WorldWideScience

Sample records for hydraulic fluid pressure

  1. 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.

  2. Constant-Pressure Hydraulic Pump

    Science.gov (United States)

    Galloway, C. W.

    1982-01-01

    Constant output pressure in gas-driven hydraulic pump would be assured in new design for gas-to-hydraulic power converter. With a force-multiplying ring attached to gas piston, expanding gas would apply constant force on hydraulic piston even though gas pressure drops. As a result, pressure of hydraulic fluid remains steady, and power output of the pump does not vary.

  3. Hydraulic Pressure during Fluid Flow Regulates Purinergic Signaling and Cytoskeleton Organization of Osteoblasts.

    Science.gov (United States)

    Gardinier, Joseph D; Gangadharan, Vimal; Wang, Liyun; Duncan, Randall L

    2014-06-01

    During physiological activities, osteoblasts experience a variety of mechanical forces that stimulate anabolic responses at the cellular level necessary for the formation of new bone. Previous studies have primarily investigated the osteoblastic response to individual forms of mechanical stimuli. However in this study, we evaluated the response of osteoblasts to two simultaneous, but independently controlled stimuli; fluid flow-induced shear stress (FSS) and static or cyclic hydrostatic pressure (SHP or CHP, respectively). MC3T3-E1 osteoblasts-like cells were subjected to 12dyn/cm(2) FSS along with SHP or CHP of varying magnitudes to determine if pressure enhances the anabolic response of osteoblasts during FSS. For both SHP and CHP, the magnitude of hydraulic pressure that induced the greatest release of ATP during FSS was 15 mmHg. Increasing the hydraulic pressure to 50 mmHg or 100 mmHg during FSS attenuated the ATP release compared to 15 mmHg during FSS. Decreasing the magnitude of pressure during FSS to atmospheric pressure reduced ATP release to that of basal ATP release from static cells and inhibited actin reorganization into stress fibers that normally occurred during FSS with 15 mmHg of pressure. In contrast, translocation of nuclear factor kappa B (NFκB) to the nucleus was independent of the magnitude of hydraulic pressure and was found to be mediated through the activation of phospholipase-C (PLC), but not src kinase. In conclusion, hydraulic pressure during FSS was found to regulate purinergic signaling and actin cytoskeleton reorganization in the osteoblasts in a biphasic manner, while FSS alone appeared to stimulate NFκB translocation. Understanding the effects of hydraulic pressure on the anabolic responses of osteoblasts during FSS may provide much needed insights into the physiologic effects of coupled mechanical stimuli on osteogenesis.

  4. Little pump that could : hydraulic submersible pump tackles low pressure, low fluid volume gas wells

    Energy Technology Data Exchange (ETDEWEB)

    Ross, E.

    2008-03-15

    A new pump designed by Global Energy Services was described. The pump was designed to address problems associated with downhole pumps in coalbed methane (CBM) wells. The hydraulic submersible pump (HSP) was designed to address issues related to artificial lift gas lock and solids. The pump has been installed at 35 CBM wells in western Canada as well as at natural gas wells with low pressures and low rates of water. The HSP technology was designed for use with wells between 0.01 cubic metres and 24 cubic metres per day of water. A single joystick in the surface unit is used to determine the amount of hydraulic oil delivered to the bottomhole pump when then determines the amounts of fluid produced. A 10-slot self-flushing sand screen is used to filter out particles of sand, coal, and cement. The pump also includes a hydraulic flow control valve to control water volumes. The HSP's positive displacement design makes it suitable for use in horizontal and deviated wells. The pump technology is currently being re-designed to handle larger volumes at deeper depths. 2 figs.

  5. 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

  6. Numerical Model of Hydraulic Fracturing Fluid Transport in the Subsurface with Pressure Transient, Density Effects, and Imbibition

    Science.gov (United States)

    Birdsell, D.; Rajaram, H.; Dempsey, D.; Viswanathan, H.

    2014-12-01

    Understanding the transport of hydraulic fracturing (HF) fluid that is injected into the deep subsurface for shale gas extraction is important to ensure that shallow drinking water aquifers are not contaminated from an environmental and public health perspective and to understand formation damage from an oil and gas production perspective. Upward pressure gradients, permeable pathways such as faults or improperly abandoned wellbores, and the density contrast of the HF fluid to the surrounding brine encourages upward HF fluid migration. In contrast, the very low shale permeability and the imbibition of water into partially-saturated shale may sequester much of the HF fluid. Using the Finite Element Heat and Mass Transfer Code (FEHM), single-phase flow and transport simulations are performed to quantify how much HF fluid is removed via the wellbore as flowback and produced water and how much reaches overlying aquifers; imbibition is calculated with a semi-analytical one-dimensional solution and treated as a sink term. The travel time for HF fluid to reach the shallow aquifers is highly dependent on the amount of water imbibed and the suction applied to the well. If imbibition rates and suction are small, the pressure transient due to injection and the density contrast allows rapid upward plume migration at early times. The density contrast diminishes considerably within tens to hundreds of years as mixing occurs. We present estimates of HF fluid migration to shallow aquifers during the first 1,000 years after hydraulic fracturing begins for ranges of subsurface properties.

  7. Complex Fluids and Hydraulic Fracturing.

    Science.gov (United States)

    Barbati, Alexander C; Desroches, Jean; Robisson, Agathe; McKinley, Gareth H

    2016-06-07

    Nearly 70 years old, hydraulic fracturing is a core technique for stimulating hydrocarbon production in a majority of oil and gas reservoirs. Complex fluids are implemented in nearly every step of the fracturing process, most significantly to generate and sustain fractures and transport and distribute proppant particles during and following fluid injection. An extremely wide range of complex fluids are used: naturally occurring polysaccharide and synthetic polymer solutions, aqueous physical and chemical gels, organic gels, micellar surfactant solutions, emulsions, and foams. These fluids are loaded over a wide range of concentrations with particles of varying sizes and aspect ratios and are subjected to extreme mechanical and environmental conditions. We describe the settings of hydraulic fracturing (framed by geology), fracturing mechanics and physics, and the critical role that non-Newtonian fluid dynamics and complex fluids play in the hydraulic fracturing process.

  8. Estimation of the fluid excess pressure of hydraulic fractures in paleo geothermal reservoirs; Abschaetzung des Fluidueberdrucks von hydraulischen Bruechen in palaeogeothermischen Reservoiren

    Energy Technology Data Exchange (ETDEWEB)

    Philipp, Sonja L. [Goettingen Univ. (Germany). Geowissenschaftliches Zentrum

    2011-10-24

    In many geothermal reservoirs to low natural permeabilities have to be enhanced by opening or shearing the existing fractures or by generating artificial hydraulic fractures (reservoir stimulation). Such hydraulic fractures can also occur naturally and will remain in paleo geothermal reservoirs. Using the example of calcite passages in a Jurassic limestone-marl alternations in southwest England the author of the contribution under consideration shows that the fault zones (mainly normal faults) were used as fluid transport pathways for calcium carbonate containing water which was injected as hydraulic fractures in the host rock. Overall, in consensus with isotopic studies it was shown that geothermal waters with relatively local origin were within the sedimentary basin and did not come from great depths. The pore fluid pressure within the limestone beds is not sufficient as a reason for the formation of calcite passages.

  9. 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)

  10. CRITICALITY CURVES FOR PLUTONIUM HYDRAULIC FLUID MIXTURES

    Energy Technology Data Exchange (ETDEWEB)

    WITTEKIND WD

    2007-10-03

    This Calculation Note performs and documents MCNP criticality calculations for plutonium (100% {sup 239}Pu) hydraulic fluid mixtures. Spherical geometry was used for these generalized criticality safety calculations and three geometries of neutron reflection are: {sm_bullet}bare, {sm_bullet}1 inch of hydraulic fluid, or {sm_bullet}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.

  11. Maintaining Optimum Pump Performance with Specially- Formulated Hydraulic Fluids

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper describes a battery of tests, and related results, that were performed under normal and severe conditions designed to demonstrate that hydraulic fluids formulated with Lubrizol' s high quality anti - wear hydraulic fluid technology can stand up to today's increasing demands for longer life and provide excellent performance under higher operating temperatures and pressures.

  12. Bio-based Hydraulic Fluids

    Science.gov (United States)

    2008-04-17

    currently formulated with vegetable oils (i.e., rapeseed , sun flower, corn, soybean, canola, coconut, etc.) and synthetic ester, such as polyol ester...2008 Vegetable Oil • Excellent lubrication • Nontoxic • Biodegradable • Derived from renewable resources such as rapeseed , sunflower, corn...Mineral Oil 100 SAE 15W-40 G Rapeseed 32 Commercial HF H Polyol ester 22 MIL-PRF-32073 Grade 2 I Canola - Cooking Oil *Hydraulic fluid 3717 April

  13. 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

  14. Hydraulic fracturing chemicals and fluids technology

    CERN Document Server

    Fink, Johannes

    2013-01-01

    When classifying fracturing fluids and their additives, it is important that production, operation, and completion engineers understand which chemical should be utilized in different well environments. A user's guide to the many chemicals and chemical additives used in hydraulic fracturing operations, Hydraulic Fracturing Chemicals and Fluids Technology provides an easy-to-use manual to create fluid formulations that will meet project-specific needs while protecting the environment and the life of the well. Fink creates a concise and comprehensive reference that enables the engineer to logically select and use the appropriate chemicals on any hydraulic fracturing job. The first book devoted entirely to hydraulic fracturing chemicals, Fink eliminates the guesswork so the engineer can select the best chemicals needed on the job while providing the best protection for the well, workers and environment. Pinpoints the specific compounds used in any given fracturing operation Provides a systematic approach to class...

  15. 7 CFR 2902.10 - Mobile equipment hydraulic fluids.

    Science.gov (United States)

    2010-01-01

    ... Comprehensive Procurement Guideline, 40 CFR 247.11. ... 7 Agriculture 15 2010-01-01 2010-01-01 false Mobile equipment hydraulic fluids. 2902.10 Section... PROCUREMENT Designated Items § 2902.10 Mobile equipment hydraulic fluids. (a) Definition. Hydraulic...

  16. A New Type of Hydraulic Actuator Using Electrorheological Fluids

    Science.gov (United States)

    Wendt, Eckhard; Büsing, Klaus W.

    Electrorheological Fluids (ERF) are usually used in semi active damping elements, e.g. shock absorbers or engine mounts because of their continuously controllable shear stress. A totally new field of application may be achieved, if an ERF is used as a hydraulic fluid and not only as a control medium. In this case a fundamental need is the capability to produce a volume flow by using normal hydraulic pumps, e.g. gear pumps. The ERF and the hydraulic components both must have a long lifetime without unusual wear. Bayer AG has developed an ERF based on soft crosslinked PU-particles dispersed in silicone oil. These ERF are characterised by a low basic viscosity, a high ER-effect and a moderate conductivity. Compared with previous ERF where hard inorganic particles were used, the new fluid is not abrasive. It is foremostly this characteristic which gives the possibility of using the ERF in hydraulic systems with high shear rates and high shear stresses. The usage of ERF as hydraulic fluid allows the construction of proportional valves without mechanically driven parts. The control of the pressure drop over the valves is realised directly by an electrical signal. It is possible to realise actuators with very fast response times since the reaction time of ERF is within milliseconds. For demonstration purpose Bayer AG has built an actuator which is controlled by an electrorheological valve-block. The calculation of the dimension of this actuator and the valves will be shown and the realised response time will be demonstrated.

  17. High Pressure Hydraulic Distribution System

    Science.gov (United States)

    1991-05-20

    to 500 0 F. 5 cycles. 5000 F room temperature to 50001F; 45 ______________ Icycles The tesis planned for the distribution system demonstrator were...American Society for Testing and Materials ASTM D412 - Tension Testing of Vulcanized Rubber ASTM D571 - Testing Automotive Hydraulic Brake Hose Society of

  18. 46 CFR 58.30-10 - Hydraulic fluid.

    Science.gov (United States)

    2010-10-01

    ... manufacturers and ANSI B93.5 (incorporated by reference; see 46 CFR 58.03-1) shall be considered in the... 46 Shipping 2 2010-10-01 2010-10-01 false Hydraulic fluid. 58.30-10 Section 58.30-10 Shipping... AND RELATED SYSTEMS Fluid Power and Control Systems § 58.30-10 Hydraulic fluid. (a) The...

  19. Hydraulic forces caused by annular pressure seals in centrifugal pumps

    Science.gov (United States)

    Iino, T.; Kaneko, H.

    1980-01-01

    The hydraulic forces caused by annular pressure seals were investigated. The measured inlet and exit loss coefficients of the flow through the seals were much smaller than the conventional values. The results indicate that the damping coefficient and the inertia coefficient of the fluid film in the seal are not affected much by the rotational speed or the eccentricity of the rotor, though the stiffness coefficient seemed to be influenced by the eccentricity.

  20. Modeling of Propagation of Interacting Cracks Under Hydraulic Pressure Gradient

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hai [Idaho National Laboratory; Mattson, Earl Douglas [Idaho National Laboratory; Podgorney, Robert Karl [Idaho National Laboratory

    2015-04-01

    A robust and reliable numerical model for fracture initiation and propagation, which includes the interactions among propagating fractures and the coupling between deformation, fracturing and fluid flow in fracture apertures and in the permeable rock matrix, would be an important tool for developing a better understanding of fracturing behaviors of crystalline brittle rocks driven by thermal and (or) hydraulic pressure gradients. In this paper, we present a physics-based hydraulic fracturing simulator based on coupling a quasi-static discrete element model (DEM) for deformation and fracturing with conjugate lattice network flow model for fluid flow in both fractures and porous matrix. Fracturing is represented explicitly by removing broken bonds from the network to represent microcracks. Initiation of new microfractures and growth and coalescence of the microcracks leads to the formation of macroscopic fractures when external and/or internal loads are applied. The coupled DEM-network flow model reproduces realistic growth pattern of hydraulic fractures. In particular, simulation results of perforated horizontal wellbore clearly demonstrate that elastic interactions among multiple propagating fractures, fluid viscosity, strong coupling between fluid pressure fluctuations within fractures and fracturing, and lower length scale heterogeneities, collectively lead to complicated fracturing patterns.

  1. Fluid-solid interaction model for hydraulic reciprocating O-ring seals

    Science.gov (United States)

    Liao, Chuanjun; Huang, Weifeng; Wang, Yuming; Suo, Shuangfu; Liu, Ying

    2013-01-01

    Elastohydrodynamic lubrication characteristics of hydraulic reciprocating seals have significant effects on sealing and tribology performances of hydraulic actuators, especially in high parameter hydraulic systems. Only elastic deformations of hydraulic reciprocating seals were discussed, and hydrodynamic effects were neglected in many studies. The physical process of the fluid-solid interaction effect did not be clearly presented in the existing fluid-solid interaction models for hydraulic reciprocating O-ring seals, and few of these models had been simultaneously validated through experiments. By exploring the physical process of the fluid-solid interaction effect of the hydraulic reciprocating O-ring seal, a numerical fluid-solid interaction model consisting of fluid lubrication, contact mechanics, asperity contact and elastic deformation analyses is constructed with an iterative procedure. With the SRV friction and wear tester, the experiments are performed to investigate the elastohydrodynamic lubrication characteristics of the O-ring seal. The regularity of the friction coefficient varying with the speed of reciprocating motion is obtained in the mixed lubrication condition. The experimental result is used to validate the fluid-solid interaction model. Based on the model, The elastohydrodynamic lubrication characteristics of the hydraulic reciprocating O-ring seal are presented respectively in the dry friction, mixed lubrication and full film lubrication conditions, including of the contact pressure, film thickness, friction coefficient, liquid film pressure and viscous shear stress in the sealing zone. The proposed numerical fluid-solid interaction model can be effectively used to analyze the operation characteristics of the hydraulic reciprocating O-ring seal, and can also be widely used to study other hydraulic reciprocating seals.

  2. Disclosure of hydraulic fracturing fluid chemical additives: analysis of regulations.

    Science.gov (United States)

    Maule, Alexis L; Makey, Colleen M; Benson, Eugene B; Burrows, Isaac J; Scammell, Madeleine K

    2013-01-01

    Hydraulic fracturing is used to extract natural gas from shale formations. The process involves injecting into the ground fracturing fluids that contain thousands of gallons of chemical additives. Companies are not mandated by federal regulations to disclose the identities or quantities of chemicals used during hydraulic fracturing operations on private or public lands. States have begun to regulate hydraulic fracturing fluids by mandating chemical disclosure. These laws have shortcomings including nondisclosure of proprietary or "trade secret" mixtures, insufficient penalties for reporting inaccurate or incomplete information, and timelines that allow for after-the-fact reporting. These limitations leave lawmakers, regulators, public safety officers, and the public uninformed and ill-prepared to anticipate and respond to possible environmental and human health hazards associated with hydraulic fracturing fluids. We explore hydraulic fracturing exemptions from federal regulations, as well as current and future efforts to mandate chemical disclosure at the federal and state level.

  3. Safety estimation of high-pressure hydraulic cylinder using FSI method

    Institute of Scientific and Technical Information of China (English)

    KIM J.H.; HAN S.M.; KIM Y.J.

    2016-01-01

    Hydraulic cylinder is a primary component of the hydraulic valve systems.The numerical study of hydraulic cylinder to evaluate the stress analysis,the life assessment and the performance of operation characteristics in hydraulic cylinder were described.The calculation of safety factor,fatigue life,piston chamber pressure,rod chamber pressure and the change of velocity of piston with flow time after the beginning of hydraulic cylinder were incorporated.Numerical analysis was performed using the commercial CFD code,ANSYS with unsteady,dynamic mesh model,two-way FSI (fluid-struc-ture interaction)method and k-εturbulent model.The internal pressure in hydraulic cylinder through stress analysis show higher than those of the yield strength.

  4. SIMULATION OF FLUID FLOW IN CHANNEL OF A NOVEL HYDRAULIC SHOCK GENERATOR

    Institute of Scientific and Technical Information of China (English)

    Fu Xin; Yang Huayong

    2000-01-01

    In order to improve the engineering performance of a novel hydraulic shock generator,the fluid flow inside its complex passages is numerically investigated.The effects of the inlet flow velocity upon the turbulence intensity of the jet flow are analyzed.The calculated pressure loss is experimentally verified with the consideration of temperature determined viscosity shifting.The results are used as the reference in the further development of the hydraulic shock generator

  5. PRESSURE OSCILLATIONS IN TRANSIENT PROCESSES OF HYDRAULIC SYSTEMS WITH VARIABLE DISPLACEMENT PUMPS

    Directory of Open Access Journals (Sweden)

    Hennadii Zaionchkovskyi

    2015-12-01

    Full Text Available In aviation hydraulic drive of high power as a power supply the axial-piston variable displacement pumps became wide spreaded. The pump operational modes with air isolation and cavitation are accompanied by increased noise, delivery reduction and intensive pressure oscillations. The negative results of such phenomena are hydraulic elements erosion, pipeline fatigue failure, working fluid viscosity reduction and its contamination by wear products. The mechanism of cavitation rising in axial-piston pumps is considered, and factors which influence the cavitation rising and working fluid aeration are specified. The features of transient processes in aircraft hydraulic systems with variable displacement pumps are considered. It has been showed that as the pump delivery changes from its minimum to maximum great pressure oscillations in the aircraft pressure pipeline of the hydraulic system takes place, and have a negative influence on the pump service life. The recommendations concerning such pressure oscillation reduction are given.

  6. Quantifying the Efficiency Advantages of High Viscosity Index Hydraulic Fluids

    Institute of Scientific and Technical Information of China (English)

    Christian D. Neveu; Michael D. Zink; Alex Tsay

    2006-01-01

    By providing higher in- use viscosity at elevated operating temperatures, hydraulic fluids with high viscosity index improve the efficiency of the hydraulic system. For mobile hydraulic equipment this efficiency can be quantified as an increase in fuel economy. This paper reviews the research that demonstrates these efficiency advantages in gear, vane and piston pumps and presents a method for predicting the overall fuel economy for a fleet of hydraulic equipment in opquipment operator to easily improve the performance of the system and reduce fuel consumption.

  7. Design and Analysis of High Pressure Hydraulic Filter for Marine Application

    Science.gov (United States)

    Momin, Toshin; Chandrasekar, RP; Balasubramanian, S.; Junaid Basha, AM, Dr.

    2017-05-01

    Filter is a critical component in ahydraulic system for maintaining the cleanliness of the fluid to required class level. InMarine applications very high reliable filter is required to operate continuously in saline environment. Design anddevelopment of high pressure hydraulic filter for Marine application is a challenging task. The design involves selection of special materialsandstringent qualification tests as per International standards. The present paper describes various stages of design and development of high pressure hydraulic filter for Marine application.

  8. 流体属性可变的水压轴向柱塞泵压力流量模型%Pressure and flow characteristic modeling of water hydraulic axial piston pump based on variable fluid properties

    Institute of Scientific and Technical Information of China (English)

    翟江; 周华

    2013-01-01

    Considering cavitation due to the high saturation vapor pressure of water and main fluid properties variation-with pressure, a mathematical model of the dynamic pressure and flow characteristics of a water hydraulic axial piston pump was built. The model was programmed in a MATLAB/Simulink platform and a prototype of water hydraulic pump was simulated as an example. The pressure,flow and cavitation characteristics of the prototype were analyzed based on simulation results. The investigation shows that the average discharge flow of the pump will decrease, obvious cavitation will occur in the cylinder chambers that are in suction process,flow and pressure ripple will be severe when the inlet pressure is low. As the inlet pressure increases, the cavitation in the cylinder chambers will reduce and only occur in transition regions between discharge and suction. The internal leakage of the pump is mainly due to the gap flow of the slipper/swash plate combination and the cylinder block/valve plate combination, and the effects of the piston/cylinder-block can be ignored.%考虑了由于水的高饱和蒸汽压引起的空化及水的主要流体属性随压力变化的特性,建立了水压轴向柱塞泵的压力流量特性模型.以研制的水压轴向柱塞泵样机为例在MATLAB/Simulink环境下编程仿真,分析了泵的压力、流量和空化等特性.研究结果表明:泵入口压力较低时会引起排水流量的下降,在吸水区的缸体柱塞腔内出现明显的空化,泵出口的流量脉动和压力脉动大幅增加;提高泵的入口压力能够减小缸体柱塞腔内的空化程度,此时空化主要发生在由排水向吸水变换的瞬间;泵的内泄漏主要以滑靴副和配流副的泄露为主,柱塞副的泄露可以忽略.

  9. Pressure Characteristic Analysis of a Hydraulic System

    Science.gov (United States)

    Cho, H. Y.; Yang, H. J.

    2017-02-01

    EPPR(ElectroProportional Pressure Reducing) valve control the MCV(Main Control Valve) built on the mobile heavy machine. The EPPR valve was tested in the experimental setup and the performance of the valve was compared with that of the existing EPPR valve. On thisstudy, electromagnetic properties analysis using AMESim program was performed to optimize the designing of EPPR Valve (Electric Proportional Pressure Reducing Valve) and by applying its results to the hydraulic system analytical model, performance of the valve could be predicted. Also by comparing the results of the actual experiment and the simulation, The results of thisstudy is that the 3 factor(cone angle, tip width, clearance between sleeve and plunger) have much effectiveness than other components in the EPPR valve.

  10. Dynamic characteristics of Semi-active Hydraulic Engine Mount Based on Fluid-Structure Interaction FEA

    OpenAIRE

    Tian Jiande; Jiang Xue; Liu Guozheng; Shi Wenku; Liu Baoquan; Ma Meiqin

    2015-01-01

    A kind of semi-active hydraulic engine mount is studied in this paper. After careful analysis of its structure and working principle, the FEA simulation of it was divided into two cases. One is the solenoid valve is open, so the air chamber connects to the atmosphere, and Fluid-Structure Interaction was used. Another is the solenoid valve is closed, and the air chamber has pressure, so Fluid-Structure-Gas Interaction was used. The test of this semi-active hydraulic engine mount was carried ou...

  11. A nonlocal model for fluid-structure interaction with applications in hydraulic fracturing

    CERN Document Server

    Turner, Daniel Z

    2012-01-01

    Modeling important engineering problems related to flow-induced damage (in the context of hydraulic fracturing among others) depends critically on characterizing the interaction of porous media and interstitial fluid flow. This work presents a new formulation for incorporating the effects of pore pressure in a nonlocal representation of solid mechanics. The result is a framework for modeling fluid-structure interaction problems with the discontinuity capturing advantages of an integral based formulation. A number of numerical examples are used to show that the proposed formulation can be applied to measure the effect of leak-off during hydraulic fracturing as well as modeling consolidation of fluid saturated rock and surface subsidence caused by fluid extraction from a geologic reservoir. The formulation incorporates the effect of pore pressure in the constitutive description of the porous material in a way that is appropriate for nonlinear materials, easily implemented in existing codes, straightforward in i...

  12. Influences of Hydraulic Fracturing on Fluid Flow and Mineralization at the Vein-Type Tungsten Deposits in Southern China

    Directory of Open Access Journals (Sweden)

    Xiangchong Liu

    2017-01-01

    Full Text Available Wolframite is the main ore mineral at the vein-type tungsten deposits in the Nanling Range, which is a world-class tungsten province. It is disputed how wolframite is precipitated at these deposits and no one has yet studied the links of the mechanical processes to fluid flow and mineralization. Finite element-based numerical experiments are used to investigate the influences of a hydraulic fracturing process on fluid flow and solubility of CO2 and quartz. The fluids are aqueous NaCl solutions and fluid pressure is the only variable controlling solubility of CO2 and quartz in the numerical experiments. Significant fluctuations of fluid pressure and high-velocity hydrothermal pulse are found once rock is fractured by high-pressure fluids. The fluid pressure drop induced by hydraulic fracturing could cause a 9% decrease of quartz solubility. This amount of quartz deposition may not cause a significant decrease in rock permeability. The fluid pressure decrease after hydraulic fracturing also reduces solubility of CO2 by 36% and increases pH. Because an increase in pH would cause a major decrease in solubility of tungsten, the fluid pressure drop accompanying a hydraulic fracturing process facilitates wolframite precipitation. Our numerical experiments provide insight into the mechanisms precipitating wolframite at the tungsten deposits in the Nanling Range as well as other metals whose solubility is strongly dependent on pH.

  13. Application of computational fluid dynamics methods to improve thermal hydraulic code analysis

    Science.gov (United States)

    Sentell, Dennis Shannon, Jr.

    A computational fluid dynamics code is used to model the primary natural circulation loop of a proposed small modular reactor for comparison to experimental data and best-estimate thermal-hydraulic code results. Recent advances in computational fluid dynamics code modeling capabilities make them attractive alternatives to the current conservative approach of coupled best-estimate thermal hydraulic codes and uncertainty evaluations. The results from a computational fluid dynamics analysis are benchmarked against the experimental test results of a 1:3 length, 1:254 volume, full pressure and full temperature scale small modular reactor during steady-state power operations and during a depressurization transient. A comparative evaluation of the experimental data, the thermal hydraulic code results and the computational fluid dynamics code results provides an opportunity to validate the best-estimate thermal hydraulic code's treatment of a natural circulation loop and provide insights into expanded use of the computational fluid dynamics code in future designs and operations. Additionally, a sensitivity analysis is conducted to determine those physical phenomena most impactful on operations of the proposed reactor's natural circulation loop. The combination of the comparative evaluation and sensitivity analysis provides the resources for increased confidence in model developments for natural circulation loops and provides for reliability improvements of the thermal hydraulic code.

  14. Fluid Compressibility Effects during Hydraulic Fracture: an Opportunity for Gas Fracture Revival

    Science.gov (United States)

    Mighani, S.; Boulenouar, A.; Moradian, Z.; Evans, J. B.; Bernabe, Y.

    2015-12-01

    Hydraulic fracturing results when internal pore pressure is increased above a critical value. As the fracture extends, the fluid flows to the crack tip. The fracturing process depends strongly on the physical properties of both the porous solid and the fluid (e.g. porosity and elastic moduli for the solid, viscosity and compressibility for the fluid). It is also affected by the in-situ stress and pore pressure conditions. Here, we focus on the effect of fluid properties on hydraulic fracturing under conventional triaxial loading. Cylinders of Solnhofen limestone (a fine-grained, low permeability rock) were prepared with a central borehole through which different pressurized fluids such as oil, water or argon, were introduced. Preliminary experiments were performed using a confining pressure of 5 MPa and axial stress of 7 MPa. Our goal was to monitor fracture extension using strain gauges, acoustic emissions (AE) recording and ultrasonic velocity measurements. We also tried to compare the data with analytical models of fracture propagation. Initial tests showed that simple bi-wing fractures form when the fracturing fluid is relatively incompressible. With argon as pore fluid, a complex fracture network was formed. We also observed that the breakdown pressure was higher with argon than with less compressible fluids. After fracturing occurred, we cycled fluid pressure for several times. During the first cycles, re-opening of the fracture was associated with additional propagation. In general, it took 4 cycles to inhibit further propagation. Analytical models suggest that initial fractures occurring with compressible fluids tend to stabilize. Hence, formation and extension of additional fractures may occur, leading to a more complex morphology. Conversely, fractures formed by incompressible fluids remain critically stressed as they extend, thus producing a simple bi-wing fracture. Using compressible fracturing fluids could be a suitable candidate for an efficient

  15. Application study of magnetic fluid seal in hydraulic turbine

    Science.gov (United States)

    Yu, Z. Y.; Zhang, W.

    2012-11-01

    The waterpower resources of our country are abundant, and the hydroelectric power is developed, but at present the main shaft sealing device of hydraulic turbine is easy to wear and tear and the leakage is great. The magnetic fluid seal has the advantages of no contact, no wear, self-healing, long life and so on. In this paper, the magnetic fluid seal would be used in the main shaft of hydraulic turbine, the sealing structure was built the model, meshed the geometry, applied loads and solved by using MULTIPHYSICS in ANSYS software, the influence of the various sealing structural parameters such as tooth width, height, slot width, sealing gap on the sealing property were analyzed, the magnetic fluid sealing device suitable for large-diameter shaft and sealing water was designed, the sealing problem of the hydraulic turbine main shaft was solved effectively which will bring huge economic benefits.

  16. Flammability Tests on Hot Surface for Several Hydraulic Fluids

    Directory of Open Access Journals (Sweden)

    L. Deleanu

    2011-09-01

    Full Text Available Industrial equipment using hydraulic fluids are design to accept higher load and speed, implicitly higher temperatures, including for fluids. Leakages from enclosures like gear boxes or hydraulic systems could increase the risk of fluid reaching hot surfaces, thus producing fires hard to be controlled and isolated. The designer have to evaluate the flammability of fluids and they should select several solutions for a particular application in order to estimate the costs of different solutions and to mitigate the risk of having accidental fires due to a specific fluid grade. The tests were done with the help of an original equipment allowing a dedicated soft assistance in order to protect the operator and to sustain reproducibility, according to the standard SR EN ISO 20823:2004 Petroleum and related products. The determination of the flammability characteristics of fluids in contact with hot surfaces - Manifold ignition test, There were tested the following grades of hydraulic oil HLP 68 X-Oil, HFC Prista, MHE 40 Prista (100% oil, a rapeseed oil (obtained after a dewaxing process and an emulsion oil-in-water (5% vol. MHE 40 Prista. There were identified distinct behaviours of these fluids under the test conditions

  17. Effect of rock rheology on fluid leak- off during hydraulic fracturing

    Science.gov (United States)

    Yarushina, V. M.; Bercovici, D.; Oristaglio, M. L.

    2012-04-01

    In this communication, we evaluate the effect of rock rheology on fluid leak­off during hydraulic fracturing of reservoirs. Fluid leak-off in hydraulic fracturing is often nonlinear. The simple linear model developed by Carter (1957) for flow of fracturing fluid into a reservoir has three different regions in the fractured zone: a filter cake on the fracture face, formed by solid additives from the fracturing fluid; a filtrate zone affected by invasion of the fracturing fluid; and a reservoir zone with the original formation fluid. The width of each zone, as well as its permeability and pressure drop, is assumed to remain constant. Physical intuition suggests some straightforward corrections to this classical theory to take into account the pressure dependence of permeability, the compressibility or non-Newtonian rheology of fracturing fluid, and the radial (versus linear) geometry of fluid leak­off from the borehole. All of these refinements, however, still assume that the reservoir rock adjacent to the fracture face is non­deformable. Although the effect of poroelastic stress changes on leak-off is usually thought to be negligible, at the very high fluid pressures used in hydraulic fracturing, where the stresses exceed the rock strength, elastic rheology may not be the best choice. For example, calculations show that perfectly elastic rock formations do not undergo the degree of compaction typically seen in sedimentary basins. Therefore, pseudo-elastic or elastoplastic models are used to fit observed porosity profiles with depth. Starting from balance equations for mass and momentum for fluid and rock, we derive a hydraulic flow equation coupled with a porosity equation describing rock compaction. The result resembles a pressure diffusion equation with the total compressibility being a sum of fluid, rock and pore-space compressibilities. With linear elastic rheology, the bulk formation compressibility is dominated by fluid compressibility. But the possibility

  18. Theoretical aspects concerning working fluids in hydraulic systems

    Directory of Open Access Journals (Sweden)

    Tița Irina

    2017-01-01

    Full Text Available Among the properties of working fluid, viscosity is the most important as it regards especially to pumps. In order to study the behavior of hydrostatic transmission it is important to create a reliable research instrument for dynamic simulation. Our research expertise being in SimHydraulics consequently this instrument is the suitable block diagram. The purpose of this paper is to present the possible ways to customize the properties of the working fluid in the block diagram.

  19. Hydraulic fracturing fluid migration in the subsurface: A review and expanded modeling results

    Science.gov (United States)

    Birdsell, Daniel T.; Rajaram, Harihar; Dempsey, David; Viswanathan, Hari S.

    2015-09-01

    Understanding the transport of hydraulic fracturing (HF) fluid that is injected into the deep subsurface for shale gas extraction is important to ensure that shallow drinking water aquifers are not contaminated. Topographically driven flow, overpressured shale reservoirs, permeable pathways such as faults or leaky wellbores, the increased formation pressure due to HF fluid injection, and the density contrast of the HF fluid to the surrounding brine can encourage upward HF fluid migration. In contrast, the very low shale permeability and capillary imbibition of water into partially saturated shale may sequester much of the HF fluid, and well production will remove HF fluid from the subsurface. We review the literature on important aspects of HF fluid migration. Single-phase flow and transport simulations are performed to quantify how much HF fluid is removed via the wellbore with flowback and produced water, how much reaches overlying aquifers, and how much is permanently sequestered by capillary imbibition, which is treated as a sink term based on a semianalytical, one-dimensional solution for two-phase flow. These simulations include all of the important aspects of HF fluid migration identified in the literature review and are performed in five stages to faithfully represent the typical operation of a hydraulically fractured well. No fracturing fluid reaches the aquifer without a permeable pathway. In the presence of a permeable pathway, 10 times more fracturing fluid reaches the aquifer if well production and capillary imbibition are not included in the model.

  20. The study of crosslinked fluid leakoff in hydraulic fracturing physical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Grothe, Vinicius Perrud; Ribeiro, Paulo Roberto [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia de Petroleo; Sousa, Jose Luiz Antunes de Oliveira e [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia. Dept. de Estruturas; Fernandes, Paulo Dore [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2000-07-01

    The fluid loss plays an important role in the design and execution of hydraulic fracturing treatments. The main objectives of this work were: the study of the fluid loss associated with the propagation of hydraulic fractures generated at laboratory; and the comparison of two distinct methods for estimating leakoff coefficients - Nolte analysis and the filtrate volume vs. square root of time plot. Synthetic rock samples were used as well as crosslinked hydroxypropyl guar (HPG) fluids in different polymer concentrations. The physical simulations comprised the confinement of (0.1 x 0.1 x 0.1) m{sup 3} rock samples in a load cell for the application of an in situ stress field. Different flow rates were employed in order to investigate shear effects on the overall leakoff coefficient. Horizontal radial fractures were hydraulically induced with approximate diameters, what was accomplished by controlling the injection time. Leakoff coefficients determined by means of the pressure decline analysis were compared to coefficients obtained from static filtration tests, considering similar experimental conditions. The research results indicated that the physical simulation of hydraulic fracturing may be regarded as an useful tool for evaluating the effectiveness of fracturing fluids and that it can supply reliable estimates of fluid loss coefficients. (author)

  1. Dynamic characteristics of Semi-active Hydraulic Engine Mount Based on Fluid-Structure Interaction FEA

    Directory of Open Access Journals (Sweden)

    Tian Jiande

    2015-01-01

    Full Text Available A kind of semi-active hydraulic engine mount is studied in this paper. After careful analysis of its structure and working principle, the FEA simulation of it was divided into two cases. One is the solenoid valve is open, so the air chamber connects to the atmosphere, and Fluid-Structure Interaction was used. Another is the solenoid valve is closed, and the air chamber has pressure, so Fluid-Structure-Gas Interaction was used. The test of this semi-active hydraulic engine mount was carried out to compare with the simulation results, and verify the accuracy of the model. Then the dynamic characteristics-dynamic stiffness and damping angle were analysed by simulation and test. This paper provides theoretical support for the development and optimization of the semi-active hydraulic engine mount.

  2. PRESSURE COMPENSATION METHOD OF UNDERWATER HYDRAULIC SYSTEM WITH HYDRAULIC POWER UNIT BEING UNDER ATMOSPHERIC CIRCUMSTANCE AND PRESSURE COMPENSATED VALVE

    Institute of Scientific and Technical Information of China (English)

    Wang Qingfeng; Li Yanmin; Zhong Tianyu; Xu Guohua

    2005-01-01

    Based on the analysis of the-state-of-the-art of pressure compensation of underwater hydraulic systems (UHSs), a new method of pressure compensation of UHSs, whose hydraulic power unit is in the atmospheric circumstance, is proposed. And a pilot-operated relief valve with pressure compensation is realized. The pressure compensation precision is guaranteed by direct detection. Its dynamic performance and stability are improved by a dynamic feedback. Theoretical study, simulation and experiment show that the pilot-operated relief valve with pressure compensation has a fine property of tracking underwater ambient pressure and meet the requirement of underwater ambient pressure compensation.

  3. Process fluids of aero-hydraulic systems and their properties

    Directory of Open Access Journals (Sweden)

    I. S. Shumilov

    2014-01-01

    Full Text Available The article considers process fluids, which are presently applied to aviation hydraulic systems in domestic and world practice. Aviation practice deals with rather wide list of fluids. Based on the technical specification a designer makes the choice of specific fluid for the specific aircraft. Process fluids have to possess the specified properties presented in the article, namely: lubricating properties; stability of physical and chemical characteristics at operation and storage; lowtemperature properties; acceptable congelation temperature; compatibility with materials of units and components of hydraulic systems; heat conductivity; high rigidity; minimum low coefficient of volume expansion; fire-explosion safety; low density. They should also have good dielectric properties, be good to resist to destruction of molecules, have good anticorrosion and antierosion properties, as well as not create conditions for emerging electro-kinetic erosion of spooltype and other precision devices, and a number of other properties.The article presents materials on the oil-based process fluids with + (200-320 °C boiling temperature, gelled by a polymer of vinyl butyl ether, with aging inhibitor and dye for hydraulic systems of the subsonic and transonic aircraft which are combustible, with a temperature interval of use from — 60oС до +125oС. It also describes materials on process fluids, which are based on the mix of polydialkylsiloxane oligomers with organic diester aging inhibitors, and wear-resistant additive to be applied to the hydraulic systems of supersonic aircrafts using a fluid within the temperature interval from - 6О oС to +175oС for a long duration. The fire-explosion safety process fluids representing a mix of phosphoric esters with additives to improve viscous, anti-oxidizing, anticorrosive and anti-erosive properties are considered as well. They are used within the temperature range from - 60оС to +125оС with overheats up to +150

  4. Aerobic biodegradation of organic compounds in hydraulic fracturing fluids.

    Science.gov (United States)

    Kekacs, Daniel; Drollette, Brian D; Brooker, Michael; Plata, Desiree L; Mouser, Paula J

    2015-07-01

    Little is known of the attenuation of chemical mixtures created for hydraulic fracturing within the natural environment. A synthetic hydraulic fracturing fluid was developed from disclosed industry formulas and produced for laboratory experiments using commercial additives in use by Marcellus shale field crews. The experiments employed an internationally accepted standard method (OECD 301A) to evaluate aerobic biodegradation potential of the fluid mixture by monitoring the removal of dissolved organic carbon (DOC) from an aqueous solution by activated sludge and lake water microbial consortia for two substrate concentrations and four salinities. Microbial degradation removed from 57 % to more than 90 % of added DOC within 6.5 days, with higher removal efficiency at more dilute concentrations and little difference in overall removal extent between sludge and lake microbe treatments. The alcohols isopropanol and octanol were degraded to levels below detection limits while the solvent acetone accumulated in biological treatments through time. Salinity concentrations of 40 g/L or more completely inhibited degradation during the first 6.5 days of incubation with the synthetic hydraulic fracturing fluid even though communities were pre-acclimated to salt. Initially diverse microbial communities became dominated by 16S rRNA sequences affiliated with Pseudomonas and other Pseudomonadaceae after incubation with the synthetic fracturing fluid, taxa which may be involved in acetone production. These data expand our understanding of constraints on the biodegradation potential of organic compounds in hydraulic fracturing fluids under aerobic conditions in the event that they are accidentally released to surface waters and shallow soils.

  5. 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.

  6. Hydraulic study of drilling fluid flow in circular and annular tubes

    Energy Technology Data Exchange (ETDEWEB)

    Scheid, C.M.; Calcada, L.A.; Braga, E.R.; Paraiso, E.C.H. [Universidade Federal Rural do Rio de Janeiro (PPGEQ/UFRRJ), Seropedica, RJ (Brazil). Programa de Pos-Graduacao em Engenharia Quimica. Dept. de Engenharia Qumica], E-mail: calcada@ufrrj.br; Martins, A. L. [Petroleo Brasileiro S.A. (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2011-10-15

    This study investigates the drilling fluid flow behavior of two water-based drilling fluids in circular and annular tubes. The study has four main objectives: 1) to evaluate correlations between the Power Law and the Casson rheological models, 2) to characterize the flow behavior, 3) to evaluate five hydraulic-diameter equations, and 4) to evaluate the correlations of five turbulent flow-friction factors. The experimental fluid flow loop consisted of one positive displacement pump of 25 HP connected to a 500-liter tank agitated by a 3-HP mixer. The fluids passed through six meters long tubes, arranged in three horizontal rows with independent inlets and outlets. The circular tubes had a 1 inch diameter and were configured as two concentric annular tubes. Annular Tube I had an outer diameter of 1 1/4 inch and an inner diameter of 1/2 inch. Annular Tube II had an outer diameter of 2 inches and an inner diameter of 3/4 inch. The results show that, for the fluids in exam, correlations proposed in the literature were inaccurate as far as predicting hydraulic diameter, estimating pressure drop, and defining the flow regime. In general, the performance of those correlations depended on the fluid properties and on the system's geometry. Finally, literature parameters for some of the correlations were estimated for the two drilling fluids studied. These estimations improved the predictive capacity of calculating the friction factor for real drilling fluids applications for both circular and annular tubes. (author)

  7. Chemical Contamination Sensor for Phosphate Ester Hydraulic Fluids

    Directory of Open Access Journals (Sweden)

    Sumit Paul

    2010-01-01

    Full Text Available The paper deals with chemical contamination monitoring in phosphate-ester-based hydraulic fluids using nondispersive infrared (NDIR optical absorption. Our results show that NDIR monitoring allows detecting the take-up of water into such fluids and their hydrolytic disintegration as these become additionally stressed by Joule heating. Observations on the O–H stretching vibration band (3200–3800 cm−1 are used for determining the free water content (0–1.5% and the Total Acid Number (0–1 mgKOH/g. Both quantities can be assessed by monitoring the strength and the asymmetry of the O–H vibration band with regard to the free water absorption band centred around 3500 cm−1. As such optical parameters can be assessed without taking fluid samples from a pressurised hydraulic system, fluid degradation trends can be established based on regular measurements, before irreversible damage to the fluid has occurred. Therefore maintenance actions can be planned accordingly, which is very important for the airline, as unscheduled maintenance disturbs the flights organisation and often generates money loss.

  8. Sugarcane Tandem Mills Operation at Two Hydraulic Pressure Levels

    Directory of Open Access Journals (Sweden)

    Jorge Michel Corrales-Suárez

    2015-01-01

    Full Text Available Among the areas with more energy consumption in a sugar factory is the tandem of mills. The applied hydraulic pressure on the superior mace is one of the variables that have influence on this energy consumption. Hydraulic pressures were decreased in a value that did not affect the extraction process efficiency to determine the possibilities of decreasing this energy consumption. The research was carried out in two sugar cane tandems of six mills. The pressures were only varied in the extraction mills in humid according to a statistical design of experiments in random blocks. The results were analyzed by means of the analysis of variance of double classification. The independent variables were the hydraulic pressures in the intermediate mills while the dependent variables were the % pol and % humidity of the final bagasse. The hydraulic pressures of the intermediate mills were reduced 3.45 MPa in the Tandem 1 and 2.07 MPa in the Tandem 2. It was demonstrated that under the conditions of the experiment, the employment of working hydraulic pressures smaller than the usually established ones for each tandem did not affect the extraction process of the sugar cane sucrose significantly, but decreased 11.75% the power demand on tandem 1 and 8.17% on tandem 2.

  9. Stress dependent thermal pressurization of a fluid-saturated rock

    CERN Document Server

    Ghabezloo, Siavash

    2008-01-01

    Temperature increase in saturated porous materials under undrained conditions leads to thermal pressurization of the pore fluid due to the discrepancy between the thermal expansion coefficients of the pore fluid and of the solid matrix. This increase in the pore fluid pressure induces a reduction of the effective mean stress and can lead to shear failure or hydraulic fracturing. The equations governing the phenomenon of thermal pressurization are presented and this phenomenon is studied experimentally for a saturated granular rock in an undrained heating test under constant isotropic stress. Careful analysis of the effect of mechanical and thermal deformation of the drainage and pressure measurement system is performed and a correction of the measured pore pressure is introduced. The test results are modelled using a non-linear thermo-poro-elastic constitutive model of the granular rock with emphasis on the stress-dependent character of the rock compressibility. The effects of stress and temperature on therma...

  10. Influence of pore pressure to the development of a hydraulic fracture in poroelastic medium

    CERN Document Server

    Golovin, Sergey V

    2016-01-01

    In this paper we demonstrate the influence of the pore pressure to the development of a hydraulically-driven fracture in a poroelastic medium. We present a novel numerical model for propagation of a planar hydraulic fracture and prove its correctness by demonstration of the numerical convergence and by comparison with known solutions. The advantage of the algorithm is that it does not require the distinguishing of the fracture's tips and reconstruction of the numerical mesh according to the fracture propagation. Next, we perform a thorough analysis of the interplay of fluid filtration and redistribution of stresses near the fracture. We demonstrate that the fracture length decreases with the increase of the Biot's number (the parameter that determines the contribution of the pore pressure to the stress) and explain this effect by analysing the near-fracture pore pressure, rock deformation and stresses. We conclude, that the correct account for the fluid exchange between the fracture and the rock should be bas...

  11. Anaerobic Biodegradation of Ethylene Glycol within Hydraulic Fracturing Fluid

    Science.gov (United States)

    Heyob, K. M.; Mouser, P. J.

    2014-12-01

    Ethylene glycol (EG) is a commonly used organic additive in hydraulic fracturing fluids used for shale gas recovery. Under aerobic conditions, this compound readily biodegrades to acetate and CO2 or is oxidized through the glycerate pathway. In the absence of oxygen, organisms within genera Desulfovibrio, Acetobacterium, and others can transform EG to acetaldehyde, a flammable and suspected carcinogenic compound. Acetaldehyde can then be enzymatically degraded to ethanol or acetate and CO2. However, little is known on how EG degrades in the presence of other organic additives, particularly under anaerobic conditions representative of deep groundwater aquifers. To better understand the fate and attenuation of glycols within hydraulic fracturing fluids we are assessing their biodegradation potential and pathways in batch anaerobic microcosm treatments. Crushed Berea sandstone was inoculated with groundwater and incubated with either EG or a synthetic fracturing fluid (SFF) containing EG formulations. We tracked changes in dissolved organic carbon (DOC), EG, and its transformation products over several months. Approximately 41% of bulk DOC in SFF is degraded within 21 days, with 58% DOC still remaining after 63 days. By comparison, this same SFF degrades by 70% within 25 days when inoculated with sediment-groundwater microbial communities, suggesting that bulk DOC degradation occurs at a slower rate and to a lesser extent with bedrock. Aerobic biodegradation of EG occurs rapidly (3-7 days); however anaerobic degradation of EG is much slower, requiring several weeks for substantial DOC loss to be observed. Ongoing experiments are tracking the degradation pathways of EG alone and in the presence of SFF, with preliminary data showing incomplete glycol transformation within the complex hydraulic fracturing fluid mixture. This research will help to elucidate rates, processes, and pathways for EG biodegradation and identify key microbial taxa involved in its degradation.

  12. Numerical Investigation of Influence of In-Situ Stress Ratio, Injection Rate and Fluid Viscosity on Hydraulic Fracture Propagation Using a Distinct Element Approach

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2016-02-01

    Full Text Available Numerical simulation is very useful for understanding the hydraulic fracturing mechanism. In this paper, we simulate the hydraulic fracturing using the distinct element approach, to investigate the effect of some critical parameters on hydraulic fracturing characteristics. The breakdown pressure obtained by the distinct element approach is consistent with the analytical solution. This indicates that the distinct element approach is feasible on modeling the hydraulic fracturing. We independently examine the influence of in-situ stress ratio, injection rate and fluid viscosity on hydraulic fracturing. We further emphasize the relationship between these three factors and their contributions to the hydraulic fracturing. With the increase of stress ratio, the fracture aperture increases almost linearly; with the increase of injection rate and fluid viscosity, the fracture aperture and breakdown pressure increase obviously. A low value of product of injection rate and fluid viscosity (i.e., Qμ will lead to narrow fracture aperture, low breakdown pressure, and complex or dispersional hydraulic fractures. A high value of Qμ would lead wide fracture aperture, high breakdown pressure, and simple hydraulic fractures (e.g., straight or wing shape. With low viscosity fluid, the hydraulic fracture geometry is not sensitive to stress ratio, and thus becomes a complex fracture network.

  13. Bench-mark solution for a penny-shaped hydraulic fracture driven by a thinning fluid

    CERN Document Server

    Linkov, Aleksandr

    2015-01-01

    The paper presents a solution for axisymmetric propagation of a penny-shaped crack driven by a thinning fluid. The solution to the accuracy of four significant digits, at least, is obtained on the basis of the modified formulation of hydraulic fracture problem by employing the particle velocity, rather than conventionally used flux. This serves to properly organize iterations in the opening after reducing the problem to the self-similar form. Numerical results obtained show relatively small dependence of self-similar quantities (fracture radius, propagation speed, opening, particle velocity, pressure, flux) on the behavior index of a thinning fluid. The results provide bench marks for the accuracy control of truly 3D simulators and they serve for assigning an apparent viscosity when simulating the action of a thinning fluid by replacing it with an equivalent Newtonian fluid.

  14. Servo Controlled Variable Pressure Modification to Space Shuttle Hydraulic Pump

    Science.gov (United States)

    Kouns, H. H.

    1983-01-01

    Engineering drawings show modifications made to the constant pressure control of the model AP27V-7 hydraulic pump to an electrically controlled variable pressure setting compensator. A hanger position indicator was included for continuously monitoring hanger angle. A simplex servo driver was furnished for controlling the pressure setting servovalve. Calibration of the rotary variable displacement transducer is described as well as pump performance and response characteristics.

  15. Stimuli Responsive/Rheoreversible Hydraulic Fracturing Fluids for Enhanced Geothermal Energy Production (Part II)

    Energy Technology Data Exchange (ETDEWEB)

    Bonneville, Alain; Jung, Hun Bok; Shao, Hongbo; Kabilan, Senthil; Um, Wooyong; Carroll, Kenneth C.; Varga, Tamas; Suresh, Niraj; Stephens, Sean A.; Fernandez, Carlos A.

    2014-12-14

    We have used an environmentally friendly and recyclable hydraulic fracturing fluid - diluted aqueous solutions of polyallylamine or PAA – for reservoir stimulation in Enhanced Geothermal System (EGS). This fluid undergoes a controlled and large volume expansion with a simultaneous increase in viscosity triggered by CO2 at EGS temperatures. We are presenting here the results of laboratory-scale hydraulic fracturing experiment using the fluid on small cylindrical rock cores (1.59 cm in diameter and 5.08 cm in length) from the Coso geothermal field in California. Rock samples consisted of Mesozoic diorite metamorphosed to greenschist facies. The experiments were conducted on 5 samples for realistic ranges of pressures (up to 275 bar) and temperatures (up to 210 °C) for both the rock samples and the injected fluid. After fracturing, cores were subjected to a CO2 leakage test, injection of KI solution, and X-ray microtomography (XMT) scanning to examine the formation and distribution of fractures. The design and conduct of these experiments will be presented and discussed in details. Based on the obtained XMT images, Computational Fluid Dynamics (CFD) simulations were then performed to visualize hydraulic fractures and compute the bulk permeability. OpenFOAM (OpenCFD Ltd., Reading, UK), was used to solve the steady state simulation. The flow predictions, based upon the laminar, 3-D, incompressible Navier-Stokes equations for fluid mass and momentum, show the remarkable stimulation of the permeability in the core samples and demonstrate the efficiency of such a CO2 triggered fluid in EGS.

  16. Organic compounds in hydraulic fracturing fluids and wastewaters: A review.

    Science.gov (United States)

    Luek, Jenna L; Gonsior, Michael

    2017-10-15

    High volume hydraulic fracturing (HVHF) of shale to stimulate the release of natural gas produces a large quantity of wastewater in the form of flowback fluids and produced water. These wastewaters are highly variable in their composition and contain a mixture of fracturing fluid additives, geogenic inorganic and organic substances, and transformation products. The qualitative and quantitative analyses of organic compounds identified in HVHF fluids, flowback fluids, and produced waters are reviewed here to communicate knowledge gaps that exist in the composition of HVHF wastewaters. In general, analyses of organic compounds have focused on those amenable to gas chromatography, focusing on volatile and semi-volatile oil and gas compounds. Studies of more polar and non-volatile organic compounds have been limited by a lack of knowledge of what compounds may be present as well as quantitative methods and standards available for analyzing these complex mixtures. Liquid chromatography paired with high-resolution mass spectrometry has been used to investigate a number of additives and will be a key tool to further research on transformation products that are increasingly solubilized through physical, chemical, and biological processes in situ and during environmental contamination events. Diverse treatments have been tested and applied to HVHF wastewaters but limited information has been published on the quantitative removal of individual organic compounds. This review focuses on recently published information on organic compounds identified in flowback fluids and produced waters from HVHF. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. 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.

  18. Field Demonstration of Military Bio-based Hydraulic Fluids Using Construction Equipment at Fort Leonard Wood

    Science.gov (United States)

    2009-05-01

    Committed to Excellence 4-7 May 2009 1 Field Demonstration of Military Bio -based Hydraulic Fluids Using Construction Equipment at Fort Leonard Wood...AND SUBTITLE Field Demonstration of Military Bio -based Hydraulic Fluids Using Construction Equipment at Fort Leonard Wood 5a. CONTRACT NUMBER 5b...4-7 May 2009 2 Outline  Background  Military Bio -based Hydraulic Fluid Specification  Field Demonstration and Results  Conclusions 4-7 May

  19. Analysis and control of flows in pressurized hydraulic networks

    NARCIS (Netherlands)

    Gupta, R.K.

    2006-01-01

    Analysis, design and flow control problems in pressurized hydraulic networks such as water transmission and distribution systems consisting of pipes and other appurtenant components such as reservoirs, pumps, valves and surge devices are dealt with from the prospective of network synthesis aiming at

  20. Quantized pressure control in large-scale nonlinear hydraulic networks

    NARCIS (Netherlands)

    Persis, Claudio De; Kallesøe, Carsten Skovmose; Jensen, Tom Nørgaard

    2010-01-01

    It was shown previously that semi-global practical pressure regulation at designated points of a large-scale nonlinear hydraulic network is guaranteed by distributed proportional controllers. For a correct implementation of the control laws, each controller, which is located at these designated poin

  1. Analysis and control of flows in pressurized hydraulic networks

    NARCIS (Netherlands)

    Gupta, R.K.

    2006-01-01

    Analysis, design and flow control problems in pressurized hydraulic networks such as water transmission and distribution systems consisting of pipes and other appurtenant components such as reservoirs, pumps, valves and surge devices are dealt with from the prospective of network synthesis aiming at

  2. Experimental Validation of Modelled Fluid Forces in Fast Switching Hydraulic On/Off Valves

    DEFF Research Database (Denmark)

    Nørgård, Christian; Bech, Michael Møller; Roemer, Daniel Beck;

    2015-01-01

    A prototype of a fast switching valve for a digital hydraulic machine has been designed and manufactured. The valve is composed of an annular seat plunger connected with a moving coil actuator as the force producing element. The valve prototype is designed for flow rates of 600 l/min with less than...... 0.5 bar pressure drop, and the models predicts a switching time in the region of a millisecond with a travel length of 3.5 mm using an average power of 250 W. The total machine efficiency when neglecting losses not related to the valves is above 98 %. The objective of this paper is to experimentally...... validate a transient computational fluid dynamics (CFD) model of the fluid forces that oppose the valve plunger when moving rapidly through the surrounding oil during switching. Due to the fast switching of the valve, the fluid forces which oppose plunger movement increases drastically as the plunger...

  3. Determination of hydraulic fracture parameters using a non-stationary fluid injection

    Science.gov (United States)

    Valov, A. V.; Golovin, S. V.

    2016-06-01

    In this paper, one provides a theoretical justification of the possibility of hydraulic fracture parameters determination by using a non-stationary fluid injection. It is assumed that the fluid is pumped into the fractured well with the time-periodic flow rate. It is shown that there is a phase shift between waves of fluid pressure and velocity. For the modelling purposes, the length and width of the fracture are assumed to be fixed. In the case of infinite fracture, one constructs an exact solution that ensures analytical determination of the phase shift in terms of the physical parameters of the problem. In the numerical calculation, the phase shift between pressure and velocity waves is found for a finite fracture. It is shown that the value of the phase shift depends on the physical parameters and on the fracture geometry. This makes it possible to determine parameters of hydraulic fracture, in particular its length, by the experimental measurement of the time shift and comparison with the numerical solution.

  4. The coupled effect of fiber volume fraction and void fraction on hydraulic fluid absorption of quartz/BMI laminates

    Science.gov (United States)

    Hurdelbrink, Keith R.; Anderson, Jacob P.; Siddique, Zahed; Altan, M. Cengiz

    2016-03-01

    Bismaleimide (BMI) resin with quartz (AQ581) fiber reinforcement is a composite material frequently used in aerospace applications, such as engine cowlings and radomes. Various composite components used in aircrafts are exposed to different types of hydraulic fluids, which may lead to anomalous absorption behavior over the service life of the composite. Accurate predictive models for absorption of liquid penetrants are particularly important as the composite components are often exposed to long-term degradation due to absorbed moisture, hydraulic fluids, or similar liquid penetrants. Microstructural features such as fiber volume fraction and void fraction can have a significant effect on the absorption behavior of fiber-reinforced composites. In this paper, hydraulic fluid absorption characteristics of quartz/BMI laminates fabricated from prepregs preconditioned at different relative humidity and subsequently cured at different pressures are presented. The composite samples are immersed into hydraulic fluid at room temperature, and were not subjected to any prior degradation. To generate process-induced microvoids, prepregs were conditioned in an environmental chamber at 2% or 99% relative humidity at room temperature for a period of 24 hours prior to laminate fabrication. To alter the fiber volume fraction, the laminates were fabricated at cure pressures of 68.9 kPa (10 psi) or 482.6 kPa (70 psi) via a hot-press. The laminates are shown to have different levels of microvoids and fiber volume fractions, which were observed to affect the absorption dynamics considerably and exhibited clear non-Fickian behavior. A one-dimensional hindered diffusion model (HDM) was shown to be successful in predicting the hydraulic fluid absorption. Model prediction indicates that as the fabrication pressure increased from 68.9 kPa to 482.6 kPa, the maximum fluid content (M∞) decreased from 8.0% wt. to 1.0% wt. The degree of non-Fickian behavior, measured by hindrance coefficient (

  5. Controlling a negative loaded hydraulic cylinder using pressure feedback

    DEFF Research Database (Denmark)

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

    2010-01-01

    the high pass filtered pressure gradient equal tozero is introduced. It yields lead compensation with a markedly improved performance. The sizing of the filter is described taking into account the bandwidth of the directional control valve. The suggested control scheme is implemented and examined......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...... showing that without extra measures such a system will be unstable in a substantial part of the cylinder stroke. The stability criterion is expressed in hard quantities: Cylinder volumes, cylinder area ratio and overcenter valve pilot area ratio. A pressure feed back scheme that has as target to maintain...

  6. Overview of Chronic Oral Toxicity Values for Chemicals Present in Hydraulic Fracturing Fluids, Flowback and Produced Waters

    Science.gov (United States)

    as part of EPA's Hydraulic Fracturing Drinking Water Assessment, EPA is summarizing existing toxicity data for chemicals reported to be used in hydraulic fracturing fluids and/or found in flowback or produced waters from hydraulically fractured wells

  7. Biocides in hydraulic fracturing fluids: a critical review of their usage, mobility, degradation, and toxicity.

    Science.gov (United States)

    Kahrilas, Genevieve A; Blotevogel, Jens; Stewart, Philip S; Borch, Thomas

    2015-01-06

    Biocides are critical components of hydraulic fracturing ("fracking") fluids used for unconventional shale gas development. Bacteria may cause bioclogging and inhibit gas extraction, produce toxic hydrogen sulfide, and induce corrosion leading to downhole equipment failure. The use of biocides such as glutaraldehyde and quaternary ammonium compounds has spurred a public concern and debate among regulators regarding the impact of inadvertent releases into the environment on ecosystem and human health. This work provides a critical review of the potential fate and toxicity of biocides used in hydraulic fracturing operations. We identified the following physicochemical and toxicological aspects as well as knowledge gaps that should be considered when selecting biocides: (1) uncharged species will dominate in the aqueous phase and be subject to degradation and transport whereas charged species will sorb to soils and be less bioavailable; (2) many biocides are short-lived or degradable through abiotic and biotic processes, but some may transform into more toxic or persistent compounds; (3) understanding of biocides' fate under downhole conditions (high pressure, temperature, and salt and organic matter concentrations) is limited; (4) several biocidal alternatives exist, but high cost, high energy demands, and/or formation of disinfection byproducts limits their use. This review may serve as a guide for environmental risk assessment and identification of microbial control strategies to help develop a sustainable path for managing hydraulic fracturing fluids.

  8. Schaum’s outline of fluid mechanics and hydraulics

    CERN Document Server

    Giles, Ranald V; Liu, Cheng

    2014-01-01

    Tough Test Questions? Missed Lectures? Not Enough Time? Fortunately, there's Schaum's. More than 40 million students have trusted Schaum's to help them succeed in the classroom and on exams. Schaum's is the key to faster learning and higher grades in every subject. Each Outline presents all the essential course information in an easy-to-follow, topic-by-topic format. You also get hundreds of examples, solved problems, and practice exercises to test your skills. This Schaum's Outline gives you: 622 fully solved problems; extra practice on topics such as buoyancy and flotation, complex pipeline systems, fluid machinery, flow in open channels, and more; and support for all the major textbooks for fluidmechanics and hydraulics courses. Fully compatible with your classroom text, Schaum's highlights all the important facts you need to know. Use Schaum's to shorten your study time - and get your best test scores! Schaum's Outlines - Problem Solved.

  9. Characteristics of a hydraulic jump in Bingham fluid

    CERN Document Server

    Shu, Jian-Jun

    2014-01-01

    In this paper, we seek an adequate macroscopic model for a hydraulic jump in Bingham fluid. The formulas for conjugate depths, sequent bottom shear stress and critical depth are established. Since no exact analytical solution in closed form is available for conjugate depths, an approximate formula is developed. This formula can provide good results with an error less than 4%. The analytical results have revealed that the critical depth and the ratio of conjugate depths increase until bottom shear stress exceeds a certain value and then decrease afterwards. The bottom shear stress downstream of the jump is smaller than that upstream. The results are verified by experimental data and observations available in the literature.

  10. Contamination Control and Monitoring of Tap Water as Fluid in Industrial Tap Water Hydraulic Systems

    DEFF Research Database (Denmark)

    Conrad, Finn; Adelstorp, Anders

    1998-01-01

    Presentation of results and methods addressed to contamination control and monitoring of tap water as fluid in tap water hydraulic systems.......Presentation of results and methods addressed to contamination control and monitoring of tap water as fluid in tap water hydraulic systems....

  11. Contamination Control and Monitoring of Tap Water as Fluid in Industrial Tap Water Hydraulic Systems

    DEFF Research Database (Denmark)

    Conrad, Finn; Adelstorp, Anders

    1998-01-01

    Presentation of results and methods addressed to contamination control and monitoring of tap water as fluid in tap water hydraulic systems.......Presentation of results and methods addressed to contamination control and monitoring of tap water as fluid in tap water hydraulic systems....

  12. Effects of shifting time on pressure impact in hydraulic systems

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhen-cai; CHEN Guo-an

    2005-01-01

    The limitations in existing measures for absorbing pressure impact in hydraulic systems were summarized in this paper. Based on the forming principle of the oil in a hydrostatic closed pressure chamber, the underlying reasons of the pressure impact were analyzed theoretically, the intrinsic laws that the extent of the pressure impact in hydraulic oil lines are affected by some factors, such as oil elastic modulus, oil line's geometrical volume, and changing rate of oil volume versus time etc, were discussed. Experimental investigations into pressure impact in all pressure chambers because of shifting were conducted under different working conditions by employing a special experimental system. The effects of shifting time on pressure impact were studied. A new concept with universal meaning, i.e. optimal shifting time, and its characterizing parameter and the methods of shifting at optimal shifting time were also proposed. The results show that shifting time lag △t is of rationality and maneuverablility. The higher the working pressure, the shorter the shifting time.

  13. Fiber bundle model under fluid pressure

    Science.gov (United States)

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting.

  14. Fluid-dynamic design optimization of hydraulic proportional directional valves

    Science.gov (United States)

    Amirante, Riccardo; Catalano, Luciano Andrea; Poloni, Carlo; Tamburrano, Paolo

    2014-10-01

    This article proposes an effective methodology for the fluid-dynamic design optimization of the sliding spool of a hydraulic proportional directional valve: the goal is the minimization of the flow force at a prescribed flow rate, so as to reduce the required opening force while keeping the operation features unchanged. A full three-dimensional model of the flow field within the valve is employed to accurately predict the flow force acting on the spool. A theoretical analysis, based on both the axial momentum equation and flow simulations, is conducted to define the design parameters, which need to be properly selected in order to reduce the flow force without significantly affecting the flow rate. A genetic algorithm, coupled with a computational fluid dynamics flow solver, is employed to minimize the flow force acting on the valve spool at the maximum opening. A comparison with a typical single-objective optimization algorithm is performed to evaluate performance and effectiveness of the employed genetic algorithm. The optimized spool develops a maximum flow force which is smaller than that produced by the commercially available valve, mainly due to some major modifications occurring in the discharge section. Reducing the flow force and thus the electromagnetic force exerted by the solenoid actuators allows the operational range of direct (single-stage) driven valves to be enlarged.

  15. Design of a Magnetostrictive-Hydraulic Actuator Considering Nonlinear System Dynamics and Fluid-Structure Coupling

    Science.gov (United States)

    Larson, John Philip

    Smart material electro-hydraulic actuators (EHAs) utilize fluid rectification via one-way check valves to amplify the small, high-frequency vibrations of certain smart materials into large motions of a hydraulic cylinder. Although the concept has been demonstrated in previously, the operating frequency of smart material EHA systems has been limited to a small fraction of the available bandwidth of the driver materials. The focus of this work is to characterize and model the mechanical performance of a magnetostrictive EHA considering key system components: rectification valves, smart material driver, and fluid-system components, leading to an improved actuator design relative to prior work. The one-way valves were modeled using 3-D finite element analysis, and their behavior was characterized experimentally by static and dynamic experimental measurement. Taking into account the effect of the fluid and mechanical conditions applied to the valves within the pump, the dynamic response of the valve was quantified and applied to determine rectification bandwidth of different valve configurations. A novel miniature reed valve, designed for a frequency response above 10~kHz, was fabricated and tested within a magnetostrictive EHA. The nonlinear response of the magnetostrictive driver, including saturation and hysteresis effects, was modeled using the Jiles-Atherton approach to calculate the magnetization and the resulting magnetostriction based on the applied field calculated within the rod from Maxwell's equations. The dynamic pressure response of the fluid system components (pumping chamber, hydraulic cylinder, and connecting passages) was measured over a range of input frequencies. For the magnetostrictive EHA tested, the peak performance frequency was found to be limited by the fluid resonances within the system. A lumped-parameter modeling approach was applied to model the overall behavior of a magnetostrictive EHA, incorporating models for the reed valve response

  16. 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.

  17. 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.

  18. 30 CFR 35.4 - Types of hydraulic fluid for which certificates of approval may be granted.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Types of hydraulic fluid for which certificates..., DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS FIRE-RESISTANT HYDRAULIC FLUIDS General Provisions § 35.4 Types of hydraulic fluid for which certificates of approval may be...

  19. 30 CFR 75.1107-1 - Fire-resistant hydraulic fluids and fire suppression devices on underground equipment.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fire-resistant hydraulic fluids and fire...-UNDERGROUND COAL MINES Fire Protection Fire Suppression Devices and Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1107-1 Fire-resistant hydraulic fluids and fire suppression devices on...

  20. Characterization of the Oriskany and Berea Sandstones: Evaluating Biogeochemical Reactions of Potential Sandstone–Hydraulic Fracturing Fluid Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Verba, Circe [National Energy Technology Lab. (NETL), Albany, OR (United States); Harris, Aubrey [National Energy Technology Lab. (NETL), Albany, OR (United States)

    2016-07-07

    The Marcellus shale, located in the mid-Atlantic Appalachian Basin, has been identified as a source for natural gas and targeted for hydraulic fracturing recovery methods. Hydraulic fracturing is a technique used by the oil and gas industry to access petroleum reserves in geologic formations that cannot be accessed with conventional drilling techniques (Capo et al., 2014). This unconventional technique fractures rock formations that have low permeability by pumping pressurized hydraulic fracturing fluids into the subsurface. Although the major components of hydraulic fracturing fluid are water and sand, chemicals, such as recalcitrant biocides and polyacrylamide, are also used (Frac Focus, 2015). There is domestic concern that the chemicals could reach groundwater or surface water during transport, storage, or the fracturing process (Chapman et al., 2012). In the event of a surface spill, understanding the natural attenuation of the chemicals in hydraulic fracturing fluid, as well as the physical and chemical properties of the aquifers surrounding the spill site, will help mitigate potential dangers to drinking water. However, reports on the degradation pathways of these chemicals are limited in existing literature. The Appalachian Basin Marcellus shale and its surrounding sandstones host diverse mineralogical suites. During the hydraulic fracturing process, the hydraulic fracturing fluids come into contact with variable mineral compositions. The reactions between the fracturing fluid chemicals and the minerals are very diverse. This report: 1) describes common minerals (e.g. quartz, clay, pyrite, and carbonates) present in the Marcellus shale, as well as the Oriskany and Berea sandstones, which are located stratigraphically below and above the Marcellus shale; 2) summarizes the existing literature of the degradation pathways for common hydraulic fracturing fluid chemicals [polyacrylamide, ethylene glycol, poly(diallyldimethylammonium chloride), glutaraldehyde

  1. Validation of NIS 500 MPa hydraulic pressure measurement

    Directory of Open Access Journals (Sweden)

    Eltawil Alaaeldin A.

    2017-01-01

    Full Text Available 500 MPa pressure is considered as the common maximum pressure in most of the National Metrology Institutes worldwide; however, validation of the uncertainty in that range required a lot of work. NIS when recognized on, 2008 guaranteed big uncertainty value above 200 MPa due to the absence of international comparison at that time. This paper summarizes the results of a validation of 500 MPa range of hydraulic gauge pressure measurements carried out at NIS. The study covers the calibration through direct comparison and through using of a pressure sensor. The paper summarized the technical work carried out at the results of measurements and the effect of these results on NIS Calibration Measurements Capability. The validation also includes the comparison between the obtained results and pervious calibration of the same piston-cylinder assembly that calibrated against the NIST primary standard.

  2. 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.

  3. Environmentally Friendly, Rheoreversible, Hydraulic-fracturing Fluids for Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Hongbo; Kabilan, Senthil; Stephens, Sean A.; Suresh, Niraj; Beck, Anthon NR; Varga, Tamas; Martin, Paul F.; Kuprat, Andrew P.; Jung, Hun Bok; Um, Wooyong; Bonneville, Alain; Heldebrant, David J.; Carroll, KC; Moore, Joseph; Fernandez, Carlos A.

    2015-07-01

    Cost-effective creation of high-permeability reservoirs inside deep crystalline bedrock is the primary challenge for the feasibility of enhanced geothermal systems (EGS). Current reservoir stimulation entails adverse environmental impacts and substantial economic costs due to the utilization of large volumes of water “doped” with chemicals including rheology modifiers, scale and corrosion inhibitors, biocides, friction reducers among others where, typically, little or no information of composition and toxicity is disclosed. An environmentally benign, CO2-activated, rheoreversible fracturing fluid has recently been developed that significantly enhances rock permeability at effective stress significantly lower than current technology. We evaluate the potential of this novel fracturing fluid for application on geothermal sites under different chemical and geomechanical conditions, by performing laboratory-scale fracturing experiments with different rock sources under different confining pressures, temperatures, and pH environments. The results demonstrate that CO2-reactive aqueous solutions of environmentally amenable Polyallylamine (PAA) represent a highly versatile fracturing fluid technology. This fracturing fluid creates/propagates fracture networks through highly impermeable crystalline rock at significantly lower effective stress as compared to control experiments where no PAA was present, and permeability enhancement was significantly increased for PAA compared to conventional hydraulic fracturing controls. This was evident in all experiments, including variable rock source/type, operation pressure and temperature (over the entire range for EGS applications), as well as over a wide range of formation-water pH values. This versatile novel fracturing fluid technology represents a great alternative to industrially available fracturing fluids for cost-effective and competitive geothermal energy production.

  4. Effects of hydraulic frac fluids and formation waters on groundwater microbial communities

    Science.gov (United States)

    Krueger, Martin; Jimenez, Nuria

    2017-04-01

    Shale gas is being considered as a complementary energy resource to other fossil fuels. Its exploitation requires using advanced drilling techniques and hydraulic stimulation (fracking). During fracking operations, large amounts of fluids (fresh water, proppants and chemicals) are injected at high pressures into the formations, to create fractures and fissures, and thus to release gas from the source rock into the wellbore. The injected fluid partly remains in the formation, while up to 40% flows back to the surface, together with reservoir waters, sometimes containing dissolved hydrocarbons, high salt concentrations, etc. The aim of our study was to investigate the potential impacts of frac or geogenic chemicals, frac fluid, formation water or flowback on groudnwater microbial communities. Laboratory experiments under in situ conditions (i.e. at in situ temperature, high pressure) were conducted using groundwater samples from three different locations. Series of microcosms containing R2 broth medium or groundwater spiked with either single frac chemicals (including biocides), frac fluids, artificial reservoir water, NaCl, or different mixtures of reservoir water and frac fluid (to simulate flowback) were incubated in the dark. Controls included non-amended and non-inoculated microcosms. Classical microbiological methods and molecular analyses were used to assess changes in the microbial abundance, community structure and function in response to the different treatments. Microbial communities were quite halotolerant and their growth benefited from low concentrations of reservoir waters or salt, but they were negatively affected by higher concentrations of formation waters, salt, biocides or frac fluids. Changes on the microbial community structure could be detected by T-RFLP. Single frac components like guar gum or choline chloride were used as substrates, while others like triethanolamine or light oil distillate hydrogenated prevented microbial growth in

  5. Effects of hydraulic frac fluids and formation waters on groundwater microbial communities

    Science.gov (United States)

    Jiménez, Núria; Krüger, Martin

    2015-04-01

    Shale gas is being considered as a complementary energy resource to other fossil fuels. Its exploitation requires using advanced drilling techniques and hydraulic stimulation (fracking). During fracking operations, large amounts of fluids (fresh water, proppants and chemicals) are injected at high pressures into the formations, to create fractures and fissures, and thus to release gas from the source rock into the wellbore. The injected fluid partly remains in the formation, while up to 40% flows back to the surface, together with reservoir waters, sometimes containing dissolved hydrocarbons, high salt concentrations, etc. The aim of our study was to investigate the potential impacts of frac or geogenic chemicals, frac fluid, formation water or flowback on groudnwater microbial communities. Laboratory experiments under in situ conditions (i.e. at in situ temperatures, with high pressure, etc.) were conducted using groundwater samples from three different locations. Series of microcosms (3 of each kind) containing R2 broth medium or groundwater spiked with either single frac chemicals (including biocides), frac fluids, artificial reservoir water, NaCl, or different mixtures of reservoir water and frac fluid (to simulate flowback) were incubated in the dark. Controls included non-amended and non-inoculated microcosms. Classical microbiological methods and molecular analyses were used to assess changes in the microbial abundance, community structure and function in response to the different treatments. Microbial communities were quite halotolerant and their growth benefited from low concentrations of reservoir waters or salt, but they were negatively affected by higher concentrations of formation waters, salt, biocides, frac fluids or flowback. Changes on the microbial community structure could be detected by T-RFLP. Single frac components like guar gum or choline chloride could be used as substrates, while the effects of others like triethanolamine or light oil

  6. Blade-shaped (PKN) Hydraulic Fracture Driven By A Turbulent Fluid In An Impermeable Rock

    CERN Document Server

    Zolfaghari, Navid; Bunger, Andrew P

    2016-01-01

    High flow rate, water-driven hydraulic fractures are more common now than ever in the oil and gas industry. Although the fractures are small, the high injection rate and low viscosity of the water, lead to high Reynolds numbers and potentially turbulence in the fracture. Here we present a semi-analytical solution for a blade-shaped (PKN) geometry hydraulic fracture driven by a turbulent fluid in the limit of zero fluid leak-off to the formation. We model the turbulence in the PKN fracture using the Gaukler-Manning-Strickler parametrization, which relates the the flow rate of the water to the pressure gradient along the fracture. The key parameter in this relation is the Darcy-Weisbach friction factor for the roughness of the crack wall. Coupling this turbulence parametrization with conservation of mass allows us to write a nonlinear pde for the crack width as a function of space and time. By way of a similarity ansatz, we obtain a semi-analytical solution using an orthogonal polynomial series. Embedding the a...

  7. Hazards and Safeguards of High Pressure Hydraulic Fatigue Testing

    Science.gov (United States)

    1990-07-01

    rew e I&64aN neem mde tliF by block mumber) The creation and transfer of hydraulic pressure at the 690-MPa (100,000-psi) level is in itself hazardous...than alloy steel, we have found that it is more notch sensitive to fatigue and drastically degrades with small constituent variations. To avoid this...I ATTN: SMCWV-PP DIRECTOR, PRODUCT ASSURANCE DIRECTORATE 1 ATTN: SMCWV-QA NOTE: PLEASE NOTIFY DIRECTOR, BENET LABORATORIES, ATTN: SMCAR-CCB-TL, OF ANY

  8. Assessment of the Acute and Chronic Health Hazards of Hydraulic Fracturing Fluids.

    Science.gov (United States)

    Wattenberg, Elizabeth V; Bielicki, Jeffrey M; Suchomel, Ashley E; Sweet, Jessica T; Vold, Elizabeth M; Ramachandran, Gurumurthy

    2015-01-01

    There is growing concern about how hydraulic fracturing affects public health because this activity involves handling large volumes of fluids that contain toxic and carcinogenic constituents, which are injected under high pressure through wells into the subsurface to release oil and gas from tight shale formations. The constituents of hydraulic fracturing fluids (HFFs) present occupational health risks because workers may be directly exposed to them, and general public health risks because of potential air and water contamination. Hazard identification, which focuses on the types of toxicity that substances may cause, is an important step in the complex health risk assessment of hydraulic fracturing. This article presents a practical and adaptable tool for the hazard identification of HFF constituents, and its use in the analysis of HFF constituents reported to be used in 2,850 wells in North Dakota between December 2009 and November 2013. Of the 569 reported constituents, 347 could be identified by a Chemical Abstract Service Registration Number (CASRN) and matching constituent name. The remainder could not be identified either because of trade secret labeling (210) or because of an invalid CASRN (12). Eleven public databases were searched for health hazard information on thirteen health hazard endpoints for 168 identifiable constituents that had at least 25 reports of use. Health hazard counts were generated for chronic and acute endpoints, including those associated with oral, inhalation, ocular, and dermal exposure. Eleven of the constituents listed in the top 30 by total health hazard count were also listed in the top 30 by reports of use. This includes naphthalene, which along with benzyl chloride, has the highest health hazard count. The top 25 constituents reportedly used in North Dakota largely overlap with those reported for Texas and Pennsylvania, despite different geologic formations, target resources (oil vs. gas), and disclosure requirements

  9. Hydraulics.

    Science.gov (United States)

    Decker, Robert L.; Kirby, Klane

    This curriculum guide contains a course in hydraulics to train entry-level workers for automotive mechanics and other fields that utilize hydraulics. The module contains 14 instructional units that cover the following topics: (1) introduction to hydraulics; (2) fundamentals of hydraulics; (3) reservoirs; (4) lines, fittings, and couplers; (5)…

  10. Experimental Investigation on the Basic Law of Hydraulic Fracturing After Water Pressure Control Blasting

    Science.gov (United States)

    Huang, Bingxiang; Li, Pengfeng; Ma, Jian; Chen, Shuliang

    2014-07-01

    Because of the advantages of integrating water pressure blasting and hydraulic fracturing, the use of hydraulic fracturing after water pressure control blasting is a method that is used to fully transform the structure of a coal-rock mass by increasing the number and range of hydraulic cracks. An experiment to study hydraulic fracturing after water pressure blasting on cement mortar samples (300 × 300 × 300 mm3) was conducted using a large-sized true triaxial hydraulic fracturing experimental system. A traditional hydraulic fracturing experiment was also performed for comparison. The experimental results show that water pressure blasting produces many blasting cracks, and follow-up hydraulic fracturing forces blasting cracks to propagate further and to form numerous multidirectional hydraulic cracks. Four macroscopic main hydraulic cracks in total were noted along the borehole axial and radial directions on the sample surfaces. Axial and radial main failure planes induced by macroscopic main hydraulic cracks split the sample into three big parts. Meanwhile, numerous local hydraulic cracks were formed on the main failure planes, in different directions and of different types. Local hydraulic cracks are mainly of three types: local hydraulic crack bands, local branched hydraulic cracks, and axial layered cracks. Because local hydraulic cracks produce multiple local layered failure planes and lamellar ruptures inside the sample, the integrity of the sample decreases greatly. The formation and propagation process of many multidirectional hydraulic cracks is affected by a combination of water pressure blasting, water pressure of fracturing, and the stress field of the surrounding rock. To a certain degree, the stress field of surrounding rock guides the formation and propagation process of the blasting crack and the follow-up hydraulic crack. Following hydraulic fracturing that has been conducted after water pressure blasting, the integrity of the sample is found to

  11. 46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Hydraulic or pneumatic power and control-materials and... Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component (such as pipe runs, fittings, flanges, and standard valves) for hydraulic or pneumatic power and...

  12. 7 CFR 2902.28 - Stationary equipment hydraulic fluids.

    Science.gov (United States)

    2010-01-01

    ... formulated for use in stationary hydraulic equipment systems that have various mechanical parts, such as cylinders, pumps, valves, pistons, and gears, that are used for the transmission of power (and also...

  13. Optimization of Hydraulic Fracturing Fluid System in a Sand Oil Reservoir in Southwest of Iran

    Directory of Open Access Journals (Sweden)

    Reza Masoomi

    2015-10-01

    Full Text Available Fracturing fluid is one of the most important components of a hydraulic fracturing operation. Currently a lot of fluids are available for hydraulic fracturing. In order to selecting the most appropriate fracturing fluid for oil and gas wells with special characteristics, should be well understood fluid properties and should be informed about how changes in fluid properties to achieve the desired results. The aim of this study is optimization of viscosity and gel concentration in water base and foam base fluids which are used in hydraulic fracturing process in a sand oil reservoir in southwest of Iran. For this purpose various scenarios have been designed for various kinds of water base fluids and foam base fluids. Then the cumulative oil production has been estimated versus time and fracture half length. In addition the final required fracturing fluid and proppant have been determined for hydraulic fracturing in studied reservoir. Also in this study increasing the cumulative oil recovery in fractured and Non-fractured wells in a sand oil reservoir in southwest of Iran have been investigated.

  14. [Arterial pressure curve and fluid status].

    Science.gov (United States)

    Pestel, G; Fukui, K

    2009-04-01

    Fluid optimization is a major contributor to improved outcome in patients. Unfortunately, anesthesiologists are often in doubt whether an additional fluid bolus will improve the hemodynamics of the patient or not as excess fluid may even jeopardize the condition. This article discusses physiological concepts of liberal versus restrictive fluid management followed by a discussion on the respective capabilities of various monitors to predict fluid responsiveness. The parameter difference in pulse pressure (dPP), derived from heart-lung interaction in mechanically ventilated patients is discussed in detail. The dPP cutoff value of 13% to predict fluid responsiveness is presented together with several assessment techniques of dPP. Finally, confounding variables on dPP measurements, such as ventilation parameters, pneumoperitoneum and use of norepinephrine are also mentioned.

  15. Fluid driven fracture mechanics in highly anisotropic shale: a laboratory study with application to hydraulic fracturing

    Science.gov (United States)

    Gehne, Stephan; Benson, Philip; Koor, Nick; Enfield, Mark

    2017-04-01

    The finding of considerable volumes of hydrocarbon resources within tight sedimentary rock formations in the UK led to focused attention on the fundamental fracture properties of low permeability rock types and hydraulic fracturing. Despite much research in these fields, there remains a scarcity of available experimental data concerning the fracture mechanics of fluid driven fracturing and the fracture properties of anisotropic, low permeability rock types. In this study, hydraulic fracturing is simulated in a controlled laboratory environment to track fracture nucleation (location) and propagation (velocity) in space and time and assess how environmental factors and rock properties influence the fracture process and the developing fracture network. Here we report data on employing fluid overpressure to generate a permeable network of micro tensile fractures in a highly anisotropic shale ( 50% P-wave velocity anisotropy). Experiments are carried out in a triaxial deformation apparatus using cylindrical samples. The bedding planes are orientated either parallel or normal to the major principal stress direction (σ1). A newly developed technique, using a steel guide arrangement to direct pressurised fluid into a sealed section of an axially drilled conduit, allows the pore fluid to contact the rock directly and to initiate tensile fractures from the pre-defined zone inside the sample. Acoustic Emission location is used to record and map the nucleation and development of the micro-fracture network. Indirect tensile strength measurements at atmospheric pressure show a high tensile strength anisotropy ( 60%) of the shale. Depending on the relative bedding orientation within the stress field, we find that fluid induced fractures in the sample propagate in two of the three principal fracture orientations: Divider and Short-Transverse. The fracture progresses parallel to the bedding plane (Short-Transverse orientation) if the bedding plane is aligned (parallel) with the

  16. Mechanical testing of hydraulic fluids II; Mechanische Pruefung von Hydraulikfluessigkeiten II

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, M.; Feldmann, D.G.; Laukart, V.

    2001-09-01

    Since May 1996 the Institute for Mechanical Engineering Design 1 of Technical University of Hamburg-Harburg is working on the topic of ''Mechanical Testing of Hydraulic fluids''. The first project lasting 2 1/2 years was completed in 1999, the results are published as the DGMK report 514. Within these project a testing principle for the ''mechanical testing'' of hydraulic fluids has been derived, a prototype of a test rig was designed and set in operation at the authors' institute. This DGMK-report 514-1 describes the results of the second project, which investigates the operating behaviour of the test-rig more in detail. Several test-runs with a total number of 11 different hydraulic fluids show the dependence of the different lubricating behaviour of the tested fluids and their friction and wear behaviour during the tests in a reproducible way. The aim of the project was to derive a testing principle including the design of a suitable test-rig for the mechanical testing of hydraulic fluids. Based on the described results it can be stated that with the developed test it is possible to test the lubricity of hydraulic fluids reproducible and in correlation to field experiences within a relatively short time, so the target was reached. (orig.)

  17. A modified nodal pressure method for calculating flow distribution in hydraulic circuits for the case of unconventional closing relations

    Directory of Open Access Journals (Sweden)

    Egor M. Mikhailovsky

    2015-06-01

    Full Text Available We proposed a method for numerically solving the problem of flow distribution in hydraulic circuits with lumped parameters for the case of random closing relations. The conventional and unconventional types of relations for the laws of isothermal steady fluid flow through the individual hydraulic circuit components are studied. The unconventional relations are presented by those given implicitly by the flow rate and dependent on the pressure of the working fluid. In addition to the unconventional relations, the formal conditions of applicability were introduced. These conditions provide a unique solution to the flow distribution problem. A new modified nodal pressure method is suggested. The method is more versatile in terms of the closing relation form as compared to the unmodified one, and has lower computational costs as compared to the known technique of double-loop iteration. The paper presents an analysis of the new method and its algorithm, gives a calculated example of a gas transportation network, and its results.

  18. 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

  19. 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

    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...... to generate a controlled leakage  ow that aids in stabilising the system. The robustness of the system is then discussed in relation to dierent pilot line volumes and pump dynamics. Finally experimental results are presented, where the performance is compared to that of a similar hydraulic reference system...

  20. Time-dependent water permeation behavior of concrete under constant hydraulic pressure

    Institute of Scientific and Technical Information of China (English)

    Fang Yonghao; Wang Zhongli; Zhou Yue

    2008-01-01

    In the present work, a concrete permeability testing setup was designed to study the behavior of hydraulic concrete subjected to constant hydraulic pressure. The results show that when concrete is subjected to high enough constant hydraulic pressure, it will be permeated, and after it reaches its maximum permeation rate, the permeability coefficient will gradually decrease towards a stable value. A time-dependent model of permeability coefficient for concrete subjected to hydraulic pressure is proposed. It is indicated that the decrease of the permeability coefficient with permeation time conforms well to the negative-exponential decrease model.

  1. Effects of hydraulic pressure on the performance of single chamber air-cathode microbial fuel cells.

    Science.gov (United States)

    Cheng, Shaoan; Liu, Weifeng; Guo, Jian; Sun, Dan; Pan, Bin; Ye, Yaoli; Ding, Weijun; Huang, Haobin; Li, Fujian

    2014-06-15

    Scaling up of microbial fuel cells (MFCs) without losing power density requires a thorough understanding of the effect of hydraulic pressure on MFC performance. In this work, the performance of an activated carbon air-cathode MFC was evaluated under different hydraulic pressures. The MFC under 100 mmH2O hydraulic pressure produced a maximum power density of 1260 ± 24 mW m(-2), while the power density decreased by 24.4% and 44.7% as the hydraulic pressure increased to 500 mmH2O and 2000 mmH2O, respectively. Notably, the performance of both the anode and the cathode had decreased under high hydraulic pressures. Electrochemical impedance spectroscopy tests of the cathode indicated that both charge transfer resistance and diffusion transfer resistance increased with the increase in hydraulic pressure. Denaturing gradient gel electrophoresis of PCR-amplified partial 16S rRNA genes demonstrated that the similarity among anodic biofilm communities under different hydraulic pressures was ≥ 90%, and the communities of all MFCs were dominated by Geobacter sp. These results suggested that the reduction in power output of the single chamber air-cathode MFC under high hydraulic pressures can be attributed to water flooding of the cathode and suppression the metabolism of anodic exoelectrogenic bacteria.

  2. Integrated hydraulic cooler and return rail in camless cylinder head

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, Craig D [Clawson, MI; Neal, Timothy L [Ortonville, MI; Swain, Jeff L [Flushing, MI; Raimao, Miguel A [Colorado Springs, CO

    2011-12-13

    An engine assembly may include a cylinder head defining an engine coolant reservoir, a pressurized fluid supply, a valve actuation assembly, and a hydraulic fluid reservoir. The valve actuation assembly may be in fluid communication with the pressurized fluid supply and may include a valve member displaceable by a force applied by the pressurized fluid supply. The hydraulic fluid reservoir may be in fluid communication with the valve actuation assembly and in a heat exchange relation to the engine coolant reservoir.

  3. Effects of Hydraulic Frac Fluids on Subsurface Microbial Communities in Gas Shales

    Science.gov (United States)

    Jiménez, Núria; Krüger, Martin

    2014-05-01

    Shale gas is being considered as a complementary energy resource to coal or other fossil fuels. The exploitation of unconventional gas reservoirs requires the use of advanced drilling techniques and hydraulic stimulation (fracking). During fracking operations, large amounts of fluids (fresh water, proppants and chemical additives) are injected at high pressures into the formations, to produce fractures and fissures, and thus to release gas from the source rock into the wellbore. The injected fluids partly remain in the formation, while about 20 to 40% of the originally injected fluid flows back to the surface, together with formation waters, sometimes containing dissolved hydrocarbons, high salt concentrations, etc. The overall production operation will likely affect and be affected by subsurface microbial communities associated to the shale formations. On the one hand microbial activity (like growth, biofilm formation) can cause unwanted processes like corrosion, clogging, etc. On the other hand, the introduction of frac fluids could either enhance microbial growth or cause toxicity to the shale-associated microbial communities. To investigate the potential impacts of changing environmental reservoir conditions, like temperature, salinity, oxgen content and pH, as well as the introduction of frac or geogenic chemicals on subsurface microbial communities, laboratory experiments under in situ conditions (i.e. high temperatures and pressures) are being conducted. Enrichment cultures with samples from several subsurface environments (e.g. shale and coal deposits, gas reservoirs, geothermal fluids) have been set up using a variety of carbon sources, including hydrocarbons and typical frac chemicals. Classical microbiological and molecular analysis are used to determine changes in the microbial abundance, community structure and function after the exposure to different single frac chemicals, "artificial" frac fluids or production waters. On the other hand, potential

  4. Modulus-Pressure Equation for Confined Fluids

    CERN Document Server

    Gor, Gennady Y; Shen, Vincent K; Bernstein, Noam

    2016-01-01

    Ultrasonic experiments allow one to measure the elastic modulus of bulk solid or fluid samples. Recently such experiments have been carried out on fluid-saturated nanoporous glass to probe the modulus of a confined fluid. In our previous work [J. Chem. Phys., (2015) 143, 194506], using Monte Carlo simulations we showed that the elastic modulus $K$ of a fluid confined in a mesopore is a function of the pore size. Here we focus on modulus-pressure dependence $K(P)$, which is linear for bulk materials, a relation known as the Tait-Murnaghan equation. Using transition-matrix Monte Carlo simulations we calculated the elastic modulus of bulk argon as a function of pressure and argon confined in silica mesopores as a function of Laplace pressure. Our calculations show that while the elastic modulus is strongly affected by confinement and temperature, the slope of the modulus versus pressure is not. Moreover, the calculated slope is in a good agreement with the reference data for bulk argon and experimental data for ...

  5. Evolution of pore fluid pressures in a stimulated geothermal reservoir inferred from earthquake focal mechanisms

    Science.gov (United States)

    Terakawa, T.; Deichmann, N.

    2014-12-01

    We developed an inversion method to estimate the evolution of pore fluid pressure fields from earthquake focal mechanism solutions based on the Bayesian statistical inference and Akaike's Bayesian information criterion (ABIC). This method's application to induced seismicity in the Basel enhanced geothermal system in Switzerland shows the evolution of pore fluid pressures in response to fluid injection experiments. For a few days following the initiation of the fluid injection, overpressurized fluids are concentrated around the borehole and then anisotropically propagate within the reservoir until the bleed-off time. Then, the pore fluid pressure in the vicinity of the borehole drastically decreases, and overpressurized fluids become isolated in a few major fluid pockets. The pore fluid pressure in these pockets gradually decreases with time. The pore fluid pressure in the reservoir is less than the minimum principal stress at each depth, indicating that the hydraulic fracturing did not occur during stimulation. This suggests that seismic events may play an important role to promote the development of permeable channels, particularly southeast of the borehole where the largest seismic event (ML 3.4) occurred. This is not directly related to a drastic decrease in fault strength at the hypocenter, but rather the positive feedback between permeability enhancement and poro-elastic and stress transfer loading from slipping interfaces. These processes likely contribute to this event's nucleation.

  6. Understanding, Classifying, and Selecting Environmentally Acceptable Hydraulic Fluids

    Science.gov (United States)

    2016-08-01

    from renewable resources CRITERIA FOR ENVIRONMENTALLY ACCEPTABLE FLUIDS: The environmental factors for EA fluids are defined by the American...States Coast Guard (USCG), the United States Environmental Protection Agency (EPA), and the International Maritime Organization (IMO) provide specific...viscosity index • Lubricity • Pour point (point of oil solidification) • Wear protection (pump wear test, gear loading) • Foam • Air release • R

  7. POSSIBILITY OF HYDRAULIC FLUIDS WITH A LOW ENVIRONMENTAL IMPACT APPLICATION IN AGRICULTURE AND TRANSPORT MACHINERY

    Directory of Open Access Journals (Sweden)

    Marian Kučera

    2013-12-01

    Full Text Available Agricultural and transport equipment is ideally suited to use hydraulic oils. After engine oils, hydraulic fluids are the second most important group of lubricants. More than 85 % of these materials are currently mineral oil-based. In view of their high ecotoxicity and low biodegradability, mineral oil-based lubricants constitute a considerable threat to the environment. In contrast, most hydraulic fluids based on plant oils have a low environmental impact and are completely biodegradable. Moreover, lubricants based on plant oils display excellent tribological properties and generally have very high viscosity indices and flash points. For this reason, therefore, particularly soybean, sunflower and rapeseed seem to possess the relevant properties as a potential hydraulic fluid. There are several tribotechnical methods how to assess the current technical state of used lubricants (viscosity, water content, flash point, acidity. One of the modern methods how to detect wear particles is LaserNet Fines, which is a suitable technique for machine condition monitoring. The ageing of test oils is analysed by the Fourier transform infrared spectroscopy (FT-IR; for determining anti-wear properties of hydraulic oils, the standard STN EN ISO 20623:2004 indicates 1 hour under an applied load of 150 N. The objective of the paper is to show the description and examples of modern tribotechnical methods used for determination of the technical state of used biolubricants utilized in agriculture and transport machinery.

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

    Science.gov (United States)

    Dong, Xin; Lu, Hao; Huang, Houxu; Hao, Yiqing; Xia, Yuanpu

    2017-06-01

    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.

  9. 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.

  10. Application of computational fluid dynamic to model the hydraulic performance of subsurface flow wetlands

    Institute of Scientific and Technical Information of China (English)

    FAN Liwei; Hai Reti; WANG Wenxing; LU Zexiang; YANG Zhiming

    2008-01-01

    A subsurface flow wetland (SSFW) was simulated using a commercial computational fluid dynamic (CFD) code. The constructed media was simulated using porous media and the liquid resident time distribution (RTD) in the SSFW was obtained using the particle trajectory model. The effect of wetland configuration and operating conditions on the hydraulic performance of the SSFW were investigated. The results indicated that the hydraulic performance of the SSFW was predominantly affected by the wetland configuration. The hydraulic efficiency of the SSFW with an inlet at the middle edge of the upper media was 0.584 and the best among the SSFWs with an inlet at the top, the middle, and the bottom edge of the upper media. The constructed media affected the hydraulic performance by the ratio (K) of the upper and lower media resistance. The selection of appropriate media resistance in the protection layer can improve the hydraulic efficiency. When the viscous resistance coefficient of the media in the protection layer changed from 2.315×105 to 1.200×108, the hydraulic efficiency of the SSFW increased from 0.301 to 0.751. However, the effect of operating conditions on the hydraulic efficiency of the SSFW was slight.

  11. Influence of Concentration and Salinity on the Biodegradability of Organic Additives in Hydraulic Fracturing Fluid

    Science.gov (United States)

    Mouser, P. J.; Kekacs, D.

    2014-12-01

    One of the risks associated with the use of hydraulic fracturing technologies for energy development is the potential release of hydraulic fracturing-related fluids into surface waters or shallow aquifers. Many of the organic additives used in hydraulic fracturing fluids are individually biodegradable, but little is know on how they will attenuate within a complex organic fluid in the natural environment. We developed a synthetic hydraulic fracturing fluid based on disclosed recipes used by Marcellus shale operators to evaluate the biodegradation potential of organic additives across a concentration (25 to 200 mg/L DOC) and salinity gradient (0 to 60 g/L) similar to Marcellus shale injected fluids. In aerobic aqueous solutions, microorganisms removed 91% of bulk DOC from low SFF solutions and 57% DOC in solutions having field-used SFF concentrations within 7 days. Under high SFF concentrations, salinity in excess of 20 g/L inhibited organic compound biodegradation for several weeks, after which time the majority (57% to 75%) of DOC remained in solution. After SFF amendment, the initially biodiverse lake or sludge microbial communities were quickly dominated (>79%) by Pseudomonas spp. Approximately 20% of added carbon was converted to biomass while the remainder was respired to CO2 or other metabolites. Two alcohols, isopropanol and octanol, together accounted for 2-4% of the initial DOC, with both compounds decreasing to below detection limits within 7 days. Alcohol degradation was associated with an increase in acetone at mg/L concentrations. These data help to constrain the biodegradation potential of organic additives in hydraulic fracturing fluids and guide our understanding of the microbial communities that may contribute to attenuation in surface waters.

  12. Development of a Test Apparatus for Measurement of Hydraulic Fluid Efficiency

    Institute of Scientific and Technical Information of China (English)

    Matt Jackson; Brian Koehler

    2011-01-01

    With increasing demand for nonrenewable resources,energy conservation is critical.Efficiency gains allow more work to be performed while maintaining or even decreasing the energy expended in the process.Reducing the energy consumed by a system results in favorable economic and environmental impact.An apparatus has been developed to measure hydraulic fluid efficiency in a stationary application.The system can be used to develop more efficient fluids,leading to increased work output or decreased energy consumption.

  13. Computational Fluid Dynamics Modelling of Hydraulics and Sedimentation in Process Reactors During Aeration Tank Settling

    DEFF Research Database (Denmark)

    Dam Jensen, Mette; Ingildsen, Pernille; Rasmussen, Michael R.;

    2005-01-01

    shown to be more effective than others. To improve the design of less effective plants Computational Fluid Dynamics (CFD) modelling of hydraulics and sedimentation has been applied. The paper discusses the results at one particular plant experiencing problems with partly short-circuiting of the inlet...... been suggested and tested by means of computational fluid dynamics modelling. The most promissing design change have been found and reported....

  14. 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......Currently mobile hydraulics is in a transition phase, where electronic sensors and digital signal processors are becoming standard on a high number of machines, hereby replacing hydraulic pilot lines and offering new possibilities with regard to both control and feasibility. As most open...... displacement pump based on an electrical reference. The paper first presents the considered system and an experimentally verified model of this. A linearized model and a stability analysis is then presented, based on which an H∞control strategy is selected. A nominal performance and a robustly stable...

  15. 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...... displacement pump based on an electrical reference. The paper first presents the considered system and an experimentally verified model of this. A linearized model and a stability analysis is then presented, based on which an H∞control strategy is selected. A nominal performance and a robustly stable...

  16. Particle-based simulation of hydraulic fracture and fluid/heat flow in geothermal reservoirs

    Science.gov (United States)

    Mora, Peter; Wang, Yucang; Alonso-Marroquin, Fernando

    2013-06-01

    Realizing the potential of geothermal energy as a cheap, green, sustainable resource to provide for the planet's future energy demands that a key geophysical problem be solved first: how to develop and maintain a network of multiple fluid flow pathways for the time required to deplete the heat within a given region. We present the key components for micro-scale particle-based numerical modeling of hydraulic fracture, and fluid and heat flow in geothermal reservoirs. They are based on the latest developments of ESyS-Particle - the coupling of the Lattice Solid Model (LSM) to simulate the nonlinear dynamics of complex solids with the Lattice Boltzmann Method (LBM) applied to the nonlinear dynamics of coupled fluid and heat flow in the complex solid-fluid system. The coupled LSM/LBM can be used to simulate development of fracture systems in discontinuous media, elastic stress release, fluid injection and the consequent slip at joint surfaces, and hydraulic fracturing; heat exchange between hot rocks and water within flow pathways created through hydraulic fracturing; and fluid flow through complex, narrow, compact and gouge-or powder-filled fracture and joint systems. We demonstrate the coupled LSM/LBM to simulate the fundamental processes listed above, which are all components for the generation and sustainability of the hot-fractured rock geothermal energy fracture systems required to exploit this new green-energy resource.

  17. Numerical Modeling of a Thermal-Hydraulic Loop and Test Section Design for Heat Transfer Studies in Supercritical Fluids

    Science.gov (United States)

    McGuire, Daniel

    A numerical tool for the simulation of the thermal dynamics of pipe networks with heat transfer has been developed with the novel capability of modeling supercritical fluids. The tool was developed to support the design and deployment of two thermal-hydraulic loops at Carleton University for the purpose of heat transfer studies in supercritical and near-critical fluids. First, the system was characterized based on its defining features; the characteristic length of the flow path is orders of magnitude larger than the other characteristic lengths that define the system's geometry; the behaviour of the working fluid in the supercritical thermodynamic state. An analysis of the transient thermal behaviour of the model's domains is then performed to determine the accuracy and range of validity of the modeling approach for simulating the transient thermal behaviour of a thermal-hydraulic loop. Preliminary designs of three test section geometries, for the purpose of heat transfer studies, are presented in support of the overall design of the Carleton supercritical thermal-hydraulic loops. A 7-rod-bundle, annular and tubular geometries are developed with support from the new numerical tool. Materials capable of meeting the experimental requirements while operating in supercritical water are determined. The necessary geometries to satisfy the experimental goals are then developed based on the material characteristics and predicted heat transfer behaviour from previous simulation results. An initial safety analysis is performed on the test section designs, where they are evaluated against the ASME Boiler, Pressure Vessel, and Pressure Piping Code standard, required for safe operation and certification.

  18. Reducing pressure oscillations in discrete fluid power systems

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

    2016-01-01

    Discrete fluid power systems featuring transmission lines inherently include pressure oscillations. Experimental verification of a discrete fluid power power take off system for wave energy converters has shown the cylinder pressure to oscillate as force shifts are performed. This article...

  19. Evaluation of Biobased Hydraulic Fluids in Military Construction Equipment

    Science.gov (United States)

    2007-10-31

    instead of the petroleum sources. Their biodegradability is comparable to vegetable oils and the lubrication properties are very similar to mineral ...Ni, Mg, Cu, and Zn) were analyzed. Unlike the petroleum based fluids, the BHFs evaluated did not contain organo - metal additives. However, field

  20. Porphyry-copper ore shells form at stable pressure-temperature fronts within dynamic fluid plumes.

    Science.gov (United States)

    Weis, P; Driesner, T; Heinrich, C A

    2012-12-21

    Porphyry-type ore deposits are major resources of copper and gold, precipitated from fluids expelled by crustal magma chambers. The metals are typically concentrated in confined ore shells within vertically extensive vein networks, formed through hydraulic fracturing of rock by ascending fluids. Numerical modeling shows that dynamic permeability responses to magmatic fluid expulsion can stabilize a front of metal precipitation at the boundary between lithostatically pressured up-flow of hot magmatic fluids and hydrostatically pressured convection of cooler meteoric fluids. The balance between focused heat advection and lateral cooling controls the most important economic characteristics, including size, shape, and ore grade. This self-sustaining process may extend to epithermal gold deposits, venting at active volcanoes, and regions with the potential for geothermal energy production.

  1. Supercritical Fluid Chromatography, Pressurized Liquid Extraction and Supercritical Fluid Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Henry, Matthew C.; Yonker, Clement R.

    2006-06-15

    In this review we examine the related fields of supercritical fluid chromatography (SFC) and supercritical fluid extraction (SFE). We reviewed the published literature in the period from November 2003 to November 2005. Well over 300 papers were published in this period. This large body of work indicates continuing active growth of the field, but an exhaustive review is beyond the scope of this work. We have chosen to include a sampling of publications that best represent the continuing trends and new ideas in the field. In keeping with past reviews on this subject1, we have broadened our scope to include fluid systems operating at high temperature and pressure, but below the critical point. Various terms have been applied to this state: sub-critical fluid extraction, pressurized liquid extraction, and accelerated solvent extraction. The term accelerated solvent extraction has been used by instrument manufacturers to refer to this process, but we will use the more descriptive term pressurized liquid extraction (PLE) to refer to these systems. Most of the research in the field is of an “evolutionary” rather than “revolutionary” nature. As in the previous review period, applications papers make up a majority of the published work. Pharmaceutical applications continue to be a strong theme. Most of the pharmaceutical work has centered on preparative, rather than analytical, separations. Chiral separations are an exception, as analytical scale separations of chiral compounds are an area of intense interest. Food and natural products represent the next largest body of work. Major themes are the isolation and characterization of high-value added foodstuffs, fragrances, and flavor compounds from novel natural materials or agricultural by-products. The areas of food, natural products, and pharmaceutical separation science converge in the area of so-called nutraceuticals. These are typically high-value products, either sold alone or as part of a fortified food, that

  2. 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.

  3. Pressure transfer functions for interfacial fluid problems

    CERN Document Server

    Chen, Robin Ming; Walsh, Samuel

    2015-01-01

    We make a consistent derivation, from the governing equations, of the pressure transfer function in the small-amplitude Stokes wave regime and the hydrostatic approximation in the small-amplitude solitary water wave regime, in the presence of a background shear flow. The results agree with the well-known formulae in the zero vorticity case,but they incorporate the effects of vorticity through solutions to the Rayleigh equation. We extend the results to permit continuous density stratification and to internal waves between two constant-density fluids. Several examples are discussed.

  4. Modelling of a hydraulic engine mount with fluid-structure interaction finite element analysis

    Science.gov (United States)

    Shangguan, Wen-Bin; Lu, Zhen-Hua

    2004-08-01

    Hydraulic engine mount (HEM) is now widely used as a highly effective vibration isolator in automotive powertrain. A lumped parameter (LP) model is a traditional model for modelling the dynamic characteristics of HEM, in which the system parameters are usually obtained by experiments. In this paper, a fluid-structure interaction (FSI) finite element analysis (FEA) method and a non-linear FEA technology are used to determine the system parameters, and a fully coupled FSI model is developed for modelling the static and lower-frequency performance of an HEM. A FSI FEA technique is used to estimate the parameters of volumetric compliances, equivalent piston area, inertia and resistance of the fluid in the inertia track and the decoupler of an HEM. A non-linear FEA method is applied to determine the dynamic stiffness of rubber spring of the HEM. The system parameters predicated by FEA are compared favorably with experimental data and/or analytical solutions. A numerical simulation for an HEM with an inertia track and a free decoupler is performed based on the FSI model and the LP model along with the estimated system parameters, and again the simulation results are compared with experimental data. The calculated time histories of some variables in the model, such as the pressure in the upper chamber, the displacement of the free decoupler and the volume flow through the inertia track and the decoupler, under different excitations, elucidate the working mechanism of the HEM. The pressure distribution calculated with the FSI model in the chambers of the HEM validates the assumption that the pressure distribution in the upper and lower chamber is uniform in the LP model. The work conducted in the paper demonstrates that the methods for estimating the system parameters in the LP model and the FSI model for modelling HEM are effective, with which the dynamic characteristic analysis and design optimization of an HEM can be performed before its prototype development, and this

  5. Fluid-loss control for high-permeability rocks in hydraulic fracturing under realistic shear conditions

    Energy Technology Data Exchange (ETDEWEB)

    Navarrete, R.C.; Mitchell, J.P.

    1995-12-31

    A study is presented on the effectiveness of different combinations of fluid and fluid-loss additives to control fluid loss in high-permeability formations under high shear rates. The impact on matrix damage and proppant-pack damage is also studied. Borate-crosslinked guars, hydroxyethylcellulose (HEC) and a surfactant water-base gravel packing fluid were investigated. The fluid-loss additive considered was silica flour. All fluid-loss tests were run in dynamic fluid-loss cells. To properly test high-permeability cores, new long core dynamic fluid-loss cells were used. The matrix damage caused by the invasion of the fluid was determined using pressure taps along the core. Conductivity tests were also run to determine the damage to the proppant pack. Results show that the effectiveness of particulate fluid-loss additives under dynamic conditions is strongly dependent on the initial leakoff rate, which depends on the pressure gradient across the core, permeability of the core and viscosity of the invading fluid. The use of silica flour helps matrix flowback, and it has a minimal effect on proppant-pack conductivity in clean fluids (e.g., surfactant water-base gravel packing fluid). With the exception of the borate-crosslinked guar with no fluid-loss additive, the variety of fluids used in these tests (with and without silica flour) have a negligible effect on postproduction.

  6. Comparison of hydraulic and hemolytic properties of different impeller designs of an implantable rotary blood pump by computational fluid dynamics.

    Science.gov (United States)

    Arvand, Arash; Hahn, Nicole; Hormes, Marcus; Akdis, Mustafa; Martin, Michael; Reul, Helmut

    2004-10-01

    A mixed-flow blood pump for long-term applications has been developed at the Helmholtz-Institute in Aachen, Germany. Central features of this implantable pump are a centrally integrated motor, a blood-immersed mechanical bearing, magnetic coupling of the impeller, and a shrouded impeller, which allows a relatively wide clearance. The aim of the study was a numerical analysis of hydraulic and hemolytic properties of different impeller design configurations. In vitro testing and numerical simulation techniques (computational fluid dynamics [CFD]) were applied to achieve a comprehensive overview. Pressure-flow charts were experimentally measured in a mock loop in order to validate the CFD data. In vitro hemolysis tests were performed at the main operating point of each impeller design. General flow patterns, pressure-flow charts, secondary flow rates, torque, and axial forces on the impeller were calculated by means of CFD. Furthermore, based on streak line techniques, shear stress (stress loading), exposure times, and volume percentage with critical stress loading have been determined. Comparison of CFD data with pressure head measurements showed excel-lent agreement. Also, impressive trend conformity was observed between in-vitro hemolysis results and numerical data. Comparison of design variations yielded clear trends and results. Design C revealed the best hydraulic and hemolytic properties and was chosen as the final design for the mixed-flow rotary blood pump.

  7. Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based Hydraulic Fracturing in Shale Gas Systems and Electromagnetic Geophysical Monitoring of Fluid Migration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jihoon; Um, Evan; Moridis, George

    2014-12-01

    We investigate fracture propagation induced by hydraulic fracturing with water injection, using numerical simulation. For rigorous, full 3D modeling, we employ a numerical method that can model failure resulting from tensile and shear stresses, dynamic nonlinear permeability, leak-off in all directions, and thermo-poro-mechanical effects with the double porosity approach. Our numerical results indicate that fracture propagation is not the same as propagation of the water front, because fracturing is governed by geomechanics, whereas water saturation is determined by fluid flow. At early times, the water saturation front is almost identical to the fracture tip, suggesting that the fracture is mostly filled with injected water. However, at late times, advance of the water front is retarded compared to fracture propagation, yielding a significant gap between the water front and the fracture top, which is filled with reservoir gas. We also find considerable leak-off of water to the reservoir. The inconsistency between the fracture volume and the volume of injected water cannot properly calculate the fracture length, when it is estimated based on the simple assumption that the fracture is fully saturated with injected water. As an example of flow-geomechanical responses, we identify pressure fluctuation under constant water injection, because hydraulic fracturing is itself a set of many failure processes, in which pressure consistently drops when failure occurs, but fluctuation decreases as the fracture length grows. We also study application of electromagnetic (EM) geophysical methods, because these methods are highly sensitive to changes in porosity and pore-fluid properties due to water injection into gas reservoirs. Employing a 3D finite-element EM geophysical simulator, we evaluate the sensitivity of the crosswell EM method for monitoring fluid movements in shaly reservoirs. For this sensitivity evaluation, reservoir models are generated through the coupled flow

  8. A Geochemical Framework for Evaluating Shale-Hydraulic Fracture Fluid Interactions

    Science.gov (United States)

    Harrison, A. L.; Jew, A. D.; Dustin, M. K.; Joe-Wong, C. M.; Thomas, D.; Maher, K.; Brown, G. E.; Bargar, J.; Bill, M.; Conrad, M. E.

    2015-12-01

    The development of shale oil and gas reservoirs has increased dramatically due to the application of hydraulic fracturing techniques. Fracture fluids contain dissolved oxygen and numerous chemical additives [1] that are out of equilibrium with the reducing conditions in shale reservoirs and could react extensively with shale minerals and alter porosity. Yet, the complex dissolution-precipitation reactions in shales along with the poorly constrained characteristics of many fracture fluid additives hinder predictive modeling based on established reaction kinetics and thermodynamic constants [2]. Here, we are developing a reaction framework to better predict reaction progress and porosity evolution upon exposure of shales to hydraulic fracturing fluids. To this end, the reactive transport model CrunchFlow [3] was applied to the results of batch reactor experiments containing shales of different mineralogical and organic compositions exposed to simulated fracturing fluid. Despite relatively good agreement between modeled and experimental data for pH and aqueous Ca concentrations, which are strongly governed by carbonate dissolution, the model is presently unable to reproduce observed trends in aqueous Fe concentration. This is largely attributable to the dearth of thermodynamic data for certain fracture fluid components and the complex interactions between multiple Fe-bearing mineral phases. Experimental results revealed that the presence of organic fracture fluid components strongly influenced the precipitation of Fe-bearing phases, which are speculated to coat fracture fluid polymers that formed in the reactors. The incorporation of these effects in our reactive transport model will permit improved prediction of reservoir permeability evolution and metal release during hydraulic fracturing operations. [1] Stringfellow et al. (2014) J. Hazard. Mater. [2] Carroll et al. (2013) Environ. Sci. Technol. [3] Steefel and Maher (2009) Rev. Mineral. Geochem.

  9. Estimation of changes in dynamic hydraulic force in a magnetically suspended centrifugal blood pump with transient computational fluid dynamics analysis.

    Science.gov (United States)

    Masuzawa, Toru; Ohta, Akiko; Tanaka, Nobuatu; Qian, Yi; Tsukiya, Tomonori

    2009-01-01

    The effect of the hydraulic force on magnetically levitated (maglev) pumps should be studied carefully to improve the suspension performance and the reliability of the pumps. A maglev centrifugal pump, developed at Ibaraki University, was modeled with 926 376 hexahedral elements for computational fluid dynamics (CFD) analyses. The pump has a fully open six-vane impeller with a diameter of 72.5 mm. A self-bearing motor suspends the impeller in the radial direction. The maximum pressure head and flow rate were 250 mmHg and 14 l/min, respectively. First, a steady-state analysis was performed using commercial code STAR-CD to confirm the model's suitability by comparing the results with the real pump performance. Second, transient analysis was performed to estimate the hydraulic force on the levitated impeller. The impeller was rotated in steps of 1 degrees using a sliding mesh. The force around the impeller was integrated at every step. The transient analysis revealed that the direction of the radial force changed dynamically as the vane's position changed relative to the outlet port during one circulation, and the magnitude of this force was about 1 N. The current maglev pump has sufficient performance to counteract this hydraulic force. Transient CFD analysis is not only useful for observing dynamic flow conditions in a centrifugal pump but is also effective for obtaining information about the levitation dynamics of a maglev pump.

  10. Temperature induced pore fluid pressurization in geomaterials

    CERN Document Server

    Ghabezloo, Siavash

    2010-01-01

    The theoretical basis of the thermal response of the fluid-saturated porous materials in undrained condition is presented. It has been demonstrated that the thermal pressurization phenomenon is controlled by the discrepancy between the thermal expansion of the pore fluid and of the solid phase, the stress-dependency of the compressibility and the non-elastic volume changes of the porous material. For evaluation of the undrained thermo-poro-elastic properties of saturated porous materials in conventional triaxial cells, it is important to take into account the effect of the dead volume of the drainage system. A simple correction method is presented to correct the measured pore pressure change and also the measured volumetric strain during an undrained heating test. It is shown that the porosity of the tested material, its drained compressibility and the ratio of the volume of the drainage system to the one of the tested sample, are the key parameters which influence the most the error induced on the measuremen...

  11. 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)

  12. Analysis on the Pressure Fluctuation Law of a Hydraulic Exciting System with a Wave-exciter

    Institute of Scientific and Technical Information of China (English)

    WEI Xiu-ye; KOU Zi-ming; LU Zi-rong

    2011-01-01

    A hydraulic exciting system with a wave exciter has been constructed in order to study the hydraulic vibra- tion law. The system consists of an oil source, wave-exciter and oil cylinder, and is controlled by a wave-exciter. The working principle of the hydraulic exciting system and wave exciter has been analyzed, and its excitation process has been illustrated. The law of every pipe's pressure fluctuation of the system is obtained by experiment. The theo- retical analysis and experimental data prove that the pipeline pressure periodically changes and the pipeline pressure fluctuation frequency is independently controlled by the excitation frequency of the wave-exciter. Every pipelinc's pressure wave is produced by system flow fluctuation and water hammer coupling. The pressure fluctuation rules of the system provide a theoretical basis for the study of the associated liberation system.

  13. Vegetable oils as hydraulic fluids for agricultural applications

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, G.; Igartua, A.; Fernandez-Diaz, B.; Urquiola, F.; Vivanco, S.; Arguizoniz, R.

    2011-07-01

    The formulation of environmentally friendly lubricants following the criterion of the European EcoLabel is expensive owing to the lack of technological development in this area. The present work deals with the development of lubricant formulations from vegetable oils, in particular using high oleic sunflower oil as base fluid. These new biolubricants have to perform as good as the reference lubricants used in the real application (an agricultural tractor) but with the additional condition and value of their biodegradability without toxicity. Formulation development has been performed by Verkol Lubricantes, involving the selection of the base oil and the design of the additive package. The investigation performed by Tekniker in the laboratory has covered different aspects, characterizing the most important physicochemical properties of the lubricants, including their behavior at low temperatures and their resistance to oxidation. The ribological properties of the new biolubricants have also been studied, analyzing their ability to protect the interacting surface from wear, as well as the level of friction generated during sliding. Moreover, the compatibility of the new formulated oil with all the seals present in the real application has been taken into consideration. The selected lubricant is now being tested in agricultural machinery from AGRIA. (Author).

  14. Pressure regulation in nonlinear hydraulic networks by positive controls

    NARCIS (Netherlands)

    De Persis, Claudio; Skovmose Kallesøe, Carsten

    2009-01-01

    We report on our investigation of an industrial case study of a system distributed over a network, namely a large-scale hydraulic network which underlies a district heating system. The network comprises an arbitrarily large number of end-users and actuators distributed along the network. After intro

  15. Hydraulic fluids and jet engine oil: pyrolysis and aircraft air quality.

    Science.gov (United States)

    van Netten, C; Leung, V

    2001-01-01

    Incidents of smoke in aircraft cabins often result from jet engine oil and/or hydraulic fluid that leaks into ventilation air, which can be subjected to temperatures that exceed 500 degrees C. Exposed flight-crew members have reported symptoms, including dizziness, nausea, disorientation, blurred vision, and tingling in the legs and arms. In this study, the authors investigated pyrolysis products of one jet engine oil and two hydraulic fluids at 525 degrees C. Engine oil was an important source of carbon monoxide. Volatile agents and organophosphate constituents were released from all the agents tested; however, the neurotoxin trimethyl propane phosphate was not found. The authors hypothesized that localized condensation of pyrolysis products in ventilation ducts, followed by mobilization when cabin heat demand was high, accounted for mid-flight incidents. The authors recommended that carbon monoxide data be logged continuously to capture levels during future incidents.

  16. Extensive use of computational fluid dynamics in the upgrading of hydraulic turbines

    Energy Technology Data Exchange (ETDEWEB)

    Sabourin, M.; Eremeef, R.; De Henau, V.

    1995-12-31

    Computational fluid dynamics codes, based on turbulent Navier-Stokes equations, allow evaluation of the hydraulic losses of each turbine component with precision. Using those codes with the new generation of computers enables a wide variety of component geometries to be modelled and compared to the original designs under flow conditions obtained from testing, at a reasonable cost and in a relatively short time. This paper reviews the actual method used in the design of a solution to a turbine rehabilitation project involving runner replacement, redesign of upstream components (stay vanes and wicket gates), and downstream components (draft tubes and runner outlets). The paper shows how computational fluid dynamics can help hydraulic engineers to obtain valuable information not only on performance enhancement but also on the phenomena that produce the enhancement, and to reduce the variety of modifications to be tested.

  17. Potential Impacts of Spilled Hydraulic Fracturing Fluid Chemicals on Water Resources: Types, volumes, and physical-chemical properties of chemicals

    Science.gov (United States)

    Hydraulic fracturing (HF) fluid chemicals spilled on-site may impact drinking water resources. While chemicals generally make up <2% of the total injected fluid composition by mass, spills may have undiluted concentrations. HF fluids typically consist of a mixture of base flui...

  18. Computational fluid dynamics-based hydraulic and hemolytic analyses of a novel left ventricular assist blood pump.

    Science.gov (United States)

    Yang, Xiao-Chen; Zhang, Yan; Gui, Xing-Min; Hu, Sheng-Shou

    2011-10-01

    The advent of various technologies has allowed mechanical blood pumps to become more reliable and versatile in recent decades. In our study group, a novel structure of axial flow blood pump was developed for assisting the left ventricle. The design point of the left ventricular assist blood pump 25 (LAP-25) was chosen at 4 Lpm with 100 mm Hg according to our clinical practice. Computational fluid dynamics was used to design and analyze the performance of the LAP-25. In order to obtain a required hydraulic performance and a satisfactory hemolytic property in the LAP-25 of a smaller size, a novel structure was developed including an integrated shroud impeller, a streamlined impeller hub, and main impeller blades with splitter blades; furthermore, tandem cascades were introduced in designing the diffuser. The results of numerical simulation show the LAP-25 can generate flow rates of 3-5 Lpm at rotational speeds of 8500-10,500 rpm, producing pressure rises of 27.5-148.3 mm Hg with hydraulic efficiency points ranging from 13.4 to 27.5%. Moreover, the fluid field and the hemolytic property of the LAP-25 were estimated, and the mean hemolysis index of the pump was 0.0895% with Heuser's estimated model. In conclusion, the design of the LAP-25 shows an acceptable result.

  19. WORKING LIQUID PRESSURE AND ITS CONTROL IN HYDRAULIC DRAWING PROCESSES OF CUPS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A method of setting up a pressure-stroke characteristic of the working liquid in hydraulic drawing is studied. A pressure-stroke characteristic and software for controlling its forming process are also developed. And a set of pressure controlling devices with PLC as a central processor are designed. It can be got from the relevant experiments that the pressure-stroke characteristic is correct and its control for forming process is available.

  20. Microbial Community Changes in Hydraulic Fracturing Fluids and Produced Water from Shale Gas Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Arvind Murali; Hartsock, Angela; Bibby, Kyle J; Hammack, Richard W; Vidic, Radisav D; Gregory, Kelvin B

    2013-11-19

    Microbial communities associated with produced water from hydraulic fracturing are not well understood, and their deleterious activity can lead to significant increases in production costs and adverse environmental impacts. In this study, we compared the microbial ecology in prefracturing fluids (fracturing source water and fracturing fluid) and produced water at multiple time points from a natural gas well in southwestern Pennsylvania using 16S rRNA gene-based clone libraries, pyrosequencing, and quantitative PCR. The majority of the bacterial community in prefracturing fluids constituted aerobic species affiliated with the class Alphaproteobacteria. However, their relative abundance decreased in produced water with an increase in halotolerant, anaerobic/facultative anaerobic species affiliated with the classes Clostridia, Bacilli, Gammaproteobacteria, Epsilonproteobacteria, Bacteroidia, and Fusobacteria. Produced water collected at the last time point (day 187) consisted almost entirely of sequences similar to Clostridia and showed a decrease in bacterial abundance by 3 orders of magnitude compared to the prefracturing fluids and produced water samplesfrom earlier time points. Geochemical analysis showed that produced water contained higher concentrations of salts and total radioactivity compared to prefracturing fluids. This study provides evidence of long-term subsurface selection of the microbial community introduced through hydraulic fracturing, which may include significant implications for disinfection as well as reuse of produced water in future fracturing operations.

  1. Vegetable oils as hydraulic fluids for agricultural applications

    Directory of Open Access Journals (Sweden)

    Mendoza, G.

    2011-03-01

    Full Text Available The formulation of environmentally friendly lubricants following the criterion of the European EcoLabel is expensive owing to the lack of technological development in this area. The present work deals with the development of lubricant formulations from vegetable oils, in particular using high oleic sunflower oil as base fluid. These new biolubricants have to perform as good as the reference lubricants used in the real application (an agricultural tractor but with the additional condition and value of their biodegradability without toxicity. Formulation development has been performed by Verkol Lubricantes, involving the selection of the base oil and the design of the additive package. The investigation performed by Tekniker in the laboratory has covered different aspects, characterizing the most important physicochemical properties of the lubricants, including their behavior at low temperatures and their resistance to oxidation. The tribological properties of the new biolubricants have also been studied, analyzing their ability to protect the interacting surface from wear, as well as the level of friction generated during sliding. Moreover, the compatibility of the new formulated oil with all the seals present in the real application has been taken into consideration. The selected lubricant is now being tested in agricultural machinery from AGRIA.

    La formulación de lubricantes amigables con el medioambiente siguiendo los criterios Europeos de la EcoLabel resulta cara debido a la falta de desarrollo tecnológico en esta área. En el presente trabajo se han desarrollado formulaciones de lubricantes a partir de aceites de origen vegetal, en particular empleando como aceite base el GAO (Girasol de Alto Oleico. Estos nuevos lubricantes deben presentar un comportamiento tan bueno como el de los lubricantes de referencia empleados en la aplicación real (un tractor agrícola, pero con la condición y valor añadido de ser biodegradables y no t

  2. Numerical and experimental study of low-frequency pressure pulsations in hydraulic units with Francis turbine

    Science.gov (United States)

    Platonov, D.; Minakov, A.; Dekterev, D.; Sentyabov, A.; Dekterev, A.

    2016-10-01

    The paper presents the numerical simulation method of three-dimensional turbulent flows in the hydraulic turbine. This technique was verified by means of experimental data obtained on a water model of the Francis turbines. An aerodynamic stand, which is a miniature copy of the real hydraulic turbine, was designed. A series of experiments have been carried out on this stand and the corresponding calculations were performed. The dependence of the velocity and pressure pulsations profiles for different operation regimes are presented.

  3. Replacement of petroleum based hydraulic fluids with a soybean-based alternative

    Energy Technology Data Exchange (ETDEWEB)

    Rose, B.; Rivera, P.

    1998-05-01

    Despite the best preventative measures, ruptured hoses, spills and leaks occur with use of all hydraulic equipment. Although these releases do not usually produce a RCRA regulated waste, they are often a reportable occurrence. Clean-up and subsequent administrative procedure involves additional costs, labor and work delays. Concerns over these releases, especially related to Sandia National Laboratories (SNL) vehicles hauling waste on public roads prompted Fleet Services (FS) to seek an alternative to the standard petroleum based hydraulic fluid. Since 1996 SNL has participated in a pilot program with the University of Iowa (UNI) and selected vehicle manufacturers, notably John Deere, to field test hydraulic fluid produced from soybean oil in twenty of its vehicles. The vehicles included loaders, graders, sweepers, forklifts and garbage trucks. Research was conducted for several years at UNI to modify and market soybean oils for industrial uses. Soybean oil ranks first in worldwide production of vegetable oils (29%), and represents a tremendous renewable resource. Initial tests with soybean oil showed excellent lubrication and wear protection properties. Lack of oxidative stability and polymerization of the oil were concerns. These concerns were being addressed through genetic alteration, chemical modification and use of various additives, and the improved lubricant is in the field testing stage.

  4. Controlled differential pressure system for an enhanced fluid blending apparatus

    Science.gov (United States)

    Hallman, Jr., Russell Louis

    2009-02-24

    A system and method for producing a controlled blend of two or more fluids. Thermally-induced permeation through a permeable tube is used to mix a first fluid from outside the tube with a second fluid flowing through the tube. Mixture ratios may be controlled by adjusting the temperature of the first fluid or by adjusting the pressure drop through the permeable tube. The combination of a back pressure control valve and a differential regulator is used to control the output pressure of the blended fluid. The combination of the back pressure control valve and differential regulator provides superior flow control of the second dry gas. A valve manifold system may be used to mix multiple fluids, and to adjust the volume of blended fluid produced, and to further modify the mixture ratio.

  5. Methodology to predict friction pressure drop in drilling fluid flows; Metodologia para previsao de perdas de carga em escoamentos de fluidos de perfuracao

    Energy Technology Data Exchange (ETDEWEB)

    Scheid, Claudia Miriam; Calcada, Luis Americo [Universidade Federal Rural do Rio de Janeiro (UFRRJ). Departamento de Engenharia Quimica (Brazil)], e-mails: scheid@ufrrj.br, calcada@ufrrj.br; Rocha, Daniele Cristine [Centro de Pesquisas da Petrobras (CENPES). Engenharia Basica de Abastecimento - Gas e Energia (Brazil)], e-mail: drocha@petrobras.com.br; Aranha, Pedro Esteves [Centro de Pesquisas da Petrobras (CENPES). Gerencia de Perfuracao e Completacao de Pocos (Brazil)], e-mail: pearanha@petrobras.com.br; Aragao, Atila Fernando Lima [E and P Construcao de Pocos Maritimos. Gerencia de Tecnologia de Fluidos (Brazil)], e-mail: atila_aragao@petrobras.com.br

    2009-12-15

    An extensive experimental study is detailed to evaluate the friction pressure drop resulting from the flow through pipe and annular sections, accessories such as tool joints, bit jets and stabilizers of four different drilling fluids used in deep water operations. After a data analysis process, it was possible to compile a set of equations to predict relevant hydraulic friction pressure loss calculations, such as: hydraulic diameter for annular flows, friction factors for pipe and annular turbulent flows and discharge coefficients for accessories. (author)

  6. The role of pressurized fluid in subchondral bone cyst growth.

    Science.gov (United States)

    Cox, L G E; Lagemaat, M W; van Donkelaar, C C; van Rietbergen, B; Reilingh, M L; Blankevoort, L; van Dijk, C N; Ito, K

    2011-10-01

    Pressurized fluid has been proposed to play an important role in subchondral bone cyst development. However, the exact mechanism remains speculative. We used an established computational mechanoregulated bone adaptation model to investigate two hypotheses: 1) pressurized fluid causes cyst growth through altered bone tissue loading conditions, 2) pressurized fluid causes cyst growth through osteocyte death. In a 2D finite element model of bone microarchitecture, a marrow cavity was filled with fluid to resemble a cyst. Subsequently, the fluid was pressurized, or osteocyte death was simulated, or both. Rather than increasing the load, which was the prevailing hypothesis, pressurized fluid decreased the load on the surrounding bone, thereby leading to net bone resorption and growth of the cavity. In this scenario an irregularly shaped cavity developed which became rounded and obtained a rim of sclerotic bone after removal of the pressurized fluid. This indicates that cyst development may occur in a step-wise manner. In the simulations of osteocyte death, cavity growth also occurred, and the cavity immediately obtained a rounded shape and a sclerotic rim. Combining both mechanisms increased the growth rate of the cavity. In conclusion, both stress-shielding by pressurized fluid, and osteocyte death may cause cyst growth. In vivo observations of pressurized cyst fluid, dead osteocytes, and different appearances of cysts similar to our simulation results support the idea that both mechanisms can simultaneously play a role in the development and growth of subchondral bone cysts. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Pancreatic tissue fluid pressure during drainage operations for chronic pancreatitis

    DEFF Research Database (Denmark)

    Ebbehøj, N; Borly, L; Madsen, P

    1990-01-01

    Pancreatic tissue fluid pressure was measured in 10 patients undergoing drainage operations for painful chronic pancreatitis. The pressure was measured by the needle technique in the three anatomic regions of the pancreas before and at different stages of the drainage procedure, and the results...... a decrease in pancreatic tissue fluid pressure during drainage operations for pain in chronic pancreatitis. Regional pressure decrease were apparently unrelated to ERCP findings....

  8. Pancreatic tissue fluid pressure during drainage operations for chronic pancreatitis

    DEFF Research Database (Denmark)

    Ebbehøj, N; Borly, L; Madsen, P

    1990-01-01

    Pancreatic tissue fluid pressure was measured in 10 patients undergoing drainage operations for painful chronic pancreatitis. The pressure was measured by the needle technique in the three anatomic regions of the pancreas before and at different stages of the drainage procedure, and the results...... a decrease in pancreatic tissue fluid pressure during drainage operations for pain in chronic pancreatitis. Regional pressure decrease were apparently unrelated to ERCP findings....

  9. Pore pressure migration during hydraulic stimulation due to permeability enhancement by low-pressure subcritical fracture slip

    Science.gov (United States)

    Mukuhira, Yusuke; Moriya, Hirokazu; Ito, Takatoshi; Asanuma, Hiroshi; Häring, Markus

    2017-04-01

    Understanding the details of pressure migration during hydraulic stimulation is important for the design of an energy extraction system and reservoir management, as well as for the mitigation of hazardous-induced seismicity. Based on microseismic and regional stress information, we estimated the pore pressure increase required to generate shear slip on an existing fracture during stimulation. Spatiotemporal analysis of pore pressure migration revealed that lower pore pressure migrates farther and faster and that higher pore pressure migrates more slowly. These phenomena can be explained by the relationship between fracture permeability and stress state criticality. Subcritical fractures experience shear slip following smaller increases of pore pressure and promote migration of pore pressure because of their enhanced permeability. The difference in migration rates between lower and higher pore pressures suggests that the optimum wellhead pressure is the one that can stimulate relatively permeable fractures, selectively. Its selection optimizes economic benefits and minimizes seismic risk.

  10. 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.)

  11. 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

  12. ESTIMATION OF RESIDUAL CONTACT PRESSURE IN HYDRAULICALLY EXPANDED CRA-LINED PIPE

    Institute of Scientific and Technical Information of China (English)

    Wang Xuesheng; Li Peining; Wang Ruzhu

    2004-01-01

    The mechanically bonded CRA-lined pipe is developed to meet the need for corrosion-resistant alloy steel pipe. Residual contact pressure at the interface of lined pipe is important factor that governs the quality of lined pipe. A simplified theoretical method is presented to predict the residual contact pressure created by hydraulic pressure. The calculating equation related hydro-forming pressure to the residual contact pressure between two metal faces is derived. And the validation of the proposed equation is accomplished by comparing its result to those obtained by experimental investigation.

  13. 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.

  14. The role of pressurized fluid in subchondral bone cyst growth

    NARCIS (Netherlands)

    L.G.E. Cox; M.W. Lagemaat; C.C. van Donkelaar; B. van Rietbergen; M.L. Reilingh; L. Blankevoort; C.N. van Dijk; K. Ito

    2011-01-01

    Pressurized fluid has been proposed to play an important role in subchondral bone cyst development. However, the exact mechanism remains speculative. We used an established computational mechanoregulated bone adaptation model to investigate two hypotheses: 1) pressurized fluid causes cyst growth thr

  15. Vorticity and turbulence effects in fluid structure interaction an application to hydraulic structure design

    CERN Document Server

    Brocchini, M

    2006-01-01

    This book contains a collection of 11 research and review papers devoted to the topic of fluid-structure interaction.The subject matter is divided into chapters covering a wide spectrum of recognized areas of research, such as: wall bounded turbulence; quasi 2-D turbulence; canopy turbulence; large eddy simulation; lake hydrodynamics; hydraulic hysteresis; liquid impacts; flow induced vibrations; sloshing flows; transient pipe flow and air entrainment in dropshaft.The purpose of each chapter is to summarize the main results obtained by the individual research unit through a year-long activity

  16. A Study on the Pressure Relief Scope and the Stress Variation of Hydraulic Flushing Borehole

    Directory of Open Access Journals (Sweden)

    C. F.Wei

    2014-01-01

    Full Text Available To study the variation of the pressure relief scope and the stress around hydraulic flushing borehole, the theory of coalrock damage was utilized to distinguish the interaction area of water-jet and coal-rock into the coal-rock crushing area, the water-jet pressure stagnation area, the transition area and the original stress recovery area of coal-rock. Based on the actual occurrence conditions of the coal seam, the pressure variation and relief scope around the hydraulic flushing borehole were analyzed and simulated by RFPA2D-Flow software. The results showed that a relief area with the radius of 5.0 ~ 6.0 m around the borehole formed due to the hydraulic flushing with the pressure relief of 0.038 ~ 6.545 MPa, and the maximum principal stress is 15.85 MPa with a distance of 6.8 m from the inspected hole where stress concentration appeared. After hydraulic flushing test, the diameter (441.8 ~ 1171.6 mm of the hole which can be an expression of coal crushing area size, was calculated based on the examination of the coal amount through the trial process, and it can be drawn that the pressure relief area must be larger than that of the coal-rock crushing area. Meanwhile, the measured pressures relief range(5.96 ~ 6.62 m is basically consistent with the numerical simulation result (5.0 ~ 6.0 m which verified the accuracy of the simulation analysis, according to the distance from the inspection drilling to the hydraulic flushing borehole and the decreased degree of the gas content in the inspection hole by the way of Gas Content.

  17. Methodology for comparison of hydraulic and thermal performance of alternative heat transfer fluids in complex systems

    Energy Technology Data Exchange (ETDEWEB)

    Ghajar, A.J.; Tang, W.C. [Oklahoma State Univ., Stillwater, OK (United States). School of Mechanical and Aerospace Engineering; Beam, J.E. [Power Technology Branch, Wright Patterson AFB, OH (United States). Thermal Technology Section

    1995-01-01

    A general method for the comparison of hydraulic and thermal performance of different liquid coolants in complex systems is offered. As a case study, the performance of polyalphaolefin (PAO) and a silicate ester-based fluid (Coolanol 25R) used as liquid coolants in avionic systems is presented. Thermophysical property expressions for the variation of density, specific heat, thermal conductivity, and kinematic viscosity with temperature for PAO and Coolanol 25R were developed. The range of temperature for this study was from {minus}54 to 135 C. Based on the results, the hydraulic performance of Coolanol 25R is much better than that of PAO at low temperatures (below 0 C) and in the laminar flow regime. In the turbulent region, PAO outperforms Coolanol 25R hydraulically over the entire temperature range. The thermal performance of PAO at temperatures below 61 C and in the laminar flow region is slightly better than that of Coolanol 25R. In the low-temperature turbulent region, Coolanol 25R outperforms PAO thermally. At other temperatures, the performance of the two liquid coolants is reasonably close and fairly independent of the flow regime.

  18. Structure Analysis for a New Type of Vane Hydraulic Damper Using Magneto-rheological Fluid

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jin-qiu; FENG Zhan-zong; WANG Hong-tao

    2008-01-01

    Over recent years the progress in actuator and microelectronics technology has made intelligent suspension systems feasible. Based on conventional vane hydraulic damper, a new vane magneto-rheological fluid (MRF) damper with fail-safe capability is designed. Firstly, the mathematical model of damping moment is deduced based on the parallel-plate model and Bingham model of MR fluids. Secondly, some influence factors of damping adjustable multiple are analyzed to provide some ways for augmenting the damping adjustable multiple under the condition of keeping initial damping moment invariable. Finally, the magnetic circuit is designed, and magnetic field distribution is simulated with the magnetic finite element analysis software-AN,SOFT. The theory and simulation results confirm that the damping adjustable range of vane MRF damper can meet the requirement of heavy vehiele semi-active suspension system.

  19. Pancreatic tissue fluid pressure and pain in chronic pancreatitis

    DEFF Research Database (Denmark)

    Ebbehøj, N

    1992-01-01

    A casual relation between pancreatic pressure and pain has been searched for decades but lack of appropriate methods for pressure measurements has hindered progress. During the 1980's the needle method has been used for direct intraoperative pancreatic tissue fluid pressure measurements and later...... for percutaneous sonographically-guided pressure measurements. Clinical and experimental evaluation of the method showed comparable results at intraoperative and percutaneous measurements and little week-to-week variation. Furthermore, comparable pressures in duct and adjacent pancreatic tissue were found, i.......e. the needle pressure mirrors the intraductal pressure. Comparisons of pain registrations, morphological and functional parameters with pancreatic tissue fluid pressure measurements have revealed a relation between pressure and pain which probably is causal. In patients with pain the high pressures previously...

  20. NUMERICAL SIMULATION AND EXPERIMENTAL RESEARCH ON HYDRAULIC COUNTER-PRESSURE DEEP DRAWING OF CONICAL PART

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Hydraulic counter-pressure deep drawing of truncated conical part is numerically simulated with MARK and the nature of increasing the forming limit in this process is searched.The effects of blank holding force and chamber pressure on forming results are investigated by experiments and,as a result,truncated conical parts with large drawing ratio are successfully formed in single step with this drawing method.

  1. Pressure Responses of a Vertically Hydraulic Fractured Well in a Reservoir with Fractal Structure

    CERN Document Server

    Razminia, Kambiz; Torres, Delfim F M

    2015-01-01

    We obtain an analytical solution for the pressure-transient behavior of a vertically hydraulic fractured well in a heterogeneous reservoir. The heterogeneity of the reservoir is modeled by using the concept of fractal geometry. Such reservoirs are called fractal reservoirs. According to the theory of fractional calculus, a temporal fractional derivative is applied to incorporate the memory properties of the fractal reservoir. The effect of different parameters on the computed wellbore pressure is fully investigated by various synthetic examples.

  2. Controlling a negative loaded hydraulic cylinder using pressure feedback

    DEFF Research Database (Denmark)

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

    2010-01-01

    showing that without extra measures such a system will be unstable in a substantial part of the cylinder stroke. The stability criterion is expressed in hard quantities: Cylinder volumes, cylinder area ratio and overcenter valve pilot area ratio. A pressure feed back scheme that has as target to maintain...

  3. Characteristic analysis of a water hydraulic pilot-operated pressure-reducing valve

    Science.gov (United States)

    Mao, Xuyao; Hu, Junhua; Wu, Chao; Liu, Yiou; Liu, Yinshui

    2017-06-01

    Comprehensive characteristics of a seawater hydraulic pilot-operated pressure-reducing valve with constant pressure output were analyzed. A rated pressure of 15MPa and a rated flowrate of 40L/min were offered in the numerical work. Static and dynamic analyses show good behaviors: The settling time is less than 0.2s, the output pressure variation is about 0.3MPa at the maximum when input pressure or flowrate is flucturing, and the steady external leakage is below 0.025L/min. The pilot spring regulates the output pressure and the main spring has an ability to adjust the output pressure variation faintly. The narrow hole diameter of the adjustable damping plugs is negatively related to the respond time. And appropriately raising the spring chamber volume can evidently reduce outlet pressure impact of the valve when input mutations happen.

  4. Numerical solutions of Williamson fluid with pressure dependent viscosity

    Science.gov (United States)

    Zehra, Iffat; Yousaf, Malik Muhammad; Nadeem, Sohail

    In the present paper, we have examined the flow of Williamson fluid in an inclined channel with pressure dependent viscosity. The governing equations of motion for Williamson fluid model under the effects of pressure dependent viscosity and pressure dependent porosity are modeled and then solved numerically by the shooting method with Runge Kutta Fehlberg for two types of geometries i.e., (i) Poiseuille flow and (ii) Couette flow. Four different cases for pressure dependent viscosity and pressure dependent porosity are assumed and the physical features of pertinent parameters are discussed through graphs.

  5. Numerical solutions of Williamson fluid with pressure dependent viscosity

    Directory of Open Access Journals (Sweden)

    Iffat Zehra

    2015-01-01

    Full Text Available In the present paper, we have examined the flow of Williamson fluid in an inclined channel with pressure dependent viscosity. The governing equations of motion for Williamson fluid model under the effects of pressure dependent viscosity and pressure dependent porosity are modeled and then solved numerically by the shooting method with Runge Kutta Fehlberg for two types of geometries i.e., (i Poiseuille flow and (ii Couette flow. Four different cases for pressure dependent viscosity and pressure dependent porosity are assumed and the physical features of pertinent parameters are discussed through graphs.

  6. Abrasion properties of homogenous and blended fill materials during pressure hydraulic transport

    Energy Technology Data Exchange (ETDEWEB)

    Turchaninov, S.P.

    1978-03-01

    A description is given of tests conducted to determine the abrasive properties of small and large-grain free-flowing fill materials during hydraulic transport of the materials under pressure. Data are given on the size, density, abrasiveness of various sized varieties of rock, sand, and blends comprising homogenous materials, simple and complex mixtures, and on the physical characteristics of various fill materials in relation to the trafficability and parameters of pipelines. Technical specifications are given for fill steel pipes. The study indicates that the durability of hydraulic fill pipelines largely depends on the abrasiveness of the fill materials. 3 references, 2 figures, 2 tables.

  7. 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

    2017-05-01

    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.

  8. Effect of pressure on the physical properties of magnetorheological fluids

    Directory of Open Access Journals (Sweden)

    A. Spaggiari

    2013-01-01

    Full Text Available To date, several applications of magnetorheological (MR fluids are present in the industrial world, nonetheless system requirements often needs better material properties. In technical literature a previous work shows that MR fluids exhibit a pressure dependency called squeeze strengthen effect. Since a lot of MR fluid based devices are rotary devices, this paper investigates the behaviour of MR fluids under pressure when a rotation is applied to shear the fluid. The system is designed in order to apply both the magnetic field and the pressure and follows a Design of Experiment approach. The experimental apparatus comprises a cylinder in which a piston is used both to apply the pressure and to shear the fluid. The magnetic circuit is designed to provide a nearly constant induction field in the MR fluid. The experimental apparatus measures the torque as a function of the variables considered and the yield shear stress is computed. The analysis of the results shows that there is a positive interaction between magnetic field and pressure, which enhances the MR fluid performances more than twice.

  9. Multibody Dynamics of a Fluid Power Radial Piston Motor Including Transient Hydrodynamic Pressure Models of Lubricating Gaps

    DEFF Research Database (Denmark)

    Johansen, Per; Rømer, Daniel; Andersen, Torben Ole

    2014-01-01

    is a multibody dynamics model of a radial piston fluid power motor, which connects the rigid bodies through models of the transient hydrodynamic lubrication pressure in the joint clearance. A finite volume approach is used to model the pressure dynamics of the fluid film lubrication. The model structure......The increasing interest in hydraulic transmissions in wind and wave energy applications has created an incentive for the development of high efficiency fluid power machinery. Modeling and analysis of fluid power machinery loss mechanisms are necessary in order to accommodate this demand. At present...... fully coupled thermo-elastic models has been used to simulate and study loss mechanisms in various tribological interfaces. Consequently, a reasonable focus of further development is to couple the interface models and the rigid body mechanics of fluid power machinery. The focus of the current paper...

  10. The Thermodynamical Instability Induced by Pressure Ionization in Fluid Helium

    CERN Document Server

    Li, Qiong; Zhang, Gong-Mu; Zhao, Yan-Hong; Lu, Guo; Tian, Ming-Feng; Song, Hai-Feng

    2016-01-01

    A systematic study of pressure ionization is carried out in the chemical picture by the example of fluid helium. By comparing the variants of the chemical model, it is demonstrated that the behavior of pressure ionization depends on the construction of the free energy function. In the chemical model with the Coulomb free energy described by the Pad\\'e interpolation formula, thermodynamical instability induced by pressure ionization is found to be manifested by a discontinuous drop or a continuous fall and rise along the pressure-density curve as well as the pressure-temperature curve, which is very much like the first order liquid-liquid phase transition of fluid hydrogen from the first principles simulations. In contrast, in the variant chemical model with the Coulomb free energy term empirically weakened, no thermodynamical instability is induced when pressure ionization occurs, and the resulting equation of state achieves good agreement with the first principles simulations of fluid helium.

  11. THEORETICAL ANALYSIS ON HYDRAULIC TRANSIENT RESULTED BY SUDDEN INCREASE OF INLET PRESSURE FOR LAMINAR PIPELINE FLOW

    Institute of Scientific and Technical Information of China (English)

    邓松圣; 周绍骑; 廖振方; 邱正阳; 曾顺鹏

    2004-01-01

    Hydraulic transient,which is resulted from sudden increase of inlet pressure for laminar pipeline flow,is studied.The partial differential equation,initial and boundary conditions for transient pressure were constructed,and the theoretical solution was obtained by variable-separation method.The partial differential equation,initial and boundary conditions for flow rate were obtained in accordance with the constraint correlation between flow rate and pressure while the transient flow rate distribution was also solved by variable-separation method.The theoretical solution conforms to numerical solution obtained by method of characteristics(MOC)very well.

  12. Experimental and modeling hydraulic studies of foam drilling fluid flowing through vertical smooth pipes

    Directory of Open Access Journals (Sweden)

    Amit Saxena

    2017-06-01

    Full Text Available Foam has emerged as an efficient drilling fluid for the drilling of low pressure, fractured and matured reservoirs because of its the ability to reduce formation damage, fluid loss, differential sticking etc. However the compressible nature along with its complicated rheology has made its implementation a multifaceted task. Knowledge of the hydrodynamic behavior of drilling fluid within the borehole is the key behind successful implementation of drilling job. However, little effort has been made to develop the hydrodynamic models for the foam flowing with cuttings through pipes of variable diameter. In the present study, hydrodynamics of the foam fluid was investigated through the vertical smooth pipes of different pipe diameters, with variable foam properties in a flow loop system. Effect of cutting loading on pressure drop was also studied. Thus, the present investigation estimates the differential pressure loss across the pipe. The flow loop permits foam flow through 25.4 mm, 38.1 mm and 50.8 mm diameter pipes. The smaller diameter pipes are used to replicate the annular spaces between the drill string and wellbore. The developed model determines the pressure loss along the pipe and the results are compared with a number of existing models. The developed model is able to predict the experimental results more accurately.

  13. Theory and application of rock burst prevention using deep hole high pressure hydraulic fracturing

    Institute of Scientific and Technical Information of China (English)

    Shan-Kun ZHAO; Jun LIU; Xiang-Zhi WEI; Chuan-Hong DING; Yu-Lei LV; Gang-Feng LI

    2013-01-01

    In order to analyze the mechanism of deep hole high pressure hydraulic fracturing,nonlinear dynamic theory,damage mechanics,elastic-plastic mechanics are used,and the law of crack propagation and stress transfer under two deep hole hydraulic fracturing in tectonic stress areas is studied using seepage-stress coupling models with RFPA simulation software.In addition,the effects of rock burst control are tested using multiple methods,either in the stress field or in the energy field.The research findings show that with two deep holes hydraulic fracturing in tectonic stress areas,the direction of the main crack propagation under shear-tensile stress is parallel to the greatest principal stress direction.High-pressure hydraulic fracturing water seepage can result in the destruction of the coal structure,while also weakening the physical and mechanical properties of coal and rock.Therefore the impact of high stress concentration in hazardous areas will level off,which has an effect on rock burst prevention and control in the region.

  14. Osmotic pressure of the cutaneous surface fluid of Rana esculenta

    DEFF Research Database (Denmark)

    Hviid Larsen, Erik; Ramløv, Hans

    2012-01-01

    The osmotic pressure of the cutaneous surface fluid (CSF) in vivo was measured for investigating whether evaporative water loss (EWL) derives from water diffusing through the skin or fluid secreted by exocrine subepidermal mucous glands. EWL was stimulated by subjecting R. esculenta to 30–34 °C...

  15. 基于FluidSIM-Hydraulic的注塑机液压回路控制分析%Control Analysis for Hydraulic Loop of Plastic Injection Molding Machine Based on FluidSIM-Hydraulic

    Institute of Scientific and Technical Information of China (English)

    叶金玲; 周钦河; 黄诚

    2015-01-01

    Hydraulic control system of plastic injection molding machine was designed using FluidSIM⁃Hydraulic software. The structure and working principle of the plastic injection molding machine were introduced, its hydraulic loop and electric loop were de⁃signed and optimized. The plastic injection molding machine has gained good affection in actual production.%基于FluidSIM⁃Hydraulic软件对注塑机液压回路控制系统进行分析。介绍了注塑机的结构原理,并优化设计了液压回路及电气控制系统,通过二者有效的结合成功地将模拟仿真后的模型应用到了实际生产中,取得了良好的效果。

  16. Constant-Differential-Pressure Two-Fluid Accumulator

    Science.gov (United States)

    Piecuch, Benjamin; Dalton, Luke T.

    2010-01-01

    A two-fluid accumulator has been designed, built, and demonstrated to provide an acceptably close approximation to constant differential static pressure between two fluids over the full ranges of (1) accumulator stroke, (2) rates of flow of the fluids, and (3) common static pressure applied to the fluids. Prior differential- pressure two-fluid accumulators are generally not capable of maintaining acceptably close approximations to constant differential pressures. The inadequacies of a typical prior differential-pressure two-fluid accumulator can be summarized as follows: The static differential pressure is governed by the intrinsic spring rate (essentially, the stiffness) of an accumulator tank. The spring rate can be tailored through selection of the tank-wall thickness, selection of the number and/or shape of accumulator convolutions, and/or selection of accumulator material(s). Reliance on the intrinsic spring rate of the tank results in three severe limitations: (1) The spring rate and the expulsion efficiency tend to be inversely proportional to each other: that is to say, as the stiffness (and thus the differential pressure) is increased, the range of motion of the accumulator is reduced. (2) As the applied common static pressure increases, the differential pressure tends to decrease. An additional disadvantage, which may or may not be considered limiting, depending on the specific application, is that an increase in stiffness entails an increase in weight. (3) The additional weight required by a low expulsion efficiency accumulator eliminates the advantage given to such gas storage systems. The high expulsion efficiency provided by this two-fluid accumulator allows for a lightweight, tightly packaged system, which can be used in conjunction with a fuel cell-based system.

  17. Genome-Centric Analysis of Microbial Populations Enriched by Hydraulic Fracture Fluid Additives in a Coal Bed Methane Production Well.

    Science.gov (United States)

    Robbins, Steven J; Evans, Paul N; Parks, Donovan H; Golding, Suzanne D; Tyson, Gene W

    2016-01-01

    Coal bed methane (CBM) is generated primarily through the microbial degradation of coal. Despite a limited understanding of the microorganisms responsible for this process, there is significant interest in developing methods to stimulate additional methane production from CBM wells. Physical techniques including hydraulic fracture stimulation are commonly applied to CBM wells, however the effects of specific additives contained in hydraulic fracture fluids on native CBM microbial communities are poorly understood. Here, metagenomic sequencing was applied to the formation waters of a hydraulically fractured and several non-fractured CBM production wells to determine the effect of this stimulation technique on the in-situ microbial community. The hydraulically fractured well was dominated by two microbial populations belonging to the class Phycisphaerae (within phylum Planctomycetes) and candidate phylum Aminicenantes. Populations from these phyla were absent or present at extremely low abundance in non-fractured CBM wells. Detailed metabolic reconstruction of near-complete genomes from these populations showed that their high relative abundance in the hydraulically fractured CBM well could be explained by the introduction of additional carbon sources, electron acceptors, and biocides contained in the hydraulic fracture fluid.

  18. Development of Design Technology on Thermal-Hydraulic Performance in Tight-Lattice Rod Bundles: III - Numerical Evaluation of Fluid Mixing Phenomena using Advanced Interface-Tracking Method -

    Science.gov (United States)

    Yoshida, Hiroyuki; Nagayoshi, Takuji; Takase, Kazuyuki; Akimoto, Hajime

    Thermal-hydraulic design of the current boiling water reactor (BWR) is performed by correlations with empirical results of actual-size tests. However, for the Innovative Water Reactor for Flexible Fuel Cycle (FLWR) core, an actual size test of an embodiment of its design is required to confirm or modify such correlations. Development of a method that enables the thermal-hydraulic design of nuclear reactors without these actual size tests is desired, because these tests take a long time and entail great cost. For this reason we developed an advanced thermal-hydraulic design method for FLWRs using innovative two-phase flow simulation technology. In this study, detailed Two-Phase Flow simulation code using advanced Interface Tracking method: TPFIT is developed to calculate the detailed information of the two-phase flow. We tried to verify the TPFIT code by comparing it with the 2-channel air-water and steam-water mixing experimental results. The predicted result agrees well the observed results and bubble dynamics through the gap and cross flow behavior could be effectively predicted by the TPFIT code, and pressure difference between fluid channels is responsible for the fluid mixing.

  19. Tribological properties of hydraulic fluids modified by peat-based additives

    Science.gov (United States)

    Ionov, V. V.; Larionov, S. A.; Sarkisov, Ju S.; Kopanica, N. O.; Gorchkova, A. V.; Gorlenko, N. P.; Tzevtkov, N. A.; Ikonnikova, K. V.

    2017-02-01

    The paper presents physicochemical investigations of the structure and properties of a nano-modifier synthesized from peat, the local raw material subjected to pyrolysis in air-free conditions. This nano-modifying additive is a combination of various forms of nanocarbon and polar and non-polar adsorbing materials such as silica (SiO2), calcium carbonate (CaCO3) and carbon (C). Different nanocarbon forms (nanotubes, fullerenes, nanodiamonds, nanofiber, nanodispersed carbon) used in different proportions with micro and macro peat components give multifunctional properties to the synthesized nano-modifier and the ability to positively change tribological properties of hydraulic fluids and oil lubricants. Test results of type TMT-600 show that its different percentage is required to modify tribological properties of the steel tribocouple under different loading conditions. At 0.5 wt.% content of this nano-modifier, stabilization of the friction ratio and an increase of seizure load are observed.

  20. Hydraulic Resistance and Liberation of Air in Aviation Kerosene Flow Through Diaphragms at Low Pressure

    Science.gov (United States)

    Kitanin, É. L.; Kitanina, E. É.; Zherebtsov, V. A.; Peganova, M. M.; Stepanov, S. G.; Bondarenko, D. A.; Morisson, D.

    2016-09-01

    This paper presents the results of experimental investigations of the liberation of air in gravity flow of aviation fuel through a pipeline with diaphragms. Experiments were carried out in the pressure range 0.2-1.0 bar and temperature range -20 to +20°C. The TC-1 kerosene was preliminarily saturated with air at atmospheric pressure. The liberation of air after the diaphragms with three ratios of the flow area to the cross-sectional area of the pipeline has been investigated. The results of investigations of the two-phase flow in several experimental pipelines containing one or two diaphragms and other local hydraulic resistances have been generalized. The obtained approximation equations permit calculating the hydraulic resistance of the diaphragm in the two-phase flow and the mass gas content of air after the diaphragm in pipelines of complex geometry.

  1. Thermal Hydraulic Analysis of a Passive Residual Heat Removal System for an Integral Pressurized Water Reactor

    OpenAIRE

    2009-01-01

    A theoretical investigation on the thermal hydraulic characteristics of a new type of passive residual heat removal system (PRHRS), which is connected to the reactor coolant system via the secondary side of the steam generator, for an integral pressurized water reactor is presented in this paper. Three-interknited natural circulation loops are adopted by this PRHRS to remove the residual heat of the reactor core after a reactor trip. Based on the one-dimensional model and a simulation code (S...

  2. Development and implementation of a fluid flow code to evaluate block hydraulic behaviors of the fractured rock masses

    Science.gov (United States)

    Um, Jeong-Gi; Han, Jisu; Lee, Dahye; Cho, Taechin

    2017-04-01

    A computer program code was developed to estimate the hydraulic head distribution through the 2-D DFN(discrete fracture network) blocks considering hydraulic aperture of the individual fractures, and to determine flow quantity, directional block hydraulic conductivity and principal hydraulic conductivity tensor according to fracture geometry such as orientation, frequency and size of the fracture network systems. The generated stochastic DFN system is assumed to have a network structure in which the equivalent flow pipe composed linear fractures is complexly connected. DFN systems often include individual or group of sub-network that are isolated from a network that can act as fluid flow passages from one flow boundary to another, and the fluid flow is completely blocked due to lack of connectivity. Fractures that are completely or partially isolated in the DFN system do not contribute to the overall fluid flow through the DFN system and add to the burden of numerical computation. This sometimes leads to numerical instability and failure to provide a solution. In this study, geometric and mathematical routines were designed and implemented to classify and eliminate such sub-networks. The developed program code can calculate the total head at each node connected to the flow path with various aperture as well as hydraulic conductivity of the individual flow pipe using the SOR method. Numerical experiments have been carried out to explore the applicability of the developed program code. A total of 108 stochastic 2-D DFN blocks of 20 m×20 m with various hydraulic aperture were prepared using two joint sets with fixed input parameters of fracture orientation, frequency and size distribution. The hydraulic anisotropy and the chance for equivalent continuum behavior of the DFN system were found to depend on the variability of fracture aperture.

  3. NUMERICAL SIMULATION AND ANALYSIS OF PRESSURE PULSATION IN FRANCIS HYDRAULIC TURBINE WITH AIR ADMISSION

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this article, the three-dimensional unsteady multiphase flow is simulated in the whole passage of Francis hydraulic turbine. The pressure pulsation is predicted and compared with experimental data at positions in the draft tube, in front of runner, guide vanes and at the inlet of the spiral case. The relationship between pressure pulsation in the whole passage and air admission is analyzed. The computational results show: air admission from spindle hole decreases the pressure difference in the horizontal section of draft tube, which in turn decreases the amplitude of low-frequency pressure pulsation in the draft tube; the rotor-stator interaction between the air inlet and the runner increases the blade-frequency pressure pulsation in front of the runner.

  4. Critical Pressures of the Thrust Bearing Using a Magnetic Fluid

    OpenAIRE

    長屋, 幸助; 武田, 定彦; 佐藤, 淳; 井開, 重男; 関口, 肇; 斉藤, 登

    1990-01-01

    This paper proposes a thrust bearing lubricated by a magnetic fluid under a magnetic field. The critical pressures of the bearing versus the magnitude of the magnetic flux densities have been investigated experimentally. It is clarified that the critical pressures of the proposed bearing are larger than those of the normal lubricant bearing under high speeds.

  5. pressure analysis and fluid contact prediction for alpha reservoir

    African Journals Online (AJOL)

    HOD

    As pressure data was not acquired in the water leg of the reservoir, pressure gradient analysis was done with the field-wide hydrostatic profile for contact and fluid prediction. Also, an ... within this depth range (Figure 4). The presence of an.

  6. Estimating hydraulic conductivity of fractured rocks from high‐pressure packer tests with an Izbash's law‐based empirical model

    National Research Council Canada - National Science Library

    Chen, Yi‐Feng; Hu, Shao‐Hua; Hu, Ran; Zhou, Chuang‐Bing

    2015-01-01

    ...‐pressure groundwater flow conditions. The interpretation of the HPPT data, however, remains difficult due to the transition of flow conditions in the conducting structures and the hydraulic fracturing...

  7. High-pressure fluid phase equilibria phenomenology and computation

    CERN Document Server

    Deiters, Ulrich K

    2012-01-01

    The book begins with an overview of the phase diagrams of fluid mixtures (fluid = liquid, gas, or supercritical state), which can show an astonishing variety when elevated pressures are taken into account; phenomena like retrograde condensation (single and double) and azeotropy (normal and double) are discussed. It then gives an introduction into the relevant thermodynamic equations for fluid mixtures, including some that are rarely found in modern textbooks, and shows how they can they be used to compute phase diagrams and related properties. This chapter gives a consistent and axiomatic approach to fluid thermodynamics; it avoids using activity coefficients. Further chapters are dedicated to solid-fluid phase equilibria and global phase diagrams (systematic search for phase diagram classes). The appendix contains numerical algorithms needed for the computations. The book thus enables the reader to create or improve computer programs for the calculation of fluid phase diagrams. introduces phase diagram class...

  8. Geochemical simulation of fluid rock interactions to predict flowback water compostions during hydraulic fracturing

    Science.gov (United States)

    Kühn, Michael; Vieth-Hillebrand, Andrea; Wilke, Franziska D. H.

    2017-04-01

    Black shales are a heterogeneous mixture of minerals, organic matter and formation water and little is actually known about the fluid-rock interactions during hydraulic fracturing and their effects on composition of flowback and produced water. Geochemical simulations have been performed based on the analyses of "real" flowback water samples and artificial stimulation fluids from lab experiments with the aim to set up a chemical process model for shale gas reservoirs. Prediction of flowback water compositions for potential or already chosen sites requires validated and parameterized geochemical models. For the software "Geochemist's Workbench" (GWB) data bases are adapted and amended based on a literature review. Evaluation of the system has been performed in comparison with the results from laboratory experiments. Parameterization was done in regard to field data provided. Finally, reaction path models are applied for quantitative information about the mobility of compounds in specific settings. Our work leads to quantitative estimates of reservoir compounds in the flowback based on calibrations by laboratory experiments. Such information is crucial for the assessment of environmental impacts as well as to estimate human- and ecotoxicological effects of the flowback waters from a variety of natural gas shales. With a comprehensive knowledge about potential composition and mobility of flowback water, selection of water treatment techniques will become easier.

  9. Computational fluid dynamics simulation and geometric design of hydraulic turbine draft tube

    Directory of Open Access Journals (Sweden)

    JB Sosa

    2015-10-01

    Full Text Available Any hydraulic reaction turbine is installed with a draft tube that impacts widely the entire turbine performance, on which its functions are as follows: drive the flux in appropriate manner after it releases its energy to the runner; recover the suction head by a suction effect; and improve the dynamic energy in the runner outlet. All these functions are strongly linked to the geometric definition of the draft tube. This article proposes a geometric parametrization and analysis of a Francis turbine draft tube. Based on the parametric definition, geometric changes in the draft tube are proposed and the turbine performance is modeled by computational fluid dynamics; the boundary conditions are set by measurements performed in a hydroelectric power plant. This modeling allows us to see the influence of the draft tube shape on the entire turbine performance. The numerical analysis is based on the steady-state solution of the turbine component flows for different guide vanes opening and multiple modified draft tubes. The computational fluid dynamics predictions are validated using hydroelectric plant measurements. The prediction of the turbine performance is successful and it is linked to the draft tube geometric features; therefore, it is possible to obtain a draft tube parameter value that results in a desired turbine performance.

  10. APHRON-BASED DRILLING FLUIDS: SOLUTION FOR LOW PRESSURE RESERVOIRS

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    2009-12-01

    Full Text Available Drilling wells throughout depleted or low pressure reservoirs requires low density drilling fluids, often with density less than water. Methods to reduce the density of drilling fluids have included mixing-in air or nitrogen. However, problems with these approaches include instability of gas bubbles (bubbles collapse or expand and increased costs. Recently, the use of micro bubbles named aphrons in drilling, completion and workover fluids has proven success in solving many problems related to low pressure reservoirs such as fluid loss control, formation damage, stabilization of multipressure sequences with one fluid and possible differential sticking. Aphrons represent bubble with uniquely structure stabilized with surfactant. Against conventional micro bubbles, aphrons are more stable in downhole conditions and they are generated using standard mixing equipment. Owing to their properties and overpressure in wellbore aphrons penetrate into low pressure layers and set up inner bridging. Depleted wells which are very expensive to drill underbalanced or with other remediation techniques can now be drilled overbalanced. This paper presents description of aphron structure and stability, aphron bridging mechanism, aphron-based fluid composition and properties, and field experiences in applying aphron-based fluids.

  11. 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.

  12. Negative pressure in shear thickening band of a dilatant fluid

    CERN Document Server

    Nagahiro, Shin-ichiro

    2015-01-01

    We perform experiments and numerical simulations to investigate spatial distribution of pressure in a sheared dilatant fluid of the Taylor-Couette flow under a constant external shear stress. In a certain range of shear stress, the flow undergoes the shear thickening oscillation around 20 Hz. The pressure measurement during the oscillation at the wall of the outer cylinder indicates that a localized negative pressure region rotates around the axis with the flow. The maximum negative pressure is close to the Laplace pressure of the grain radius and nearly independent of the applied shear stress. Simulations of a phenomenological model reveal that the thickened region is dominated by a negative pressure band, which extends along the tensile direction in the flow. Such shear thickening with negative pressure contradicts a naive picture of jamming mechanism, where thickening is expected in the compressing direction with the positive pressure.

  13. Pressure Control of Electro-Hydraulic Servovalve and Transmission Line Effect

    Directory of Open Access Journals (Sweden)

    Ahmed Fouad Mahdi

    2013-06-01

    Full Text Available The effected of the long transmission line (TL between the actuator and the hydraulic control valve sometimes essentials. The study is concerned with modeling the TL which carries the oil from the electro-hydraulic servovalve to the actuator. The pressure value inside the TL has been controlled by the electro-hydraulic servovalve as a voltage supplied to the servovalve amplifier. The flow rate through the TL has been simulated by using the lumped π element electrical analogy method for laminar flow. The control voltage supplied to servovalve can be achieved by the direct using of the voltage function generator or indirect C++ program connected to the DAP-view program built in the DAP-card data acquisition connected to PC, to control the value of pressure in a selected point in the TL. It has been found that the relation between the voltage value and the output flow rate from the servovalve in most of the path is a linear relation. The MATLAB m-File program is used to create a representation state of the mathematical model to find a good simulation for the experimental open loop control test.

  14. 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

    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...... 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...

  15. Differences in hydraulic pressure producing efficiency of front suspension units for motorcycles due to structural difference

    Energy Technology Data Exchange (ETDEWEB)

    Kajino, Tsutomu; Namazue, Eitaro; Ueno, Yutaka

    1995-12-31

    The front suspension unit for motorcycles is one of the functional parts for which continuous engineering improvement is required for advanced driveability. Especially, the ones for off-road motocross racing are frequently required to have their energy absorbing properties, ability to maintain tire-to-ground contact, driving comfort, etc. to be improved to meet the challenges of the racing courses which include many jumps, to exceed the performance of competitors, and to match the ever-improving performance of the engines and frames. To cope with the situation, the operability, rigidity and hydraulic pressure producing mechanism needs to be upgraded. As part of an improvement program, the authors have developed a air-oil separated front suspension which the authors have called the ``twin chamber`` suspension. In this study, the authors compared the hydraulic pressure producing efficiency of the air-oil separated suspension with that of the conventional single chamber construction. The results of the comparison showed that the twin chamber suspension is less affected by the pressure hysteresis by 8% or more at the piston area and 50% or more at the partition area than the conventional suspension. In addition, for the twin chamber suspension, the rise of pressure becomes smoother to give a quicker response as the velocity increases.

  16. Design of hydraulic output Stirling engine

    Science.gov (United States)

    Toscano, W. M.; Harvey, A. C.; Lee, K.

    1983-01-01

    A hydraulic output system for the RE-1000 free piston stirling engine (FPSE) was designed. The hydraulic output system can be readily integrated with the existing hot section of RE-1000 FPSE. The system has two simply supported diaphragms which separate the engine gas from the hydraulic fluid, a dynamic balance mechanism, and a novel, null center band hydraulic pump. The diaphragms are designed to endure more than 10 billion cycles, and to withstand the differential pressure load as high as 14 MPa. The projected thermodynamic performance of the hydraulic output version of RE-1000 FPSE is 1.87 kW at 29/7 percent brake efficiency.

  17. 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.

  18. Integrated Experimental and Computational Study of Hydraulic Fracturing and the Use of Alternative Fracking Fluids

    Science.gov (United States)

    Viswanathan, H.; Carey, J. W.; Karra, S.; Porter, M. L.; Rougier, E.; Zhang, D.; Makedonska, N.; Middleton, R. S.; Currier, R.; Gupta, R.; Lei, Z.; Kang, Q.; O'Malley, D.; Hyman, J.

    2014-12-01

    Shale gas is an unconventional fossil energy resource that is already having a profound impact on US energy independence and is projected to last for at least 100 years. Production of methane and other hydrocarbons from low permeability shale involves hydrofracturing of rock, establishing fracture connectivity, and multiphase fluid-flow and reaction processes all of which are poorly understood. The result is inefficient extraction with many environmental concerns. A science-based capability is required to quantify the governing mesoscale fluid-solid interactions, including microstructural control of fracture patterns and the interaction of engineered fluids with hydrocarbon flow. These interactions depend on coupled thermo-hydro-mechanical-chemical (THMC) processes over scales from microns to tens of meters. Determining the key mechanisms in subsurface THMC systems has been impeded due to the lack of sophisticated experimental methods to measure fracture aperture and connectivity, multiphase permeability, and chemical exchange capacities at the high temperature, pressure, and stresses present in the subsurface. This project uses innovative high-pressure microfluidic and triaxial core flood experiments on shale to explore fracture-permeability relations and the extraction of hydrocarbon. These data are integrated with simulations including lattice Boltzmann modeling of pore-scale processes, finite-element/discrete element models of fracture development in the near-well environment, discrete-fracture modeling of the reservoir, and system-scale models to assess the economics of alternative fracturing fluids. The ultimate goal is to make the necessary measurements to develop models that can be used to determine the reservoir operating conditions necessary to gain a degree of control over fracture generation, fluid flow, and interfacial processes over a range of subsurface conditions.

  19. The design of hydraulic pressure regulators that are stable without the use of sensing line restrictors or frictional dampers

    Science.gov (United States)

    Gold, H.

    1977-01-01

    A direct-acting hydraulic pressure regulator design which incorporates stability margin, response and droop margin is developed. The pressure regulator system does not involve a nonlinear sensing line restrictor (which may degrade transient response) or linear damping (which is sensitive to clearance and viscosity). The direct-acting hydraulic pressure regulator makes use of the technique of lead network stabilization (i.e., the tuned stabilizer concept). An analytically derived circuit pressure regulator is tested to study the stability limit under a parallel capacitive plus resistive load and the stabilizing effect of the tuned stabilizer.

  20. Fluid-filled blood pressure measurement systems.

    Science.gov (United States)

    Li, J K; van Brummelen, A G; Noordergraaf, A

    1976-05-01

    The performance of catheter-manometer systems for the measurement of pulsatile pressure has been evaluated by both experimental techniques and theoretical considerations. The former approach has shown, on occasion, multiple maxima in the amplitude response. The latter has been approached in a variety of ways, ranging from extreme lumping to application of transmission line theory while employing different configurations in the system's representation. Multiple maxima have also been seen, The present paper identifies the sources of the differences found and compares the relative merits of various theoretical approaches. It introduces the compliance of the system as a figure of merit and provides a simple first-order approximation formula for evaluation of the quality of a system. Damping and impedance matching to improve the system's frequency response were studied. It was found that they were not needed in a very stiff or a very compliant system, nor should one worry about the representation of such a system.

  1. Percutaneous biliary stones removal using balloon sphincteroplasty and hydraulic pressure as primary therapeutic method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Soo; You, Jin Jong [Gyeongsang National University Hospital, Chinju (Korea, Republic of)

    2005-07-15

    We wanted to report on the efficacy and safety of the percutaneous biliary stone removal technique using hydraulic pressure after balloon sphincteroplasty through the PTBD tract for patients with bile duct stones. The subjects of this study were 85 patients (46 men and 39 women) with bile duct stones who came to hospital over a period of the previous 4 years. All subjects had undergone attempts for with the biliary tree through PTBD. First, an 8-9F sheath was inserted into the biliary tree through the PTBD route by using a balloon catheter prior to sphincteroplasty, and 50cc of hydraulic pressure with contrast-mixed saline solution was then injected via the sheath. Follow-up cholangiogram was performed 1-3 days later to evaluate the results of stone removal. For residual stones, we attempted second, third, and fourth trials to completely remove the stones. The size and number of stones were analyzed. The results were analyzed, together with the complications, after classifying the cases as 'success', 'partial removal' or 'failure' according to the number of remaining stones. Out of 85 patients, 71 (83%) cases had successful results, and 43 (51%) cases resulted in success with the first attempt. The second, third and fourth trials were conducted on 16, 10 and 2 cases, respectively. Out of 14 failure cases, 10 patients had too many intrahepatic duct stones. The complications were abdominal pain (n=21), fever (n=9), and pancreatitis (n=2), and portal vein thrombosis, biloma and sepsis were also found in 1 case each. We report that this percutaneus biliary stone removal technique using hydraulic pressure after balloon sphincteroplasty through the PTBD is safe and effective, and particularly, it achieves good results as the primary therapy for treating only choledocholiths.

  2. A novel high-temperature and high-pressure hydraulic pump based on mononeuron control

    Institute of Scientific and Technical Information of China (English)

    Linhui ZHAO; Xin FANG

    2009-01-01

    Based on structures and characteristics of traditional hydraulic pumps, this paper proposes a novel high-temperature and high-pressure hydraulic pump (HHHP) that can work under 150℃ and 28MPa to overcome problems of traditional high-temperature plun-ger pumps. The HHHP is designed with the structure of mechanical division and double cylinder parallel. The control signals of two cylinders are two separate triangle waveforms with 90℃ phase difference. Because the output waveforms of two cylinders have the same characteristics as the control signals, the HHHP can obtain a stable output after two separate waveforms are superposed. A mono-neuron self-adaptive PID control algorithm is also improved by modifying parameters K and η. Two improved controllers are used to control the two cylinders,respectively, making two displacements of plungers match each other. Therefore, reduced fluctuations and stable pressure output is obtained. Besides simulation, tests on the built prototype test system are carried out to verify the performance of HHHP. Results show that the improved control approach can limit fluctuations to a lower level and the HHHP system attains good outputs under different signal periods and different pressures.

  3. Thermal Hydraulic Computational Fluid Dynamics Simulations and Experimental Investigation of Deformed Fuel Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Mays, Brian [AREVA Federal Services, Lynchburg, VA (United States); Jackson, R. Brian [TerraPower, Bellevue, WA (United States)

    2017-03-08

    The project, Toward a Longer Life Core: Thermal Hydraulic CFD Simulations and Experimental Investigation of Deformed Fuel Assemblies, DOE Project code DE-NE0008321, was a verification and validation project for flow and heat transfer through wire wrapped simulated liquid metal fuel assemblies that included both experiments and computational fluid dynamics simulations of those experiments. This project was a two year collaboration between AREVA, TerraPower, Argonne National Laboratory and Texas A&M University. Experiments were performed by AREVA and Texas A&M University. Numerical simulations of these experiments were performed by TerraPower and Argonne National Lab. Project management was performed by AREVA Federal Services. The first of a kind project resulted in the production of both local point temperature measurements and local flow mixing experiment data paired with numerical simulation benchmarking of the experiments. The project experiments included the largest wire-wrapped pin assembly Mass Index of Refraction (MIR) experiment in the world, the first known wire-wrapped assembly experiment with deformed duct geometries and the largest numerical simulations ever produced for wire-wrapped bundles.

  4. Exposure of aircraft maintenance technicians to organophosphates from hydraulic fluids and turbine oils: a pilot study.

    Science.gov (United States)

    Schindler, Birgit Karin; Koslitz, Stephan; Weiss, Tobias; Broding, Horst Christoph; Brüning, Thomas; Bünger, Jürgen

    2014-01-01

    Hydraulic fluids and turbine oils contain organophosphates like tricresyl phosphate isomers, triphenyl phosphate and tributyl phosphate from very small up to high percentages. The aim of this pilot study was to determine if aircraft maintenance technicians are exposed to relevant amounts of organophosphates. Dialkyl and diaryl phosphate metabolites of seven organophosphates were quantified in pre- and post-shift spot urine samples of technicians (N=5) by GC-MS/MS after solid phase extraction and derivatization. Pre- and post shift values of tributyl phosphate metabolites (dibutyl phosphate (DBP): median pre-shift: 12.5 μg/L, post-shift: 23.5 μg/L) and triphenyl phosphate metabolites (diphenyl phosphate (DPP): median pre-shift: 2.9 μg/L, post-shift: 3.5 μg/L) were statistically higher than in a control group from the general population (median DBP: aircraft maintenance technicians were occupationally exposed to tributyl and triphenyl phosphate but not to tricresyl phosphate, tri-(2-chloroethyl)- and tri-(2-chloropropyl)-phosphate. Further studies are necessary to collect information on sources, routes of uptake and varying exposures during different work tasks, evaluate possible health effects and to set up appropriate protective measures. Copyright © 2013 Elsevier GmbH. All rights reserved.

  5. Electrochemical determination of water in environmental hydraulic fluids using the karl Fischer reaction.

    Science.gov (United States)

    Cedergren, A; Lundström, M

    1997-10-01

    Different procedures based on the Karl Fischer reaction were investigated with respect to their applicability for water determinations in environmental hydraulic fluids:  (i) continuous coulometry using a recently described diaphragm-free cell; (ii) on-line stripping of water at elevated temperature using either continuous coulometry or direct potentiometry for detection of the liberated water. Except for one of the oils, Statoil PA, which is a poly(α-olefin) with certain polymers added, no significant difference was found among coulometry using an optimized imidazole-buffered methanolic reagent containing 75% (v/v) chloroform, the two different stripping techniques (working in the temperature interval 100-110 °C), and the commercially available Hydranal Coulomat AG-H. The high stability and sensitivity of the coulometric technique described made it possible to work with sample amounts in the low milligram-range, and this is shown to increase the reliability of the coulometric method as compared to normally used procedures.

  6. Effects of Loading Paths on Hydrodynamic Deep Drawing with Independent Radial Hydraulic Pressure of Aluminum Alloy Based on Numerical Simulation

    Institute of Scientific and Technical Information of China (English)

    Xiaojing LIU; Yongchao XU; Shijian YUAN

    2008-01-01

    In order to meet the forming demands for low plasticity materials and large height-diameter ratio parts, a new process of hydrodynamic deep drawing (HDD) with independent radial hydraulic pressure is proposed. To investigate the effects of loading paths on the HDD with independent radial hydraulic pressure, the forming process of 5A06 aluminum alloy cylindrical cup with a hemispherical bottom was studied by numerical simula- tion. By employing the dynamic explicit analytical software ETA/Dynaform based on LS-DYNA3D, the effects of loading paths on the sheet-thickness distribution and surface quality were analyzed. The corresponding relations of the radial hydraulic pressure loading paths and the part's strain status on the forming limit diagram (FLD) were also discussed. The results indicated that a sound match between liquid chamber pressure and independent radial hydraulic pressure could restrain the serious thinning at the hemisphere bottom and that through adjusting radial hydraulic pressure could reduce the radial tensile strain and change the strain paths. Therefore, the drawing limit of the aluminum cylindrical cup with a hemispherical bottom could be increased significantly.

  7. Standard laboratory hydraulic pressure drop characteristics of various solid and I&E fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Waters, E.D.; Horn, G.R.

    1958-01-20

    The purpose of this report is to present a set of standard pressure-drop curves for various fuel elements in process tubes of Hanford reactors. The flow and pressures within a process tube assembly under normal conditions are dependent to a large extent on the magnitude of the pressure drop across the fuel elements. The knowledge of this pressure drop is important in determination of existing thermal conditions within the process tubes and in predicting conditions for new fuel element designs or changes in operating conditions. The pressure-flow relations for the different Hanford fuel element-process tube assemblies have all been determined at one time or another in the 189-D Hydraulics Laboratory but the data had never been collected into a single report. Such a report is presented now in the interest of establishing a set of ``standard curves`` as determined by laboratory investigations. It must be recognized that the pressure drops of fuel elements in actual process tubes in the reactors may be slightly different than those reported here. The data presented here were obtained in new process tubes while reactor process tubes are usually either corroded or filmed, depending on their past history.

  8. 4D synchrotron X-ray imaging to understand porosity development in shales during exposure to hydraulic fracturing fluid

    Science.gov (United States)

    Kiss, A. M.; Bargar, J.; Kohli, A. H.; Harrison, A. L.; Jew, A. D.; Lim, J. H.; Liu, Y.; Maher, K.; Zoback, M. D.; Brown, G. E.

    2016-12-01

    Unconventional (shale) reservoirs have emerged as the most important source of petroleum resources in the United States and represent a two-fold decrease in greenhouse gas emissions compared to coal. Despite recent progress, hydraulic fracturing operations present substantial technical, economic, and environmental challenges, including inefficient recovery, wastewater production and disposal, contaminant and greenhouse gas pollution, and induced seismicity. A relatively unexplored facet of hydraulic fracturing operations is the fluid-rock interface, where hydraulic fracturing fluid (HFF) contacts shale along faults and fractures. Widely used, water-based fracturing fluids contain oxidants and acid, which react strongly with shale minerals. Consequently, fluid injection and soaking induces a host of fluid-rock interactions, most notably the dissolution of carbonates and sulfides, producing enhanced or "secondary" porosity networks, as well as mineral precipitation. The competition between these mechanisms determines how HFF affects reactive surface area and permeability of the shale matrix. The resultant microstructural and chemical changes may also create capillary barriers that can trap hydrocarbons and water. A mechanistic understanding of the microstructure and chemistry of the shale-HFF interface is needed to design new methodologies and fracturing fluids. Shales were imaged using synchrotron micro-X-ray computed tomography before, during, and after exposure to HFF to characterize changes to the initial 3D structure. CT reconstructions reveal how the secondary porosity networks advance into the shale matrix. Shale samples span a range of lithologies from siliceous to calcareous to organic-rich. By testing shales of different lithologies, we have obtained insights into the mineralogic controls on secondary pore network development and the morphologies at the shale-HFF interface and the ultimate composition of produced water from different facies. These results

  9. Hydraulic pressure variations of groundwater in the Gran Sasso underground laboratory during Amatrice earthquake of August 24th, 2016

    Directory of Open Access Journals (Sweden)

    Gaetano De Luca

    2016-12-01

    Full Text Available Since May 2015, hydraulic pressure, temperature and electrical conductivity of groundwater are in continuos recording near the deep underground laboratories of Gran Sasso of INFN. We used the S13 borehole that have pressure varying in the range of 24-28 bar during the year; these values mean that we have at least 300 m of water table above. The sampling of these parameters was brought until to 50 Hz using a 3 channels 24-bit ADC. During the period May 2015 – September 2016 (17 months we detected hydraulic pressure signals from 12 earthquakes at different surface distances (from 12.000 to 30 km and different magnitudes (from 8.3 to 4.3 Mw. For the Amatrice mainshock, we present, as first results, the hydroseismograph recorded at the S13 hydraulic pressure device compared to the time history recorded at GIGS station located both in the deep core of the Gran Sasso chain.

  10. Prediction of Dynamic Wellbore Pressure in Gasified Fluid Drilling

    Institute of Scientific and Technical Information of China (English)

    Wang Zhiming; Ping Liqiu; Zou Ke

    2007-01-01

    The basis of designing gasified drilling is to understand the behavior of gas/liquid two-phase flow in the wellbore. The equations of mass and momentum conservation and equation of fluid flow in porous media were used to establish a dynamic model to predict weIlbore pressure according to the study results of Ansari and Beggs-Brill on gas-liquid two-phase flow. The dynamic model was solved by the finite difference approach combined with the mechanistic steady state model. The mechanistic dynamic model was numerically implemented into a FORTRAN 90 computer program and could simulate the coupled flow of fluid in wellbore and reservoir. The dynamic model revealed the effects of wellhead back pressure and injection rate of gas/liquid on bottomhole pressure. The model was validated against full-scale experimental data, and its 5.0% of average relative error could satisfy the accuracy requirements in engineering design.

  11. DYNAMIC CHARACTERISTICS OF ELECTRO-HYDRAULIC PROPORTIONAL PRESSURE-FLOW HYBRID VALVE

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The structure principles under the flow and pressure working conditions are studied, in order to investigate the dynamic characteristics of the electro-hydraulic proportional pressure-flow hybrid valve. According to the structure principles under the two different working conditions, the transfer functions under such conditions are derived. With the transfer functions, some structure elements that may affect its performance, are investigated, afterwards some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The conclusions can be used to instruct engineering applications and products designing. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works.

  12. Pressure Control for a Hydraulic Cylinder Based on a Self-Tuning PID Controller Optimized by a Hybrid Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Ru Wang

    2017-01-01

    Full Text Available In order to improve the performance of the hydraulic support electro-hydraulic control system test platform, a self-tuning proportion integration differentiation (PID controller is proposed to imitate the actual pressure of the hydraulic support. To avoid the premature convergence and to improve the convergence velocity for tuning PID parameters, the PID controller is optimized with a hybrid optimization algorithm integrated with the particle swarm algorithm (PSO and genetic algorithm (GA. A selection probability and an adaptive cross probability are introduced into the PSO to enhance the diversity of particles. The proportional overflow valve is installed to control the pressure of the pillar cylinder. The data of the control voltage of the proportional relief valve amplifier and pillar pressure are collected to acquire the system transfer function. Several simulations with different methods are performed on the hydraulic cylinder pressure system. The results demonstrate that the hybrid algorithm for a PID controller has comparatively better global search ability and faster convergence velocity on the pressure control of the hydraulic cylinder. Finally, an experiment is conducted to verify the validity of the proposed method.

  13. Multi-elemental analysis of jet engine lubricating oils and hydraulic fluids and their implication in aircraft air quality incidents.

    Science.gov (United States)

    van Netten, C

    1999-05-07

    The flight crews of aircraft often report symptoms including dizziness, nausea, disorientation, blurred vision and tingling in legs and arms. Many of these incidents have been traced to contamination of cabin air with lubricating oil, as well as hydraulic fluid, constituents. Considering that these air contaminants are often subjected to temperatures in excess of 500 degrees C, a large number of different exposures can be expected. Although the reported symptoms are most consistent with exposures to volatile organic compounds, carbon monoxide, and the organophosphate constituents in these oils and fluids, the involvement of these agents has not been clearly demonstrated. Possible exposure to toxic elements, such as lead, mercury, thallium and others, have not been ruled out. In order to assess the potential of exposure to toxic elements a multi-elemental analysis was done on two hydraulic fluids and three lubricating oils which have been implicated in a number of air quality incidents. A secondary objective was to establish if the multi-elemental concentrations of the fluids tested are different enough to allow such an analysis to be used as a possible method of identifying the source of exposure that might have been present during aircraft air quality incidents. No significant concentrations of toxic elements were identified in any of the oils or hydraulic fluids. The elemental compositions of the samples were different enough to be used for identification purposes and the measurement of only three elements was able to achieve this. Whether these findings have an application, in aircraft air quality incident investigations, needs to be established with further studies.

  14. Comparative Studies of the Short-Term Toxicity of the Hydraulic Fluids MIL-H-19457C, MIL-H-19457B, and MIL-H-22072B.

    Science.gov (United States)

    1986-07-09

    17 COSATI COOGS I. SUOIECT TERMS IConAo Wan @U n I af ecnwy OWd Idenafy by 611"k numberp WIGL GROUP Sue. on. MIL-H-19457C Hydraulic Fluids Neurotoxi ci...GOPSUU.Gp. MIL-H-19457C Hydraulic Fluids Neurotoxi city MIL-H-19457B 21-Day Inhalation Acute Toxicity MIL-H-22072B Ethylene Glycol 1. ?I (CONMu. on ,VVV

  15. Computational Fluid Dynamics Analysis of High Injection Pressure Blended Biodiesel

    Science.gov (United States)

    Khalid, Amir; Jaat, Norrizam; Faisal Hushim, Mohd; Manshoor, Bukhari; Zaman, Izzuddin; Sapit, Azwan; Razali, Azahari

    2017-08-01

    Biodiesel have great potential for substitution with petrol fuel for the purpose of achieving clean energy production and emission reduction. Among the methods that can control the combustion properties, controlling of the fuel injection conditions is one of the successful methods. The purpose of this study is to investigate the effect of high injection pressure of biodiesel blends on spray characteristics using Computational Fluid Dynamics (CFD). Injection pressure was observed at 220 MPa, 250 MPa and 280 MPa. The ambient temperature was kept held at 1050 K and ambient pressure 8 MPa in order to simulate the effect of boost pressure or turbo charger during combustion process. Computational Fluid Dynamics were used to investigate the spray characteristics of biodiesel blends such as spray penetration length, spray angle and mixture formation of fuel-air mixing. The results shows that increases of injection pressure, wider spray angle is produced by biodiesel blends and diesel fuel. The injection pressure strongly affects the mixture formation, characteristics of fuel spray, longer spray penetration length thus promotes the fuel and air mixing.

  16. Dependency of hydromechanical properties of monzonitic granite on confining pressure and fluid pressure under compression

    Science.gov (United States)

    Wang, Huanling; Xu, Weiya; Lui, Zaobao; Chao, Zhiming; Meng, Qingxiang

    2016-05-01

    Monzonitic granite is a low-permeability rock. Monzonitic granite formations are ideal for underground storage of oil due to their low permeability and high mechanical strength. In this study, a series of coupled hydromechanical triaxial tests are carried out using monzonitic granite specimens. The influence of confining and fluid pressures on stress, strain, and permeability is investigated. Failure characteristics under different confining and fluid pressures are discussed based on the analysis of macro fracture planes and micro scanning electron microscopy (SEM). The test results show that the change of permeability with stress and strain reflects the deformation stages of compaction, compression, crack propagation, coalesce, and failure of cracks. Due to the low porosity, the change of permeability is small in the initial phases of compaction and compression, whereas there is a significant increase in permeability when new cracks start to develop and coalesce. Confining pressures have a significant impact on the strength and permeability, particularly the crack damage stress of the rock. Compared with confining pressure, the effect of fluid pressure on rock strength and crack damage stress is small. For the monzonitic granite specimens tested, changing the confining pressure results in different failure modes, whereas the fluid pressure has a relatively small effect on the failure modes.

  17. Syrinx fluid transport: modeling pressure-wave-induced flux across the spinal pial membrane.

    Science.gov (United States)

    Elliott, N S J

    2012-03-01

    Syrinxes are fluid-filled cavities of the spinal cord that characterize syringomyelia, a disease involving neurological damage. Their formation and expansion is poorly understood, which has hindered successful treatment. Syrinx cavities are hydraulically connected with the spinal subarachnoid space (SSS) enveloping the spinal cord via the cord interstitium and the network of perivascular spaces (PVSs), which surround blood vessels penetrating the pial membrane that is adherent to the cord surface. Since the spinal canal supports pressure wave propagation, it has been hypothesized that wave-induced fluid exchange across the pial membrane may play a role in syrinx filling. To investigate this conjecture a pair of one-dimensional (1-d) analytical models were developed from classical elastic tube theory coupled with Darcy's law for either perivascular or interstitial flow. The results show that transpial flux serves as a mechanism for damping pressure waves by alleviating hoop stress in the pial membrane. The timescale ratio over which viscous and inertial forces compete was explicitly determined, which predicts that dilated PVS, SSS flow obstructions, and a stiffer and thicker pial membrane-all associated with syringomyelia-will increase transpial flux and retard wave travel. It was also revealed that the propagation of a pressure wave is aided by a less-permeable pial membrane and, in contrast, by a more-permeable spinal cord. This is the first modeling of the spinal canal to include both pressure-wave propagation along the spinal axis and a pathway for fluid to enter and leave the cord, which provides an analytical foundation from which to approach the full poroelastic problem.

  18. Effect of portal hypertension and duct ligature on pancreatic fluid pressures in cats

    DEFF Research Database (Denmark)

    Ebbehøj, N; Borly, L; Heyeraas, K J

    1990-01-01

    In two groups of cats recordings were performed, during laparotomy, of pancreatic tissue fluid pressure measured by a needle technique, interstitial fluid pressure measured by micropipette technique, pancreatic intraductal pressure, and portal vein pressure. In one group of cats the pressures were...... measured before and after acutely induced portal hypertension; in the other group of cats the pressures were measured after an overnight ligature of the pancreatic main duct. At rest the needle pressure was equal to duct pressure but significantly lower than interstitial fluid pressure and portal pressure....... Acute portal hypertension caused no significant changes in micropipette, needle, or duct pressures. Pancreatic duct ligature increased duct pressure, interstitial fluid pressure, and needle pressure. We conclude that the fluid pressure in the pancreas is probably influenced by the production...

  19. Research program: The investigation of heat transfer and fluid flow at low pressure

    Science.gov (United States)

    El-Genk, M. S.; Philbin, J. S.; Foushee, F. C.

    1986-04-01

    This paper gives an overview of a multiyear joint research program being conducted at the University of New Mexico (UNM) with support from Sandia National Laboratories and GA Technologies. This research focuses on heat removal and fluid dynamics in flow regimes characterized by low pressure and low Reynolds number. The program was motivated by a desire to characterize and analyze cooling in a broad class of TRIGA-type reactors under: (1) typical operating conditions, (2) anticipated, new operating regimes, and (3) postulated accident conditions. It has also provided experimental verification of analytical tools used in design analysis. The paper includes descriptions of the UNM thermal-hydraulics test facility and the experimental test sections. During the first two years experiments were conducted using single, electrically heated rod in water and air annuli. This configuration provides an observable and serviceable simulation of a fuel rod and its coolant channel.

  20. Thermal effects on fluid flow and hydraulic fracturing from wellbores and cavities in low-permeability formations

    Energy Technology Data Exchange (ETDEWEB)

    Yarlong Wang [Petro-Geotech Inc., Calgary, AB (Canada); Papamichos, Euripides [IKU Petroleum Research, Trondheim (Norway)

    1999-07-01

    The coupled heat-fluid-stress problem of circular wellbore or spherical cavity subjected to a constant temperature change and a constant fluid flow rate is considered. Transient analytical solutions for temperature, pore pressure and stress are developed by coupling conductive heat transfer with Darcy fluid flow in a poroelastic medium. They are applicable to lower permeability porous media suitable for liquid-waste disposal and also simulating reservoir for enhanced oil recovery, where conduction dominates the heat transfer process. A full range of solutions is presented showing separately the effects of temperature and fluid flow on pore pressure and stress development. It is shown that injection of warm fluid can be used to restrict fracture development around wellbores and cavities and generally to optimise a fluid injection operation. Both the limitations of the solutions and the convective flow effect are addressed. (Author)

  1. Damping Force Modeling and Suppression of Self-Excited Vibration due to Magnetic Fluids Applied in the Torque Motor of a Hydraulic Servovalve

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2017-05-01

    Full Text Available As a key component of hydraulic control systems, hydraulic servovalves influence their performance significantly. Unpredictable self-excited noise inside hydraulic servovalves may cause instability and even failure. Being functional, with higher saturation magnetization and increased viscosity when exposed to a magnetic field, magnetic fluids (MFs have been widely used in dampers, sealing, and biomedical treatment. In this paper, magnetic fluids are applied in the torque motor of a hydraulic servovalve to exert damping and resistance for vibration and noise suppression. Construction of the torque motor armature with magnetic fluids is introduced and the forces due to magnetic fluids on the torque motor armature are studied. Based on a bi-viscosity-constituted relationship, a mathematical model of the damping force from magnetic fluids is built when magnetic fluids are filled in the working gaps of the torque motor. Measurements of the properties of an Fe3O4 composite magnetic fluid are carried out to calculate the parameters of this mathematical model and to investigate the influence of magnetic fluids on the vibration characteristics of the armature assembly. The simulated and tested harmonic responses of the armature with and without magnetic fluids show the good suppression effects of magnetic fluids on the self-excited noise inside the servovalve.

  2. Validation of an All-Pressure Fluid Drop Model: Heptane Fluid Drops in Nitrogen

    Science.gov (United States)

    Harstad, K.; Bellan, J.; Bulzan, Daniel L. (Technical Monitor)

    2000-01-01

    Despite the fact that supercritical fluids occur both in nature and in industrial situations, the fundamentals of their behavior is poorly understood because supercritical fluids combine the characteristics of both liquids and gases, and therefore their behavior is not intuitive. There are several specific reasons for the lack of understanding: First, data from (mostly optical) measurements can be very misleading because regions of high density thus observed are frequently identified with liquids. A common misconception is that if in an experiment one can optically identify "drops" and "ligaments", the observed fluid must be in a liquid state. This inference is incorrect because in fact optical measurements detect any large change (i.e. gradients) in density. Thus, the density ratio may be well below Omicron(10(exp 3)) that characterizes its liquid/gas value, but the measurement will still identify a change in the index of refraction providing that the change is sudden (steep gradients). As shown by simulations of supercritical fluids, under certain conditions the density gradients may remain large during the supercritical binary fluids mixing, thus making them optically identifiable. Therefore, there is no inconsistency between the optical observation of high density regions and the fluids being in a supercritical state. A second misconception is that because a fluid has a liquid-like density, it is appropriate to model it as a liquid. However, such fluids may have liquid-like densities while their transport properties differ from those of a liquid. Considering that the critical pressure of most fuel hydrocarbons used in Diesel and gas turbine engines is in the range of 1.5 - 3 MPa, and the fact that the maximum pressure attained in these engines is about 6 Mps, it is clear that the fuel in the combustion chamber will experience both subcritical and supercritical conditions. Studies of drop behavior over a wide range of pressures were performed in the past

  3. Numerical Study of Thermal Hydraulic behavior of Pressurizer for PLCS Scenario by CUPID Code

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Ryong; Yoon, Han Young [KAERI, Daejeon (Korea, Republic of); Yoon, Bo Kam; Kim, Jeong Ju; Park, Jong Cheol; Lee, Gyu Cheon [KEPCO, Daejeon (Korea, Republic of)

    2016-05-15

    For a malfunction of a pressurizer level control system, a chemical and volume control system (CVCS) charging flowrate becomes a maximum level and a letdown flowrate a minimum level as well. Consequently, a water level and pressure of pressurizer is abnormally increased, which causes a pilot operated relief valve (POSRV) opened. It becomes important to investigate that a mixture from the POSRV becomes single-phase gas or two-phase mixture. In this study, the three-dimensional thermal-hydraulic behavior inside the pressurizer is numerically investigated by the CUPID code. The flow fields highly depend on some parameters such as subcooling of the stored water, interfacial drag model and POSRV opening. Thus, these parameters are examined in this study. These parameters are examined in this study. Less subcooling temperature makes the flow behavior unstable and flashing occur. The two-phase mixture is discharged through the POSRV. Moreover, less flow area delays a discharging flow rate. A sensitivity for the other parameters such critical flow model should be examined for the future work.

  4. Subchannel analysis with turbulent mixing rate of supercritical pressure fluid

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jianhui, E-mail: wjianhui1985@gmail.com [Department of Applied Physics, Waseda University, Tokyo 169-8555 (Japan); Oka, Yoshiaki [Emeritus Professor the University of Tokyo, Tokyo (Japan)

    2015-06-15

    Highlights: • Subchannel analysis with turbulent mixing rate law of supercritical pressure fluid (SPF) is carried out. • Turbulent mixing rate is enhanced, compared with that calculated by the law of pressurized water reactor (PWR). • Increase in maximum cladding surface temperature (MCST) is smaller comparing with PWR model. • The sensitivities of MCST on non-uniformity of subchannel area and power peaking are reduced by using SPF model. - Abstract: The subchannel analysis with turbulent mixing rate law of supercritical pressure fluid (SPF) is carried out for supercritical-pressurized light water cooled and moderated reactor (Super LWR). It is different from the turbulent mixing rate law of pressurized water reactor (PWR), which is widely adopted in Super LWR subchannel analysis study, the density difference between adjacent subchannels is taken into account for turbulent mixing rate law of SPF. MCSTs are evaluated on three kinds of fuel assemblies with different pin power distribution patterns, gap spacings and mass flow rates. Compared with that calculated by employing turbulent mixing rate law of PWR, the increase in MCST is smaller even when peaking factor is large and gap spacing is uneven. The sensitivities of MCST on non-uniformity of the subchannel area and power peaking are reduced.

  5. A systematic evaluation of chemicals in hydraulic-fracturing fluids and wastewater for reproductive and developmental toxicity.

    Science.gov (United States)

    Elliott, Elise G; Ettinger, Adrienne S; Leaderer, Brian P; Bracken, Michael B; Deziel, Nicole C

    2017-01-01

    Hydraulic-fracturing fluids and wastewater from unconventional oil and natural gas development contain hundreds of substances with the potential to contaminate drinking water. Challenges to conducting well-designed human exposure and health studies include limited information about likely etiologic agents. We systematically evaluated 1021 chemicals identified in hydraulic-fracturing fluids (n=925), wastewater (n=132), or both (n=36) for potential reproductive and developmental toxicity to triage those with potential for human health impact. We searched the REPROTOX database using Chemical Abstract Service registry numbers for chemicals with available data and evaluated the evidence for adverse reproductive and developmental effects. Next, we determined which chemicals linked to reproductive or developmental toxicity had water quality standards or guidelines. Toxicity information was lacking for 781 (76%) chemicals. Of the remaining 240 substances, evidence suggested reproductive toxicity for 103 (43%), developmental toxicity for 95 (40%), and both for 41 (17%). Of these 157 chemicals, 67 had or were proposed for a federal water quality standard or guideline. Our systematic screening approach identified a list of 67 hydraulic fracturing-related candidate analytes based on known or suspected toxicity. Incorporation of data on potency, physicochemical properties, and environmental concentrations could further prioritize these substances for future drinking water exposure assessments or reproductive and developmental health studies.

  6. A reactive transport modelling approach to assess the leaching potential of hydraulic fracturing fluids associated with coal seam gas extraction

    Science.gov (United States)

    Mallants, Dirk; Simunek, Jirka; Gerke, Kirill

    2015-04-01

    Coal Seam Gas production generates large volumes of "produced" water that may contain compounds originating from the use of hydraulic fracturing fluids. Such produced water also contains elevated concentrations of naturally occurring inorganic and organic compounds, and usually has a high salinity. Leaching of produced water from storage ponds may occur as a result of flooding or containment failure. Some produced water is used for irrigation of specific crops tolerant to elevated salt levels. These chemicals may potentially contaminate soil, shallow groundwater, and groundwater, as well as receiving surface waters. This paper presents an application of scenario modelling using the reactive transport model for variably-saturated media HP1 (coupled HYDRUS-1D and PHREEQC). We evaluate the fate of hydraulic fracturing chemicals and naturally occurring chemicals in soil as a result of unintentional release from storage ponds or when produced water from Coal Seam Gas operations is used in irrigation practices. We present a review of exposure pathways and relevant hydro-bio-geo-chemical processes, a collation of physico-chemical properties of organic/inorganic contaminants as input to a set of generic simulations of transport and attenuation in variably saturated soil profiles. We demonstrate the ability to model the coupled processes of flow and transport in soil of contaminants associated with hydraulic fracturing fluids and naturally occurring contaminants.

  7. Essentials of fluid dynamics with applications to hydraulics, aeronautics, meteorology and other subjets

    CERN Document Server

    Prandtl, Ludwig

    1953-01-01

    Equilibrium of liquids and gases ; kinematics : dynamics of frictionless fluids ; motion of viscous fluids : turbulence : fluid resistance : practical applications ; flow with appreciable volume changes (dynamics of gases) ; miscellaneous topics.

  8. Hydraulic wind energy conversion system

    Energy Technology Data Exchange (ETDEWEB)

    1981-07-01

    The purpose of this research was to design, build and test a hydraulic wind energy system. This design used a three bladed turbine, which drove a hydraulic pump. The energy is transmitted from the pump through a long hose and into a hydraulic motor, where the energy is used. This wind system was built and tested during the winter of 1980-1981. The power train included a five meter, three bladed wind turbine, a 9.8:1 ratio gearbox, a 1.44 cubic inch displacement pump with a small supercharge gear pump attached. The hydraulic fluid was pumped through a 70', 3/4'' I-D-high pressure flexhose, then through a volume control valve and into a 1.44 cubic inch displacement motor. The fluid was returned through a 70', 1'' I-D-flexhose.

  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. Using the Casson model in a rheological and hydraulic evaluation of wash fluids

    Energy Technology Data Exchange (ETDEWEB)

    Dorman, J.

    1984-01-01

    The Ostwald de Waale or Robertson Stiff rheological models or their variants with corrections for temperature are convenient for determining the hydraulic drilling parameters. A series of examples is cited.

  11. 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.

  12. HYDRAULIC PRESSURE SIGNAL DENOISING USING THRESHOLD SELF-LEARNING WAVELET ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    GUO Xin-lei; YANG Kai-lin; GUO Yong-xin

    2008-01-01

    A pre-filter combined with threshold self-learning wavelet algorithm is proposed for hydraulic pressure signals denoising. The denoising threshold is self-learnt in the steady flow state, and then modified under a given limit to make the mean square errors between reconstruction signals and desirable outputs minimum, so the corresponding optimal denoising threshold in a single operating case can be obtained. These optimal thresholds are used for the whole signal denoising and are different in various cases. Simulation results and comparative studies show that the present approach has an obvious effect of noise suppression and is superior to those of traditional wavelet algorithms and back-propagation neural networks. It also provides the precise data for the next step of pipeline leak detection using transient technique.

  13. Numerical simulation of blood flow and interstitial fluid pressure in solid tumor microcirculation based on tumor-induced angiogenesis

    Science.gov (United States)

    Zhao, Gaiping; Wu, Jie; Xu, Shixiong; Collins, M. W.; Long, Quan; König, Carola S.; Jiang, Yuping; Wang, Jian; Padhani, A. R.

    2007-10-01

    A coupled intravascular transvascular interstitial fluid flow model is developed to study the distributions of blood flow and interstitial fluid pressure in solid tumor microcirculation based on a tumor-induced microvascular network. This is generated from a 2D nine-point discrete mathematical model of tumor angiogenesis and contains two parent vessels. Blood flow through the microvascular network and interstitial fluid flow in tumor tissues are performed by the extended Poiseuille’s law and Darcy’s law, respectively, transvascular flow is described by Starling’s law; effects of the vascular permeability and the interstitial hydraulic conductivity are also considered. The simulation results predict the heterogeneous blood supply, interstitial hypertension and low convection on the inside of the tumor, which are consistent with physiological observed facts. These results may provide beneficial information for anti-angiogenesis treatment of tumor and further clinical research.

  14. An improved technique for studying pleural fluid pressure and composition in rabbits.

    Science.gov (United States)

    Del Fabbro, M

    1998-07-01

    Knowledge of pleural liquid pressure (Pliq) and composition is crucial for studies concerning intrapleural fluid dynamics, and pleural fluid turnover. We measured Pliq at intercostal and costal levels in anaesthetized spontaneously breathing rabbits using a minimally invasive method that assures a long-lasting hydraulic continuity between the pleural liquid and the recording system. Polyethylene tubes were glued either to the exposed endothoracic fascia or inserted into a rib to provide a scaled connection to the recording system. After inducing a pneumothorax with nitrous oxide (N2O) via an intrapleural cannula, a hole (approximately 0.7 mm2) was pierced in the parietal pleura through the tube lumen. The tubes were then connected to pressure transducers and the whole system was filled with heparinized saline to the level of the parietal pleura; finally the pneumo-thorax was removed after N2O washout and Pliq recordings were performed. A different kind of tube was used to obtain microsamples of pleural fluid (2.5-3 microliters) during spontaneous breathing; colloid osmotic pressure of the microsamples (pi liq) was measured with an osmometer, and averaged 9.3 +/- 1.5 cm H2o (n = 70 samples). When pooled and plotted against lung height end-expiratory intercostal and costal Pliq data scattered along a single regression line with a slope of -0.83 and -0.90 cm H2O cm(-1) in supine and prone animals, respectively. End-inspiratory costal Pliq was significantly more subatmospheric than intercostal in the ventral region of the chest (P dynamics and turnover.

  15. Effect of portal hypertension and duct ligature on pancreatic fluid pressures in cats

    DEFF Research Database (Denmark)

    Ebbehøj, N; Borly, L; Heyeraas, K J

    1990-01-01

    In two groups of cats recordings were performed, during laparotomy, of pancreatic tissue fluid pressure measured by a needle technique, interstitial fluid pressure measured by micropipette technique, pancreatic intraductal pressure, and portal vein pressure. In one group of cats the pressures were...... measured before and after acutely induced portal hypertension; in the other group of cats the pressures were measured after an overnight ligature of the pancreatic main duct. At rest the needle pressure was equal to duct pressure but significantly lower than interstitial fluid pressure and portal pressure...

  16. A decision analysis framework for estimating the potential hazards for drinking water resources of chemicals used in hydraulic fracturing fluids.

    Science.gov (United States)

    Yost, Erin E; Stanek, John; Burgoon, Lyle D

    2017-01-01

    Despite growing concerns over the potential for hydraulic fracturing to impact drinking water resources, there are limited data available to identify chemicals used in hydraulic fracturing fluids that may pose public health concerns. In an effort to explore these potential hazards, a multi-criteria decision analysis (MCDA) framework was employed to analyze and rank selected subsets of these chemicals by integrating data on toxicity, frequency of use, and physicochemical properties that describe transport in water. Data used in this analysis were obtained from publicly available databases compiled by the United States Environmental Protection Agency (EPA) as part of a larger study on the potential impacts of hydraulic fracturing on drinking water. Starting with nationwide hydraulic fracturing chemical usage data from EPA's analysis of the FracFocus Chemical Disclosure Registry 1.0, MCDAs were performed on chemicals that had either noncancer toxicity values (n=37) or cancer-specific toxicity values (n=10). The noncancer MCDA was then repeated for subsets of chemicals reported in three representative states (Texas, n=31; Pennsylvania, n=18; and North Dakota, n=20). Within each MCDA, chemicals received scores based on relative toxicity, relative frequency of use, and physicochemical properties (mobility in water, volatility, persistence). Results show a relative ranking of these chemicals based on hazard potential, and provide preliminary insight into chemicals that may be more likely than others to impact drinking water resources. Comparison of nationwide versus state-specific analyses indicates regional differences in the chemicals that may be of more concern to drinking water resources, although many chemicals were commonly used and received similar overall hazard rankings. Several chemicals highlighted by these MCDAs have been reported in groundwater near areas of hydraulic fracturing activity. This approach is intended as a preliminary analysis, and represents one

  17. Synthesis and evaluation of C-ether formulations for use as high temperature lubricants and hydraulic fluids

    Science.gov (United States)

    Clark, F. S.; Green, R. L.; Miller, D. R.

    1974-01-01

    The formulation and evaluation of C-ether fluids for use in the hydraulic and lubrication systems of the space shuttle and advanced air breathing engines were studied to lower the pour point of a reference C-ether from -29 C to -40 C without changing its evaporation loss. Use of disiloxanes mixed with C-ethers gave a -40 C pour point fluid with little change in the desired evaporation loss or in oxidative stability. A second -40 C pour point fluid containing only C-ethers was also developed. A screening program tested lubrication additives for C-ethers and the new fluids. Six additive packages were chosen for evaluation in 316 C bearing tests, two for evaluation in 260 C pump tests. The goal of the bearing test was a 100 hour run. The rig was a specially designed 80-mm axially loaded ball bearing. The C-ether base fluid ran only one hour at 316 C before cage wear failure occurred. The best additive blends ran 47, 94 and 100 hours. The 96 hour test gave excessive deposits. The 100 hour test had no wear failures; an unexplained loss of cage silver occurred from areas of direct fluid impingement on the cage.

  18. HYDRAULIC SERVO

    Science.gov (United States)

    Wiegand, D.E.

    1962-05-01

    A hydraulic servo is designed in which a small pressure difference produced at two orifices by an electrically operated flapper arm in a constantly flowing hydraulic loop is hydraulically amplified by two constant flow pumps, two additional orifices, and three unconnected ball pistons. Two of the pistons are of one size and operate against the additional orifices, and the third piston is of a different size and operates between and against the first two pistons. (AEC)

  19. Anisotropic pressure molecular dynamics for atomic fluid systems

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Bastida, M [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Avenida Universidad 1001, Chamilpa, Cuernavaca, Morelos 62209 (Mexico); Lopez-Rendon, R [Departamento de QuImica, Universidad Autonoma Metropolitana-Iztapalapa, Av San Rafael Atlixco 186, 09340 Mexico DF (Mexico)

    2007-07-20

    The MTK equations (Martyna G J, Tobias D J and Klein M L 1994 J. Chem. Phys. 101 4177-89), which simulate the constant-pressure, constant-temperature NPT ensemble, have been modified to simulate an anisotropic pressure along a single coordinate axis, thus rendering the NP{sub zz}T ensemble. The necessary theory of non-Hamiltonian systems is briefly reviewed in order to analytically prove that the proposed equations indeed sample the desired ensemble. A previously derived geometric integrator for the MTK equations is modified to take into account the anisotropic pressure and volume fluctuations. We choose a Lennard-Jones fluid as an illustrative example. The density distribution function, as well as various thermodynamic and interfacial properties of the model system in a liquid-vapour coexistence state, was computed to test the robustness of the proposed equations of motion to simulate the NP{sub zz}T ensemble.

  20. Asymmetric fluid criticality. I. Scaling with pressure mixing.

    Science.gov (United States)

    Kim, Young C; Fisher, Michael E; Orkoulas, G

    2003-06-01

    The thermodynamic behavior of a fluid near a vapor-liquid and, hence, asymmetric critical point is discussed within a general "complete" scaling theory incorporating pressure mixing in the nonlinear scaling fields as well as corrections to scaling. This theory allows for a Yang-Yang anomaly in which mu(")(sigma)(T), the second temperature derivative of the chemical potential along the phase boundary, diverges like the specific heat when T-->T(c); it also generates a leading singular term, /t/(2beta), in the coexistence curve diameter, where t[triple bond](T-T(c))/T(c). The behavior of various special loci, such as the critical isochore, the critical isotherm, the k-inflection loci, on which chi((k))[triple bond]chi(rho,T)/rho(k) (with chi=rho(2)k(B)TK(T)) and C((k))(V)[triple bond]C(V)(rho,T)/rho(k) are maximal at fixed T, is carefully elucidated. These results are useful for analyzing simulations and experiments, since particular, nonuniversal values of k specify loci that approach the critical density most rapidly and reflect the pressure-mixing coefficient. Concrete illustrations are presented for the hard-core square-well fluid and for the restricted primitive model electrolyte. For comparison, a discussion of the classical (or Landau) theory is presented briefly and various interesting loci are determined explicitly and illustrated quantitatively for a van der Waals fluid.

  1. Alternative blade materials for technical and ecological optimization of a hydraulic pressure machine

    Science.gov (United States)

    Schwyzer, Olivier; Saenger, Nicole

    2016-11-01

    The Hydraulic Pressure Machine (HPM) is an energy converter to exploit head differences between 0.5 and 2.5 m in small streams and irrigation canals. Previous investigations show that efficiencies above 60% are possible. Several case studies indicate good continuity for aquatic life (e.g. fish) and bed load for the technology. The technology is described as an economically and ecologically viable option for small scale hydropower generation. Primary goal of this research is to improve the HPM blade design regarding its continuity properties by maintaining good efficiency rates. This is done by modifying the blade tip and testing within a large physical model under laboratory condition. Blade tips from steel (conventional - reference case) and a combination of EPDM rubber and steel as sandwich construction (rubber, steel, rubber - adhesive layered) are tested and compared. Both materials reach similar values for hydraulic efficiency (approx. 58%) and mechanical power output (approx. 220 W). The variation of different gap sizes pointed out the importance of small clearance gaps to reach high efficiencies. For assessing the two blade tip materials regarding continuity for aquatic life, fish dummies were led through the wheel. Analysis of slow motion video of dummies hit by the blade show significant advantages for the EPDM blade tip. The EPDM rubber allows to bend and thus reduces the shock and the probability for cuts on the fish dummy. It was shown that blade tips from EPDM have certain advantages regarding continuity compared to standard blade tips from steel. No compromise regarding energy production had to be made. These results from the HPM can be transferred to breast shot water wheel and may be applied for new and retrofitting projects.

  2. A new pressure-parametrization unified dark fluid model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Deng [Nankai University, Theoretical Physics Division, Chern Institute of Mathematics, Tianjin (China); Yan, Yang-Jie; Meng, Xin-He [Nankai University, Department of Physics, Tianjin (China)

    2017-04-15

    We propose a new pressure-parametrization model to explain the accelerated expansion of the late-time Universe by considering the baryon matter and dark contents (dark matter and dark energy) as a unified dark fluid. To realize this model more physically, we reconstruct it with the quintessence and phantom scalar fields, respectively. We use the recent cosmological data to constrain this model, distinguish it from the standard cosmological model and find that the value of the Hubble constant H{sub 0} = 68.34{sup +0.53}{sub -0.92} supports the global measurement by the Planck satellite at the 1σ confidence level. (orig.)

  3. A Procedure for Measuring Microplastics using Pressurized Fluid Extraction.

    Science.gov (United States)

    Fuller, Stephen; Gautam, Anil

    2016-06-07

    A method based on pressurized fluid extraction (PFE) was developed for measuring microplastics in environmental samples. This method can address some limitations of the current microplastic methods and provide laboratories with a simple analytical method for quantifying common microplastics in a range of environmental samples. The method was initially developed by recovering 101% to 111% of spiked plastics on glass beads and was then applied to a composted municipal waste sample with spike recoveries ranging from 85% to 94%. The results from municipal waste samples and soil samples collected from an industrial area demonstrated that the method is a promising alternative for determining the concentration and identity of microplastics in environmental samples.

  4. 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...

  5. Fluctuations of Quantum Radiation Pressure in Dissipative Fluid

    CERN Document Server

    Wu, C H; Wu, Chun-Hsien; Lee, Da-Shin

    2003-01-01

    Using the generalized Langevin equations involving the stress tensor approach, quantum fluctuations of electromagnetic radiation pressure in the presence of a dissipative environment have been studied. We consider a perfectly reflecting mirror which is exposed to the electromagnetic radiation pressure in a fluid at finite temperature. The dynamics of velocity fluctuations of the mirror is studied analytically in both small time and large time limits. In the small time limit, the minimum uncertainty of the mirror's position measurement from both quantum and thermal noises effects including the photon counting error in the laser interferometer is obtained based on the fluctuation-dissipation theorem as compared with the ''standard quantum limit''. In addition, the result of the large time behavior of fluctuations of the mirror's velocity in a dissipative environment can be applied to the laser interferometer of the ground-based gravitational wave detector. The role of the dissipative effects in this case is pla...

  6. Chloride concentration gradients in tank-stored hydraulic fracturing fluids following flowback

    Science.gov (United States)

    Pamela J. Edwards; Linda L. Tracy; William K. Wilson

    2011-01-01

    A natural gas well in West Virginia was hydraulically fractured and the flowback was recovered and stored in an 18-foot-deep tank. Both in situ field test kit and laboratory measurements of electrical conductivity and chloride concentrations increased substantially with depth, although the laboratory measurements showed a greater increase. The field test kit also...

  7. Analytical Thermal Field Theory Applicable to Oil Hydraulic Fluid Film Lubrication

    DEFF Research Database (Denmark)

    Johansen, Per; Roemer, Daniel Beck; Pedersen, Henrik C.

    2014-01-01

    An analytical thermal field theory is derived by a perturbation series expansion solution to the energy conservation equation. The theory is valid for small values of the Brinkman number and the modified Peclet number. This condition is sufficiently satisfied for hydraulic oils, whereby the analy...

  8. Degradation of Phosphate Ester Hydraulic Fluid in Power Station Turbines Investigated by a Three-Magnet Unilateral Magnet Array

    Directory of Open Access Journals (Sweden)

    Pan Guo

    2014-04-01

    Full Text Available A three-magnet array unilateral NMR sensor with a homogeneous sensitive spot was employed for assessing aging of the turbine oils used in two different power stations. The Carr-Purcell-Meiboom-Gill (CPMG sequence and Inversion Recovery-prepared CPMG were employed for measuring the 1H-NMR transverse and longitudinal relaxation times of turbine oils with different service status. Two signal components with different lifetimes were obtained by processing the transverse relaxation curves with a numeric program based on the Inverse Laplace Transformation. The long lifetime components of the transverse relaxation time T2eff and longitudinal relaxation time T1 were chosen to monitor the hydraulic fluid aging. The results demonstrate that an increase of the service time of the turbine oils clearly results in a decrease of T2eff,long and T1,long. This indicates that the T2eff,long and T1,long relaxation times, obtained from the unilateral magnetic resonance measurements, can be applied as indices for degradation of the hydraulic fluid in power station turbines.

  9. Research on Pressure Shock in Hydraulic System%液压系统中的压力冲击研究

    Institute of Scientific and Technical Information of China (English)

    杨斌

    2016-01-01

    Based on theoretical calculation and simulation analysis, this paper got the key factor which affect the pressure shock in valve-control hydraulic system. Then concluded how the tube length and valve open-time affect pressure shock in hydraulic system. And the conclusions were verified based on test. It showed that tube length and valve open-time affect pressure shock in hydraulic system directly. The research also showed that shortening tube length and increasing valve open-time properly can reduce pressure shock effectively. All above provide the direction for the layout and design of hydraulic system part/product, and also provide theoretical basis for optimizing hydraulic system.%通过理论计算和仿真分析,研究影响阀控液压系统压力冲击的关键因素,得出阀控液压系统中的压力冲击与管路长度、阀开启时间的关系,并进行试验验证。结果表明,管路长度、阀开启时间直接影响着阀控液压系统中的压力冲击。缩短管路长度和适当延长阀开启时间,都能有效减小阀控系统中的压力冲击。这为飞机液压系统中元部件的布局和设计提供了方向,为飞机液压系统的完善和优化提供了依据。

  10. Computational fluid dynamics modelling of cerebrospinal fluid pressure in Chiari malformation and syringomyelia.

    Science.gov (United States)

    Clarke, Elizabeth C; Fletcher, David F; Stoodley, Marcus A; Bilston, Lynne E

    2013-07-26

    The pathogenesis of syringomyelia in association with Chiari malformation (CM) is unclear. Studies of patients with CM have shown alterations in the CSF velocity profile and these could contribute to syrinx development or enlargement. Few studies have considered the fluid mechanics of CM patients with and without syringomyelia separately. Three subject-specific CFD models were developed for a normal participant, a CM patient with syringomyelia and a CM patient without syringomyelia. Model geometries, CSF flow rate data and CSF velocity validation data were collected from MRI scans of the 3 subjects. The predicted peak CSF pressure was compared for the 3 models. An extension of the study performed geometry and flow substitution to investigate the relative effects of anatomy and CSF flow profile on resulting spinal CSF pressure. Based on 50 monitoring locations for each of the models, the CM models had significantly higher magnitude (psyringomyelia mechanisms and relative effects of CSF velocity profile and spinal geometry on CSF pressure.

  11. Hydro-mechanical pressure response to fluid injection into finite aquifers highlights the non-local behavior of storage

    Science.gov (United States)

    De Simone, Silvia; Carrera, Jesus

    2017-04-01

    Specific storage reflects the volumetric deformation capacity of permeable media. Classical groundwater hydrology equals elastic storage to medium compressibility, which is a constant-in-time and locally-defined parameter. This allows simplifying the flow equation into a linear diffusion equation that is relatively easy to solve. However, the hydraulic gradients, generated by fluid injection or pumping, act as forces that push the medium in the direction of flow causing it to deform, even in regions where pressure has not changed. Actual deformation depends on the elastic properties of the medium, but also on aquifer geometry and on surrounding strata, which act like constraints to displacements. Therefore the storage results to be non-local (i.e., the volume of water released at a point depends on the poroelastic response over the whole aquifer) and the proper evaluation of transient pressure requires acknowledging the hydro-mechanical (HM) coupling, which is generally disregarded by conventional hydrogeology. Here we discuss whether HM coupling effects are relevant, which is of special interest for the activities of enhanced geothermics, waste disposal, CO2 storage or shale gas extraction. We propose analytic solutions to the HM problem of fluid injection (or extraction) into finite aquifers with one-dimensional or cylindrical geometries. We find that the deviation respect to traditional purely hydraulic solutions is significant when the aquifer has limited capacity to deform. The most relevant implications are that the response time is faster and the pressure variation greater than expected, which may be relevant for aquifer characterization and for the evaluation of pressure build-up due to fluid injection.

  12. DESIGN OF NOVEL HIGH PRESSURE- RESISTANT HYDROTHERMAL FLUID SAMPLE VALVE

    Institute of Scientific and Technical Information of China (English)

    LIU Wei; YANG Canjun; WU Shijun; XIE Yingjun; CHEN Ying

    2008-01-01

    Sampling study is an effective exploration method, but the most extreme environments of hydrothermal vents pose considerable engineering challenges for sampling hydrothermal fluids. Moreover, traditional sampler systems with sample valves have difficulty in maintaining samples in situ pressure. However, decompression changes have effect on microorganisms sensitive to such stresses. To address the technical difficulty of collecting samples from hydrothermal vents, a new bidirectional high pressure-resistant sample valve with balanced poppet was designed. The sample valve utilizes a soft high performance plastic "PEEK" as poppet. The poppet with inapposite dimension is prone to occur to plastic deformation or rupture for high working pressure in experiments. To address this issue, based on the finite element model, simulated results on stress distribution of the poppet with different structure parameters and preload spring force were obtained. The static axial deformations on top of the poppet were experimented. The simulated results agree with the experimental results. The new sample valve seals well and it can withstand high working pressure.

  13. Transport efficiency and dynamics of hydraulic fracture networks

    Science.gov (United States)

    Sachau, Till; Bons, Paul; Gomez-Rivas, Enrique

    2015-08-01

    Intermittent fluid pulses in the Earth's crust can explain a variety of geological phenomena, for instance the occurrence of hydraulic breccia. Fluid transport in the crust is usually modeled as continuous darcian flow, ignoring that sufficient fluid overpressure can cause hydraulic fractures as fluid pathways with very dynamic behavior. Resulting hydraulic fracture networks are largely self-organized: opening and healing of hydraulic fractures depends on local fluid pressure, which is, in turn, largely controlled by the fracture network. We develop a crustal-scale 2D computer model designed to simulate this process. To focus on the dynamics of the process we chose a setup as simple as possible. Control factors are constant overpressure at a basal fluid source and a constant 'viscous' parameter controlling fracture-healing. Our results indicate that at large healing rates hydraulic fractures are mobile, transporting fluid in intermittent pulses to the surface and displaying a 1/fα behavior. Low healing rates result in stable networks and constant flow. The efficiency of the fluid transport is independent from the closure dynamics of veins or fractures. More important than preexisting fracture networks is the distribution of fluid pressure. A key requirement for dynamic fracture networks is the presence of a fluid pressure gradient.

  14. Transport efficiency and dynamics of hydraulic fracture networks

    Directory of Open Access Journals (Sweden)

    Till eSachau

    2015-08-01

    Full Text Available Intermittent fluid pulses in the Earth's crust can explain a variety of geological phenomena, for instance the occurrence of hydraulic breccia. Fluid transport in the crust is usually modeled as continuous darcian flow, ignoring that sufficient fluid overpressure can cause hydraulic fractures as fluid pathways with very dynamic behavior. Resulting hydraulic fracture networks are largely self-organized: opening and healing of hydraulic fractures depends on local fluid pressure, which is, in turn, largely controlled by the fracture network. We develop a crustal-scale 2D computer model designed to simulate this process. To focus on the dynamics of the process we chose a setup as simple as possible. Control factors are constant overpressure at a basal fluid source and a constant 'viscous' parameter controlling fracture-healing. Our results indicate that at large healing rates hydraulic fractures are mobile, transporting fluid in intermittent pulses to the surface and displaying a 1/fα behavior. Low healing rates result in stable networks and constant flow. The efficiency of the fluid transport is independent from the closure dynamics of veins or fractures. More important than preexisting fracture networks is the distribution of fluid pressure. A key requirement for dynamic fracture networks is the presence of a fluid pressure gradient.

  15. Robust pressure sensor for measurements in boundary layers of liquid fluids with medium total pressures

    Science.gov (United States)

    Beutel, T.; Ferreira, N.; Leester-Schädel, M.; Büttgenbach, S.

    2011-06-01

    In this work, the latest results of the design, fabrication and characterization of a new MEMS piezoresistive pressure sensor are presented. It is made of silicon using a boron diffusion process to create piezoresistors. Significant changes in the layout as well as in the micro-fabrication process have been made, e.g. anodic bonding of a Pyrex cover on the backside. These lead to a very precise pressure sensor, which is tailor made for high dynamic measurements in fluids with a total pressure up to 4 bar. This new piezoresistive pressure sensor has been developed in order to meet the special requirements of measurements in fluid mechanics, particularly with regard to the non-intrusive nature of the sensor. The sensor development, starting with the simulation of mechanical stresses within the diaphragm is described. These calculations have lead to an optimized placement of the piezoresistors in order to achieve a maximum sensitivity. The result of this work is a sensor which has well known properties. Important parameters including sensitivity, resonance frequency and maximum load are described precisely. These are necessary to enable new measurements in the boundary layer of fluids. The experiments and the initial results, e.g. its linearity and its dynamic capability are demonstrated in several figures.

  16. Melange rheology, fluid pressure distribution, and seismic style (Invited)

    Science.gov (United States)

    Fagereng, A.; Sibson, R. H.

    2010-12-01

    Subduction megathrusts accommodate shear displacements in a range of seismic styles, including standard earthquakes, non-volcanic tremor, and continuous and transitory aseismic slip. Subduction channel shear zones, containing highly sheared, fluid-saturated trench-fill sediments intermingled with fragments of oceanic crust, are commonly inferred to occur along active subduction thrust interfaces. If this interpretation is correct, these plate boundary faults are not discrete planes, but may resemble the mélange shear zones commonly found in exhumed subduction-related rock assemblages. In such shear zones, deformation is accommodated by a mixture of continuous matrix flow and localized slip on numerous shear discontinuities. The dominant deformation mode in a mélange appears to depend critically on the ratio of competent to incompetent material, with shear discontinuities localized along lithological contacts or within competent domains, while matrix flow accommodates shearing by distributed strain. If the style of strain/displacement accommodation in a mélange reflects the partitioning between aseismic and seismic slip, the proportion of competent material seems likely to be a significant factor affecting seismic style within subduction channel shear zones. Along the Hikurangi margin, New Zealand, interseismic coupling varies from strong in the south to weak in the north. Variations in accretionary prism geometry indicate that the megathrust is mechanically stronger in the weakly coupled segment, than in the strongly coupled region. Thus, along this megathrust, weak coupling appears to occur on a relatively strong fault segment, while strong coupling relates to weak segments of the plate boundary. This may be caused by a fluid pressure difference, where frictional sliding is preferred in the strongly coupled, mechanically weak segment, where the incoming plate is relatively smooth and the overlying plate inferred to be relatively impermeable. In the weakly

  17. Lack of relationship between resistance to cerebrospinal fluid outflow and intracranial pressure in normal pressure hydrocephalus.

    Science.gov (United States)

    Eide, P K; Fremming, A D; Sorteberg, A

    2003-12-01

    To explore whether calculation of resistance to cerebrospinal fluid (CSF) outflow (Rout) by the lumbar constant rate infusion test in a reliable way predicts the intracranial pressure (ICP) profile in normal pressure hydrocephalus (NPH). A prospective study was undertaken including 16 cases with clinical signs of normal pressure hydrocephalus that were investigated with both continuous ICP monitoring and the lumbar constant rate infusion test. Intracranial pressure monitoring was performed for about 24 h, and supplied with a simultaneous lumbar constant rate infusion test at the end of the monitoring period. The pressure recordings were analysed using the Sensometrics Pressure Analyser. Various characteristics of the pressure curves were compared. The continuous ICP recordings were considered as normal (mean ICP or =12.0 mmHg/ml/min) in 12 of 16 cases. There was no relationship between lumbar Rout and mean ICP during sleep. We could not find any relationship between lumbar Rout and number of nightly ICP elevations of 1525 mmHg lasting 0.5 or 1 min. Neither resistance to CSF outflow (Rout) nor mean ICP during sleep was related to the ventricular size. The results of this prospective study revealed no significant relationship between resistance to CSF outflow (Rout) and the ICP profile in NPH cases. The results also suggest that caution should be made when predicting the ICP profile on the basis of measuring the lumbar CSF pressure for a few minutes duration.

  18. Thermal Hydraulic Analysis of a Passive Residual Heat Removal System for an Integral Pressurized Water Reactor

    Directory of Open Access Journals (Sweden)

    Junli Gou

    2009-01-01

    Full Text Available A theoretical investigation on the thermal hydraulic characteristics of a new type of passive residual heat removal system (PRHRS, which is connected to the reactor coolant system via the secondary side of the steam generator, for an integral pressurized water reactor is presented in this paper. Three-interknited natural circulation loops are adopted by this PRHRS to remove the residual heat of the reactor core after a reactor trip. Based on the one-dimensional model and a simulation code (SCPRHRS, the transient behaviors of the PRHRS as well as the effects of the height difference between the steam generator and the heat exchanger and the heat transfer area of the heat exchanger are studied in detail. Through the calculation analysis, it is found that the calculated parameter variation trends are reasonable. The higher height difference between the steam generator and the residual heat exchanger and the larger heat transfer area of the residual heat exchanger are favorable to the passive residual heat removal system.

  19. Numerical design and optimization of hydraulic resistance and wall shear stress inside pressure-driven microfluidic networks.

    Science.gov (United States)

    Damiri, Hazem Salim; Bardaweel, Hamzeh Khalid

    2015-11-07

    Microfluidic networks represent the milestone of microfluidic devices. Recent advancements in microfluidic technologies mandate complex designs where both hydraulic resistance and pressure drop across the microfluidic network are minimized, while wall shear stress is precisely mapped throughout the network. In this work, a combination of theoretical and modeling techniques is used to construct a microfluidic network that operates under minimum hydraulic resistance and minimum pressure drop while constraining wall shear stress throughout the network. The results show that in order to minimize the hydraulic resistance and pressure drop throughout the network while maintaining constant wall shear stress throughout the network, geometric and shape conditions related to the compactness and aspect ratio of the parent and daughter branches must be followed. Also, results suggest that while a "local" minimum hydraulic resistance can be achieved for a geometry with an arbitrary aspect ratio, a "global" minimum hydraulic resistance occurs only when the aspect ratio of that geometry is set to unity. Thus, it is concluded that square and equilateral triangular cross-sectional area microfluidic networks have the least resistance compared to all rectangular and isosceles triangular cross-sectional microfluidic networks, respectively. Precise control over wall shear stress through the bifurcations of the microfluidic network is demonstrated in this work. Three multi-generation microfluidic network designs are considered. In these three designs, wall shear stress in the microfluidic network is successfully kept constant, increased in the daughter-branch direction, or decreased in the daughter-branch direction, respectively. For the multi-generation microfluidic network with constant wall shear stress, the design guidelines presented in this work result in identical profiles of wall shear stresses not only within a single generation but also through all the generations of the

  20. 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.

  1. 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;

  2. Vertical hydraulic conductivity of a clayey-silt aquitard: accelerated fluid flow in a centrifuge permeameter compared with in situ conditions

    Directory of Open Access Journals (Sweden)

    W. A. Timms

    2014-03-01

    Full Text Available Evaluating the possibility of leakage through low permeability geological strata is critically important for sustainable water supplies, extraction of fuels from strata such as coal beds, and confinement of waste within the earth. Characterizing low or negligible flow rates and transport of solutes can require impractically long periods of field or laboratory testing, but is necessary for evaluations over regional areas and over multi-decadal timescales. The current work reports a custom designed centrifuge permeameter (CP system, which can provide relatively rapid and reliable hydraulic conductivity (K measurement compared to column permeameter tests at standard gravity (1g. Linear fluid velocity through a low K porous sample is linearly related to g-level during a CP flight unless consolidation or geochemical reactions occur. The CP module is designed to fit within a standard 2 m diameter, geotechnical centrifuge with a capacity for sample dimensions of 30 to 100 mm diameter and 30 to 200 mm in length. At maximum RPM the resultant centrifugal force is equivalent to 550g at base of sample or a total stress of ~2 MPa. K is calculated by measuring influent and effluent volumes. A custom designed mounting system allows minimal disturbance of drill core samples and a centrifugal force that represents realistic in situ stress conditions is applied. Formation fluids were used as influent to limit any shrink-swell phenomena which may alter the resultant K value. Vertical hydraulic conductivity (Kv results from CP testing of core from the sites in the same clayey silt formation varied (10−7 to 10−9 m s−1, n = 14 but higher than 1g column permeameter tests of adjacent core using deionized water (10−9 to 10−11 m s−1, n = 7. Results at one site were similar to in situ Kv values (3 × 10−9 m s−1 from pore pressure responses within a 30 m clayey sequence in a homogenous area of the formation. Kv sensitivity to sample heterogeneity was

  3. Intracranial pressure and cerebrospinal fluid outflow conductance in healthy subjects.

    Science.gov (United States)

    Albeck, M J; Børgesen, S E; Gjerris, F; Schmidt, J F; Sørensen, P S

    1991-04-01

    Conductance of cerebrospinal fluid (CSF) outflow (Cout) is an important parameter to be considered in patients with CSF circulation abnormalities. In patients with normal-pressure hydrocephalus it is the single most important parameter in determining if the patient needs CSF shunting. The lower normal limit for Cout has been estimated from the effect of shunting in patients with normal-pressure hydrocephalus, from patients retrospectively reevaluated after recovering from illness, and from patients with known abnormalities in the brain or the CSF system. The true value of Cout in normal individuals, however, has hitherto not been reported. In the present study, Cout has been measured by a lumbar infusion test in eight young volunteers with no suspicion of disease. The mean intracranial pressure (ICP) was 11 mm Hg and a linear relationship was found between CSF absorption and ICP. The mean Cout was 0.11 ml/min/mm Hg and the lower 95% confidence level was 0.10 ml/min/mm Hg. These values are in accordance with those obtained from previous studies.

  4. A batch fabricated capacitive pressure sensor with an integrated Guyton capsule for interstitial fluid pressure measurement

    Science.gov (United States)

    Maleki, Teimour; Fogle, Benjamin; Ziaie, Babak

    2011-05-01

    In this paper, we present the design, fabrication and test of a batch fabricated capacitive pressure sensor with an integrated Guyton capsule for interstitial fluid pressure measurement. The sensor is composed of 12 µm thick single crystalline silicon membrane and a 3 µm gap, hermetically sealed through silicon-glass anodic bonding. A novel batch scale method for creating electrical feed-throughs inside the sealed capacitor chamber is developed. The Guyton capsule consists of an array of 10 µm diameter access holes etched onto a silicon back-plate separated from the silicon sensing membrane by a gap of 5 µm. The presence of the Guyton capsule (i.e. plates with access holes plus the gap separating them from the sensing membrane) allows for the ingress of interstitial fluid inside the 5 µm gap following the implantation, thus, providing an accurate measurement of interstitial fluid pressure. The fabricated sensor is 3 × 2 × 0.42 mm3 in dimensions and has a maximum sensitivity of 10 fF mmHg-1.

  5. Design of a laboratory hydraulic device for testing of hydraulic pumps

    Directory of Open Access Journals (Sweden)

    Pavel Máchal

    2013-01-01

    Full Text Available The present contribution deals with solves problem of research of testing device to monitor of hydrostatic pumps durability about dynamic loading under laboratory conditions. When carrying out the design of testing device are based on load characteristics of tractor hydraulic circuit, the individual characteristics of hydraulic components and performed calculations. Load characteristics on the tractors CASE IH Magnum 310, JOHN DEERE 8100, ZETOR FORTERRA 114 41 and Fendt 926 Vario were measured. Design of a hydraulic laboratory device is based on the need for testing new types of hydraulic pumps or various types of hydraulic fluids. When creating of hydraulic device we focused on testing hydraulic pumps used in agricultural and forestry tractors. Proportional pressure control valve is an active member of the hydraulic device, which provides change of a continuous control signal into relative pressure of operating fluid. The advantage of a designed hydraulic system is possibility of simulation of dynamic operating loading, which is obtained by measurement under real conditions, and thereby creates laboratory conditions as close to real conditions as possible. The laboratory device is constructed at the Department of Transport and Handling, Faculty of Engineering, Slovak University of Agriculture in Nitra.

  6. Stimuli-Responsive/Rheoreversible Hydraulic Fracturing Fluids as a Greener Alternative to Support Geothermal and Fossil Energy Production

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hun Bok; Carroll, KC; Kabilan, Senthil; Heldebrant, David J.; Hoyt, David W.; Zhong, Lirong; Varga, Tamas; Stephens, Sean A.; Adams, Lexor; Bonneville, Alain; Kuprat, Andrew P.; Fernandez, Carlos A.

    2015-01-01

    Cost-effective yet safe creation of high-permeability reservoirs within deep bedrock is the primary challenge for the viability of enhanced geothermal systems (EGS) and unconventional oil/gas recovery. Although fracturing fluids are commonly used for oil/gas, standard fracturing methods are not developed or proven for EGS temperatures and pressures. Furthermore, the environmental impacts of currently used fracturing methods are only recently being determined. Widespread concerns about the environmental contamination have resulted in a number of regulations for fracturing fluids advocating for greener fracturing processes. To enable EGS feasibility and lessen environmental impact of reservoir stimulation, an environmentally benign, CO2-activated, rheoreversible fracturing fluid that enhances permeability through fracturing (at significantly lower effective stress than standard fracturing fluids) due to in situ volume expansion and gel formation is investigated herein. The chemical mechanism, stability, phase-change behavior, and rheology for a novel polyallylamine (PAA)-CO2 fracturing fluid was characterized at EGS temperatures and pressures. Hydrogel is formed upon reaction with CO2 and this process is reversible (via CO2 depressurization or solubilizing with a mild acid) allowing removal from the formation and recycling, decreasing environmental impact. Rock obtained from the Coso geothermal field was fractured in laboratory experiments under various EGS temperatures and pressures with comparison to standard fracturing fluids, and the fractures were characterized with imaging, permeability measurement, and flow modeling. This novel fracturing fluid and process may vastly reduce water usage and the environmental impact of fracturing practices and effectively make EGS production and unconventional oil/gas exploitation cost-effective and cleaner.

  7. Pancreatic tissue fluid pressure in chronic pancreatitis. Relation to pain, morphology, and function

    DEFF Research Database (Denmark)

    Ebbehøj, N; Borly, L; Bülow, J

    1990-01-01

    The relation between pancreatic tissue fluid pressure and pain, morphology, and function was studied in a cross-sectional investigation. Pressure measurements were performed by percutaneous fine-needle puncture. Thirty-nine patients with chronic pancreatitis were included, 25 with pain and 14...... calcifications. In conclusion, pancreatic tissue fluid pressure is a valuable indicator of pain in chronic pancreatitis....

  8. Novel wave power analysis linking pressure-flow waves, wave potential, and the forward and backward components of hydraulic power.

    Science.gov (United States)

    Mynard, Jonathan P; Smolich, Joseph J

    2016-04-15

    Wave intensity analysis provides detailed insights into factors influencing hemodynamics. However, wave intensity is not a conserved quantity, so it is sensitive to diameter variations and is not distributed among branches of a junction. Moreover, the fundamental relation between waves and hydraulic power is unclear. We, therefore, propose an alternative to wave intensity called "wave power," calculated via incremental changes in pressure and flow (dPdQ) and a novel time-domain separation of hydraulic pressure power and kinetic power into forward and backward wave-related components (ΠP±and ΠQ±). Wave power has several useful properties:1) it is obtained directly from flow measurements, without requiring further calculation of velocity;2) it is a quasi-conserved quantity that may be used to study the relative distribution of waves at junctions; and3) it has the units of power (Watts). We also uncover a simple relationship between wave power and changes in ΠP±and show that wave reflection reduces transmitted power. Absolute values of ΠP±represent wave potential, a recently introduced concept that unifies steady and pulsatile aspects of hemodynamics. We show that wave potential represents the hydraulic energy potential stored in a compliant pressurized vessel, with spatial gradients producing waves that transfer this energy. These techniques and principles are verified numerically and also experimentally with pressure/flow measurements in all branches of a central bifurcation in sheep, under a wide range of hemodynamic conditions. The proposed "wave power analysis," encompassing wave power, wave potential, and wave separation of hydraulic power provides a potent time-domain approach for analyzing hemodynamics.

  9. 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.

  10. PFLOW: A 3-D Numerical Modeling Tool for Calculating Fluid-Pressure Diffusion from Coulomb Strain

    Science.gov (United States)

    Wolf, L. W.; Lee, M.; Meir, A.; Dyer, G.; Ma, K.; Chan, C.

    2009-12-01

    A new 3D time-dependent pore-pressure diffusion model PFLOW is developed to investigate the response of pore fluids to the crustal deformation generated by strong earthquakes in heterogeneous geologic media. Given crustal strain generated by changes in Coulomb stress, this MATLAB-based code uses Skempton's coefficient to calculate resulting changes fluid pressure. Pore-pressure diffusion can be tracked over time in a user-defined model space with user-prescribed Neumann or Dirchilet boundary conditions and with spatially variable values of permeability. PFLOW employs linear or quadratic finite elements for spatial discretization and first order or second order, explicit or implicit finite difference discretization in time. PFLOW is easily interfaced with output from deformation modeling programs such as Coulomb (Toda et al., 2007) or 3D-DEF (Gomberg and Ellis, 1994). The code is useful for investigating to first-order the evolution of pore pressure changes induced by changes in Coulomb stress and their possible relation to water-level changes in wells or changes in stream discharge. It can also be used for student research and classroom instruction. As an example application, we calculate the coseismic pore pressure changes and diffusion induced by volumetric strain associated with the 1999 Chi-Chi earthquake (Mw = 7.6) in Taiwan. The Chi-Chi earthquake provides an unique opportunity to investigate the spatial and time-dependent poroelastic response of near-field rocks and sediments because there exist extensive observational data of water-level changes and crustal deformation. The integrated model allows us to explore whether changes in Coulomb stress can adequately explain hydrologic anomalies observed in areas such as Taiwan’s western foothills and the Choshui River alluvial plain. To calculate coseismic strain, we use the carefully calibrated finite fault-rupture model of Ma et al. (2005) and the deformation modeling code Coulomb 3.1 (Toda et al., 2007

  11. Wear forms of heterogeneous electro-rheological fluids working in a hydraulic clutch system

    Science.gov (United States)

    Ziabska, E.; Duchowski, J.; Olszak, A.; Osowski, K.; Kesy, A.; Kesy, Z.; Choi, S. B.

    2017-09-01

    The paper presents experimental results concerning the wear of heterogeneous electro-rheological (ER) fluids operating as working fluids in a complex clutch system consisting of a hydrodynamic clutch and a cylinder viscous clutch. The change of electric field intensity in the clutches results in change of sheer stress values in working fluids what causes the change of transmitted torque. This work shows that the most important factors affecting the wear of the ER fluid are the electric field of high intensity, the accompanying electrical breakdown, and the high temperature of the silicone oil. In addition, the water from the humid air absorbed mainly by hygroscopic particles influences a significant impact on the wear of the working fluid. Various forms of wear particles of the fluid depending on the prevailing conditions such as working mode are observed from the microscopic aspects. It is observed that the particles are flattened, rolled out or smashed into smaller fragments, partially melted, wrinkled and glued or caked. In addition, it is identified that the partial destruction of silicone oil is occurred due to the damage of the hydrocarbon chains, as evidenced by the decrease in its viscosity and the presence of the particle matter newly containing silicon.

  12. 液压冲击器氮气室预充压力对冲击性能的影响研究%Influence of Precharge Pressure of Nitrogen Chamber on Hydraulic Impactor's Performance

    Institute of Scientific and Technical Information of China (English)

    梁翠平; 杨国平; 王亮; 丁冲冲

    2011-01-01

    Based on analyzing the working principle and characteristics of hydraulic impactor, the nonlinear mathematical model of a hydraulic impactor system was established. By using MATLAB/ Simulink, the simulation of two processes including the accelerated return stroke and travel stroke of the hydraulic impactor were researched, and the influence of precharge pressure of nitrogen chamber on the percussion performance was analyzed. The results show that: if the precharge pressure of nitrogen chamber is too Large , it will result in hydraulic fluid can not move the piston to return, and hydraulic impactor can not start up; if the pressure is too small, it will induce difficulty to raise the impacting pressure, and the impacting energy will be small.%在分析液压冲击器工作原理及特点的基础上,建立液压冲击器系统的非线性数学模型.运用MATLAB/Simulink 分别对液压冲击器的回程加速过程和冲程过程进行仿真研究,分析氮气室预充压力对冲击器冲击性能的影响程度.结果表明:氮气室预充压力过大,会导致液压油不能推动活塞进行回程,液压冲击器起动不了;压力过小,则很容易使冲击压力升不上去,冲击能小.

  13. Based on PLC and FluidSIM Software of Hydraulic and Pneumatic Transmission Teaching Design%基于PLC和Flui dSIM软件的液压传动控制的设计

    Institute of Scientific and Technical Information of China (English)

    李生山

    2014-01-01

    FluidSIM software intuitive user interface .A similar drawing graphical operation interface ,drag the icon design ,object-oriented set parameters ,easy to learn ,users can quickly learn to draw electrical-hydraulic (pneumatic) circuit diagram ,and carries on the simulation .CX-Programmer is a very easy to create of Omron PLC ,to monitor the software and online editor ,in the hydrau-lic pressure drive control system with PLC for the hydraulic cylinder to achieve freedom and movement ,in order to realize feed movement of power sliding table .%FluidSIM 软件可把图库中的元件直接拖到制图区生成该元件的原理图,并对接口间回路链接,即可生成所需的回路界面,通过改变对象参数,对其进行仿真,便于查错和绘制电液压(气压)回路图。CX-Programmer是一款很容易对Omron PLC进行创建、监控和在线编辑程序的软件,在液压传动控制系统中通过PLC让液压缸实现进退动作,以便实现滑台的进给和回退运动。

  14. Intraocular pressure and estimated cerebrospinal fluid pressure. The Beijing Eye Study 2011.

    Science.gov (United States)

    Wang, Ya Xing; Jonas, Jost B; Wang, Ningli; You, Qi Sheng; Yang, Diya; Xie, Xiao Bin; Xu, Liang

    2014-01-01

    To examine a potential association between intraocular pressure (IOP) and cerebrospinal fluid pressure (CSFP) in a population-based setting. The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range: 50-93 years). A detailed ophthalmic examination was performed. Based on a previous study with lumbar cerebrospinal fluid pressure (CSFP) measurements, CSFP was calculated as CSFP [mm Hg] = 0.44×Body Mass Index [kg/m2]+0.16×Diastolic Blood Pressure [mm Hg]-0.18×Age [Years]. In multivariate analysis, IOP was associated with higher estimated CSFP (Pregion of habitation (P<0.001; beta:-0.37; B:-2.78;95%CI:-3.07,-2.48), higher systolic blood pressure (P<0.001; beta: 0.34; B: 0.06;95%CI: 0.05,0.07), higher pulse rate (P = 0.003; beta: 0.05; B: 0.02;95%CI: 0.01,0.03), taller body height (P<0.001; beta: 0.11; B: 0.05;95%CI: 0.03,0.07), higher blood concentration of cholesterol (P = 0.003; beta: 0.05; B: 0.17;95%CI: 0.06,0.28) and higher level of education (P = 0.003; beta: 0.09; B: 0.30;95%CI: 0.16,0.45). IOP was positively associated with estimated CSFP after adjusting for other ocular and systemic parameters. As a corollary, higher estimated CSFP was significantly associated with higher IOP in multivariate analysis. It fits with the notion that the arterial blood pressure, estimated CSFP and IOP are physiologically correlated with each other.

  15. 一种用于液体静压导轨的高精密液压站设计%Design of the Ultra-precision Hydraulic Station for Hydraulic Static Pressured Guide

    Institute of Scientific and Technical Information of China (English)

    赵午云; 郭勇

    2014-01-01

    Hydraulic static pressured guide is the important function unit of precision machine tool. Hydraulic station is indispen-sable and supplementary unit for hydraulic static pressured guide in normal operation,and must provide hydraulic static pressured guide with lubricating oil of invariable pressure. An ultra-precision hydraulic station for hydraulic static pressured guide was designed. In this hydraulic station,lubricating oil was provided by precision gear pump driven by variable frequency motor,and pressure export was ensured to be steady by full-closed loop feedback control. The export pressure precision of the hydraulic station can reach ± 0.05%. Good effect is gained in the application of the hydraulic station on the hydraulic static pressured guide of ultra-precision machine tool.%液体静压导轨是精密超精密加工机床的重要功能单元,液压站是液体静压导轨正常工作的必要辅助单元。液体静压导轨要保持高的精度,液压站必须能够为静压导轨提供压力非常稳定的润滑油输入。设计一种用于液体静压导轨的高精密液压站,该液压站利用变频电机驱动精密齿轮泵供给润滑油,利用全闭环反馈调节装置控制润滑油的稳压输出。实际测量证明:该液压站的输出压力稳定精度可达±0.05%,应用于超精密机床上的液体静压导轨取得了良好的效果。

  16. Intracranial pressure and conductance to outflow of cerebrospinal fluid in normal-pressure hydrocephalus.

    Science.gov (United States)

    Børgesen, S E; Gjerris, F; Sørensen, S C

    1979-04-01

    Forty patients with clinical evidence of normal-pressure hydrocephalus were studied by monitoring intraventricular pressure during a 24-hour period, and by a lumboventricular perfusion test for measurement of the conductance to outflow of cerebrospinal fluid (CSF). The purpose of the study was to investigate whether there is a relationship between intraventricular pressure and conductance to outflow of CSF, and whether it is possible to use the results from pressure monitoring in the selection of patients who may be expected to benefit from shunting therapy. The conductance to outflow was used as an evaluation factor in the selection of patients to be treated by a shunt. The conductance to CSF outflow differed by twelvefold between the lowest and highest values. The level of resting intraventricular pressure was within normal limits in all patients. Accordingly, there was no evidence of a relationship between conductance to outflow and intraventricular pressure. So-called B-waves were seen more frequently in patients with decreased conductance to outflow, but were also present in patients with high conductance to outflow. Therefore, the presence of B-waves does not imply a low conductance to outflow of CSF.

  17. 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.

  18. Elevated cerebrospinal fluid pressure in patients with Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Fellmann Jere

    2006-05-01

    Full Text Available Abstract Background Abnormalities in cerebrospinal fluid (CSF production and turnover, seen in normal pressure hydrocephalus (NPH and in Alzheimer's disease (AD, may be an important cause of amyloid retention in the brain and may relate the two diseases. There is a high incidence of AD pathology in patients being shunted for NPH, the AD-NPH syndrome. We now report elevated CSF pressure (CSFP, consistent with very early hydrocephalus, in a subset of AD patients enrolled in a clinical trial of chronic low-flow CSF drainage. Our objective was to determine the frequency of elevated CSFP in subjects meeting National Institutes of Neurological and Communicative Diseases and Stroke – Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA criteria for AD, excluding those with signs of concomitant NPH. Methods AD subjects by NINCDS-ADRDA criteria (n = 222, were screened by history, neurological examination, and radiographic imaging to exclude those with clinical or radiographic signs of NPH. As part of this exclusion process, opening CSFP was measured supine under general anesthesia during device implantation surgery at a controlled pCO2 of 40 Torr (40 mmHg. Results Of the 222 AD subjects 181 had pressure measurements recorded. Seven subjects (3.9% enrolled in the study had CSFP of 220 mmH20 or greater, mean 249 ± 20 mmH20 which was significantly higher than 103 ± 47 mmH2O for the AD-only group. AD-NPH patients were significantly younger and significantly less demented on the Mattis Dementia Rating Scale (MDRS. Conclusion Of the AD subjects who were carefully screened to exclude those with clinical NPH, 4% had elevated CSFP. These subjects were presumed to have the AD-NPH syndrome and were withdrawn from the remainder of the study.

  19. Characterization of Hydraulic Fracture with Inflated Dislocation Moving Within a Semi-infinite Medium

    Institute of Scientific and Technical Information of China (English)

    OUYANG Zhi-hua; ELSWORTH Derek; LI Qiang

    2007-01-01

    Hydraulic fracturing is accompanied by a change in pore fluid pressure. As a result, this may be conveniently represented as inflated dislocation moving within a semi-infinite medium. Theory is developed to describe the pore pressures that build up around an inflated volumetric dislocation migrating within a saturated porous-elastic semi-infinite medium as analog to hydraulic fracturing emplacement. The solution is capable of evaluating the system behavior of both constant fluid pressure and zero flux surface conditions through application of a superposition. Characterization of horizontal moving dislocation processes is conducted as an application of these techniques. Where the mechanical and hydraulic parameters are defined, a priori, type curve matching of responses may be used to evaluate emplacement location uniquely. Pore pressure response elicited at a dilation, subject to pressure control is of interest in representing hydraulic fracturing where leak-off is an important component. The effect of hydraulic fracturing on fracture fluid pressure is evaluated in a poroelastic hydraulic fracture model utilizing dislocation theory. A minimum set of dimensionless parameters are defined that describe the system. Pore fluid pressures recorded during hydraulic fracturing of a well in the San Joaquin Valley of Central California is examined using the proposed model. The estimated geometry of the hydraulic fracture is matched with reasonable fidelity with the measured data.

  20. Extensive use of computational fluid dynamics in the upgrading of hydraulic turbines

    Energy Technology Data Exchange (ETDEWEB)

    Sabourin, M.; De Henau, V. [GEC Alsthom Electromechanical Inc., Tracy, PQ (Canada); Eremeef, R. [GEC Alsthom Neyrpic, Grenoble (France)

    1995-12-31

    The use of computational fluid flow dynamics (CFD) and the Navier Stokes equations by GEC Alsthom for turbine rehabilitation were discussed. The process of runner rehabilitation was discussed from a fluid flow perspective, which accounts for the spiral case-distributor set and draft tube. The Kootenay turbine rehabilitation was described with regard to it spiral case and stay vane. The numerical analysis used to model upstream components was explained. The influence of draft tube effects was emphasized as an important efficiency factor. The differences between draft tubes at Sir Adam Beck 2 and La Grande 2 were discussed. Computational fluid flow modelling was claimed to have produced global performance enhancements in a reasonably short time, and at a reasonable cost. 6 refs., 6 figs., 4 tabs.

  1. ADSORPTION OF HARD SPHERE FLUID IN POROUS MATERIAL: A MONTE CARLO SIMULATION APPROACH FOR PRESSURE CALCULATION

    Directory of Open Access Journals (Sweden)

    P.Orea

    2003-01-01

    Full Text Available We have performed Monte Carlo simulations in the canonical ensemble of a hard-sphere fluid adsorbed in microporous media. The pressure of the adsorbed fluid is calculated by using an original procedure that includes the calculations of the pressure tensor components during the simulation. In order to confirm the equivalence of bulk and adsorbed fluid pressures, we have exploited the mechanical condition of equilibrium and performed additional canonical Monte Carlo simulations in a super system "bulk fluid + adsorbed fluid". When the configuration of a model porous media permits each of its particles to be in contact with adsorbed fluid particles, we found that these pressures are equal. Unlike the grand canonical Monte Carlo method, the proposed calculation approach can be used efficiently to obtain adsorption isotherms over a wide range of fluid densities and porosities of adsorbent.

  2. Computational Fluid Dynamics Modelling of Hydraulics and Sedimentation in Process Reactors during Aeration Tank Settling

    DEFF Research Database (Denmark)

    Jensen, M.D.; Ingildsen, P.; Rasmussen, Michael R.;

    2006-01-01

    Aeration tank settling is a control method allowing settling in the process tank during highhydraulic load. The control method is patented. Aeration tank settling has been applied in several wastewater treatment plants using the present design of the process tanks. Some process tank designs...... haveshown to be more effective than others. To improve the design of less effective plants, computational fluiddynamics (CFD) modelling of hydraulics and sedimentation has been applied. This paper discusses theresults at one particular plant experiencing problems with partly short-circuiting of the inlet...... and outletcausing a disruption of the sludge blanket at the outlet and thereby reducing the retention of sludge in theprocess tank. The model has allowed us to establish a clear picture of the problems arising at the plantduring aeration tank settling. Secondly, several process tank design changes have been...

  3. Fluid pressurization and tractional forces during TMJ disc loading: A biphasic finite element analysis.

    Science.gov (United States)

    Wu, Y; Cisewski, S E; Wei, F; She, X; Gonzales, T S; Iwasaki, L R; Nickel, J C; Yao, H

    2017-06-01

    To investigate the ploughing mechanism associated with tractional force formation on the temporomandibular joint (TMJ) disc surface. Ten left TMJ discs were harvested from 6- to 8-month-old male Yorkshire pigs. Confined compression tests characterized mechanical TMJ disc properties, which were incorporated into a biphasic finite element model (FEM). The FEM was established to investigate load carriage within the extracellular matrix (ECM) and the ploughing mechanism during tractional force formation by simulating previous in vitro plough experiments. Biphasic mechanical properties were determined in five TMJ disc regions (average±standard deviation for aggregate modulus: 0.077±0.040 MPa; hydraulic permeability: 0.88±0.37×10(-3) mm(4) /Ns). FE simulation results demonstrated that interstitial fluid pressurization is a dominant loading support mechanism in the TMJ disc. Increased contact load and duration led to increased solid ECM strain and stress within, and increased ploughing force on the surface of the disc. Sustained mechanical loading may play a role in load carriage within the ECM and ploughing force formation during stress-field translation at the condyle-disc interface. This study further elucidated the mechanism of ploughing on tractional force formation and provided a baseline for future analysis of TMJ mechanics, cartilage fatigue and early TMJ degeneration. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Evaluation of pancreatic tissue fluid pressure and pain in chronic pancreatitis. A longitudinal study

    DEFF Research Database (Denmark)

    Ebbehøj, N; Borly, L; Bülow, J

    1990-01-01

    Pancreatic tissue fluid pressure and pain were compared in a longitudinal study in nine patients undergoing drainage operations for pain in chronic pancreatitis. Pressure measurements were performed percutaneously before the operation, intraoperatively before and after the drainage procedure....... The duration of the pain-free period was significantly related to the size of the intraoperative pressure decrease (R = 0.79, p less than 0.03). These results further suggest that there is a causal relationship between pancreatic tissue fluid pressure and pain in chronic pancreatitis and that the success...... of the drainage procedure may be predicted by intraoperative pancreatic tissue fluid pressure measurements....

  5. Pressure development due to viscous fluid flow through a converging gap

    OpenAIRE

    Imhamed, Ahmed

    2004-01-01

    The behaviour of fluid flow in industrial processes is essential for numerous applications and there have been vast amount of work on the hydrodynamic pressure generated due to the flow of viscous fluid. One major manifestation of hydrodynamic pressure application is the wire coating/drawing process, where the wire is pulled through a unit either conical or cylindrical bore filled with a polymer melt that gives rise to the hydrodynamic pressure inside the unit. The hydrodynamic pressure distr...

  6. COHESIVE ZONE FINITE ELEMENT-BASED MODELING OF HYDRAULIC FRACTURES

    Institute of Scientific and Technical Information of China (English)

    Zuorong Chen; A.P. Bunger; Xi Zhang; Robert G. Jeffrey

    2009-01-01

    Hydraulic fracturing is a powerful technology used to stimulate fluid production from reservoirs. The fully 3-D numerical simulation of the hydraulic fracturing process is of great importance to the efficient application of this technology, but is also a great challenge because of the strong nonlinear coupling between the viscous flow of fluid and fracture propagation. By taking advantage of a cohesive zone method to simulate the fracture process, a finite element model based on the existing pore pressure cohesive finite elements has been established to investigate the propagation of a penny-shaped hydraulic fracture in an infinite elastic medium. The effect of cohesive material parameters and fluid viscosity on the hydraulic fracture behaviour has been investigated. Excellent agreement between the finite element results and analytical solutions for the limiting case where the fracture process is dominated by rock fracture toughness demonstrates the ability of the cohesive zone finite element model in simulating the hydraulic fracture growth for this case.

  7. 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.

  8. Final report of supplementary comparison SIM.M.P-S7: Hydraulic pressure comparison from 7 MPa to 70 MPa

    Science.gov (United States)

    Gil Romero, Juan Carlos; Catalina Neira, María; Torres Guzmán, Jorge C.

    2013-01-01

    This report presents the final results of supplementary comparison SIM.M.P-S7 in the field of hydraulic pressure up to 70 MPa, within the PTB-ANDIMET-PLUS project. Seven national pressure reference laboratories participated in this comparison, which started with an opening meeting in November 2011 at the city of Lima; the closing meeting was held at the National Metrology Institute of Colombia INM, at Bogota, on 27-28 November 2012. Each participating laboratory used for the comparison its best hydraulic pressure balance standard in the range from 7 MPa to 70 MPa. The transfer standard for the comparison was a digital manometer DH Instruments Fluke RPM-4 with an accuracy of 0.008% of the reading. The reference laboratory and advisor for the comparison was CENAM, Mexico. The comparison protocol and results analysis was made by the pressure laboratory of National Metrology Institute INM (Colombia) who participated in the comparison as well. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by SIM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  9. Transputers in Fluid Power - Design and Applications. Chapter 5 in Advances in Hydraulic Control Systems

    DEFF Research Database (Denmark)

    Conrad, Finn

    Deals with results and trends on mechatronics in fluid power and intelligent control of machines and robots. New results are presented concerning transputer-basen distributed control of machines and robots. Experimental results with the DTU mechatronic test facility are presented and discussed. S....... Several adaptive control algoritms are investigated and evaluated. Promissing results are obtained with Computed Valve-Input Control (CIC), Adaptive Model-based Actuator Control (AMAC) and Linear Pertubation Adaptive Control (LPAC).......Deals with results and trends on mechatronics in fluid power and intelligent control of machines and robots. New results are presented concerning transputer-basen distributed control of machines and robots. Experimental results with the DTU mechatronic test facility are presented and discussed...

  10. Evaluation of pancreatic tissue fluid pressure measurements intraoperatively and by sonographically guided fine-needle puncture

    DEFF Research Database (Denmark)

    Ebbehøj, N; Borly, L; Bülow, J;

    1990-01-01

    pressure measurements via direct puncture. Furthermore, no significant difference was seen between pancreatic duct and tissue fluid pressure. The technical evaluation was performed by repeated pressure measurements in human pancreatic autopsy specimens and living rats in a pressure chamber at various...... external pressure levels. The basic calibration of the method evaluated by means of this pressure chamber study showed sufficient precision and accuracy of the needle technique for clinical and investigative purposes. In conclusion, our results suggest that pancreatic tissue fluid pressure can be reliably......The aim of the present study was to evaluate the needle method for pancreatic tissue fluid pressure measurements. Clinical evaluation was performed in 24 patients with chronic pancreatitis, comparing repeated pressure measurements via sonographically guided fine-needle puncture and intraoperative...

  11. Cerebrospinal Fluid Biomarkers in Idiopathic Normal Pressure Hydrocephalus

    Directory of Open Access Journals (Sweden)

    Ville Leinonen

    2011-01-01

    Full Text Available The diagnosis of idiopathic normal pressure hydrocephalus (iNPH is still challenging. Alzheimer's disease (AD, along with vascular dementia, the most important differential diagnosis for iNPH, has several potential cerebrospinal fluid (CSF biomarkers which might help in the selection of patients for shunt treatment. The aim of this study was to compare a battery of CSF biomarkers including well-known AD-related proteins with CSF from patients with suspected iNPH collected from the external lumbar drainage test (ELD. A total of 35 patients with suspected iNPH patients were evaluated with ELD. CSF was collected in the beginning of the test, and the concentrations of total tau, ptau181, Aβ42, NFL, TNF-α, TGFβ1, and VEGF were analysed by ELISA. Twenty-six patients had a positive ELD result—that is, their gait symptoms improved; 9 patients had negative ELD. The levels of all analyzed CSF biomarkers were similar between the groups and none of them predicted the ELD result in these patients. Contrary to expectations lumbar CSF TNF-α concentration was low in iNPH patients.

  12. Role of interstitial fluid pressurization in TMJ lubrication.

    Science.gov (United States)

    Zimmerman, B K; Bonnevie, E D; Park, M; Zhou, Y; Wang, L; Burris, D L; Lu, X L

    2015-01-01

    In temporomandibular joints (TMJs), the disc and condylar cartilage function as load-bearing, shock-absorbing, and friction-reducing materials. The ultrastructure of the TMJ disc and cartilage is different from that of hyaline cartilage in other diarthrodial joints, and little is known about their lubrication mechanisms. In this study, we performed micro-tribometry testing on the TMJ disc and condylar cartilage to obtain their region- and direction-dependent friction properties. Frictional tests with a migrating contact area were performed on 8 adult porcine TMJs at 5 different regions (anterior, posterior, central, medial, and lateral) in 2 orthogonal directions (anterior-posterior and medial-lateral). Some significant regional differences were detected, and the lateral-medial direction showed higher friction than the anterior-posterior direction on both tissues. The mean friction coefficient of condylar cartilage against steel was 0.027, but the disc, at 0.074, displayed a significantly higher friction coefficient. The 2 tissues also exhibited different frictional dependencies on sliding speed and normal loading force. Whereas the friction of condylar cartilage decreased with increased sliding speed and was independent of the magnitude of normal force, friction of the disc showed no dependence on sliding speed but decreased as normal force increased. Further analysis of the Péclet number and frictional coefficients suggested that condylar cartilage relies on interstitial fluid pressurization to a greater extent than the corresponding contact area of the TMJ disc.

  13. Identifying chemicals of concern in hydraulic fracturing fluids used for oil production.

    Science.gov (United States)

    Stringfellow, William T; Camarillo, Mary Kay; Domen, Jeremy K; Sandelin, Whitney L; Varadharajan, Charuleka; Jordan, Preston D; Reagan, Matthew T; Cooley, Heather; Heberger, Matthew G; Birkholzer, Jens T

    2017-01-01

    Chemical additives used for hydraulic fracturing and matrix acidizing of oil reservoirs were reviewed and priority chemicals of concern needing further environmental risk assessment, treatment demonstration, or evaluation of occupational hazards were identified. We evaluated chemical additives used for well stimulation in California, the third largest oil producing state in the USA, by the mass and frequency of use, as well as toxicity. The most frequently used chemical additives in oil development were gelling agents, cross-linkers, breakers, clay control agents, iron and scale control agents, corrosion inhibitors, biocides, and various impurities and product stabilizers used as part of commercial mixtures. Hydrochloric and hydrofluoric acids, used for matrix acidizing and other purposes, were reported infrequently. A large number and mass of solvents and surface active agents were used, including quaternary ammonia compounds (QACs) and nonionic surfactants. Acute toxicity was evaluated and many chemicals with low hazard to mammals were identified as potentially hazardous to aquatic environments. Based on an analysis of quantities used, toxicity, and lack of adequate hazard evaluation, QACs, biocides, and corrosion inhibitors were identified as priority chemicals of concern that deserve further investigation.

  14. Some effects of stress, friction and fluid flow on hydraulic fracturing

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, M.E.; Anderson, G.D.; Shaffer, R.J.; Thorson, L.D.

    1981-03-01

    We are conducting a DOE funded research program which is aimed at understanding the hydraulic fracturing process, especially those phenomena and parameters which strongly affect or control the fracture geometry. Our theoretical and experimental studies consistently confirm the well known fact that in-situ stress has a primary effect on fracture geometry and that fractures propagate perpendicular to the least principal stress. In addition, we find that frictional interfaces in reservoirs can affect fracturing. We have also quantified some of the effects on fracture geometry due to frictional slippage along interfaces. We found that variation of friction along an interface can result in abrupt steps in the fracture path. These effects have been seen in the mine back of emplaced fractures and are demonstrated both theoretically and in the laboratory. Further experiments and calculations are starting to indicate the possible control of the fracture height by the vertical change in the cables to X-608A wells should be replaced, and develop v across categories of persons affected. Respondents were selected according to a purposive sampling strategy, wn are also included. The management plan for the operation of the plant is discussed. (DMC)

  15. SITMILARITY LAW FOR HYDRAULIC DISTORTED MODEL

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Newton's general similarity criterion was applied to the distorted model. The results for the similarities of gravity force, drag force and pressure force are identical with those derived from relevant differential equations of fluid flow. And the selected limits of the distorted ratio were studied and the simulation of roughness coefficient of distorted model was conducted by means of hydraulic test.

  16. Towards improved estimation of the unsaturated soil hydraulic conductivity in the near saturated range by a fully automated, pressure controlled unit gradient experiment.

    Science.gov (United States)

    Werisch, Stefan; Müller, Marius

    2017-04-01

    Determination of soil hydraulic properties has always been an important part of soil physical research and model applications. While several experiments are available to measure the water retention of soil samples, the determination of the unsaturated hydraulic conductivity is often more complicated, bound to strong assumption and time consuming. Although, the application of unit gradient experiments is recommended since the middle of the last century, as one method towards a (assumption free) direct measurement of the unsaturated hydraulic conductivity, data from unit gradient experiments is seldom to never reported in literature. We developed and build a fully automated, pressure controlled, unit gradient experiment, which allows a precise determination of the unsaturated soil hydraulic conductivity K(h) and water retention VWC(h), especially in the highly dynamic near saturated range. The measurement apparatus applies the concept of hanging water columns and imposes the required soil water pressure by dual porous plates. This concepts allows the simultaneous and direct measurement of water retention and hydraulic conductivity. Moreover, this approach results in a technically less demanding experiment than related flux controlled experiments, and virtually any flux can be measured. Thus, both soil properties can be measured in mm resolution, for wetting and drying processes, between saturation and field capacity for all soil types. Our results show, that it is important to establish separate measurements of the unsaturated hydraulic conductivity in the near saturated range, as the shape of the retention function and hydraulic conductivity curve do not necessarily match. Consequently, the prediction of the hydraulic conductivity curve from measurements of the water retention behavior in combination with a value for the saturated hydraulic conductivity can be misleading. Thus, separate parameterizations of the individual functions might be necessary and are

  17. Design and verification of additional filtration for the application of ecological transmission and hydraulic fluids in tractorc

    Directory of Open Access Journals (Sweden)

    Pavel Máchal

    2013-01-01

    Full Text Available This contribution presents the design and function verification of additional filtration. It is intended for the common transmission and hydraulic oil filling of tractors. The main role of this filtration concept is to ensure a high level of oil cleanness as a condition for the application of ecologic fluids in tractors. The next one is to decrease the wear of lubricated tractor components, the degradation of oil and eventually to extend the interval of oil change. The designed additional filtering is characterized by ease installation through the use of quick couplings and hoses to the external hydraulic circuit. Therefore, the filtration is suitable for various tractor types. Filter element has been designed with the filter ability 1micron and the ability to separate to 0.5 dm3 of water from oil. Function of additional filtration was verified during the 150 engine hours of tractor operation. During this time period the oil contamination was evaluated on the basis of chemical elements content such as Fe, Cu, Si, Al, Ni, Mo and Cr. The additive concentration was evaluated on the basis of chemical elements content such as Ca, P and Zn. During the test operation of tractor the concentration decrease of chemical elements reached the values 25.53 % (Fe, 23.53 % (Si, 25 % (Al and 5.5 % (Cu. The decrease of additive concentration reached only medium level (6.6 %. Therefore, the designed additional filtration doesn’t remove additives from oil. Based on the evaluation of the content of chemical elements (that representing contamination and additives, we can say that the designed filtering method is suitable for use in agricultural tractors.

  18. GENERAL EQUATION OF THE HYDRAULIC FRICTION LAW FOR HINDERED FALLING OF AN INDIVIDUAL BALL AND FLUID MOTION IN GRANULAR LAYERS

    Directory of Open Access Journals (Sweden)

    M. V. Krautsov

    2015-01-01

    Full Text Available The article presents the results of a research into various hydromechanical processes such as hindered falling of an individual ball in a liquid; suspension of a homogeneous monodispersed granular layer with ascending fluid flow; homogeneous liquid filtration in a porous granular layer. The authors generalize the results of theoretical and experimental studies, employ the theory of similarity, and establish that the laws of hydraulic friction for the mentioned hydromechanical processes share the common ground described by one general equation that provides basis for obtaining the individual formulae computing the studied hydromechanical processes. The formulae appear in dimensionless similitude parameters that reflect correlation of the essential action forces.The presented scientific results contribute to the theory development of the applied hydromechanical phenomena and the new obtained formulae enable enhancement of the calculation procedures for structures and installations that realize the studied hydraumechanical processes. Thus, the research results for the hindered falling of an individual ball in a liquid can apply in viscosimetry techniques and in handling the problems related to calculations of various movement types and separate units in technologies realizing the hydraulic processes of hindered falling of individual balls in liquids.Fluidization processes (pseudo-liquefaction of the granular layers enjoy wide application in various segments of industry for instance in chemical engineering at adsorption, desorption, dissolution, dealkalization, ablution. A new general calculating formula incipiency provides a possibility for technological computations realization under any operational mode. The filtration process is used in industry as well as occurs in nature, for example, in movement of the ground water. At present, the basis for calculating techniques is the monomial Darcy formula defining the filtering rate as function of the

  19. Improving the Hydraulic Efficiency of Centrifugal Pumps through Computational Fluid Dynamics Based Design optimization

    Directory of Open Access Journals (Sweden)

    Abdellah Ait moussa

    2014-08-01

    Full Text Available The design and optimization of turbo machine impellers such as those in pumps and turbines is a highly complicated task due to the complex three-dimensional shape of the impeller blades and surrounding devices. Small differences in geometry can lead to significant changes in the performance of these machines. We report here an efficient numerical technique that automatically optimizes the geometry of these blades for maximum performance. The technique combines, mathematical modeling of the impeller blades using non-uniform rational B-spline (NURBS, Computational fluid dynamics (CFD with Geometry Parameterizations in turbulent flow simulation and the Globalized and bounded Nelder-Mead (GBNM algorithm in geometry optimization.

  20. Study of high-pressure adsorption from supercritical fluids by the potential theory

    DEFF Research Database (Denmark)

    Monsalvo, Matias Alfonso; Shapiro, Alexander

    2009-01-01

    The multicomponent potential theory of adsorption (MPTA), which has been previously used to study low-pressure adsorption of subcritical fluids, is extended to adsorption equilibria from supercritical fluids up to high pressures. The MPTA describes an adsorbed phase as an inhomogeneous fluid...... with thermodynamic properties that depend on the distance from the solid surface (or position in the porous space). The description involves the two kinds of interactions present in the adsorbed fluid, i.e. the fluid-fluid and fluid-solid interactions. accounted for by means of an equation of state (Eo......S) and interaction potential functions, respectively. This makes it possible to generate the different MPTA models by combination of the relevant EoS/potentials. In the present work, the simplified perturbed-chain statistical associating fluid theory (sPC-SAFT) EoS is used for the thermodynamic description of both...

  1. Pressure Regulation in Nonlinear Hydraulic Networks by Positive and Quantized Controls

    NARCIS (Netherlands)

    Persis, Claudio De; Kallesøe, Carsten Skovmose

    2011-01-01

    We investigate an industrial case study of a system distributed over a network, namely, a large-scale hydraulic network which underlies a district heating system. The network comprises an arbitrarily large number of components (valves, pipes, and pumps). After introducing the model for this class of

  2. Critical hydraulic pressure forecasting of water inrush in coal seam floors based on a genetic algorithm-neural network

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, M.; Shi, C.; Liu, T. [China Academy of Safety Science and Technology, Beijing (China); Fu, T. [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering

    2008-08-15

    This paper presented a method of forecasting water inrush in coal seam floors. The theoretical forecasting method used a combined genetic algorithm-neural network method to analyze the relationships between the critical pressure of water inrush and the different conditions in coal seam floors. Actual measurement data from Chinese coal mines were used to train the multi-layer feedforward neural network. Genetic algorithms were used to train the neural networks and optimize the neural network topology. The topology structure of the network was selected by considering population size, mutation rate, and crossing rates. The critical hydraulic pressure of water inrush was then predicted, and predictions were compared with measurements taken to validate the method. Results of the study showed that the forecasting method improved learning efficiency and the prediction capacity of the network. It was concluded that the combined method can be used to accurately predict the critical hydraulic pressure of water inrush on coal seam floors. 28 refs., 1 tab., 7 figs.

  3. Properties Research of Water-polyols Fire Resistant Hydraulic Fluid%水-多元醇型难燃液压液的性能研究

    Institute of Scientific and Technical Information of China (English)

    宋开财; 沈国钦; 王建华; 李春生; 宋敏

    2012-01-01

    The major physical and chemical properties of fire resistant hydraulic fluids with different composition have been analyzed, such as fire-resistant, viscosity-temperature and evaporation characteristics. The influences of different water content, different types of polyols and tackifier on the main properties of water based fire resistant hydraulic fluid have been studied. Hie results show that the higher water content of water based fire resistant hydraulic fluid, the better the flame resistance is, and the higher the evaporation rate. The rule of change at evaporation rate along with time was first increased and then decreased. The low temperature performance of water-glycol-based hydraulic fluid was better, but the air releasing property and the susceptibility on thickening agent of water-glycerol-based hydraulic fluid were better. The thickening ability of water-soluble polyether is far superior to polyethylene glycol, with no crystallization phenomena at low temperature. The study results are of certain reference significance to the research and application of water-based fire resistant hydraulic fluid.%分析了不同组成难燃液压液的难燃性、黏温特性和蒸发特性等主要理化性能,研究了不同含水量、不同类型多元醇和增黏剂对水基难燃液压液主要性能的影响.结果表明:水基难燃液压液的水含量越高,难燃性越好,蒸发率越高,且蒸发率随时间的变化规律是先增大后减少.水-乙二醇型液压液的低温性能较好,水-甘油型液压液的空气释放性和对稠化剂的感受性较好.水溶性聚醚的稠化能力远远优于聚乙二醇,低温时无结晶现象.研究结果对于水基难燃液压液的配方研究和使用具有参考意义.

  4. Life Cycle Assessment of age-related environmental impact of biogenic hydraulic fluids; Life Cycle Assessment der alterungsbedingten Umweltvertraeglichkeit biogener Hydraulik-Schmierstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Bressling, Jana

    2012-07-01

    Biogenic hydraulic fluids, based on synthetic esters (category: HEES), have an excellent environmental profile in the unused state, so that they are typically classified into water hazard class 1 or as ''not hazardous to water''. During storage at room temperature and tribological application, occurring chemical and toxicological changes take no account in the classification of lubricants until now. However, the ageing and oxidation stability gets increasing importance, since it determines the service life of lubricants in tribological systems in addition to the storage time. Since it always comes to direct and uncontrolled entries into the environment in case of accidents or hydraulic leaks, it is essential to assess whether there is an environmental hazard by waste oils. With an increased use of biogenic hydraulic fluids in environmentally sensitive areas, thus the need for an appropriate monitoring and assessment approach as part of a Life Cycle Assessment (LCA). The aquatic and miniaturised test procedures applied in this work with the Water Soluble Fraction (WSF) concept, allows a simple and quick screening of age-related ecotoxic potential of lubricants by oxidative processes and tribological application. For detection of genotoxic potential the umu-test is a suitable indicator test to detect geno- and cytotoxic effects by oxidative reactions. The determination of biodegradability is essential for the assessment of the environmental impact of hydraulic fluids. The optimised biodegradability test system ''O2/CO2-Headspace Test'' has proved itself as a suitable procedure for the investigation of biogenic lubricants within the scope of a LCA and shows therefore a comparable method of the required test procedures for the assignment of ecolabels. In addition, the combination of biological test procedures and chemical analysis allows a comprehensive investigation of effects and causes of age-related changes of hydraulic

  5. Review and prospect of research on hydraulic pulsation attenuator

    Science.gov (United States)

    Shan, Chang-ji; Zhao, Qi-jun; Dai, Ting-ting; Bian, Yi-duo; Cai, Yan

    2017-09-01

    The pressure pulsation attenuator is able to decrease the fluid fluctuation of the hydraulic pump effectively, so it is widely used in construction machinery. This paper reviews the history and progresses of the research on the pressure pulsation attenuator in China and overseas, summarizes its two types: H-type rigid structure and built-in flexible material, meanwhile, discusses its future research area.

  6. Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones

    Science.gov (United States)

    Doughty, Christine; Tsang, Chin-Fu; Rosberg, Jan-Erik; Juhlin, Christopher; Dobson, Patrick F.; Birkholzer, Jens T.

    2016-11-01

    Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

  7. Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones

    Science.gov (United States)

    Doughty, Christine; Tsang, Chin-Fu; Rosberg, Jan-Erik; Juhlin, Christopher; Dobson, Patrick F.; Birkholzer, Jens T.

    2017-03-01

    Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

  8. Nucleation of frictional instability caused by fluid pressurization in subducted blueschist

    NARCIS (Netherlands)

    Sawai, M.; Niemeijer, A.R.|info:eu-repo/dai/nl/370832132; Plümper, O.|info:eu-repo/dai/nl/37155960X; Hirose, T.; Spiers, C.J.|info:eu-repo/dai/nl/304829323

    2016-01-01

    Pore pressure is an important factor in controlling the slip instability of faults and thus the generation of earthquakes. Particularly slow earthquakes are widespread in subduction zones and usually linked to the occurrence of high pore pressure. Yet the influence of fluid pressure and effective st

  9. Phase equilibria in fluid mixtures at high pressures: The He-CH4 system

    Science.gov (United States)

    Streett, W. B.; Erickson, A. L.; Hill, J. L. E.

    1972-01-01

    An experimental study of phase equilibria in the He-CH4 system was carried out over the temperature range 95 to 290 K and at pressures to 10,000 atm. The experimental results consist of equilibrium phase composition for twenty-eight isotherms in the region of coexistence of two fluid phases, together with the pressure-temperature trace of the three-phase boundary at which a CH4-rich solid phase is in equilibrium with the two fluid phases. The system exhibits a fluid-fluid phase separation which persists to temperatures and pressures beyond the range of this experiment. These results, together with those recently obtained for other binary systems, provide information about the form of phase diagrams for binary gas mixtures in the region of pressure induced phase transitions at high pressures. These findings are relevant to problems of deep atmosphere and interior structures in the outer planets.

  10. Hydraulic Calculation Method for the Fluid Delivery System of Centrifugal Pump%离心泵流体输送系统水力计算方法

    Institute of Scientific and Technical Information of China (English)

    徐宏斌

    2001-01-01

    简述离心泵和管路的特性,介绍离心泵流体输送管路系统的水力计算方法,以及如何确定泵的安装高度。%The characteristics of centrifugal pump and pipeline are brieflyelaborated. The hydraulic calculation method for fluid delivery pipeline system of centrifugal pump and the method of determining the pump installation height are introduced.

  11. Intraocular pressure and estimated cerebrospinal fluid pressure. The Beijing Eye Study 2011.

    Directory of Open Access Journals (Sweden)

    Ya Xing Wang

    Full Text Available PURPOSE: To examine a potential association between intraocular pressure (IOP and cerebrospinal fluid pressure (CSFP in a population-based setting. METHODS: The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range: 50-93 years. A detailed ophthalmic examination was performed. Based on a previous study with lumbar cerebrospinal fluid pressure (CSFP measurements, CSFP was calculated as CSFP [mm Hg] = 0.44×Body Mass Index [kg/m2]+0.16×Diastolic Blood Pressure [mm Hg]-0.18×Age [Years]. RESULTS: In multivariate analysis, IOP was associated with higher estimated CSFP (P<0.001; standardized correlation coefficient beta: 0.27; regression coefficient B: 0.20; 95% confidence interval (CI: 0.16, 0.24, after adjusting for thinner central corneal thickness (P<0.001; beta: 0.45; B: 0.04;95%CI: 0.04,0.04, smaller corneal curvature radius (P<0.001; beta:-0.11; B:-1.13;95%CI:-1.61,-0.64, shallower anterior chamber depth (P = 0.01; beta:-0.05; B:-0.33;95%CI:-0.59,-0.08 and longer axial length (P = 0.002; beta: 0.08; B: 0.20;95%CI: 0.08,0.32, and after adjusting for the systemic parameters of higher pulse rate (P<0.001; beta: 0.08; B: 0.02;95%CI: 0.01,0.03, higher prevalence of arterial hypertension (P = 0.002; beta: 0.06; B: 0.32;95%CI: 0.12,0.53, frequency of drinking alcohol (P = 0.02; beta: 0.04; B: 0.09;95%CI: 0.01,0.17, higher blood concentration of triglycerides (P = 0.001; beta: 0.06; B: 0.06;95%CI: 0.02,0.10 and cholesterol (P = 0.049; beta: 0.04; B: 0.08;95%CI: 0.00,0.17, and body mass index (P<0.001; beta:-0.13; B:-0.09;95%CI:-0.13,-0.06. In a parallel manner, estimated CSFP (mean: 10.8±3.7 mm Hg was significantly associated with higher IOP (P<0.001; beta: 0.13; B: 0.18;95%CI: 0.13,0.23 after adjusting for rural region of habitation (P<0.001; beta:-0.37; B:-2.78;95%CI:-3.07,-2.48, higher systolic blood pressure (P<0.001; beta: 0.34; B: 0.06;95%CI: 0.05,0.07, higher

  12. An approximate solution for a penny-shaped hydraulic fracture that accounts for fracture toughness, fluid viscosity and leak-off

    Science.gov (United States)

    Dontsov, E. V.

    2016-12-01

    This paper develops a closed-form approximate solution for a penny-shaped hydraulic fracture whose behaviour is determined by an interplay of three competing physical processes that are associated with fluid viscosity, fracture toughness and fluid leak-off. The primary assumption that permits one to construct the solution is that the fracture behaviour is mainly determined by the three-process multiscale tip asymptotics and the global fluid volume balance. First, the developed approximation is compared with the existing solutions for all limiting regimes of propagation. Then, a solution map, which indicates applicability regions of the limiting solutions, is constructed. It is also shown that the constructed approximation accurately captures the scaling that is associated with the transition from any one limiting solution to another. The developed approximation is tested against a reference numerical solution, showing that accuracy of the fracture width and radius predictions lie within a fraction of a per cent for a wide range of parameters. As a result, the constructed approximation provides a rapid solution for a penny-shaped hydraulic fracture, which can be used for quick fracture design calculations or as a reference solution to evaluate accuracy of various hydraulic fracture simulators.

  13. Evaluation of pancreatic tissue fluid pressure measurements intraoperatively and by sonographically guided fine-needle puncture

    DEFF Research Database (Denmark)

    Ebbehøj, N; Borly, L; Bülow, J;

    1990-01-01

    The aim of the present study was to evaluate the needle method for pancreatic tissue fluid pressure measurements. Clinical evaluation was performed in 24 patients with chronic pancreatitis, comparing repeated pressure measurements via sonographically guided fine-needle puncture and intraoperative...... pressure measurements by direct puncture of pancreatic tissue and duct. In patients with chronic pancreatitis we found small week-to-week variations in sonographically guided percutaneous pressure measurements and good agreement between preoperative percutaneous pressure measurements and intraoperative...... external pressure levels. The basic calibration of the method evaluated by means of this pressure chamber study showed sufficient precision and accuracy of the needle technique for clinical and investigative purposes. In conclusion, our results suggest that pancreatic tissue fluid pressure can be reliably...

  14. An Experimental Study of Measuring Oscillatory and Transient Pressures in Hydraulic Systems.

    Science.gov (United States)

    1978-12-01

    dynamic conditions. One of these computer programs that was of interest in this study was the Hydraulic Systems Frequency Response (HsFR). H- SFR program...reason for that failure is that the model for the hose was not accurate enough. The predicted amplitudes were much lower than measurec’ values except...the line. 6. P(%)- in line - Pclanp on x 100 ( 6 Pin line 7. Span - The distance between two clamps. The trans- ducers were located in the center of the

  15. 液压管路流固耦合振动机理及控制研究现状与发展%Research Status and Trends on Fluid-structure Interaction Vibration Mechanism and Control of Hydraulic Pipeline

    Institute of Scientific and Technical Information of China (English)

    权凌霄; 孔祥东; 俞滨; 白欢欢

    2015-01-01

    液压管路系统由于存在多物理场、多尺度及流固耦合非线性等特性,因此其振动特性复杂,且危害很大。又由于工业生产的需求,液压系统正逐步向高压高速和高功重比方向发展,又使得液压管路振动的产生和传播机理变得更为复杂。因此有必要对液压管路的振动机理和控制方法及其研究现状进行总结和分析。阐述液压管路振动的危害性和复杂性,并结合近十年来国内外专家学者对于液压管路振动模型的研究内容,在对考虑多场、多尺度及流固耦合因素影响的液压管路振动机理进行总结的基础上,对液压管路流固耦合线性化动力学模型和非线性振动模型的研究成果进行分析,并对液压管路被动、主动及半主动振动控制的研究进展及研究成果进行评述,在此基础上提出今后液压管路系统流固耦合振动机理及振动控制研究的发展趋势。%Because of the effects of multi-physics, multi-scale and fluid-structure interaction(FSI), the vibration characteristics of the hydraulic pipeline system is not only complex, but also harmful. Due to the demand of the industrial production, the hydraulic system is gradually to develop in the direction of high pressure, high speed and high power ratio, which makes the production and propagation mechanism of hydraulic pipeline vibration become more complex. So it is necessary to summary and analyze the research status of the vibration mechanism and control method of hydraulic pipeline. Harmfulness and complexity of hydraulic pipeline vibration are expounded. Combined with the research on hydraulic pipeline vibration and dynamic model which the domestic and abroad experts are committed to in last ten years, hydraulic piping vibration mechanism, in which effects of multi-physics, multi-scale and FSI is taken into account, is summarized. On this basis, some research such as hydraulic pipeline of FSI linear

  16. Prediction of pressure drop in fluid tuned mounts using analytical and computational techniques

    Science.gov (United States)

    Lasher, William C.; Khalilollahi, Amir; Mischler, John; Uhric, Tom

    1993-11-01

    A simplified model for predicting pressure drop in fluid tuned isolator mounts was developed. The model is based on an exact solution to the Navier-Stokes equations and was made more general through the use of empirical coefficients. The values of these coefficients were determined by numerical simulation of the flow using the commercial computational fluid dynamics (CFD) package FIDAP.

  17. Investigation of Valve Plate in Water Hydraulic Axial Piston Motor

    Institute of Scientific and Technical Information of China (English)

    聂松林; 李壮云; 等

    2002-01-01

    This paper has introduced the developments of water hydraulic axial piston equipments.According to the effects of physicochemical properties of water on water hydraulic components,a novel valve plate for water hydraulic axial motor has been put forward,whose moment exerted by the fluid field between valve plate and bearing plate is balanced entirely.The material screening experiment of valve plate is done on the test rig.Through numerical simulation the effects of some geometry parameters on the performance of water hydraulic motor have been studied.The silencing grooves on the valve plate in water hydraulic motor can reduce the pressure shock and the occurrence of cavitation effectively.It is evident that the appropriate structure should change the wear status between matching paris and reduces the wear and specific pressure of the matching pairs.The specimen with the new type valve plate is used in a tool system.

  18. Vaginal pressure during lifting, floor exercises, jogging, and use of hydraulic exercise machines.

    Science.gov (United States)

    O'Dell, Katharine K; Morse, Abraham N; Crawford, Sybil L; Howard, Allison

    2007-12-01

    We recorded vaginal pressure in 12 women without risk factors for prolapse during two activity and exercise sessions, compared exercise and cough pressure, and evaluated method reproducibility and patterns of relative pressure. Portable urodynamic equipment, repeated measures descriptive design, and purposeful sampling were used with nonparametric analysis and visual comparison of pressure graphs. Mean participant age was 31.1 years (range 20-51), and mean body mass index was 22.7 (range 18.5-29.3). Mean pressures (in cm H(2)O): cough, 98.0 (48.0-133.7); standing, 24.0 (15.9-28.5); supine exercise, 34.0 (6.3-91.9); exercise machines, 37.0 (20.3-182.3). Repeated measures correlations for selected measures ranged from 0.66 (p pressure patterns were not consistent with patterns of group medians. We concluded that vaginal pressure measurement is reproducible in women without prolapse and that studied exercises generally produced lower pressure than cough, but individuals varied in pressure exerted. Individual variations warrant further study.

  19. Pressure in an exactly solvable model of active fluid

    Science.gov (United States)

    Marini Bettolo Marconi, Umberto; Maggi, Claudio; Paoluzzi, Matteo

    2017-07-01

    We consider the pressure in the steady-state regime of three stochastic models characterized by self-propulsion and persistent motion and widely employed to describe the behavior of active particles, namely, the Active Brownian particle (ABP) model, the Gaussian colored noise (GCN) model, and the unified colored noise approximation (UCNA) model. Whereas in the limit of short but finite persistence time, the pressure in the UCNA model can be obtained by different methods which have an analog in equilibrium systems, in the remaining two models only the virial route is, in general, possible. According to this method, notwithstanding each model obeys its own specific microscopic law of evolution, the pressure displays a certain universal behavior. For generic interparticle and confining potentials, we derive a formula which establishes a correspondence between the GCN and the UCNA pressures. In order to provide explicit formulas and examples, we specialize the discussion to the case of an assembly of elastic dumbbells confined to a parabolic well. By employing the UCNA we find that, for this model, the pressure determined by the thermodynamic method coincides with the pressures obtained by the virial and mechanical methods. The three methods when applied to the GCN give a pressure identical to that obtained via the UCNA. Finally, we find that the ABP virial pressure exactly agrees with the UCNA and GCN results.

  20. Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array

    Science.gov (United States)

    Zang, Arno; Stephansson, Ove; Stenberg, Leif; Plenkers, Katrin; Specht, Sebastian; Milkereit, Claus; Schill, Eva; Kwiatek, Grzegorz; Dresen, Georg; Zimmermann, Günter; Dahm, Torsten; Weber, Michael

    2017-02-01

    In this paper, an underground experiment at the Äspö Hard Rock Laboratory (HRL) is described. Main goal is optimizing geothermal heat exchange in crystalline rock mass at depth by multistage hydraulic fracturing with minimal impact on the environment, that is, seismic events. For this, three arrays with acoustic emission, microseismicity and electromagnetic sensors are installed mapping hydraulic fracture initiation and growth. Fractures are driven by three different water injection schemes (continuous, progressive and pulse pressurization). After a brief review of hydraulic fracture operations in crystalline rock mass at mine scale, the site geology and the stress conditions at Äspö HRL are described. Then, the continuous, single-flow rate and alternative, multiple-flow rate fracture breakdown tests in a horizontal borehole at depth level 410 m are described together with the monitoring networks and sensitivity. Monitoring results include the primary catalogue of acoustic emission hypocentres obtained from four hydraulic fractures with the in situ trigger and localizing network. The continuous versus alternative water injection schemes are discussed in terms of the fracture breakdown pressure, the fracture pattern from impression packer result and the monitoring at the arrays. An example of multistage hydraulic fracturing with several phases of opening and closing of fracture walls is evaluated using data from acoustic emissions, seismic broad-band recordings and electromagnetic signal response. Based on our limited amount of in situ tests (six) and evaluation of three tests in Ävrö granodiorite, in the multiple-flow rate test with progressively increasing target pressure, the acoustic emission activity starts at a later stage in the fracturing process compared to the conventional fracturing case with continuous water injection. In tendency, also the total number and magnitude of acoustic events are found to be smaller in the progressive treatment with

  1. Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array

    Science.gov (United States)

    Zang, A.; Stephansson, O.; Stenberg, L.; Plenkers, K.; Specht, S.; Milkereit, C.; Schill, E.; Kwiatek, G.; Dresen, G.; Zimmermann, G.; Dahm, T.; Weber, M.

    2016-11-01

    In this article, an underground experiment at the Äspö Hard Rock Laboratory (HRL) is described. Main goal is optimizing geothermal heat exchange in crystalline rock mass at depth by multi-stage hydraulic fracturing with minimal impact on the environment, i.e. seismic events. For this, three arrays with acoustic emission, microseismicity and electromagnetic sensors are installed mapping hydraulic fracture initiation and growth. Fractures are driven by three different water injection schemes (continuous, progressive, pulse pressurization). After a brief review of hydraulic fracture operations in crystalline rock mass at mine scale, the site geology and the stress conditions at Äspö HRL are described. Then, the continuous, single-flow rate and alternative, multiple-flow rate fracture breakdown tests in a horizontal borehole at depth level 410 m are described together with the monitoring networks and sensitivity. Monitoring results include the primary catalogue of acoustic emission hypocenters obtained from four hydraulic fractures with the in situ trigger and localizing network. The continuous versus alternative water injection schemes are discussed in terms of the fracture breakdown pressure, the fracture pattern from impression packer result and the monitoring at the arrays. An example of multi-stage hydraulic fracturing with several phases of opening and closing of fracture walls is evaluated using data from acoustic emissions, seismic broadband recordings and electromagnetic signal response. Based on our limited amount of in situ tests (six) and evaluation of three tests in Ävrö granodiorite, in the multiple-flow rate test with progressively increasing target pressure, the acoustic emission activity starts at a later stage in the fracturing process compared to the conventional fracturing case with continuous water injection. In tendency, also the total number and magnitude of acoustic events is found to be smaller in the progressive treatment with frequent

  2. Well-conditioning effects on bubblepoint pressure of fluid samples from solution-gas-drive reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, A.C. (Univ. of Tulsa, Tulsa, OK (US)); Peres, A.M.M.; Serra, K.V. (Petrobas (BR)); Macias-Chapa, L. (National Autonomous Univ. of Mexico (MX))

    1990-12-01

    This paper considers the determination of the initial or average reservoir bubblepoint pressure from a fluid sample obtained from a well producing a solution-gas-drive reservoir. It is shown that standard API recommended well-conditioning procedures (rate reductions) for obtaining a single-phase (liquid) bottomhole fluid sample do not always redissolve all free gas. Thus, it is not always possible to obtain a single-phase liquid (oil) bottomhole fluid sample that has a bubblepoint pressure equal to the initial or average reservoir bubblepoint pressure. Moreover, monitoring the producing GOR and bottomhole pressure does not always reliably indicate whether two-phase (oil and gas) or single-phase (oil) flow is prevalent in the near-wellbore region. Contrary to current opinion, it is shown that recombination of surface samples of oil and gas form the producing GOR usually yields reliable estimates of average reservoir bubblepoint pressure.

  3. Experimental Study of Pressure Drop in Compressible Fluid through Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Min Kyo [Hanwha Corporation Defence R and D Center, Daejeon (Korea, Republic of); Kim, Do Hun; Seo, Chan Woo; Lee, Seoung Youn; Jang, Seok Pil; Koo, Jaye [Korea Aerospace Univ., Goyang (Korea, Republic of)

    2013-08-15

    This study proposes the characteristics of the pressure drop in a compressible fluid through porous media for application to a porous injector in a liquid rocket engine in order to improve the uniformity of the drop size distribution and the mixing performance of shear coaxial injectors. The fluid through the porous media is a Non-Darcy flow that shows a Nonlinear relation between the pressure drop and the velocity at high speed and high mass flow rate. The pressure drop of the Non-Darcy flow can be derived using the Ferrochrome equation that includes the losses of viscous and inertia resistance. The permeability and Erg un coefficient represented as a function of the pressure drop and pore size can be applied to the porous injector, where the fluid through the porous media is compressible. A generalized correlation between the pressure drop in relation to the pore size was derived.

  4. Reducing Fatigue Loading Due to Pressure Shift in Discrete Fluid Power Force Systems

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

    2016-01-01

    Discrete Fluid Power Force Systems is one of the topologies gaining focus in the pursuit of lowering energy losses in fluid power transmission systems. The cylinder based Fluid Power Force System considered in this article is constructed with a multi-chamber cylinder, a number of constant pressure...... power force system. The current paper investigates the correlation between pressure oscillations in the cylinder chambers and valve flow in the manifold. Furthermore, the correlation between the pressure shifting time and the pressure overshoot is investigated. The study therefore focus on how to shape...... the valve flow in the manifold to reduce the added fatigue loads. A simple transmission line model is developed for the analysis. Two inputs are given in the Laplace domain and the time domain solution of the cylinder pressure to the given inputs are derived through inverse Laplace transformation. Based...

  5. Nuclear Engineering Computer Modules, Thermal-Hydraulics, TH-1: Pressurized Water Reactors.

    Science.gov (United States)

    Reihman, Thomas C.

    This learning module is concerned with the temperature field, the heat transfer rates, and the coolant pressure drop in typical pressurized water reactor (PWR) fuel assemblies. As in all of the modules of this series, emphasis is placed on developing the theory and demonstrating its use with a simplified model. The heart of the module is the PWR…

  6. Intracochlear Fluid Pressure Changes Related to the Insertional Speed of a CI Electrode

    Directory of Open Access Journals (Sweden)

    I. Todt

    2014-01-01

    Full Text Available Introduction. To preserve residual hearing the atraumaticity of the cochlea electrode insertion has become a focus of cochlear implant research. In addition to other factors, the speed of insertion is thought to be a contributing factor in the concept of atraumatic implantation. The aim of our study was to observe intracochlear fluid pressure changes due to different insertional speeds of an implant electrode in a cochlear model. Materials and Methods. The experiments were performed using an artificial cochlear model. A linear actuator was mounted on an Advanced Bionics IJ insertional tool. The intracochlear fluid pressure was recorded through a pressure sensor which was placed in the helicotrema area. Defined insertions were randomly performed with speeds of 0.1 mm/sec, 0.25 mm/sec, 0.5 mm/sec, 1 mm/sec, and 2 mm/sec. Results. A direct correlation between speed and pressure was observed. Mean maximum values of intracochlear fluid pressure varied between 0.41 mm Hg and 1.27 mm Hg. Conclusion. We provide the first results of fluid pressure changes due to insertional speeds of CI electrodes in a cochlear model. A relationship between the insertional speed and intracochlear fluid pressure was observed. Further experiments are needed to apply these results to the in vivo situation.

  7. Prediction of pressure fluctuation of a hydraulic turbine at no-load condition

    Science.gov (United States)

    Chen, T. J.; Wu, X. J.; Liu, J. T.; Wu, Y. L.

    2015-01-01

    In order to study characteristics of pressure fluctuation of a turbine during the starting period, a turbine with guide vanes device at no-load condition was investigated using RNG k-epsilon turbulence model. The inner flow distribution and pressure fluctuation characteristics were analyzed. Results show that the pressure fluctuations in the region between the runner and guide vanes are different around the runner inlet. The dominant frequency of pressure fluctuation in the vaneless space close to the casing outlet is the blade passing frequency, while the dominant frequency at the rest region is the twice of the blade passing frequency. The increase of amplitude of pressure fluctuation close to the casing outlet can be attribute to the large scale stall at suction side of the runner inlet.

  8. Data regarding hydraulic fracturing distributions and treatment fluids, additives, proppants, and water volumes applied to wells drilled in the United States from 1947 through 2010

    Science.gov (United States)

    Gallegos, Tanya J.; Varela, Brian A.

    2015-01-01

    Comprehensive, published, and publicly available data regarding the extent, location, and character of hydraulic fracturing in the United States are scarce. The objective of this data series is to publish data related to hydraulic fracturing in the public domain. The spreadsheets released with this data series contain derivative datasets aggregated temporally and spatially from the commercial and proprietary IHS database of U.S. oil and gas production and well data (IHS Energy, 2011). These datasets, served in 21 spreadsheets in Microsoft Excel (.xlsx) format, outline the geographical distributions of hydraulic fracturing treatments and associated wells (including well drill-hole directions) as well as water volumes, proppants, treatment fluids, and additives used in hydraulic fracturing treatments in the United States from 1947 through 2010. This report also describes the data—extraction/aggregation processing steps, field names and descriptions, field types and sources. An associated scientific investigation report (Gallegos and Varela, 2014) provides a detailed analysis of the data presented in this data series and comparisons of the data and trends to the literature.

  9. A photonic wall pressure sensor for fluid mechanics applications.

    Science.gov (United States)

    Manzo, M; Ioppolo, T; Ayaz, U K; Lapenna, V; Ötügen, M V

    2012-10-01

    In this paper, we demonstrate a micro-optical wall pressure sensor concept based on the optical modes of dielectric resonators. The sensing element is a spherical micro-resonator with a diameter of a few hundred micrometers. A latex membrane that is flush mounted on the wall transmits the normal pressure to the sensing element. Changes in the wall pressure perturb the sphere's morphology, leading to a shift in the optical modes. The wall pressure is measured by monitoring the shifts in the optical modes. Prototype sensors with polydimethylsiloxane micro-spheres are tested in a steady two-dimensional channel flow and in a plane wave acoustic tube. Results indicate sensor resolutions of ∼20 mPa and bandwidth of up to 2 kHz.

  10. Predictive permeability model of faults in crystalline rocks; verification by joint hydraulic factor (JH) obtained from water pressure tests

    Science.gov (United States)

    Barani, Hamidreza Rostami; Lashkaripour, Gholamreza; Ghafoori, Mohammad

    2014-08-01

    In the present study, a new model is proposed to predict the permeability per fracture in the fault zones by a new parameter named joint hydraulic factor (JH). JH is obtained from Water Pressure Test (WPT) and modified by the degree of fracturing. The results of JH correspond with quantitative fault zone descriptions, qualitative fracture, and fault rock properties. In this respect, a case study was done based on the data collected from Seyahoo dam site located in the east of Iran to provide the permeability prediction model of fault zone structures. Datasets including scan-lines, drill cores, and water pressure tests in the terrain of Andesite and Basalt rocks were used to analyse the variability of in-site relative permeability of a range from fault zones to host rocks. The rock mass joint permeability quality, therefore, is defined by the JH. JH data analysis showed that the background sub-zone had commonly core had permeability characteristics nearly as low as the outer damage zone, represented by 8 Lu (1.3 ×10-4 m 3/s) per fracture, with occasional peaks towards 12 Lu (2 ×10-4 m 3/s) per fracture. The maximum JH value belongs to the inner damage zone, marginal to the fault core, with 14-22 Lu (2.3 ×10-4-3.6 ×10-4 m 3/s) per fracture, locally exceeding 25 Lu (4.1 ×10-4 m 3/s) per fracture. This gives a proportional relationship for JH approximately 1:4:2 between the fault core, inner damage zone, and outer damage zone of extensional fault zones in crystalline rocks. The results of the verification exercise revealed that the new approach would be efficient and that the JH parameter is a reliable scale for the fracture permeability change. It can be concluded that using short duration hydraulic tests (WPTs) and fracture frequency (FF) to calculate the JH parameter provides a possibility to describe a complex situation and compare, discuss, and weigh the hydraulic quality to make predictions as to the permeability models and permeation amounts of different

  11. Predictive permeability model of faults in crystalline rocks; verification by joint hydraulic factor (JH) obtained from water pressure tests

    Indian Academy of Sciences (India)

    Hamidreza Rostami Barani; Gholamreza Lashkaripour; Mohammad Ghafoori

    2014-08-01

    In the present study, a new model is proposed to predict the permeability per fracture in the fault zones by a new parameter named joint hydraulic factor (JH). JH is obtained from Water Pressure Test WPT) and modified by the degree of fracturing. The results of JH correspond with quantitative fault zone descriptions, qualitative fracture, and fault rock properties. In this respect, a case study was done based on the data collected from Seyahoo dam site located in the east of Iran to provide the permeability prediction model of fault zone structures. Datasets including scan-lines, drill cores, and water pressure tests in the terrain of Andesite and Basalt rocks were used to analyse the variability of in-site relative permeability of a range from fault zones to host rocks. The rock mass joint permeability quality, therefore, is defined by the JH. JH data analysis showed that the background sub-zone had commonly > 3 Lu (less of 5 × 10−5 m3/s) per fracture, whereas the fault core had permeability characteristics nearly as low as the outer damage zone, represented by 8 Lu (1.3 × 10−4 m3/s) per fracture, with occasional peaks towards 12 Lu (2 × 10−4 m3/s) per fracture. The maximum JH value belongs to the inner damage zone, marginal to the fault core, with 14–22 Lu (2.3 × 10−4 –3.6 × 10−4 m3/s) per fracture, locally exceeding 25 Lu (4.1 × 10−4 m3/s) per fracture. This gives a proportional relationship for JH approximately 1:4:2 between the fault core, inner damage zone, and outer damage zone of extensional fault zones in crystalline rocks. The results of the verification exercise revealed that the new approach would be efficient and that the JH parameter is a reliable scale for the fracture permeability change. It can be concluded that using short duration hydraulic tests (WPTs) and fracture frequency (FF) to calculate the JH parameter provides a possibility to describe a complex situation and compare, discuss, and weigh the hydraulic quality to make

  12. Phase equilibria in fluid mixtures at high pressures - The He-CH4 system.

    Science.gov (United States)

    Streett, W. B.; Erickson, A. L.; Hill, J. L. E.

    1972-01-01

    An experimental study of phase equilibria in the He-CH4 system has been carried out over the temperature range 95 to 290 K and at pressures to 10,000 atm. The experimental results consist of equilibrium phase composition for twenty-eight isotherms in the region of coexistence of two fluid phases, together with the pressure-temperature trace of the three-phase boundary at which a CH4-rich solid phase is in equilibrium with the two fluid phases. The system exhibits a fluid-fluid phase separation which persists to temperatures and pressures beyond the range of this experiment. These findings are relevant to problems of deep atmosphere and interior structures in the outer planets.-

  13. Electrical conductivity measurements of aqueous fluids under pressure with a hydrothermal diamond anvil cell.

    Science.gov (United States)

    Ni, Huaiwei; Chen, Qi; Keppler, Hans

    2014-11-01

    Electrical conductivity data of aqueous fluids under pressure can be used to derive the dissociation constants of electrolytes, to assess the effect of ionic dissociation on mineral solubility, and to interpret magnetotelluric data of earth's interior where a free fluid phase is present. Due to limitation on the tensile strength of the alloy material of hydrothermal autoclaves, previous measurements of fluid conductivity were mostly restricted to less than 0.4 GPa and 800 °C. By adapting a Bassett-type hydrothermal diamond anvil cell, we have developed a new method for acquiring electrical conductivity of aqueous fluids under pressure. Our preliminary results for KCl solutions using the new method are consistent with literature data acquired with the conventional method, but the new method has great potential for working in a much broader pressure range.

  14. Fluid input control in burned patients with the aid of ultrasonic arterial blood pressure monitoring.

    Science.gov (United States)

    Banssillon, V; Latarjet, J

    1975-01-01

    Arterial blood pressure is nowadays easily and reliably measured with ultrasonic equipment. It correlates well with blood volume, and may therefore be used to guide fluid infusion in burned patients. Monitoring of blood pressure, instead of application of old-fashioned recipes, helps to avoid dangerous situations of hypovolemia or overload.

  15. Primary low cerebrospinal fluid pressure syndrome with galactorrhea: findings at MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sawada, A.; Morita, N.; Yoshida, S.; Yamamoto, M.; Hashimoto, K. [Kochi Medical School (Japan)

    1996-04-01

    A case of primary low cerebrospinal fluid (CSF) pressure syndrome with galactorrhea is reported. Magnetic resonance imaging demonstrated diffusely enhanced meninges, edematous brian, and enlarged pituitary gland. Coincidental enlargement of pituitary gland and edematous brain due to low CSF pressure compressed the pituitary portal system. The low-perfused anterior lobe of pituitary gland would be the mechanism of galactorrhea. 13 refs., 2 figs.

  16. The potential for spills and leaks of hydraulic fracturing related fluids on well sites and from road incidents.

    Science.gov (United States)

    Clancy, Sarah; Worrall, Fred; Davies, Richard; Gluyas, Jon

    2017-04-01

    recovered. The most common cause of leakage each year is equipment failure; these results highlight the need for good regulation and maintenance onsite. The UK's Institute of Directors suggests several shale gas production scenarios for the UK and how this would influence truck movement. One of their scenarios suggests the development of well pads with 10-wells and 40 laterals (one well pad with 10 well each with 4 laterals). This type of well pad would be projected to use 544,000 m3 of water, which would generate between 11155-31288 truck movements over 20 years, or 6.1-17.1 per day if averaged over 5 years. Dairy farmers in the UK produce 11 million m3 of milk a year, which if the tanker has a capacity of 30 m3, equates to approximately 366667 milk tanker journeys a year. This study assesses the number of road incidents and milk tanker spills and predicts the likelihood of such events for fluids involved in hydraulic fracturing.

  17. High pressure induced phase transition and superdiffusion in anomalous fluid confined in flexible nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Bordin, José Rafael, E-mail: josebordin@unipampa.edu.br [Campus Caçapava do Sul, Universidade Federal do Pampa, Caixa Postal 15051, CEP 96570-000, Caçapava do Sul, RS (Brazil); Krott, Leandro B., E-mail: leandro.krott@ufrgs.br; Barbosa, Marcia C., E-mail: marcia.barbosa@ufrgs.br [Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS (Brazil)

    2014-10-14

    The behavior of a confined spherical symmetric anomalous fluid under high external pressure was studied with Molecular Dynamics simulations. The fluid is modeled by a core-softened potential with two characteristic length scales, which in bulk reproduces the dynamical, thermodynamical, and structural anomalous behavior observed for water and other anomalous fluids. Our findings show that this system has a superdiffusion regime for sufficient high pressure and low temperature. As well, our results indicate that this superdiffusive regime is strongly related with the fluid structural properties and the superdiffusion to diffusion transition is a first order phase transition. We show how the simulation time and statistics are important to obtain the correct dynamical behavior of the confined fluid. Our results are discussed on the basis of the two length scales.

  18. Laboratory Hydraulic Fracturing Experiments for Determining Reopening and Closing Pressures of Fractures

    National Research Council Canada - National Science Library

    IMAI, Tadao; KAMOSHIDA, Naoto; KATO, Harumi; SUGIMOTO, Fumio

    2009-01-01

    ... in the borehole wall and the triggering of acoustic emissions.In the experiments, we measured the pressures during the reopening and closing of a fracture caused by elastic restitution in a block of rock not subjected to compressive load...

  19. Enhancing the safety and efficiency of the driving gear of coal mining machinery by using water as a hydraulic fluid and enhancing the reliability of scraper-chain conveyors; Erhoehung der Sicherheit und Leistungsfaehigkeit der Antriebstechnik von Arbeitsmaschinen durch Verwendung von Wasserhydraulik sowie Erhoehung der Zuverlaessigkeit der Kettenkratzerfoerderer

    Energy Technology Data Exchange (ETDEWEB)

    Reichel, J.; Boeing, R.; Graetz, A.; Loehning, H.D.; Plum, D.

    1997-12-31

    The objective pursued is to increasingly use water or high water-content fluids as a substitute for other hydraulic fluids in driving gear of mining machinery. The state of the art of the technology is represented only by individual solutions achieved for given purposes which are not suitable for other applications, let alone for coal mining machinery. The research project was to identify hydraulic components that will permit the use of water or watery substances as a hydraulic fluid in mining applications. The components have been found and further developed, and finally systems with linear and rotatory drives have been tested at various test facilities in order to derive information on the system behaviour of pressurized fluids and machinery components and their suitability for coal mining applications. (orig./CB) [Deutsch] In der untertaegigen Antriebstechnik sollen vermehrt Wasser und wasserhaltige Fluessigkeiten eingesetzt werden. Der Stand der Technik fuehrt bei der Anwendung von Wasserhydraulik immer wieder nur Einzelloesungen auf, die nicht allgemein und insbesondere im Steinkohlenbergbau angewendet werden koennen. Im Rahmen dieses Forschungsvorhabens wurden fuer die Wasserhydraulik geeignete Komponenten untersucht, weiterentwickelt und schliesslich Systeme mit linearen und rotatorischen Antrieben auf verschiedenen Pruefstaenden erprobt, um Aussagen ueber das Systemverhalten von Druckfluessigkeit und Bauelementen fuer Bergbauanwendungen zu bekommen. (orig./MSK)

  20. Combined Effect of Pressure and Temperature on the Viscous Behaviour of All-Oil Drilling Fluids

    Directory of Open Access Journals (Sweden)

    Hermoso J.

    2014-12-01

    Full Text Available The overall objective of this research was to study the combined influence of pressure and temperature on the complex viscous behaviour of two oil-based drilling fluids. The oil-based fluids were formulated by dispersing selected organobentonites in mineral oil, using a high-shear mixer, at room temperature. Drilling fluid viscous flow characterization was performed with a controlled-stress rheometer, using both conventional coaxial cylinder and non-conventional geometries for High Pressure/High Temperature (HPHT measurements. The rheological data obtained confirm that a helical ribbon geometry is a very useful tool to characterise the complex viscous flow behaviour of these fluids under extreme conditions. The different viscous flow behaviours encountered for both all-oil drilling fluids, as a function of temperature, are related to changes in polymer-oil pair solvency and oil viscosity. Hence, the resulting structures have been principally attributed to changes in the effective volume fraction of disperse phase due to thermally induced processes. Bingham’s and Herschel-Bulkley’s models describe the rheological properties of these drilling fluids, at different pressures and temperatures, fairly well. It was found that Herschel-Bulkley’s model fits much better B34-based oil drilling fluid viscous flow behaviour under HPHT conditions. Yield stress values increase linearly with pressure in the range of temperature studied. The pressure influence on yielding behaviour has been associated with the compression effect of different resulting organoclay microstructures. A factorial WLF-Barus model fitted the combined effect of temperature and pressure on the plastic viscosity of both drilling fluids fairly well, being this effect mainly influenced by the piezo-viscous properties of the continuous phase.

  1. Characteristics of Abnormal Pressure Systems and Their Responses of Fluid in Huatugou Oil Field, Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiaozhi; XU Hao; TANG Dazhen; ZHANG Junfeng; HU Xiaolan; TAO Shu; CAI Yidong

    2009-01-01

    Based on the comprehensive study of core samples, well testing data, and reservoir fluid properties, the construction and the distribution of the abnormal pressure systems of the Huatugou oil field in Qaidam Basin are discussed. The correlation between the pressure systems and hydrocarbon accumulation is addressed by analyzing the corresponding fluid characteristics. The results show that the Huatugou oil field as a whole has low formation pressure and low fluid energy; therefore, the hydrocarbons are hard to migrate, which facilitates the forming of primary reservoirs. The study reservoirs, located at the Xiayoushashan Formation (N_2~1) and the Shangganchaigou Formation (N_1) are relatively shallow and have medium porosity and low permeability. They are abnormal low-pressure reservoirs with an average formation pressure coefficient of 0.61 and 0.72 respectively. According to the pressure coefficient and geothermal anomaly, the N_1 and N_2~1 Formations belong to two independent temperature-pressure systems, and the former has slightly higher energy. The low-pressure compartments consist of a distal bar as the main body, prodeita mud as the top boundary, and shore and shallow lake mud or algal mound as the bottom boundary. They are vertically overlapped and horizontally paralleled. The formation water is abundant in the Cl~- ion and can be categorized as CaCl_2 type with high salinity, which indicates that the abnormal low-pressure compartments are in good sealing condition and beneficial for oil and gas accumulation and preservation.

  2. Modeling Study of High Pressure and High Temperature Reservoir Fluids

    DEFF Research Database (Denmark)

    Varzandeh, Farhad

    to 250 °C and 2400 bar, in the deep petroleum reservoirs. Furthermore, many of these deep reservoirs are found offshore, including the North Sea and the Gulf of Mexico, making the development even more risky. On the other hand, development of these high pressure high temperature (HPHT) fields can...

  3. Measurement of pleural pressure swings with a fluid-filled esophageal catheter vs pulmonary artery occlusion pressure.

    Science.gov (United States)

    Verscheure, S; Massion, P B; Gottfried, S; Goldberg, P; Samy, L; Damas, P; Magder, S

    2017-02-01

    Pleural pressure measured with esophageal balloon catheters (Peso) can guide ventilator management and help with the interpretation of hemodynamic measurements, but these catheters are not readily available or easy to use. We tested the utility of an inexpensive, fluid-filled esophageal catheter (Peso) by comparing respiratory-induced changes in pulmonary artery occlusion (Ppao), central venous (CVP), and Peso pressures. We studied 30 patients undergoing elective cardiac surgery who had pulmonary artery and esophageal catheters in place. Proper placement was confirmed by chest compression with airway occlusion. Measurements were made during pressure-regulated volume control (VC) and pressure support (PS) ventilation. The fluid-filled esophageal catheter provided a high-quality signal. During VC and PS, change in Ppao (∆Ppao) was greater than ∆Peso (bias = -2 mm Hg) indicating an inspiratory increase in cardiac filling. During VC, ∆CVP bias was 0 indicating no change in right heart filling, but during PS, CVP fell less than Peso indicating an inspiratory increase in filling. Peso measurements detected activation of expiratory muscles, development of non-west zone 3 lung conditions during inspiration, and ventilator-triggered inspiratory efforts. A fluid-filled esophageal catheter provides a high-quality, easily accessible, and inexpensive measure of change in pleural pressure and provided insights into patient-ventilator interactions. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. The role of fluid pressure in fault creep vs. frictional instability: insights from rock deformation experiments on carbonates

    Science.gov (United States)

    Scuderi, Marco M.; Collettini, Cristiano

    2016-04-01

    Fluid overpressure is one of the primary mechanisms for tectonic fault slip. This mechanism is appealing as fluids lubricate the fault and fluid pressure, Pf, reduces the effective normal stress that holds the fault in place. However, current models of earthquake nucleation imply that stable sliding is favored by the increase of pore fluid pressure. Despite this opposite effects, currently, there are only a few studies on the role of fluid pressure under controlled, laboratory conditions. Here, we use laboratory experiments, conducted on a biaxial apparatus within a pressure vessel on limestone fault gouge, to: 1) evaluate the rate- and state- friction parameters as the pore fluid pressure is increased from hydrostatic to near lithostatic values and 2) fault creep evolution as a function of a step increase in fluid pressure. In this second suite of experiments we reached 85% of the maximum shear strength and than in load control we induced fault slip by increasing fluid pressure. Our data show that the friction rate parameter (a-b) evolves from slightly velocity strengthening to velocity neutral behaviour and the critical slip distance, Dc, decreases from about 100 to 20 μm as the pore fluid pressure is increased. Fault creep is slow (i.e 0.001μm/s) away from the maximum shear strength and for small increases in fluid pressure and it accelerates near the maximum shear strength and for larger fluid pressure build-ups, where we observe episodic accelerations/decelerations that in some cases evolve to small dynamic events. Our data suggest that fluid overpressure can increase aseismic creep with the development of frictional instability. Since fault rheology and fault stability parameters change with fluid pressure, we suggest that a comprehensive characterization of these parameters is fundamental for better assessing the role of fluid pressure in natural and human induced earthquakes.

  5. In-line pressure within a HOTLINE® Fluid Warmer, under various flow conditions.

    Science.gov (United States)

    Higashi, Midoriko; Yamaura, Ken; Matsubara, Yukie; Fukudome, Takuya; Hoka, Sumio

    2015-04-01

    Roller pump infusion devices are widely used for rapid infusion, and may be combined with separate warming devices. There may be instances however, where the pressures generated by the roller pump may not be compatible with the warming device. We assessed a commonly used roller pump in combination with a HOTLINE® Fluid Warmer, and found that it could generate pressures exceeding the HOTLINE® manufacturers specifications. This was of concern because the HOTLINE® manufacturer guideline states that not for use with pressure devices generating over 300 mmHg. Pressure greater than 300 mmHg may compromise the integrity of the HOTLINE® Fluid Warming Set. The aim of this study was to compare in-line pressure within a HOTLINE® Fluid Warmer at different infusion rates of a roller pump using various sizes of intravenous cannulae. The rapid infusion system comprised a 500 mL-normal saline bag, roller pump type infusion device, HOTLINE® Fluid Warmer (blood and fluid warmer system), and six different sizes of intravenous cannulae. In-line pressure was measured proximal to the HOTLINE® (pre-warmer) and proximal to the cannula (post-warmer), at flow rate of 50-160 mL/min. The in-line pressures increased significantly with increasing flow rate. The pre-warmer pressures exceeded 300 mmHg when the flow rate was ≥120 mL/min with 20-gauge, 48 mm length cannula, 130 with 20-gauge, 25 mm cannula, and 160 mL/min with 18-gauge, 48 mm cannula. However, they were HOTLINE® could exceed 300 mmHg, depending on the flow rate and size and length of cannula. It is important to pay attention to the size and length of cannulae and flow rate to keep the maximum in-line pressure<300 mmHg when a roller pump type infusion device is used.

  6. The Balance of Fluid and Osmotic Pressures across Active Biological Membranes with Application to the Corneal Endothelium.

    Directory of Open Access Journals (Sweden)

    Xi Cheng

    Full Text Available The movement of fluid and solutes across biological membranes facilitates the transport of nutrients for living organisms and maintains the fluid and osmotic pressures in biological systems. Understanding the pressure balances across membranes is crucial for studying fluid and electrolyte homeostasis in living systems, and is an area of active research. In this study, a set of enhanced Kedem-Katchalsky (KK equations is proposed to describe fluxes of water and solutes across biological membranes, and is applied to analyze the relationship between fluid and osmotic pressures, accounting for active transport mechanisms that propel substances against their concentration gradients and for fixed charges that alter ionic distributions in separated environments. The equilibrium analysis demonstrates that the proposed theory recovers the Donnan osmotic pressure and can predict the correct fluid pressure difference across membranes, a result which cannot be achieved by existing KK theories due to the neglect of fixed charges. The steady-state analysis on active membranes suggests a new pressure mechanism which balances the fluid pressure together with the osmotic pressure. The source of this pressure arises from active ionic fluxes and from interactions between solvent and solutes in membrane transport. We apply the proposed theory to study the transendothelial fluid pressure in the in vivo cornea, which is a crucial factor maintaining the hydration and transparency of the tissue. The results show the importance of the proposed pressure mechanism in mediating stromal fluid pressure and provide a new interpretation of the pressure modulation mechanism in the in vivo cornea.

  7. An Experimental Study of the Corrosion Behavior of Nickel Tungsten Carbide in Some Water-Glycol Hydraulic Fluids for Subsea Applications

    Science.gov (United States)

    Zheng, Lei; Neville, Anne; Gledhill, Andrew; Johnston, David

    2010-02-01

    Corrosion failures of components in electro-hydraulic control systems can have serious consequences for the operation of an entire subsea oil recovery system, especially in water depths more than 150 m (Fleming, Meas. Control, 2000, 33(7), p 207-213). An acceptable reason for this is that seawater ingress can have a great effect on stainless steel 316L, the most commonly used material for the failed components of the direction control valves, since chloride irons destabilize the passive film [Malik et al., Corros. Sci., 1992, 33(11), p 1809-1827; Desalination, 1994, 97(1-3), p 189-197; Al-Malahy and Hodgkiess, Desalination, 2003, 158(1-3), p 35-42]. Other materials, claimed to be seawater tolerant, are starting to be used in this system. However, problems can still exist due to the complex factors relating to the corrosion process and how the environmental parameters affect the corrosion mechanisms. In this work, the corrosion behavior of a nickel tungsten carbide cermet, one of the proposed materials, is compared with stainless steel 316L, in four different water-glycol hydraulic fluids and 50% hydraulic fluid/50% seawater solutions using an electrochemical test methodology. Systematic fluid analysis, which includes GC-MS for organic components and ICP-MS analysis for ionic content, and surface analysis of the material are carried out to assess the corrosion mechanisms. Detailed conclusions are then made to summarize the advantages and disadvantages of nickel tungsten carbide being used in this system. The effects of each factor on the corrosion rates and mechanisms are discussed.

  8. Simplification of hydraulic balance without differential pressure regulators; Vereinfachung des hydraulischen Abgleichs. Wegfall der Differenzdruckregler

    Energy Technology Data Exchange (ETDEWEB)

    Gebauer, Marc [W. Baelz und Sohn GmbH und Co., Heilbronn (Germany)

    2010-12-15

    In many heating systems, it would be possible to reduce the number of armatures to save energy. The author presents an example to show the shortcomings of systems with differential pressure controllers and recirculation pumps and points out the advantages of jet pump control. (orig.)

  9. Aquaporin deletion in mice reduces intraocular pressure and aqueous fluid production.

    Science.gov (United States)

    Zhang, Duo; Vetrivel, L; Verkman, A S

    2002-06-01

    Aquaporin (AQP) water channels are expressed in the eye at sites of aqueous fluid production and outflow: AQP1 and AQP4 in nonpigmented ciliary epithelium, and AQP1 in trabecular meshwork endothelium. Novel methods were developed to compare aqueous fluid dynamics in wild-type mice versus mice lacking AQP1 and/or AQP4. Aqueous fluid production was measured by in vivo confocal microscopy after transcorneal iontophoretic introduction of fluorescein. Intraocular pressure (IOP), outflow, and anterior chamber compliance were determined from pressure measurements in response to fluid infusions using micropipettes. Aqueous fluid volume and [Cl(-)] were assayed in samples withdrawn by micropipettes. In wild-type mice (CD1 genetic background, age 4-6 wk), IOP was 16.0 +/- 0.4 mmHg (SE), aqueous fluid volume 7.2 +/- 0.3 microl, fluid production 3.6 +/- 0.2 microl/h, fluid outflow 0.36 +/- 0.06 microl/h/mmHg, and compliance 0.036 +/- 0.006 microl/mmHg. IOP was significantly decreased by up to 1.8 mmHg (P fluid production by up to 0.9 microl/h in age/litter-matched mice lacking AQP1 and/or AQP4 (outbred CD1 and inbred C57/bl6 genetic backgrounds). However, AQP deletion did not significantly affect outflow, [Cl(-)], volume, or compliance. These results provide evidence for the involvement of AQPs in intraocular pressure regulation by facilitating aqueous fluid secretion across the ciliary epithelium. AQP inhibition may thus provide a novel approach for the treatment of elevated IOP.

  10. Prevention of Pressure Oscillations in Modeling a Cavitating Acoustic Fluid

    Directory of Open Access Journals (Sweden)

    B. Klenow

    2010-01-01

    Full Text Available Cavitation effects play an important role in the UNDEX loading of a structure. For far-field UNDEX, the structural loading is affected by the formation of local and bulk cavitation regions, and the pressure pulses resulting from the closure of the cavitation regions. A common approach to numerically modeling cavitation in far-field underwater explosions is Cavitating Acoustic Finite Elements (CAFE and more recently Cavitating Acoustic Spectral Elements (CASE. Treatment of cavitation in this manner causes spurious pressure oscillations which must be treated by a numerical damping scheme. The focus of this paper is to investigate the severity of these oscillations on the structural response and a possible improvement to CAFE, based on the original Boris and Book Flux-Corrected Transport algorithm on structured meshes [6], to limit oscillations without the energy loss associated with the current damping schemes.

  11. 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

  12. Investigation on the influence of leakage clearance on the flow field and performance of scroll hydraulic pump

    Science.gov (United States)

    Sun, Shuaihui; Huang, Yi; Guo, Pengcheng; Zuo, Juanli; Luo, Xingqi

    2016-11-01

    In the present paper, the computer fluid dynamics(CFD) with dynamic mesh model had been applied in scroll hydraulic pump to obtain its flow field at different leakage clearance. The fluid force on the orbiting scroll, the mass flow rate and the hydraulic efficiency at different leakage clearance were calculated based on the flow field data. The results indicated that when the leakage clearance increased from 0.5mm to 1.5mm, the average pressure, maximum of pressure fluctuation, leakage jet flow velocity, shaft power, cavitation degree decreased and the leakage flow rate increased. If the leakage clearance was 2.0mm, the high pressure discharge fluid flowed through the clearance and led to the increase of the average pressure and fluid force. When the leakage clearance is 1.0mm, the average pressure is far lower than that at the 0.5mm clearance, and the hydraulic efficiency is the highest.

  13. Pressure oscillation induced by composite fluid flow - Physical picture generating low frequency earthquake -

    Science.gov (United States)

    Takashima, S.; Kurita, K.

    2006-12-01

    Recently low frequency (LF) earthquakes have been found to occur in various geophysical settings. Structural inspection of the source region and analysis of focal mechanism suggest the possible role of fluid in the generation process. The nature of fluid expected in the source region should be characterized by multiphase system such as magma and gas bubble, magma and crystal and aqueous fluid and gas bubble, for example. In this system the physical properties of this composite depends on the mutual volume fraction. The volume fraction is variable depending on the flow situation. We consider the link between the flow situation and the volume fraction is an essential part of the composite flow. Here based on the concept that nature of the composite flow plays a central role in the generation of pressure oscillation, we report a simple laboratory model to demonstrate LF earthquakes. The multiphase system in the source region of the LF earthquakes is modeled here as a composite of viscous fluid and incompressible granular phase. plastic particles made of polystyrene (0.5 mm in diameter) and glycerol solution is packed into a cylindrical case (60 mm in diameter). The packing state of the solid phase is near random closed packing state. The glycerol solution flows into the case from the pressure reservoir and it goes out from exit tube with 60 mm in length and 3 mm in diameter. The pressure is measured using a pressure sensor. The control parameter is fluid pressure (1 atm plus 300 Pa to 1500 Pa) and its viscosity (30 mPas to 100 mPas) in this experiment. When the pressure difference between the case is low, the flow is characterized as a permeable flow. Only the interstitial fluid of the glycerol solution flows out depending on the pressure difference. When the pressure difference is above the critical value, both fluid and particles flow out as a composite flow. In this state the output pressure was observed to oscillate. In the diagram of power spectrum of the

  14. Stability Verification for Energy-Aware Hydraulic Pressure Control via Simplicial Subdivision

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Wisniewski, Rafael

    2015-01-01

    This paper presents a linear programming-based method for finding Lyapunov functions of dynamical systems with polynomial vector fields. We propose to utilize a certificate of positivity in the Bernstein basis based on subdivisioning to find a Lyapunov function. The subdivision-based method...... is proposed since it has better degree bounds than similar methods based on degree elevation. The proposed method is successfully applied to find a Lyapunov function for a pressure controlled water distribution system....

  15. 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.

  16. Trends in Design of Water Hydraulics

    DEFF Research Database (Denmark)

    Conrad, Finn

    2005-01-01

    The paper presents and discusses a R&D-view on trends in development and best practise in design of both low-pressure and high-pressure tap water hydraulic components and systems for motion control as well as open-ended solutions various industrial applications. The focus is on the advantages using...... 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...

  17. Pressure Gradient Influence on MHD Flow for Generalized Burgers’ Fluid with Slip Condition

    Directory of Open Access Journals (Sweden)

    Ghada H. Ibraheem,

    2014-07-01

    Full Text Available This paper presents a research for magnetohydrodynamic (MHD flow of an incompressible generalized Burgers' fluid including by an accelerating plate and flowing under the action of pressure gradient. Where the no – slip assumption between the wall and the fluid is no longer valid. The fractional calculus approach is introduced to establish the constitutive relationship of the generalized Burgers' fluid. By using the discrete Laplace transform of the sequential fractional derivatives, a closed form solutions for the velocity and shear stress are obtained in terms of Fox H- function for the following two problems: (i flow due to a constant pressure gradient, and (ii flow due to due to a sinusoidal pressure gradient. The solutions for no – slip condition and no magnetic field, can be derived as special cases of our solutions. Furthermore, the effects of various parameters on the velocity distribution characteristics are analyzed and discussed in detail. Comparison between the two cases is also made.

  18. Pulse pressure variation to predict fluid responsiveness in spontaneously breathing patients: tidal vs. forced inspiratory breathing.

    Science.gov (United States)

    Hong, D M; Lee, J M; Seo, J H; Min, J J; Jeon, Y; Bahk, J H

    2014-07-01

    We evaluated whether pulse pressure variation can predict fluid responsiveness in spontaneously breathing patients. Fifty-nine elective thoracic surgical patients were studied before induction of general anaesthesia. After volume expansion with hydroxyethyl starch 6 ml.kg(-1) , patients were defined as responders by a ≥ 15% increase in the cardiac index. Haemodynamic variables were measured before and after volume expansion and pulse pressure variations were calculated during tidal breathing and during forced inspiratory breathing. Median (IQR [range]) pulse pressure variation during forced inspiratory breathing was significantly higher in responders (n = 29) than in non-responders (n = 30) before volume expansion (18.2 (IQR 14.7-18.2 [9.3-31.3])% vs. 10.1 (IQR 8.3-12.6 [4.8-21.1])%, respectively, p breathing could predict fluid responsiveness (area under the curve 0.910, p breathing can be used to guide fluid management in spontaneously breathing patients.

  19. MEASUREMENT AND PREDICTION OF VOLUMETRIC AND TRANSPORT PROPERTIES OF RESERVOIR FLUIDS AT HIGH PRESSURE

    OpenAIRE

    Ungerer, Philippe; Batut, C.; Moracchini, G.; Sanchez, J.; Sant'ana,H. B.; Carrier, J; Jensen, D. M.

    1998-01-01

    International audience; Discoveries of oil and gas fields under severe conditions of temperature (above 150¡C) or pressure (in excess of 50 MPa) have been made in various regions of the world. In the North Sea, production is scheduled from deep reservoirs at 190¡ C and 110 MPa. This brings with it important challenges for predicting the properties of reservoir fluids, both from an experimental and a theoretical standpoint. In order to perform fluid studies for these reservoir conditions, IFP ...

  20. Fluid pressures at the shoe-floor-contaminant interface during slips: effects of tread and implications on slip severity.

    Science.gov (United States)

    Beschorner, Kurt E; Albert, Devon L; Chambers, April J; Redfern, Mark S

    2014-01-22

    Previous research on slip and fall accidents has suggested that pressurized fluid between the shoe and floor is responsible for initiating slips yet this effect has not been verified experimentally. This study aimed to (1) measure hydrodynamic pressures during slipping for treaded and untreaded conditions; (2) determine the effects of fluid pressure on slip severity; and (3) quantify how fluid pressures vary with instantaneous resultant slipping speed, position on the shoe surface, and throughout the progression of the slip. Eighteen subjects walked on known dry and unexpected slippery floors, while wearing treaded and untreaded shoes. Fluid pressure sensors, embedded in the floor, recorded hydrodynamic pressures during slipping. The maximum fluid pressures (mean+/-standard deviation) were significantly higher for the untreaded conditions (124+/-75 kPa) than the treaded conditions (1.1+/-0.29 kPa). Maximum fluid pressures were positively correlated with peak slipping speed (r=0.87), suggesting that higher fluid pressures, which are associated with untreaded conditions, resulted in more severe slips. Instantaneous resultant slipping speed and position of sensor relative to the shoe sole and walking direction explained 41% of the fluid pressure variability. Fluid pressures were primarily observed for untreaded conditions. This study confirms that fluid pressures are relevant to slipping events, consistent with fluid dynamics theory (i.e. the Reynolds equation), and can be modified with shoe tread design. The results suggest that the occurrence and severity of unexpected slips can be reduced by designing shoes/floors that reduce underfoot fluid pressures. © 2013 Published by Elsevier Ltd.

  1. Analysis of 6-year fluid electric conductivity logs to evaluate the hydraulic structure of the deep drill hole at Outokumpu, Finland

    Science.gov (United States)

    Sharma, Prabhakar; Tsang, Chin-Fu; Kukkonen, Ilmo T.; Niemi, Auli

    2016-07-01

    Over the last two decades, the flowing fluid electric conductivity (FFEC) logging method has been applied in boreholes in the well-testing mode to evaluate the transmissivity, hydraulic head, and formation water electrical conductivity as a function of depth with a resolution of about 10-20 cm. FFEC profiles along the borehole are obtained under both shut-in and pumping conditions in a logging procedure that lasts only 3 or 4 days. A method for analyzing these FFEC logs has been developed and successfully employed to obtain formation parameters in a number of field studies. The present paper concerns the analysis of a unique set of FFEC logs that were taken from a deep borehole reaching down to 2.5 km at Outokumpu, Finland, over a 6-year time period. The borehole intersects paleoproterozoic metasedimentary, granitoid, and ophiolite-derived rocks. After the well was drilled, completed, and cleaned up, FFEC logs were obtained after 7, 433, 597, 948, and 2036 days. In analyzing these five profiles, we discovered the need to account for salinity diffusion from water in the formation to the borehole. Analysis results include the identification of 15 hydraulically conducting zones along the borehole, the calculation of flow rates associated with these 15 zones, as well as the estimation of the variation of formation water electrical conductivity as a function of depth. The calculated flow rates were used to obtain the tentative hydraulic conductivity values at these 15 depth levels.

  2. In-situ Stresses, Pore-fluid Pressures and Uplift Erosion in Relation to Active Thrust Faulting in western Taiwan

    Science.gov (United States)

    Hung, J.; Yen, P.; Wang, L.

    2012-12-01

    We have studied the in-situ stresses, pore-fluid pressures and amounts of uplift erosion (UE) from petroleum wells drilled in the Hsinchu-Taichung area of western Taiwan Fold-thrust Belt. The average gradient of regional vertical stress (Sv) calculated from formation density logs is about 23 MPa/km. The magnitude of pore pressure (Pp) is estimated from mud pressure, gas cut and repeat formation test (RFT) in reservoir sandstone, and sonic logs. P-wave travel time in shale (STT) is used to determine the fluid-retention depth (ZFRD) which defines current fully compacted sediments with hydrostatic pressures above and undercompacted, overpressured zones below. Regional ZFRD is ~ 3 km except in the Chuhuangkeng anticline, where ZFRD is at shallower depth (~ 2.2 km) and extremely high pore pressure (λ=0.8) is also observed.. Calculated amounts of UE increase from 0.6 to 4.6 km eastward from outer to inner Foothills belt and correspond to stratigraphy downward and depth upward migration of the ZFRD. Along-strike variation of UE is insignificant. Hydraulic fracturing data including leak-off tests (LOTs) and mini-fracs, as well as qualitative data such as mud loss, are used to constrain the minimum horizontal stress (Shmin). The linear gradient of Shmin is about 17~19 MPa/km, relatively less than that of Sv (~23.60 MPa/km). This implies the in-situ stresses are at strike-slip (SHmax>SV>Shmin) to reverse fault considering focal mechanisms of seismicity are dominant by these two stress regimes in the study area. An upper-bound value of the maximum horizontal stress (SHmax) constrained by frictional limits and the coefficient of friction (μ=0.6) can be estimated from Anderson (1951) faulting criterion. Caliper logs from 8 wells are used to calculate the orientations of the maximum horizontal stresses following the definitions of borehole breakout in World Stress Map. The maximum horizontal stress axis is oriented in NW-SE but local variations occur when passing through

  3. Characteristics and performance analysis report of the major thermal hydraulic components in the high temperature/high pressure thermal hydraulic test facility (VISTA)

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Ki Yong; Park, Hyun Sik; Cho, Seok; Lee, Sung Jae; Song, Chul Hwa; Park, Chun Kyong; Chung, Moon Ki

    2003-12-01

    The VISTA (Experimental Verification by Integral Simulation of Transients and Accidents) is an experimental facility to verify the performance and safety issues of the SMART-P (Pilot plant of the System-integrated Modular Advanced Reactor). The basic design of the SMART-P has been completed by KAERI. The present report describes the characteristics and performance of the major thermal hydraulic components in the VISTA Facility.

  4. Advanced fluid modelling and PIC/MCC simulations of low-pressure ccrf discharges

    CERN Document Server

    Becker, Markus M; Sun, Anbang; Bonitz, Michael; Loffhagen, Detlef

    2016-01-01

    Comparative studies of capacitively coupled radio-frequency discharges in helium and argon at pressures between 10 and 80 Pa are presented applying two different fluid modelling approaches as well as two independently developed particle-in-cell/Monte Carlo collision (PIC/MCC) codes. The focus is on the analysis of the range of applicability of a recently proposed fluid model including an improved drift-diffusion approximation for the electron component as well as its comparison with fluid modelling results using the classical drift-diffusion approximation and benchmark results obtained by PIC/MCC simulations. Main features of this time- and space-dependent fluid model are given. It is found that the novel approach shows generally quite good agreement with the macroscopic properties derived by the kinetic simulations and is largely able to characterize qualitatively and quantitatively the discharge behaviour even at conditions when the classical fluid modelling approach fails. Furthermore, the excellent agreem...

  5. Intimal and medial contributions to the hydraulic resistance of the arterial wall at different pressures: a combined computational and experimental study.

    Science.gov (United States)

    Chooi, K Y; Comerford, A; Sherwin, S J; Weinberg, P D

    2016-06-01

    The hydraulic resistances of the intima and media determine water flux and the advection of macromolecules into and across the arterial wall. Despite several experimental and computational studies, these transport processes and their dependence on transmural pressure remain incompletely understood. Here, we use a combination of experimental and computational methods to ascertain how the hydraulic permeability of the rat abdominal aorta depends on these two layers and how it is affected by structural rearrangement of the media under pressure. Ex vivo experiments determined the conductance of the whole wall, the thickness of the media and the geometry of medial smooth muscle cells (SMCs) and extracellular matrix (ECM). Numerical methods were used to compute water flux through the media. Intimal values were obtained by subtraction. A mechanism was identified that modulates pressure-induced changes in medial transport properties: compaction of the ECM leading to spatial reorganization of SMCs. This is summarized in an empirical constitutive law for permeability and volumetric strain. It led to the physiologically interesting observation that, as a consequence of the changes in medial microstructure, the relative contributions of the intima and media to the hydraulic resistance of the wall depend on the applied pressure; medial resistance dominated at pressures above approximately 93 mmHg in this vessel.

  6. A solid-fluid mixture model allowing for solid dilatation under external pressure

    CERN Document Server

    Sciarra, Giulio; Hutter, Kolumban

    2010-01-01

    A sponge subjected to an increase of the outside fluid pressure expands its volume but nearly mantains its true density and thus gives way to an increase of the interstitial volume. This behaviour, not yet properly described by solid-fluid mixture theories, is studied here by using the Principle of Virtual Power with the most simple dependence of the free energy as a function of the partial apparent densities of the solid and the fluid. The model is capable of accounting for the above mentioned dilatational behaviour, but in order to isolate its essential features more clearly we compromise on the other aspects of deformation.

  7. Thermal fluid mixing behavior during medium break LOCA in evaluation of pressurized thermal shock

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jae Won; Bang, Young Seok; Seul, Kwang Won; Kim, Hho Jung [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1998-12-31

    Thermal fluid mixing behavior during a postulated medium-size hot leg break loss of coolant accident is analyzed for the international comparative assessment study on pressurized thermal shock (PTS-ICAS) proposed by OECD-NEA. The applicability of RELAP5 code to analyze the thermal fluid mixing behavior is evaluated through a simple modeling relevant to the problem constraints. Based on the calculation result, the onset of thermal stratification is investigated using Theofanous`s empirical correlation. Sensitivity calculations using a fine node model and crossflow model are also performed to evaluate the modeling capability on multi-dimensional characteristics related to thermal fluid mixing. 6 refs., 8 figs. (Author)

  8. Determining Pressure with Daughter Minerals in Fluid Inclusion by Raman Spectroscopy:Sphalerite as an Example

    Institute of Scientific and Technical Information of China (English)

    YANG Yuping; ZHENG Haifei; ZHANG Lifei

    2009-01-01

    Raman frequency of some materials,including minerals.molecules and ions, shifts systematically with changing pressure and temperature.This property is often used as a pressure gauge in high pressure experiments with the hydrothermal diamond anvil cell(HDAC).Since the system of fluid inclusion is similar to that of HDAC,it can also be used to determine the internal pressure of fluid inclusions.Sphalerite is a common daughter mineral.In this study,the frequency shift of the 350 cm-1 peak of sphalerite has been studied from 296 to 523 K and from 0.07 to 2.00 GPa using the HDAC.The global slope of the isotherms(σV30/σp)T is 0.0048 in the studied pressure range. No significant variation of the slopes with temperature has been observed.The correlation between the frequency shift of the 350 cm-1 peak of sphalerite and pressure and temperature is constrained as P=208.33(△Vp)350+3.13T-943.75.This relationship may be used to estimate the internal pressure of the sphalerite-bearing fluid inclusions.

  9. Effect of fluid/structure-interaction on pressure pulse loads on pipes

    Energy Technology Data Exchange (ETDEWEB)

    Kellner, A.; Schoenfelder, C.

    1982-08-01

    In the analysis of pressure pulse loads on piping systems the fluid-structure-interaction is usually neglected. The resulting violation of energy conservation can lead to drastic overestimations of the loads. At first simple formulas are derived which can be used for a rough assessment of the magnitude of this effect for both possible forms of loads due to pressure waves: pipe wall stress and excitation of global pipe vibration. Secondly numerical methods which explicitly include the fluid-structure-interaction are described and some computational results presented.

  10. Microfluidic parallel circuit for measurement of hydraulic resistance.

    Science.gov (United States)

    Choi, Sungyoung; Lee, Myung Gwon; Park, Je-Kyun

    2010-08-31

    We present a microfluidic parallel circuit that directly compares the test channel of an unknown hydraulic resistance with the reference channel with a known resistance, thereby measuring the unknown resistance without any measurement setup, such as standard pressure gauges. Many of microfluidic applications require the precise transport of fluid along a channel network with complex patterns. Therefore, it is important to accurately characterize and measure the hydraulic resistance of each channel segment, and determines whether the device principle works well. However, there is no fluidic device that includes features, such as the ability to diagnose microfluidic problems by measuring the hydraulic resistance of a microfluidic component in microscales. To address the above need, we demonstrate a simple strategy to measure an unknown hydraulic resistance, by characterizing the hydraulic resistance of microchannels with different widths and defining an equivalent linear channel of a microchannel with repeated patterns of a sudden contraction and expansion.

  11. Kitchen Physics: Lessons in Fluid Pressure and Error Analysis

    Science.gov (United States)

    Vieyra, Rebecca Elizabeth; Vieyra, Chrystian; Macchia, Stefano

    2017-02-01

    Although the advent and popularization of the "flipped classroom" tends to center around at-home video lectures, teachers are increasingly turning to at-home labs for enhanced student engagement. This paper describes two simple at-home experiments that can be accomplished in the kitchen. The first experiment analyzes the density of four liquids using a waterproof case and a smartphone barometer in a container, sink, or tub. The second experiment determines the relationship between pressure and temperature of an ideal gas in a constant volume container placed momentarily in a refrigerator freezer. These experiences provide a ripe opportunity both for learning fundamental physics concepts as well as to investigate a variety of error analysis techniques that are frequently overlooked in introductory physics courses.

  12. Mounting Pressure in the Microenvironment: Fluids, Solids, and Cells in Pancreatic Ductal Adenocarcinoma.

    Science.gov (United States)

    DuFort, Christopher C; DelGiorno, Kathleen E; Hingorani, Sunil R

    2016-06-01

    The microenvironment influences the pathogenesis of solid tumors and plays an outsized role in some. Our understanding of the stromal response to cancers, particularly pancreatic ductal adenocarcinoma, has evolved from that of host defense to tumor offense. We know that most, although not all, of the factors and processes in the microenvironment support tumor epithelial cells. This reappraisal of the roles of stromal elements has also revealed potential vulnerabilities and therapeutic opportunities to exploit. The high concentration in the stroma of the glycosaminoglycan hyaluronan, together with the large gel-fluid phase and pressures it generates, were recently identified as primary sources of treatment resistance in pancreas cancer. Whereas the relatively minor role of free interstitial fluid in the fluid mechanics and perfusion of tumors has been long appreciated, the less mobile, gel-fluid phase has been largely ignored for historical and technical reasons. The inability of classic methods of fluid pressure measurement to capture the gel-fluid phase, together with a dependence on xenograft and allograft systems that inaccurately model tumor vascular biology, has led to an undue emphasis on the role of free fluid in impeding perfusion and drug delivery and an almost complete oversight of the predominant role of the gel-fluid phase. We propose that a hyaluronan-rich, relatively immobile gel-fluid phase induces vascular collapse and hypoperfusion as a primary mechanism of treatment resistance in pancreas cancers. Similar properties may be operant in other solid tumors as well, so revisiting and characterizing fluid mechanics with modern techniques in other autochthonous cancers may be warranted.

  13. Dry and hydraulic extensile fracturing of porous impermeable materials

    NARCIS (Netherlands)

    Visser, J.H.M.; Van Mier, J.C.M.

    1996-01-01

    Extensile hydraulic fracturing of mortar is investigated and compared to extensile dry fracturing of sandstone. The extensile fracture experiments have been performed in a Hookean cell in deformation control. The cell allows for axial loading and radial fluid pressure loading of cylindrical specimen

  14. (N+2)-Dimensional Anisotropic Charged Fluid Spheres with Pressure: Riccati Equation

    CERN Document Server

    Bijalwan, Naveen

    2011-01-01

    General exact (N+2)-dimensional,n>=2 solutions in general theory of relativity of Einstein-Maxwell field equations for static anisotropic spherically symmetric distribution of charged fluid are expressed in terms of radial pressure. Subsequently, metrics (e(lambda) and e(nu)), matter density and electric intensity are expressible in terms of pressure. We extend the methodology used by Bijalwan (2011a, 2011c, 2011d) for charged and anisotropic fluid. Consequently, radial pressure is found to be an invertible arbitrary function of w(c1+c2r^2), where c1 and c2(non zero) are arbitrary constants, and r is the radius of star, i.e. p=p(w) . We present a general solution for static anisotropic charged pressure fluid in terms for w. We reduce to the problem of finding solutions to anisotropic charged fluid to that of finding solutions to a Riccati equation. Also, these solutions satisfy barotropic equation of state relating the radial pressure to the energy density.

  15. Measurement of the Density of Base Fluids at Pressures 0.422 to 2.20 Gpa

    Science.gov (United States)

    Hamrock, B. J.; Jacobson, B. O.; Bergstroem, S. I.

    1985-01-01

    The influence of pressure on the density of six base fluids is experimentally studied for a range of pressures from 0.422 to 2.20 GPa. An important parameter used to describe the results is the change in relative volume with change in pressure dv sub r/dp. For pressures less than the solidification pressure (p ps) a small change in pressure results in a large change in dv sub r/ps. For pressures greater than the solidification pressure (p ps) there is no change in dv sub r/dp with changing pressure. The solidification pressures of the base fluids varies considerably, as do the slopes that the experimental data assumes for p ps. A new formula is developed that describes the effect of pressure on density in terms of four constants. These constants vary for the different base fluids tested.

  16. Valve inlet fluid conditions for pressurizer safety and relief valves in combustion engineering-designed plants. Final report. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Bahr, J.; Chari, D.; Puchir, M.; Weismantel, S.

    1982-12-01

    The purpose of this study is to assemble documented information for C-E designed plants concerning pressurizer safety and power operated relief valve (PROV) inlet fluid conditions during actuation as calculated by conventional licensing analyses. This information is to be used to assist in the justification of the valve inlet fluid conditions selected for the testing of safety valves and PORVs in the EPRI/PWR Safety/Relief Valve Test Program. Available FSAR/Reload analyses and certain low temperature overpressurization analyses were reviewed to identify the pressurization transients which would actuate the valves, and the corresponding valve inlet fluid conditions. In addition, consideration was given to the Extended High Pressure Liquid Injection event. A general description of each pressurization transient is provided. The specific fluid conditions identified and tabulated for each C-E designed plant for each transient are peak pressurizer pressure, pressure ramp rate at actuation, temperature and fluid state.

  17. Energy Cost of Avoiding Pressure Oscillations in a Discrete Fluid Power Force System

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

    2015-01-01

    In secondary valve controlled discrete fluid power force systems the valve opening trajectory greatly influences the pressure dynamics in the actuator chambers. For discrete fluid power systems featuring hoses of significant length pressure oscillations due to fast valve switching is well...... converters. Further the energy losses introduced during the shifting period is investigated and compared for two valve opening algorithms. The investigation of the energy loss is utilised to quantify the importance of a fast valve switching and the energy cost of reducing pressure oscillations. The paper...... will present measurements comparing pressure dynamics for two valve opening algorithms. In addition the paper will give a theoretical investigation of the energy loss during valve shifting and finally measurements of average power output from the power take-off system in various sea states are compared...

  18. Experimental and Parametric Design of Petroleum Back-pressured Hydraulic Impactor

    Institute of Scientific and Technical Information of China (English)

    YUAN Guang-jie; YAO Zhen-qiang; CHEN Ping; HUANG Wan-zhi

    2005-01-01

    Percussive-rotary drilling technology was considered many years ago as one of the best approaches for hard rock drilling. It is a key for popularizing this technology on a large scale to design and make an impactor with excellent performance. This paper presents a suit of method to design the percussive parameters for the oil or gas field by introducing the working principle of back-pressured impactor, dividing the working periods of impactor into three phases and establishing the computer emulational model of percussive parameters. It draws a comparison between the results of model calculation and experiment on the basis of analyzing the experiment results of impactor.The conclude provides credible foundation for designing and further ameliorating the impactor.

  19. Pulse pressure variation and prediction of fluid responsiveness in patients ventilated with low tidal volumes

    Directory of Open Access Journals (Sweden)

    Clarice Daniele Alves de Oliveira-Costa

    2012-07-01

    Full Text Available OBJECTIVE: To determine the utility of pulse pressure variation (ΔRESP PP in predicting fluid responsiveness in patients ventilated with low tidal volumes (V T and to investigate whether a lower ΔRESP PP cut-off value should be used when patients are ventilated with low tidal volumes. METHOD: This cross-sectional observational study included 37 critically ill patients with acute circulatory failure who required fluid challenge. The patients were sedated and mechanically ventilated with a V T of 6-7 ml/kg ideal body weight, which was monitored with a pulmonary artery catheter and an arterial line. The mechanical ventilation and hemodynamic parameters, including ΔRESP PP, were measured before and after fluid challenge with 1,000 ml crystalloids or 500 ml colloids. Fluid responsiveness was defined as an increase in the cardiac index of at least 15%. ClinicalTrial.gov: NCT01569308. RESULTS: A total of 17 patients were classified as responders. Analysis of the area under the ROC curve (AUC showed that the optimal cut-off point for ΔRESP PP to predict fluid responsiveness was 10% (AUC = 0.74. Adjustment of the ΔRESP PP to account for driving pressure did not improve the accuracy (AUC = 0.76. A ΔRESP PP>10% was a better predictor of fluid responsiveness than central venous pressure (AUC = 0.57 or pulmonary wedge pressure (AUC = 051. Of the 37 patients, 25 were in septic shock. The AUC for ΔRESP PP>10% to predict responsiveness in patients with septic shock was 0.484 (sensitivity, 78%; specificity, 93%. CONCLUSION: The parameter D RESP PP has limited value in predicting fluid responsiveness in patients who are ventilated with low tidal volumes, but a ΔRESP PP>10% is a significant improvement over static parameters. A ΔRESP PP > 10% may be particularly useful for identifying responders in patients with septic shock.

  20. The role of fluid pressure in frictional stability and earthquake triggering: insights from laboratory experiments

    Science.gov (United States)

    Collettini, Cristiano; Scuderi, Marco

    2015-04-01

    Fluid overpressure has been proposed as one of the primary mechanisms that facilitate earthquake slip along faults. However, elastic dislocation theory combined with friction laws suggests that fluid overpressure may inhibit the dynamic instabilities that result in earthquakes, by controlling the critical fault stiffness (kc). This controversy poses a serious problem in our understanding of earthquake physics, with severe implications for both natural and human-induced seismic hazard. Nevertheless, currently, there are no systematic studies on the role of fluid pressure under controlled, laboratory conditions for which the evolution of friction parameters and slip stability can be measured. We have used a state-of-the-art biaxial rock deformation apparatus within a pressure vessel, in order to allow a true triaxial stress field, in a double direct shear configuration. We tested carbonate fault gouge, Carrara marble, sieved to a grain size of 125 μm. Normal stresses and confining pressure were held constant throughout the experiment at values of 5 to 40 MPa, and the pore fluid pressure was varied from hydrostatic up to near lithostatic values. Shear stress was induced by a constant displacement rate and sliding velocities varied from 0.1-1000 μm/s, in order to evaluate slip stability via rate- and state- dependent frictional parameters, such as (a-b), Dc and kc. Our data show that sliding velocity controls the values of friction parameters. In addition we observe a general increase of (a-b) and a decrease of Dc with increasing fluid pressure. Our observations suggest that fluid overpressure does not only facilitate fault reactivation but it also influences frictional parameters with important implications for fault stability and earthquake triggering.

  1. Modeling seismic stimulation: Enhanced non-aqueous fluid extraction from saturated porous media under pore-pressure pulsing at low frequencies

    Science.gov (United States)

    Lo, Wei-Cheng; Sposito, Garrison; Huang, Yu-Han

    2012-03-01

    Seismic stimulation, the application of low-frequency stress-pulsing to the boundary of a porous medium containing water and a non-aqueous fluid to enhance the removal of the latter, shows great promise for both contaminated groundwater remediation and enhanced oil recovery, but theory to elucidate the underlying mechanisms lag significantly behind the progress achieved in experimental research. We address this conceptual lacuna by formulating a boundary-value problem to describe pore-pressure pulsing at seismic frequencies that is based on the continuum theory of poroelasticity for an elastic porous medium permeated by two immiscible fluids. An exact analytical solution is presented that is applied numerically using elasticity parameters and hydraulic data relevant to recent proof-of-principle laboratory experiments investigating the stimulation-induced mobilization of trichloroethene (TCE) in water flowing through a compressed sand core. The numerical results indicated that significant stimulation-induced increases of the TCE concentration in effluent can be expected from pore-pressure pulsing in the frequency range of 25-100 Hz, which is in good agreement with what was observed in the laboratory experiments. Sensitivity analysis of our numerical results revealed that the TCE concentration in the effluent increases with the porous medium framework compressibility and the pulsing pressure. Increasing compressibility also leads to an optimal stimulation response at lower frequencies, whereas changing the pulsing pressure does not affect the optimal stimulation frequency. Within the context of our model, the dominant physical cause for enhancement of non-aqueous fluid mobility by seismic stimulation is the dilatory motion of the porous medium in which the solid and fluid phases undergo opposite displacements, resulting in stress-induced changes of the pore volume.

  2. 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.

  3. COMPUTATIONAL FLUID DYNAMICS RESEARCH ON PRESSURE LOSS OF CROSS-FLOW PERFORATED MUFFLER

    Institute of Scientific and Technical Information of China (English)

    HU Xiaodong; ZHOU Yiqi; FANG Jianhua; MAN Xiliang; ZHAO Zhengxu

    2007-01-01

    The pressure loss of cross-flow perforated muffler has been computed with the procedure of physical modeling, simulation and data processing. Three-dimensional computational fluid dynamics (CFD) has been used to investigate the relations of porosities, flow velocity and diameter of the holes with the pressure loss. Accordingly, some preliminary results have been obtained that pressure loss increases with porosity descent as nearly a hyperbolic trend, rising flow velocity of the input makes the pressure loss increasing with parabola trend, diameter of holes affects little about pressure loss of the muffler. Otherwise, the holes on the perforated pipes make the air flow gently and meanly,which decreases the air impact to the wall and pipes in the muffler. A practical perforated muffler is used to illustrate the available of this method for pressure loss computation, and the comparison shows that the computation results with the method of CFD has reference value for muffler design.

  4. 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.

  5. Role of Fluid Pressure in the Production Behavior of EnhancedGeothermal Systems with CO2 as Working Fluid

    Energy Technology Data Exchange (ETDEWEB)

    Pruess, Karsten

    2007-04-13

    Numerical simulation is used to evaluate mass flow and heatextraction rates from enhanced geothermal injection-production systemsthat are operated using either CO2 or water as heat transmission fluid.For a model system patterned after the European hot dry rock experimentat Soultz, we find significantly greater heat extraction rates for CO2 ascompared to water. The strong dependence of CO2 mobility (=density/viscosity) upon temperature and pressure may lead to unusualproduction behavior, where heat extraction rates can actually increasefor a time, even as the reservoir is subject to thermaldepletion.

  6. Fluid pressure responses for a Devil's Slide-like system: problem formulation and simulation

    Science.gov (United States)

    Thomas, Matthew A.; Loague, Keith; Voss, Clifford I.

    2015-01-01

    This study employs a hydrogeologic simulation approach to investigate subsurface fluid pressures for a landslide-prone section of the central California, USA, coast known as Devil's Slide. Understanding the relative changes in subsurface fluid pressures is important for systems, such as Devil's Slide, where slope creep can be interrupted by episodic slip events. Surface mapping, exploratory core, tunnel excavation records, and dip meter data were leveraged to conceptualize the parameter space for three-dimensional (3D) Devil's Slide-like simulations. Field observations (i.e. seepage meter, water retention, and infiltration experiments; well records; and piezometric data) and groundwater flow simulation (i.e. one-dimensional vertical, transient, and variably saturated) were used to design the boundary conditions for 3D Devil's Slide-like problems. Twenty-four simulations of steady-state saturated subsurface flow were conducted in a concept-development mode. Recharge, heterogeneity, and anisotropy are shown to increase fluid pressures for failure-prone locations by up to 18.1, 4.5, and 1.8% respectively. Previous estimates of slope stability, driven by simple water balances, are significantly improved upon with the fluid pressures reported here. The results, for a Devil's Slide-like system, provide a foundation for future investigations

  7. Early effects of combretastatin-A4 disodium phosphate on tumor perfusion and interstitial fluid pressure

    DEFF Research Database (Denmark)

    Ley, C.D.; Horsman, Michael Robert; Kristjansen, P.E.G.

    2007-01-01

    of the tumor vasculature. It has been proposed that increased permeability causes a transient increase in interstitial fluid pressure (IFP), which in turn could collapse intratumoral blood vessels. We examined the immediate effects of CA4DP on tumor IFP in C3H mammary carcinoma. Mice were treated with 100 mg...

  8. A thermodynamically consistent model for granular-fluid mixtures considering pore pressure evolution and hypoplastic behavior

    Science.gov (United States)

    Hess, Julian; Wang, Yongqi

    2016-11-01

    A new mixture model for granular-fluid flows, which is thermodynamically consistent with the entropy principle, is presented. The extra pore pressure described by a pressure diffusion equation and the hypoplastic material behavior obeying a transport equation are taken into account. The model is applied to granular-fluid flows, using a closing assumption in conjunction with the dynamic fluid pressure to describe the pressure-like residual unknowns, hereby overcoming previous uncertainties in the modeling process. Besides the thermodynamically consistent modeling, numerical simulations are carried out and demonstrate physically reasonable results, including simple shear flow in order to investigate the vertical distribution of the physical quantities, and a mixture flow down an inclined plane by means of the depth-integrated model. Results presented give insight in the ability of the deduced model to capture the key characteristics of granular-fluid flows. We acknowledge the support of the Deutsche Forschungsgemeinschaft (DFG) for this work within the Project Number WA 2610/3-1.

  9. Viscoelastic fluid flow in circular narrow confinements driven by periodic pressure and potential gradients

    NARCIS (Netherlands)

    Nguyen, T.; Berg, van den A.; Eijkel, J.C.T.

    2015-01-01

    We present an in-depth analysis and analytical solution for AC hydrodynamic flow (driven by a timedependent pressure gradient and/or electric fields) of viscoelastic fluid through cylindrical micro-, nanochannels. Particularly, for this purpose we solve the linearized Poisson-Boltzmann equation tog

  10. Cerebrospinal fluid flow and production in patients with normal pressure hydrocephalus studied by MRI

    DEFF Research Database (Denmark)

    Gideon, P; Ståhlberg, F; Thomsen, C

    1994-01-01

    An interleaved velocity-sensitised fast low-angle shot pulse sequence was used to study cerebrospinal fluid (CSF) flow in the cerebral aqueduct, and supratentorial CSF production in 9 patients with normal pressure hydrocephalus (NPH) and 9 healthy volunteers. The peak aqueduct CSF flow, both caudal...

  11. FRACTURING FLUID CHARACTERIZATION FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    Subhash Shah

    2000-08-01

    Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.

  12. Universal scaling law for energy and pressure in a shearing fluid.

    Science.gov (United States)

    Desgranges, Caroline; Delhommelle, Jerome

    2009-05-01

    Using nonequilibrium molecular-dynamics simulation, we study the shear-rate dependence of pressure and potential energy in a liquid metal subjected to shear. We show that both thermodynamic properties vary according to a power law gamma[over ];{beta} of the shear rate gamma[over ] , in which the exponent beta is a simple linear function of temperature and density. Moreover, we establish that the coefficients for this linear law are the same as those previously obtained for a Lennard-Jones fluid by Ge [Phys. Rev. E 67, 061201 (2003)]. This is a strong indication that these coefficients, as well as the linear law for beta , could be applicable to any atomic fluid. It is also an important step toward the determination of a nonequilibrium equation of state, which would predict the value of pressure and energy of a shearing fluid for any state point and any value of the applied shear rate.

  13. X-ray Compton scattering experiments for fluid alkali metals at high temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, K., E-mail: kazuhiro-matsuda@scphys.kyoto-u.ac.jp; Fukumaru, T.; Kimura, K.; Yao, M. [Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Tamura, K. [Graduate School of Engineering, Kyoto University, Kyoto 606-8502 (Japan); Katoh, M. [A.L.M.T. Corp., Iwasekoshi-Machi 2, Toyama 931-8543 (Japan); Kajihara, Y.; Inui, M. [Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521 (Japan); Itou, M.; Sakurai, Y. [Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2015-08-17

    We have developed a high-pressure vessel and a cell for x-ray Compton scattering measurements of fluid alkali metals. Measurements have been successfully carried out for alkali metal rubidium at elevated temperatures and pressures using synchrotron radiation at SPring-8. The width of Compton profiles (CPs) of fluid rubidium becomes narrow with decreasing fluid density, which indicates that the CPs sensitively detect the effect of reduction in the valence electron density. At the request of all authors of the paper, and with the agreement of the Proceedings Editor, an updated version of this article was published on 10 September 2015. The original article supplied to AIP Publishing was not the final version and contained PDF conversion errors in Formulas (1) and (2). The errors have been corrected in the updated and re-published article.

  14. Geometry of elastic hydrofracturing by injection of an over pressured non-Newtonian Fluid

    CERN Document Server

    Cerca, Mariano; Barrientos, Bernardino; Soto, Enrique; Mares, Carlos

    2009-01-01

    The nucleation and propagation of hydrofractures by injection of over pressured fluids in an elastic and isotropic medium are studied experimentally. Non-Newtonian fluids are injected inside a gelatine whose mechanical properties are assumed isotropic at the experimental strain rates. Linear elastic theory predicts that plastic deformation associated to breakage of gelatin bonds is limited to a small zone ahead of the tip of the propagating fracture and that propagation will be maintained while the fluid pressure exceeds the normal stress to the fracture walls (Ch\\'avez-\\'Alvarez,2008) (i.e., the minimum compressive stress), resulting in a single mode I fracture geometry. However, we observed the propagation of fractures type II and III as well as nucleation of secondary fractures, with oblique to perpendicular trajectories with respect to the initial fracture. In the Video (http://hdl.handle.net/1813/14122) experimental evidence shows that the fracture shape depends on the viscoelastic properties of gelatine...

  15. Pressure tensor dynamics in the fluid description of Weibel-type instabilities

    Science.gov (United States)

    Sarrat, Mathieu; Del Sarto, Daniele; Ghizzo, Alain

    2016-10-01

    The study of Weibel-type instabilities triggered by temperature or momentum anisotropy normally requires a full kinetic treatement, though reduced kinetic models often provide an efficient alternative, both from a computational point of view and thanks to a simplified analysis that helps a better physical insight. We here show how, similarly to reduced kinetic models, an extended fluid model including the full pressure tensor dynamics provides a consistent description of Weibel-type modes in presence of two counterstreaming, non-relativistic beams with initially anisotropic pressures: focussing on propagation transverse and parallel to the beams we discuss the fluid dispersion relation of Weibel Instability-Current Filamentation Instability coupled modes and of the time resonant Weibel instability. This fluid analysis is shown to agree with the kinetic result and to allow the identification of some thermal effects, whose interpretation appeared more difficult in full kinetic descriptions.

  16. Relative value of pressures and volumes in assessing fluid responsiveness after valvular and coronary artery surgery.

    Science.gov (United States)

    Breukers, Rose-Marieke B G E; Trof, Ronald J; de Wilde, Rob B P; van den Berg, Paul C M; Twisk, Jos W R; Jansen, Jos R C; Groeneveld, Johan

    2009-01-01

    Cardiac function may differ after valvular (VS) and coronary artery (CAS) surgery and this may affect assessment of fluid responsiveness. The aim of the study was to compare VS and CAS in the value of cardiac filling pressures and volumes herein. There were eight consecutive patients after VS and eight after CAS, with femoral and pulmonary artery catheters in place. In each patient, five sequential fluid loading steps of 250 ml of colloid each were done. We measured central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP) and, by transpulmonary thermodilution, cardiac index (CI) and global end-diastolic (GEDVI) and intrathoracic blood volume (ITBVI) indices. Fluid responsiveness was defined by a CI increase >5% or >10% per step. Global ejection fraction was lower and PAOP was higher after VS than CAS. In responding steps after VS (n=9-14) PAOP and volumes increased, while CVP and volumes increased in responding steps (n=12-19) after CAS. Baseline PAOP was lower in responding steps after VS only. Hence, baseline PAOP as well as changes in PAOP and volumes were of predictive value after VS and changes in CVP and volumes after CAS, in receiver operating characteristic curves. After VS, PAOP and volume changes equally correlated to CI changes. After CAS, only changes in CVP and volumes correlated to those in CI. While volumes are equally useful in monitoring fluid responsiveness, the predictive and monitoring value of PAOP is greater after VS than after CAS. In contrast, the CVP is of similar value as volume measurements in monitoring fluid responsiveness after CAS. The different value of pressures rather than of volumes between surgery types is likely caused by systolic left ventricular dysfunction in VS. The study suggests an effect of systolic cardiac function on optimal parameters of fluid responsiveness and superiority of the pulmonary artery catheter over transpulmonary dilution, for haemodynamic monitoring of VS patients.

  17. [Cerebrospinal fluid pressure studies after the intravenous administration of the steroid narcotic, alphaxolone + alphadolone acetate (Althesin)].

    Science.gov (United States)

    Ekhart, E; List, W F; Vadon, P; Oberbauer, R

    1979-09-30

    The effect of alphaxalon + alphadolon-acetate on cerebrospinal fluid pressure (CSFP), mean arterial blood pressure (MPA), heart rate (BMP) and blood gases was investigated in 18 patients. Cerebral perfusion pressure (CPP) was calculated from the difference MAP minus CSFP. Alphaxalon + alphadolon-acetate lowered the normal CSFP and normalized ketamin induced increase of CSFP. Premedication with alphaxalon + alphadolon-acetate delayed the ketamin induced increase of CSFP, which returned to norm after a second dose of alphaxalon + alphadolon-acetate. This effect was seen despite elevation of pCO2 in all patients breathing spontaneously.

  18. 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.

  19. Towards a non-linear theory for fluid pressure and osmosis in shales

    Science.gov (United States)

    Droghei, Riccardo; Salusti, Ettore

    2015-04-01

    In exploiting deep hydrocarbon reservoirs, often injections of fluid and/or solute are used. To control and avoid troubles as fluid and gas unexpected diffusions, a reservoir characterization can be obtained also from observations of space and time evolution of micro-earthquake clouds resulting from such injections. This is important since several among the processes caused by fluid injections can modify the deep matrix. Information about the evolution of such micro-seismicity clouds therefore plays a realistic role in the reservoir analyses. To reach a better insight about such processes, and obtain a better system control, we here analyze the initial stress necessary to originate strong non linear transients of combined fluid pressure and solute density (osmosis) in a porous matrix. All this can indeed perturb in a mild (i.e. a linear diffusion) or dramatic non linear way the rock structure, till inducing rock deformations, micro-earthquakes or fractures. I more detail we here assume first a linear Hooke law relating strain, stress, solute density and fluid pressure, and analyze their effect in the porous rock dynamics. Then we analyze its generalization, i.e. the further non linear effect of a stronger external pressure, also in presence of a trend of pressure or solute in the whole region. We moreover characterize the zones where a sudden arrival of such a front can cause micro-earthquakes or fractures. All this allows to reach a novel, more realistic insight about the control of rock evolution in presence of strong pressure fronts. We thus obtain a more efficient reservoir control to avoid large geological perturbations. It is of interest that our results are very similar to those found by Shapiro et al.(2013) with a different approach.

  20. A fast pressure-correction method for incompressible two-fluid flows

    Science.gov (United States)

    Dodd, Michael S.; Ferrante, Antonino

    2014-09-01

    We have developed a new pressure-correction method for simulating incompressible two-fluid flows with large density and viscosity ratios. The method's main advantage is that the variable coefficient Poisson equation that arises in solving the incompressible Navier-Stokes equations for two-fluid flows is reduced to a constant coefficient equation, which can be solved with an FFT-based, fast Poisson solver. This reduction is achieved by splitting the variable density pressure gradient term in the governing equations. The validity of this splitting is demonstrated from our numerical tests, and it is explained from a physical viewpoint. In this paper, the new pressure-correction method is coupled with a mass-conserving volume-of-fluid method to capture the motion of the interface between the two fluids but, in general, it could be coupled with other interface advection methods such as level-set, phase-field, or front-tracking. First, we verified the new pressure-correction method using the capillary wave test-case up to density and viscosity ratios of 10,000. Then, we validated the method by simulating the motion of a falling water droplet in air and comparing the droplet terminal velocity with an experimental value. Next, the method is shown to be second-order accurate in space and time independent of the VoF method, and it conserves mass, momentum, and kinetic energy in the inviscid limit. Also, we show that for solving the two-fluid Navier-Stokes equations, the method is 10-40 times faster than the standard pressure-correction method, which uses multigrid to solve the variable coefficient Poisson equation. Finally, we show that the method is capable of performing fully-resolved direct numerical simulation (DNS) of droplet-laden isotropic turbulence with thousands of droplets using a computational mesh of 10243 points.

  1. Rheological properties of oil-based drilling fluids at high temperature and high pressure

    Institute of Scientific and Technical Information of China (English)

    赵胜英; 鄢捷年; 舒勇; 张洪霞

    2008-01-01

    The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 ℃ using the RheoChan 7400 Rheometer.The experimental results show that the apparent viscosity,plastic viscosity and yield point decrease with the increase of temperature,and increase with the increase of pressure.The effect of pressure on the apparent viscosity,plastic viscosity and yield point is considerable at ambient temperature.However,this effect gradually reduces with the increase of temperature.The major factor influencing the rheological properties of oil-based drilling fluids is temperature instead of pressure in the deep sections of oil wells.On the basis of numerous experiments,the model for predict the apparent viscosity,plastic viscosity and yield point of oil-based drilling fluids at high temperature and pressure was established using the method of regressive analysis.It is confirmed that the calculated data are in good agreement with the measured data,and the correlation coefficients are more than 0.98.The model is convenient for use and suitable for the application in drilling operations.

  2. Pressure falloff behavior in vertically fractured wells: Non-Newtonian power-law fluids

    Energy Technology Data Exchange (ETDEWEB)

    Vongvuthipornchai, S.; Raghauan, R.; Reynolds, A.C.

    1984-09-01

    This paper examines pressure falloff behavior in fractured wells following the injection of a non-Newtonian power-law fluid. Results are presented in a form suitable for field application. Responses at wells intercepting infinite-conductivity and uniformflux fractures are considered. Procedures to identify flow regimes are discussed. The solutions presented here are new and to our knowledge not available in the literature. The consequences of neglecting the non-Newtonian characteristics of the injected fluid are examined. The results of this work were obtained by a finite difference model. Procedures to compute the apparent viscosity of power-law fluids for twodimensional flow through porous media are discussed. The formulation given here avoids numerical problems (multiple solutions, cross over, etc.) reported in other studies. Although, the main objective of the work is to examine pressure falloff behavior at fractured wells, the authors also examine responses at unfractured wells. The main objective of this part of a study is to examine the validity of using the superposition principle to analyze pressure falloff data. (The pressure distribution for this problem is governed by a nonlinear partial differential equation.) If the solutions given in the literature are used, then correction factors are needed to analyze pressure falloff data. The results of this phase of the work can also be used to analyze data in fractured wells provided that pseudoradial flow conditions exist.

  3. Trends in hydraulic fracturing distributions and treatment fluids, additives, proppants, and water volumes applied to wells drilled in the United States from 1947 through 2010: data analysis and comparison to the literature

    Science.gov (United States)

    Gallegos, Tanya J.; Varela, Brian A.

    2015-01-01

    Hydraulic fracturing is presently the primary stimulation technique for oil and gas production in low-permeability, unconventional reservoirs. Comprehensive, published, and publicly available information regarding the extent, location, and character of hydraulic fracturing in the United States is scarce. This national spatial and temporal analysis of data on nearly 1 million hydraulically fractured wells and 1.8 million fracturing treatment records from 1947 through 2010 (aggregated in Data Series 868) is used to identify hydraulic fracturing trends in drilling methods and use of proppants, treatment fluids, additives, and water in the United States. These trends are compared to the literature in an effort to establish a common understanding of the differences in drilling methods, treatment fluids, and chemical additives and of how the newer technology has affected the water use volumes and areal distribution of hydraulic fracturing. Historically, Texas has had the highest number of records of hydraulic fracturing treatments and associated wells in the United States documented in the datasets described herein. Water-intensive horizontal/directional drilling has also increased from 6 percent of new hydraulically fractured wells drilled in the United States in 2000 to 42 percent of new wells drilled in 2010. Increases in horizontal drilling also coincided with the emergence of water-based “slick water” fracturing fluids. As such, the most current hydraulic fracturing materials and methods are notably different from those used in previous decades and have contributed to the development of previously inaccessible unconventional oil and gas production target areas, namely in shale and tight-sand reservoirs. Publicly available derivative datasets and locations developed from these analyses are described.

  4. Improvement of pressure text procedure for outside pour type hydraulic prop%外注式单体液压支柱试压工序的改进

    Institute of Scientific and Technical Information of China (English)

    欧艳梅

    2001-01-01

    This paper introduces the improving process of outside pour type hydraulic prop.It can reduce labour strength,raise pressure text safety and work efficiency.%介绍了外注式单体液压支柱试压头的改造过程,对其进行改进可以降低劳动强度,提高试压安全性能和劳动效率。

  5. Influence of temperature, pressure, and fluid salinity on the distribution of chlorine into serpentine minerals

    Science.gov (United States)

    Huang, Ruifang; Sun, Weidong; Zhan, Wenhuan; Ding, Xing; Zhu, Jihao; Liu, Jiqiang

    2017-09-01

    Serpentinization produces serpentine minerals that have abundant water and fluid-mobile elements (e.g., Ba, Cs, and Cl). The dehydration of serpentine minerals produces chlorine-rich fluids that may be linked with the genesis of arc magmas. However, the factors that control the distribution of chlorine into serpentine minerals remain poorly constrained. We performed serpentinization experiments at 80-500 °C and pressures from vapor saturated pressures to 20 kbar on peridotite, orthopyroxene, and olivine with pressure on the mobility of iron and silica. The experimental results of this study indicate that serpentine minerals are important carriers of chlorine in subduction zones. It also suggests that chlorine is significant for the redistribution of cations during serpentinization.

  6. Identification of an average temperature and a dynamical pressure in a multitemperature mixture of fluids.

    Science.gov (United States)

    Gouin, Henri; Ruggeri, Tommaso

    2008-07-01

    We present a classical approach to a mixture of compressible fluids when each constituent has its own temperature. The introduction of an average temperature together with the entropy principle dictates the classical Fick law for diffusion and also novel constitutive equations associated with the difference of temperatures between the components. The constitutive equations fit with results recently obtained through a Maxwellian iteration procedure in extended thermodynamics theory of multitemperature mixtures. The differences of temperatures between the constituents imply the existence of a dynamical pressure even if the fluids have a zero bulk viscosity. The nonequilibrium dynamical pressure can be measured and may be convenient in several physical situations, such as, for example, in cosmological circumstances where--as many authors assert--a dynamical pressure played a major role in the evolution of the early universe.

  7. Numerical Modeling of Pressurization of Cryogenic Propellant Tank for Integrated Vehicle Fluid System

    Science.gov (United States)

    Majumdar, Alok K.; LeClair, Andre C.; Hedayat, Ali

    2016-01-01

    This paper presents a numerical model of pressurization of a cryogenic propellant tank for the Integrated Vehicle Fluid (IVF) system using the Generalized Fluid System Simulation Program (GFSSP). The IVF propulsion system, being developed by United Launch Alliance, uses boiloff propellants to drive thrusters for the reaction control system as well as to run internal combustion engines to develop power and drive compressors to pressurize propellant tanks. NASA Marshall Space Flight Center (MSFC) has been running tests to verify the functioning of the IVF system using a flight tank. GFSSP, a finite volume based flow network analysis software developed at MSFC, has been used to develop an integrated model of the tank and the pressurization system. This paper presents an iterative algorithm for converging the interface boundary conditions between different component models of a large system model. The model results have been compared with test data.

  8. Reducing leaks in water distribution networks. Controlling pressure by means of automatic hydraulic valves; Reduccion de fugas en redes de distribucion de agua. Control de la presion mediante valvulas hidraulicas automaticas

    Energy Technology Data Exchange (ETDEWEB)

    Singla Font, S.

    2005-07-01

    Any water distribution network, bet it of drinking water or irrigation water, always loses an inevitable amount. One of the main ways to reduce leaks is to optimise the pressure in the network by means of hydraulic valves with different types of control devices. These can be either completely hydraulic or supplemented by electronic systems. (Author)

  9. The effect of pressure on open-framework silicates: elastic behaviour and crystal-fluid interaction

    Science.gov (United States)

    Gatta, G. D.; Lotti, P.; Tabacchi, G.

    2017-08-01

    The elastic behaviour and the structural evolution of microporous materials compressed hydrostatically in a pressure-transmitting fluid are drastically affected by the potential crystal-fluid interaction, with a penetration of new molecules through the zeolitic cavities in response to applied pressure. In this manuscript, the principal mechanisms that govern the P-behaviour of zeolites with and without crystal-fluid interaction are described, on the basis of previous experimental findings and computational modelling studies. When no crystal-fluid interaction occurs, the effects of pressure are mainly accommodated by tilting of (quasi-rigid) tetrahedra around O atoms that behave as hinges. Tilting of tetrahedra is the dominant mechanism at low-mid P-regime, whereas distortion and compression of tetrahedra represent the mechanisms which usually dominate the mid-high P regime. One of the most common deformation mechanisms in zeolitic framework is the increase of channels ellipticity. The deformation mechanisms are dictated by the topological configuration of the tetrahedral framework; however, the compressibility of the cavities is controlled by the nature and bonding configuration of the ionic and molecular content, resulting in different unit-cell volume compressibility in isotypic structures. The experimental results pertaining to compression in "penetrating" fluids, and thus with crystal-fluid interaction, showed that not all the zeolites experience a P-induced intrusion of new monoatomic species or molecules from the P-transmitting fluids. For example, zeolites with well-stuffed channels at room conditions (e.g. natural zeolites) tend to hinder the penetration of new species through the zeolitic cavities. Several variables govern the sorption phenomena at high pressure, among those: the "free diameters" of the framework cavities, the chemical nature and the configuration of the extra-framework population, the partial pressure of the penetrating molecule in the

  10. Monitoring the interaction of hydraulic fracturing fluid with Marcellus Shale using Sr isotopes: a comparison of laboratory experiments with field scale observations (Invited)

    Science.gov (United States)

    Wall, A. J.; Hakala, A.; Marcon, V.; Joseph, C.

    2013-12-01

    Strontium isotopes have the potential to be an effective tool for differentiating Marcellus Shale derived-fluids from other sources in surface and ground waters (Chapman et al. 2012, doi: 10.1021/es204005g). Water that is co-produced during gas extraction is likely influenced by fluid/rock interactions during hydraulic fracturing (HF) and monitoring changes in Sr isotope ratios can provide insight into reactions occurring within the shale formation. However, questions persist as to what controls the Sr isotopic composition of Marcellus Shale fluids, especially during HF. Here we compare laboratory experiments, simulating the dissolution of the Marcellus Shale during HF, with a time-series of water samples taken from a Marcellus Shale gas wells after HF has occurred. For the laboratory experiments, a core sample of Marcellus Shale from Greene County, PA was crushed and placed into a high P and T reaction vessel. Solutions were added in two different experiments: one with synthetic brine, and another using brine+HF fluid. The HF fluid was made up of components listed on fracfocus.org. Experiments were run for ~16 days at 27.5 MPa and 130oC. Aqueous samples were periodically removed for analysis and Sr isotope ratios were measured by MC-ICP-MS. Using just brine, the pH of the solution decreased from 7.6 to 5.3 after 24 hrs, then reached a steady state at ~6.1. Sr/Ca molar ratios in the fluid started at 2.3 after 24 hours and decreased to 1.8 over ~16 days. During this time only 6% of the total inorganic carbon (TIC) dissolved from the shale. The ɛSr values started at +43.2 and decreased to +42.4. In the experiment using brine+HF fluid, the pH started at 1.8 and rose slowly to a steady value of 5.6 by day 6. The Sr and Ca concentrations were higher than the brine experiment, but the Sr/Ca ratios remained lower at ~0.3 through the experiment. The increased Ca release, as well as the dissolution of over 60% of the TIC, suggests the dissolution of a carbonate mineral

  11. A Study Of Fluid Pressure Migration Within The North-Central Oklahoma Seismic Gap

    Science.gov (United States)

    Lambert, C.; Keranen, K. M.; Sickbert, T.

    2015-12-01

    The rise in seismicity in Oklahoma since 2008 provides an unusual opportunity to study fluid migration and the interaction of fluids with faults. One unique area in north-central Oklahoma is a current seismic gap between large clusters in northern and central Oklahoma, providing a window into the temporal evolution of local seismicity. The gap in seismicity occurs across the NNE-SSW trending Nemaha uplift, with long faults relatively well-oriented in the regional stress field. Wastewater disposal occurs both within and on either side of the gap, and seismicity approached both sides of the uplift in 2014. To record seismicity and seismic migration through time within the uplift and along the bounding faults on either side, we deployed a ten station array of broadband sensors in April 2015. Our goal is to detect possible seismic signals related to fluid pressure migration and to ultimately increase our understanding of the fault response to perturbations in fluid pressure. Here we present local earthquake locations from the first months of data and initial focal mechanisms. We detect higher numbers of earthquakes happening within the Nemaha uplift than recorded in existing catalogs. The seismicity is typically events. This pattern of seismicity may represent deformation on small faults as the pressure perturbation migrates into the Nemaha uplift from either side and away from wells within the uplift.

  12. Fluid inclusions evidence for differential exhumation of ultrahigh pressure metamorphic rocks in the Sulu terrane

    Institute of Scientific and Technical Information of China (English)

    FAN Hongrui; GUO Jinghui; HU Fangfang; CHU Xuelei; CHEN Fukun; JIN Chengwei

    2005-01-01

    Differential exhumation was petrologically recognized in ultrahigh pressure metamorphic rocks from the southern and northern parts of the Sulu terrane. While a normal exhumation occurred for eclogites and gneisses in south Sulu, granulite-facies overprinting of ultrahigh pressure metamorphic rocks took place with high retrograde temperatures in north Sulu. A study of fluid inclusions reveals trapping of five type fluid inclusions in high and ultrahigh pressure eclogite minerals and vein quartz in the Sulu terrane. These are A-type N2±CO2 inclusion trapped at high and ultra-high pressure eclogite-facies metamorphic condition, B-type pure-CO2 liquid phase inclusion with higher density trapped during granulite-facies overprinting metamorphism of eclogites, C-type CO2-H2O inclusion and D-type hypersaline inclusion trapped in high pressure eclogite-facies re-crystallization stage, and E-type low salinity H2O inclusion trapped in the latest stage of ultrahigh pressure exhumation (amphibolite-facies retrogression). Identification of crowded-distributing pure-CO2 liquid inclusions with higher density trapped in garnet of eclogites provides an evidence for granulite-facies overprinting metamorphism in the north Sulu terrane.

  13. Effects of hypoproteinemia on renal hemodynamics, arterial pressure, and fluid volume

    Energy Technology Data Exchange (ETDEWEB)

    Manning, R.D. Jr.

    1987-01-01

    The effects of long-term hypoproteinemia on renal hemodynamics, arterial pressure, and fluid volume were studied in eight conscious dogs over a 34-day period. Plasma protein concentration (PPC) was decreased by daily plasmapheresis, and the effects of decreasing and increasing sodium intake were measured. By the 12th day of plasmapheresis PPC had decreased to 2.5 g/dl from a control value of 7.2 g/dl, mean arterial pressure had decreased to 78% of control, glomerular filtration rate (GFR) was 75.2% of control, and urinary sodium excretion was decreased. By day 18 of plasmapheresis, estimated renal plasma flow (ERPF) was decreased to 60% of control due to the decreased arterial pressure and an increase in renal vascular resistance. GFR and ERPF were determined from the total clearance of (/sup 125/I)iothalamate and (/sup 131/I)iodohippurate. Also, plasma renin activity and plasma aldosterone concentration were both increased, and the relationship between mean arterial pressure and urinary sodium excretion was distinctly shifted to the left along the arterial pressure axis. In contradistinction to acute experiments, chronic hypoproteinemia results in decreases in GFR, ERPF, and urinary sodium excretion and has marked effects on both fluid volume and arterial pressure regulation.

  14. Experimental studies on dynamic system characteristics of the high temperature/high pressure thermal-hydraulic test facility(VISTA) for the power variation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, K. Y.; Park, H. S.; Joe, S.; Park, C. K.; Lee, S. J.; Song, C. W.; Jeong, M. K. [KAERI, Taejon (Korea, Republic of)

    2003-10-01

    Dynamic system characteristics tests were carried out for the power variation by using the high temperature/high pressure thermal-hydraulic test facility, VISTA(Experimental Verification by Integral Simulation of Transient and Accidents), which had been constructed to simulate the SMART-P by KAERI. Experimental tests have been performed to investigate the thermal-hydraulic dynamic characteristics of the primary and the secondary systems in the range of 5% to 85% power. Automatic PID control logics were developed and installed to the VISTA facility to control the major thermal hydraulic parameters. Power was changed with either a step or a ramp changing method from the reference power of 10%, 25%, 50% and 75% to 5% or 10% higher power. It was found that there is no noticeable difference in the responses between a step and a ramp changing method. When unique constants of P, I, and D were used in the range of 5% to 85% power, it was found to be liable to lose the system control. Further studies are required to quantify the controllability and the time constants of the major thermal hydraulic parameters.

  15. Phase Envelope Calculations for Reservoir Fluids in the Presence of Capillary Pressure

    DEFF Research Database (Denmark)

    Lemus, Diego; Yan, Wei; Michelsen, Michael L.

    2015-01-01

    Reservoir fluids are multicomponent mixtures in confined spaces, where the role of capillary force becomes important when the average pore size is on the order of tens of nanometers, such as in tight rocks and shale. We present an algorithm for calculating the phase envelope of multicomponent...... the bubble and dew point curves but also other quality lines with vapor fractions between 0 and 1. The algorithm has been used to calculate the phase envelopes of binary, multicomponent and reservoir fluid systems for pore radius from 10 to 50 nm. The presence of capillary pressure changes the saturation...

  16. Effect of lower-body positive pressure on postural fluid shifts in men

    Science.gov (United States)

    Hinghofer-Szalkay, H.; Kravik, S. E.; Greenleaf, J. E.

    1988-01-01

    The effect of the lower-body positive pressure (LBPP) on the orthostatic fluid and protein shifts were investigated in five men during combined tilt-table/antigravity suit inflation and deflation experiments. Changes in the mass densities of venous blood and plasma were measured and the values were used to calculate the densities of erythrocytes, whole-body blood, and shifted fluid. It was found that the application of 60 mm Hg LBPP during 60-deg head-up tilt prevented about half of the postural hemoconcentration occurring during passive head-up tilt.

  17. Pressure wave propagation in fluid-filled co-axial elastic tubes. Part 1: Basic theory.

    Science.gov (United States)

    Berkouk, K; Carpenter, P W; Lucey, A D

    2003-12-01

    Our work is motivated by ideas about the pathogenesis of syringomyelia. This is a serious disease characterized by the appearance of longitudinal cavities within the spinal cord. Its causes are unknown, but pressure propagation is probably implicated. We have developed an inviscid theory for the propagation of pressure waves in co-axial, fluid-filled, elastic tubes. This is intended as a simple model of the intraspinal cerebrospinal-fluid system. Our approach is based on the classic theory for the propagation of longitudinal waves in single, fluid-filled, elastic tubes. We show that for small-amplitude waves the governing equations reduce to the classic wave equation. The wave speed is found to be a strong function of the ratio of the tubes' cross-sectional areas. It is found that the leading edge of a transmural pressure pulse tends to generate compressive waves with converging wave fronts. Consequently, the leading edge of the pressure pulse steepens to form a shock-like elastic jump. A weakly nonlinear theory is developed for such an elastic jump.

  18. Employing numerical fluid mechanics in the development of hydraulic turbo-engines; Einsatz der numerischen Stroemungsmechanik in der Entwicklung hydraulischer Stroemungsmaschinen

    Energy Technology Data Exchange (ETDEWEB)

    Ruprecht, A.; Bauer, C.; Chihab, W.; Gentner, C.; Ginter, F.; Maihoefer, M.; Welzel, B.

    1994-12-31

    Numerical fluid mechanics as a method for the dimensioning and optimization of components of hydraulic turbo-engines is coming into prominence. In hydraulic systems, flows are almost exclusively turbulent with very high Reynolds` numbers. This is why Reynolds`-averaged Navier-Stokes equations are solved. Direct numerical solutions or coarse structure simulations are not possible as yet. In order to describe the turbulence, a turbulence model needs to be used. An optimum compromise between accuracy, general validity and computation effort for complex three-dimensional flows exists in the form of the k-{epsilon} model. To be sure, this model has some weak points (for instance, in the case of a strong streamline curvature), but on the whole it does provide satisfactory results. (orig./AKF) [Deutsch] Der Einsatz der numerischen Stroemungsmechanik zur Auslegung und Optimierung von Bauteilen hydraulischer Stroemungsmaschinen gewinnt stark an Bedeutung. In hydraulischen Anlagen liegen fast ausschliesslich turbulente Stroemungen bei sehr hohen Reynoldszahlen vor. Deshalb werden die Reynolds-gemittelte Navier-Stokesbleichungen geloest. Direkte numerische Loesungen oder Grobstruktursimulationen sind heute noch nicht moeglich. Zur Beschreibung der Turbulenz muss ein Turbulenzmodell verwendet werden. Einen optimalen Kompromiss zwischen Genauigkeit, Allgemeingueltigkeit und Rechenaufwand bei komplexen dreidimensionalen Stroemungen stellt das k-{epsilon} Modell dar. Zwar besitzt dieses Modell einige Schwachpunkte (z.B. bei starker Stromlinienkruemmung) es liefert aber i.a. doch befriedigende Ergebnisse. (orig./AKF)

  19. Inertial migration of elastic particles in a pressure-driven power-law fluid

    Science.gov (United States)

    Bowie, Samuel; Alexeev, Alexander

    2016-11-01

    Using three-dimensional computer simulations, we study the cross-stream migration of deformable particles in a channel filled with a non-Newtonian fluid driven by a pressure gradient. Our numerical approach integrates lattice Boltzmann method and lattice spring method in order to model fluid structural interactions of the elastic particle and the surrounding power fluid in the channel. The particles are modeled as elastic shells filled with a viscous fluid that are initially spherical. We focus on the regimes where the inertial effects cannot be neglected and cause cross-stream drift of particles. We probe the flow with different power law indexes including both the shear thickening and thinning fluids. We also examine migration of particles of with different elasticity and relative size. To isolate the non-Newtonian effects on particle migration, we compare the results with the inertial migration results found in the case where the channel is filled with a simple Newtonian fluid. The results can be useful for applications requiring high throughput separation, sorting, and focusing of both synthetic particles and biological cells in microfluidic devices. Financial support provided by National Science Foundation (NSF) Grant No. CMMI1538161.

  20. Natural occurrence and significance of fluids indicating high pressure and temperature

    Science.gov (United States)

    Roedder, E.

    1981-01-01

    Most natural minerals have formed from a fluid phase such as a silicate melt or a saline aqueous solution. Fluid inclusions are tiny volumes of such fluids that were trapped within the growing crystals. These inclusions can provide valuable but sometimes ambiguous data on the temperature, pressure, and composition of these fluids, many of which are not available from any other source. They also provide "visual autoclaves" in which it is possible to watch, through the microscope, the actual phase changes take place as the inclusions are heated. This paper reviews the methods of study and the results obtained, mainly on inclusions formed from highly concentrated solutions, at temperatures ???500??C. Many such fluids have formed as a result of immiscibility with silicate melt in igneous or high-temperature metamorphic rocks. These include fluids consisting of CO2, H2O, or hydrosaline melts that were copper deposits in the world. Similarly, from the inclusion evidence it is clear that early (common) pegmatites formed from essentially silicate melts and that the late, rare-element-bearing and chamber-type pegmatites formed from a hydrosaline melt or a more dilute water solution. The evidence on whether this change in composition from early to late solutions was generally continuous or involved immiscibility is not as clear. ?? 1981.

  1. Discussion on Methods of Proportional Pressure Control in Hydraulic System of Hydraulic Press%液压机液压系统比例压力控制方法探讨

    Institute of Scientific and Technical Information of China (English)

    李贵闪; 翟华

    2011-01-01

    Three methods of proportional pressure control on hydraulic presses were introduced and compared, which were open-loop control, closed-loop control based on PID and PID control with addition of initial signals. Results of comparison showe that the closed-loop control algorithm which is added with initial signals has many advantages such as simple control structure, easy debugging operations, stable system and high precision, and etc. The requirements of this hydraulic press on pressure control can be fully satisfied.%介绍了液压机比例压力控制的3种方法,即开环控制、基于PID的闭环控制、加入初始信号的PID控制.并对3种控制方法进行了比较.结果表明:采取的加入初始信号的闭环控制算法具有控制结构简单、调试方便、系统稳定、精度高等优点,完全满足该液压机对压力控制的要求.

  2. Adsorption of hydraulic fracturing fluid components 2-butoxyethanol and furfural onto granular activated carbon and shale rock.

    Science.gov (United States)

    Manz, Katherine E; Haerr, Gregory; Lucchesi, Jessica; Carter, Kimberly E

    2016-12-01

    The objective of this study was to understand the adsorption ability of a surfactant and a non-surfactant chemical additive used in hydraulic fracturing onto shale and GAC. Experiments were performed at varying temperatures and sodium chloride concentrations to establish these impacts on the adsorption of the furfural (a non-surfactant) and 2-Butoxyethanol (2-BE) (a surfactant). Experiments were carried out in continuously mixed batch experiments with Langmuir and Freundlich isotherm modeling. The results of the experiments showed that adsorption of these compounds onto shale does not occur, which may allow these compounds to return to the surface in flowback and produced waters. The adsorption potential for these chemicals onto GAC follows the assumptions of the Langmuir model more strongly than those of the Freundlich model. The results show uptake of furfural and 2-BE occurs within 23 h in the presence of DI water, 0.1 mol L(-1) sodium chloride, and in lab synthesized hydraulic fracturing brine. Based on the data, 83% of the furfural and 62% of the 2-BE was adsorbed using GAC.

  3. Improving energy efficiency in robot limbs through hydraulic dangle

    Science.gov (United States)

    Whitman, Julian S.; Meller, Mike; Garcia, Ephrahim

    2015-03-01

    Animals often allow their limbs to swing passively under their own inertia. For example, about 40% of a human walking gait consists of the primarily passive swing phase. Current hydraulic robots employ traditional actuation methods in which fluid power is expended for all limb movements, even when passive dynamics could be utilized. "Dangle" is the ability to allow a hydraulic actuator to freely sway in response to external loads, in which both sides of the actuator are disconnected from pressure and connected to the tank. Dangle offers the opportunity for efficiency gains by enabling the use of momentum, gravity, and external loads to move a limb without expending fluid power. To demonstrate these efficiency gains, this paper presents an experiment that compares the fluid power consumed to actuate a two degree of freedom hydraulic leg following a human walking gait cycle trajectory in both a traditional manner and utilizing dangle. It was shown that the use of dangle can decrease fluid power consumption by 20% by utilizing pendular dynamics during the swing phase. At speeds higher than the free dangling rate, more power must be used to maintain the desired trajectory due to damping inherent in the configuration. The use of dangle as a power saving method when driving hydraulic limbs could increase operation time for untethered hydraulic walking robots.

  4. Irrigation dynamics associated with positive pressure, apical negative pressure and passive ultrasonic irrigations: a computational fluid dynamics analysis.

    Science.gov (United States)

    Chen, José Enrique; Nurbakhsh, Babak; Layton, Gillian; Bussmann, Markus; Kishen, Anil

    2014-08-01

    Complexities in root canal anatomy and surface adherent biofilm structures remain as challenges in endodontic disinfection. The ability of an irrigant to penetrate into the apical region of a canal, along with its interaction with the root canal walls, will aid in endodontic disinfection. The aim of this study was to qualitatively examine the irrigation dynamics of syringe irrigation with different needle tip designs (open-ended and closed-ended), apical negative pressure irrigation with the EndoVac® system, and passive ultrasonic-assisted irrigation, using a computational fluid dynamics model. Syringe-based irrigation with a side-vented needle showed a higher wall shear stress than the open-ended but was localised to a small region of the canal wall. The apical negative pressure mode of irrigation generated the lowest wall shear stress, while the passive-ultrasonic irrigation group showed the highest wall shear stress along with the greatest magnitude of velocity.

  5. Analysis report of the thermal-hydraulic characteristics of the high temperature/high pressure thermal-hydraulic test facility (VISTA) in steady state conditions

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun Sik; Choi, Ki Yong; Cho, Seok; Lee, Sung Jae; Song, Chul Hwa; Park, Chun Kyong; Chung, Moon Ki

    2004-01-01

    The VISTA (Experimental Verification by Integral Simulation of Transients and Accidents) is an experimental facility to verify the performance and safety issues of the SMART-P (Pilot plant of the system-integrated modular advanced reactor). The basic design of the SMART-P has been completed by KAERI. The present report describes the experimental results on the water inventory distribution, the pressure distribution, and the differential pressure characteristics of the VISTA facility and on the heat transfer characteristics of the core simulating heater and the steam generator of the VISTA facility. There were little differences of their water inventories between the designed and the measured data. The pressure of the VISTA primary system kept near the steady-state operating pressure of 147 bar, and the differential pressures through the primary and secondary systems increased with the increase of their flow rates. Also the surface temperatures of core simulating heaters were measured, and the overall heat transfer coefficient of the VISTA steam generator was calculated to show a little higher values than that of the SMART-P.

  6. Nonlinear, Adaptive and Fault-tolerant Control for Electro-hydraulic Servo Systems

    DEFF Research Database (Denmark)

    Choux, Martin

    Fluid power systems have been in use since 1795 with the rst hydraulic press patented by Joseph Bramah and today form the basis of many industries. Electro hydraulic servo systems are uid power systems controlled in closed-loop. They transform reference input signals into a set of movements...... in hydraulic actuators (cylinders or motors) by the means of hydraulic uid under pressure. With the development of computing power and control techniques during the last few decades, they are used increasingly in many industrial elds which require high actuation forces within limited space. However, despite...... 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...

  7. Numerical Modeling of an Integrated Vehicle Fluids System Loop for Pressurizing a Cryogenic Tank

    Science.gov (United States)

    LeClair, A. C.; Hedayat, A.; Majumdar, A. K.

    2017-01-01

    This paper presents a numerical model of the pressurization loop of the Integrated Vehicle Fluids (IVF) system using the Generalized Fluid System Simulation Program (GFSSP). The IVF propulsion system, being developed by United Launch Alliance to reduce system weight and enhance reliability, uses boiloff propellants to drive thrusters for the reaction control system as well as to run internal combustion engines to develop power and drive compressors to pressurize propellant tanks. NASA Marshall Space Flight Center (MSFC) conducted tests to verify the functioning of the IVF system using a flight-like tank. GFSSP, a finite volume based flow network analysis software developed at MSFC, has been used to support the test program. This paper presents the simulation of three different test series, comparison of numerical prediction and test data and a novel method of presenting data in a dimensionless form. The paper also presents a methodology of implementing a compressor map in a system level code.

  8. Numerical vs experimental pressure drops for Boger fluids in sharp-corner contraction flow

    Science.gov (United States)

    López-Aguilar, J. E.; Tamaddon-Jahromi, H. R.; Webster, M. F.; Walters, K.

    2016-10-01

    This paper addresses the problem of matching experimental findings with numerical prediction for the extreme experimental levels of pressure-drops observed in the 4:1 sharp-corner contraction flows, as reported by Nigen and Walters ["Viscoelastic contraction flows: Comparison of axisymmetric and planar configurations," J. Non- Newtonian Fluid Mech. 102, 343-359 (2002)]. In this connection, we report on significant success in achieving quantitative agreement between predictions and experiments. This has been made possible by using a new swanINNFM model, employing an additional dissipative function. Notably, one can observe that extremely large pressure-drops may be attained with a suitable selection of the extensional viscous time scale. In addition, and on vortex structure, the early and immediate vortex enhancement for Boger fluids in axisymmetric contractions has also been reproduced, which is shown to be absent in planar counterparts.

  9. Pressure Distribution in a Porous Squeeze Film Bearing Lubricated with a Herschel-Bulkley Fluid

    Directory of Open Access Journals (Sweden)

    Walicka A.

    2016-12-01

    Full Text Available The influence of a wall porosity on the pressure distribution in a curvilinear squeeze film bearing lubricated with a lubricant being a viscoplastic fluid of a Herschel-Bulkley type is considered. After general considerations on the flow of the viscoplastic fluid (lubricant in a bearing clearance and in a porous layer the modified Reynolds equation for the curvilinear squeeze film bearing with a Herschel-Bulkley lubricant is given. The solution of this equation is obtained by a method of successive approximation. As a result one obtains a formula expressing the pressure distribution. The example of squeeze films in a step bearing (modeled by two parallel disks is discussed in detail.

  10. Fluid description of Weibel-type instabilities via full pressure tensor dynamics

    Science.gov (United States)

    Sarrat, M.; Del Sarto, D.; Ghizzo, A.

    2016-08-01

    We discuss a fluid model for the description of Weibel-type instabilties based on the inclusion of the full pressure tensor dynamics. The linear analysis first performed by Basu B., Phys. Plasmas, 9, (2002) 5131, for the strong anisotropy limit of Weibel's instability is extended to include the coupling between pure Weibel's and current filamentation instability, and the potential of this fluid approach is further developed. It is shown to allow an easier interpretation of some physical features of these coupled modes, notably the role played by thermal effects. It can be used to identify the role of different closure conditions in pressure-driven instabilities which can be numerically investigated at a remarkably lower computational cost than with kinetic simulations.

  11. Modeling of fluid dynamics interacting with ductile fraction propagation in high pressure pipeline

    Institute of Scientific and Technical Information of China (English)

    Mihaela Popescu

    2009-01-01

    This paper presents a computational model for the fluid dynamics in a fractured ductile pipe under high pressure. The pressure profile in front of the crack tip, which is the driving source of crack propagation, is computed using a nonlinear wave equation. The solution is coupled with a one dimensional choked flow analysis behind the crack. The simulation utilizes a high order optimized prefactored com-pact-finite volume method in space, and low dispersion and dissipation Runge-Kutta in time. As the pipe fractures the rapid depressurization take place inside the pipe and the prop-agation of the crack-induced waves strongly influences the outflow dynamics. Consistent with the experimental observa-tion, the model predicts the expansion wave inside the pipe, and the reflection and outflow of the wave. The model also helps characterize the propagation of the crack dynamics and fluid flows around the tip of the crack.

  12. Progesterone reduces sympathetic tone without changing blood pressure or fluid balance in men.

    Science.gov (United States)

    Tollan, A; Oian, P; Kjeldsen, S E; Eide, I; Maltau, J M

    1993-01-01

    There is scant information on the effects of progesterone on circulation. Changes in catecholamine levels, blood pressure and transcapillary fluid balance were measured in 12 men before and during administration of natural progesterone (Utrogestan). Before administration, systolic blood pressure was significantly correlated with venous adrenaline (r = 0.67, p = 0.01). There was a significant decrease (p = 0.004) in venous noradrenaline during progesterone administration, and systolic blood pressure was significantly correlated with the arteriovenous difference for noradrenaline (r = 0.66, p = 0.02). Serum progesterone, which attained levels similar to those found in women during the luteal phase, did not significantly alter blood pressure, body weight or intra- to extravascular fluid shift. It is concluded that progesterone may have a direct action by increasing the uptake of noradrenaline from the synaptic cleft or by decreasing the nerve firing rate. Interestingly, the pretreatment finding of a significant correlation between blood pressure and adrenaline was less evident during progesterone administration.

  13. Fast fluid-flow events within a subduction-related vein system in oceanic eclogite: implications for pore fluid pressure at the plate interface

    Science.gov (United States)

    Taetz, Stephan; John, Timm; Bröcker, Michael; Spandler, Carl; Stracke, Andreas

    2017-04-01

    A better understanding of the subduction zone fluid cycle and its mechanical feedback requires in-depth knowledge of how fluids flow within and out of the descending slabs. In order to develop reliable quantitative models of fluid flow, the general relationship between dehydration reactions, fluid pathway formation, and the dimensions and timescales of distinct fluid flow events have to be explored. The high-pressure/low-temperature metamorphic rocks of the Pouébo Eclogite Mélange in New Caledonia provide an excellent opportunity to study the fluid flux in a subduction zone setting. Fluid dynamics are recorded by high-pressure veins that cross-cut eclogite facies mélange blocks from this occurrence. Two types of garnet-quartz-phengite veins can be distinguished. These veins record both synmetamorphic internal fluid release by mineral breakdown reactions (type I veins) as well as infiltration of an external fluid (type II veins) and the associated formation of a reaction halo. The overall dehydration, fluid accumulation and fluid migration documented by the type I veins occurred on a timescale of 10^5-106 years that is mainly given by the geometry and convergence rate of the subduction system. In order to quantify the timeframe of fluid-rock interaction between the external fluid and the wall-rock, we have applied Li-isotope chronology. A continuous profile was sampled perpendicular to a type II vein including material from the vein, the reaction selvage and the immediate host rock. Additional drill cores were taken from parts of the outcrop that most likely remained completely unaffected by fluid infiltration-induced alteration. Different Li concentrations in the internal and external fluid reservoirs produced a distinct diffusion profile of decreasing Li concentration and increasing δ7Li as the reaction front propagated into the host-rock. Li-chronometric constraints indicate that fluid-rock interaction related to the formation of the type II veins and had

  14. Dentinal fluid dynamics in human teeth, in vivo.

    Science.gov (United States)

    Ciucchi, B; Bouillaguet, S; Holz, J; Pashley, D

    1995-04-01

    Cavities were prepared in human premolars scheduled for extraction for orthodontic reasons. The smear layer was removed from the dentin surface by acid etching, and the cavity was sealed using a hollow chamber. The chamber was filled with sterile saline solution and connected via tubing to a hydraulic circuit featuring an adjustable pressure reservoir and a device that measures fluid movement across dentin. In the absence of any exogenous pressure, all cavities exhibited an outward fluid flow rate of 0.36 microliters min-1 cm-2. As exogenous pressure was applied to the cavity, the outward flow slowed. The exogenous pressure that stopped outward fluid flow was taken to be equal to normal pulpal tissue pressure. The mean value was 14.1 cm H2O in five teeth. This simple method permits measurement of dentinal fluid flux, the hydraulic conductance of dentin, and estimates pulpal tissue pressure.

  15. On the Versatility of Rheoreversible, Stimuli-responsive Hydraulic-Fracturing Fluids for Enhanced Geothermal Systems: Effect of Reservoir pH

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Carlos A.; Shao, Hongbo; Bonneville, Alain; Varga, Tamas; Zhong, Lirong

    2016-04-25

    Abstract The primary challenge for the feasibility of enhanced geothermal systems (EGS) is to cost-effectively create high-permeability reservoirs inside deep crystalline bedrock. Although fracturing fluids are commonly used for oil/gas, standard fracturing methods are not developed or proven for EGS temperatures and pressures. Furthermore, the environmental impacts of currently used fracturing methods are only recently being determined. These authors recently reported an environmentally benign, CO2-activated, rheoreversible fracturing fluid that enhances permeability through fracturing due to in situ volume expansion and gel formation. The potential of this novel fracturing fluid is evaluated in this work towards its application at geothermal sites under different pH conditions. Laboratory-scale fracturing experiments using Coso Geothermal rock cores under different pH environments were performed followed by X-ray microtomography characterization. The results demonstrate that CO2-reactive aqueous solutions of environmentally amenable polyallylamine (PAA) consistently and reproducibly creates/propagates fracture networks through highly impermeable crystalline rock from Coso EGS sites at considerably lower effective stress as compared to conventional fracturing fluids. In addition, permeability was significantly enhanced in a wide range of formation-water pH values. This effective, and environmentally-friendly fracturing fluid technology represents a potential alternative to conventional fracturing fluids.

  16. The Analysis of Fluid Pressure Impact on String Force and Deformation in Oil and Gas Wells

    Directory of Open Access Journals (Sweden)

    Gao Baokui

    2015-01-01

    Full Text Available Fluid pressure is a crucial factor to tubular string strength and deformation in oil and gas wells, and it is the most difficult factor to deal with. When the string constrained by downhole tools, such as packers, action pattern of fluid on string is changed. Calculation methods of string stress and deformation given by engineering handbooks doesn’t distinguish these issues in detail. So mistakes are often made when these methods are used. Tangled concepts lead to large calculation error. In this paper, the influence of fluid pressure on string axial force and deformation, buoyancy treatment in packed condition, are discussed roundly both in vertical wells and directional wells. Practical calculating method of string axial force through the hook load is presented, and element buoyancy in different borehole trajectory is given. It is found that the traditional simplified buoyancy coefficient method, which is used to calculate string axial force and axial extension, can only be used in vertical wells with tubular string suspended freely, because in this condition buoyancy acts on the bottom of string. If the string is constrained by downhole tools, such as packer or anchor, buoyancy could not be treated as usual. In directional well the buoyancy not only changes string axial force but induces shear stress in string cross section. When calculating the influence of fluid on string, operation sequence and constraints from borehole and downhole tools should be considered comprehensively.

  17. Acoustoelastic effects on mode waves in a fluid-filled pressurized borehole in triaxially stressed formations

    Institute of Scientific and Technical Information of China (English)

    Ping'en Li; Youquan Yin; Xianyue Su

    2006-01-01

    Based on the nonlinear theory of acoustoelasticity,considering the triaxial terrestrial stress,the fluid static pressure in the borehole and the fluid nonlinear effect jointly,the dispersion curves of the monopole Stoneley wave and dipole flexural wave propagating along the borehole axis in a homogeneous isotropic formation are investigated by using the perturbation method.The relation of the sensitivity coefficient and the velocity-stress coefficient to frequency are also analyzed.The results show that variations of the phase velocity dispersion curve are mainly affected by three sensitivity coefficients related to third-order elastic constant.The borehole stress concentration causes a split of the flexural waves and an intersection of the dispersion curves of the flexural waves polarized in directions parallel and normal to the uniaxial horizontal stress direction.The stress-induced formation anisotropy is only dependent on the horizontal deviatoric terrestrial stress and independent of the horizontal mean terrestrial stress,the superimposed stress and the fluid static pressure.The horizontal terrestrial stress ratio ranging from 0 to 1 reduces the stress-induced formation anisotropy.This makes the intersection of flexural wave dispersion curves not distinguishable.The effect of the fluid nonlinearity on the dispersion curve of the mode wave is small and can be ignored.

  18. Effects of Supercritical Fluids, Pressure, Temperature, and Molecular Structure on the Rheological Properties of Molten Polymers

    Science.gov (United States)

    Park, Hee Eon; Dealy, John M.

    2008-07-01

    Since high pressures are involved in most plastics forming processes, reliable high-pressure rheological data are required for the simulation of the processes. The effect of pressure is in some ways the reverse of that of temperature; for example increasing temperature decreases the viscosity, while pressure increases it. Supercritical fluids (SCFs) such as carbon dioxide and nitrogen can act as physical blowing agents in the manufacture of foams and as plasticizers to reduce melt viscosity during processing. The effects of dissolved SCF, pressure, and temperature on the rheological properties of a melt must be known to achieve optimum processing conditions. We used a rotational rheometer and a high-pressure sliding plate rheometer, in which the shear strain, temperature, pressure, and SCF concentration are all uniform. A shear stress transducer senses the stress in the center of the sample to avoid edge effects. It was possible to use shift factors for temperature, pressure and SCF (CO2 or N2) concentration to obtain a master curve. The effect of temperature could be described by the Arrhenius or WLF models, and the effect of pressure was described by the Barus equation. The effect of SCF concentration could be described by the Fujita-Kishimoto equation. The relative effects of pressure and temperature on the viscosity were quantified. To study the effects of short and long chain branching and a phenyl side group, three polymers were used: polyethylene, polypropylene, and polystyrene. We quantified the effects of short- and long-chain branching, pressure, temperature and dissolved SCF on the rheological properties of these three polymers by use of shift factors.

  19. Subharmonic aided pressure estimation for monitoring interstitial fluid pressure in tumours--in vitro and in vivo proof of concept.

    Science.gov (United States)

    Halldorsdottir, V G; Dave, J K; Eisenbrey, J R; Machado, P; Zhao, H; Liu, J B; Merton, D A; Forsberg, F

    2014-09-01

    The feasibility of using subharmonic aided pressure estimation (SHAPE) to noninvasively estimate interstitial fluid pressure (IFP) was studied. In vitro, radiofrequency signals, from 0.2 ml/l of Definity (Lantheus Medical Imaging, N Billerica, MA) were acquired within a water-tank with a Sonix RP ultrasound scanner (Analogic Ultrasound, Richmond, BC, Canada; fT/R=6.7/3.35 MHz and fT/R=10/5 MHz) and the subharmonic amplitudes of the signals were compared over 0-50 mmHg. In vivo, five swine with naturally occurring melanomas were studied. Subharmonic signals were acquired from tumours and surrounding tissue during infusion of Definity and compared to needle-based pressure measurements. Both in vitro and in vivo, an inverse linear relationship between hydrostatic pressure and subharmonic amplitude was observed with r(2)=0.63-0.95; p<0.05, maximum amplitude drop 11.36 dB at 10 MHz and -8 dB, and r(2) as high as 0.97; p<0.02 (10 MHz and -4/-8 dB most promising), respectively, indicating that SHAPE may be useful in monitoring IFP.

  20. A paradigm shift in predicting stormflow responses in an active tectonic region through a similarity analysis of pressure propagation in a hydraulic continuum

    Directory of Open Access Journals (Sweden)

    Makoto Tani

    2013-06-01

    Full Text Available Soil layers on hillslopes acts as systems in quasi-steady states generating rainfall-stormflow responses that are controlled by pressure propagation in a hydraulic continuum established when the rainfall volume is sufficiently large. A similarity analysis for quantifying the sensitivity of the stormflow response and recession limb to topographic and soil properties in a sloping permeable domain showed that the deviation of stormflow responses in the hydraulic continuum decreases due to the macropore effect. The rapid responses seem to be naturally derived from the evolution of the soil layer with the assistance of the vegetation-root system and effective drainage systems in zero-order catchments in active tectonic regions with heavy storms. To predict stormflow responses using distributed runoff models, a paradigm shift to consider this evolution process is needed because the simple stormflow responses and complex and heterogeneous catchment properties are poorly related, but may be mainly determined by soil evolution processes.

  1. Experimental studies on heat transfer characteristics and natural circulation performance of PRHRS of the high temperature and high pressure thermal-hydraulic test facility

    Energy Technology Data Exchange (ETDEWEB)

    Park, H. S.; Choi, K. Y.; Joe, S.; Park, C. K.; Lee, S. J.; Song, C. W.; Jeong, M. K. [KAERI, Taejon (Korea, Republic of)

    2003-10-01

    Several experiments are performed to investigate the heat transfer characteristics and natural circulation performance of passive residual removal system (PRHRS) of the high temperature and high pressure thermal-hydraulic test facility. Especially the natural circulation performance of PRHRS, the heat transfer characteristics of PRHRS heat exchangers and emergency cooldown tank (ECT), and the thermal-hydraulic behavior of the primary loop are investigated in detail. The coolant flows steadily in the natural circulation loop which is composed of the steam generator (SG) primary side, the secondary system, and the PRHRS. The heat transfers through the PRHRS heat exchanger and ECT are sufficient enough to enable the natural circulation of the coolant. Also the experimental results show that the core decay heat are sufficiently removed with the operation of the PRHRS.

  2. Australasian Conference on Hydraulics and Fluid Mechanics, 7th, Brisbane, Australia, August 18-22, 1980, Preprints of Papers

    Science.gov (United States)

    A review is provided of research and developments in hydraulics in Australasia during the past decade, and aspects of prospecting for wind energy are explored. Power generation from the East Australian current by use of arrays of submerged Darrieus vertical axis turbines is considered along with normal stress measurements for viscoelastic liquids using real time holographic interferometry of the Weissenberg effect, admissibility requirements and the least squares finite element solution for potential flow, two-dimensional solid blockage in a slotted wall wind tunnel, and the dynamic behavior of propeller anemometers. Attention is given to the potential flow signature of a turbulent spot, topographic forcing in nonlinear and linear barotropic models, flow control by secondary injection, friction factors of aqueous electrolyte solutions in pipe flow, the vortex shedding process behind a circular cylinder, and the use of the method of lines for choking flow in a nozzle.

  3. Apparatus and method for fatigue testing of a material specimen in a high-pressure fluid environment

    Science.gov (United States)

    Wang, Jy-An; Feng, Zhili; Anovitz, Lawrence M; Liu, Kenneth C

    2013-06-04

    The invention provides fatigue testing of a material specimen while the specimen is disposed in a high pressure fluid environment. A specimen is placed between receivers in an end cap of a vessel and a piston that is moveable within the vessel. Pressurized fluid is provided to compression and tension chambers defined between the piston and the vessel. When the pressure in the compression chamber is greater than the pressure in the tension chamber, the specimen is subjected to a compression force. When the pressure in the tension chamber is greater than the pressure in the compression chamber, the specimen is subjected to a tension force. While the specimen is subjected to either force, it is also surrounded by the pressurized fluid in the tension chamber. In some examples, the specimen is surrounded by hydrogen.

  4. Effect of pressurization on helical guided wave energy velocity in fluid-filled pipes.

    Science.gov (United States)

    Dubuc, Brennan; Ebrahimkhanlou, Arvin; Salamone, Salvatore

    2017-03-01

    The effect of pressurization stresses on helical guided waves in a thin-walled fluid-filled pipe is studied by modeling leaky Lamb waves in a stressed plate bordered by fluid. Fluid pressurization produces hoop and longitudinal stresses in a thin-walled pipe, which corresponds to biaxial in-plane stress in a plate waveguide model. The effect of stress on guided wave propagation is accounted for through nonlinear elasticity and finite deformation theory. Emphasis is placed on the stress dependence of the energy velocity of the guided wave modes. For this purpose, an expression for the energy velocity of leaky Lamb waves in a stressed plate is derived. Theoretical results are presented for the mode, frequency, and directional dependent variations in energy velocity with respect to stress. An experimental setup is designed for measuring variations in helical wave energy velocity in a thin-walled water-filled steel pipe at different levels of pressure. Good agreement is achieved between the experimental variations in energy velocity for the helical guided waves and the theoretical leaky Lamb wave solutions.

  5. Seismic monitoring of hydraulic fracturing: techniques for determining fluid flow paths and state of stress away from a wellbore

    Energy Technology Data Exchange (ETDEWEB)

    Fehler, M.; House, L.; Kaieda, H.

    1986-01-01

    Hydraulic fracturing has gained in popularity in recent years as a way to determine the orientations and magnitudes of tectonic stresses. By augmenting conventional hydraulic fracturing measurements with detection and mapping of the microearthquakes induced by fracturing, we can supplement and idependently confirm information obtained from conventional analysis. Important information obtained from seismic monitoring includes: the state of stress of the rock, orientation and spacing of the major joint sets, and measurements of rock elastic parameters at locations distant from the wellbore. While conventional well logging operations can provide information about several of these parameters, the zone of interrogation is usually limited to the immediate proximity of the borehole. The seismic waveforms of the microearthquakes contain a wealth of information about the rock in regions that are otherwise inaccessible for study. By reliably locating the hypocenters of many microearthquakes, we have inferred the joint patterns in the rock. We observed that microearthquake locations do not define a simple, thin, planar distribution, that the fault plane solutions are consistent with shear slippage, and that spectral analysis indicates that the source dimensions and slip along the faults are small. Hence we believe that the microearthquakes result from slip along preexisting joints, and not from tensile extension at the tip of the fracture. Orientations of the principal stresses can be estimated by using fault plane solutions of the larger microearthquakes. By using a joint earthquake location scheme, and/or calibrations with downhole detonators, rock velocities and heterogeneities thereof can be investigated in rock volumes that are far enough from the borehole to be representative of intrincis rock properties.

  6. 液力透平非定常压力脉动的数值计算与分析%Simulation and analysis of unsteady pressure fluctuation in hydraulic turbine

    Institute of Scientific and Technical Information of China (English)

    杨孙圣; 孔繁余; 张新鹏; 黄志攀; 成军

    2012-01-01

    液力透平内部流场的非定常压力脉动是影响机组运行稳定性的关键因素之一,为了研究液力透平内部压力脉动,采用流场分析软件CFX对液力透平内部流场进行了三维非定常数值模拟,通过设置监测点,得到了不同位置处的压力脉动结果,并对压力脉动进行了频域分析.结果表明,液力透平内部压力沿着流道逐渐减弱;蜗壳环形部分入口位置和割舍处压力脉动较小,割舍前端和蜗壳中部位置处压力脉动较大,压力脉动主频为转频的2倍;叶轮内部的压力脉动在液力透平各过流部件的脉动中最为强烈,最大压力脉动发生在叶轮中间位置,压力脉动主频为叶频的2倍;尾水管内的压力脉动沿着尾水管流道逐渐减弱,压力脉动主频与蜗壳内部的压力脉动主频相同,为转频的2倍.%Pressure pulsation of internal flow field within pump as turbine is one of the major factors affecting the stability of turbine unit. To research the unsteady pressure field in pump as turbine, computational fluid dynamics software CFX was adopted in the unsteady flow field analysis. Pressure pulsation results at various monitoring points were acquired and frequency analyses were performed based on these results. Results show that the pressure value decreases along the flow channel of hydraulic turbine. The pressure pulsations at volute cut water and the inlet of volute spiral development part are small. The main frequency of pressure pulsation in volute is two times of the impeller rotational frequency. The most intensive pressure pulsation of hydraulic part in hydraulic turbine is impeller and the most intensive location happens at the middle of impeller passage. The main frequency of impeller pressure pulsation is two times of the blade passing frequency. The pressure pulsation in outlet pipe gradually decreases along the pipe, and its main frequency of pressure pulsation is two times of the impeller rotational

  7. Holographic fluid with bulk viscosity, perturbation of pressure and energy density at finite cutoff surface in the Einstein gravity

    CERN Document Server

    Hu, Ya-Peng; Wu, Xiao-Ning

    2014-01-01

    Using the gravity/fluid correspondence in our paper, we investigate the holographic fluid at finite cutoff surface in the Einstein gravity. After constructing the first order perturbative solution of the Schwarzschild-AdS black brane solution in the Einstein gravity, we focus on the stress-energy tensor of the dual fluid with transport coefficients at the finite cutoff surface. Besides the pressure and energy density of dual fluid are obtained, the shear viscosity is also obtained. The most important results are that we find that if we adopt different conditions to fix the undetermined parameters contained in the stress-energy tensor of the dual fluid, the pressure and energy density of the dual fluid can be perturbed. Particularly, the bulk viscosity of the dual fluid can also be given in this case.

  8. Numerical simulation of hydraulic fracturing using a three-dimensional fracture model coupled with an adaptive mesh fluid model

    NARCIS (Netherlands)

    Xiang, G.L.; Vire, A.; Pavlidis, D.; Pain, C.

    2015-01-01

    A three-dimensional fracture model developed in the context of the combined finite-discrete element method is incorporated into a two-way fluid-solid coupling model. The fracture model is capable of simulating the whole fracturing process. It includes pre-peak hardening deformation, post-peak strain

  9. 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.

  10. Advanced fluid modeling and PIC/MCC simulations of low-pressure ccrf discharges

    Science.gov (United States)

    Becker, M. M.; Kählert, H.; Sun, A.; Bonitz, M.; Loffhagen, D.

    2017-04-01

    Comparative studies of capacitively coupled radio-frequency discharges in helium and argon at pressures between 10 and 80 Pa are presented applying two different fluid modeling approaches as well as two independently developed particle-in-cell/Monte Carlo collision (PIC/MCC) codes. The focus is on the analysis of the range of applicability of a recently proposed fluid model including an improved drift-diffusion approximation for the electron component as well as its comparison with fluid modeling results using the classical drift-diffusion approximation and benchmark results obtained by PIC/MCC simulations. Main features of this time- and space-dependent fluid model are given. It is found that the novel approach shows generally quite good agreement with the macroscopic properties derived by the kinetic simulations and is largely able to characterize qualitatively and quantitatively the discharge behavior even at conditions when the classical fluid modeling approach fails. Furthermore, the excellent agreement between the two PIC/MCC simulation codes using the velocity Verlet method for the integration of the equations of motion verifies their accuracy and applicability.

  11. Failure analysis of fire resistant fluid (FRF piping used in hydraulic control system at oil-fired thermal power generation plant

    Directory of Open Access Journals (Sweden)

    Muhammad Akram

    2017-04-01

    Full Text Available This is a case study regarding frequent forced outages in an oil-fired power generating station due to failure of fire resistant fluid (FRF piping of material ASTM A-304. This analysis was done to find out the most probable cause of failure and to rectify the problem. Methods for finding and analyzing the cracks include nondestructive testing techniques such as visual testing (VT and dye penetrant testing (PT along with that periodic monitoring after rectification of problem. The study revealed that pitting and pit to crack transitions were formed in stainless steel piping containing high pressure (system pressure 115 bars fire resistant fluid. However, after replacement of piping the pitting and cracking reoccurred. It was observed that due to possible exposure to chlorinated moisture in surrounding environment pitting was formed which then transformed into cracks. The research work discussed in this paper illustrates the procedure used in detection of the problem and measures taken to solve the problem.

  12. Pressure distribution in an electrical conducting fluid in spherical form in the presence of crossed electrical and magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Shchelukhin, E.M.; Tsarevskaya, I.I.; Bruskii, V.P.

    1977-01-01

    An examination is made of electromagnetic forces in an isotropic fluid having a spherical form with non-conducting walls in the presence of crossed electrical and magnetic fields. The problem was solved on the assumption that the fluid is in a quiescent state but that the magnetic field is uniform. Computations were made of static pressure distribution and the scalar potential of an electromagnetic field in a fluid. Experimental data are presented on the measurement of static pressure distributions which agree well with the theoretical calculations. The obtained results may be used for engineering estimates of pressure in technological MHD apparatus.

  13. Effect of Natural Fractures on Hydraulic Fracturing

    Science.gov (United States)

    Ben, Y.; Wang, Y.; Shi, G.

    2012-12-01

    Hydraulic Fracturing has been used successfully in the oil and gas industry to enhance oil and gas production in the past few decades. Recent years have seen the great development of tight gas, coal bed methane and shale gas. Natural fractures are believed to play an important role in the hydraulic fracturing of such formations. Whether natural fractures can benefit the fracture propagation and enhance final production needs to be studied. Various methods have been used to study the effect of natural fractures on hydraulic fracturing. Discontinuous Deformation Analysis (DDA) is a numerical method which belongs to the family of discrete element methods. In this paper, DDA is coupled with a fluid pipe network model to simulate the pressure response in the formation during hydraulic fracturing. The focus is to study the effect of natural fractures on hydraulic fracturing. In particular, the effect of rock joint properties, joint orientations and rock properties on fracture initiation and propagation will be analyzed. The result shows that DDA is a promising tool to study such complex behavior of rocks. Finally, the advantages of disadvantages of our current model and future research directions will be discussed.

  14. Influence of fluid pore pressure on chaotic sliding of tectonic faults

    Science.gov (United States)

    Turuntaev, Sergey; Riga, Vasily

    2016-04-01

    The problem of permeable rock pore pressure variation influence on tectonic fault sliding and generation of seismic events was studied in the scope of rate-and-state friction model with two-parametric friction law. The coupled problem of pore-elasticity and fault sliding governed by two-parametric rate-and-state equation was studied numerically. The main modes of the fault sliding were found, and transitions from one mode to another due to the fluid pore pressure change were observed. The conditions for transition from stable to chaotic sliding (considered as an analog of seismic event generations) were found. It was shown, that chaotic sliding has features of Poincare stability and can be characterized by finite values of correlation integral and embedding dimension, which depend on critical shear stresses. Change of the effective critical stresses by the pore pressure variation will result in change of the tectonic fault sliding mode and consequently change of the seismic regime.

  15. 46 CFR 28.405 - Hydraulic equipment.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Hydraulic equipment. 28.405 Section 28.405 Shipping... Operate With More Than 16 Individuals on Board § 28.405 Hydraulic equipment. (a) Each hydraulic system... than four times the system maximum operating pressure. (c) Each hydraulic system must be equipped...

  16. Blood viscosity monitoring during cardiopulmonary bypass based on pressure-flow characteristics of a Newtonian fluid.

    Science.gov (United States)

    Okahara, Shigeyuki; Zu Soh; Takahashi, Shinya; Sueda, Taijiro; Tsuji, Toshio

    2016-08-01

    We proposed a blood viscosity estimation method based on pressure-flow characteristics of oxygenators used during cardiopulmonary bypass (CPB) in a previous study that showed the estimated viscosity to correlate well with the measured viscosity. However, the determination of the parameters included in the method required the use of blood, thereby leading to high cost of calibration. Therefore, in this study we propose a new method to monitor blood viscosity, which approximates the pressure-flow characteristics of blood considered as a non-Newtonian fluid with characteristics of a Newtonian fluid by using the parameters derived from glycerin solution to enable ease of acquisition. Because parameters used in the estimation method are based on fluid types, bovine blood parameters were used to calculate estimated viscosity (ηe), and glycerin parameters were used to estimate deemed viscosity (ηdeem). Three samples of whole bovine blood with different hematocrit levels (21.8%, 31.0%, and 39.8%) were prepared and perfused into the oxygenator. As the temperature changed from 37 °C to 27 °C, the oxygenator mean inlet pressure and outlet pressure were recorded for flows of 2 L/min and 4 L/min, and the viscosity was estimated. The value of deemed viscosity calculated with the glycerin parameters was lower than estimated viscosity calculated with bovine blood parameters by 20-33% at 21.8% hematocrit, 12-27% at 31.0% hematocrit, and 10-15% at 39.8% hematocrit. Furthermore, deemed viscosity was lower than estimated viscosity by 10-30% at 2 L/min and 30-40% at 4 L/min. Nevertheless, estimated and deemed viscosities varied with a similar slope. Therefore, this shows that deemed viscosity achieved using glycerin parameters may be capable of successfully monitoring relative viscosity changes of blood in a perfusing oxygenator.

  17. Pulse-pressure variation predicts fluid responsiveness during heart displacement for off-pump coronary artery bypass surgery.

    Science.gov (United States)

    Lee, Jong-Hwan; Jeon, Yunseok; Bahk, Jae-Hyon; Gil, Nam-Su; Kim, Ki-Bong; Hong, Deok Man; Kim, Hyun Joo

    2011-12-01

    The aim of this study was to evaluate the ability of pulse-pressure variation to predict fluid responsiveness during heart displacement for off-pump coronary artery bypass surgery using receiver operating characteristic analysis. A prospective study. A clinical study in a single cardiac anesthesia institution. Thirty-five patients undergoing elective off-pump coronary artery bypass surgery. Central venous pressure, pulmonary arterial occlusion pressure, pulse-pressure variation, and cardiac index were measured 5 minutes after revascularization of the left anterior descending coronary artery and before heart displacement. Immediately after heart displacement for revascularization of the left circumflex artery, and 10 minutes after fluid loading with hydroxyethyl starch 6% (10 mL/kg) during heart displacement, the measurements were repeated. Patients whose cardiac indices increased by ≥15% from fluid loading were defined as responders. After heart displacement, only pulse-pressure variation showed significant difference between the responders and nonresponders (13.48 ± 6.42 v 7.33 ± 3.81, respectively; p fluid responsiveness (area under the curve = 0.839, p = 0.0001). Pulse-pressure variation >7.69% identified the responders, with a sensitivity of 86% and a specificity of 83%. Pulse-pressure variation successfully predicted fluid responsiveness and would be useful in guiding fluid management during heart displacement for off-pump coronary artery bypass surgery. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. 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...

  19. Numerical Study on the Permeability of the Hydraulic-Stimulated Fracture Network in Naturally-Fractured Shale Gas Reservoirs

    Directory of Open Access Journals (Sweden)

    Zhaobin Zhang

    2016-09-01

    Full Text Available As hydraulic fracturing is a fluid-rock coupling process, the permeability of the hydraulic-stimulated fracture network in the initial stage has great effects on the propagation of the hydraulic fracture network in the following stages. In this work, the permeability of the hydraulic-stimulated fracture network in shale gas reservoirs is investigated by a newly-proposed model based on the displacement discontinuity method. The permeability of the fracture network relies heavily on fracture apertures, which can be calculated with high precision by the displacement discontinuity method. The hydraulic fracturing processes are simulated based on the natural fracture networks reconstructed from the shale samples in the Longmaxi formation of China. The flow fields are simulated and the permeability is calculated based on the fracture configurations and fracture apertures after hydraulic fracturing treatment. It is found that the anisotropy of the permeability is very strong, and the permeability curves have similar shapes. Therefore, a fitting equation of the permeability curve is given for convenient use in the future. The permeability curves under different fluid pressures and crustal stress directions are obtained. The results show that the permeability anisotropy is stronger when the fluid pressure is higher. Moreover, the permeability anisotropy reaches the minimum value when the maximum principle stress direction is perpendicular to the main natural fracture direction. The investigation on the permeability is useful for answering how the reservoirs are hydraulically stimulated and is useful for predicting the propagation behaviors of the hydraulic fracture network in shale gas reservoirs.

  20. Low-power microfluidic electro-hydraulic pump (EHP).

    Science.gov (United States)

    Lui, Clarissa; Stelick, Scott; Cady, Nathaniel; Batt, Carl

    2010-01-07

    Low-power electrolysis-based microfluidic pumps utilizing the principle of hydraulics, integrated with microfluidic channels in polydimethylsiloxane (PDMS) substrates, are presented. The electro-hydraulic pumps (EHPs), consisting of electrolytic, hydraulic and fluidic chambers, were investigated using two types of electrodes: stainless steel for larger volumes and annealed gold electrodes for smaller-scale devices. Using a hydraulic fluid chamber and a thin flexible PDMS membrane, this novel prototype successfully separates the reagent fluid from the electrolytic fluid, which is particularly important for biological and chemical applications. The hydraulic advantage of the EHP device arises from the precise control of flow rate by changing the electrolytic pressure generated, independent of the volume of the reagent chamber, mimicking the function of a hydraulic press. Since the reservoirs are pre-filled with reagents and sealed prior to testing, external fluid coupling is minimized. The stainless steel electrode EHPs were manufactured with varying chamber volume ratios (1 : 1 to 1 : 3) as a proof-of-concept, and exhibited flow rates of 1.25 to 30 microl/min with electrolysis-based actuation at 2.5 to 10 V(DC). The miniaturized gold electrode EHPs were manufactured with 3 mm diameters and 1 : 1 chamber volume ratios, and produced flow rates of 1.24 to 7.00 microl/min at 2.5 to 10 V(AC), with a higher maximum sustained pressure of 343 KPa, suggesting greater device robustness using methods compatible with microfabrication. The proposed technology is low-cost, low-power and disposable, with a high level of reproducibility, allowing for ease of fabrication and integration into existing microfluidic lab-on-a-chip and analysis systems.

  1. 心墙水力劈裂与孔压关系的探讨%The analysis of the relationship between hydraulic fracture and the pore pressure

    Institute of Scientific and Technical Information of China (English)

    张红日; 党发宁; 兰素恋; 魏见海

    2012-01-01

    基于Biot固结理论的有效应力二维数值模拟方法,研究了堆石坝的粘土心墙水力劈裂过程中孔隙水压力的变化.分析了坝体竣工期粘土心墙中的拱效应,探讨了从竣工固结到蓄水过程和稳定渗流期粘土心墙中孔隙水压力的变化分布特点,并对心墙发生水力劈裂的可能性进行判断.研究结果表明:堆石坝粘土心墙内部孔隙水压力梯度的模拟分析能更加合理地解释水力劈裂发生与蓄水速度和心墙低渗透性的关系,因此,分析考虑水位上升过程中粘土心墙内孔隙水压力分布情况是研究心墙水力劈裂发生机理的重点.%Based on the consolidation theory of Biot effective stress analysis method, two-dimensional numerical simulation is adopted to study the dam from the completion of the dam to the clay core run-time pore pressure changes in the process. Arching effect of the completion period and the changes with the completion of the process of consolidation on the stability of the water flow in the pore water pressure distribution are analyzed based on the analysis of clay core dams, the mechanism of hydraulic fracture on the basis of the core wall of the dam occurred in the hydraulic is determined with the possibility of splitting. The results show that the simulation of gradient internal pore water pressure for the clay core of rockfilled dam core can reasonably explain the occurrence of hydraulic fracturing with water speed, and the low permeability of the core wall has great effects. When hydraulic fracture occurred with the core wall mechanism of the core wall, the distribution of clay pore water pressure must be taken into account.

  2. Simultaneous determination of capillary pressure and relative permeability curves from core-flooding experiments with various fluid pairs

    National Research Council Canada - National Science Library

    Ronny Pini; Sally M Benson

    2013-01-01

      Capillary pressure and relative permeability drainage curves are simultaneously measured on a single Berea Sandstone core by using three different fluid pairs, namely g CO 2/water, g N 2/water and s c CO 2/brine...

  3. Computational evaluation of intraventricular pressure gradients based on a fluid-structure approach.

    Science.gov (United States)

    Redaelli, A; Montevecchi, F M

    1996-11-01

    The dynamics of intraventricular blood flow, i.e. its rapid evolution, implies the rise of intraventricular pressure gradients (IPGs) characteristic of the inertia-driven events as experimentally observed by Pasipoularides (1987, 1990) and by Falsetti et al. (1986). The IPG time course is determined by the wall contraction which, in turn, depends on the load applied, namely the intraventricular pressure which is the sum of the aortic pressure (i.e., the systemic net response) and the IPG. Hence the IPGs account, at least in part, for the wall movement. These considerations suggest the necessity of a comprehensive analysis of the ventricular mechanics involving both ventricular wall mechanics and intraventricular fluid dynamics as each domain determines the boundary conditions of the other. This paper presents a computational approach to ventricular ejection mechanics based on a fluid-structure interaction calculation for the evaluation of the IPG time course. An axisymmetric model of the left ventricle is utilized. The intraventricular fluid is assumed to be Newtonian. The ventricle wall is thin and is composed of two sets of counter-rotating fibres which behave according to the modified version of Wong's sarcomere model proposed by Montevecchi and Pietrabissa and Pietrabissa et al. (1987, 1991). The full Navier-Stokes equations describing the fluid domain are solved using Galerkin's weighted residual approach in conjunction with finite element approximation (FIDAP). The wall displacement is solved using the multiplane quasi-Newton method proposed by Buzzi Ferraris and Tronconi (1985). The interaction procedure is performed by means of an external macro which compares the flow fields and the wall displacement and appropriately modifies the boundary conditions to reach the simultaneous and congruous convergence of the two problems. The results refer to a simulation of the ventricular ejection with a heart rate of 72 bpm. In this phase the ventricle ejects 61 cm3

  4. Remotely Adjustable Hydraulic Pump

    Science.gov (United States)

    Kouns, H. H.; Gardner, L. D.

    1987-01-01

    Outlet pressure adjusted to match varying loads. Electrohydraulic servo has positioned sleeve in leftmost position, adjusting outlet pressure to maximum value. Sleeve in equilibrium position, with control land covering control port. For lowest pressure setting, sleeve shifted toward right by increased pressure on sleeve shoulder from servovalve. Pump used in aircraft and robots, where hydraulic actuators repeatedly turned on and off, changing pump load frequently and over wide range.

  5. Hydraulic supports for polishing TMT M3MP

    Science.gov (United States)

    Hu, Haifei; Qi, Erhui; Cole, Glen; Hu, Haixiang; Luo, Xiao; Ford, Virginia; Zhang, Xuejun

    2016-10-01

    For polishing the ultra-thin TMT M3MP, a polishing support system with 18 hydraulic supports (HS) is introduced. This work focuses on the designing and testing of these HSs. Firstly the design concept of HS system is discussed; then mechanical implementation of the HS structure is carried out, with special consideration of fluid cycling, work pressurization and the weight component. Afterward the piping installation and the de-gas process for the working fluid are implemented. Pressurization and stiffness are well checked before system integration for the single HS unit. Finally the support system is integrated for the polishing process.

  6. Numerical Simulations of an atmospheric pressure discharge using a two dimensional fluid model

    Science.gov (United States)

    Iqbal, Muhammad M.; Turner, Miles M.

    2008-10-01

    We present numerical simulations of a parallel-plate dielectric barrier discharge using a two-dimensional fluid model with symmetric boundary conditions in pure helium and He-N2 gases at atmospheric pressure. The periodic stationary pattern of electrons and molecular helium ions density is shown at different times during one breakdown pulse for the pure helium gas. The temporal behavior of the helium metastables and excimers species density is examined and their influences on the discharge characteristics are exhibited for an APD. The atmospheric pressure discharge modes (APGD and APTD) are affected with small N2 impurities and the discharge mode structures are described under different operating conditions. The uniform and filamentary behavior of the discharge is controlled with the variable relative permittivity of the dielectric barrier material. The influence of nitrogen impurities plays a major role for the production of the filaments in the after glow phase of He-N2 discharge and the filaments are clearly observed with the increased recombination coefficient of nitrogen ions. The creation and annihilation mechanism of filaments is described with the production and destruction of nitrogen ions at different applied voltages and driving frequencies for a complete cycle. The results of the fluid model are validated by comparison with the experimental atmospheric pressure discharge results in He-N2 plasma discharge.

  7. Non-Newtonian fluids: Frictional pressure loss prediction for fully-developed flow in straight pipes

    Science.gov (United States)

    1991-10-01

    ESDU 91025 discusses models used to describe the rheology of time independent pseudohomogeneous non-Newtonian fluids (power-law, Bingham, Herschel-Bulkley and a generalized model due to Metzner and Reed); they are used to calculate the laminar flow pressure drop (which is independent of pipe roughness in this regime). Values of a generalized Reynolds number are suggested to define transitional and turbulent flow. For turbulent flow in smooth pipes, pressure loss is estimated on the basis of an experimentally determined rheogram using either the Dodge-Metzner or Bowen approach depending on the available measurements. Bowen requires results for at least two pipe diameters. The choice of Dodge-Metzner when data are limited is discussed; seven possible methods are assessed against five sets of experimental results drawn from the literature. No method is given for transitional flow, which it is suggested should be avoided, but the turbulent correlation is recommended because it will yield an overestimate. Suggestions are made for the treatment of roughness effects. Several worked examples illustrate the use of the methods and a flowchart guides the user through the process from experimentally characterizing the behavior of the fluid to determining the pressure drop. A computer program, ESDUpac A9125, is also provided.

  8. Numerical Modeling and Investigation of Fluid-Driven Fracture Propagation in Reservoirs Based on a Modified Fluid-Mechanically Coupled Model in Two-Dimensional Particle Flow Code

    Directory of Open Access Journals (Sweden)

    Jian Zhou

    2016-09-01

    Full Text Available Hydraulic fracturing is a useful tool for enhancing rock mass permeability for shale gas development, enhanced geothermal systems, and geological carbon sequestration by the high-pressure injection of a fracturing fluid into tight reservoir rocks. Although significant advances have been made in hydraulic fracturing theory, experiments, and numerical modeling, when it comes to the complexity of geological conditions knowledge is still limited. Mechanisms of fluid injection-induced fracture initiation and propagation should be better understood to take full advantage of hydraulic fracturing. This paper presents the development and application of discrete particle modeling based on two-dimensional particle flow code (PFC2D. Firstly, it is shown that the modeled value of the breakdown pressure for the hydraulic fracturing process is approximately equal to analytically calculated values under varied in situ stress conditions. Furthermore, a series of simulations for hydraulic fracturing in competent rock was performed to examine the influence of the in situ stress ratio, fluid injection rate, and fluid viscosity on the borehole pressure history, the geometry of hydraulic fractures, and the pore-pressure field, respectively. It was found that the hydraulic fractures in an isotropic medium always propagate parallel to the orientation of the maximum principal stress. When a high fluid injection rate is used, higher breakdown pressure is needed for fracture propagation and complex geometries of fractures can develop. When a low viscosity fluid is used, fluid can more easily penetrate from the borehole into the surrounding rock, which causes a reduction of the effective stress and leads to a lower breakdown pressure. Moreover, the geometry of the fractures is not particularly sensitive to the fluid viscosity in the approximate isotropic model.

  9. Chronic elevation of pulmonary microvascular pressure in chronic heart failure reduces bi-directional pulmonary fluid flux.

    Science.gov (United States)

    Dixon, Dani-Louise; Mayne, George C; Griggs, Kim M; De Pasquale, Carmine G; Bersten, Andrew D

    2013-04-01

    Chronic heart failure leads to pulmonary vascular remodelling and thickening of the alveolar-capillary barrier. We examined whether this protective effect may slow resolution of pulmonary oedema consistent with decreased bi-directional fluid flux. Seven weeks following left coronary artery ligation, we measured both fluid flux during an acute rise in left atrial pressure (n = 29) and intrinsic alveolar fluid clearance (n = 45) in the isolated rat lung. Chronic elevation of pulmonary microvascular pressure prevented pulmonary oedema and decreased lung compliance when left atrial pressure was raised to 20 cmH2O, and was associated with reduced expression of endothelial aquaporin 1 (P = 0.03). However, no other changes were found in mediators of fluid flux or cellular fluid channels. In isolated rat lungs, chronic LV dysfunction (LV end-diastolic pressure and infarct circumference) was also inversely related to alveolar fluid clearance (P ≤ 0.001). The rate of pulmonary oedema reabsorption was estimated by plasma volume expansion in eight patients with a previous clinical history of chronic heart failure and eight without, who presented with acute pulmonary oedema. Plasma volume expansion was reduced at 24 h in those with chronic heart failure (P = 0.03). Chronic elevation of pulmonary microvascular pressure in CHF leads to decreased intrinsic bi-directional fluid flux at the alveolar-capillary barrier. This adaptive response defends against alveolar flooding, but may delay resolution of alveolar oedema.

  10. Low pressure corium dispersion experiments in the DISCO test facility with cold simulant fluids

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, L.; Gargallo, M.; Kirstahler, M.; Schwall, M.; Wachter, E.; Woerner, G.

    2006-08-15

    In a severe accident special pressure relief valves in the primary circuit of German Pressurized Water Reactors (PWR) will transfer a high pressure accident into a low pressure scenario. However, there may be a time window during late in-vessel reflooding scenarios where the pressure is in the order of 1 or 2 MPa at the moment of the reactor vessel rupture. A failure in the bottom head of the reactor pressure vessel, followed by melt expulsion and blowdown of the reactor cooling system, might disperse molten core debris out of the reactor pit, even at such low pressures. The mechanisms of efficient debris-to-gas heat transfer, exothermic metal/oxygen reactions, and hydrogen combustion may cause a rapid increase in pressure and temperature in the reactor containment. Integral experiments are necessary to furnish data for modeling these processes in computer codes, that will be used to apply these result to the reactor case. The acquired knowledge can lead to realize additional safety margins for existing or future plants. The test facility DISCO-C (DIspersion of Simulant COrium - Cold) models the annular reactor cavity and the subcompartments of a large European reactor in a scale 1:18. The fluid dynamics of the dispersion process was studied using model fluids, water or bismuth alloy instead of corium, and nitrogen or helium instead of steam. The effects of different breach sizes and locations, and different failure pressures on the dispersion were studied, specifically by testing central holes, lateral holes, horizontal rips, and complete ripping of the bottom head. 22 experiments were performed in a basic cavity geometry with holes at the bottom of the lower head to study the similarity relations. Variables were the hole diameter, the initial pressure in the RPV and the fluids used. The only flow path out of the reactor pit was the annular gap between the inner wall of the reactor pit and the RPV, and then along the main coolant lines into the subcompartments

  11. Final report on supplementary comparison APMP.M.P-S7.TRI in hydraulic gauge pressure from 40 MPa to 200 MPa

    Science.gov (United States)

    Kobata, Tokihiko; Olson, Douglas A.; Eltawil, Alaaeldin A.

    2017-01-01

    This report describes the results of a supplementary comparison of hydraulic high-pressure standards at three national metrology institutes (NMIs); National Metrology Institute of Japan, AIST (NMIJ/AIST), National Institute of Standards and Technology (NIST), USA and National Institute for Standards (NIS), Egypt, which was carried out at NIST during the period May 2001 to September 2001 within the framework of the Asia-Pacific Metrology Programme (APMP) in order to evaluate their degrees of equivalence at pressures in the range 40 MPa to 200 MPa for gauge mode. The pilot institute was NMIJ/AIST. Three working pressure standards from the institutes, in the form of piston-cylinder assemblies, were used for the comparison. The comparison and calculation methods used are discussed in this report. From the cross-float measurements, the differences between the working pressure standards of each institute were examined through an evaluation of the effective area of each piston-cylinder assembly with its uncertainty. From the comparison results, it was revealed that the values claimed by the participating institutes, NMIJ, NIST, and NIS, agree within the expanded (k = 2) uncertainties. The hydraulic pressure standards in the range 40 MPa to 200 MPa for gauge mode of the three participating NMIs were found to be equivalent within their claimed uncertainties. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. The viscosity and density of sour gas fluids at high temperatures and high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Giri, B.R.; Marriott, R.A.; Blais, P.; Clark, P.D. [Alberta Sulphur Research Ltd., Calgary, AB (Canada); Calgary Univ., AB (Canada). Dept. of Chemistry

    2010-01-15

    This poster session discussed an experiment designed to measure the viscosity and density of sour gas fluids at high temperatures and pressures. An option for disposing acid gases while enhancing the production of oil and gas fields is the re-injection of gases rich in hydrogen sulphide/carbon dioxide (H{sub 2}S/CO{sub 2}) into reservoirs up to very high pressures, but issues with respect to corrosion, compression, pumping, and transport need addressing, and the reliable high-density/high-pressure data needed to arrive at an optimum process concept and the design of pumps, compressors, and transport lines had up to this point been lacking. The experimental set up involved the use of a Vibrating Tube Densimeter and a Cambridge Viscometer. Working with toxic gases at very high pressures and obtaining highly accurate data in a wide range of conditions were two of the challenges faced during the experiment. The experiment resulted in physical property measurement systems being recalibrated and a new daily calibration routine being adopted for accuracy. The densities and viscosities of pure CO{sub 2} and sulphur dioxide (SO{sub 2}) in a wide pressure and temperature range were determined. 1 tab., 9 figs.

  13. Stem Hydraulic Conductivity depends on the Pressure at Which It Is Measured and How This Dependence Can Be Used to Assess the Tempo of Bubble Pressurization in Recently Cavitated Vessels1[OPEN

    Science.gov (United States)

    Liu, Jinyu; Tyree, Melvin T.

    2015-01-01

    Cavitation of water in xylem vessels followed by embolism formation has been authenticated for more than 40 years. Embolism formation involves the gradual buildup of bubble pressure (air) to atmospheric pressure as demanded by Henry’s law of equilibrium between gaseous and liquid phases. However, the tempo of pressure increase has not been quantified. In this report, we show that the rate of pressurization of embolized vessels is controlled by both fast and slow kinetics, where both tempos are controlled by diffusion but over different spatial scales. The fast tempo involves a localized diffusion from endogenous sources: over a distance of about 0.05 mm from water-filled wood to the nearest embolized vessels; this process, in theory, should take 17 h, with complete equilibrium requiring 1 to 2 d. The implications of these timescales for the standard methods of measuring percentage loss of hydraulic conductivity are discussed in theory and deserve more research in future. PMID:26468516

  14. Gravity-Driven Hydraulic Fractures

    Science.gov (United States)

    Germanovich, L. N.; Garagash, D.; Murdoch, L. C.; Robinowitz, M.

    2014-12-01

    This study is motived by a new method for disposing of nuclear waste by injecting it as a dense slurry into a hydraulic fracture that grows downward to great enough depth to permanently isolate the waste. Disposing of nuclear waste using gravity-driven hydraulic fractures is mechanically similar to the upward growth of dikes filled with low density magma. A fundamental question in both applications is how the injected fluid controls the propagation dynamics and fracture geometry (depth and breadth) in three dimensions. Analog experiments in gelatin [e.g., Heimpel and Olson, 1994; Taisne and Tait, 2009] show that fracture breadth (the short horizontal dimension) remains nearly stationary when the process in the fracture "head" (where breadth is controlled) is dominated by solid toughness, whereas viscous fluid dissipation is dominant in the fracture tail. We model propagation of the resulting gravity-driven (buoyant or sinking), finger-like fracture of stationary breadth with slowly varying opening along the crack length. The elastic response to fluid loading in a horizontal cross-section is local and can be treated similar to the classical Perkins-Kern-Nordgren (PKN) model of hydraulic fracturing. The propagation condition for a finger-like crack is based on balancing the global energy release rate due to a unit crack extension with the rock fracture toughness. It allows us to relate the net fluid pressure at the tip to the fracture breadth and rock toughness. Unlike the PKN fracture, where breadth is known a priori, the final breadth of a finger-like fracture is a result of processes in the fracture head. Because the head is much more open than the tail, viscous pressure drop in the head can be neglected leading to a 3D analog of Weertman's hydrostatic pulse. This requires relaxing the local elasticity assumption of the PKN model in the fracture head. As a result, we resolve the breadth, and then match the viscosity-dominated tail with the 3-D, toughness

  15. INFLUENCES OF HYDRAULIC UPLIFT PRESSURES ON STABILITY OF GRAVITY DAM%坝底水浮力对重力坝稳定性的影响分析

    Institute of Scientific and Technical Information of China (English)

    UTILI Stefano; 尹振宇; 蒋明镜

    2008-01-01

    着重研究一个典型的混凝土重力坝的坝底水浮力对大坝稳定性的影响,此大坝位于意大利的Cumbidanovu岛.大坝的基础由含有高度开裂的岩石所构成.首先,通过把大坝视为自由体的平衡分析法来评价大坝破坏前的最大水压力和有效排水系统对大坝稳定性的影响.然后,使用离散元方法来进一步评价开裂基岩中的水流状态,得到该水流产生的浮托力的分布,最终得到此水浮力对大坝稳定性的影响.对设计而言,上述分析考虑了岩基渗透,运用离散元方法进行模拟.研究结果表面,相比保守的平衡分析法,此模型可以得到更大的水浮力荷载.%A study of the influences of the hydraulic uplift pressures underneath the base of a typical concrete gravity dam on its stability is presented. The dam is located at Cumbidanovu(Sardegna,Italy). The foundation of the dam is made of heavily fractured rock. Firstly,analytical calculations about the equilibrium of the dam as a free body have been employed to evaluate the maximum hydraulic pressure before collapsing and to assess the impact of an effective drainage system on the stability of the dam in a simple way. Secondly,numerical analyses by the distinct element method(DEM) using the code UDEC have been carried out to evaluate the hydraulic flow taking place within the fractured rock foundation,the uplift pressure distribution generated by the calculated flow,and its influence on the stability of the dam. For design purposes,it emerges that availability of reliable data on the hydraulic permeability of rock foundations and a computationally advanced distinct element modeling might lead to the acceptance of loads significantly higher than the more conservative estimations obtained from equilibrium analyses.

  16. 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...

  17. Kinetic theory for nongeodesic particle motion Selfinteracting equilibrium states and effective viscous fluid pressures

    CERN Document Server

    Zimdahl, W; Zimdahl, Winfried; Balakin, Alexander B.

    1998-01-01

    The particles of a classical relativistic gas are supposed to move under the influence of a quasilinear (in the particle four-momenta), self-interacting force inbetween elastic, binary collisions. This force which is completely fixed by the equilibrium conditions of the gas, gives rise to an effective viscous pressure on the fluid phenomenological level. Earlier results concerning the possibility of accelerated expansion of the universe due to cosmological particle production are reinterpreted. A phenomenon such as power law inflation may be traced back to specific self-interacting forces keeping the particles of a gas universe in states of generalized equilibrium.

  18. CABARET scheme in velocity-pressure formulation for two-dimensional incompressible fluids

    Science.gov (United States)

    Glotov, V. Yu.; Goloviznin, V. M.

    2013-06-01

    The CABARET method was generalized to two-dimensional incompressible fluids in terms of velocity and pressure. The resulting algorithm was verified by computing the transport and interaction of various vortex structures: a stationary and a moving solitary vortex, Taylor-Green vortices, and vortices formed by the instability of double shear layers. Much attention was also given to the modeling of homogeneous isotropic turbulence and to the analysis of its spectral properties. It was shown that, regardless of the mesh size, the slope of the energy spectra up to the highest-frequency harmonics is equal -3, which agrees with Batchelor's enstrophy cascade theory.

  19. Establishment of digital model for dynamic simulation analysis on hydraulic impact perforator

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Hydraulic impact perforator is powerful tools for trenchless project. It has advantages in cabinet structure, low cost, long life and easy protected. Compared with pneumatic DTH, the hydraulic impact spear worked under high pressure and using uncompressible fluid thusgreater impact energy and higher efficiency can be supported. The authors founded the dynamic simulation model of HDI-146 hydraulic impact spear. The project for solving the differential equation was suggested also. By means of virtual machine technology, the dynamic mechanism of HDI-146 can be explored and tutoring us to optimize the structural parameters can be made.

  20. Multiplexed hydraulic valve actuation using ionic liquid filled soft channels and Braille displays

    Science.gov (United States)

    Gu, Wei; Chen, Hao; Tung, Yi-Chung; Meiners, Jens-Christian; Takayama, Shuichi

    2007-01-01

    Pneumatic actuation with multilayer soft lithography enables operation of up to thousands of valves in parallel using far fewer control lines. However, it is dependent on macroscopic switches and external pressure sources that require interconnects and limit portability. The authors present a more portable and multiplexed valve actuation strategy that uses a grid of mechanically actuated Braille pins to hydraulically, rather than pneumatically, deform elastic actuation channels that act as valves. Experimental and theoretical analyses show that the key to reliable operation of the hydraulic system is the use of nonvolatile ionic liquids as the hydraulic fluid.

  1. Complete classification of stationary flows with constant total pressure of ideal incompressible infinitely conducting fluid

    CERN Document Server

    Golovin, S V

    2011-01-01

    The exhaustive classification of stationary incompressible flows with constant total pressure of ideal infinitely electrically conducting fluid is given. By introduction of curvilinear coordinates based on streamlines and magnetic lines of the flow the system of magnetohydrodynamics (MHD) equations is reduced to a nonlinear vector wave equation extended by the incompressibility condition in a form of a generalized Cauchy integral. For flows with constant total pressure the wave equation is explicitly integrated, whereas the incompressibility condition is reduced to a scalar equation for functions, depending on different sets of variables. The central difficulty of the investigation is the separation of variables in the scalar equation, and integration of the resulting overdetermined systems of nonlinear partially differential equations. The canonical representatives of all possible types of solutions together with equivalence transformations, that extend the canonical set to the whole amount of solutions are ...

  2. Isobaric thermal expansivity behaviour against temperature and pressure of associating fluids

    Energy Technology Data Exchange (ETDEWEB)

    Navia, Paloma; Troncoso, Jacobo [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, Campus As Lagoas, 32004 Ourense (Spain); Romani, Luis, E-mail: romani@uvigo.e [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, Campus As Lagoas, 32004 Ourense (Spain)

    2010-01-15

    In order to study the influence of association on the isobaric thermal expansivity, this magnitude has been experimentally determined for a set of associating fluids within the temperature and pressure intervals (278.15 to 348.15) K and (5 to 55) MPa by means of calorimetric measurements. The 1-alcohol series, from methanol to 1-decanol, 2-pentanol, 3-pentanol, and 1-pentylamine were selected. With a view on checking the quality of the experimental data, they are compared with available literature values; good coherence was obtained for most of the studied liquids. The analysis of the experimental results reveals that the association capability presents a strong influence not only on the value of the isobaric thermal expansivity itself, but also on its behaviour against temperature and pressure.

  3. Helical coil thermal hydraulic model

    Science.gov (United States)

    Caramello, M.; Bertani, C.; De Salve, M.; Panella, B.

    2014-11-01

    A model has been developed in Matlab environment for the thermal hydraulic analysis of helical coil and shell steam generators. The model considers the internal flow inside one helix and its associated control volume of water on the external side, both characterized by their inlet thermodynamic conditions and the characteristic geometry data. The model evaluates the behaviour of the thermal-hydraulic parameters of the two fluids, such as temperature, pressure, heat transfer coefficients, flow quality, void fraction and heat flux. The evaluation of the heat transfer coefficients as well as the pressure drops has been performed by means of the most validated literature correlations. The model has been applied to one of the steam generators of the IRIS modular reactor and a comparison has been performed with the RELAP5/Mod.3.3 code applied to an inclined straight pipe that has the same length and the same elevation change between inlet and outlet of the real helix. The predictions of the developed model and RELAP5/Mod.3.3 code are in fairly good agreement before the dryout region, while the dryout front inside the helical pipes is predicted at a lower distance from inlet by the model.

  4. Analytical solutions for dynamic pressures of coupling fluid-solid-porous medium due to P wave incidence

    Institute of Scientific and Technical Information of China (English)

    王进廷; 张楚汉; 金峰

    2004-01-01

    Wave reflection and refraction in layered media is a topic closely related to seismology, acoustics, geophysics and earthquake engineering. Analytical solutions for wave reflection and refraction coefficients in multi-layered media subjected to P wave incidence from the elastic half-space are derived in terms of displacement potentials. The system is composed of ideal fluid, porous medium, and underlying elastic solid. By numerical examples, the effects of porous medium and the incident wave angle on the dynamic pressures of ideal fluid are analyzed. The results show that the existence of the porous medium, especially in the partially saturated case, may significantly affect the dynamic pressures of the overlying fluid.

  5. Influence of phase connectivity on the relationship among capillary pressure, fluid saturation, and interfacial area in two-fluid-phase porous medium systems

    Science.gov (United States)

    McClure, James E.; Berrill, Mark A.; Gray, William G.; Miller, Cass T.

    2016-09-01

    Multiphase flows in porous medium systems are typically modeled at the macroscale by applying the principles of continuum mechanics to develop models that describe the behavior of averaged quantities, such as fluid pressure and saturation. These models require closure relations to produce solvable forms. One of these required closure relations is an expression relating the capillary pressure to fluid saturation and, in some cases, other topological invariants such as interfacial area and the Euler characteristic (or average Gaussian curvature). The forms that are used in traditional models, which typically consider only the relationship between capillary pressure and saturation, are hysteretic. An unresolved question is whether the inclusion of additional morphological and topological measures can lead to a nonhysteretic closure relation. Relying on the lattice Boltzmann (LB) method, we develop an approach to investigate equilibrium states for a two-fluid-phase porous medium system, which includes disconnected nonwetting phase features. A set of simulations are performed within a random close pack of 1964 spheres to produce a total of 42 908 distinct equilibrium configurations. This information is evaluated using generalized additive models to quantitatively assess the degree to which functional relationships can explain the behavior of the equilibrium data. The variance of various model estimates is computed, and we conclude that, except for the limiting behavior close to a single fluid regime, capillary pressure can be expressed as a deterministic and nonhysteretic function of fluid saturation, interfacial area between the fluid phases, and the Euler characteristic. To our knowledge, this work is unique in the methods employed, the size of the data set, the resolution in space and time, the true equilibrium nature of the data, the parametrizations investigated, and the broad set of functions examined. The conclusion of essentially nonhysteretic behavior provides

  6. Final report on key comparison APMP.M.P-K13 in hydraulic gauge pressure from 50 MPa to 500 MPa

    Science.gov (United States)

    Kajikawa, Hiroaki; Kobata, Tokihiko; Yadav, Sanjay; Jian, Wu; Changpan, Tawat; Owen, Neville; Yanhua, Li; Hung, Chen-Chuan; Ginanjar, Gigin; Choi, In-Mook

    2015-01-01

    This report describes the results of a key comparison of hydraulic high-pressure standards at nine National Metrology Institutes (NMIs: NMIJ/AIST, NPLI, NMC/A*STAR, NIMT, NMIA, NIM, CMS/ITRI, KIM-LIPI, and KRISS) within the framework of the Asia-Pacific Metrology Programme (APMP) in order to determine their degrees of equivalence in the pressure range from 50 MPa to 500 MPa in gauge mode. The pilot institute was the National Metrology Institute of Japan (NMIJ/AIST). All participating institutes used hydraulic pressure balances as their pressure standards. A set of pressure balance with a free-deformational piston-cylinder assembly was used as the transfer standard. Three piston-cylinder assemblies, only one at a time, were used to complete the measurements in the period from November 2010 to January 2013. Ten participants completed their measurements and reported the pressure-dependent effective areas of the transfer standard at specified pressures with the associated uncertainties. Since one of the participants withdrew its results, the measurement results of the nine participants were finally compared. The results were linked to the CCM.P-K13 reference values through the results of two linking laboratories, NMIJ/AIST and NPLI. The degrees of equivalence were evaluated by the relative deviations of the participants' results from the CCM.P-K13 key comparison reference values, and their associated combined expanded (k=2) uncertainties. The results of all the nine participating NMIs agree with the CCM.P-K13 reference values within their expanded (k=2) uncertainties in the entire pressure range from 50 MPa to 500 MPa. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  7. Relationship of cerebrospinal fluid pressure, fungal burden and outcome in patients with cryptococcal meningitis undergoing serial lumbar punctures.

    NARCIS (Netherlands)

    Bicanic, T.; Brouwer, A.E.; Meintjes, G.; Rebe, K.; Limmathurotsakul, D.; Chierakul, W.; Teparrakkul, P.; Loyse, A.; White, N.J.; Wood, R.; Jaffar, S.; Harrison, T.

    2009-01-01

    OBJECTIVES: To assess impact of serial lumbar punctures on association between cerebrospinal fluid (CSF) opening pressure and prognosis in HIV-associated cryptococcal meningitis; to explore time course and relationship of opening pressure with neurological findings, CSF fungal burden, immune respons

  8. 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.

  9. Numerical prediction of pressure loss of fluid in a T-junction

    Directory of Open Access Journals (Sweden)

    Mohammed Abdulwahhab, Niranjan Kumar Injeti, Sadoun Fahad Dakhi

    2013-01-01

    Full Text Available This work presents a prediction of pressure loss of fluid with turbulent incompressible flow through a 90° tee junction was carried out and compared with analytical and experimental results. One turbulence model was used in the numerical simulations: k-ε model for two different values of area ratio between the main pipe and the branch pipe were 1.0 and 4.0, and flow rate ratios. The continuity, momentum and energy equations were discredited by means of a finite volume technique and the SIMPLE algorithm scheme was applied to link the pressure and velocity fields inside the domain. A three dimensional steady state flow was solving by using CFX 5 code ANSYS FLUENT13. The effect of the flow rate ratio q (ratio between the flow rate in the branch and outlet pipes on pressure drop and velocity profile was predicted at different Reynolds numbers. The results show that increasing the flow rate ratio the pressure and total energy losses increase because the presence of recirculation and the strong streamline curvature.

  10. Numerical prediction of pressure loss of fluid in a T-junction

    Energy Technology Data Exchange (ETDEWEB)

    Abdulwahhab, Mohammed; Kumar Injeti, Niranjan [Department of Marin Engineering, Andhra University, AP (India); Fahad Dakhil, Sadoun [Department of Fuel and Energy, Basrah Technical College (Iraq)

    2013-07-01

    This work presents a prediction of pressure loss of fluid with turbulent incompressible flow through a 90° tee junction was carried out and compared with analytical and experimental results. One turbulence model was used in the numerical simulations: {kappa}-{epsilon} model for two different values of area ratio between the main pipe and the branch pipe were 1.0 and 4.0, and flow rate ratios. The continuity, momentum and energy equations were discredited by means of a finite volume technique and the SIMPLE algorithm scheme was applied to link the pressure and velocity fields inside the domain. A three dimensional steady state flow was solving by using CFX 5 code ANSYS FLUENT13. The effect of the flow rate ratio q (ratio between the flow rate in the branch and outlet pipes) on pressure drop and velocity profile was predicted at different Reynolds numbers. The results show that increasing the flow rate ratio the pressure and total energy losses increase because the presence of recirculation and the strong streamline curvature.

  11. Experimental Studies of Dynamic Fault Weakening Due to Thermal Pressurization of Pore Fluids

    Science.gov (United States)

    Goldsby, David; Tullis, Terry; Platt, John; Okazaki, Keishi

    2016-04-01

    High-velocity friction experiments and geophysical observations suggest that mature faults weaken dramatically during seismic slip. However, while many coseismic weakening mechanisms have been proposed, it is still unclear which mechanisms are most important or how the efficiency of weakening varies within the seismogenic zone. Thermal pressurization is one possible coseismic weakening mechanism driven by the thermal expansion of native pore fluids, which leads to elevated pore pressures and significant coseismic weakening. While thermal pressurization has been studied theoretically for many decades, and invoked in recent earthquake simulations, its activation in laboratory experiments has remained elusive. Several high-speed friction studies have yielded indirect evidence for thermal pressurization, yet none has directly linked with existing theoretical models or the relevant physical parameters, such as permeability, slip, and slip rate, that control the weakening rate. To fill this gap, we are conducting thermal pressurization experiments on fluid-saturated, low-permeability rocks (Frederick diabase) at slip rates up to ~5 mm/s, at constant confining pressures in the range 21-149 MPa and initial imposed pore pressures in the range 10-25 MPa. The impractically low permeability of the as-is diabase, ~10-23 m2, is increased prior to the test by thermal cracking, yielding measured permeabilities in the range 1.3*10-18 to 6.1*10-19 m2. These values of permeability are high enough to allow sample saturation over one to several days, but low enough to confine the elevated pore pressures generated by frictional heating during rapid sliding. Our experiments reveal a rapid decay of shear stress following a step-change in velocity from 10 μm/s to 4.8 mm/s. In one test, the decrease in shear stress of ~25% over the first 28 mm of slip at 4.8 mm/s agrees closely with the theoretical solution for slip on a plane (Rice [2006]), with an inferred slip-weakening distance of ~500

  12. Practical development of continuous supercritical fluid process using high pressure and high temperature micromixer

    Science.gov (United States)

    Kawasaki, Shin-Ichiro; Sue, Kiwamu; Ookawara, Ryuto; Wakashima, Yuichiro; Suzuki, Akira

    2015-12-01

    In the synthesis of metal oxide fine particles by continuous supercritical hydrothermal method, the particle characteristics are greatly affected by not only the reaction conditions (temperature, pressure, residence time, concentration, etc.), but also the heating rate from ambient to reaction temperature. Therefore, the heating method by direct mixing of starting solution at room temperature with supercritical water is a key technology for the particle production having smaller size and narrow distribution. In this paper, mixing engineering study through comparison between conventional T-shaped mixers and recently developed swirl mixers was carried out in the hydrothermal synthesis of NiO nanoparticles from Ni(NO3)2 aqueous solution at 400 °C and 30 MPa. Inner diameter in the mixers and total flow rates were varied. Furthermore, the heating rate was calculated by computational fluid dynamics (CFD) simulation. Relationship between the heating rate and the average particle size were discussed. It was clarified that the miniaturization of mixer inner diameter and the use of the swirl flow were effective for improving mixing performance and contributed to produce small and narrow distribution particle under same experimental condition of flow rate, temperature, pressure, residence time, and concentration of the starting materials. We have focused the mixer optimization due to a difference in fluid viscosity.

  13. A Validated All-Pressure Fluid Drop Model and Lewis Number Effects for a Binary Mixture

    Science.gov (United States)

    Harstad, K.; Bellan, J.

    1999-01-01

    The differences between subcritical liquid drop and supercritical fluid drop behavior are discussed. Under subcritical, evaporative high emission rate conditions, a film layer is present in the inner part of the drop surface which contributes to the unique determination of the boundary conditions; it is this film layer which contributes to the solution's convective-diffusive character. In contrast, under supercritical condition as the boundary conditions contain a degree of arbitrariness due to the absence of a surface, and the solution has then a purely diffusive character. Results from simulations of a free fluid drop under no-gravity conditions are compared to microgravity experimental data from suspended, large drop experiments at high, low and intermediary temperatures and in a range of pressures encompassing the sub-and supercritical regime. Despite the difference between the conditions of the simulations and experiments (suspension vs. free floating), the time rate of variation of the drop diameter square is remarkably well predicted in the linear curve regime. The drop diameter is determined in the simulations from the location of the maximum density gradient, and agrees well with the data. It is also shown that the classical calculation of the Lewis number gives qualitatively erroneous results at supercritical conditions, but that an effective Lewis number previously defined gives qualitatively correct estimates of the length scales for heat and mass transfer at all pressures.

  14. Impact of Initial Central Venous Pressure on Outcomes of Conservative versus Liberal Fluid Management in Acute Respiratory Distress Syndrome

    Science.gov (United States)

    Semler, Matthew W.; Wheeler, Arthur P.; Thompson, B. Taylor; Bernard, Gordon R.; Wiedemann, Herbert P.; Rice, Todd W.

    2016-01-01

    Objective In acute respiratory distress syndrome (ARDS), conservative fluid management increases ventilator-free days without affecting mortality. Response to fluid management may differ based on patients’ initial central venous pressure (CVP). We hypothesized initial CVP would modify the effect of fluid management on outcomes. Design Retrospective analysis of the Fluid and Catheter Treatment Trial, a multicenter randomized trial comparing conservative to liberal fluid management in ARDS. We examined the relationship between initial CVP, fluid strategy, and 60-day mortality in univariate and multivariable analysis. Setting Twenty acute care hospitals. Patients Nine hundred and thirty-four ventilated ARDS patients with a CVP available at enrollment, 609 without baseline shock (for whom fluid balance was managed by study protocol). Interventions None. Measurements and Main Results Among patients without baseline shock, those with initial CVP > 8 mmHg experienced similar mortality with conservative and liberal fluid management (18% versus 18%, p=0.928), whereas those with CVP ≤8 mmHg experienced lower mortality with a conservative strategy (17% versus 36%, p=0.005). Multivariable analysis demonstrated an interaction between initial CVP and the effect of fluid strategy on mortality (p=0.031). At higher initial CVPs, the difference in treatment between arms was predominantly furosemide administration, which was not associated with mortality (p=0.122). At lower initial CVPs, the difference between arms was predominantly fluid administration, with additional fluid associated with increased mortality (p=0.013). Conclusions Conservative fluid management decreases mortality fo