expatiated. And the measures of improving turbine hydraulic performance and the results of model turbine acceptance experiment were discussed in details.

  8. Simulations of hydraulic fracturing and leakage in sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Lothe, Ane Elisabeth

    2004-01-01

    Hydraulic fracturing and leakage of water through the caprock is described from sedimentary basin over geological time scale. Abnormal pressure accumulations reduce the effective stresses in the underground and trigger the initiation of hydraulic fractures. The major faults in the basin define these pressure compartments. In this Thesis, basin simulations of hydraulic fracturing and leakage have been carried out. A simulator (Pressim) is used to calculate pressure generation and dissipitation between the compartments. The flux between the compartments and not the flow within the compartments is modelled. The Griffith-Coulomb failure criterion determines initial failure at the top structures of overpressured compartments, whereas the frictional sliding criterion is used for reactivation along the same fractures. The minimum horizontal stress is determined from different formulas, and an empirical one seems to give good results compared to measured pressures and minimum horizontal stresses. Simulations have been carried out on two datasets; one covering the Halten Terrace area and one the Tune Field area in the northern North Sea. The timing of hydraulic fracturing and amount of leakage has been quantified in the studies from the Halten Terrace area. This is mainly controlled by the lateral fluid flow and the permeability of the major faults in the basin. Low fault permeability gives early failure, while high fault permeabilities results in no or late hydraulic fracturing and leakage from overpressured parts of the basin. In addition to varying the transmissibility of all faults in a basin, the transmissibility across individual faults can be varied. Increasing the transmissibility across faults is of major importance in overpressured to intermediately pressured areas. However, to obtain change in the flow, a certain pressure difference has to be the situation between the different compartments. The coefficient of internal friction and the coefficient of frictional

  9. Experimental simulation study on hydraulic behavior of the main heat exchanger of Daqing 200 MW nuclear heating reactor

    International Nuclear Information System (INIS)

    Jiang Shengyao; Zhang Youjie; Jia Haijun; Bo Jinhai; Hong Liuming; Bo Hanliang; Liu Zhiyong

    1997-07-01

    The hydraulic behavior of the main heat exchanger of Daqing 200 MW nuclear heating reactor is studied through a 1:2.33 test model. The design and other feature of the test model is described. The experimental results show that the flow resistance coefficient of the heat exchanger becomes self-simulation when Reynolds number is greater than 5000. The value of flow resistance coefficient at self-simulation condition and the distribution of pressure drop in the heat exchanger are given through experiment. The option design to reduce flow resistance is proposed. The designed and experimental value for the flow resistance coefficient are in good agreement. The variation of system parameters during flow excursion was described. The experimental results are of great significant for the final design of the main heat exchanger of Daqing 200 MW nuclear heating reactor. (2 refs., 5 figs., 1 tab.)

  10. Scaling Analysis of the Single-Phase Natural Circulation: the Hydraulic Similarity

    International Nuclear Information System (INIS)

    Yu, Xin-Guo; Choi, Ki-Yong

    2015-01-01

    These passive safety systems all rely on the natural circulation to cool down the reactor cores during an accident. Thus, a robust and accurate scaling methodology must be developed and employed to both assist in the design of a scaled-down test facility and guide the tests in order to mimic the natural circulation flow of its prototype. The natural circulation system generally consists of a heat source, the connecting pipes and several heat sinks. Although many applauding scaling methodologies have been proposed during last several decades, few works have been dedicated to systematically analyze and exactly preserve the hydraulic similarity. In the present study, the hydraulic similarity analyses are performed at both system and local level. By this mean, the scaling criteria for the exact hydraulic similarity in a full-pressure model have been sought. In other words, not only the system-level but also the local-level hydraulic similarities are pursued. As the hydraulic characteristics of a fluid system is governed by the momentum equation, the scaling analysis starts with it. A dimensionless integral loop momentum equation is derived to obtain the dimensionless numbers. In the dimensionless momentum equation, two dimensionless numbers, the dimensionless flow resistance number and the dimensionless gravitational force number, are identified along with a unique hydraulic time scale, characterizing the system hydraulic response. A full-height full-pressure model is also made to see which model among the full-height model and reduced-height model can preserve the hydraulic behavior of the prototype. From the dimensionless integral momentum equation, a unique hydraulic time scale, which characterizes the hydraulic response of a single-phase natural circulation system, is identified along with two dimensionless parameters: the dimensionless flow resistance number and the dimensionless gravitational force number. By satisfying the equality of both dimensionless numbers

  11. Scaling Analysis of the Single-Phase Natural Circulation: the Hydraulic Similarity

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xin-Guo; Choi, Ki-Yong [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    These passive safety systems all rely on the natural circulation to cool down the reactor cores during an accident. Thus, a robust and accurate scaling methodology must be developed and employed to both assist in the design of a scaled-down test facility and guide the tests in order to mimic the natural circulation flow of its prototype. The natural circulation system generally consists of a heat source, the connecting pipes and several heat sinks. Although many applauding scaling methodologies have been proposed during last several decades, few works have been dedicated to systematically analyze and exactly preserve the hydraulic similarity. In the present study, the hydraulic similarity analyses are performed at both system and local level. By this mean, the scaling criteria for the exact hydraulic similarity in a full-pressure model have been sought. In other words, not only the system-level but also the local-level hydraulic similarities are pursued. As the hydraulic characteristics of a fluid system is governed by the momentum equation, the scaling analysis starts with it. A dimensionless integral loop momentum equation is derived to obtain the dimensionless numbers. In the dimensionless momentum equation, two dimensionless numbers, the dimensionless flow resistance number and the dimensionless gravitational force number, are identified along with a unique hydraulic time scale, characterizing the system hydraulic response. A full-height full-pressure model is also made to see which model among the full-height model and reduced-height model can preserve the hydraulic behavior of the prototype. From the dimensionless integral momentum equation, a unique hydraulic time scale, which characterizes the hydraulic response of a single-phase natural circulation system, is identified along with two dimensionless parameters: the dimensionless flow resistance number and the dimensionless gravitational force number. By satisfying the equality of both dimensionless numbers

  12. GCFR thermal-hydraulic experiments

    International Nuclear Information System (INIS)

    Schlueter, G.; Baxi, C.B.; Dalle Donne, M.; Gat, U.; Fenech, H.; Hanson, D.; Hudina, M.

    1980-01-01

    The thermal-hydraulic experimental studies performed and planned for the Gas-Cooled Fast Reactor (GCFR) core assemblies are described. The experiments consist of basic studies performed to obtain correlations, and bundle experiments which provide input for code validation and design verification. These studies have been performed and are planned at European laboratories, US national laboratories, Universities in the US, and at General Atomic Company

  13. Hysteresis phenomena in hydraulic measurement

    International Nuclear Information System (INIS)

    Ran, H J; Farhat, M; Luo, X W; Chen, Y L; Xu, H Y

    2012-01-01

    Hysteresis phenomena demonstrate the lag between the generation and the removal of some physical phenomena. This paper studies the hysteresis phenomena of the head-drop in a scaled model pump turbine using experiment test and CFD methods. These lag is induced by complicated flow patterns, which influenced the reliability of rotating machine. Keeping the same measurement procedure is concluded for the hydraulic machine measurement.

  14. Detection of cavitation in hydraulic turbines

    Science.gov (United States)

    Escaler, Xavier; Egusquiza, Eduard; Farhat, Mohamed; Avellan, François; Coussirat, Miguel

    2006-05-01

    An experimental investigation has been carried out in order to evaluate the detection of cavitation in actual hydraulic turbines. The methodology is based on the analysis of structural vibrations, acoustic emissions and hydrodynamic pressures measured in the machine. The proposed techniques have been checked in real prototypes suffering from different types of cavitation. In particular, one Kaplan, two Francis and one Pump-Turbine have been investigated in the field. Additionally, one Francis located in a laboratory has also been tested. First, a brief description of the general features of cavitation phenomenon is given as well as of the main types of cavitation occurring in hydraulic turbines. The work presented here is focused on the most important ones which are the leading edge cavitation due to its erosive power, the bubble cavitation because it affects the machine performance and the draft tube swirl that limits the operation stability. Cavitation detection is based on the previous understanding of the cavity dynamics and its location inside the machine. This knowledge has been gained from flow visualisations and measurements in laboratory devices such as a high-speed cavitation tunnel and a reduced scale turbine test rig. The main techniques are the study of the high frequency spectral content of the signals and of their amplitude demodulation for a given frequency band. Moreover, low frequency spectral content can also be used in certain cases. The results obtained for the various types of cavitation found in the selected machines are presented and discussed in detail in the paper. Conclusions are drawn about the best sensor, measuring location, signal processing and analysis for each type of cavitation, which serve to validate and to improve the detection techniques.

  15. Gas Test Loop Booster Fuel Hydraulic Testing

    International Nuclear Information System (INIS)

    Gas Test Loop Hydraulic Testing Staff

    2006-01-01

    The Gas Test Loop (GTL) project is for the design of an adaptation to the Advanced Test Reactor (ATR) to create a fast-flux test space where fuels and materials for advanced reactor concepts can undergo irradiation testing. Incident to that design, it was found necessary to make use of special booster fuel to enhance the neutron flux in the reactor lobe in which the Gas Test Loop will be installed. Because the booster fuel is of a different composition and configuration from standard ATR fuel, it is necessary to qualify the booster fuel for use in the ATR. Part of that qualification is the determination that required thermal hydraulic criteria will be met under routine operation and under selected accident scenarios. The Hydraulic Testing task in the GTL project facilitates that determination by measuring flow coefficients (pressure drops) over various regions of the booster fuel over a range of primary coolant flow rates. A high-fidelity model of the NW lobe of the ATR with associated flow baffle, in-pile-tube, and below-core flow channels was designed, constructed and located in the Idaho State University Thermal Fluids Laboratory. A circulation loop was designed and constructed by the university to provide reactor-relevant water flow rates to the test system. Models of the four booster fuel elements required for GTL operation were fabricated from aluminum (no uranium or means of heating) and placed in the flow channel. One of these was instrumented with Pitot tubes to measure flow velocities in the channels between the three booster fuel plates and between the innermost and outermost plates and the side walls of the flow annulus. Flow coefficients in the range of 4 to 6.5 were determined from the measurements made for the upper and middle parts of the booster fuel elements. The flow coefficient for the lower end of the booster fuel and the sub-core flow channel was lower at 2.3

  16. Gas Test Loop Booster Fuel Hydraulic Testing

    Energy Technology Data Exchange (ETDEWEB)

    Gas Test Loop Hydraulic Testing Staff

    2006-09-01

    The Gas Test Loop (GTL) project is for the design of an adaptation to the Advanced Test Reactor (ATR) to create a fast-flux test space where fuels and materials for advanced reactor concepts can undergo irradiation testing. Incident to that design, it was found necessary to make use of special booster fuel to enhance the neutron flux in the reactor lobe in which the Gas Test Loop will be installed. Because the booster fuel is of a different composition and configuration from standard ATR fuel, it is necessary to qualify the booster fuel for use in the ATR. Part of that qualification is the determination that required thermal hydraulic criteria will be met under routine operation and under selected accident scenarios. The Hydraulic Testing task in the GTL project facilitates that determination by measuring flow coefficients (pressure drops) over various regions of the booster fuel over a range of primary coolant flow rates. A high-fidelity model of the NW lobe of the ATR with associated flow baffle, in-pile-tube, and below-core flow channels was designed, constructed and located in the Idaho State University Thermal Fluids Laboratory. A circulation loop was designed and constructed by the university to provide reactor-relevant water flow rates to the test system. Models of the four booster fuel elements required for GTL operation were fabricated from aluminum (no uranium or means of heating) and placed in the flow channel. One of these was instrumented with Pitot tubes to measure flow velocities in the channels between the three booster fuel plates and between the innermost and outermost plates and the side walls of the flow annulus. Flow coefficients in the range of 4 to 6.5 were determined from the measurements made for the upper and middle parts of the booster fuel elements. The flow coefficient for the lower end of the booster fuel and the sub-core flow channel was lower at 2.3.

  17. Nonlinear Non-convex Optimization of Hydraulic Networks

    DEFF Research Database (Denmark)

    Tahavori, Maryamsadat; Kallesøe, Carsten; Leth, John-Josef

    2013-01-01

    Pressure management in water supply systems is an effective way to reduce the leakage in a system. In this paper, the pressure management and the reduction of power consumption of a water supply system is formulated as an optimization problem. The problem is to minimize the power consumption in p....... They can be used for a general hydraulic networks to optimize the leakage and energy consumption and to satisfy the demands at the end-users. The results in this paper show that the power consumption of the pumps is reduced.......Pressure management in water supply systems is an effective way to reduce the leakage in a system. In this paper, the pressure management and the reduction of power consumption of a water supply system is formulated as an optimization problem. The problem is to minimize the power consumption...

  18. Computing in Hydraulic Engineering Education

    Science.gov (United States)

    Duan, J. G.

    2011-12-01

    Civil engineers, pioneers of our civilization, are rarely perceived as leaders and innovators in modern society because of retardations in technology innovation. This crisis has resulted in the decline of the prestige of civil engineering profession, reduction of federal funding on deteriorating infrastructures, and problems with attracting the most talented high-school students. Infusion of cutting-edge computer technology and stimulating creativity and innovation therefore are the critical challenge to civil engineering education. To better prepare our graduates to innovate, this paper discussed the adaption of problem-based collaborative learning technique and integration of civil engineering computing into a traditional civil engineering curriculum. Three interconnected courses: Open Channel Flow, Computational Hydraulics, and Sedimentation Engineering, were developed with emphasis on computational simulations. In Open Channel flow, the focuses are principles of free surface flow and the application of computational models. This prepares students to the 2nd course, Computational Hydraulics, that introduce the fundamental principles of computational hydraulics, including finite difference and finite element methods. This course complements the Open Channel Flow class to provide students with in-depth understandings of computational methods. The 3rd course, Sedimentation Engineering, covers the fundamentals of sediment transport and river engineering, so students can apply the knowledge and programming skills gained from previous courses to develop computational models for simulating sediment transport. These courses effectively equipped students with important skills and knowledge to complete thesis and dissertation research.

  19. Numerical and computational aspects of the coupled three-dimensional core/ plant simulations: organization for economic cooperation and development/ U.S. nuclear regulatory commission pressurized water reactor main-steam-line-break benchmark-II. 5. TMI-1 Benchmark Performed by Different Coupled Three-Dimensional Neutronics Thermal- Hydraulic Codes

    International Nuclear Information System (INIS)

    D'Auria, F.; Galassi, G.M.; Spadoni, A.; Gago, J.L.; Grgic, D.

    2001-01-01

    the benchmark are discussed in documents listed in Ref. 1. Items like nodalization development and qualification at the 'steady state' and at the 'on-transient' level are evaluated. Dependency of calculation outputs upon the interpretation of boundary and initial conditions is discussed together with the comparison of the obtained results with those obtained by other participants in the benchmark. The influence of the following items upon the predicted results are considered: 1. modeling of the break; 2. position where the high-pressure injection system pressure needed for flow rate control is measured; 3. modeling of the NPP system downstream of the main isolation valves; 4. modeling of the feedwater line; 5. modeling of the upper-head-upper-plenum bypass; 6. influence of the steam generator mass inventory; 7. failure of the scram system (occurrence of an anticipated transient without scram). The capability of the control rods to recover the accident has been demonstrated in all the cases as well as the capability of all the codes to predict the time evolution of the assigned transient. The stuck-withdrawn control rod caused some recriticality or RTP whose magnitude is largely affected by boundary and initial conditions. Thermal-hydraulic modeling of the steam generators and of the thermal coupling between the primary and secondary side had an important role in predicting the transient evolution. In particular, one can affirm that interfacial drag modeling affects the core power and time sequence of events, should an MSLB occur. The comparison among the results in terms of core power and distributions obtained by adopting the same thermal-hydraulic nodalization and the three 'coupled' 3-D neutronics thermal-hydraulics code versions (as mentioned earlier) showed the importance of (a) (user) selection of the thermal-hydraulic code version and (b) (user) selection of coupling options. In quantitative terms, the influence of the preceding two topics is estimated to be of

  20. Environmental and management influences on temporal variability of near saturated soil hydraulic properties.

    Science.gov (United States)

    Bodner, G; Scholl, P; Loiskandl, W; Kaul, H-P

    2013-08-01

    Structural porosity is a decisive property for soil productivity and soil environmental functions. Hydraulic properties in the structural range vary over time in response to management and environmental influences. Although this is widely recognized, there are few field studies that determine dominant driving forces underlying hydraulic property dynamics. During a three year field experiment we measured temporal variability of soil hydraulic properties by tension infiltrometry. Soil properties were characterized by hydraulic conductivity, effective macroporosity and Kosugi's lognormal pore size distribution model. Management related influences comprised three soil cover treatment (mustard and rye vs. fallow) and an initial mechanical soil disturbance with a rotary harrow. Environmental driving forces were derived from meteorological and soil moisture data. Soil hydraulic parameters varied over time by around one order of magnitude. The coefficient of variation of soil hydraulic conductivity K(h) decreased from 69.5% at saturation to 42.1% in the more unsaturated range (- 10 cm pressure head). A slight increase in the Kosugi parameter showing pore heterogeneity was observed under the rye cover crop, reflecting an enhanced structural porosity. The other hydraulic parameters were not significantly influenced by the soil cover treatments. Seedbed preparation with a rotary harrow resulted in a fourfold increase in macroporosity and hydraulic conductivity next to saturation, and homogenized the pore radius distribution. Re-consolidation after mechanical loosening lasted over 18 months until the soil returned to its initial state. The post-tillage trend of soil settlement could be approximated by an exponential decay function. Among environmental factors, wetting-drying cycles were identified as dominant driving force explaining short term hydraulic property changes within the season (r 2  = 0.43 to 0.59). Our results suggested that beside considering average

  1. Shallow Aquifer Vulnerability From Subsurface Fluid Injection at a Proposed Shale Gas Hydraulic Fracturing Site

    Science.gov (United States)

    Wilson, M. P.; Worrall, F.; Davies, R. J.; Hart, A.

    2017-11-01

    Groundwater flow resulting from a proposed hydraulic fracturing (fracking) operation was numerically modeled using 91 scenarios. Scenarios were chosen to be a combination of hydrogeological factors that a priori would control the long-term migration of fracking fluids to the shallow subsurface. These factors were induced fracture extent, cross-basin groundwater flow, deep low hydraulic conductivity strata, deep high hydraulic conductivity strata, fault hydraulic conductivity, and overpressure. The study considered the Bowland Basin, northwest England, with fracking of the Bowland Shale at ˜2,000 m depth and the shallow aquifer being the Sherwood Sandstone at ˜300-500 m depth. Of the 91 scenarios, 73 scenarios resulted in tracked particles not reaching the shallow aquifer within 10,000 years and 18 resulted in travel times less than 10,000 years. Four factors proved to have a statistically significant impact on reducing travel time to the aquifer: increased induced fracture extent, absence of deep high hydraulic conductivity strata, relatively low fault hydraulic conductivity, and magnitude of overpressure. Modeling suggests that high hydraulic conductivity formations can be more effective barriers to vertical flow than low hydraulic conductivity formations. Furthermore, low hydraulic conductivity faults can result in subsurface pressure compartmentalization, reducing horizontal groundwater flow, and encouraging vertical fluid migration. The modeled worst-case scenario, using unlikely geology and induced fracture lengths, maximum values for strata hydraulic conductivity and with conservative tracer behavior had a particle travel time of 130 years to the base of the shallow aquifer. This study has identified hydrogeological factors which lead to aquifer vulnerability from shale exploitation.

  2. Dynamic Characteristics of Communication Lines with Distributed Parameters to Control the Throttle-controlled Hydraulic Actuators

    Directory of Open Access Journals (Sweden)

    D. N. Popov

    2015-01-01

    Full Text Available The article considers a mathematical model of the hydraulic line for remote control of electro-hydraulic servo drive (EHSD with throttle control. This type of hydraulic lines is designed as a backup to replace the electrical connections, which are used to control EHSD being remote from the site with devices located to form the control signals of any object. A disadvantage of electric connections is that they are sensitive to magnetic fields and thereby do not provide the required reliability of the remote control. Hydraulic lines have no this disadvantage and therefore are used in aircraft and other industrial systems. However, dynamic characteristics of hydraulic systems still have been investigated insufficiently in the case of transmitting control signals at a distance at which the signal may be distorted when emerging the wave processes.The article results of mathematical simulation, which are verified through physical experimentation, largely eliminate the shortcomings of said information.The mathematical model described in the paper is based on the theory of unsteady pressure compressible fluids. In the model there are formulas that provide calculation of frequency characteristics of the hydraulic lines under hydraulic oscillations of the laminar flow parameters of viscous fluid.A real mock-up of the system under consideration and an experimental ad hoc unit are used to verify the results of mathematically simulated hydraulic systems.Calculated logarithmic amplitude and phase frequency characteristics compared with those obtained experimentally prove, under certain conditions, the proposed theoretical method of calculation. These conditions have to ensure compliance with initial parameters of fluid defined under stationary conditions. The applied theory takes into consideration a non-stationary hydraulic resistance of the line when calculating frequency characteristics.The scientific novelty in the article material is presented in

  3. Numerical study of the thermo-hydraulic behavior for the Candu type fuel channel

    International Nuclear Information System (INIS)

    Lazaro, Pavel Gabriel; Balas Ghizdeanu, Elena Nineta

    2008-01-01

    Candu type reactors use fuel channel in a horizontal lattice. The fuel bundles are positioned in two Zircaloy tubes: the pressure tube surrounded by calandria tube. Inside the pressure tube the coolant heavy water flows. The coolant reaches high temperatures and pressures. Due to irregular neutron spatial distribution, the fuel channel stress differs from one channel to other. In one improbable event of severe accident, the fuel channel behaves differently according to its normal function history. Over the years, there have been many research projects trying to analyze thermal hydraulic performance of the design and to add some operational improvements in order to achieve an efficient thermal hydraulic distribution. This paper discusses the thermo hydraulic behavior (influence of the temperature and velocity distribution) of the most solicited channel, simulated with Fluent 6.X. Code. Moreover it will be commented the results obtained using different models and mesh applied. (authors)

  4. Estimating biozone hydraulic conductivity in wastewater soil-infiltration systems using inverse numerical modeling.

    Science.gov (United States)

    Bumgarner, Johnathan R; McCray, John E

    2007-06-01

    During operation of an onsite wastewater treatment system, a low-permeability biozone develops at the infiltrative surface (IS) during application of wastewater to soil. Inverse numerical-model simulations were used to estimate the biozone saturated hydraulic conductivity (K(biozone)) under variably saturated conditions for 29 wastewater infiltration test cells installed in a sandy loam field soil. Test cells employed two loading rates (4 and 8cm/day) and 3 IS designs: open chamber, gravel, and synthetic bundles. The ratio of K(biozone) to the saturated hydraulic conductivity of the natural soil (K(s)) was used to quantify the reductions in the IS hydraulic conductivity. A smaller value of K(biozone)/K(s,) reflects a greater reduction in hydraulic conductivity. The IS hydraulic conductivity was reduced by 1-3 orders of magnitude. The reduction in IS hydraulic conductivity was primarily influenced by wastewater loading rate and IS type and not by the K(s) of the native soil. The higher loading rate yielded greater reductions in IS hydraulic conductivity than the lower loading rate for bundle and gravel cells, but the difference was not statistically significant for chamber cells. Bundle and gravel cells exhibited a greater reduction in IS hydraulic conductivity than chamber cells at the higher loading rates, while the difference between gravel and bundle systems was not statistically significant. At the lower rate, bundle cells exhibited generally lower K(biozone)/K(s) values, but not at a statistically significant level, while gravel and chamber cells were statistically similar. Gravel cells exhibited the greatest variability in measured values, which may complicate design efforts based on K(biozone) evaluations for these systems. These results suggest that chamber systems may provide for a more robust design, particularly for high or variable wastewater infiltration rates.

  5. Thermal-Hydraulic Performance of Scrubbing Nozzle Used for CFVS

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Chul; Lee, Doo Yong; Jung, Woo Young; Lee, Jong Chan; Kim, Gyu Tae [FNC TECH, Yongin (Korea, Republic of)

    2016-05-15

    A Containment Filtered Venting System (CFVS) is the most interested device to mitigate a threat against containment integrity under the severe accident of nuclear power plant by venting with the filtration of the fission products. FNC technology and partners have been developed the self-priming scrubbing nozzle used for the CFVS which is based on the venturi effect. The thermal-hydraulic performances such as passive scrubbing water suction as well as pressure drop across the nozzle have been tested under various thermal-hydraulic conditions. The two types of test section have been built for testing the thermal-hydraulic performance of the self-priming scrubbing nozzle. Through the visualization loop, the liquid suction performance through the slit, pressure drop across the nozzle are measured. The passive water suction flow through the suction slit at the throat is important parameter to define the scrubbing performance of the self-priming scrubbing nozzle. The water suction flow is increased with the increase of the overhead water level at the same inlet gas flow. It is not so much changed with the change of inlet gas flow at the overhead water level.

  6. Design and analysis of hydraulic ram water pumping system

    Science.gov (United States)

    Hussin, N. S. M.; Gamil, S. A.; Amin, N. A. M.; Safar, M. J. A.; Majid, M. S. A.; Kazim, M. N. F. M.; Nasir, N. F. M.

    2017-10-01

    The current pumping system (DC water pump) for agriculture is powered by household electricity, therefore, the cost of electricity will be increased due to the higher electricity consumption. In addition, the water needs to be supplied at different height of trees and different places that are far from the water source. The existing DC water pump can pump the water to 1.5 m height but it cost money for electrical source. The hydraulic ram is a mechanical water pump that suitable used for agriculture purpose. It can be a good substitute for DC water pump in agriculture use. The hydraulic ram water pumping system has ability to pump water using gravitational energy or the kinetic energy through flowing source of water. This project aims to analyze and develop the water ram pump in order to meet the desired delivery head up to 3 meter height with less operation cost. The hydraulic ram is designed using CATIA software. Simulation work has been done using ANSYS CFX software to validate the working concept. There are three design were tested in the experiment study. The best design reached target head of 3 m with 15% efficiency and flow rate of 11.82l/min. The results from this study show that the less diameter of pressure chamber and higher supply head will create higher pressure.

  7. Design of a hydraulic loop for characterization of nuclear fuels for the Rech-1

    International Nuclear Information System (INIS)

    Munoz Reveco, David Hernan

    2016-01-01

    The Chilean Nuclear Energy Commission (CCHEN), in particular the Fuels Elements Plant (PEC), wants to increase its capacity of design of nuclear fuel elements (ECN). The International Atomic Energy Agency (IAEA) stipulates that in order to develop new ECN designs must be met with neutron, structural, thermal and hydraulics. The CCHEN in the first instance, wishes to implement the hydraulic tests with a test bench which is called 'Hydraulic Loop (LH)'. The general objective of the project is to design a LH at the level of detailed engineering, with the purpose to characterize ECN hydraulically of the RECH-1 reactor. The specific objectives are: (i) Carry out the conceptual design and control philosophy applicable to the LH, ii) Develop the design LH baseline including layout, equipment, instrumentation and assembly; and iii) Carry out the detailed design for LH construction and assembly including technical specifications for the acquisition, construction and assembly of LH, and estimated investments to materialize the project. To carry out the conceptual design of the LH proceed to review piping projects provided by specialists, fluid pressure drop analysis is carried out in pipelines and papers are reviewed on existing LHs (Petten and IPEN). The basic design is developed by setting the conditions system, taking as a design criterion the operating the RECH-2 reactor. For the design of the test zone, the ASME code VIII division 1 section 13-7. The pond develops according to the capacity of fluid contained in the system. The pump is selected by system losses, overestimating the load of the pump. In addition, the characteristic curves of the pump are compared with the curve feature of the system. Detail planes are generated with Autodesk Inventor software Professional 2014-student version. The instrumentation selection is carried out with the advice of a company dedicated to the measurement and control of industrial activities (VETO). The main results of the project

  8. Étude des distributions de contraintes autour d'un puits pétrolier. Application au calcul des pressions d'initiation de fracturation hydraulique Research on Stress Distribution Around an Oil Or Gas Well. Application to Calculating Pressures for Initiating Hydraulic Fracturing

    Directory of Open Access Journals (Sweden)

    Skoczylas F.

    2006-11-01

    Full Text Available Des méthodes de résolution analytiques et numériques ont été proposées, pour déterminer les distributions de contraintes autour de forages pétroliers dans le cas de matériaux peu résistants. Le calcul de ces distributions aboutit à la détermination des pressions de fracturation. Le critère de plasticité de Mohr-Coulomb a été choisi pour la résolution analytique. Cette étude permet d'établir trois schémas types de distribution de contraintes, au moment de la fracturation, pour un régime permanent d'écoulement. La géométrie axisymétrique du modèle a permis d'utiliser une méthode numérique par schéma aux différences finies. La loi de comportement du matériau est déduite du critère de plasticité de Drucker. Cette résolution permet le chargement incrémental en pression dans le forage et de simuler une injection rapide par un couplage simplifié fluide-squelette. Le modèle élastoplastique à deux surfaces de charge de Lade-Shao a finalement été retenu pour décrire l'écrouissage du matériau. La comparaison des résultats des différentes méthodes de calcul s'effectue sur la base de l'influence respective du coefficient de poussée au repos Ko, du coefficient de Poisson et de la résistance à la compression, Co, du matériau. Analytical and numerical methods are proposed, in order to determine stresses distribution around borehole for axisymetric problems in the case of low strengh materials. Calculation of these distributions leads to the determination of hydraulic fracture-pressure. Analytical solutions were found in the case of Mohr-Coulomb criterion and steady flow. These solutions leads to three typical stresses distributions when hydraulic fracture takes place. Because problem's axisymetry, the finite difference method was used. The constitutive law was deduced using Drücker plasticity criterion with an associated flow rule for elastic perfectly plastic behaviour. Such a numerical method can take into

  9. Solid-phase extraction combined with high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry analysis of pesticides in water: method performance and application in a reconnaissance survey of residues in drinking water in Greater Cairo, Egypt.

    Science.gov (United States)

    Potter, Thomas L; Mohamed, Mahmoud A; Ali, Hannah

    2007-01-24

    Monitoring of water resources for pesticide residues is often needed to ensure that pesticide use does not adversely impact the quality of public water supplies or the environment. In many rural areas and throughout much of the developing world, monitoring is often constrained by lack of testing facilities; thus, collection of samples and shipment to centralized laboratories for analysis is required. The portability, ease of use, and potential to enhance analyte stability make solid-phase extraction (SPE) an attractive technique for handling water samples prior to their shipment. We describe performance of an SPE method targeting a structurally diverse mixture of 25 current-use pesticides and two common degradates in samples of raw and filtered drinking water collected in Greater Cairo, Egypt. SPE was completed in a field laboratory in Egypt, and cartridges were shipped to the United States for elution and high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry analysis. Quantitative and reproducible recovery of 23 of 27 compounds (average = 96%; percent relative standard deviation = 21%) from matrix spikes (1 microg L-1 per component) prepared in the field and from deionized water fortified similarly in the analytical laboratory was obtained. Concurrent analysis of unspiked samples identified four parent compounds and one degradate in drinking water samples. No significant differences were observed between raw and filtered samples. Residue levels in all cases were below drinking water and "harm to aquatic-life" thresholds, indicating that human and ecological risks of pesticide contamination were relatively small; however, the study was limited in scale and scope. Further monitoring is needed to define spatial and temporal variation in residue concentrations. The study has demonstrated the feasibility of performing studies of this type using SPE to extract and preserve samples in the field. The approach should be broadly

  10. Calculation of dynamic hydraulic forces in nuclear plant piping systems

    International Nuclear Information System (INIS)

    Choi, D.K.

    1982-01-01

    A computer code was developed as one of the tools needed for analysis of piping dynamic loading on nuclear power plant high energy piping systems, including reactor safety and relief value upstream and discharge piping systems. The code calculates the transient hydraulic data and dynamic forces within the one-dimensional system, caused by a pipe rupture or sudden value motion, using a fixed space and varying time grid-method of characteristics. Subcooled, superheated, homogeneous two-phase and transition flow regimes are considered. A non-equilibrium effect is also considered in computing the fluid specific volume and fluid local sonic velocity in the two-phase mixture. Various hydraulic components such as a spring loaded or power operated value, enlarger, orifice, pressurized tank, multiple pipe junction (tee), etc. are considered as boundary conditions. Comparisons of calculated results with available experimental data shows a good agreement. (Author)

  11. Tracking control of the hydraulically actuated flexible manipulator

    International Nuclear Information System (INIS)

    Kwon, D.S.; Babcock, S.M.; Burks, B.L.; Kress, R.L.

    1995-01-01

    The remediation of single-shell radioactive waste storage tanks is one of the urgent tasks of the Department of Energy that challenge state-of-the-art equipment and methods. The use of long-reach manipulators is being seriously considered for this remediation task. Because high payload capacity and high length-to-cross-section ratio requirements, these long-reach manipulator systems are expected to use hydraulic actuators and to exhibit significant structural flexibility. The controller has been designed to compensate for the hydraulic actuator dynamics by using a load-compensated velocity feedforward loop and to increase the bandwidth by using a pressure feed backloop. Shaping filter techniques have been applied as a feedforward controller to avoid structural vibrations during operation. Among various types of shaping filter methods investigated an approach, referred to as a ''feedforward simulation filter'' that uses embedded simulation, has been presented

  12. Observer-Based Robust Control for Hydraulic Velocity Control System

    Directory of Open Access Journals (Sweden)

    Wei Shen

    2013-01-01

    Full Text Available This paper investigates the problems of robust stabilization and robust control for the secondary component speed control system with parameters uncertainty and load disturbance. The aim is to enhance the control performance of hydraulic system based on Common Pressure Rail (CPR. Firstly, a mathematical model is presented to describe the hydraulic control system. Then a novel observer is proposed, and an observed-based control strategy is designed such that the closed-loop system is asymptotically stable and satisfies the disturbance attenuation level. The condition for the existence of the developed controller can by efficiently solved by using the MATLAB software. Finally, simulation results are provided to demonstrate the effectiveness of the proposed method.

  13. Hydraulic screw fastening devices - design, maintenance, operational experience

    International Nuclear Information System (INIS)

    Lachner.

    1976-01-01

    With hydraulic screw fastening devices, pretension values with a maximum deviation of +-2.5% from the rated value can be achieved. This high degree of pretension accuracy is of considerable importance with regard to the safety factor required for the screw connection between reactor vessel head and reactor vessel. The operating rhythm of a nuclear power station with its refuelling art regular intervals makes further demands on the screw fastening device, in particular in connection with the transport of screws and for nuts. The necessary installations extend the screw fastening device into a combination of a high-pressure hydraulic cylinder system with an electrical or pneumoelectrical driving unit and an electrical control unit. Maintenance work is complicated by the large number of identical, highly stressed structural elements in connection with an unfavourable relation operating time/outage time. The problems have been perpetually reduced by close cooperation between the manufacturers and users of screw fastening devices. (orig./AK) [de

  14. A study on the thermal hydraulics in rod bundles

    International Nuclear Information System (INIS)

    Chung, Moon Ki; Yang, Sun Kyu

    1989-03-01

    In order to improve the thermal hydraulic characteristics of the nuclear reactor core, it is necessary to obtain better understanding of the coolant flow and the enthalpy distribution in complex rod bundle geometries. The purpose of this report is to obtain a comprehensive survey on the thermal hydraulic in rod bundles from both experimental and numerical point of view. From references on experimental study, measurement methods and results of the flow velocity and the pressure drop in the subchannels of rod bundles are expressed. The microscopic flow characteristics of the subchannels and spacer grid effect on the flow structure are described. Physical phenomena and measurement methods of the secondary flow are also described. From references on the numerical study, general numerical methods are expressed. Numerical studies on the laminar flow and turbulent flow such as 1-equation and 2-equation model are reviewed.(Author)

  15. Development and industrial tests of the first LNG hydraulic turbine system in China

    Directory of Open Access Journals (Sweden)

    Jie Chen

    2016-10-01

    Full Text Available The cryogenic hydraulic turbine can be used to replace the conventional J–T valve for LNG or mixed refrigerant throttling and depressurization in a natural gas liquefaction plant. This advanced technology is not only to enhance the efficiency of the liquefaction plant, but to usher a new trend in the development of global liquefaction technologies. China has over 136 liquefaction plants, but the cryogenic hydraulic turbines have not been deployed in industrial utilization. In addition, these turbines cannot be manufactured domestically. In this circumstance, through working on the key technologies for LNG hydraulic turbine process & control system development, hydraulic model optimization design, structure design and manufacturing, the first domestic cryogenic hydraulic turbine with a flow rate of 40 m3/h was developed to recover the pressure energy from the LNG of cold box. The turbine was installed in the CNOOC Zhuhai Natural Gas Liquefaction Plant for industrial tests under multiple working conditions, including start-stop, variable flow rates and variable rotation speeds. Test results show that the domestic LNG cryogenic hydraulic turbine has satisfactory mechanical and operational performances at low temperatures as specified in design. In addition, the process & control system and frequency-conversion power-generation system of the turbine system are designed properly to automatically and smoothly replace the existing LNG J–T valve. As a result, the domestic LNG cryogenic hydraulic turbine system can improve LNG production by an average of 2% and generate power of 8.3 kW.

  16. Dynamic characterization of partially saturated engineered porous media and gas diffusion layers using hydraulic admittance

    Science.gov (United States)

    Cheung, Perry; Fairweather, Joseph D.; Schwartz, Daniel T.

    2012-09-01

    Simple laboratory methods for determining liquid water distribution in polymer electrolyte membrane fuel cell gas diffusion layers (GDLs) are needed to engineer better GDL materials. Capillary pressure vs. liquid saturation measurements are attractive, but lack the ability to probe the hydraulic interconnectivity and distribution within the pore structure. Hydraulic admittance measurements of simple capillary bundles have recently been shown to nicely measure characteristics of the free-interfaces and hydraulic path. Here we examine the use of hydraulic admittance with a succession of increasingly complex porous media, starting with a laser-drilled sample with 154 asymmetric pores and progress to the behavior of Toray TGP-H090 carbon papers. The asymmetric laser-drilled sample clearly shows hydraulic admittance measurements are sensitive to sample orientation, especially when examined as a function of saturation state. Finite element modeling of the hydraulic admittance is consistent with experimental measurements. The hydraulic admittance spectra from GDL samples are complex, so we examine trends in the spectra as a function of wet proofing (0% and 40% Teflon loadings) as well as saturation state of the GDL. The presence of clear peaks in the admittance spectra for both GDL samples suggests a few pore types are largely responsible for transporting liquid water.

  17. Simulation of proportional control of hydraulic actuator using digital hydraulic valves

    Science.gov (United States)

    Raghuraman, D. R. S.; Senthil Kumar, S.; Kalaiarasan, G.

    2017-11-01

    Fluid power systems using oil hydraulics in earth moving and construction equipment have been using proportional and servo control valves for a long time to achieve precise and accurate position control backed by system performance. Such valves are having feedback control in them and exhibit good response, sensitivity and fine control of the actuators. Servo valves and proportional valves are possessing less hysteresis when compared to on-off type valves, but when the servo valve spools get stuck in one position, a high frequency called as jitter is employed to bring the spool back, whereas in on-off type valves it requires lesser technology to retract the spool. Hence on-off type valves are used in a technology known as digital valve technology, which caters to precise control on slow moving loads with fast switching times and with good flow and pressure control mimicking the performance of an equivalent “proportional valve” or “servo valve”.

  18. High speed hydraulically-actuated operating system for an electric circuit breaker

    Science.gov (United States)

    Iman, Imdad

    1983-06-07

    This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a breaker-opening piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A dashpotting mechanism operating separately from the hydraulic actuating system is provided, thereby reducing flow restriction interference with breaker opening.

  19. Thermal-hydraulic analysis of PWR core including intermediate flow mixers with the THYC code

    International Nuclear Information System (INIS)

    Mur, J.; Meignin, J.C.

    1997-07-01

    Departure from nucleate boiling (DNB) is one of the major limiting factors of pressurized water reactors (PWRs). Safety requires that occurrence of DNB should be precluded under normal or incidental operating conditions. The thermal-hydraulic THYC code developed by EDF is described. The code is devoted to heat and mass transfer in nuclear components. Critical Heat Flux (CHF) is predicted from local thermal-hydraulic parameters such as pressure, mass flow rate, and quality. A three stage methodology to evaluate thermal margins in order to perform standard core design is described. (K.A.)

  20. Thermal-hydraulic analysis of PWR core including intermediate flow mixers with the THYC code

    Energy Technology Data Exchange (ETDEWEB)

    Mur, J. [Electricite de France (EDF), 78 - Chatou (France); Meignin, J.C. [Electricite de France (EDF), 69 - Villeurbanne (France)

    1997-07-01

    Departure from nucleate boiling (DNB) is one of the major limiting factors of pressurized water reactors (PWRs). Safety requires that occurrence of DNB should be precluded under normal or incidental operating conditions. The thermal-hydraulic THYC code developed by EDF is described. The code is devoted to heat and mass transfer in nuclear components. Critical Heat Flux (CHF) is predicted from local thermal-hydraulic parameters such as pressure, mass flow rate, and quality. A three stage methodology to evaluate thermal margins in order to perform standard core design is described. (K.A.) 8 refs.

  1. Dimensionless Energy Conversion Characteristics of an Air-Powered Hydraulic Vehicle

    Directory of Open Access Journals (Sweden)

    Dongkai Shen

    2018-02-01

    Full Text Available Due to the advantages of resource conservation and less exhaust emissions, compressed air-powered vehicle has attracted more and more attention. To improve the power and efficiency of air-powered vehicle, an air-powered hydraulic vehicle was proposed. As the main part of the air-powered hydraulic vehicles, HP transformer (short for Hydropneumatic transformer is used to convert the pneumatic power to higher hydraulic power. In this study, to illustrate the energy conversion characteristics of air-powered hydraulic vehicle, dimensionless mathematical model of the vehicle’s working process was set up. Through experimental study on the vehicle, the dimensionless model was verified. Through simulation study on the vehicle, the following can be obtained: firstly, the increase of the hydraulic chamber orifice and the area ratio of the pistons can lead to a higher output power, while output pressure is just the opposite. Moreover, the increase of the output pressure and the aperture of the hydraulic chamber can lead to a higher efficiency, while area ratio of the pistons played the opposite role. This research can be referred to in the performance and design optimization of the HP transformers.

  2. Thermo-Hydraulic Modelling of Buffer and Backfill

    International Nuclear Information System (INIS)

    Pintado, X.; Rautioaho, E.

    2013-09-01

    The temporal evolution of saturation, liquid pressure and temperature in the components of the engineered barrier system was studied using numerical methods. A set of laboratory tests was conducted to calibrate the parameters employed in the models. The modelling consisted of thermal, hydraulic and thermo-hydraulic analysis in which the significant thermo-hydraulic processes, parameters and features were identified. CODE B RIGHT was used for the finite element modelling and supplementary calculations were conducted with analytical methods. The main objective in this report is to improve understanding of the thermo-hydraulic processes and material properties that affect buffer behaviour in the Olkiluoto repository and to determine the parametric requirements of models for the accurate prediction of this behaviour. The analyses consisted of evaluating the influence of initial canister temperature and gaps in the buffer, and the role played by fractures and the rock mass located between fractures in supplying water for buffer and backfill saturation. In the thermo-hydraulic analysis, the primary processes examined were the effects of buffer drying near the canister on temperature evolution and the manner in which heat flow affects the buffer saturation process. Uncertainties in parameters and variations in the boundary conditions, modelling geometry and thermo-hydraulic phenomena were assessed with a sensitivity analysis. The material parameters, constitutive models, and assumptions made were carefully selected for all the modelling cases. The reference parameters selected for the simulations were compared and evaluated against laboratory measurements. The modelling results highlight the importance of understanding groundwater flow through the rock mass and from fractures in the rock in order to achieve reliable predictions regarding buffer saturation, since saturation times could range from a few years to tens of thousands of years depending on the hydrogeological

  3. Hydraulic limits preceding mortality in a piñon-juniper woodland under experimental drought.

    Science.gov (United States)

    Plaut, Jennifer A; Yepez, Enrico A; Hill, Judson; Pangle, Robert; Sperry, John S; Pockman, William T; McDowell, Nate G

    2012-09-01

    Drought-related tree mortality occurs globally and may increase in the future, but we lack sufficient mechanistic understanding to accurately predict it. Here we present the first field assessment of the physiological mechanisms leading to mortality in an ecosystem-scale rainfall manipulation of a piñon-juniper (Pinus edulis-Juniperus monosperma) woodland. We measured transpiration (E) and modelled the transpiration rate initiating hydraulic failure (E(crit) ). We predicted that isohydric piñon would experience mortality after prolonged periods of severely limited gas exchange as required to avoid hydraulic failure; anisohydric juniper would also avoid hydraulic failure, but sustain gas exchange due to its greater cavitation resistance. After 1 year of treatment, 67% of droughted mature piñon died with concomitant infestation by bark beetles (Ips confusus) and bluestain fungus (Ophiostoma spp.); no mortality occurred in juniper or in control piñon. As predicted, both species avoided hydraulic failure, but safety margins from E(crit) were much smaller in piñon, especially droughted piñon, which also experienced chronically low hydraulic conductance. The defining characteristic of trees that died was a 7 month period of near-zero gas exchange, versus 2 months for surviving piñon. Hydraulic limits to gas exchange, not hydraulic failure per se, promoted drought-related mortality in piñon pine. © 2012 Blackwell Publishing Ltd.

  4. Experimental Study of Hydraulic Control Rod Drive Mechanism for Passive IN-core Cooling System of Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Guk; Kim, Kyung Mo; Jeong, Yeong Shin; Bang, In Cheol [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    CAREM 25 (27 MWe safety systems using hydraulic control rod drives (CRD) studied critical issues that were rod drops with interrupted flow [3]. Hydraulic control rod drive suggested fast shutdown condition using a large gap between piston and cylinder in order to fast drop of neutron absorbing rods. A Passive IN-core Cooling system (PINCs) was suggested for safety enhancement of pressurized water reactors (PWR), small modular reactor (SMR), sodium fast reactor (SFR) in UNIST. PINCs consist of hydraulic control rod drive mechanism (Hydraulic CRDM) and hybrid control rod assembly with heat pipe combined with control rod. The schematic diagram of the hydraulic CRDM for PINCs is shown in Fig. 1. The experimental results show the steady state and transient behavior of the upper cylinder at a low pressure and low temperature. The influence of the working fluid temperature and cylinder mass are investigated. Finally, the heat removal between evaporator section and condenser section is compared with or without the hybrid control rod. Heat removal test of the hybrid heat pipe with hydraulic CRDM system showed the heat transfer coefficient of the bundle hybrid control rod and its effect on evaporator pool. The preliminary test both hydraulic CRDM and heat removal system was conducted, which showed the possibility of the in-core hydraulic drive system for application of PINCs.

  5. Water transport through tall trees: A vertically-explicit, analytical model of xylem hydraulic conductance in stems.

    Science.gov (United States)

    Couvreur, Valentin; Ledder, Glenn; Manzoni, Stefano; Way, Danielle A; Muller, Erik B; Russo, Sabrina E

    2018-05-08

    Trees grow by vertically extending their stems, so accurate stem hydraulic models are fundamental to understanding the hydraulic challenges faced by tall trees. Using a literature survey, we showed that many tree species exhibit continuous vertical variation in hydraulic traits. To examine the effects of this variation on hydraulic function, we developed a spatially-explicit, analytical water transport model for stems. Our model allows Huber ratio, stem-saturated conductivity, pressure at 50% loss of conductivity, leaf area, and transpiration rate to vary continuously along the hydraulic path. Predictions from our model differ from a matric flux potential model parameterized with uniform traits. Analyses show that cavitation is a whole-stem emergent property resulting from nonlinear pressure-conductivity feedbacks that, with gravity, cause impaired water transport to accumulate along the path. Because of the compounding effects of vertical trait variation on hydraulic function, growing proportionally more sapwood and building tapered xylem with height, as well as reducing xylem vulnerability only at branch tips while maintaining transport capacity at the stem base, can compensate for these effects. We therefore conclude that the adaptive significance of vertical variation in stem hydraulic traits is to allow trees to grow tall and tolerate operating near their hydraulic limits. This article is protected by copyright. All rights reserved.

  6. Performance and efficiency of a hydraulic hybrid powertrain

    Energy Technology Data Exchange (ETDEWEB)

    Karbaschian, Mohammad Ali [Duisburg-Essen Univ. (Germany). Faculty of Engineering

    2012-11-01

    Hydraulic hybrid powertrains are considered to be a promising technology to save energy and reduce emission in specific automotive fields because of their high power density, components lifetime, and long lasting experience in industries compared to electric hybrid powertrains. Within the first part of the paper, a very brief literature survey on hydraulic hybrid vehicle systems (HHVS) and the related dynamical behaviour is given. No specific activities to improve the efficiency of these systems were detected. Related literature with respect to optimization mainly deals with the management of the system's energy flows trying to control the engine operation point and the high pressure in the system. In the second part, a small simulation study is presented. Therefore, hybrid systems are generally assumed as a Multi-Input-Multi-Output (MIMO) system. The effect of key variables (i.e. accumulator size and pressure, pump/motor displacement and efficiency, valve dynamics) on the system is discussed. The results show that the volume displacement of pump and motor, the performance of the engine, and the state of charge of the accumulator are the most important parameters to specify the efficiency and performance of the hydraulic hybrid powertrain. Additionally, a hybrid hydraulic powertrain with an adjustable state of charge accumulator is compared with one whose state of charge is constant. The result shows the improvement of braking performance and fuel savings. The goal is to optimize the parameters of the system based on the simultaneous consideration of the three (or more) variables for a given load profile with respect to given objectives. (orig.)

  7. Progress of the DUPIC fuel compatibility analysis (II) - thermal-hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hwan; Choi, Hang Bok

    2005-03-01

    Thermal-hydraulic compatibility of the DUPIC fuel bundle with a 713 MWe Canada deuterium uranium (CANDU-6) reactor was studied by using both the single channel and sub-channel analysis methods. The single channel analysis provides the fuel channel flow rate, pressure drop, critical channel power, and the channel exit quality, which are assessed against the thermal-hydraulic design requirements of the CANDU-6 reactor. The single channel analysis by the NUCIRC code showed that the thermal-hydraulic performance of the DUPIC fuel is not different from that of the standard CANDU fuel. Regarding the local flow characteristics, the sub-channel analysis also showed that the uncertainty of the critical channel power calculation for the DUPIC fuel channel is very small. As a result, both the single and sub-channel analyses showed that the key thermal-hydraulic parameters of the DUPIC fuel channel do not deteriorate compared to the standard CANDU fuel channel.

  8. An evaluation of a hubless inducer and a full flow hydraulic turbine driven inducer boost pump

    Science.gov (United States)

    Lindley, B. K.; Martinson, A. R.

    1971-01-01

    The purpose of the study was to compare the performance of several configurations of hubless inducers with a hydrodynamically similar conventional inducer and to demonstrate the performance of a full flow hydraulic turbine driven inducer boost pump using these inducers. A boost pump of this type consists of an inducer connected to a hydraulic turbine with a high speed rotor located in between. All the flow passes through the inducer, rotor, and hydraulic turbine, then into the main pump. The rotor, which is attached to the main pump shaft, provides the input power to drive the hydraulic turbine which, in turn, drives the inducer. The inducer, rotating at a lower speed, develops the necessary head to prevent rotor cavitation. The rotor speed is consistent with present main engine liquid hydrogen pump designs and the overall boost pump head rise is sufficient to provide adequate main pump suction head. This system would have the potential for operating at lower liquid hydrogen tank pressures.

  9. The application of hydraulics in the 2,000 kW wind turbine generator

    Science.gov (United States)

    Onufreiczuk, S.

    1978-01-01

    A 2000 kW turbine generator using hydraulic power in two of its control systems is being built under the management of NASA Lewis Research Center. The hydraulic systems providing the control torques and forces for the yaw and blade pitch control systems are discussed. The yaw-drive-system hydraulic supply provides the power for positioning the nacelle so that the rotary axis is kept in line with the direction of the prevailing wind, as well as pressure to the yaw and high speed shaft brakes. The pitch-change-mechanism hydraulic system provides the actuation to the pitch change mechanism and permits feathering of the blades during an emergency situation. It operates in conjunction with the overall windmill computer system, with the feather control permitting slewing control flow to pass from the servo valve to the actuators without restriction.

  10. Full vessel CFD analysis on thermal-hydraulic characteristics of CPR1000 PWR

    International Nuclear Information System (INIS)

    Chao Yanmeng; Yang Lixin; Zhang Mingqian

    2014-01-01

    To obtain flow distributions and thermal-hydraulic properties in a full vessel PWR under limited computation ability and time, a full vessel simulation model of CPR1000 was built based on two simplification methods. One simplified the inner geometry of the control rod guide tubes using equivalent flow area. Another substituted the core by a porous domain to maintain the pressure drop and temperature rise. After the computation, global and localized flow distributions, hydraulic loads of some main assemblies were obtained, as well as other thermal-hydraulic properties. The results indicate the flow distribution in the full vessel is asymmetrical. Therefore it is essential to use the full vessel model to simulate. The calculated thermal-hydraulic characteristics agree well with the operation statistics, providing the reference data for the reactor safety operation. (authors)

  11. Numerical simulation of the two-phase flows in a hydraulic coupling by solving VOF model

    International Nuclear Information System (INIS)

    Luo, Y; Zuo, Z G; Liu, S H; Fan, H G; Zhuge, W L

    2013-01-01

    The flow in a partially filled hydraulic coupling is essentially a gas-liquid two-phase flow, in which the distribution of two phases has significant influence on its characteristics. The interfaces between the air and the liquid, and the circulating flows inside the hydraulic coupling can be simulated by solving the VOF two-phase model. In this paper, PISO algorithm and RNG k–ε turbulence model were employed to simulate the phase distribution and the flow field in a hydraulic coupling with 80% liquid fill. The results indicate that the flow forms a circulating movement on the torus section with decreasing speed ratio. In the pump impeller, the air phase mostly accumulates on the suction side of the blades, while liquid on the pressure side; in turbine runner, air locates in the middle of the flow passage. Flow separations appear near the blades and the enclosing boundaries of the hydraulic coupling

  12. Detecting Output Pressure Change of Positive-Displacement Pump by Phase Trajectory Method

    Directory of Open Access Journals (Sweden)

    Jerzy Stojek

    2010-06-01

    Full Text Available The monitoring of hydraulic system condition change during its exploitation ran its complex problem. The main task is to identifyearly phase damage of hydraulic system elements (pumps, valves, ect. in order to take decision which can avoid hydraulic system breakdown. This paper presents the possibility of phase trajectories use in detecting output pressure change of hydraulic system causedby positive-displacement pump wear.

  13. Determination of thermal-hydraulic loads on reactor internals in a DBA-situation

    International Nuclear Information System (INIS)

    Ville Lestinen; Timo Toppila

    2005-01-01

    Full text of publication follows: According to Finnish regulatory requirements, reactor internals have to stay intact in a design basis accident (DBA) situation, so that control rods can still penetrate into the core. To fulfill this demand some criteria must be followed in periodical in-service inspections. This is the motivation for studying and developing more detailed methods for analysis of thermal-hydraulic loads on reactor internals during the DBA-situation for the Loviisa NPP in Finland. The objective of this research program is to connect thermal-hydraulic and mechanical analysis methods with the goal to produce a reliable method for determination of thermal-hydraulic and mechanical loads on reactor internals in the accident situation. The tools studied are thermal-hydraulic system codes, computational fluid dynamics (CFD) codes and finite element analysis (FEA) codes. This paper concentrates mainly on thermal-hydraulic part of the research, but also the mechanical aspects are discussed. Firstly, the paper includes a short literary review of the available methods to analyse the described problem including both thermal-hydraulic and structural analysis parts. Secondly, different possibilities to carry out thermal-hydraulic analyses have been studied. The DBA-case includes complex physical phenomena and therefore modelling is difficult. The accident situation can be for example LLOCA. When the pipe has broken, the pressure decreases and water starts to evaporate, which consumes energy and that way limits the pressure decrease. After some period of time, the system reaches a new equilibrium state. To perform exact thermal-hydraulic analysis also two phase phenomena must be included. Therefore CFD codes are not capable of modelling the DBA situation very well, but the use of CFD codes requires that the effect of two phase flow must be added somehow. One method to calculate two phase phenomena with CFD codes is to use thermal-hydraulic system codes to calculate

  14. Engine including hydraulically actuated valvetrain and method of valve overlap control

    Science.gov (United States)

    Cowgill, Joel [White Lake, MI

    2012-05-08

    An exhaust valve control method may include displacing an exhaust valve in communication with the combustion chamber of an engine to an open position using a hydraulic exhaust valve actuation system and returning the exhaust valve to a closed position using the hydraulic exhaust valve actuation assembly. During closing, the exhaust valve may be displaced for a first duration from the open position to an intermediate closing position at a first velocity by operating the hydraulic exhaust valve actuation assembly in a first mode. The exhaust valve may be displaced for a second duration greater than the first duration from the intermediate closing position to a fully closed position at a second velocity at least eighty percent less than the first velocity by operating the hydraulic exhaust valve actuation assembly in a second mode.

  15. A multi-packer completion to measure hydraulic heads in a lightly fractured area in the Oxfordian limestone

    International Nuclear Information System (INIS)

    Scholz, E.; Cruchaudet, M.; Delay, J.; Piedevache, M.

    2010-01-01

    Document available in extended abstract form only. Andra has designed a new type of borehole completion in order to monitor simultaneously hydraulic heads. This completion is installed in a 420 m deep borehole drilled in the Oxfordian limestone formation. The borehole is located in the South-West of Andra's Underground Research Laboratory (URL) in a lightly fractured area. The multi-packer completion is built and installed by Solexperts. This device is composed of five measurement intervals isolated with rubber expandable packers and supported by stainless steel tubing. The packers are inflated with water at a pressure of 10 bars above the water pressure at that depth. Each measurement interval comprises an interval module embedding a pressure / temperature gauge connected to the interval through a filter. The gauges are connected through one cable to a data acquisition system on surface. This completion is removable. The packers can be deflated and the completion can be installed in another borehole. The packers are positioned in the EST461 borehole according to the caliper logging and the results of permeability tests. The hydraulic head measurements are compared with the local rainfall. Interval 1 (the deepest) shows a stable hydraulic head whereas intervals 2 to 5 show hydraulic head variations. The amplitude of the hydraulic head variations are closely related to the interval depth: the deepest the interval, the lowest the hydraulic head variation. Hydraulic heads in intervals 4 and 5 are similar. These intervals are probably connected. (authors)

  16. Calculation of saturated hydraulic conductivity of bentonite

    International Nuclear Information System (INIS)

    He Jun

    2006-01-01

    Hydraulic conductivity test has some defects such as weak repeatability, time-consuming. Taking bentonite as dual porous media, the calculation formula of the distance, d 2 , between montmorillonite in intraparticle pores is deduced. Improved calculated method of hydraulic conductivity is obtained using d 2 and Poiseuille law. The method is valid through the comparison with results of test and other methods. The method is very convenient to calculate hydraulic conductivity of bentonite of certain montmorillonite content and void ratio. (authors)

  17. Reactor Thermal Hydraulic Numerical Calculation And Modeling

    International Nuclear Information System (INIS)

    Duong Ngoc Hai; Dang The Ba

    2008-01-01

    In the paper the results of analysis of thermal hydraulic state models using the numerical codes such as COOLOD, EUREKA and RELAP5 for simulation of the reactor thermal hydraulic states are presented. The calculations, analyses of reactor thermal hydraulic state and safety were implemented using different codes. The received numerical results, which were compared each to other, to experiment measurement of Dalat (Vietnam) research reactor and published results, show their appropriateness and capacity for analyses of different appropriate cases. (author)

  18. Dynamic response characteristics evaluation of hydrostatic bearing in hydraulic piston pump/motor

    International Nuclear Information System (INIS)

    Ham, Young Bog; Yun, So Nam; Kim, Dong Soo; Choi, Byoung Oh; Kim, Sung Dong

    2001-01-01

    In swash plate type axial piston hydraulic pump and motor, the piston shoe is periodically pressurized with square function shape by supply pressure load as rotation of cylinder barrel. Therefore the recess pressure ono bottom part of piston shoe is suddenly increase through orifice in the piston shoe. In this study, we simulated that the frequency response of the recess pressure against with change of supply pressure with analysis tool. Also, we evaluate the dynamic response characteristics of overbalanced hydrostatic bearing with change of the orifice diameter

  19. Measurement of in-situ hydraulic conductivity in the Cretaceous Pierre Shale

    International Nuclear Information System (INIS)

    Neuzil, C.E.; Bredehoeft, J.D.

    1981-01-01

    A recent study of the hydrology of the Cretaceous Pierre Shale utilized three techniques for measuring the hydraulic conductivity of tight materials. Regional hydraulic conductivity was obtained from a hydrodynamic model analysis of the aquifer-aquitard system which includes the Pierre Shale. Laboratory values were obtained from consolidation tests on core samples. In-situ values of hydraulic conductivity were obtained by using a borehole slug test designed specifically for tight formations. The test is conducted by isolating a portion of the borehole with one or two packers, abruptly pressurizing the shut-in portion, and recording the pressure decay with time. The test utilizes the analytical solution for pressure decay as water flows into the surrounding formation. Consistent results were obtained using the test on three successively smaller portions of a borehole in the Pierre Shale. The in-situ tests and laboratory tests yielded comparable values; the regional hydraulic conductivity was two to three orders of magnitude larger. This suggests that the lower values represent intergranular hydraulic conductivity of the intact shale and the regional values represent secondary permeability due to fractures. Calculations based on fracture flow theory demonstrate that small fractures could account for the observed differences

  20. CCP Sensitivity Analysis by Variation of Thermal-Hydraulic Parameters of Wolsong-3, 4

    Energy Technology Data Exchange (ETDEWEB)

    You, Sung Chang [KHNP, Daejeon (Korea, Republic of)

    2016-10-15

    The PHWRs are tendency that ROPT(Regional Overpower Protection Trip) setpoint is decreased with reduction of CCP(Critical Channel Power) due to aging effects. For this reason, Wolsong unit 3 and 4 has been operated less than 100% power due to the result of ROPT setpoint evaluation. Typically CCP for ROPT evaluation is derived at 100% PHTS(Primary Heat Transport System) boundary conditions - inlet header temperature, header to header different pressure and outlet header pressure. Therefore boundary conditions at 100% power were estimated to calculate the thermal-hydraulic model at 100% power condition. Actually thermal-hydraulic boundary condition data for Wolsong-3 and 4 cannot be taken at 100% power condition at aged reactor condition. Therefore, to create a single-phase thermal-hydraulic model with 80% data, the validity of the model was confirmed at 93.8%(W3), 94.2%(W4, in the two-phase). And thermal-hydraulic boundary conditions at 100% power were calculated to use this model. For this reason, the sensitivities by varying thermal-hydraulic parameters for CCP calculation were evaluated for Wolsong unit 3 and 4. For confirming the uncertainties by variation PHTS model, sensitivity calculations were performed by varying of pressure tube roughness, orifice degradation factor and SG fouling factor, etc. In conclusion, sensitivity calculation results were very similar and the linearity was constant.

  1. Hydraulic properties of rice and the response of gas exchange to water stress.

    Science.gov (United States)

    Stiller, Volker; Lafitte, H Renee; Sperry, John S

    2003-07-01

    We investigated the role of xylem cavitation, plant hydraulic conductance, and root pressure in the response of rice (Oryza sativa) gas exchange to water stress. In the field (Philippines), the percentage loss of xylem conductivity (PLC) from cavitation exceeded 60% in leaves even in watered controls. The PLC versus leaf water potential relationship indicated diurnal refilling of cavitated xylem. The leaf water potential causing 50 PLC (P(50)) was -1.6 MPa and did not differ between upland versus lowland rice varieties. Greenhouse-grown varieties (Utah) were more resistant to cavitation with a 50 PLC of -1.9 MPa but also showed no difference between varieties. Six-day droughts caused concomitant reductions in leaf-specific photosynthetic rate, leaf diffusive conductance, and soil-leaf hydraulic conductance that were associated with cavitation-inducing water potentials and the disappearance of nightly root pressure. The return of root pressure after drought was associated with the complete recovery of leaf diffusive conductance, leaf-specific photosynthetic rate, and soil-leaf hydraulic conductance. Root pressure after the 6-d drought (61.2 +/- 8.8 kPa) was stimulated 7-fold compared with well-watered plants before drought (8.5 +/- 3.8 kPa). The results indicate: (a) that xylem cavitation plays a major role in the reduction of plant hydraulic conductance during drought, and (b) that rice can readily reverse cavitation, possibly aided by nocturnal root pressure.

  2. Thermal-Hydraulic Results for the Boiling Water Reactor Dry Cask Simulator.

    Energy Technology Data Exchange (ETDEWEB)

    Durbin, Samuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lindgren, Eric R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    The thermal performance of commercial nuclear spent fuel dry storage casks is evaluated through detailed numerical analysis. These modeling efforts are completed by the vendor to demonstrate performance and regulatory compliance. The calculations are then independently verified by the Nuclear Regulatory Commission (NRC). Carefully measured data sets generated from testing of full sized casks or smaller cask analogs are widely recognized as vital for validating these models. Recent advances in dry storage cask designs have significantly increased the maximum thermal load allowed in a cask in part by increasing the efficiency of internal conduction pathways and by increasing the internal convection through greater canister helium pressure. These same canistered cask systems rely on ventilation between the canister and the overpack to convect heat away from the canister to the environment for both aboveground and belowground configurations. While several testing programs have been previously conducted, these earlier validation attempts did not capture the effects of elevated helium pressures or accurately portray the external convection of aboveground and belowground canistered dry cask systems. The purpose of this investigation was to produce validation-quality data that can be used to test the validity of the modeling presently used to determine cladding temperatures in modern vertical dry casks. These cladding temperatures are critical to evaluate cladding integrity throughout the storage cycle. To produce these data sets under well-controlled boundary conditions, the dry cask simulator (DCS) was built to study the thermal-hydraulic response of fuel under a variety of heat loads, internal vessel pressures, and external configurations. An existing electrically heated but otherwise prototypic BWR Incoloy-clad test assembly was deployed inside of a representative storage basket and cylindrical pressure vessel that represents a vertical canister system. The symmetric

  3. Investigation of hydraulic transmission noise sources

    Science.gov (United States)

    Klop, Richard J.

    Advanced hydrostatic transmissions and hydraulic hybrids show potential in new market segments such as commercial vehicles and passenger cars. Such new applications regard low noise generation as a high priority, thus, demanding new quiet hydrostatic transmission designs. In this thesis, the aim is to investigate noise sources of hydrostatic transmissions to discover strategies for designing compact and quiet solutions. A model has been developed to capture the interaction of a pump and motor working in a hydrostatic transmission and to predict overall noise sources. This model allows a designer to compare noise sources for various configurations and to design compact and inherently quiet solutions. The model describes dynamics of the system by coupling lumped parameter pump and motor models with a one-dimensional unsteady compressible transmission line model. The model has been verified with dynamic pressure measurements in the line over a wide operating range for several system structures. Simulation studies were performed illustrating sensitivities of several design variables and the potential of the model to design transmissions with minimal noise sources. A semi-anechoic chamber has been designed and constructed suitable for sound intensity measurements that can be used to derive sound power. Measurements proved the potential to reduce audible noise by predicting and reducing both noise sources. Sound power measurements were conducted on a series hybrid transmission test bench to validate the model and compare predicted noise sources with sound power.

  4. Hydraulic fracturing in granite under geothermal conditions

    Science.gov (United States)

    Solberg, P.; Lockner, D.; Byerlee, J.D.

    1980-01-01

    The experimental hydraulic fracturing of granite under geothermal conditions produces tensile fracture at rapid fluid injection rates and shear fracture at slow injection rates and elevated differential stress levels. A sudden burst of acoustic emission activity accompanies tensile fracture formation whereas the acoustic emission rate increases exponentially prior to shear fracture. Temperature does not significantly affect the failure mechanism, and the experimental results have not demonstrated the occurrence of thermal fracturing. A critical result of these experiments is that fluid injection at intermediate rates and elevated differential stress levels increases permeability by more than an order of magnitude without producing macroscopic fractures, and low-level acoustic emission activity occurs simultaneously near the borehole and propagates outward into the specimen with time. Permeability measurements conducted at atmospheric pressure both before and after these experiments show that increased permeability is produced by permanent structural changes in the rock. Although results of this study have not demonstrated the occurrence of thermal fracturing, they suggest that fluid injection at certain rates in situ may markedly increase local permeability. This could prove critical to increasing the efficiency of heat exchange for geothermal energy extraction from hot dry rock. ?? 1980.

  5. Hydraulic fracturing - an attempt of DEM simulation

    Science.gov (United States)

    Kosmala, Alicja; Foltyn, Natalia; Klejment, Piotr; Dębski, Wojciech

    2017-04-01

    Hydraulic fracturing is a technique widely used in oil, gas and unconventional reservoirs exploitation in order to enable the oil/gas to flow more easily and enhance the production. It relays on pumping into a rock a special fluid under a high pressure which creates a set of microcracks which enhance porosity of the reservoir rock. In this research, attempt of simulation of such hydrofracturing process using the Discrete Element Method approach is presented. The basic assumption of this approach is that the rock can be represented as an assembly of discrete particles cemented into a rigid sample (Potyondy 2004). An existence of voids among particles simulates then a pore system which can be filled out by fracturing fluid, numerically represented by much smaller particles. Following this microscopic point of view and its numerical representation by DEM method we present primary results of numerical analysis of hydrofracturing phenomena, using the ESyS-Particle Software. In particular, we consider what is happening in distinct vicinity of the border between rock sample and fracking particles, how cracks are creating and evolving by breaking bonds between particles, how acoustic/seismic energy is releasing and so on. D.O. Potyondy, P.A. Cundall. A bonded-particle model for rock. International Journal of Rock Mechanics and Mining Sciences, 41 (2004), pp. 1329-1364.

  6. The successful use of transverse hydraulic fractures from horizontal wellbores

    Energy Technology Data Exchange (ETDEWEB)

    Crosby, D. G.; Yang, Z.; Rahman, S. S. [New South Wales Univ., NSW (Australia)

    1998-12-31

    Since a significant proportion of the world`s recoverable hydrocarbon resources exist in reservoirs possessing permeabilities of less than one milli-Darcy (mD), some form of permeability enhancement or stimulation is necessary if the hydrocarbons are to be exploited economically. Multi-stage, transversely fractured horizontal wellbores are shown to have the potential to greatly increase production from low permeability formations. To overcome the problems caused by near-wellbore tortuosity, common to wells with multiple fracturing from the same perforated interval, a criterion was devised which predicts the wellbore pressures to initiate secondary multiple transverse hydraulic fractures in close proximity to primary fractures. The criterion, confirmed by laboratory experiments, demonstrates that transversely fractured horizontal wellbores have limited capacities to resist the initiation of multiple fractures from adjacent perforations. This characteristic can be used in designing hydraulic fracture treatments to establish injection pressure limits or threshold pressures, above which additional multiple fractures will initiate and propagate from the wellbore. 23 refs., 1 tab., 10 figs.

  7. Nonlinear, Adaptive and Fault-tolerant Control for Electro-hydraulic Servo Systems

    DEFF Research Database (Denmark)

    Choux, Martin

    is designed and implemented on the test bed that successfully diagnoses internal or external leakages, friction variations in the actuator or fault related to pressure sensors. The presented algorithm uses the position and pressure measurements to detect and isolate faults, avoiding missed detection and false...... numerous attractive properties, hydraulic systems are always subject to potential leakages in their components, friction variation in their hydraulic actuators and deciency in their sensors. These violations of normal behaviour reduce the system performances and can lead to system failure...... if they are not detected early and handled. Moreover, the task of controlling electro hydraulic systems for high performance operations is challenging due to the highly nonlinear behaviour of such systems and the large amount of uncertainties present in their models. This thesis focuses on nonlinear adaptive fault...

  8. Linear hydraulic drive system for a Stirling engine

    Science.gov (United States)

    Walsh, Michael M.

    1984-02-21

    A hydraulic drive system operating from the periodic pressure wave produced by a Stirling engine along a first axis thereof and effecting transfer of power from the Stirling engine to a load apparatus therefor and wherein the movable, or working member of the load apparatus is reciprocatingly driven along an axis substantially at right angles to the first axis to achieve an arrangement of a Stirling engine and load apparatus assembly which is much shorter and the components of the load apparatus more readily accessible.

  9. Detection of cavitation vortex in hydraulic turbines using acoustic techniques

    International Nuclear Information System (INIS)

    Candel, I; Ioana, C; Bunea, F; Politehnica University of Bucharest (Romania))" data-affiliation=" (Power Engineering Faculty, Politehnica University of Bucharest (Romania))" >Dunca, G; Politehnica University of Bucharest (Romania))" data-affiliation=" (Power Engineering Faculty, Politehnica University of Bucharest (Romania))" >Bucur, D M; Division Technique Générale, Grenoble (France))" data-affiliation=" (Electricité de France, Division Technique Générale, Grenoble (France))" >Reeb, B; Ciocan, G D

    2014-01-01

    Cavitation phenomena are known for their destructive capacity in hydraulic machineries and are caused by the pressure decrease followed by an implosion when the cavitation bubbles find an adverse pressure gradient. A helical vortex appears in the turbine diffuser cone at partial flow rate operation and can be cavitating in its core. Cavity volumes and vortex frequencies vary with the under-pressure level. If the vortex frequency comes close to one of the eigen frequencies of the turbine, a resonance phenomenon may occur, the unsteady fluctuations can be amplified and lead to important turbine and hydraulic circuit damage. Conventional cavitation vortex detection techniques are based on passive devices (pressure sensors or accelerometers). Limited sensor bandwidths and low frequency response limit the vortex detection and characterization information provided by the passive techniques. In order to go beyond these techniques and develop a new active one that will remove these drawbacks, previous work in the field has shown that techniques based on acoustic signals using adapted signal content to a particular hydraulic situation, can be more robust and accurate. The cavitation vortex effects in the water flow profile downstream hydraulic turbines runner are responsible for signal content modifications. Basic signal techniques use narrow band signals traveling inside the flow from an emitting transducer to a receiving one (active sensors). Emissions of wide band signals in the flow during the apparition and development of the vortex embeds changes in the received signals. Signal processing methods are used to estimate the cavitation apparition and evolution. Tests done in a reduced scale facility showed that due to the increasing flow rate, the signal -- vortex interaction is seen as modifications on the received signal's high order statistics and bandwidth. Wide band acoustic transducers have a higher dynamic range over mechanical elements; the system

  10. HYTRAN: hydraulic transient code for investigating channel flow stability

    International Nuclear Information System (INIS)

    Kao, H.S.; Cardwell, W.R.; Morgan, C.D.

    1976-01-01

    HYTRAN is an analytical program used to investigate the possibility of hydraulic oscillations occurring in a reactor flow channel. The single channel studied is ordinarily the hot channel in the reactor core, which is parallel to other channels and is assumed to share a constant pressure drop with other channels. Since the channel of highest thermal state is studied, provision is made for two-phase flow that can cause a flow instability in the channel. HYTRAN uses the CHATA(1) program to establish a steady-state condition. A heat flux perturbation is then imposed on the channel, and the flow transient is calculated as a function of time

  11. Thermal and hydraulic analyses of the System 81 cold traps

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.

    1977-06-15

    Thermal and hydraulic analyses of the System 81 Type I and II cold traps were completed except for thermal transients analysis. Results are evaluated, discussed, and reported. Analytical models were developed to determine the physical dimensions of the cold traps and to predict the performance. The FFTF cold trap crystallizer performances were simulated using the thermal model. This simulation shows that the analytical model developed predicts reasonably conservative temperatures. Pressure drop and sodium residence time calculations indicate that the present design will meet the requirements specified in the E-Specification. Steady state temperature data for the critical regions were generated to assess the magnitude of the thermal stress.

  12. Thermal-hydraulic considerations for particle bed reactors

    Science.gov (United States)

    Benenati, R.; Araj, K. J.; Horn, F.

    In the design of particle bed reactor (PBR) cores, consideration must be given to the gas coolant channels and their configuration. Neutronics analysis provides the relative volume fractions of the component materials, but these must be arranged in such a manner as to allow proper cooling of all components by the gas flow at relatively low pressure drops. The thermal hydraulic aspects of this problem are addressed. A description of the computer model used in the analysis of the steady state condition is also included. Blowdown tests on hot particle bed fuel elements were carried out and are described.

  13. Verification Test of Hydraulic Performance for Reactor Coolant Pump

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Jun; Kim, Jae Shin; Ryu, In Wan; Ko, Bok Seong; Song, Keun Myung [Samjin Ind. Co., Seoul (Korea, Republic of)

    2010-01-15

    According to this project, basic design for prototype pump and model pump of reactor coolant pump and test facilities has been completed. Basic design for prototype pump to establish structure, dimension and hydraulic performance has been completed and through primary flow analysis by computational fluid dynamics(CFD), flow characteristics and hydraulic performance have been established. This pump was designed with mixed flow pump having the following design requirements; specific velocity(Ns); 1080.9(rpm{center_dot}m{sup 3}/m{center_dot}m), capacity; 3115m{sup 3}/h, total head ; 26.3m, pump speed; 1710rpm, pump efficiency; 77.0%, Impeller out-diameter; 349mm, motor output; 360kw, design pressure; 17MPaG. The features of the pump are leakage free due to no mechanical seal on the pump shaft which insures reactor's safety and law noise level and low vibration due to no cooling fan on the motor which makes eco-friendly product. Model pump size was reduced to 44% of prototype pump for the verification test for hydraulic performance of reactor coolant pump and was designed with mixed flow pump and canned motor having the following design requirements; specific speed(NS); 1060.9(rpm{center_dot}m{sup 3}/m{center_dot}m), capacity; 539.4m{sup 3}/h, total head; 21.0m, pump speed; 3476rpm, pump efficiency; 72.9%, Impeller out-diameter; 154mm, motor output; 55kw, design pressure; 1.0MPaG. The test facilities were designed for verification test of hydraulic performance suitable for pump performance test, homologous test, NPSH test(cavitation), cost down test and pressure pulsation test of inlet and outlet ports. Test tank was designed with testing capacity enabling up to 2000m{sup 3}/h and design pressure 1.0MPaG. Auxiliary pump was designed with centrifugal pump having capacity; 1100m{sup 3}/h, total head; 42.0m, motor output; 190kw

  14. Thermal-hydraulic characteristics of double flat core HCLWR

    International Nuclear Information System (INIS)

    Sugimoto, Jun; Iwamura, Takamichi; Okubo, Tsutomu; Murao, Yoshio

    1989-02-01

    A thermal-hydraulic characteristics of double flat core high conversion light water reactor (HCLWR) is described. The concept of flat core proposed by Ishiguro et al. is to achieve negative void reactivity coefficient in tight lattice core, and at the same time, high conversion ratio and high burnup can be obtainable. The proposed double flat core HCLWR, based on these physical advantages and the consideration of safety assurance, aims at efficient use of the pressure vessel space to produce comparable thermal output as current 3-loop PWRs. The present work revealed the following items concerning the thermalhydraulic feasibility of the double flat core HCLWR: (1) Main thermal-hydraulic parameters of the plant can be almost the same as current PWRs, showing the use of PWR standard components without major modifications except in core region. (2) Heat removal from the fuel rod in a steady operational condition has enough margin to the critical heat flux (CHF) limit, which is evaluated with the existing CHF correlations. (3) The calculation by REFLA code shows that the maximum cladding temperature in LOCA-reflood is estimated to be far lower than the licensing criteria. It is therefore considered that the proposed double flat core HCLWR is feasible from the point of thermal-hydraulics. Since the available data base has certain applicational limit to the very short core as the present double flat core HCLWR, further detailed assessment is required. (author)

  15. Internal coordination between hydraulics and stomatal control in leaves.

    Science.gov (United States)

    Brodribb, Tim J; Jordan, Gregory J

    2008-11-01

    The stomatal response to changing leaf-atmospheric vapour pressure gradient (D(l)) is a crucial yet enigmatic process that defines the daily course of leaf gas exchange. Changes in the hydration of epidermal cells are thought to drive this response, mediated by the transpiration rate and hydraulic conductance of the leaf. Here, we examine whether species-specific variation in the sensitivity of leaves to perturbation of D(l) is related to the efficiency of water transport in the leaf (leaf hydraulic conductivity, K(leaf)). We found good correlation between maximum liquid (K(leaf)) and gas phase conductances (g(max)) in leaves, but there was no direct correlation between normalized D(l) sensitivity and K(leaf). The impact of K(leaf) on D(l) sensitivity in our diverse sample of eight species was important only after accounting for the strong relationship between K(leaf) and g(max). Thus, the ratio of g(max)/K(leaf) was strongly correlated with stomatal sensitivity to D(l). This ratio is an index of the degree of hydraulic buffering of the stomata against changes in D(l), and species with high g(max) relative to K(leaf) were the most sensitive to D(l) perturbation. Despite the potentially high adaptive significance of this phenomenon, we found no significant phylogenetic or ecological trend in our species.

  16. Dynamic force profile in hydraulic hybrid vehicles: a numerical investigation

    Science.gov (United States)

    Mohaghegh-Motlagh, Amin; Elahinia, Mohammad H.

    2010-04-01

    A hybrid hydraulic vehicle (HHV) combines a hydraulic sub-system with the conventional drivetrain in order to improve fuel economy for heavy vehicles. The added hydraulic module manages the storage and release of fluid power necessary to assist the motion of the vehicle. The power collected by a pump/motor (P/M) from the regenerative braking phase is stored in a high-pressure accumulator and then released by the P/M to the driveshaft during the acceleration phase. This technology is effective in significantly improving fuel-economy for heavy-class vehicles with frequent stop-and-go drive schedules. Despite improved fuel economy and higher vehicle acceleration, noise and vibrations are one of the main problems of these vehicles. The dual function P/Ms are the main source of noise and vibration in a HHV. This study investigates the dynamics of a P/M and particularly the profile and frequency-dependence of the dynamic forces generated by a bent-axis P/M unit. To this end, the fluid dynamics side of the problem has been simplified for investigating the system from a dynamics perspective. A mathematical model of a bent axis P/M has been developed to investigate the cause of vibration and noise in HHVs. The forces are calculated in time and frequency domains. The results of this work can be used to study the vibration response of the chassis and to design effective vibration isolation systems for HHVs.

  17. Hydraulic impact end effector final test report. Automation and robotics section, ER/WM-AT Program

    International Nuclear Information System (INIS)

    Couture, S.

    1994-01-01

    One tool being developed for dislodging and fragmenting the hard salt cake waste in the single-shell nuclear waste tanks at the Hanford Reservation near Richland, Washington, is the hydraulic impact end effector (HIEE). This total operates by discharging 11-in. slugs of water at ultrahigh pressures. The HIEE was designed, built, and initially tested in 1992. Work in 1993 included advanced developments of the HIEE to further investigate its fragmentation abilities and to determine more effective operating procedures. These tests showed that more fragmentation can be achieved by increasing the charge pressure of 40 kpsi to 55 kpsi and by the use of different operating procedures. The size of the material and the impact energy of the water slug fired from the HIEE are believed to be major factors in material fragmentation. The material's ability to fracture also appears to depend on the distance a fracture or crack line must travel to a free surface. Thus, larger material is more difficult to fracture than smaller material. Discharge pressures of 40 kpsi resulted in little penetration or fracturing of the material. At 55 kpsi, however, the size and depth of the fractures increased. Nozzle geometry had a significant effect on fragment size and quantity. Fragmentation was about an order of magnitude greater when the HIEE was discharged into drilled holes rather than onto the material surface. Since surface shots tend to create craters, a multi-shot procedure, coupled with an advanced nozzle design, was used to drill (crater) deep holes into large material. With this procedure, a 600-lb block was reduced to smaller pieces without the use of any additional equipment. Through this advanced development program, the HIEE has demonstrated that it can quickly fragment salt cake material into small, easily removable fragments. The HIEE's material fragmentation ability can be substantially increased through the use of different nozzle geometries and operating procedures

  18. Design of Pumps for Water Hydraulic Systems

    DEFF Research Database (Denmark)

    Klit, Peder; Olsen, Stefan; Bech, Thomas Nørgaard

    1999-01-01

    This paper considers the development of two pumps for water hydraulic applications. The pumps are based on two different working principles: The Vane-type pump and the Gear-type pump. Emphasis is put on the considerations that should be made to account for water as the hydraulic fluid.......KEYWORDS: water, pump, design, vane, gear....

  19. Uncertainty in hydraulic tests in fractured rock

    International Nuclear Information System (INIS)

    Ji, Sung-Hoon; Koh, Yong-Kwon

    2014-01-01

    Interpretation of hydraulic tests in fractured rock has uncertainty because of the different hydraulic properties of a fractured rock to a porous medium. In this study, we reviewed several interesting phenomena which show uncertainty in a hydraulic test at a fractured rock and discussed their origins and the how they should be considered during site characterisation. Our results show that the estimated hydraulic parameters of a fractured rock from a hydraulic test are associated with uncertainty due to the changed aperture and non-linear groundwater flow during the test. Although the magnitude of these two uncertainties is site-dependent, the results suggest that it is recommended to conduct a hydraulic test with a little disturbance from the natural groundwater flow to consider their uncertainty. Other effects reported from laboratory and numerical experiments such as the trapping zone effect (Boutt, 2006) and the slip condition effect (Lee, 2014) can also introduce uncertainty to a hydraulic test, which should be evaluated in a field test. It is necessary to consider the way how to evaluate the uncertainty in the hydraulic property during the site characterisation and how to apply it to the safety assessment of a subsurface repository. (authors)

  20. Hydraulically powered dissimilar teleoperated system controller design

    International Nuclear Information System (INIS)

    Jansen, J.F.; Kress, R.L.

    1996-01-01

    This paper will address two issues associated with the implementation of a hydraulically powered dissimilar master-slave teleoperated system. These issues are the overall system control architecture and the design of robust hydraulic servo controllers for the position control problem. Finally, a discussion of overall system performance on an actual teleoperated system will be presented

  1. Analysis of the steady state hydraulic behaviour of the ITER blanket cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Di Maio, P.A., E-mail: pietroalessandro.dimaio@unipa.it [Dipartimento di Energia, Ingegneria dell’Informazione e Modelli Matematici, Università di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Dell’Orco, G.; Furmanek, A. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Garitta, S. [Dipartimento di Energia, Ingegneria dell’Informazione e Modelli Matematici, Università di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Merola, M.; Mitteau, R.; Raffray, R. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Spagnuolo, G.A.; Vallone, E. [Dipartimento di Energia, Ingegneria dell’Informazione e Modelli Matematici, Università di Palermo, Viale delle Scienze, 90128 Palermo (Italy)

    2015-10-15

    Highlights: • Nominal steady state hydraulic behaviour of ITER blanket standard sector cooling system has been investigated. • Numerical simulations have been run adopting a qualified thermal-hydraulic system code. • Hydraulic characteristic functions and coolant mass flow rates, velocities and pressure drops have been assessed. • Most of the considered circuits are able to effectively cool blanket modules, meeting ITER requirements. - Abstract: The blanket system is the ITER reactor component devoted to providing a physical boundary for plasma transients and contributing to thermal and nuclear shielding of vacuum vessel, magnets and external components. It is expected to be subjected to significant heat loads under nominal conditions and its cooling system has to ensure an adequate cooling, preventing any risk of critical heat flux occurrence while complying with pressure drop limits. At the University of Palermo a study has been performed, in cooperation with the ITER Organization, to investigate the steady state hydraulic behaviour of the ITER blanket standard sector cooling system. A theoretical–computational approach based on the finite volume method has been followed, adopting the RELAP5 system code. Finite volume models of the most critical blanket cooling circuits have been set-up, realistically simulating the coolant flow domain. The steady state hydraulic behaviour of each cooling circuit has been investigated, determining its hydraulic characteristic function and assessing the spatial distribution of coolant mass flow rates, velocities and pressure drops under reference nominal conditions. Results obtained have indicated that the investigated cooling circuits are able to provide an effective cooling to blanket modules, generally meeting ITER requirements in term of pressure drop and velocity distribution, except for a couple of circuits that are being revised.

  2. On-Shore Central Hydraulic Power Generation for Wind and Tidal Energy

    Science.gov (United States)

    Jones, Jack A.; Bruce, Allan; Lim, Steven; Murray, Luke; Armstrong, Richard; Kimbrall, Richard; Cook-Chenault, Kimberly; DeGennaro, Sean

    2012-01-01

    Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by means of converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central power plant, and the low-pressure outlet flow is returned. The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kW tidal hydraulic power generation system in the laboratory and possibly later submerged in the ocean. All gears and submerged electronics are completely eliminated. A second portion of this DOE project involves sizing and costing a 15 MW tidal energy system for a commercial tidal energy plant. For this task, Atlantis Resources Corporation s 18-m diameter demonstrated tidal blades are rated to operate in a nominal 2.6 m/sec tidal flow to produce approximately one MW per set of tidal blades. Fifteen units would be submerged in a deep tidal area, such as in Maine s Western Passage. All would be connected to a high-pressure (20 MPa, 2900 psi) line that is 35 cm ID. The high-pressure HEPG fluid flow is transported 500-m to on-shore hydraulic generators. HEPG is an environmentally-friendly, biodegradable, watermiscible fluid. Hydraulic adaptations to ORPC s cross-flow turbines are also discussed. For 15 MW of wind energy that is onshore or offshore, a gearless, high efficiency, radial piston pump can replace each set of top-mounted gear-generators. The fluid is then pumped to a central, easily serviceable generator location. Total hydraulic/electrical efficiency is 0.81 at full rated wind or tidal velocities and increases to 0.86 at 1/3 rated velocities.

  3. Hydraulic loop: practices using open control systems

    International Nuclear Information System (INIS)

    Carrasco, J.A.; Alonso, L.; Sanchez, F.

    1998-01-01

    The Tecnatom Hydraulic Loop is a dynamic training platform. It has been designed with the purpose of improving the work in teams. With this system, the student can obtain a full scope vision of a system. The hydraulic Loop is a part of the Tecnatom Maintenance Centre. The first objective of the hydraulic Loop is the instruction in components, process and process control using open control system. All the personal of an electric power plant can be trained in the Hydraulic Loop with specific courses. The development of a dynamic tool for tests previous to plant installations has been an additional objective of the Hydraulic Loop. The use of this platform is complementary to the use of full-scope simulators in order to debug and to analyse advanced control strategies. (Author)

  4. Hydraulic jumps in a channel

    DEFF Research Database (Denmark)

    Bonn, D.; Andersen, Anders Peter; Bohr, Tomas

    2009-01-01

    We present a study of hydraulic jumps with flow predominantly in one direction, created either by confining the flow to a narrow channel with parallel walls or by providing an inflow in the form of a narrow sheet. In the channel flow, we find a linear height profile upstream of the jump as expected......'s mixing-length theory with a mixing length that is proportional to the height of the fluid layer. Using averaged boundary-layer equations, taking into account the friction with the channel walls and the eddy viscosity, the flow both upstream and downstream of the jump can be understood. For the downstream...... subcritical flow, we assume that the critical height is attained close to the channel outlet. We use mass and momentum conservation to determine the position of the jump and obtain an estimate which is in rough agreement with our experiment. We show that the averaging method with a varying velocity profile...

  5. On hydraulics of capillary tubes

    Directory of Open Access Journals (Sweden)

    N.G. Aloyan

    2016-03-01

    Full Text Available The article considers the laws of motion of water in the capillary tubes, taken as a model for flowing well, on the analogical net count device. For capillary tube the lower limit value of flow rate is empirically determined above which the total hydraulic resistance of the capillary is practically constant. The specificity of the phenomenon is that the regime of motion, by a Reynolds number, for a given flow rate still remains laminar. This circumstance can perplex the specialists, so the author invites them to the scientific debate on the subject of study. Obviously, to identify the resulting puzzle it is necessary to conduct a series of experiments using capillaries of different lengths and diameters and with different values of overpressure. The article states that in tubes with very small diameter the preliminary magnitude of capillary rise of water in the presence of flow plays no role and can be neglected.

  6. HANARO thermal hydraulic accident analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chul; Kim, Heon Il; Lee, Bo Yook; Lee, Sang Yong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-06-01

    For the safety assessment of HANARO, accident analyses for the anticipated operational transients, accident scenarios and limiting accident scenarios were conducted. To do this, the commercial nuclear reactor system code. RELAP5/MOD2 was modified to RELAP5/KMRR; the thermal hydraulic correlations and the heat exchanger model was changed to incorporate HANARO characteristics. This report summarizes the RELAP/KMRR calculation results and the subchannel analyses results based on the RELAP/KMRR results. During the calculation, major concern was placed on the integrity of the fuel. For all the scenarios, the important accident analysis parameters, i.e., fuel centerline temperatures and the minimum critical heat flux ratio(MCHFR), satisfied safe design limits. It was verified, therefore, that the HANARO was safely designed. 21 tabs., 89 figs., 39 refs. (Author) .new.

  7. Hydraulically amplified PZT mems actuator

    Science.gov (United States)

    Miles, Robin R.

    2004-11-02

    A hydraulically amplified microelectromechanical systems actuator. A piece of piezoelectric material or stacked piezo bimorph is bonded or deposited as a thin film. The piece is operatively connected to a primary membrane. A reservoir is operatively connected to the primary membrane. The reservoir contains a fluid. A membrane is operatively connected to the reservoir. In operation, energizing the piezoelectric material causing the piezoelectric material to bow. Bowing of the piezoelectric material causes movement of the primary membrane. Movement of the primary membrane results in a force in being transmitted to the liquid in the reservoir. The force in the liquid causes movement of the membrane. Movement of the membrane results in an operating actuator.

  8. Dolomitic lime containing hydraulic additive

    International Nuclear Information System (INIS)

    Lagzdina, S.; Sedmalis, U.; Bidermanis, L.; Liepins, J.; Grosvalds, I.

    1997-01-01

    To obtain qualitative dolomitic lime the optimum calcination temperature of dolomite containing about 9 % of clayey substances is 900 deg C. The mechanical strength of dolomitic lime containing 30 % of brick waste additive after 6-9 months of hardening is 1.4-1.5 times higher than that of samples without hydraulic additive, for calcium lime - 2.2-2.6 times higher. Generally the mechanical strength of dolomitic lime is higher than that one of calcium lime. It can be explained by the active role of MgO in the hydration and hardening processes of dolomitic lime. Xray diffraction phase analysis was performed by X-ray diffractometer DPON-3M with Cu-K α emission filter

  9. effective hydraulic conductivity for a soil of variable pore size

    African Journals Online (AJOL)

    eobe

    Keywords: hydraulic conductivity, soil, infiltration, permeability, water. 1. INTRODUCTION. INTRODUCTION. INTRODUCTION. Accurate determination of hydraulic conductivity is very crucial for infiltration and runoff estimation. Factors which affect water infiltration in the soil include hydraulic conductivity, wetting front and soil.

  10. A Hydraulic Motor-Alternator System for Ocean-Submersible Vehicles

    Science.gov (United States)

    Aintablian, Harry O.; Valdez, Thomas I.; Jones, Jack A.

    2012-01-01

    An ocean-submersible vehicle has been developed at JPL that moves back and forth between sea level and a depth of a few hundred meters. A liquid volumetric change at a pressure of 70 bars is created by means of thermal phase change. During vehicle ascent, the phase-change material (PCM) is melted by the circulation of warm water and thus pressure is increased. During vehicle descent, the PCM is cooled resulting in reduced pressure. This pressure change is used to generate electric power by means of a hydraulic pump that drives a permanent magnet (PM) alternator. The output energy of the alternator is stored in a rechargeable battery that powers an on-board computer, instrumentation and other peripherals.The focus of this paper is the performance evaluation of a specific hydraulic motor-alternator system. Experimental and theoretical efficiency data of the hydraulic motor and the alternator are presented. The results are used to evaluate the optimization of the hydraulic motor-alternator system. The integrated submersible vehicle was successfully operated in the Pacific Ocean near Hawaii. A brief overview of the actual test results is presented.

  11. Hydraulic activities by ghost shrimp Neotrypaea californiensis induce oxic-anoxic oscillations in sediments

    Science.gov (United States)

    We applied porewater pressure sensing, time-lapse photography and planar optode imaging of oxygen to investigate hydraulic behaviors of the Thalassinidean ghost shrimp Neotrypaea californiensis and the associated dynamics of oxygen in and around their burrows. Ghost shrimp were h...

  12. Robust Position Tracking for Electro-Hydraulic Drives Based on Generalized Feedforward Compensation Approach

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Andersen, Torben Ole; Pedersen, Henrik C.

    2012-01-01

    This paper presents a robust tracking control concept based on accurate feedforward compensation for hydraulic valve-cylinder drives. The proposed feedforward compensator is obtained utilizing a generalized description of the valve flow that takes into account any asymmetry of valves and...... constant gain type feedforward compensator, when subjected to strong perturbations in supply pressure and coulomb friction....

  13. Model-based servo hydraulic control of a continuously variable transmission

    NARCIS (Netherlands)

    Cools, S.J.M.; Veenhuizen, P.A.; Pauwelussen, J.P.

    2004-01-01

    In order to reduce the power consumption of a transmission, maximum tracking accuracy should be achieved of both ratio and pressures in the variator. A control strategy is proposed to steer a variator, actuated with a newly developed hydraulic system, of a Continuously Variable Transmission (CVT).

  14. Dual hydraulic behaviour of the Chalk in the Netherlands North Sea

    NARCIS (Netherlands)

    Verweij, H.

    2006-01-01

    Information on the sedimentary development, seismic stratigraphy and burial compaction of the Chalk Group in the Netherlands North Sea was combined with pressure data and basin modelling to investigate the hydraulic behaviour of the Chalk Group in the Central Graben and Schill Grund High. The

  15. Modeling and design of cooperative braking in electric and hybrid vehicles using induction machine and hydraulic brake

    Directory of Open Access Journals (Sweden)

    Zaini Dalimus

    2016-07-01

    Full Text Available In mixed-mode braking applications, the electric motor / generator (M/G and hydraulic pressure valve are controlled to meet the driver’s braking demand. Controlling these braking elements is achieved by modulating the current generated by the M/G and adjusting the fluid pressure to the wheel brake cylinders. This paper aims to model and design combined regenerative and hydraulic braking systems which, comprise an induction electric machine, inverter, NiMH battery, controller, a pressure source, pressure control unit, and brake calipers. A 15 kW 1500 rpm induction machine equipped with a reduction gear having a gear ratio of 4 is used. A hydraulic brake capable to produce fluid pressure up to 40 bar is used. Direct torque control and pressure control are chosen as the control criteria in the M/G and the hydraulic solenoid valve. The braking demands for the system are derived from the Federal Testing Procedure (FTP drive cycle. Two simulation models have been developed in Matlab®/Simulink® to analyze the performance of the control strategy in each braking system. The developed model is validated through experiment. It is concluded that the control system does introduce torque ripple and pressure oscillation in the braking system, but these effects do not affect vehicle braking performance due to the high frequency nature of pressure fluctuation and the damping effect of the vehicle inertia. Moreover, experiment results prove the effectiveness of the developed model.

  16. Static Analysis of High-Performance Fixed Fluid Power Drive with a Single Positive-Displacement Hydraulic Motor

    Directory of Open Access Journals (Sweden)

    O. F. Nikitin

    2015-01-01

    Full Text Available The article deals with the static calculations in designing a high-performance fixed fluid power drive with a single positive-displacement hydraulic motor. Designing is aimed at using a drive that is under development and yet unavailable to find and record the minimum of calculations and maximum of existing hydraulic units that enable clear and unambiguous performance, taking into consideration an available assortment of hydraulic units of hydraulic drives, to have the best efficiency.The specified power (power, moment and kinematics (linear velocity or angular velocity of rotation parameters of the output element of hydraulic motor determine the main output parameters of the hydraulic drive and the useful power of the hydraulic drive under development. The value of the overall efficiency of the hydraulic drive enables us to judge the efficiency of high-performance fixed fluid power drive.The energy analysis of a diagram of the high-performance fixed fluid power drive shows that its high efficiency is achieved when the flow rate of fluid flowing into each cylinder and the magnitude of the feed pump unit (pump are as nearly as possible.The paper considers the ways of determining the geometric parameters of working hydromotors (effective working area or working volume, which allow a selection of the pumping unit parameters. It discusses the ways to improve hydraulic drive efficiency. Using the principle of holding constant conductivity allows us to specify the values of the pressure losses in the hydraulic units used in noncatalog modes. In case of no exact matching between the parameters of existing hydraulic power modes and a proposed characteristics of the pump unit, the nearest to the expected characteristics is taken as a working version.All of the steps allow us to create the high-performance fixed fluid power drive capable of operating at the required power and kinematic parameters with high efficiency.

  17. Nonlinear adaptive robust back stepping force control of hydraulic load simulator: Theory and experiments

    International Nuclear Information System (INIS)

    Yao, Jianyong; Jiao, Zongxia; Yao, Bin

    2014-01-01

    High performance robust force control of hydraulic load simulator with constant but unknown hydraulic parameters is considered. In contrast to the linear control based on hydraulic linearization equations, hydraulic inherent nonlinear properties and uncertainties make the conventional feedback proportional-integral-derivative (PID) control not yield to high performance requirements. Furthermore, the hydraulic system may be subjected to non-smooth and discontinuous nonlinearities due to the directional change of valve opening. In this paper, based on a nonlinear system model of hydraulic load simulator, a discontinuous projection-based nonlinear adaptive robust back stepping controller is developed with servo valve dynamics. The proposed controller constructs a novel stable adaptive controller and adaptation laws with additional pressure dynamic related unknown parameters, which can compensate for the system nonlinearities and uncertain parameters, meanwhile a well-designed robust controller is also synthesized to dominate the model uncertainties coming from both parametric uncertainties and uncertain nonlinearities including unmodeled and ignored system dynamics. The controller theoretically guarantee a prescribed transient performance and final tracking accuracy in presence of both parametric uncertainties and uncertain nonlinearities; while achieving asymptotic output tracking in the absence of unstructured uncertainties. The implementation issues are also discussed for controller simplification. Some comparative results are obtained to verify the high-performance nature of the proposed controller.

  18. Synthetical optimization of hydraulic radius and acoustic field for thermoacoustic cooler

    International Nuclear Information System (INIS)

    Kang Huifang; Li Qing; Zhou Gang

    2009-01-01

    It is well known that the acoustic field and the hydraulic radius of the regenerator play key roles in thermoacoustic processes. The optimization of hydraulic radius strongly depends on the acoustic field in the regenerator. This paper investigates the synthetical optimization of hydraulic radius and acoustic field which is characterized by the ratio of the traveling wave component to the standing wave component. In this paper, we discussed the heat flux, cooling power, temperature gradient and coefficient of performance of thermoacoustic cooler with different combinations of hydraulic radiuses and acoustic fields. The calculation results show that, in the cooler's regenerator, due to the acoustic wave, the heat is transferred towards the pressure antinodes in the pure standing wave, while the heat is transferred in the opposite direction of the wave propagation in the pure traveling wave. The better working condition for the regenerator appears in the traveling wave phase region of the like-standing wave, where the directions of the heat transfer by traveling wave component and standing wave component are the same. Otherwise, the small hydraulic radius is not a good choice for acoustic field with excessively high ratio of traveling wave, and the small hydraulic radius is only needed by the traveling wave phase region of like-standing wave.

  19. Network hydraulics inclusion in water quality event detection using multiple sensor stations data.

    Science.gov (United States)

    Oliker, Nurit; Ostfeld, Avi

    2015-09-01

    Event detection is one of the current most challenging topics in water distribution systems analysis: how regular on-line hydraulic (e.g., pressure, flow) and water quality (e.g., pH, residual chlorine, turbidity) measurements at different network locations can be efficiently utilized to detect water quality contamination events. This study describes an integrated event detection model which combines multiple sensor stations data with network hydraulics. To date event detection modelling is likely limited to single sensor station location and dataset. Single sensor station models are detached from network hydraulics insights and as a result might be significantly exposed to false positive alarms. This work is aimed at decreasing this limitation through integrating local and spatial hydraulic data understanding into an event detection model. The spatial analysis complements the local event detection effort through discovering events with lower signatures by exploring the sensors mutual hydraulic influences. The unique contribution of this study is in incorporating hydraulic simulation information into the overall event detection process of spatially distributed sensors. The methodology is demonstrated on two example applications using base runs and sensitivity analyses. Results show a clear advantage of the suggested model over single-sensor event detection schemes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Nonlinear adaptive robust back stepping force control of hydraulic load simulator: Theory and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Jianyong [Nanjing University of Science and Technology, Nanjing (China); Jiao, Zongxia [Beihang University, Beijing (China); Yao, Bin [Purdue University, West Lafayette (United States)

    2014-04-15

    High performance robust force control of hydraulic load simulator with constant but unknown hydraulic parameters is considered. In contrast to the linear control based on hydraulic linearization equations, hydraulic inherent nonlinear properties and uncertainties make the conventional feedback proportional-integral-derivative (PID) control not yield to high performance requirements. Furthermore, the hydraulic system may be subjected to non-smooth and discontinuous nonlinearities due to the directional change of valve opening. In this paper, based on a nonlinear system model of hydraulic load simulator, a discontinuous projection-based nonlinear adaptive robust back stepping controller is developed with servo valve dynamics. The proposed controller constructs a novel stable adaptive controller and adaptation laws with additional pressure dynamic related unknown parameters, which can compensate for the system nonlinearities and uncertain parameters, meanwhile a well-designed robust controller is also synthesized to dominate the model uncertainties coming from both parametric uncertainties and uncertain nonlinearities including unmodeled and ignored system dynamics. The controller theoretically guarantee a prescribed transient performance and final tracking accuracy in presence of both parametric uncertainties and uncertain nonlinearities; while achieving asymptotic output tracking in the absence of unstructured uncertainties. The implementation issues are also discussed for controller simplification. Some comparative results are obtained to verify the high-performance nature of the proposed controller.

  1. 3D Simulation of Multiple Simultaneous Hydraulic Fractures with Different Initial Lengths in Rock

    Science.gov (United States)

    Tang, X.; Rayudu, N. M.; Singh, G.

    2017-12-01

    Hydraulic fracturing is widely used technique for extracting shale gas. During this process, fractures with various initial lengths are induced in rock mass with hydraulic pressure. Understanding the mechanism of propagation and interaction between these induced hydraulic cracks is critical for optimizing the fracking process. In this work, numerical results are presented for investigating the effect of in-situ parameters and fluid properties on growth and interaction of multi simultaneous hydraulic fractures. A fully coupled 3D fracture simulator, TOUGH- GFEM is used for simulating the effect of different vital parameters, including in-situ stress, initial fracture length, fracture spacing, fluid viscosity and flow rate on induced hydraulic fractures growth. This TOUGH-GFEM simulator is based on 3D finite volume method (FVM) and partition of unity element method (PUM). Displacement correlation method (DCM) is used for calculating multi - mode (Mode I, II, III) stress intensity factors. Maximum principal stress criteria is used for crack propagation. Key words: hydraulic fracturing, TOUGH, partition of unity element method , displacement correlation method, 3D fracturing simulator

  2. Hydraulic and thermal design of a gas microchannel heat exchanger

    International Nuclear Information System (INIS)

    Yang Yahui; Brandner, Juergen J; Morini, Gian Luca

    2012-01-01

    In this paper investigations on the design of a gas flow microchannel heat exchanger are described in terms of hydrodynamic and thermal aspects. The optimal choice for thermal conductivity of the solid material is discussed by analysis of its influences on the thermal performance of a micro heat exchanger. Two numerical models are built by means of a commercial CFD code (Fluent). The simulation results provide the distribution of mass flow rate, inlet pressure and pressure loss, outlet pressure and pressure loss, subjected to various feeding pressure values. Based on the thermal and hydrodynamic analysis, a micro heat exchanger made of polymer (PEEK) is designed and manufactured for flow and heat transfer measurements in air flows. Sensors are integrated into the micro heat exchanger in order to measure the local pressure and temperature in an accurate way. Finally, combined with numerical simulation, an operating range is suggested for the present micro heat exchanger in order to guarantee uniform flow distribution and best thermal and hydraulic performances.

  3. Spatial variability of soil hydraulic properties on a steep slope in the loess plateau of China Variabilidade espacial de propriedades hídricas do solo de uma encosta do "Loess Plateau" da China

    Directory of Open Access Journals (Sweden)

    Wei Hu

    2008-01-01

    Full Text Available The understanding of the structure of the spatial variability of soil surface hydraulic properties on steep slopes is important for modeling infiltration and runoff processes. The objective of this study was to investigate the spatial variability of these properties on a steep slope of the Loess Plateau in northwest China. A 9600 m² area was systematically sampled in a grid of 106 points spaced 10 m x 10 m. Hydraulic properties were determined with a disc infiltrometer under multiple pressure heads (-15, -9, -6, -3, 0 cm at each sample point. Classical and geo-statistical methods were used for data analysis. The results indicated that the variation of Gardner's a and hydraulic conductivities at all applied pressure heads was moderate and the heterogeneity for hydraulic conductivities increased as the applied pressure head increased. Along the slope, hydraulic conductivities generally decreased downwards, while the Gardner's a fluctuated slightly. The Gardner's a of the shaded aspect of the slope was greater than that of the sunny aspect. The hydraulic conductivities of the shaded aspect were greater at higher pressure heads as compared to the sunny aspect, but lower than those of the sunny aspect at lower pressure heads. Correlation analysis showed a negative correlation between hydraulic conductivity and soil organic matter and clay (A compreensão da estrutura da variabilidade especial das propriedades hidráulicas do solo de encostas íngremes é importante na modelagem dos processos de infiltração e de escoamento superficial da água. O objetivo deste estudo foi investigar a variabilidade destas propriedades em uma encosta íngreme do "Loess Plateau" do noroeste da China. Uma área de 9600 m² foi sistematicamente amostrada em um grid de 106 pontos espaçados de 10 m x 10 m. As propriedades hídricas foram determinadas com um infiltrômetro de disco operando sob múltiplas cargas hidráulicas (-15, -9, -6, -3, 0 cm em cada ponto de

  4. Greater trochanteric pain syndrome diagnosis and treatment.

    Science.gov (United States)

    Mallow, Michael; Nazarian, Levon N

    2014-05-01

    Lateral hip pain, or greater trochanteric pain syndrome, is a commonly seen condition; in this article, the relevant anatomy, epidemiology, and evaluation strategies of greater trochanteric pain syndrome are reviewed. Specific attention is focused on imaging of this syndrome and treatment techniques, including ultrasound-guided interventions. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Hydraulic mechanism and time-dependent characteristics of loose gully deposits failure induced by rainfall

    Directory of Open Access Journals (Sweden)

    Yong Wu

    2015-12-01

    Full Text Available Failure of loose gully deposits under the effect of rainfall contributes to the potential risk of debris flow. In the past decades, researches on hydraulic mechanism and time-dependent characteristics of loose deposits failure are frequently reported, however adequate measures for reducing debris flow are not available practically. In this context, a time-dependent model was established to determine the changes of water table of loose deposits using hydraulic and topographic theories. In addition, the variation in water table with elapsed time was analyzed. The formulas for calculating hydrodynamic and hydrostatic pressures on each strip and block unit of deposit were proposed, and the slope stability and failure risk of the loose deposits were assessed based on the time-dependent hydraulic characteristics of established model. Finally, the failure mechanism of deposits based on infinite slope theory was illustrated, with an example, to calculate sliding force, anti-sliding force and residual sliding force applied to each slice. The results indicate that failure of gully deposits under the effect of rainfall is the result of continuously increasing hydraulic pressure and water table. The time-dependent characteristics of loose deposit failure are determined by the factors of hydraulic properties, drainage area of interest, rainfall pattern, rainfall duration and intensity.

  6. Parameters Analysis of Hydraulic-Electrical Energy Regenerative Absorber on Suspension Performance

    Directory of Open Access Journals (Sweden)

    Han Zhang

    2014-05-01

    Full Text Available To recycle the vibration energy of vehicles over rough roads, a hydraulic-electricity energy regenerative suspension (HEERS was designed in the present work, and simulations were performed with focus on its performance. On the basis of the system principle, the mathematical model of hydraulic-electrical energy regenerative absorber (HEERA and two degrees of freedom (DOF suspension dynamic model were constructed. Using the model of HEERA, simulations on force-displacement and force-velocity characteristics were performed with a 1.67 Hz frequency and a sinusoidal input adopted. And then in combination with HEERA model and two DOF suspension models, simulations on the performance of HEERS also were carried out. Finally, the influences of charging pressure and volume of the accumulator, hydraulic motor displacement, orifice area of check valve, and inner diameter of hydraulic pipelines on the performance of HEERA and HEERS were investigated in depth. The simulation results indicated that (i the damping characteristic of HEERA was coincident with the damping characteristics of traditional absorber; (ii the most remarkable influencing factor on the performance of HEERS was the hydraulic motor displacement, followed by orifice area of check valve, inner diameter of pipelines, and charging pressure of accumulator, while the effects of charging volume of accumulator were quite limited.

  7. Experimental evaluation of the hydraulic resistance of compacted bentonite/boom clay interface

    International Nuclear Information System (INIS)

    Tang, Anh-Minh; Cui, Yu-Jun; Delage, Pierre; Munoz, Juan Jorge; Li, Xiang-Ling

    2008-01-01

    In the framework of the in-situ PRACLAY Heater experiment to be performed in the HADES URF in Mol (Belgium), the feasibility of a hydraulic cut-off of the Excavation Damaged Zone (EDZ) and the Repository Components (RC) of the disposal galleries by using a horizontal seal will be examined. It has been planned to install an annular seal composed of compacted bentonite between the heated zone and the access gallery (PRACLAY seal test), so that to avoid any hydraulic shortcut towards the access gallery. According to numerical scoping calculations, heating until 80 deg C will induce a pore pressure of the order of 3.0 MPa. In order to verify the effects of this water pressure on the performance of the annular seal system and more specifically on the hydraulic resistance of the interface between the compacted bentonite and the host rock (Boom clay), laboratory percolation tests at 20 and 80 deg C were performed. The results confirm the performance of the compacted bentonite seal to avoid the hydraulic shortcut to the access gallery under the foreseen hydraulic and thermal conditions. (author)

  8. Fault diagnosis of an intelligent hydraulic pump based on a nonlinear unknown input observer

    Directory of Open Access Journals (Sweden)

    Zhonghai MA

    2018-02-01

    Full Text Available Hydraulic piston pumps are commonly used in aircraft. In order to improve the viability of aircraft and energy efficiency, intelligent variable pressure pump systems have been used in aircraft hydraulic systems more and more widely. Efficient fault diagnosis plays an important role in improving the reliability and performance of hydraulic systems. In this paper, a fault diagnosis method of an intelligent hydraulic pump system (IHPS based on a nonlinear unknown input observer (NUIO is proposed. Different from factors of a full-order Luenberger-type unknown input observer, nonlinear factors of the IHPS are considered in the NUIO. Firstly, a new type of intelligent pump is presented, the mathematical model of which is established to describe the IHPS. Taking into account the real-time requirements of the IHPS and the special structure of the pump, the mechanism of the intelligent pump and failure modes are analyzed and two typical failure modes are obtained. Furthermore, a NUIO of the IHPS is performed based on the output pressure and swashplate angle signals. With the residual error signals produced by the NUIO, online intelligent pump failure occurring in real-time can be detected. Lastly, through analysis and simulation, it is confirmed that this diagnostic method could accurately diagnose and isolate those typical failure modes of the nonlinear IHPS. The method proposed in this paper is of great significance in improving the reliability of the IHPS. Keywords: Fault diagnosis, Hydraulic piston pump, Model-based, Nonlinear unknown input observer (NUIO, Residual error

  9. Highly-Integrated Hydraulic Smart Actuators and Smart Manifolds for High-Bandwidth Force Control

    Directory of Open Access Journals (Sweden)

    Victor Barasuol

    2018-06-01

    Full Text Available Hydraulic actuation is the most widely used alternative to electric motors for legged robots and manipulators. It is often selected for its high power density, robustness and high-bandwidth control performance that allows the implementation of force/impedance control. Force control is crucial for robots that are in contact with the environment, since it enables the implementation of active impedance and whole body control that can lead to a better performance in known and unknown environments. This paper presents the hydraulic Integrated Smart Actuator (ISA developed by Moog in collaboration with IIT, as well as smart manifolds for rotary hydraulic actuators. The ISA consists of an additive-manufactured body containing a hydraulic cylinder, servo valve, pressure/position/load/temperature sensing, overload protection and electronics for control and communication. The ISA v2 and ISA v5 have been specifically designed to fit into the legs of IIT’s hydraulic quadruped robots HyQ and HyQ-REAL, respectively. The key features of these components tackle 3 of today’s main challenges of hydraulic actuation for legged robots through: (1 built-in controllers running inside integrated electronics for high-performance control, (2 low-leakage servo valves for reduced energy losses, and (3 compactness thanks to metal additive manufacturing. The main contributions of this paper are the derivation of the representative dynamic models of these highly integrated hydraulic servo actuators, a control architecture that allows for high-bandwidth force control and their experimental validation with application-specific trajectories and tests. We believe that this is the first work that presents additive-manufactured, highly integrated hydraulic smart actuators for robotics.

  10. Insight into the hydraulics and resilience of Ponderosa pine seedlings using a mechanistic ecohydrologic model

    Science.gov (United States)

    Maneta, M. P.; Simeone, C.; Dobrowski, S.; Holden, Z.; Sapes, G.; Sala, A.; Begueria, S.

    2017-12-01

    In semiarid regions, drought-induced seedling mortality is considered to be caused by failure in the tree hydraulic column. Understanding the mechanisms that cause hydraulic failure and death in seedlings is important, among other things, to diagnose where some tree species may fail to regenerate, triggering demographic imbalances in the forest that could result in climate-driven shifts of tree species. Ponderosa pine is a common lower tree line species in the western US. Seedlings of ponderosa pine are often subject to low soil water potentials, which require lower water potentials in the xylem and leaves to maintain the negative pressure gradient that drives water upward. The resilience of the hydraulic column to hydraulic tension is species dependent, but from greenhouse experiments, we have identified general tension thresholds beyond which loss of xylem conductivity becomes critical, and mortality in Ponderosa pine seedlings start to occur. We describe this hydraulic behavior of plants using a mechanistic soil-vegetation-atmosphere transfer model. Before we use this models to understand water-stress induced seedling mortality at the landscape scale, we perform a modeling analysis of the dynamics of soil moisture, transpiration, leaf water potential and loss of plant water conductivity using detailed data from our green house experiments. The analysis is done using a spatially distributed model that simulates water fluxes, energy exchanges and water potentials in the soil-vegetation-atmosphere continuum. Plant hydraulic and physiological parameters of this model were calibrated using Monte Carlo methods against information on soil moisture, soil hydraulic potential, transpiration, leaf water potential and percent loss of conductivity in the xylem. This analysis permits us to construct a full portrait of the parameter space for Ponderosa pine seedling and generate posterior predictive distributions of tree response to understand the sensitivity of transpiration

  11. Investigation on the effect of seawater to hydraulic property and wetting process of bentonite

    International Nuclear Information System (INIS)

    Hasegawa, Takuma

    2004-01-01

    On high-level waste disposal, bentonite is one of the most promising material for buffer and backfill material. The hydraulic properties and wetting process of bentonite are important not only for barrier performance assessment but also for prediction of waste disposal environment, such as resaturation time and thermal distribution. In Japan, we should consider the effect of seawater for bentonite, because radioactive waste will be disposed of in coastal area and in marine sediment where seawater remained. However, it is not enough to understand the effect of seawater. Therefore, experimental study was conducted to investigate the effect of seawater on the hydraulic conductivity and wetting process of bentonite. The effect of seawater on hydraulic conductivity is significant for Na-bentonite, the hydraulic conductivity of Na-bentonite in seawater is one order to magnitude higher than that in distilled water. On the other hand, the hydraulic conductivity of Ca-bentonite is not influenced by seawater. The hydraulic conductivity of bentonite decreases as effective montmorillonite density increases. The effective montmorillonite density is ratio between the weight of montmorillonite and volume of porosity and montmorillonite. The hydraulic conductivity of bentonite is close related to swelling property since the hydraulic conductivity decrease as the swelling pressure increase. Wetting process of compacted bentonite could be evaluated by diffusion phenomena since infiltration rate and change of saturation rate and represented by diffusion equation. The effect of seawater on water diffusivity is significant for Na-type bentonite with low effective montmorillonite density. Except for that condition, the water diffusivity of bentonite is almost constant and is not influenced by effective montmorillonite density and seawater. (author)

  12. Impacts of bedding directions of shale gas reservoirs on hydraulically induced crack propagation

    Directory of Open Access Journals (Sweden)

    Keming Sun

    2016-03-01

    Full Text Available Shale gas reservoirs are different from conventional ones in terms of their bedding architectures, so their hydraulic fracturing rules are somewhat different. In this paper, shale hydraulic fracturing tests were carried out by using the triaxial hydraulic fracturing test system to identify the effects of natural bedding directions on the crack propagation in the process of hydraulic fracturing. Then, the fracture initiation criterion of hydraulic fracturing was prepared using the extended finite element method. On this basis, a 3D hydraulic fracturing computation model was established for shale gas reservoirs. And finally, a series of studies were performed about the effects of bedding directions on the crack propagation created by hydraulic fracturing in shale reservoirs. It is shown that the propagation rules of hydraulically induced fractures in shale gas reservoirs are jointly controlled by the in-situ stress and the bedding plane architecture and strength, with the bedding direction as the main factor controlling the crack propagation directions. If the normal tensile stress of bedding surface reaches its tensile strength after the fracturing, cracks will propagate along the bedding direction, and otherwise vertical to the minimum in-situ stress direction. With the propagating of cracks along bedding surfaces, the included angle between the bedding normal direction and the minimum in-situ stress direction increases, the fracture initiation and propagation pressures increase and the crack areas decrease. Generally, cracks propagate in the form of non-plane ellipsoids. With the injection of fracturing fluids, crack areas and total formation filtration increase and crack propagation velocity decreases. The test results agree well with the calculated crack propagation rules, which demonstrate the validity of the above-mentioned model.

  13. Hydraulic testing around Room Q: Evaluation of the effects of mining on the hydraulic properties of Salado Evaporites

    International Nuclear Information System (INIS)

    Domski, P.S.; Upton, D.T.; Beauheim, R.L.

    1996-03-01

    Room Q is a 109-m-long cylindrical excavation in the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site. Fifteen boreholes were drilled and instrumented around Room Q so that tests could be conducted to determine the effects of room excavation on the hydraulic properties of the surrounding evaporate rocks. Pressure-buildup and pressure-pulse tests were conducted in all of the boreholes before Room Q was mined. The data sets from only eight of the boreholes are adequate for parameter estimation, and five of those are of poor quality. Constant-pressure flow tests and pressure-buildup tests were conducted after Room Q was mined, producing eleven interpretable data sets, including two of poor quality. Pre-mining transmissivities interpreted from the three good-quality data sets ranged from 1 x 10 -15 to 5 x 10 -14 m 2 /s (permeability-thickness products of 2 x 10 -22 to 9 x 10 -21 m 3 ) for test intervals ranging in length from 0.85 to 1.37 m. Pre-mining average permeabilities, which can be considered representative of undisturbed, far-field conditions, were 6 x 10 -20 and 8 x 10 -20 m 2 for anhydrite, and 3 x 10 -22 m 2 for halite. Post-mining transmissivities interpreted from the good-quality data sets ranged from 1 x 10 -16 to 3 x 10 -13 m 2 /s (permeability-thickness products of 2 x 10 -23 to 5 x 10 -20 m 3 ). Post-mining average permeabilities for anhydrite ranged from 8 x 10 -20 to 1 x 10 -19 m 2 . The changes in hydraulic properties and pore pressures that were observed can be attributed to one or a combination of three processes: stress reduction, changes in pore connectivity, and flow towards Room Q. The effects of the three processes cannot be individually quantified with the available data

  14. Modeling and diagnostic techniques applicable to the analysis of pressure noise in pressurized water reactors and pressure-sensing systems

    International Nuclear Information System (INIS)

    Mullens, J.A.; Thie, J.A.

    1984-01-01

    Pressure noise data from a PWR are interpreted by means of a computer-implemented model. The model's parameters, namely hydraulic impedances and noise sources, are either calculated or deduced from fits to data. Its accuracy is encouraging and raises the possibility of diagnostic assistance for nuclear plant monitoring. A number of specific applications of pressure noise in the primary system of a PWR and in a pressure sensing system are suggested

  15. Seismic characteristics of tensile fracture growth induced by hydraulic fracturing

    Science.gov (United States)

    Eaton, D. W. S.; Van der Baan, M.; Boroumand, N.

    2014-12-01

    Hydraulic fracturing is a process of injecting high-pressure slurry into a rockmass to enhance its permeability. Variants of this process are used for unconventional oil and gas development, engineered geothermal systems and block-cave mining; similar processes occur within volcanic systems. Opening of hydraulic fractures is well documented by mineback trials and tiltmeter monitoring and is a physical requirement to accommodate the volume of injected fluid. Numerous microseismic monitoring investigations acquired in the audio-frequency band are interpreted to show a prevalence of shear-dominated failure mechanisms surrounding the tensile fracture. Moreover, the radiated seismic energy in the audio-frequency band appears to be a miniscule fraction (<< 1%) of the net injected energy, i.e., the integral of the product of fluid pressure and injection rate. We use a simple penny-shaped crack model as a predictive framework to describe seismic characteristics of tensile opening during hydraulic fracturing. This model provides a useful scaling relation that links seismic moment to effective fluid pressure within the crack. Based on downhole recordings corrected for attenuation, a significant fraction of observed microseismic events are characterized by S/P amplitude ratio < 5. Despite the relatively small aperture of the monitoring arrays, which precludes both full moment-tensor analysis and definitive identification of nodal planes or axes, this ratio provides a strong indication that observed microseismic source mechanisms have a component of tensile failure. In addition, we find some instances of periodic spectral notches that can be explained by an opening/closing failure mechanism, in which fracture propagation outpaces fluid velocity within the crack. Finally, aseismic growth of tensile fractures may be indicative of a scenario in which injected energy is consumed to create new fracture surfaces. Taken together, our observations and modeling provide evidence that

  16. Hydraulic efficiency and safety of vascular and non-vascular components in Pinus pinaster leaves.

    Science.gov (United States)

    Charra-Vaskou, Katline; Badel, Eric; Burlett, Régis; Cochard, Hervé; Delzon, Sylvain; Mayr, Stefan

    2012-09-01

    Leaves, the distal section of the soil-plant-atmosphere continuum, exhibit the lowest water potentials in a plant. In contrast to angiosperm leaves, knowledge of the hydraulic architecture of conifer needles is scant. We investigated the hydraulic efficiency and safety of Pinus pinaster needles, comparing different techniques. The xylem hydraulic conductivity (k(s)) and embolism vulnerability (P(50)) of both needle and stem were measured using the cavitron technique. The conductance and vulnerability of whole needles were measured via rehydration kinetics, and Cryo-SEM and 3D X-ray microtomographic observations were used as reference tools to validate physical measurements. The needle xylem of P. pinaster had lower hydraulic efficiency (k(s) = 2.0 × 10(-4) m(2) MPa(-1) s(-1)) and safety (P(50) = - 1.5 MPa) than stem xylem (k(s) = 7.7 × 10(-4) m(2) MPa(-1) s(-1); P(50) = - 3.6 to - 3.2 MPa). P(50) of whole needles (both extra-vascular and vascular pathways) was - 0.5 MPa, suggesting that non-vascular tissues were more vulnerable than the xylem. During dehydration to - 3.5 MPa, collapse and embolism in xylem tracheids, and gap formation in surrounding tissues were observed. However, a discrepancy in hydraulic and acoustic results appeared compared with visualizations, arguing for greater caution with these techniques when applied to needles. Our results indicate that the most distal parts of the water transport pathway are limiting for hydraulics of P. pinaster. Needle tissues exhibit a low hydraulic efficiency and low hydraulic safety, but may also act to buffer short-term water deficits, thus preventing xylem embolism.

  17. Thermal-hydraulic unreliability of passive systems

    International Nuclear Information System (INIS)

    Tzanos, C.P.; Saltos, N.T.

    1995-01-01

    Advanced light water reactor designs like AP600 and the simplified boiling water reactor (SBWR) use passive safety systems for accident prevention and mitigation. Because these systems rely on natural forces for their operation, their unavailability due to hardware failures and human error is significantly smaller than that of active systems. However, the coolant flows predicted to be delivered by these systems can be subject to significant uncertainties, which in turn can lead to a significant uncertainty in the predicted thermal-hydraulic performance of the plant under accident conditions. Because of these uncertainties, there is a probability that an accident sequence for which a best estimate thermal-hydraulic analysis predicts no core damage (success sequence) may actually lead to core damage. For brevity, this probability will be called thermal-hydraulic unreliability. The assessment of this unreliability for all the success sequences requires very expensive computations. Moreover, the computational cost increases drastically as the required thermal-hydraulic reliability increases. The required computational effort can be greatly reduced if a bounding approach can be used that either eliminates the need to compute thermal-hydraulic unreliabilities, or it leads to the analysis of a few bounding sequences for which the required thermal-hydraulic reliability is relatively small. The objective of this paper is to present such an approach and determine the order of magnitude of the thermal-hydraulic unreliabilities that may have to be computed

  18. Effect of soil properties on Hydraulic characteristics under subsurface drip irrigation

    Science.gov (United States)

    Fan, Wangtao; Li, Gang

    2018-02-01

    Subsurface drip irrigation (SDI) is a technique that has a high potential in application because of its high efficiency in water-saving. The hydraulic characteristics of SDI sub-unit pipe network can be affected by soil physical properties as the emitters are buried in soils. The related research, however, is not fully explored. The laboratory tests were carried out in the present study to determine the effects of hydraulic factors including operating pressure, initial soil water content, and bulk density on flow rate and its sensitivity to each hydraulic factor for two types of SDI emitters (PLASSIM emitter and Heping emitter). For this purpose, three soils with contrasting textures (i.e., light sand, silt loam, and light clay) were repacked with two soil bulk density (1.25 and1.40 g cm-3) with two initial soil water content (12% and 18%) in plexiglass columns with 40 cm in diameter and 40 cm in height. Drip emitters were buried at depth of 20 cm to measure the flow rates under seven operating pressures (60, 100, 150, 200, 250, 300, and 370 kPa). We found that the operating pressure was the dominating factor of flow rate of the SDI emitter, and flow rate increased with the increase of operating pressure. The initial soil water content and bulk density also affected the flow rate, and their effects were the most notable in the light sand soil. The sensitivity of flow rate to each hydraulic factor was dependent on soil texture, and followed a descending order of light sand>silt loam>light clay for both types of emitters. Further, the sensitivity of flow rate to each hydraulic factor decreased with the increase of operating pressure, initial soil water content, and bulk density. This study may be used to guide the soil specific-design of SDI emitters for optimal water use and management.

  19. Thermal-hydraulic analysis of SMART steam generator tube rupture using TASS/SMR-S code

    International Nuclear Information System (INIS)

    Kim, Hee-Kyung; Kim, Soo Hyoung; Chung, Young-Jong; Kim, Hyeon-Soo

    2013-01-01

    Highlights: ► The analysis was performed from the viewpoint of primary coolant leakage. ► The thermal hydraulic responses and the maximum leakage have been identified. ► There is no direct release into the atmosphere caused by an SGTR accident. ► SMART safety system works well against an SGTR accident. - Abstract: A steam generator tube rupture (SGTR) accident analysis for SMART was performed using the TASS/SMR-S code. SMART with a rated thermal power of 330 MWt has been developed at the Korea Atomic Energy Research Institute. The TASS/SMR-S code can analyze the thermal hydraulic phenomena of SMART in a full range of reactor operating conditions. An SGTR is one of the most important accidents from a thermal hydraulic and radiological viewpoint. A conservative analysis against a SMART SGTR was performed. The major concern of this analysis is to find the thermal hydraulic responses and maximum leakage amount from a primary to a secondary side caused by an SGTR accident. A sensitivity study searching for the conservative thermal hydraulic conditions, break locations, reactivity and other conditions was performed. The dominant parameters related with the integral leak are the high RCS pressure, low core inlet coolant temperature and low break location of the SG cassette. The largest integral leak comes to 28 tons in the most conservative case during 1 h. But there is no direct release into the atmosphere because the secondary system pressure is maintained with a sufficient margin for the design pressure. All leaks go to the condenser. The analysis results show that the primary and secondary system pressures are maintained below the design pressure and the SMART safety system is working well against an SGTR accident

  20. Role of system characteristics in evolution of pump hydraulic design

    International Nuclear Information System (INIS)

    Walia, Mohinder; Misri, Vijay; Sharma, A.K.; Bapat, C.N.

    1994-01-01

    Primary heat transport (PHT) main circuit provides the means for transferring the heat produced in the fuel by circulating heavy water in the main circuit loop by primary coolant pumps (PCPs). The procurement specification of PCPs for 500 MWe pressurised heavy water reactor (PHWR) was prepared based upon the first order hydraulic analysis of the primary heat transport system and accordingly duty point was fixed. With this specification the manufacturer carried out model testing to arrive at optimum size of the impeller followed by determination of pump characteristics curves using full scale impeller during type testing. The duty point thus obtained was higher than specified necessitating the trimming of impeller. However, in order to make use of available higher duty point from system considerations, the duty point was redefined for production of subsequent pumps within specified tolerances governed by manufacturing limitations. PHT main system sizing (piping and feeders) was carried out based upon pump (delivering maximum flow) characteristics curve. Pressure profiles of PHT system at various operating modes were drawn and corresponding power drawn by motor was calculated. The interfacing of reactor coolant main system with hydraulic characteristics of PCP plays a significant role in establishing the requisite capability and capacity of PHT system in performing its intended functions. Therefore the paper traces the evolution of design parameters for PCP and subsequent generation of pressure profiles commensurate with the changes made in power profile including their impact on feeder sizing. The paper also highlights the scope of interaction between process designer and pump manufacturer in formulating a mutually acceptable and efficient hydraulic performance for PCP. (author). 3 refs., 8 figs., 3 tabs