WorldWideScience

Sample records for plain horizontal tubes

  1. A comprehensive study of modified Wilson plot technique to determine the heat transfer coefficient during condensation of steam and R-134a over single horizontal plain and finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ravi; Varma, H.K.; Agrawal, K.N.; Mohanty, Bikash

    2001-03-01

    In the present investigation a comprehensive study of the modified Wilson plot technique has been made and a stepwise methodology has been evolved. This technique can be used to determine the condensing-side heat transfer coefficient during condensation of vapor over a horizontal tube. The necessary experimental data have been acquired by conducting experiments for the condensation of steam and R-134a over a plain tube and different finned tubes (CIFTs and SIFTs). The experimental heat transfer coefficient, based on the test-section wall temperature measurement (wall temperature was measured with thermocouples), h{sub o}, has been compared with that predicted by the modified Wilson plot technique, h{sub mw}. The modified Wilson plot technique underpredicted the condensing-side heat transfer coefficient for the condensation of steam in a range of 7.5-15%. The heat transfer coefficient for the condensation of R-134a is also underpredicted in a range of 13-25% by this technique. (Author)

  2. Film condensation of steam on externally finned horizontal tubes.

    OpenAIRE

    Flook, Frederick A.

    1985-01-01

    Approved for public release; distribution is unlimited Filmwise condensation measurements of steam were made on horizontal finned tubes under vacuum and near-atmospheric conditions. Data were obtained for copper tubes with fins of rectangular, triangular, trapezoidal, and parabolic cross sections, and for a commercially-available finned tube. A stainless steel finned tube was also tested to investigate the effect of thermal conductivity. Maximum enhancements of about 4.8 were obtained...

  3. High-quality Critical Heat Flux in Horizontally Coiled Tubes

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    An investigation on the high-quality dryout in two electrically heated coiled tubes with horizontally helix axes is reported.The temperature profiles both along the tube and around the circumference are measured.and it is found that the temperature profiles around the circumference are not identical for the corss-sections at different parts of the coil.The “local condition hypothesis” seems applicable under present conditions,and the critical heat flux qcr decreases with increasing critical quality xcr.The CHF increases as mass velocity and ratio of tube diameter to coil diameter(d/D) increases,and it seems not to be affected hby the system pressure.The CHF is larger with coils than that with straight tubes,and the difference increases with increasing mass velocity and d/D.

  4. A COMPARISON OF HEAT TRANSFER AROUND A SINGLE SERRATED FINNED TUBE AND A PLAIN FINNED TUBE

    Directory of Open Access Journals (Sweden)

    S.R.Mcilwain

    2010-02-01

    Full Text Available With comparable bundle geometry, serrated fin finned tube heat exchangers transfer more heat than plain finned ones. There are believed to be many factors in this behaviour, and this investigation used CFD to examine the heat transfer and fluid flow patterns around the fins to try to understand the magnitude of the differences in the processes. The study is a first step in developing a new theory-based method to predict the performance of serrated fin tube bundles.

  5. A COMPARISON OF HEAT TRANSFER AROUND A SINGLE SERRATED FINNED TUBE AND A PLAIN FINNED TUBE

    OpenAIRE

    2010-01-01

    With comparable bundle geometry, serrated fin finned tube heat exchangers transfer more heat than plain finned ones. There are believed to be many factors in this behaviour, and this investigation used CFD to examine the heat transfer and fluid flow patterns around the fins to try to understand the magnitude of the differences in the processes. The study is a first step in developing a new theory-based method to predict the performance of serrated fin tube bundles.

  6. Convective condensation heat transfer in a horizontal condenser tube

    Energy Technology Data Exchange (ETDEWEB)

    Sarma, P.K. [College of Engineering, GITAM, Visakhapatnam (India); Sastry, C.V.N.; Rao, V.D. [Andhra Univ., College of Engineering, Visakhapatnam (India); Kakac, S.; Liu, H. [Miami Univ., College of Engineering, FL (United States)

    2002-03-01

    The purpose of this article is to solve analytically the problem of convective condensation of vapors inside a horizontal condenser tube. Homogeneous model approach is employed in the estimation of shear velocity, which is subsequently, made use of in predicting local convective condensation heat transfer coefficients. The resulting analysis of the present study is compared with some of the available equations in the literature. It is observed that the agreement is reasonably satisfactory validating the assumptions and the theory presented. (authors)

  7. Condensation of Refrigerant-11 on the outside of horizontal and inclined enhanced tubes

    Energy Technology Data Exchange (ETDEWEB)

    Domingo, N.

    1982-12-01

    Heat transfer condensation tests with Refrigerant-11 were performed on the outside of a smooth tube and a variety of enhanced tubes oriented horizontally and at various tube inclinations. One smooth tube and seven enhanced (externally fluted, roped, spiraled, and externally finned) tubes of 2.54-cm (1-in.) nominal outside diameter and 1.17-m (4-ft) length were tested. Several of the tested tubes featured internal enhanced geometries, which were caused by the heat transfer enhancing geometry on the tube's external surface. Condensing heat transfer coefficients are reported as composite coefficients, which combine the resistance of the condensing film and the tube wall, and are based on total tube outside surface area. Results show that in the horizontal condensing mode, the rank order (best to worst) of the tube geometries tested was spiral-shaped tubes, rope-shaped tubes, smooth tube, externally finned tube, and externally fluted tube. For a spiral-shaped tube, horizontal composite coefficients were up to 2.0 times the corresponding horizontal smooth tube values. For tilt angles greater than or equal to 60/sup 0/ from the horizontal, the condensing performance of the externally fluted tube was best of all the tubes tested.

  8. Condensation heat transfer of steam on a single horizontal tube

    Science.gov (United States)

    Graber, K. A.

    1983-06-01

    An experimental apparatus was designed, constructed and instrumented in an effort to systematically and carefully study the condensation heat-transfer coefficient on a single, horizontal tube. A smooth, thick-walled copper tube of length 133.5 mm, with an outside diameter of 15.9 mm and an inside diameter of 12.7 mm was instrumented with six wall thermocouples. The temperature rise across the test section was measured accurately using quartz crystal thermometers. The inside heat-transfer coefficient was determined using the Sieder-Tate correlation with leading coefficient of 0.029. Initial steam side data were taken at atmospheric pressure to test the data acquisition/reduction computer programs.

  9. Performance study on primary gas coolers with horizontal tubes

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, E.L.; Lekhter, V.I.; Gostev, Yu.A. [and others

    1992-12-31

    No. 1-bis coke-oven battery system at the Mariupol C&CW was equipped with primary gas coolers of horizontal-tube type. They consisted of three sections, with working surface areas in m{sup 2} of: I (bottom) 800 (middle) 800 and III (top) 600 respectively. The nominal water flow rate through each cooler was 600-720 m. The coolers were constantly irrigated with tar/water emulsions to remove scale deposits in the inter-tube space. The circulating water from the primary gas coolers is cooled in a e-section cooling tower (type 2VG) equipped with spray nozzles designed by the Dnepropetrovsk Chemical Technology Institute (nominal water throughput 3000 m{sup 3}/h). 1 tab.

  10. Velocity Profiles between Two Baffles in a Horizontal Circular Tube

    Institute of Scientific and Technical Information of China (English)

    Tae-Hyun Chang; Hae-Soo Lee; Keon-Je Oh; Doeg Hee Doh; Chang-Hoan Lee

    2014-01-01

    The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted heat.The baffles are also an important element inside the heat exchanger.Internal materials influence the flow pattern in the bed.The influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular tube.The velocity of the particles was measured before the baffle and between them in the test tube.Results show that the flows near the front baffle flow were parallel to the vertical wall,and then concentrate on the upper opening of the front baffle.The flows circulate in the front and rear baffles.These flow profiles are related to the Reynolds number (Re) or the flow intensity.The velocity profiles at lower Re number showed a complicated mixing,concentrating on the lower opening of the rear baffle as front wall.Swirling flow was employed in this study,which was produced using tangential velocities at the inlet.At the entrance of the front baffle,the velocity vector profiles with swirl were much different from that without swirl.However,velocities between two baffles are not much different from those without swirl.

  11. Velocity profiles between two baffles in a horizontal circular tube

    Science.gov (United States)

    Chang, Tae-Hyun; Lee, Hae-Soo; Oh, Keon-Je; Doh, Doeg Hee; Lee, Chang-Hoan

    2014-12-01

    The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted heat. The baffles are also an important element inside the heat exchanger. Internal materials influence the flow pattern in the bed. The influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular tube. The velocity of the particles was measured before the baffle and between them in the test tube. Results show that the flows near the front baffle flow were parallel to the vertical wall, and then concentrate on the upper opening of the front baffle. The flows circulate in the front and rear baffles. These flow profiles are related to the Reynolds number (Re) or the flow intensity. The velocity profiles at lower Re number showed a complicated mixing, concentrating on the lower opening of the rear baffle as front wall. Swirling flow was employed in this study, which was produced using tangential velocities at the inlet. At the entrance of the front baffle, the velocity vector profiles with swirl were much different from that without swirl. However, velocities between two baffles are not much different from those without swirl.

  12. Selection of plain or segmented finned tubes for heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Reid, D.R.; Taborek, Jerry (Fintube Corp. (United States))

    1994-01-01

    Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded ''plain'' fins were generally used in the past - until the high-frequency resistance welding technology permitted the cost-effective manufacture of segmented fins. The main advantage of the segmented fin design is that it permits higher heat flux and hence smaller, lighter units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight and cost per unit area, favour the segmented fin design, a few other considerations, such as fouling, ease of cleaning and availability of dependable design methods, have to be considered. This article analyses the performance parameters that affect the selection of either fin type. (4 figures, 1 table, 10 references) (Author)

  13. Experimental investigation of ice slurry heat transfer in horizontal tube

    Energy Technology Data Exchange (ETDEWEB)

    Grozdek, Marino; Khodabandeh, Rahmatollah; Lundqvist, Per; Palm, Bjoern; Melinder, Aake [Department of Energy Technology, Division of Applied Thermodynamics and Refrigeration, Royal Institute of Technology, Brinellvaegen 68, 10044 Stockholm (Sweden)

    2009-09-15

    Heat transfer of ice slurry flow based on ethanol-water mixture in a circular horizontal tube has been experimentally investigated. The secondary fluid was prepared by mixing ethanol and water to obtain initial alcohol concentration of 10.3% (initial freezing temperature -4.4 C). The heat transfer tests were conducted to cover laminar and slightly turbulent flow with ice mass fraction varying from 0% to 22% depending on test performed. Measured heat transfer coefficients of ice slurry are found to be higher than those for single phase fluid, especially for laminar flow conditions and high ice mass fractions where the heat transfer is increased with a factor 2 in comparison to the single phase flow. In addition, experimentally determined heat transfer coefficients of ice slurry flow were compared to the analytical results, based on the correlation by Sieder and Tate for laminar single phase regime, by Dittus-Boelter for turbulent single phase regime and empirical correlation by Christensen and Kauffeld derived for laminar/turbulent ice slurry flow in circular horizontal tubes. It was found that the classical correlation proposed by Sieder and Tate for laminar forced convection in smooth straight circular ducts cannot be used for heat transfer prediction of ice slurry flow since it strongly underestimates measured values, while, for the turbulent flow regime the simple Dittus-Boelter relation predicts the heat transfer coefficient of ice slurry flow with high accuracy but only up to an ice mass fraction of 10% and Re{sub cf} > 2300 regardless of imposed heat flux. For higher ice mass fractions and regardless of the flow regime, the correlation proposed by Christensen and Kauffeld gives good agreement with experimental results. (author)

  14. Particle seeding flow system for horizontal shock tube

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Stephen [Los Alamos National Laboratory; Garcia, Nicolas J. [Los Alamos National Laboratory; Martinez, Adam A. [Los Alamos National Laboratory; Orlicz, Gregory C. [Los Alamos National Laboratory; Prestridge, Katherine P. [Los Alamos National Laboratory

    2012-08-01

    The Extreme Fluids Team in P-23, Physics Division, studies fluid dynamics at high speeds using high resolution diagnostics. The unsteady forces on a particle driven by a shock wave are not well understood, and they are difficult to model. A horizontal shock tube (HST) is being modified to collect data about the behavior of particles accelerated by shocks. The HST has been used previously for studies of Richtmyer-Meshkov instability using Planar Laser-Induced Fluorescence (PLIF) as well as Particle Image Velocimetry (PIV), diagnostics that measure density and velocity. The purpose of our project is to design a flow system that will introduce particles into the HST. The requirements for this particle flow system (PFS) are that it be non-intrusive, be able to introduce either solid or liquid particles, have an exhaust capability, not interfere with existing diagnostics, and couple with the existing HST components. In addition, the particles must flow through the tube in a uniform way. We met these design criteria by first drawing the existing shock tube and diagnostics and doing an initial design of the ducts for the PFS. We then estimated the losses through the particle flow system from friction and researched possible fans that could be used to drive the particles. Finally, the most challenging component of the design was the coupling to the HST. If we used large inlets, the shock would lose strength as it passed by the inlet, so we designed a novel coupling inlet and outlet that minimize the losses to the shock wave. Our design was reviewed by the Extreme Fluids Team, and it is now being manufactured and built based upon our technical drawings.

  15. Enhancement of heat transfer in condensation of refrigerant vapor on horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, O.P.; Khizhnyakov, S.V. (Northwestern Polytechnic Inst. (SU))

    1991-01-01

    This paper reports on the technique for predicting the heat transfer coefficients in film condensation of Freons on horizontal tubes with different fin geometries that has been improved. The suggested technique allows for the spatial orientation of the different parts of the heat transfer area, the capillary contraction of condensate, and its holdup on the bottom zone of the horizontal tube.

  16. Evaporation of refrigerant HFC 407C on plain tubes or at an improved surface; Evaporation du refrigerant HFC 407C sur des tubes lisses ou a surface amelioree

    Energy Technology Data Exchange (ETDEWEB)

    Zuercher, O.; Favrat, D.; Thome, J.R.; Kattan, N.; Nidegger, E. [Ecole polytechnique federale, Lab. d`energetique industrielle, Lausanne (Switzerland)

    1996-11-15

    The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requires good methods for predicting heat transfer of substitute fluids. The measurements in the LENI test facility (concentric tubes with water flowing in a counter-current flow) with HFC 407C, HFC 134a, HCFC 123, HFC 404a and HFC/HCFC 402A provide a new data bank for new refrigerants, and allow a coherent comparison with old refrigerants CFC 11, CFC 12, CFC/HCFC 502 and with existing correlations. The existing correlations were found to be inadequate. Because of this work, an improved flow pattern map and flow boiling model were developed, which resulted in a substantial progress in the accurate predict of heat transfer in plain, horizontal tubes for refrigerants without oil. The Kattan et al. correlation was programmed to calculate and compare predicted heat transfer coefficients to the new HFC 407C test data. The flow pattern map proposed by Kattan et al. was also programmed and compared to flow regimes observed for HFC 407C. It predicted the HFC 407C flow pattern data quite accurately. The original objective of the HFC 407C measurements was the validation of the Kattan et al. correlation applied to a zeotropic refrigerant blend. Local flow boiling heat transfer coefficients were measured for HFC 407C evaporating inside a microfin and a plain tube. In addition, microfin heat transfer augmentation relative to a plain tube was investigated. The presence of oil in the evaporator had a complex effect on heat transfer coefficients. Local flow boiling heat transfer coefficients were measured for refrigerant HFC 407C ester oil mixtures (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of zeotropic refrigerant blends and lubricating oils was also developed. (author) figs., tabs., 14 refs.

  17. Effect of vapor velocity during condensation on horizontal finned tubes

    OpenAIRE

    Hopkins, Charles Louis III

    1988-01-01

    Approved for public release; distribution is unlimited Heat-transfer measurements were made for condensation of R-113 and steam on a smooth tube and on three finned tubes with rectangular shape fins. These tubes had a fin height and width of 1.0 mm and spacings of 0.25, 1.5, and 4.0 mm (tubes A, B, and C respectively) . Data were taken by increasing the vapor velocity from 0.4 to 1.9 m/s for R-113 and 4.8 to 31.3 m/s for steam. For both fluids, the improvement of the c...

  18. Heat transfer in a membrane assisted fluidized bed with immersed horizontal tubes

    NARCIS (Netherlands)

    Deshmukh, Salim A.R.K.; Volkers, Sander; Sint Annaland, van Martin; Kuipers, Hans

    2005-01-01

    The effect of gas permeation through horizontally immersed membrane tubes on the heat transfer characteristics in a membrane assisted fluidized bed operated in the bubbling fluidization regime was investigated experimentally. Local time-averaged heat transfer coefficients from copper tubes arranged

  19. Heat transfer in a membrane assisted fluidised bed with immersed horizontal tubes

    NARCIS (Netherlands)

    Deshmukh, S.A.R.K.; Volkers, S.; Sint Annaland, van M.; Kuipers, J.A.M.

    2004-01-01

    The effect of gas permeation through horizontally immersed membrane tubes on the heat transfer characteristics in a membrane assisted fluidised bed was investigated experimentally. Local time-averaged heat transfer coefficients from copper tubes arranged in a staggered formation with the membrane tu

  20. EXPERIMENTAL STUDY OF CONDENSATION HEAT TRANSFER CHARACTERISTICS OF HORIZONTAL TUBE BUNDLES IN VACUUM STATES

    Institute of Scientific and Technical Information of China (English)

    CHENG Shen; SUN Feng-zhong; SHI Yue-tao

    2012-01-01

    To develop an excellent heat transfer element under the vacuum condition,experiments about the heat transfer performance of horizontal tube bundles of different materials under various vacuum conditions were carried out,including the stainless steel tube,the brass tube,the Ni-based implanted steel tube and the ion implanted brass tube.The relative trends show that the condensation heat transfer coefficient and the overall heat transfer coefficient of bundles of four materials all increase with the vacuum degree,especially,those of the Ni-based implanted steel tube and the ion implanted brass tube.Under a high vacuum condition (0.07 MPa),the condensation heat transfer coefficient of the Ni-based implanted steel tube bundle is about 1.4 times of that of the stainless steel tube bundle,the condensation heat transfer coefficient of the ion implanted brass tube bundle is found to be about 1.3 times of that of the common brass tube bundle.Therefore,according to the condensation heat transfer characteristics studied under high vacuum conditions,it is believed that a dropwise condensation is partly achieved on the surface of these two implanted tube bundles,and the ion implantation is shown to be an effective method to achieve the dropwise condensation.Based on this study,it is believed that the Ni-based steel tube may replace the brass tube,which is more expensive as a heat transfer component.

  1. Condensation inside tubes: Computer program for pressure drop in straight tubes (horizontal and vertical with downflow)

    Science.gov (United States)

    1993-12-01

    ESDU 93014 introduces a Fortran program that implements the calculation procedures of ESDU 90024 and 91023 respectively for vertical and horizontal cases. Those documents should be consulted for details of the empirical correlation used. Since vapor density is an important variable in the calculation and is usually available as a function of saturation temperature, the relationship between pressure and saturation temperature is required at points along the tube, although a constant value of vapor density may be used if the user wishes. The program provides options to use an Antoine or Wagner equation, or to provide a set of values of saturation pressure and temperature; for the vapor density the options are to use the ideal gas law, to provide a set of values of saturation temperature and density or to use a specific correlation equation (log density as a fraction of critical as a five term polynomial function of reciprocal reduced temperature minus one). For a wide range of pure compounds the ESDU Physical Data, Chemical Engineering Sub-series provides values of the constants in the correlation equations for saturation temperature and vapor density. The program (ESDUpac A9314) is provided on disc (uncompiled) in the software volume, and also compiled within ESDUview, a user-friendly shell running under MS DOS that prompts on screen for the input data. A worked example illustrates the use of the program and the formats of the input data and the output.

  2. Burnout in the horizontal tubes of a furnace waterwall panel

    Energy Technology Data Exchange (ETDEWEB)

    B.Y. Kamenetskii [All-Russia Research Institute of Nuclear Power Engineering (OAO VNIIAM), Moscow (Russian Federation)

    2009-07-01

    An experimental study of heat transfer that occurs in tubes nonuniformly heated over the perimeter at low velocities of subcooled water flowing in them is presented. Experiments with unsteady supply of heat made it possible to determine heat fluxes under burnout conditions. Unusually low values of critical heat fluxes were obtained under such conditions.

  3. Burnout in the horizontal tubes of a furnace waterwall panel

    Science.gov (United States)

    Kamenetskii, B. Ya.

    2009-08-01

    An experimental study of heat transfer that occurs in tubes nonuniformly heated over the perimeter at low velocities of subcooled water flowing in them is presented. Experiments with unsteady supply of heat made it possible to determine heat fluxes under burnout conditions. Unusually low values of critical heat fluxes were obtained under such conditions.

  4. Film condensation of R-113 on in-line bundles of horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H. (Kyushu Univ., Fukuoka (Japan)); Uchima, B.; Nozu, S.; Nakata, H.; Torigoe, E. (Okayama Univ. (Japan))

    1991-05-01

    Film condensation of R-113 on in-line bundles of horizontal finned tubes with vertical vapor downflow was experimentally investigated. Two tubes with flat-sided annular fins and four tubes with three-dimensional fins were tested. The test sections were 3 {times} 15 tube bundles with and without two rows of inundation tubes at the top. Heat transfer measurements were carried out on a row-by-row basis. The heat transfer enhancement due to vapor shear was much less for a finned tube bundle than for a smooth tube bundle. The decrease in heat transfer due to condensate inundation was more marked for a three-dimensional fin tube than for a flat-sided fin tube. The predictions of the previous theoretical model for a bundle of flat-sided fin tubes agreed well with the measured data for low vapor velocity and a small to medium condensate inundation rate. Among the six tubes tested, the highest heat transfer performance was provided by the flat-sided fin tube with fin dimensions close to the theoretically determined optimum values.

  5. Forced Convective Condensation of Nonazeotropic Refrigerant Mixtures in Horizontal Annulus with Petal Shaped Fin Tubes

    Institute of Scientific and Technical Information of China (English)

    WangShiping; ZhouXinqiu; 等

    1995-01-01

    In this paper,condensation performance in horizontal annulus was compared with a smooth tube,one Saw-Tooth Finned tube(STF tube),four Petal Shaped Fin tubes(PF tubes),using R113,R11 and their mixtures(vapor molar fractions of R11 at the test section inlet were 0.384,0.588and 0.809) as working fluid.The mass flux at the test section ranged from 15-220/m2s。Camera and video camera were used to shoot the flow pattern and condensation phenomena.The condensation transfer coefficient(hc) of mixtures were considerably lower than those of pure fluid,and did not change linearly with composition.The maximum degradation of measured hc from the ideal value were 23% for the smooth tube,65%for STF tube,67% for PF tubes,which occurred in the composition range of 0.4-0.6 vapor molar fraction of R11.For the condensation of mixture,R11 molar fraction from 38%to 81%,the PF tubes had the highest value of hc.which were 10-25% higher than those of STF tubes,and 480-580% higher than that of smooth tube,because the petal shaped fins of PF tubes could promote strong turbulence in the two phase flow,and reduce the mass transfer resistance.

  6. Effect of Vapor Velocity during Condensation on Horizontal Finned Tubes

    Science.gov (United States)

    1988-12-01

    surface area (m2 ) b Fin spacing (mm) Ci Sieder -Tate type coefficient used in Equation (4.5) C p Specific heat of cooling water (J/kgK) Di Inside diameter...and auxiliary condensers, together with the energy lost to the environment. Raw data were processed immediately using an assumed value for the Sieder ...sets were collected, the data were reprocessed using a new Sieder -Tate coefficient found by the modified Wilson method. 40 F. TUBES TESTED For this

  7. Film Condensation of Steam on Externally Finned Horizontal Tubes.

    Science.gov (United States)

    1985-03-01

    Area Based on the Fin Diameter b - Experimentally Determined Constant B - Constant Used in the Sieder -Tate-Type Equation c - Experimentally Determined...Constant C - Leading Coefficient for the Sieder -Tate-Type Equation C1 - Constant of Proportionality d - Experimentally Determined Constant De...leading constants for the Sieder -Tate equation used to determine the water-side heat-transfer coefficient. Data taken on smooth tubes were used to

  8. Film Condensation of Steam on Externally Enhanced Horizontal Tubes.

    Science.gov (United States)

    1986-03-01

    all the runs were collected, the data were reprocessed using a new Sieder -Tate Coefficient found by the modified Wilson method. E. TUBES TESTED For... Sieder -Tate constant 16 for the inside heat-transfer coefficient. The separation of the individual thermal resistances (water-side, wall, and vapor...overall heat-transfer resistance is given by equation (4.1), while the inside heat-transfer coefficient is given by a Sieder -Tate type equation (equation

  9. Investigating the Nanoparticles Penetration Efficiency through Horizontal Tubes Using an Experimental Approach

    Directory of Open Access Journals (Sweden)

    Zhaoqin Yin

    2015-01-01

    Full Text Available It is a complex transfer process of nanoparticles in a tube. In this paper, in order to quantify the penetration efficiency of nanoparticles in different flows condition through horizontal tubes, the experiments have been carried out with particles diameter between 6 nm and 560 nm in various lengths of sampling tube. The results were in good agreement with the theory of Gormley and Kennedy and the experiment results of Kumar et al. for particles size smaller than 100 nm. Particles penetration rate increases with increasing of the Schmidt number (Sc, and it decreases with increasing Reynolds and tube length. Particles deposition on the wall induces the changes of the mass and average diameter of particles continuously. Therefore, a nondimensional parameter (ς defined dependency on Reynolds number and particle residence time in tube has been used to express total mass penetration efficiency and mean size growth rate through a straight tube.

  10. Film condensation of R-113 on staggered bundles of horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H. (Kyushu Univ., Fukuoka (Japan)); Uchima, B. (Kagawa Technical Coll., Marugame (Japan)); Nozu, S.; Torigoe, E.; Imai, S. (Okayama Univ., Tsushima (Japan))

    1992-05-01

    Film condensation of R-113 on staggered bundles of horizontal finned tubes with vertical vapor downflow was experimentally investigated. Two tubes with flat-sided annular fins and four tubes with three-dimensional fins were tested. The condensate flow and heat transfer characteristics were compared with the previous results for in-line bundles of the same test tubes and a staggered bundle of smooth tubes. The decrease in heat transfer characteristics were compared with the previous results for in-line bundles of the same test tubes and a staggered bundle of smooth tubes. The decrease in heat transfer due to condensate inundation was most significant for the in-line bundles of the three-dimensional fin tubes, whereas the decrease was very slow for both the staggered and in-line bundles of the flat-sided fin tubes. The predictions of the previous theoretical model for a bundle of flat-sided fin tubes agreed fairly well with the measured data at a low vapor velocity. The highest heat transfer performance was provided by the staggered bundle of flat-sided fin tubes with fin dimensions close to the theoretically determined optimum values.

  11. A theoretical model of film condensation in a bundle of horizontal low finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Nozu, S.; Takeda, Y. (Okayama Univ. (Japan))

    1989-05-01

    The previous theoretical model of film condensation on a single horizontal low finned tube is extended to include the effect of condensate inundation. Based on the flow characteristics of condensate on a vertical column of horizontal low finned tubes, two major flow modes, the column mode and the sheet mode, are considered. In the column mode, the surface of the lower tubes is divided into the portion under the condensate column where the condensate flow is affected by the impinging condensate from the upper tubes, and the portion between the condensate columns where the condensate flow is not affected by the impinging condensate. In the sheet mode, the whole tube surface is assumed to be affected by the impinging condensate. Sample calculations for practical conditions show that the effects of the fin spacing and the number of vertical tube rows on the heat transfer performance is significant for R-12, while the effects are small for steam. The predicted value of the heat transfer coefficient for each tube row compares well with available experimental data, including four fluids and five tube bundles.

  12. Further studies in filmwise condensation of steam on horizontal finned tubes

    OpenAIRE

    Swensen, Keith Andrew

    1992-01-01

    Approved for public release; distribution is unlimited Over the years, there has been significant variation in the filmwise steam condensation data at NOS on horizontal low0integral finned tubes. With a view to increasing the accuracy of the data, inserts were used inside the tubes to reduce inside thermal resistance; however, significant discrepancies then occurred in the calculated outside coefficient when compared to data taken without an insert. These discrepancies arose due to the d...

  13. Research on horizontal electromagnetic continuous casting of copper tube blanks

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The effect of commercial frequency electromagnetic field on the solidification structure and mechanical properties of copper hollow blanks prepared by horizontal continuous casting method was investigated. The results show that when the electromagnetic field is imposed, columnar grains are evidently refined and fine equiaxed grains are obtained in the inner side of the cross-section. Moreover, with the increase of input current, the equiaxed grain region widens and the grains distribute more uniformly in the circumferential direction. Meanwhile, the mechanical properties are remarkably improved by the application of electromagnetic field. When the input current is 140 A, the tensile strength increases 15% and the elongation increases 10%. However, the electromagnetic field has no effect on the distribution of microelements.

  14. Nucleate boiling at the forced flow of binary non-azeotropic mixtures in horizontal tubes

    Directory of Open Access Journals (Sweden)

    Mezentseva N.N.

    2015-01-01

    Full Text Available Analysis of experimental values of heat transfer coefficients obtained through investigation of nucleate boiling of the two-component non-azeotropic mixtures inside the horizontal smooth tubes by various authors is presented. In the zone of nucleate boiling, the experimental data are in good agreement with the calculation dependence.

  15. A Prediction Model for Condensation on Single Horizontal Rectangular Fin Tube

    Institute of Scientific and Technical Information of China (English)

    LiuXijuan; MaTongze; 等

    1997-01-01

    A model was established to predict condensation heat transfer coefficient on horizontal rectangularfinned tube.Drop-Off zone at the tube bottom was considered and determined,the known Honda (and Owen) expression of retention angle was also modified as a result of considering drop-off zone.Heat flux on fin tips in the unflooded region,fin flanks,fin spacings and fin tips in the flooded region were analyzed respectively.COndensation on fin tips in emphasized by considering the variation of film thickness along circumference as well as horizontally.FIn efficiency was considered in calculation.The prediction results were compared with several researchers' experimental data for three kinds of working fluids on seven different tube geometries and for various temperature differences,These data under about 60 test conditions were predicted with discrepancy of ±10% .Prediction by the present model for steam and R-113 condensation were compared with previous models.

  16. Convective Boiling of Near-Azeotropic Refrigerant R410A in the Horizontal Micro-fin Tube

    Institute of Scientific and Technical Information of China (English)

    DUAN Xue-tao; MA Hu-gen; WU Zhi-min; WANG Fang

    2007-01-01

    Using near-azeotropic refrigerant R410A as the working fluid, the experimental studies on the horizontal micro-fin tubes were conducted. Several factors affecting heat transfer coefficients were analyzed, and the characteristics of flow boiling of the refrigerant in the horizontal micro-fin tubes were discussed. The local heat transfer coefficients increase with mass flux, heat flux and quality. And the heat transfer enhancement factor of those testing tubes is about 1.6 to 2.2.

  17. Performance investigation of evaporatively-cooled heat exchangers - part one: plain and finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, A.; Siren, K.

    2004-07-01

    The performance of two evaporatively cooled heat exchangers is investigated under similar operating conditions of airflow rates and inlet hot water temperatures. The types of the heat exchangers are plain and plate-finned circular tube which occupy the same volume. A substantial increase in heat transfer takes place for the plate-finned tubes. The increase is 92-140% for air velocities from 1.66 to 3.57 m s{sup -1}. The wet-finned surfaces show low fin efficiency compared with dry surfaces. An energy index defined as the ratio of volumetric thermal conductance to air pressure drop per unit length is found to be close for the two heat exchangers. This reveals higher thermal utilisation of the occupied volume by the finned tubes with the same energy index. (orig.)

  18. CONDENSATION HEAT TRANSFER OF R-134A IN HORIZONTAL STRAIGHT AND HELICALLY COILED TUBE-IN-TUBE HEAT EXCHANGERS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This article presents an experimental investigation on condensation heat transfer of R-134a in horizontal straight and helically coiled tube-in-tube heat exchangers. The experiments were carried out at three saturation temperatures(35℃, 40℃ and 45℃) with the refrigerant mass flux varying from 100 kg/m2 s to 400 kg/m2 s and the vapor quality ranging from 0.1 to 0.8. The effects of vapor quality and mass flux of R-134a on the condensation heat transfer coefficient were investigated. The results indicate that the condensation heat transfer coefficients of the helical section are 4%-13.8% higher than that of the straight section. The experimental results were compared with the data available in literature for helical and straight pipes.

  19. Prediction of condensation heat transfer of low GWP refrigerants inside smooth horizontal tube

    Science.gov (United States)

    Hossain, Md. Anowar; Afroz, Hasan M. M.; Talukder, Shaon; Miyara, Akio

    2016-07-01

    The present research work observed the experimental and analytical results of two phase condensation heat transfer of the refrigerants R1234ze(E), R32, R410A, and R1234ze(E)/R32 mixtures inside a smooth horizontal tube. A water heated double tube horizontal heat exchanger with effective length of 3.6m and inner diameter of 4.35mm is used to take place the experiment. Mass flux and the saturation temperature are the design variables under which the experiment is carried out whose values varying from the range 160 to 400 Kg m-2s-1 and 30°C to 45°C, respectively. A new correlation for pure refrigerant has been proposed to predict the heat transfer inside a smooth horizontal tube by investigating the experimental data. The newly proposed correlation and some other existing correlations of condensation heat transfer for pure refrigerant have been used to predict the condensation heat transfer of R1234ze(E), R32, R410A and dimethyl ether (DME) and compared the results. The comparison allows that the proposed model of pure refrigerant offered a better performance for all the refrigerants. All the experimental data can be predicted within a 10.2% mean deviation by using the proposed correlation.

  20. Theoretical model of film condensation in a bundle of horizontal low finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Hiroshi; Nozu, Shigeru; Takeda, Yasuhito

    1988-08-25

    A method for calculating flow behavior in a group of tubes was developed by modifying the calculation method for single tubes considering the flow characteristics of a condensate which flows down a series of vertical tubes with horizontal low fins, and the results of calculation by this method was compared with experimental values. The predicted value of the heat transfer coefficient obtained by calculation agreed well with values obtained by experiments with R12 and acetone. The theoretical values of n-butane and steam also agreed well with experimental values. According to the results of calculation given a practical condition, the heat transfer coefficient greatly depends on the fin spacing for R12 characterized by a low surface tension and a low condensation latent heat; also, it rapidly drops when the number of tubes exceeds a certain level if the fin spacing is narrow. The optimal fin spacing is about 0.3mm if the number of tubes is 2 to 15. For steam, the heat transfer coefficient increasing effect is considerably lower than for R12; the heat transfer coefficient does not vary so much with the fin spacing or the number of tubes; the optimal fin spacing is about 1.3mm. (6 figs, 11 refs)

  1. Experimental and theoretical study of horizontal tube bundle for passive condensation heat transfer

    Science.gov (United States)

    Song, Yong Jae

    The research in this thesis supports the design of a horizontal tube bundle condenser for passive heat removal system in nuclear reactors. From nuclear power plant containment, condensation of steam from a steam/noncondensable gas occurs on the primary side and boiling occurs on the secondary side; thus, heat exchanger modeling is a challenge. For the purpose of this experimental study, a six-tube bundle is used, where the outer diameter, inner diameter, and length of each stainless steel tube measures 38.10mm (1.5 inches), 31.75mm (1.25 inches) and 3.96m (156 inches), respectively. The pitch to diameter ratio was determined based on information gathered from literature surveys, and the dimensions were determined from calculations and experimental data. The objective of the calculations, correlations, and experimental data was to obtain complete condensation within the tube bundle. Experimental conditions for the tests in this thesis work were determined from Design Basis Accident (DBA). The applications are for an actual Passive Containment Cooling Systems (PCCS) condenser under postulated accident conditions in future light water reactors. In this research, steady state and transient experiments were performed to investigate the effect of noncondensable gas on steam condensation inside and boiling outside a tube bundle heat exchanger. The condenser tube inlet steam mass flow rate varied from 18.0 to 48.0 g/s, the inlet pressure varied from 100 kPa to 400 kPa, and the inlet noncondensable gas mass fraction varied from 1% to 10%. The effect of the noncondensable gas was examined by comparing the tube centerline temperatures for various inlet and system conditions. As a result, it was determined that the noncondensable gas accumulated near the condensate film causing a decrease of mass and energy transfer. In addition, the effect of the inlet steam flow rate gas was investigated by comparing the tube centerline temperatures, the conclusion being that, as the inlet

  2. Flow structure of natural dehumidification over a horizontal finned-tube

    Science.gov (United States)

    Hirbodi, Kamran; Yaghoubi, Mahmood

    2016-08-01

    In the present study, structure of water drops formation, growth, coalescence and departure over a horizontal finned-tube during natural dehumidification is investigated experimentally. Starting time of repelling the drops as well as heat transfer rate and the rate of dripping condensates in quasi-steady-state conditions are presented. Furthermore, cold airflow pattern around the horizontal finned-tube is visualized by using smoke generation scheme during natural dehumidification process. The finned-tube has a length of 300 mm, and inner and outer fin diameters, fin thickness and fin spacing are 25.4, 56, 0.4 and 2 mm, respectively. The tests are conducted in an insulated control room with dimensions of 5.8 m × 3 m × 4 m. Ambient air temperature, relative humidity and fin base temperature are selected from 25 to 35 °C, from 40 to 70 % and from 4 to 8 °C, respectively. Observations show that natural condensation from humid air over the test case is completely dropwise. Droplets only form on the edge of the fin and lateral fin surfaces remain almost dry. Dehumidification process over the tested finned-tube is divided into four stages; nucleation, formation, growth and departure of drops. It is also observed that the condensate inundation leaves the tube bottom in the form of droplets. Smoke visualization depicts that humid airflows downward around the cold finned-tube surface without noticeable turbulence and separation in the initial stages of dehumidification process. But the airflow has some disturbances in the intermediate stage and especially during drop departure on the edge of the fins.

  3. Establishment of Measurement Techniques for Sliding Bubble on a Horizontal Tube

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu-Na Kim; Park, Goon-Cherl; Cho, Hyoung-Kyu [Seoul National University, Seoul (Korea, Republic of)

    2015-10-15

    The mechanistic wall boiling model includes many parameters relevant with bubble behaviors, such as the bubble departure diameter, bubble lift-off diameter, bubble waiting time, etc. Although there have been a large number of studies investigating bubble behavior, the subjects of observation are almost bubbles on a plane or vertical tube. Since the bubble motion is highly influenced by the directions of gravitational force and the heating surfaces, it is expected that the bubble behavior on a horizontal tube is largely different from those on the other geometry. The heat exchanger of APR+ has horizontal U-tube configuration installed in a water pool, of which diameter is 50mm. The study aims to establish measurement techniques for sliding bubbles on a horizontal tube. The measurement parameters include the diameter, interface area, volume, and velocity of the bubble. Additionally, in order to analyze the force acting on the bubble, liquid velocity measurement method was proposed. This paper presents the procedure of the measurement; the phase separation technique, 3-D reconstruction technique, and velocity measurement techniques. For visualization of the sliding bubble behavior, bubble and liquid velocity measurement methods were established which use two high speed cameras and a continuous LASER for the PTV and PIV. Three steps for the bubble shape and velocity measurement (the phase separation, 3-D reconstruction, and velocity calculation), were successfully set up and verified. A PIV technique which uses two different time duration for two regions where the velocity difference is huge was proposed and tested. Using these methods, various information regarding a sliding bubble can be obtained such as bubble and liquid velocities, shape, volume, surface area etc.

  4. Analytical study in the mechanism of flame movement in horizontal tubes. II. Flame acceleration in smooth open tubes

    CERN Document Server

    Kazakov, Kirill A

    2013-01-01

    The problem of spontaneous acceleration of premixed flames propagating in open horizontal tubes with smooth walls is revisited. It is proved that in long tubes, this process can be considered quasi-steady, and an equation for the flame front position is derived using the on-shell description. Numerical solutions of this equation are found which show that as in the case of uniform flame movement, there are two essentially different regimes of flame propagation. In the type I regime, the flame speed and its acceleration are comparatively low, whereas the type II regime is characterized by significant flame acceleration that rapidly increases as the flame travels along the tube. A detailed comparison of the obtained results with the experimental data on flame acceleration in methane-air mixtures is given. In particular, it is confirmed that flames propagating in near-stoichiometric mixtures and mixtures near the limits of inflammability belong to the types II and I, respectively, whereas flames in transient mixt...

  5. Influence of stiffness on CHF for horizontal tubes under LPLF conditions

    Energy Technology Data Exchange (ETDEWEB)

    Baburajan, P.K. [Nuclear Safety Analysis Division, AERB, Niyamak Bhavan, 400094 (India); Bisht, Govind Singh [Department of Mechanical Engineering, IIT Bombay, 400076 (India); Gaikwad, Avinash J. [Nuclear Safety Analysis Division, AERB, Niyamak Bhavan, 400094 (India); Prabhu, S.V., E-mail: svprabhu@iitb.ac.in [Department of Mechanical Engineering, IIT Bombay, 400076 (India)

    2014-10-01

    Highlights: • Effect of stiffness on the CHF in horizontal tube under LPLF conditions is studied. • CHF increases with the increase in stiffness. • Correlation for the prediction of CHF as a function of stiffness is developed. • Correlation for mass flux at CHF in terms of stiffness and initial mass flux is given. • RELAP5 is capable of predicting the effect of stiffness on CHF. - Abstract: Studies reported in the past on critical heat flux (CHF) are mostly limited to vertical flow, large channel diameter, high pressure and high mass flux. Since horizontal flow is commonly encountered in boiler tubes, refrigerating equipments and nuclear reactor fuel channels (PHWR), there is a need to understand horizontal flow CHF, generate sufficient experimental database and to develop reliable predictive method. Few studies are reported on the effect of upstream flow restrictions on flow instabilities and CHF. The present work investigates the effect of upstream flow restriction on CHF in horizontal flow at near atmospheric pressure conditions. In the present study, stiffness is defined as the ratio of upstream flow restriction pressure drop to the test section pressure drop. The classification of a flow boiling system as soft or stiff on the basis of quantification of the stiffness is attempted. Experimental data shows an increase in the CHF with the increase in the stiffness for a given initial mass flux. A correlation for the prediction of CHF under various stiffness conditions is developed. A correlation is suggested to predict the mass flux at CHF as a function of stiffness and initial mass flux. Modeling and transient analysis of the stiffness effect on CHF is carried out using the thermal hydraulic system code RELAP5. The predicted phenomena are in agreement with the experimental observations.

  6. Experimental Investigation of Forced Convective Boiling Flow Instabilities in Horizontal Helically Coiled Tubes

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    An experimental investigation is described for the characteristics of convective boiling flow instabilities in horizontally helically coiled tubes using a steam-water two-phase closed circulation test loop at pressure from 0.5 MPa to 3.5MPa.Three kinds of oscillation are reported.density waves;pressure drop excorsions;thermal fluctuations.We describe their dependence on main system parameters such as system pressure,mass flowrate,inlet subcooling,compressible volume and heat flux.Utilising the experimental data together with conservation constraints,a dimensionless correlation is proposed for the occurrence of density waves.

  7. Experimental study on film combustion formed by spirally fluted horizontal tube

    Institute of Scientific and Technical Information of China (English)

    Ning MEI; Bin ZHANG; Jian ZHAO; Ming ZHANG

    2008-01-01

    Falling fuel film on the spirally fluted surface of a horizontal tube can provide rapid fuel evaporation and homogeneous mixture formation. This fuel film combus-tion could be applied in a micro-combustion system even without a fuel pump. A test bed was established and experimental comparisons were made between the pro-totype and a transferred cup atomizer micro-combustor. The theoretical and experimental results show that film combustion has a higher combustion efficiency, a lower pollutant emission and a better working performance.

  8. Experimental study on heat transfer characteristics of supercritical carbon dioxide in horizontal tube

    Institute of Scientific and Technical Information of China (English)

    Jing LV; Meng FU; Na QIN; Bin DONG

    2008-01-01

    The heat transfer characteristics of supercrit-ical carbon dioxide in a horizontal tube with water in the vertical cross flow form were experimentally investi-gated. The results indicate that the changes of inlet pres-sure, mass flow rate, and cooling water flow rate have major effects on heat transfer performance. The varia-tions of Reynolds number and Prandtl number were obtained in counter flow and vertical cross flow. The four conventional correlations for convection heat transfer of supercritical carbon dioxide were verified by the experi-mental data in this study and the correlation agree with this experimental condition was determined.

  9. Heat transfer enhancement of PCM melting in 2D horizontal elliptical tube using metallic porous matrix

    Science.gov (United States)

    Jourabian, Mahmoud; Farhadi, Mousa; Rabienataj Darzi, Ahmad Ali

    2016-07-01

    In this study, the melting process of ice as a phase-change material (PCM) saturated with a nickel-steel porous matrix inside a horizontal elliptical tube is investigated. Due to the low thermal conductivity of the PCM, it is motivated to augment the heat transfer performance of the system simultaneously by finding an optimum value of the aspect ratio and impregnating a metallic porous matrix into the base PCM. The lattice Boltzmann method with a double distribution function formulated based on the enthalpy method, is applied at the representative elementary volume scale under the local thermal equilibrium assumption between the PCM and porous matrix in the composite. While reducing or increasing the aspect ratio of the circular tubes leads to the expedited melting, the 90° inclination of each elliptical tube in the case of the pure PCM melting does not affect the melting rate. With the reduction in the porosity, the effective thermal conductivity and melting rate in all tubes promoted. Although the natural convection is fully suppressed due to the significant flow blockage in the porous structure, the melting rates are generally increased in all cases.

  10. Heat transfer enhancement of PCM melting in 2D horizontal elliptical tube using metallic porous matrix

    Science.gov (United States)

    Jourabian, Mahmoud; Farhadi, Mousa; Rabienataj Darzi, Ahmad Ali

    2016-12-01

    In this study, the melting process of ice as a phase-change material (PCM) saturated with a nickel-steel porous matrix inside a horizontal elliptical tube is investigated. Due to the low thermal conductivity of the PCM, it is motivated to augment the heat transfer performance of the system simultaneously by finding an optimum value of the aspect ratio and impregnating a metallic porous matrix into the base PCM. The lattice Boltzmann method with a double distribution function formulated based on the enthalpy method, is applied at the representative elementary volume scale under the local thermal equilibrium assumption between the PCM and porous matrix in the composite. While reducing or increasing the aspect ratio of the circular tubes leads to the expedited melting, the 90° inclination of each elliptical tube in the case of the pure PCM melting does not affect the melting rate. With the reduction in the porosity, the effective thermal conductivity and melting rate in all tubes promoted. Although the natural convection is fully suppressed due to the significant flow blockage in the porous structure, the melting rates are generally increased in all cases.

  11. Remote field eddy current technique for gap measurement of horizontal flux detector guide tube in pressurized heavy water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Hoon; Jung, Hyun Kyu; Yang, Dong Ju; Cheong, Yong Moo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2004-11-15

    The fuel channels including the pressure tube(PT) and the calandria tube(CT) are important components of the pressurized heavy water reactor(PHWR). A sagging of fuel channel increases by heat and radiation exposure with the increasing operation time. The contact of fuel channel to the Horizontal flux Detector(HFD) guide tube is needed for the power plant safety. In order to solve this safety issue, the electromagnetic technique was applied to measure the status of the guide tube. The Horizontal flux Detector(HFD) guide tube and the Calandria tube(CT) in the Pressurized Heavy Water Reactor(PHWR) are cross-aligned horizontally. The remote field eddy current(RFEC) technology is applied for gap measurement between the HFD guide tube and the CT HFD guide tube can be detected by inserting the RFEC probe into pressure tube(PT) at the crossing point directly. The RFEC signals using the volume integral method(VIM) were simulated for obtaining the optimal inspection parameters. This paper shows that the simulated eddy current signals and the experimental results in variance with the CT/HFD gap.

  12. Film condensation of downward flowing R-113 vapor on in-line bundles of horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Hiroshi; Uchima, Bunken; Nozu, Shigeru; Nakata, Hironori; Torigoe, Eiichi (Okayama Univ., Faculty of Engineering, Okayama, (Japan))

    1989-08-25

    The film condensation characteristics of a downward flowing R-113 vapor on in-line bundles of horizontal finned tubes were experimentally investigated using two tubes with flat-sided fins and four tubes with three-dimensional fins. The flow pattern of falling condensate on the finned tube bundle is similar to that on the smooth tube bundle, basically. The liquid filled position of tube with flat-sided fins is not affected by the vapor velocity. The effect of the vapor velocity on the film condensation in the finned tube bundle was considerably smaller than the case of the smooth tube bundle. The decrease of the heat transfer coefficient due to the condensate inundation was larger in case of the tubes with three-dimensional fins than in case of the tubes with flat-sided fins. While the tubes with three-dimensional fins showed contrary tendency against the tubes with flat-sided fins. Among six sample tubes, a tube with flat-sided fins of 0.5mm fin pitch and 1.3mm fin height showed the best heat transfer performance over the range of the whole experiment. 16 refs., 11 figs., 2 tabs.

  13. Experiments on Void Fraction of CO2 Flow Boiling in a Horizontal Micro-fin Tube

    Science.gov (United States)

    Kondou, Chieko; Higashiiue, Shinya; Kuwahara, Ken; Koyama, Shigeru

    This paper deals with an experimental investigation on the void fraction of CO2 flow boiling in a horizontal micro-fin tube. The mean void fraction in the insulated 400 mm length sampling section, which is located next to the test evaporator, has measured by the quick closing valve method. The experimental data have been obtained in mass flux range of 200 to 455 kg/(m2s) and the refrigerant pressure range of 3.5 to 5.0 MPa. It is confirmed that the relation between void fraction and quality is affected by both mass flux and pressure. The experimental results are also compared with two previous correlations for horizontal smooth tubes, which are proposed by Butterworth and Smith. The present data satisfactorily agreed with Butterworth's correlation in the range of quality from 0.03 to 0.99. However, Smith's correlation is found to predict slightly higher than present data. As a trial, the empirical correlation of void fraction, based on the experimental slip ratios, is proposed.

  14. Numerical investigation of supercritical LNG convective heat transfer in a horizontal serpentine tube

    Science.gov (United States)

    Han, Chang-Liang; Ren, Jing-Jie; Dong, Wen-Ping; Bi, Ming-Shu

    2016-09-01

    The submerged combustion vaporizer (SCV) is indispensable general equipment for liquefied natural gas (LNG) receiving terminals. In this paper, numerical simulation was conducted to get insight into the flow and heat transfer characteristics of supercritical LNG on the tube-side of SCV. The SST model with enhanced wall treatment method was utilized to handle the coupled wall-to-LNG heat transfer. The thermal-physical properties of LNG under supercritical pressure were used for this study. After the validation of model and method, the effects of mass flux, outer wall temperature and inlet pressure on the heat transfer behaviors were discussed in detail. Then the non-uniformity heat transfer mechanism of supercritical LNG and effect of natural convection due to buoyancy change in the tube was discussed based on the numerical results. Moreover, different flow and heat transfer characteristics inside the bend tube sections were also analyzed. The obtained numerical results showed that the local surface heat transfer coefficient attained its peak value when the bulk LNG temperature approached the so-called pseudo-critical temperature. Higher mass flux could eliminate the heat transfer deteriorations due to the increase of turbulent diffusion. An increase of outer wall temperature had a significant influence on diminishing heat transfer ability of LNG. The maximum surface heat transfer coefficient strongly depended on inlet pressure. Bend tube sections could enhance the heat transfer due to secondary flow phenomenon. Furthermore, based on the current simulation results, a new dimensionless, semi-theoretical empirical correlation was developed for supercritical LNG convective heat transfer in a horizontal serpentine tube. The paper provided the mechanism of heat transfer for the design of high-efficiency SCV.

  15. Effect of Fin Geometry on Condensation of R134a in a Staggered Bundle of Horizontal Finned Tubes

    Science.gov (United States)

    Honda, Hiroshi; Takata, Nobuo; Takamatsu, Hiroshi; Kim, Jeongsk; Usami, Keiichiro

    Experimental results are presented that show the effect of fin geometry on condensation of refrigerant R134a in a staggered bundle of horizontal fined tubes. Two kinds of conventional low-fin tubes and three kinds of three-dimensional fin tubes were tested. The refrigerant mass velocity ranged from 8 to 23 kg/m2s and the condensation temperature difference from 1.5 to 12 K. In most cases, the highest performance was obtained by one of the three-dimensional fin tubes. In the case of high mass velocity and high film Reynolds number, however, the highest performance was obtained by one of the low-fin tubes. The results were compared with previous experimental results for bundles of smooth tubes and low-fin tubes.

  16. Selection criteria for plain and segmented finned tubes for heat recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Reid, D.R. (FINTUBE Corp., Tulsa, OK (United States)); Taborek, J. (Taborek (J.), Virginia Beach, VA (United States))

    1994-04-01

    Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded plain'' fins were generally used in the past, until the high-frequency resistance welding technology permitted a cost-effective manufacture of segmented'' fins. The main advantage of this fin design (Fig. 1) is that it permits higher heat flux and hence smaller, lighter weight units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight, and cost per unit area favor the segmented fin design, a few other considerations such as fouling, ease of cleaning, and availability of dependable design methods have to be considered. This paper analyzes the performance parameters that affect the selection of either fin type.

  17. Selection criteria for plain and segmented finned tubes for heat recovery systems

    Science.gov (United States)

    Reid, D. R.; Taborek, J.

    1994-04-01

    Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded 'plain' fins were generally used in the past, until the high-frequency resistance welding technology permitted a cost-effective manufacture of 'segmented' fins. The main advantage of this fin design is that it permits higher heat flux and hence smaller, lighter weight units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight, and cost per unit area favor the segmented fin design, a few other considerations such as fouling, ease of cleaning, and availability of dependable design methods have to be considered. This paper analyzes the performance parameters that affect the selection of either fin type.

  18. Bundle impact with th condensation of propane at horizontal smooth tubes and finned tubes; Buendeleffekt bei der Kondensation von Propan an horizontalen Glatt- und Rippenrohren

    Energy Technology Data Exchange (ETDEWEB)

    Gebauer, Thomas; Leipertz, Alfred; Froeba, Andreas Paul [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Technische Thermodynamik (LTT); Gotterbarm, Achim; El Hajal, Jean [Wieland-Werke AG, Ulm (Germany)

    2012-07-01

    With respect to a basic description of the bundling impact in tube bundle condensers, the authors of the contribution under consideration report on the impact of the material properties of the working fluid, tube structure and tube material on the heat transfer. For this, the existing experimental database on the condensate side heat transfer coefficient with 1.1.1.2-tetrafluoroethane (R134a) has been extended by the natural refrigerant propane (R290). In addition to plain tubes, standard finned tubes and high-performance finned tubes consisting of copper, ribbed and grooved steel finned tubes were used. The experimental condensation tests were carried out at the outside of the tube at a saturation temperature of 37 Celsius. By expanding the data base, both analytical models and a CFD model for predicting the condensate side heat transfer coefficient on the smooth and finned tube a well as corresponding single tube bundles could be verified. The results on single smooth tube showed a very good agreement between the condensate side heat transfer coefficients of propane and R134a with the Nusselt theory. The largest side condensate heat transfer coefficients were determined at the single high-performance finned tube made of copper and the corresponding tube bundle with R134a. Compared to the standard finned tubes of both materials, the high-performance finned copper tubes showed a greater bundling effect for both working fluids. Unlike R134a, almost no differences were observed for the experimentally determined behavior of the bundle on standard finned tubes and high-performance finned tube made of steel with propane. The condensation side heat transfer coefficients on the latter two tubes were below the values for the finned copper tubes with propane. The CFD simulations for the single tube were within the experimental uncertainties. In the case of the investigations of bundles, the modeled data showed a larger deviation from the experimental data than the

  19. Stress distribution in maxillary first molar periodontium using straight pull headgear with vertical and horizontal tubes: A finite element analysis.

    Science.gov (United States)

    Feizbakhsh, Masood; Kadkhodaei, Mahmoud; Zandian, Dana; Hosseinpour, Zahra

    2017-01-01

    One of the most effective ways for distal movement of molars to treat Class II malocclusion is using extraoral force through a headgear device. The purpose of this study was the comparison of stress distribution in maxillary first molar periodontium using straight pull headgear in vertical and horizontal tubes through finite element method. Based on the real geometry model, a basic model of the first molar and maxillary bone was obtained using three-dimensional imaging of the skull. After the geometric modeling of periodontium components through CATIA software and the definition of mechanical properties and element classification, a force of 150 g for each headgear was defined in ABAQUS software. Consequently, Von Mises and Principal stresses were evaluated. The statistical analysis was performed using T-paired and Wilcoxon nonparametric tests. Extension of areas with Von Mises and Principal stresses utilizing straight pull headgear with a vertical tube was not different from that of using a horizontal tube, but the numerical value of the Von Mises stress in the vertical tube was significantly reduced (P 0/05). Based on the results, when force applied to the straight pull headgear with a vertical tube, Von Mises stress was reduced significantly in comparison with the horizontal tube. Therefore, to correct the mesiolingual movement of the maxillary first molar, vertical headgear tube is recommended.

  20. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-07-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidizing gas,(3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  1. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-10-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidising gas, (3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger, and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  2. Wintering bats of the upper Snake River Plain: occurrence in lava-tube caves

    Energy Technology Data Exchange (ETDEWEB)

    Genter, D.L.

    1986-04-30

    Distribution and habitat selection of hibernating bats at the Idaho National Engineering Laboratory (INEL) and adjacent area are reported. Exploration of over 30 lava-tube caves revealed that two species, Myotis leibii and Plecotus townsendii, hibernate in the upper Snake River Plain. Five species, M. lucifugus, M. evotis, Eptesicus fuscus, Lasionycteris noctivagans, and Lasiurus cinereus are considered migratory. Myotis leibii and P. townsendii hibernate throughout much of the area, occasionally in mixed-species groups. Myotis leibii uses the dark and protected regions of the cave, usually wedged into tiny pockets and crevices near or at the highest portion of the ceiling. Individuals of P. townsendii may be found at any height or depth in the cave. Temperature appears to be primary limiting factor in habitat selection. Myotis leibii was found in significantly cooler air temperatures than P. townsendii. Neither species tolerated continuous temperatures below 1.5 C. Relative humidity does not seem to be a significant factor in the distribution or habitat selection of the two species in lava-tube caves. 18 references, 1 figure, 1 table.

  3. Numerical Study on the Heat Transfer of Carbon Dioxide in Horizontal Straight Tubes under Supercritical Pressure.

    Directory of Open Access Journals (Sweden)

    Mei Yang

    Full Text Available Cooling heat transfer of supercritical CO2 in horizontal straight tubes with wall is numerically investigated by using FLUENT. The results show that almost all models are able to present the trend of heat transfer qualitatively, and the stand k-ε with enhanced wall treatment model shows the best agreement with the experimental data, followed by LB low Re turbulence model. Then further studies are discussed on velocity, temperature and turbulence distributions. The parameters which are defined as the criterion of buoyancy effect on convection heat transfer are introduced to judge the condition of the fluid. The relationships among the inlet temperature, outlet temperature, the mass flow rate, the heat flux and the diameter are discussed and the difference between the cooling and heating of CO2 are compared.

  4. Liquid Sloshing in a Horizontal Circular Container with Eccentric Tube under External Excitation

    Directory of Open Access Journals (Sweden)

    Mohammad Nezami

    2014-01-01

    Full Text Available Appropriate conformal mapping transformation in combination with the linear potential theory is employed to develop mathematical model for two-dimensional sloshing in horizontal circular cylindrical containers with overall eccentric hole. The tube-type tank is filled with inviscid incompressible fluid up to its half depth and subjected to lateral accelerations. A ramp-step excitation encountered in a road turning maneuver as well as real seismic event is used to simulate the lateral acceleration excitation. The resulting linear sets of ordinary differential equations are truncated and then solved numerically by employing Laplace transform technique followed by Durbin’s numerical inversion pattern. The effects of excitation input time, eccentricity, and radii ratio on the hydrodynamic responses and suppression of the induced destabilizing lateral forces are examined. Limiting cases are considered and good agreements with available analytic and numerical solutions as well as the simulations performed by using a commercial FEM software package are obtained.

  5. Surface-particle-emulsion heat transfer model between fluidized bed and horizontal immersed tube

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A mathematical model, surface-particle-emulsion heat transfer model, is presented by considering voidage variance in emulsion in the vicinity of an immersed surface. Heat transfer near the surface is treated by dispersed particles touching the surface and through the emulsion when the distance from the surface is greater than the diameter of a particle. A film with an adjustable thickness which separates particles from the surface is not introduced in this model. The coverage ratio of particles on the surface is calculated by a stochastic model of particle packing density on a surface. By comparison of theoretical solutions with experimental data from some references, the mathematical model shows better qualitative and quantitative prediction for local heat transfer coefficients around a horizontal immersed tube in a fluidized bed.

  6. Numerical Study on the Heat Transfer of Carbon Dioxide in Horizontal Straight Tubes under Supercritical Pressure.

    Science.gov (United States)

    Yang, Mei

    2016-01-01

    Cooling heat transfer of supercritical CO2 in horizontal straight tubes with wall is numerically investigated by using FLUENT. The results show that almost all models are able to present the trend of heat transfer qualitatively, and the stand k-ε with enhanced wall treatment model shows the best agreement with the experimental data, followed by LB low Re turbulence model. Then further studies are discussed on velocity, temperature and turbulence distributions. The parameters which are defined as the criterion of buoyancy effect on convection heat transfer are introduced to judge the condition of the fluid. The relationships among the inlet temperature, outlet temperature, the mass flow rate, the heat flux and the diameter are discussed and the difference between the cooling and heating of CO2 are compared.

  7. Evaporation heat transfer of carbon dioxide at low temperature inside a horizontal smooth tube

    Science.gov (United States)

    Yoon, Jung-In; Son, Chang-Hyo; Jung, Suk-Ho; Jeon, Min-Ju; Yang, Dong-Il

    2016-10-01

    In this paper, the evaporation heat transfer coefficient of carbon dioxide at low temperature of -30 to -20 °C in a horizontal smooth tube was investigated experimentally. The test devices consist of mass flowmeter, pre-heater, magnetic gear pump, test section (evaporator), condenser and liquid receiver. Test section is made of cooper tube. Inner and outer diameter of the test section is 8 and 9.52 mm, respectively. The experiment is conducted at mass fluxes from 100 to 300 kg/m2 s, saturation temperature from -30 to -20 °C. The main results are summarized as follows: In case that the mass flux of carbon dioxide is 100 kg/m2 s, the evaporation heat transfer coefficient is almost constant regardless of vapor quality. In case of 200 and 300 kg/m2 s, the evaporation heat transfer coefficient increases steadily with increasing vapor quality. For the same mass flux, the evaporation heat transfer coefficient increases as the evaporation temperature of the refrigerant decreases. In comparison of heat transfer correlations with the experimental result, the evaporation heat transfer correlations do not predict them exactly. Therefore, more accurate heat transfer correlation than the previous one is required.

  8. A Numerical Analysis of the Forced Convection Condensation of Saturated Vapor Flowing Axially Outside a Horizontal Tube

    Institute of Scientific and Technical Information of China (English)

    WeizhongLi; WeichengWang; 等

    1995-01-01

    Physical and mathematical models are developed to describe the forced convection condensation heat transfer of saturated vapor flowing axially outside a horizontal tube.The numerical solution of the models indicates the effects of vapor velocity on the liquid film thickness.The result verifies the enhancement of condensation heat transfer caused by such flow.

  9. Improvements of the experimental apparatus for measurement of the surface tension of supercooled liquids using horizontal capillary tube

    Directory of Open Access Journals (Sweden)

    Vinš Václav

    2016-01-01

    Full Text Available An experimental apparatus with a horizontal capillary tube for measurement of the surface tension of supercooled liquids, i.e. liquids in a metastable state below the equilibrium freezing point, was designed and tested in the previous study [V. Vinš et al., EPJ Web Conf. 92, 02108 (2015]. In this work, recent modifications of both the experimental setup and the measurement analysis are described. The main aim is to improve the accuracy and the reproducibility of measured surface tension and to achieve higher degrees of supercooling. Temperature probes measuring the temperature of cooling medium near the horizontal capillary tube were calibrated in the relevant temperature range from – 31 °C to + 45 °C. An additional pressure transducer was installed in the helium distribution setup at the position close to the capillary tube. The optical setup observing the liquid meniscus at the open end of the horizontal capillary tube together with the video analysis were thoroughly revised. The red laser illuminating the liquid meniscus, used at the original apparatus, was replaced by a fiber optic light source, which significantly improved the quality of the meniscus image. The modified apparatus was used for the measurement of surface tension of supercooled water at temperatures down to – 11 °C. The new data have a lower scatter compared to the previous horizontal measurements and show a good agreement with the other data obtained with a different measurement technique based on the modified capillary rise method.

  10. Influence of surface roughness and tube diameter on pool boiling at single plain and finned tubes. Zum Einfluss der Oberflaechenrauhigkeit und des Rohrdurchmessers beim Blasensieden an einzelnen Glatt- und Rippenrohren

    Energy Technology Data Exchange (ETDEWEB)

    Gorenflo, D.; Schoemann, H.; Sokol, P.; Caplanis, S. (Paderborn Univ. (Gesamthochschule) (Germany, F.R.). Lab. fuer Waerme- und Kaeltetechnik)

    1990-09-18

    Heat transfer with pool boiling of hexane was measured for single-plain and finned steel tubes with great diameter and very rough, sandblasted surface. The results show that the heat transfer coefficients calculated for the outer surfaces of both tubes are higher in the case of the finned tube at high heat fluxes, and gradually diminish down to the values of the plain tube until natural convection without bubble formation has been reached. Additional measurements using a plain tube with much smaller diameter but identical surface treatment indicate that great differences of the tube diameter influence the increase of the heat transfer coefficient with heat flux significantly, the relative pressure dependence and the absolute values of the heat transfer coefficient at intermediate heat fluxes, however, are concerned on a smaller scale. (orig.).

  11. Characterization of Dosimetry of the BMRR Horizontal Thimble Tubes and Broad Beam Facility.

    Energy Technology Data Exchange (ETDEWEB)

    Hu,J.P.; Reciniello, R.N.; Holden, N.E.

    2008-05-05

    The Brookhaven Medical Research Reactor was a 5 mega-watt, light-water cooled and heavy-graphite moderated research facility. It has two shutter-equipped treatment rooms, three horizontally extended thimble tubes, and an ex-core broad beam facility. The three experimental thimbles, or activation ports, external to the reactor tank were designed for several uses, including the investigations on diagnostic and therapeutic methods using radioactive isotopes of very short half-life, the analysis of radiation exposure on tissue-equivalent materials using a collimated neutron beam, and the evaluation of dose effects on biological cells to improve medical treatment. At the broad beam facility where the distribution of thermal neutrons was essential uniform, a wide variety of mammalian whole-body exposures were studied using animals such as burros or mice. Also studied at the broad beam were whole-body phantom experiments, involving the use of a neutron or photon beam streaming through a screen to obtain the flux spectrum suitable for dose analysis on the sugar-urea-water mixture, a tissue-equivalent material. Calculations of the flux and the dose at beam ports based on Monte Carlo particle-transport code were performed, and measurements conducted at the same tally locations were made using bare or cadmium-covered gold foils. Analytical results, which show good agreement with measurement data, are presented in the paper.

  12. Experimental study on the minimum drag coefficient of supercritical pressure water in horizontal tubes

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Xianliang, E-mail: xianlianglei@mail.xjtu.edu.cn; Li, Huixiong; Guo, YuMeng; Zhang, Qing; Zhang, Weiqiang; Zhang, Qian

    2016-05-15

    Highlights: • The minimum drag coefficient phenomenon (MDC) has been observed and further investigated. • Effects of heat flux, mass flux and pressure to MDC have been discussed. • A series of comparisons between existing correlations and data have been conducted. • Two correlations of drag coefficient are proposed for isothermal and nonisothermal flow. - Abstract: Hydraulic resistance and its components are of great importance for understanding the turbulence nature of supercritical fluid and establishing prediction methods. Under supercritical pressures, the hydraulic resistance of the fluid exhibits a “pit” in the regions near its pseudo-critical point, which is hereafter called the minimum drag coefficient phenomenon. However, this special phenomenon was paid a little attention before. Hence systematical experiments have been carried out to investigate the hydraulic resistance of supercritical pressure water in both adiabatic and heated horizontal tubes. Parametric effects of heat flux, pressure and mass fluxes to drag coefficient are further compared. It is found that almost all of the existing correlations don’t agree well with the experimental data due to the insufficient consideration of thermal-properties near the pseudocritical point. Two correlations of the drag coefficients are finally proposed by introducing the new variable of the derivative of density with respect to temperature or Prandtl number, which can better predict the drag coefficient of isothermal and nonisothermal flow respectively.

  13. Effects of dynamic contact angle on liquid infiltration into horizontal capillary tubes: (semi)-analytical solutions.

    Science.gov (United States)

    Hilpert, Markus

    2009-09-01

    We generalize Washburn's analytical solution for capillary flow in a horizontally oriented tube by accounting for a dynamic contact angle. We consider two general models for dynamic contact angle: the uncompensated Young force on the contact line depends on the capillary number in the form of either (1) a power law with exponent beta or (2) a power series. By considering the ordinary differential equation (ODE) for the velocity of the gas-liquid interface instead of the ODE for the interface position, we are able to derive new analytical solutions. For both dynamic contact angle models, we derive analytical solutions for the travel time of the gas-liquid interface as a function of interface velocity. The interface position as a function of time can be obtained through numerical integration. For the power law and beta=1 (an approximation of Cox's model for dynamic contact angle), we obtain an analytical solution for both interface position and velocity as a function of time. For the power law and beta=3, we can express the interface velocity as a function of time.

  14. Effects of Adding Nanoparticles on Boiling and Condensing Heat Transfer inside a horizontal round tube

    Science.gov (United States)

    Sheikholeslami, Mohsen; Sadoughi, Mohammadkazem; Shariatmadar, Hamed; Akhavan-Behabadi, Mohammad Ali

    2015-11-01

    An experimental investigation is performed on heat transfer evaluation of a nano-refrigerant flow during condensation and evaporation inside a horizontal round tube. Experiments are carried out for three working fluid types including: i) pure refrigerant (R600a); ii) refrigerant/lubricant (R600a/oil); and iii) nano-refrigerant: refrigerant/lubricant/nanoparticles (R600a/oil/CuO). Nanoparticles are added to the lubricant and their mixture is mixed with pure refrigerant. Therefore, nano-refrigerants (R600a/oil/CuO) are prepared by dispersing CuO nanoparticles with different fractions of 0.5%, 1% and 1.5% in the baseline mixture (R600a/oil). Effects of different factors including vapor quality, mass flux, and nanoparticles on the heat transfer coefficient are examined for both of condensation and evaporation flows, separately. The results shows that maximum heat transfer augmentation of 79% and 83% are achieved by using the refrigerant/lubricant/nanoparticles mixture, in comparison with the pure refrigerant case in condensation and evaporation, respectively which are occurred for nano-refrigerant with 1.5% mass fraction in both of them.

  15. Horizontal

    Institute of Scientific and Technical Information of China (English)

    ZHONG; Chunping

    2005-01-01

    [1]Wu, H., Bochner technique in differential geometry, Advance in Math. (in Chinese), 1981, 10(1): 57-76.[2]Morrow, J., Kodaira, K., Complex Manifolds, New York: Holt, Rinehart & Winston, 1971.[3]Abate, M., Aikou, T., Patrizio, G., Preface for Complex Finsler Geometry, Cont. Math., Vol. 196, Providence,RI: Amer. Math. Soc., 1996, 97-100.[4]Abate, M., Patrizio, G., Finsler Metrics-A global approach with applications to geometric function theory,Lecture Notes in Mathematics, Vol. 1591, Bedin: Springer-Verlag, 1994.[5]Antonelli, P. L., Lackey, B.(eds.), The Theory of Finslerian Laplacians and Applications, MAIA 459, Dordrecht:Kluwer Academic Publishers, 1998.[6]Bao, D., Lackey, B., A Hodge decomposition theorem for Finsler spaces, C. R. Acad. Sci. Paris, t. 323, Serie 1,1996, 51-56.[7]Munteanu, O., Weitzenbock formulas for horizontal and vertical Laplacians, Houston Journal of Mathematics,2003, 29(4): 889-900.[8]Faran, J. J., The equivalence problem for complex Finsler Hamiltonians, Cont. Math.,Vol. 196, Providence, RI:Amer. Math. Soc., 1996, 133-144.[9]Kobayashi, S., Complex Finsler vector bundles, Cont. Math., Vol. 196, Providence, RI: Amer. Math. Soc.,1996,145-153.[10]Aikou, T., On complex Finsler manifolds, Rep. Fac. Sci. Kagoshima Univ. (Math. Phys. & Chem.), 1991, 24:9-25.

  16. Horizontal monitoring of soil water content using a novel automated and mobile electromagnetic access-tube sensor

    Science.gov (United States)

    Sun, Y.; Zhou, H.; Qin, Y.; Schulze Lammers, P.; Berg, A.; Deng, H.; Cai, X.; Wang, D.; Jones, S. B.

    2014-08-01

    Advances in sensor technology continue to provide new and significant benefits to agriculture. An innovative approach for observing soil water dynamics in the subsurface is introduced using a mobile electromagnetic sensor prototype traveling through a horizontal PVC access tube. A series of tests for evaluating the prototype were designed and conducted to (i) determine the sensor's area of sensitivity (AOS), (ii) measure varied levels of soil water content along the tube and (iii) track temporal changes in soil water content under; (a) two drippers on a horizontal- and (b) multiple drippers on a sloped-soil surface (i.e., 6° slope). The AOS experiment suggested the sensor's fringing field extends to a radius of 5.5 cm from the pipe wall yielding an AOS of 181.3 cm2. Measured step-wise changes in soil water content along the tube were highly correlated to those of extracted core samples (R2 = 0.99 and RMSE = 0.012 cm3 cm-3). The drip emitter tests illustrated spatial hydrodynamics of water infiltration around the access tube. These results illustrate potential applications for this sensing approach, yielding one-dimensional monitoring of soil water along a horizontal line in the root zone or deeper subsurface. Future developments should explore performance in longer and potentially curvilinear pipes for environmental and engineering applications.

  17. Evaluation and control of corrosion and encrustation in tube wells of the Indus Plains, West Pakistan

    Science.gov (United States)

    Clarke, Frank Eldridge; Barnes, Ivan

    1969-01-01

    Seepage from rivers and irrigation canals has contributed to waterlogging and soil salinization problems in much of the Indus Plains of West Pakistan. These problems are being overcome in part by tube-well dewatering and deep leaching of salinized soils. The ground waters described here are anaerobic and some are supersaturated with troublesome minerals such as calcium carbonate (calcite) and iron carbonate (siderite). These waters are moderately corrosive to steel. Some wells contain sulfate-reducing bacteria, which catalyze corrosion, and pH-electrode potential relationships favorable to the solution of iron also are rather common. Corrosion is concentrated in the relatively active (anodic) saw slots of water-well filter pipes (screens), where metal loss is least tolerable. Local changes in chemical properties of the water, because of corrosion, apparently cause deposition of calcium carbonate, iron carbonate, and other minerals which clog the filter pipes. In some places well capacities are seriously reduced in very short periods of time. There appears to be no practicable preventive treatment for corrosion and encrustation in these wells. Even chemical sterilization for bacterial control has yielded poor results. Periodic rehabilitation by down-hole blasting or by other effective mechanical or chemical cleaning methods will prolong well life. It may be possible to repair severely damaged well screens by inserting perforated sleeves of plastic or other inert material. The most promising approach to future, well-field development is to use filter pipes of epoxy-resin-bonded fiber glass, stainless steel, or other inert material which minimizes both corrosion and corrosion-catalyzed encrustation. Fiberglass plastic pipe appears to be the most economically practicable construction material at this time and already is being used with promising results.

  18. Heat transfer and pressure drop characteristics of plain finned heat exchangers having 5.0 mm tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nae Hyun; Ham, Jung Ho; Oh, Wang Ku [Incheon Univ., Incheon (Korea, Republic of); Choi, Yong Hwa; Gaku, Hayase [Samsung Electric Company, Suwon (Korea, Republic of)

    2007-07-01

    In this study, pressure drop and heat transfer characteristics of plain finned heat exchangers having 5.0 diameter (fin collar 5.3 mm) tubes were investigated. Six samples having different fin pitches and tube rows were tested. The fin pitch had a negligible effect on j and f factors. Both j and f factors decreased as the number of tube row increased, although the difference was not significant for the f factor. When compared with the previous 7.3 mm diameter data, both the present j and f factors yielded lower values. However, the j/f ratio was larger at low Reynolds numbers. Possible reasoning is provided from the flow pattern consideration. Comparison with existing correlations were made.

  19. Effects of Working Fluid,Tubeside Enhancement and Bundle Depth on the Optimized Fin Geometry of a Horizontal Condenser Tube

    Institute of Scientific and Technical Information of China (English)

    H.Honda; T.Fukuda

    1992-01-01

    A theoretical study has been made to optimize the fin geometry of a horizontal finned tube which is to be used for condensers that handle the vapor load of a liquid phase change cooling module,Systematic numerical calculations of the vapor to coolant heat transfer coefficinet.Three dielctric fluids(R-113,FC-72,and FC-87) at atmospheric pressure were selected as the working fluids.For a single tube with optimized fin geometry,the average heat flux increased in the order of FC-87,R-113 and FC-72.Both the optimum fin height and optimum fin spacing incresaed with increasing vertical bundle depth.

  20. A simple physical model for steam absorption into a falling film of aqueous lithium bromide solution on a horizontal tube

    Science.gov (United States)

    Auracher, Hein; Wohlfeil, Arnold; Ziegler, Felix

    2008-03-01

    For one horizontal tube in an absorber the Nusselt solution for film thickness and velocity distribution was applied, assuming steady state in heat transfer and a semi-infinite body’s concentration profile with unsteady state mass transfer. The model was applied to the absorption of steam into aqueous lithium bromide in absorption chillers. The results are compared to published experimental values and show fair agreement.

  1. Experimental Study on Condensation of Pure Refrigerants in Horizontal Micro-fin Tubes

    Science.gov (United States)

    Yonemoto, Ryuichiro; Koyama, Shigeru

    This paper presents the heat transfer and pressure drop correlations for condensation in micro-fin tubes. Experimental data for eleven micro-fin tubes with different fin dimensions were used, and the refrigerants tested were R22, R123 and R134a. The predicted results using new correlations show good agreement with experimental results within an absolute deviation of ±30%. Experimental results for the micro-fin tubes were also compared with previous correlations for micro-fin Tubes.

  2. Visualization of two-phase gas-liquid flow regimes in horizontal and slightly-inclined circular tubes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Livia Alves [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: livia@lasme.coppe.ufrj.br; Cunha Filho, Jurandyr; Su, Jian [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Nuclear Engineering Program], Emails: cunhafilho@lasme.coppe.ufrj.br, sujian@lasme.coppe.ufrj.br; Faccini, Jose Luiz Horacio [Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: faccini@ien.gov.br

    2010-07-01

    In this paper a flow visualization study was performed for two-phase gas-liquid flow in horizontal and slightly inclined tubes. The test section consists of a 2.54 cm inner diameter stainless steel circular tube, followed by a transparent acrylic tube with the same inner diameter. The working fluids were air and water, with liquid superficial velocities ranging from 0:11 to 3:28 m/s and gas superficial velocities ranging from 0:27 to 5:48 m/s. Flow visualization was executed for upward flow at 5 deg and 10 deg and downward flow at 2:5 deg, 5 deg and 10 deg, as well as for horizontal flow. The visualization technique consists of a high-speed digital camera that records images at rates of 125 and 250 frames per second of a concurrent air-water mixture through a transparent part of the tube. From the obtained images, the flow regimes were identified (except for annular flow), observing the effect of inclination angles on flow regime transition boundaries. Finally, the experimental results were compared with empirical and theoretical flow pattern maps available in literature. (author)

  3. Performance assessment of an inline horizontal swirl tube cyclone for gas-liquid separation at high pressure

    Institute of Scientific and Technical Information of China (English)

    Nurhayati Mellon; Azmi M. Shariff

    2011-01-01

    The application of swirl tube cyclone for gas-liquid separation is attractive due to its small size and weight.However,very scarce information on the performance of the swirl tube cyclone especially at high operating pressure emulating actual field condition was published in journals.Performance assessment was usually done at a low operating pressure using either air-water,air-fine particle mixtures or dense gas such as SF6.This paper fills the existing gaps and reports the initial findings on the performance assessment of a horizontal swirl tube cyclone for gas-liquid separation operating at a flow rate of 5 MMSCFD at 40-60 bar operating pressure.

  4. The evaluation of validity of the RELAP5/Mod3 flow regime map for horizontal small diameter tubes at low pressure

    Energy Technology Data Exchange (ETDEWEB)

    Agafonova, N. [St. Petersburg State Technical Univ. (Russian Federation); Banati, J. [Lappeenranta Univ. of Technology (Finland)

    1997-12-31

    RELAP5/MOD3 code was developed for Western type power water reactors with vertical steam generators. Thus, this code should be validated also for WWER design with horizontal steam generators. In application for horizontal steam generators the situation with two-phase flow inside small diameter tubes is possible when the first circuit pressure drops in accident below the pressure level in the boiling water. It is known that computer codes have not always modelled correctly the two-phase flow inside horizontal tubes at low pressures (less than 4-6 MPa). It may be the result of erroneous prediction of the flow regime. Correct prediction of the flow regime is especially important for the fully or partly stratified flow in horizontal tubes. The aim of this study is the attempt of verification of the flow regime map, which is used in the RELAP5/MOD3 computer code for two-phase flow in horizontal small diameter tubes. `Small diameter tube` means according RELAP5/MOD3 that the inner diameter of the tube is less (or equal) than 0.018 m. The inner tube diameter in horizontal steam generators is equal 0.013 m. (orig.). 19 refs.

  5. TURBULENT FILM CONDENSATION OF PURE VAPORS FLOWING NORMAL TO A HORIZONTAL CONDENSER TUBE - CONSTANT HEAT FLUX AT THE TUBE WALL

    Directory of Open Access Journals (Sweden)

    K.V. Sharma

    2011-12-01

    Full Text Available A mathematical model was developed for the study of external turbulent film condensation of pure vapours flowing downward and normal to the axis of the condenser tube with constant heat flux conditions maintained at the tube wall. The magnitude of interfacial shear was estimated for a given external flow condition of the vapour with the help of Colburn’s analogy. The average condensation heat transfer coefficients for different system conditions were evaluated. The present theory was compared with the available experimental and theoretical data in the literature and was found to be satisfactory.

  6. Numerical investigation of forced convection of nano fluid flow in horizontal U-longitudinal finned tube heat exchanger

    Science.gov (United States)

    Qasim, S. M.; Sahar, A. F. A.; Firas, A. A.

    2015-11-01

    A numerical study has been carried out to investigate the heat transfer by laminar forced convection of nanofluid taking Titania (TiO2) and Alumina (Al2O3) as nanoparticles and the water as based fluid in a three dimensional plain and U-longitudinal finned tube heat exchanger. A Solid WORKS PREMIUM 2012 is used to draw the geometries of plain tube heat exchanger or U-longitudinal copper finned tube heat exchanger. Four U-longitudinal copper fins have 100 cm long, 3.8cm height and 1mm thickness are attached to a straight copper tube of 100 cm length, 2.2 cm inner diameter and 2.39 cm outer diameter. The governing equations which used as continuity, momentum and energy equations under assumptions are utilized to predict the flow field, temperature distribution, and heat transfer of the heat exchanger. The finite volume approach is used to obtain all the computational results using commercial ANSYS Fluent copy package 14.0 with assist of solid works and Gambit software program. The effect of various parameters on the performance of heat exchanger are investigated numerically such as Reynolds' number (ranging from 270 to 1900), volume consternation of nanoparticles (0.2%, 0.4%, 0.6%, 0.8%), type of nanoparticles, and mass flow rate of nanofluid in the hot region of heat exchanger. For 0.8% consternation of nanoparticles, heat transfer has significant enhancement in both nanofluids. It can be found about 7.3% for TiO2 and about 7.5% for Al2O3 compared with the water only as a working fluid.

  7. Heat Transfer between Horizontal Finned Tubes and a Gas-Solid Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Grewal, N.S.; Cheung, T.K.; Saxena, S.C.

    1985-04-01

    The heat-transfer coefficients are measured between electrically heated V-thread tubes and square fluidized beds of alumina and silica sand. The effect of particle size, mass fluidizing velocity, V-thread pitch, and tube pitch on the heat transfer rate is investigated. One-dimensional and two-dimensional heat conduction models are developed for determining the temperature distribution in a V-thread fin. The models are used to calculate the corrected heat-transfer coefficients for the finned tubes. A correlation for the fin effectiveness factor is proposed and is found to be reliable to predict its value for finned tubes with geometry and orientation similar to that in the present investigation. The correlation in conjunction with the existing correlatins for the heat-transfer coefficient for smooth tubes is found, in general, to predict the coefficients for finned tubes immersed in a fluidized bed within + or - 25%.

  8. Indirect Measurement of Local Condensing Heat-Transfer Coefficient Around Horizontal Finned Tubes

    Science.gov (United States)

    1987-09-01

    5.9 Effect of Tube Insulation on Sieder -Tate-Type Coefficient (C ) and Modified Coefficient (C.) for All Tubes •t Atmospheric Pressure...specific tube C Sleder-Tate-type coefficient in eqn. (4.2) C Modified Sieder -Tate-type coefficient in eqn. (5.2) D Tube diameter (m) D Equivalent diameter...an outside diameter equal to the fin root diameter). The Inside heat-transfer coefficent is given by a Sieder -Tate-type equation (4.2) and is

  9. Getting it straight : new production-logging tool for horizontal wells presents stiff competition for coiled tubing

    Energy Technology Data Exchange (ETDEWEB)

    Mahony, J.

    2009-05-15

    This article described a production logging system developed by Norway-based Ziebel AS. The new ZipLog production-logging tool for horizontal wells presents competition for coiled tubing. The article noted that the disadvantage of using coiled tubing is its tendency to resume downhole the curve it acquired on the spool, and a tendency to re-coil. Other issues regarding coiled tubing include weight and rigidity. The benefits of using ZipLog can be attributed to its carbon-epoxy construction. In particular, its lightweight, high strength and natural rigidity make the composite a natural for downhole use. The rod will also allow access to certain highly-deviated wells previously thought unloggable. Road-testing of tools were also presented. Differences related to mode of operation between coiled tubing and ZipLog's rod were also outlined. It was concluded that ZipLog could be used in production tubing, casings and in the open hole. Although the rod does not currently include any electrical cable, plans are underway to add one, enabling standard wireline logging to be added to the system's uses. In addition, the article noted that plans to introduce the system in Canada are under consideration. 1 ref., 3 figs.

  10. Pool boiling of water-Al2O3 and water-Cu nanofluids on horizontal smooth tubes

    Science.gov (United States)

    2011-01-01

    Experimental investigation of heat transfer during pool boiling of two nanofluids, i.e., water-Al2O3 and water-Cu has been carried out. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight. The horizontal smooth copper and stainless steel tubes having 10 mm OD and 0.6 mm wall thickness formed test heater. The experiments have been performed to establish the influence of nanofluids concentration as well as tube surface material on heat transfer characteristics at atmospheric pressure. The results indicate that independent of concentration nanoparticle material (Al2O3 and Cu) has almost no influence on heat transfer coefficient while boiling of water-Al2O3 or water-Cu nanofluids on smooth copper tube. It seems that heater material did not affect the boiling heat transfer in 0.1 wt.% water-Cu nanofluid, nevertheless independent of concentration, distinctly higher heat transfer coefficient was recorded for stainless steel tube than for copper tube for the same heat flux density. PMID:21711741

  11. Pool boiling of water-Al2O3 and water-Cu nanofluids on horizontal smooth tubes.

    Science.gov (United States)

    Cieslinski, Janusz T; Kaczmarczyk, Tomasz Z

    2011-03-15

    Experimental investigation of heat transfer during pool boiling of two nanofluids, i.e., water-Al2O3 and water-Cu has been carried out. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight. The horizontal smooth copper and stainless steel tubes having 10 mm OD and 0.6 mm wall thickness formed test heater. The experiments have been performed to establish the influence of nanofluids concentration as well as tube surface material on heat transfer characteristics at atmospheric pressure. The results indicate that independent of concentration nanoparticle material (Al2O3 and Cu) has almost no influence on heat transfer coefficient while boiling of water-Al2O3 or water-Cu nanofluids on smooth copper tube. It seems that heater material did not affect the boiling heat transfer in 0.1 wt.% water-Cu nanofluid, nevertheless independent of concentration, distinctly higher heat transfer coefficient was recorded for stainless steel tube than for copper tube for the same heat flux density.

  12. Boiling heat-transfer coefficient variation for R407C inside horizontal tubes of a refrigerating vapour-compression plant's shell-and-tube evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Torrella, Enrique [Department of Applied Thermodynamics, Camino de Vera, 14, Polytechnic University of Valencia, E-46022 Valencia (Spain); Navarro-Esbri, Joaquin; Cabello, Ramon [Department of Technology, Campus de Riu Sec,University Jaume I, E-12071 Castellon (Spain)

    2006-03-01

    The present paper presents experimental results obtained from a refrigerating vapour-compression plant's shell-and-tube (1-2) evaporator working with R407C. Several tests have been carried out to study the influence of the evaporating pressure and the refrigerant's mass flow rate on the refrigerant's boiling heat-transfer coefficient inside horizontal tubes. This work has been performed by analyzing the variations of the evaporator's overall thermal-resistance, computed using the effectiveness-NTU method, considering the influence of pressure drops and glide at the evaporator, and finally transferring the results and conclusions to the boiling heat-transfer coefficient. It has been observed that the variations of the boiling heat-transfer coefficient show a dependence on the evaporating temperature and the refrigerant's mass-flow rate, which has been analyzed in the test range. [Author].

  13. Characteristics of two-phase flow pattern transitions and pressure drop of five refrigerants in horizontal circular small tubes

    Energy Technology Data Exchange (ETDEWEB)

    Pamitran, A.S. [Department of Mechanical Engineering, University of Indonesia, Kampus Baru UI, Depok 16424 (Indonesia); Choi, Kwang-Il [Graduate School, Chonnam National University, San 96-1, Dunduk-Dong, Yeosu, Chonnam 550-749 (Korea); Oh, Jong-Taek [Department of Refrigeration and Air Conditioning Engineering, Chonnam National University, San 96-1, Dunduk-Dong, Yeosu, Chonnam 550-749 (Korea); Hrnjak, Pega [Department of Mechanical Science and Engineering, ACRC, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801 (United States)

    2010-05-15

    An experimental investigation on the characteristics of two-phase flow pattern transitions and pressure drop of R-22, R-134a, R-410A, R-290 and R-744 in horizontal small stainless steel tubes of 0.5, 1.5 and 3.0 mm inner diameters is presented. Experimental data were obtained over a heat flux range of 5-40 kW/m{sup 2}, mass flux range of 50-600 kg/(m{sup 2} s), saturation temperature range of 0-15 C, and quality up to 1.0. Experimental data were evaluated with Wang et al. and Wojtan et al. [Wang, C.C., Chiang, C.S., Lu, D.C., 1997. Visual observation of two-phase flow pattern of R-22, R-134a, and R-407C in a 6.5-mm smooth tube. Exp. Therm. Fluid Sci. 15, 395-405; Wojtan, L., Ursenbacher, T., Thome, J.R., 2005. Investigation of flow boiling in horizontal tubes: part I - a new diabatic two-phase flow pattern map. Int. J. Heat Mass Transfer 48, 2955-2969.] flow pattern maps. The effects of mass flux, heat flux, saturation temperature and inner tube diameter on the pressure drop of the working refrigerants are reported. The experimental pressure drop was compared with the predictions from some existing correlations. A new two-phase pressure drop model that is based on a superposition model for two-phase flow boiling of refrigerants in small tubes is presented. (author)

  14. Experimental investigation of subcooled flow boiling of water/TiO2 nanofluid in a horizontal tube

    Directory of Open Access Journals (Sweden)

    Rajabnia Hossein

    2016-01-01

    Full Text Available Subcooled flow boiling heat transfer of water/TiO2 nanofluid in a horizontal tube is experimentally investigated. To validate the experimental apparatus as well as the experimental procedure, data for distilled water were compared with the available results on the literature in both single phase and subcooled flow boiling regime. Experimental investigations were carried out at three nanoparticles volumetric concentrations of 0.01%, 0.1%, and 5%. It was found that the nanofluid heat transfer coefficient in single-phase flow regime augments with the nanoparticle concentration. However, in the case of subcooled flow boiling regime the heat transfer coefficient decreases with the nanoparticle volume fractions.

  15. Heat and mass transfer characteristics of absorption of R134a into DMAC in a horizontal tube absorber

    Science.gov (United States)

    Harikrishnan, L.; Maiya, M. P.; Tiwari, S.; Wohlfeil, A.; Ziegler, F.

    2009-10-01

    In this paper the heat and mass transfer characteristics of a horizontal tube absorber for the mixture R134a/DMAC in terms of experimentally gained heat and mass transfer coefficients are presented. The heat transfer coefficient is mainly dependent on the solution’s mass flow rate. The mass transfer coefficient is strongly related to the subcooling of the solution. The data are compared to experimental absorption characteristics of water into aqueous lithium bromide in an absorption chiller. The mass transfer coefficients are of similar size whereas the heat transfer coefficients are about one order of magnitude smaller for R134a-DMAC.

  16. Heat Transfer Coefficient during Evaporation of R-1234yf, R-134a, and R-22 in Horizontal Circular Small Tubes

    Directory of Open Access Journals (Sweden)

    Kwang-Il Choi

    2013-01-01

    Full Text Available Experimental data of heat transfer coefficient during evaporation of R-1234yf, R-134a, and R-22 in horizontal circular small tubes are compared. The local heat transfer coefficient is obtained for heat fluxes ranging from 10 to 35 kW m−2, mass fluxes ranging from 100 to 650 kg m−2 s−1, saturation temperatures of 5, 10, and 15°C, and quality up to 1.0. The test sections are made of stainless steel tubes with inner diameters of 1.5 and 3.0 mm, the lengths of 1000 and 2000. Effects of heat flux, inner tube diameter, and saturation temperature on heat transfer coefficient are reported in the present study. Nucleate boiling heat transfer contribution is predominant, especially at low quality region, and laminar flow appears in the evaporative small tubes. The experimental results are compared against four existing heat transfer coefficients, and the modified correlation of heat transfer coefficient is developed with good prediction.

  17. Heat transfer from a horizontal finned tube bundle in bubbling fluidized beds of small and large particles

    Energy Technology Data Exchange (ETDEWEB)

    Devaru, C.B. [Jayachamaraja College of Engineering, Mysore (India). Dept. of Mechanical Engineering; Kolar, A.K. [Indian Inst. of Technology, Madras (India). Dept. of Mechanical Engineering

    1995-12-31

    Steady state average heat transfer coefficient measurements were made by the local thermal simulation technique in a cold, square, bubbling air-fluidized bed (0.305 m x 0.305 m) with immersed horizontal finned tube bundles (in-line and staggered) with integral 60{degree} V-thread. Studies were conducted using beds of small (average particle diameter less than 1 mm) sand particles and of large (average particle diameter greater thin 1 mm) particles (raagi, mustard, millet and coriander). The fin pitch varied from 0.8 to 5.0 mm and the fin height varied from 0.69 to 4.4 mm. The tube pitch ratios used were 1.75 and 3.5. The influence of bed particle diameter, fluidizing velocity, fin pitch, and tube pitch ratio on average heat transfer coefficient was studied. Fin pitch and bed particle diameter are the most significant parameters affecting heat transfer coefficient within the range of experimental conditions. Bed pressure drop depends only on static bed height. New direct correlations, incorporating easily measurable quantities, for average heat transfer coefficient for finned tube bundles (in-line and staggered) are proposed.

  18. Experimental Study on Cooling Heat Transfer of Supercritical Carbon Dioxide Inside Horizontal Micro-Fin Tubes

    Science.gov (United States)

    Kuwahara, Ken; Higashiiu, Shinya; Ito, Daisuke; Koyama, Shigeru

    This paper deals with the experimental study on cooling heat transfer of supercritical carbon dioxide inside micro-fin tubes. The geometrical parameters in micro-fin tubes used in the present study are 6.02 mm in outer diameter, 4.76 mm to 5.11 mm in average inner diameter, 0.15 mm to 0.24 mm in fin height, 5 to 25 in helix angle, 46 to 52 in number of fins and 1.4 to 2.3 in area expansion ratio. Heat transfer coefficients were measured at 8-10 MPa in pressure, 360-690 kg/(m2•s) in mass velocity and 20-75 °C in CO2 temperature. The measured heat transfer coefficients of micro-fin tubes were 1.4 to 2 times higher than those of the smooth tube having 4.42 in inner diameter. The predicted heat transfer coefficients using the correlation equation, which was developed for single-phase turbulent fluid flow inside micro-fin-tubes, showed large deviations to the measured values. The new correlation to predict cooling heat transfer coefficient of supercritical carbon dioxide inside micro-fin tubes was developed taking into account the shape of fins based on experimental data empirically. This correlation equation agreed within ±20% of almost all of the experimental data.

  19. PARTICULARITIES REGARDING THE OPERATING PROCESS OF THE CUTTING AND EXTRACTION DEVICE IN THE CANDU HORIZONTAL FUEL CHANNELS PRESSURE TUBE DECOMMISSIONING PART II: CUTTING AND EXTRACTING PRESSURE TUBE PROCESS

    Directory of Open Access Journals (Sweden)

    Constantin POPESCU

    2016-05-01

    Full Text Available This paper presents some details of operation process for a Cutting and Extraction Device (CED in order to achieve the decommissioning of the horizontal fuel channels pressure tube in the CANDU 6 nuclear reactor. The most important characteristic of the Cutting and Extraction Device (CED is his capability of totally operator’s protection against the nuclear radiation during pressure tube decommissioning. The cutting and extracting pressure tube processes present few particularities due to special adopted technical solutions: a special module with three cutting rollers (system driven by an actuator, a guiding-extracting and connecting module (three fixing claws which are piloted by an actuator and block the device in the connecting position with extracting plugs. The Cutting and Extraction Device (CED is a train of modules equipped with special systems to be fully automated, connected with a Programmable Logic Controller (PLC and controlled by an operator panel type Human Machine Interface (HMI. All processes are monitored by video cameras. In case of error, the process is automatically stopped, the operator receiving an error message and the last sequence could be reinitialized or aborted due to safety reasons.

  20. Abdominal Plain Film Before Gastrostomy Tube Placement to Predict Success of Percutaneous Endoscopic Procedure

    NARCIS (Netherlands)

    Pruijsen, J. M.; de Bruin, A.; Sekema, G.; Koetse, H. A.; van Rheenen, P. F.

    2013-01-01

    Objectives: Percutaneous endoscopic gastrostomy (PEG) tube feeding is a convenient method for children requiring long-term enteral nutrition. Preoperative fitness of the majority of pediatric PEG candidates is graded as American Society of Anesthesiologists physical status >= III, indicating increas

  1. Counter-current flow in a vertical to horizontal tube with obstructions

    Energy Technology Data Exchange (ETDEWEB)

    Tye, P.; Matuszkiewicz, A.; Teyssedou, A. [Institut de Genie Nucleaire, Quebec (Canada)] [and others

    1995-09-01

    This paper presents experimental results on counter-current flow and flooding in an elbow between a vertical and a horizontal run. The experimental technique used allowed not only the flooding limit to be determined, but also the entire partial delivery region to be studied as well. The influence that various size orifices placed in the horizontal run have on both the delivered liquid flow rates and on the flooding limits is also examined. It is observed that both the flooding limits and the delivered liquid flow rates decrease with decreasing orifice size. Further, it is also observed that the mechanisms that govern the partial delivery of the liquid are significantly different when an orifice is present in the horizontal leg as compared to the case when no orifice is present.

  2. An Experimental Study of Filmwise Condensation on Horizontal Enhanced Condenser Tubing.

    Science.gov (United States)

    1979-12-01

    46 4. Sieder -Tate Parameters --------------------------- 46 5. Friction Factor ---------------------------------- 47 6. Tube...Representation Of Procedure Used To Find Un ---104 13. Schematic Representation Of Procedure Used To Find Sieder -Tate Parameter --------------------- 105...14. Schematic Representation Of Procedure Used To Find Sieder -Tate Constant (Ci), hi and ho -------------------- 106 15. Cross Sectional View Of

  3. Mixed convection laminar flow and heat transfer of liquids in horizontal internally finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Shome, B. [Univ. of Delaware, Newark, DE (United States). Dept. of Mechanical Engineering

    1998-01-01

    Energy and material savings, as well as economic incentives, have led to concentrated efforts over the past several decades in the field of heat transfer enhancement to produce more efficient and compact heat exchangers. Internally finned tubes are widely used for heat transfer enhancement, particularly in chemical process and petroleum industries. A finned tube heat exchanger with optimum geometry could offer 35--40% increase in heat duty for equal pumping power and size over a smooth tube heat exchanger or a comparable decrease in the heat exchanger size for a given heat duty. Developing mixed convection flow in internally finned tubes with variable viscosity was numerically investigated for a fin geometry range of 8 {le} N {le} 24, 0.1 {le} H {le} 0.3 and an operating condition range of 50 {le} Pr{sub in} {le} 1,250, 0 {le} Ra{sub in} {le} 10{sup 7}, and 0 {le} q{sub w}d/k{sub in} {le} 2,000. The numerical model was validated by comparison with existing numerical and experimental data. Internal finning was found to produce a complex two-cell, buoyancy-induced vortex structure. The results show that coring (retarded velocity in the interfin region) leads to poor heat transfer performance of tubes with large numbers of fins or with tall fins. The overall results indicated that large enhancement in the heat transfer can be obtained in the entrance region. Furthermore, variable viscosity effects are seen to have a pronounced effect on the friction factor and Nusselt number predictions.

  4. Correlations of Two-phase Friction of Refrigerant in Horizontal Smooth Tube with 2.5 mm inside Diameter

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Two-phase flow pressure drop measurements are made during phase change heat transfer process of R-22 in small horizontal smooth tubes with 2. 5 mm inside diameter.Conclusions are drawn that the quality corresponding to pressure gradient peak value of small tubes became higher than that of large tubes and that effects of quality on pressure drop become weak as the increase of mass flux.The experiment data are compared with predicted values of the state-of-the-art correlations from the open literature,which indicates that most of the state-of-the-art correlations fail to predict the present experimental data. Chisholm model shows a relatively better predictive ability than the other empirical correlations because it has the lowest mean deviation of 26.7%. But the predicted values of Chisholm model are 50% lower than experimental data when quality becomes higher. In this regard, an new empirical correlation based on Chisholm model is developed and this modified Chisholm correlation can describe 95% of the present data with ± 20% mean deviations.

  5. An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

    Directory of Open Access Journals (Sweden)

    Vinš Václav

    2015-01-01

    Full Text Available New experimental apparatus for measurement of the surface tension of liquids under the metastable supercooled state has been designed and assembled in the study. The measuring technique is similar to the method employed by P.T. Hacker [NACA TN 2510] in 1951. A short liquid thread of the liquid sample was sucked inside a horizontal capillary tube partly placed in a temperature-controlled glass chamber. One end of the capillary tube was connected to a setup with inert gas which allowed for precise tuning of the gas overpressure in order of hundreds of Pa. The open end of the capillary tube was precisely grinded and polished before the measurement in order to assure planarity and perpendicularity of the outer surface. The liquid meniscus at the open end was illuminated by a laser beam and observed by a digital camera. Application of an increasing overpressure of the inert gas at the inner meniscus of the liquid thread caused variation of the outer meniscus such that it gradually changed from concave to flat and subsequently convex shape. The surface tension at the temperature of the inner meniscus could be evaluated from the overpressure corresponding to exactly planar outer meniscus. Detailed description of the new setup together with results of the preliminary tests is provided in the study.

  6. Measurement and analysis of the re-wetting front velocity during quench cooling of hot horizontal tubes

    Energy Technology Data Exchange (ETDEWEB)

    Takrouri, Kifah, E-mail: takroukj@mcmaster.ca [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Luxat, John, E-mail: luxatj@mcmaster.ca [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Hamed, Mohamed [Thermal Processing Laboratory (TPL), Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada)

    2017-01-15

    Highlights: • Two phase flow & re-wetting front velocity were studied for quench of hot tubes. • The velocity decreased as temperature difference between tube and coolant decreased. • Increasing surface curvature was found to decrease the re-wetting front velocity. • Increasing tube thermal conductivity decreased the velocity. • Correlations were developed to predict the front velocity. - Abstract: When a liquid is put into contact with a hot dry surface, there exists a maximum temperature called the re-wetting temperature below which the liquid is in actual contact with the surface. Re-wetting occurs after destabilization of a vapor film that exists between the hot surface and the liquid. If re-wetting is established at a location on the hot surface, a wet patch appears at that location and starts to spread to cover and cool the entire surface. The outer edge of the wet patch is called the re-wetting front and can proceed only if the surface ahead of it cools down to the re-wetting temperature. Study of re-wetting heat transfer is very important in nuclear reactor safety for limiting the extent of core damage during the early stages of severe accidents after loss of coolant accidents LOCA and is essential for predicting the rate at which the coolant cools an overheated core. One of the important parameters in re-wetting cooling is the velocity at which the re-wetting front moves on the surface. In this study, experimental tests were carried out to investigate the re-wetting front velocity on hot horizontal cylindrical tubes being cooled by a vertical rectangular water multi-jet system. Effects of initial surface temperature in the range 400–740 °C, water subcooling in the range 15–80 °C and jet velocity in the range 0.17–1.43 m/s on the re-wetting front velocity were investigated. The two-phase flow behavior was observed by using a high-speed camera. The re-wetting front velocity was found to increase by increasing water subcooling, decreasing

  7. Experimental investigation on condensation heat transfer of R134a on single horizontal copper and stainless steel three-dimensional finned tubes

    Science.gov (United States)

    Qin, Peng; Zhang, Zhengguo; Xu, Tao; Gao, Xuenong; Wang, Shuangfeng

    2013-07-01

    Condensation heat transfer characteristics of R134a on the horizontal copper and stainless steel three-dimensional (3D) finned tubes are experimentally investigated. The objective is to obtain the basic data for film condensation of R134a on low and high thermal conductivity 3D enhanced tubes. Experiments were carried out at saturation temperatures of 39 °C and wall subcoolings from 3.2 to 10.5 °C. The results show that the condensation heat transfer coefficients on the smooth copper and stainless steel tubes are smaller than those predicted by the Nusselt analysis by 4.4% and 4.8%, respectively. The average enhancement factors provided by the copper and stainless steel 3D finned tubes are 7.86 and 3.34, respectively. The copper 3D finned tube has higher enhancement factor than that of the stainless steel 3D finned tube, due to its high fin and thermal conductivity.

  8. Two-phase heat transfer and pressure drop of LNG during saturated flow boiling in a horizontal tube

    Science.gov (United States)

    Chen, Dongsheng; Shi, Yumei

    2013-12-01

    Two-phase heat transfer and pressure drop of LNG (liquefied natural gas) have been measured in a horizontal smooth tube with an inner diameter of 8 mm. The experiments were conducted at inlet pressures from 0.3 to 0.7 MPa with a heat flux of 8-36 kW m-2, and mass flux of 49.2-201.8 kg m-2 s-1. The effect of vapor quality, inlet pressure, heat flux and mass flux on the heat transfer characteristic are discussed. The comparisons of the experimental data with the predicted value by existing correlations are analyzed. Zou et al. (2010) correlation shows the best accuracy with 24.1% RMS deviation among them. Moreover four frictional pressure drop methods are also chosen to compare with the experimental database.

  9. Saturated flow boiling heat transfer correlation for carbon dioxide for horizontal smooth tubes

    Science.gov (United States)

    Turgut, Oguz Emrah; Asker, Mustafa

    2017-01-01

    Literature comprises fewer studies about flow boiling modelling of refrigerants for in tube flows. In addition, researches on two phase flow heat transfer are based on the mathematical models which were derived in a very limited operational condition and correlated for their own measurements. In this study, a new flow boiling model including the superposed effects of nucleate and convective boiling mechanisms is proposed through the minimization of the cumulative error between the proposed mathematical model and actual data by means of artificial cooperative search algorithm and applied to the database of R-744 (carbon dioxide), available from different studies in the literature. Predictions obtained from the proposed model have been compared with those of retained from the literature correlations developed for flow boiling in tubes. The comparison results indicate that the new model outperforms the literature correlations in terms of prediction accuracy. Results of the comparisons reveal that the proposed flow boiling mathematical model has a mean absolute relative error of 14.6% and predicts 76.7% of the experimental data within ±20.0%.

  10. Indoor Solar Thermal Energy Saving Time with Phase Change Material in a Horizontal Shell and Finned-Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    S. Paria

    2015-01-01

    Full Text Available An experimental as well as numerical investigation was conducted on the melting/solidification processes of a stationary phase change material (PCM in a shell around a finned-tube heat exchanger system. The PCM was stored in the horizontal annular space between a shell and finned-tube where distilled water was employed as the heat transfer fluid (HTF. The focus of this study was on the behavior of PCM for storage (charging or melting and removal (discharging or solidification, as well as the effect of flow rate on the charged and discharged solar thermal energy. The impact of the Reynolds number was determined and the results were compared with each other to reveal the changes in amount of stored thermal energy with the variation of heat transfer fluid flow rates. The results showed that, by increasing the Reynolds number from 1000 to 2000, the total melting time decreases by 58%. The process of solidification also will speed up with increasing Reynolds number in the discharging process. The results also indicated that the fluctuation of gradient temperature decreased and became smooth with increasing Reynolds number. As a result, by increasing the Reynolds number in the charging process, the theoretical efficiency rises.

  11. Indoor solar thermal energy saving time with phase change material in a horizontal shell and finned-tube heat exchanger.

    Science.gov (United States)

    Paria, S; Sarhan, A A D; Goodarzi, M S; Baradaran, S; Rahmanian, B; Yarmand, H; Alavi, M A; Kazi, S N; Metselaar, H S C

    2015-01-01

    An experimental as well as numerical investigation was conducted on the melting/solidification processes of a stationary phase change material (PCM) in a shell around a finned-tube heat exchanger system. The PCM was stored in the horizontal annular space between a shell and finned-tube where distilled water was employed as the heat transfer fluid (HTF). The focus of this study was on the behavior of PCM for storage (charging or melting) and removal (discharging or solidification), as well as the effect of flow rate on the charged and discharged solar thermal energy. The impact of the Reynolds number was determined and the results were compared with each other to reveal the changes in amount of stored thermal energy with the variation of heat transfer fluid flow rates. The results showed that, by increasing the Reynolds number from 1000 to 2000, the total melting time decreases by 58%. The process of solidification also will speed up with increasing Reynolds number in the discharging process. The results also indicated that the fluctuation of gradient temperature decreased and became smooth with increasing Reynolds number. As a result, by increasing the Reynolds number in the charging process, the theoretical efficiency rises.

  12. Flow and heat transfer characteristics of graphene oxide nanofluids in a horizontal tube

    Science.gov (United States)

    Nunna, Maheshwar Rao

    This thesis presents a fundamental study conducted on heat transfer and decrease in flow through a straight copper tube of a graphene oxide (GO) nanofluid developed in-house. The GO particles were synthesized using the modified Hummers method. The physicochemical properties of the fabricated GO were characterized using X-ray diffraction analysis (XRD), a scanning electron microscope (SEM), and UV-Vis spectrophotometry, and the particle size distribution was investigated using dynamic light scattering. GO nanofluids of 0.01 wt. % and 0.1 wt. % were prepared by dispersing GO sheets in de-ionized water. Thermo-physical properties of GO nanofluids were also measured at different temperatures. An experimental setup was developed to find the heat transfer characteristics and pressure drop of nanofluids in the test section. A flexible heater was used to provide the constant heat flux condition at the wall of the tube for all the experiments. In this study, the experimental investigations of flow regime, flowrates, pressure drop and heat transfer characteristics were performed by considering three different heat flux conditions (7.38 kW/m2, 9.08 kW/m2, and 12.55 kW/m2) at three different set points of variable frequency drive (VFD), 15, 20, and 25, connected to the pump. Due to the increase in viscosity, there was a decrease in flowrate and Reynolds number from 0.01 wt. % to 0.1 wt. % of GO nanofluids at constant pump frequency. Experimental data obtained for water was validated with available data from the literature, and the correlations were formulated for the Nusselt number and Reynolds number by considering the multiple regression analysis. Convective heat transfer coefficient and dimensionless wall temperature for water and GO nanofluids were investigated. A rise in dimensionless wall temperature with the increase of velocity and particle concentration was observed. The convective heat transfer coefficient for GO 0.01 wt. % was higher when compared to GO 0.1 wt

  13. Thermal-hydraulic behavior of Sc-C02 in a horizontal circular straight tube

    Science.gov (United States)

    Tanimizu, Katsuyoshi; Sadr, Reza; Ranjan, Davesh

    2011-11-01

    Fluids above critical pressure have been practically utilized for 60 years in many applications and their use and interest is still increasing in many areas, especially power generation industries and chemical industries. Above critical pressure, very rapid changes in thermophysical properties take place near the pseudocritical temperature. In this region, the fluid transforms from liquid-like to gas-like behavior when the fluid temperature rises up and passes through the pseudocritical temperature. This allows enormous potential for energy transfer, but also alters the turbulent flow due to changes in the turbulent shear stress brought about by acceleration and buoyancy effects. However, we have not fully understood their dynamic behaviors such as turbulence yet. A supercritical CO2 testing loop has been built at Texas A&M University at Qatar to perform heat transfer and pressure drop measurements and investigate the thermo-physical and dynamic characteristics of supercritical carbon dioxide flow. The results of heat transfer measurements in a super critical fluid conducted in a horizontal pipe are reported and discussed here. Supported by QNRF.

  14. The effect of magnetic field on nanofluids heat transfer through a uniformly heated horizontal tube

    Science.gov (United States)

    Hatami, N.; Kazemnejad Banari, A.; Malekzadeh, A.; Pouranfard, A. R.

    2017-02-01

    In this study, the effects of magnetic field on forced convection heat transfer of Fe3O4-water nanofluid with laminar flow regime in a horizontal pipe under constant heat flux conditions were studied, experimentally. The convective heat transfer of magnetic fluid flow inside the heated pipe with uniform magnetic field was measured. Fe3O4 nanoparticles with diameters less than 100 nm dispersed in water with various volume concentrations are used as the test fluid. The effect of the external magnetic field (Ha = 33.4 ×10-4 to 136.6 ×10-4) and nanoparticle concentrations (φ = 0, 0.1, 0.5, 1%) on heat transfer characteristics were investigated. Results showed that by the presence of a magnetic field, increase in nanoparticle concentration caused reduction of convection heat transfer coefficient. In this condition, heat transfer decreased up to 25%. Where, in the absence of an external magnetic field, adding magnetic nanoparticles increased convection heat transfer more than 60%. It was observed that the Nusselt number decreased by increasing the Hartmann number at a specified concentration of magnetic nanofluids, that reduction about 25% in heat transfer rate could be found.

  15. Effect of Fin Geometry on Condensation of Zeotropic Refrigerant Mixture R407C in a Staggered Bundle of Horizontal Finned Tubes

    Science.gov (United States)

    Honda, Hiroshi; Takata, Nobuo; Takamatsu, Hiroshi; Kim, Jeongsik; Usami, Keiichiro

    Row-by-row heat transfer data were obtained during condensation of downward-flowing refrigerant mixture R407C in a staggered bundle of horizontal finned tubes. Two kinds of conventional low-fin tubes with flat-sided annular fins and three kinds of three-dimensional fin tubes were tested. The refrigerant mass velocity ranged from 4 to 23 kg/m2s, and the condensation temperature difference from 1.5 to 12 K. At a low to medium film Reynolds number(2000), on the other hand, the highest performance was obtained by one of the low-fin tubes. For all tubes tested, the heat transfer coefficient decreased with decreasing mass velocity. On the basis of previous results for R134a, consideration was given to the characteristics of vapor phase mass transfer of R407C.

  16. Effect of different magnetic field distributions on laminar ferroconvection heat transfer in horizontal tube

    Energy Technology Data Exchange (ETDEWEB)

    Sheikhnejad, Yahya; Hosseini, Reza, E-mail: hoseinir@aut.ac.ir; Saffar-avval, Majid

    2015-09-01

    The forced convection heat transfer of ferrofluid steady state laminar flow through a circular axisymmetric horizontal pipe under different magnetic field is the focus of this study. The pipe is under constant heat flux while different linear axial magnetic fields were applied on the ferrofluid with equal magnetic energy. In this scenario, viscosity of ferrofluid is temperature dependent, to capture ferrofluid real behavior a nonlinear Langevin equation was considered for equilibrium magnetization. For this purpose, the set of nonlinear governing PDEs was solved using proper CFD techniques: the finite volume method and SIMPLE algorithm were used to discretize and numerically solve the governing equation in order to obtain thermohydrodynamic flow characteristics. The numerical results show a promising enhancement of up to 135.7% in heat transfer as a consequence of the application of magnetic field. The magnetic field also increases pressure loss of up to 77% along the pipe; but effectiveness (favorable to unfavorable effect ratio) of the magnetic field as a performance index economically justifies its application such that higher magnetic field intensity causes higher effectiveness of up to 1.364. - Highlights: • In this numerical study, the thermohydrodynamic characteristics of a laminar steady state ferroconvection was investigated in circular axisymmetric pipe under constant heat flux. • A magnetic field causes an increase in both pressure loss and heat transfer such that performance index remain acceptable for all linear distributions. • In constant total magnetic energy, an increase of magnetic field gradient tends to decrease the effectiveness slightly. • Magnetic field of lower gradient with high intensity is the best choice for both saving energy and heat transfer enhancement increase of up to 1.3638 and 135.65% respectively.

  17. Multi-objective optimization of a plain fin-and-tube heat exchanger using genetic algorithm

    Science.gov (United States)

    Juan, Du; Qin, Qian Zuo

    2014-04-01

    In the present paper, a plate fin-and-tube heat exchanger (PFTHE) is considered for optimization with air and water as working fluid, four geometric variables are taken as parameters for optimization, a Genetic Algorithm (GA) was used to search for the optimal structure sizes of the PFTHE, the maximum total heat transfer rate and the minimum total pressure drop are taken as objective functions in GA, respectively. Performance of the optimized result was evaluated and correspondingly the total heat transfer rate, the total pressure drop, the heat transfer coefficient and the local Nusselt number, j-factor and friction factor ξ are calculated respectively. Results show that the total heat transfer rate of the optimized heat exchanger increased by about 2.1-9.2% comparing with the original one, the heat transfer coefficient increased by about 8.2-14.7% and the total pressure drop decreased by about 4.4-8% in the range of Re = 1200-14000.

  18. Bubble-assisted film evaporation correlation for saline water at sub-atmospheric pressures in horizontal-tube evaporator

    KAUST Repository

    Shahzad, Muhammad Wakil

    2013-01-01

    In falling film evaporators, the overall heat transfer coefficient is controlled by film thickness, velocity, liquid properties and the temperature differential across the film layer. This article presents the heat transfer behavior for evaporative film boiling on horizontal tubes, but working at low pressures of 0.93-3.60 kPa (corresponding solution saturation temperatures of 279-300 K) as well as seawater salinity of 15,000 to 90,000 mg/l or ppm. Owing to a dearth of literature on film-boiling at these conditions, the article is motivated by the importance of evaporative film boiling in the desalination processes such as the multi-effect distillation (MED) or multi-stage flashing (MSF): It is observed that in addition to the above-mentioned parameters, evaporative heat transfer of seawater is affected by the emergence of micro-bubbles within the thin film layer, particularly when the liquid saturation temperatures drop below 298 K (3.1 kPa). Such micro bubbles are generated near to the tube wall surfaces and they enhanced the heat transfer by two or more folds when compared with the predictions of conventional evaporative film boiling. The appearance of micro-bubbles is attributed to the rapid increase in the specific volume of vapor, i.e., dv/dT, at low saturation temperature conditions. A new correlation is thus proposed in this article and it shows good agreement to the measured data with an experimental uncertainty of 8% and regression RMSE of 3.5%. © 2012 Elsevier Ltd. All rights reserved.

  19. Experimental and numerical investigation of the cylindrical blade tube inserts effect on the heat transfer enhancement in the horizontal pipe exchangers

    Science.gov (United States)

    Karagoz, Sendogan; Afshari, Faraz; Yildirim, Orhan; Comakli, Omer

    2017-09-01

    In this experimental and numerical study an attempt to enhance the heat transfer rate by cylindrical blade that form turbulence flow inside the exchanger pipe is carried out. The effects of the blade geometry are also examined to investigate heat transfer rate in experimented tube inserts. Experiments are performed in different blade spacing (Sy1,2,3 = 101-216-340 mm) and various blade angles (α1,2,3 = 0°-45°-90°). The water flow rate inside the tube is adjusted in three different ranges to approach intended Reynolds numbers (Re1,2,3 = 6000-11,000-17,000). Nusselt number, Reynolds number and effect of friction factor are investigated separately. For all experiments, the increase in Nu number due to used tube inserts is recorded and compared to each other and plain tube in the related profiles. It is concluded that installed tube inserts in the heat exchanger tube, led to a significant increase in Nu number and energy saving. Among different experimented cases, using mean value in various Re numbers, the highest Nusselt number was obtained at Sy1 = 101 mm which was 24% more than that of plain tube. This value was 18.7 and 8.3% for Sy2 = 216 and Sy3 = 340 mm respectively. By this way, according results for friction factor were 0.30, 0.19 and 0.14. The presented study has been simulated by ANSYS Fluent 16 software to analyze flow behavior and heat transfer characteristics.

  20. Experimental investigation on TBAB clathrate hydrate slurry flows in a horizontal tube: Forced convective heat transfer behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Wenji, Song [Guangzhou Institute of Energy Conversion, CAS, No. 2 Nengyuan Road, Tianhe District, Guangzhou 510640 (China); Key Laboratory of Renewable Energy and Gas Hydrate, CAS, No. 2 Nengyuan Road, Tianhe District, Guangzhou 510640 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Rui, Xiao; Chong, Huang; Shihui, He; Kaijun, Dong; Ziping, Feng [Guangzhou Institute of Energy Conversion, CAS, No. 2 Nengyuan Road, Tianhe District, Guangzhou 510640 (China); Key Laboratory of Renewable Energy and Gas Hydrate, CAS, No. 2 Nengyuan Road, Tianhe District, Guangzhou 510640 (China)

    2009-11-15

    Tetra-n-butyl-ammonium bromide (TBAB) clathrate hydrate slurry (CHS) is one kind of secondary refrigerants, which is promising to be applied into air-conditioning or latent-heat transportation systems as a thermal storage or cold carrying medium for energy saving. It is a solid-liquid two phase mixture which is easy to produce and has high latent heat and good fluidity. In this paper, the heat transfer characteristics of TBAB slurry were investigated in a horizontal stainless steel tube under different solid mass fractions and flow velocities with constant heat flux. One velocity region of weakened heat transfer was found. Moreover, TBAB CHS was treated as a kind of Bingham fluids, and the influences of the solid particles, flow velocity and types of flow on the forced convective heat transfer coefficients of TBAB CHS were investigated. At last, criterial correlations of Nusselt number for laminar and turbulent flows in the form of power function were summarized, and the error with experimental results was within {+-}20%. (author)

  1. Measurement and correlation of frictional pressure drop of refrigerant-based nanofluid flow boiling inside a horizontal smooth tube

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Hao; Ding, Guoliang; Jiang, Weiting; Hu, Haitao [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, 381 Huaihaizhong Road, Shanghai 200020 (China)

    2009-11-15

    The objective of this paper is to investigate the effect of nanoparticle on the frictional pressure drop characteristics of refrigerant-based nanofluid flow boiling inside a horizontal smooth tube, and to present a correlation for predicting the frictional pressure drop of refrigerant-based nanofluid. R113 refrigerant and CuO nanoparticle were used for preparing refrigerant-based nanofluid. Experimental conditions include mass fluxes from 100 to 200 kg m{sup -2} s{sup -1}, heat fluxes from 3.08 to 6.16 kW m{sup -2}, inlet vapor qualities from 0.2 to 0.7, and mass fractions of nanoparticles from 0 to 0.5 wt%. The experimental results show that the frictional pressured drop of refrigerant-based nanofluid increases with the increase of the mass fraction of nanoparticles, and the maximum enhancement of frictional pressure drop is 20.8% under above conditions. A frictional pressure drop correlation for refrigerant-based nanofluid is proposed, and the predictions agree with 92% of the experimental data within the deviation of {+-}15%. (author)

  2. An instrument for local radiative heat transfer measurement around a horizontal tube immersed in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Alavizedeh, N.; Adams, R.L.; Welty, J.R.; Goshayeshi, A. (Oregon State Univ., Corvallis (United States))

    1990-05-01

    An instrument for the measurement of the radiative component of total heat transfer in a high-temperature gas fluidized bed is described. The main objective of this paper is to emphasize the design, instrumentation, and calibration of this device. The results are presented and discussed elsewhere (Alavizadeh, 1985; Alavizadeh et al., 1985). The design makes use of a silicon window to transmit the radiative heat flux to a thermopile-type heat flow detector located at the base of a cavity. The window material thermal conductivity is sufficiently large to prevent conduction errors due to the convective component of total heat transfer. Also, its transmission and mechanical hardness are well suited for the fluid bed environment. The device has been calibrated using a blackbody source both before and after exposure to a fluidized bed, indicating the effect of the abrasive bed environment on performance. The instrument has been used to measure local radiative heat transfer around a horizontal tube. Typical results for a particle size of 2.14 mm and a bed tempeature of 1,050 K are presented and discussed to illustrate instrument performance.

  3. Dynamic Force Reduction and Heat Transfer Improvement for Horizontal Tubes in Large-Particle Gas-Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    Yusumi Nagahashi; John R.Grace; Kok-Seng Lim; Yutaka Asako

    2008-01-01

    The effects of tube bank configuration on forces and heat transfer were investigated for both two-dimensional and three-dimensional gas fluidized beds. Effective dynamic forces and heat transfer coefficients were measured for several tube bank configurations, and it was found that the average forces ate smaller than for a single tube. The heat transfer coefficient can be increased by providing sufficient space for particles to descend around both sides of the tube bank. The results provide useful guidelines for optimizing the configuration of tube banks to achieve high heat transfer coefficients while reducing tube erosion due to dynamic forces.

  4. Study of two-phase flow regime identification in horizontal tube bundles under vertical upward cross-flow condition using wavelet transform

    Institute of Scientific and Technical Information of China (English)

    Xinghua HUANG; Li WANG; Feng JIA

    2008-01-01

    A wavelet-transform based approach for flow regime identification in horizontal tube bundles under vertical upward cross-flow condition was presented. Tests on two-phase flow pattern of R 134a were conducted under low mass velocity and flow boiling conditions over Time series of differential pressure fluctuations were mea-sured and analyzed with discrete wavelet transform. Different time-scale characteristics in bubbly flow, churn flow and annular flow were analyzed. The wavelet energy distributions over scales were found to be appropriate for flow regime identification. Based on the wavelet energy distribution over characteristic scales, a criterion of flow regime identification was proposed. The comparison with experiment results show that it is feasible to use the dis-crete wavelet transform as the tool of flow regime iden-tification in horizontal tube bundles under vertical upward cross-flow condition.

  5. Effect of fin geometry on condensation of downward-flowing R123/R134a in a staggered bundle of horizontal low-finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takata, N. [Kyushu Univ., Institute of Advanced Material Study, Fukuoka (Japan)

    1999-07-01

    Experiments were conducted to obtain row-by-row heat and mass transfer data during condensation of downward-flowing zeotropic mixture R123/R134a in a staggered bundle of horizontal low-finned tubes. The vapor temperature and the mass fraction of R134a at the tube bundle inlet were about 50 deg C and 14%, respectively. The refrigerant mass velocity ranged from 9 to 33 kg/m{sup 2}s, and the condensation temperature difference from 2 to 10 K. Four kinds of low-finned tubes with different fin geometry were tested. The highest heat transfer coefficient was obtained with a tube which showed the highest performance for R123. However, the difference among the tubes was much smaller for the mixture than for R123. The heat transfer coefficient and the vapor-phase mass transfer coefficient decreased significantly with decreasing mass velocity. The mass transfer coefficient increased will condensation temperature difference, which was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient was developed for each tube. (authors)

  6. Experimental measurements for condensation of downward-flowing R123/R134a in a staggered bundle of horizontal low-finned tubes with four fin geometries

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takata, N. [Kyushu Univ., Kasuga, Fukuoka (Japan). Inst. of Advanced Material Study

    1999-07-01

    Experiments were conducted to obtain row-by-row heat and mass transfer data during condensation of downward-flowing zeotropic mixture R123/Rl34a in a staggered bundle of horizontal low-finned tubes. The vapor temperature and the mass fraction of R134a at the tube bundle inlet were about 50{sup o}C and 14%, respectively. The refrigerant mass velocity ranged from 9 to 34 kg m{sup -2} s{sup -1}, and the condensation temperature difference from 1.9 to 12 K. Four kinds of low-finned tubes with different fin geometry were tested. The highest heat transfer coefficient was obtained with a tube which showed the highest performance for R123. However, the difference among the tubes was much smaller for the mixture than for R123. The heat transfer coefficient and the vapor-phase mass transfer coefficient decreased significantly with decreasing mass velocity. The mass transfer coefficient increased with condensation temperature difference, which was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient was developed for each tube. (author)

  7. Film-wise condensation of R134a and R23/R134a mixture on horizontal finned tubes, influence of fin spacing

    Energy Technology Data Exchange (ETDEWEB)

    Belghazi, M.; Signe, J.C.; Marvillet, Ch. [CEA/Grenoble, Dept. de Thermohydraulique et de Physique (DTP-GRETh), 38 (France); Bontemps, A. [Universite Joseph-Fourier, Institut Universitaire de Technologie 1Grenoble I, 38 (France)

    1999-07-01

    The condensation of a pure fluid (R123a) and of a zeotropic mixture (R134a/R123) outside an horizontal bundle of finned tubes have been studied to understand the behaviour of the new refrigerants. Experimental results with pure R134a and several compositions of mixture R134a/R123 have been obtained during condensation on a bundle equipped with finned tubes of three different types: K26 (1024-fpm), K19(748-fpm), K11(433-fpm). The experimental data show the important effect of fin spacing and the different tubes has been made. The experimental data have also been compared to values calculated with the classical Bell and Ghaly model and a good agreement has been noticed. (authors)

  8. Experimental study and modelling of heat transfer during condensation of pure fluid and binary mixture on a bundle of horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Belghazi, M.; Marvillet, C. [Commissariat a l' Energie Atomique, Grenoble (France). Groupement pour la Recherche sur les Echangeurs thermiques; Bontemps, A. [Universite Joseph Fourier, Grenoble (France). LEGI/GRETh

    2003-03-01

    An experimental investigation was conducted to measure the local heat transfer coefficient for each row in a trapezoidal finned horizontal tube bundle during condensation of both pure fluid (HFC 134a) and several compositions of the non-azeotropic binary mixture HFC 23/HFC 134a. The test section is a 13x3 (rows x columns) tube bundle and the heat transfer coefficient is measured using the modified Wilson plot method. The inlet vapour temperature is fixed at 40{sup o}C and the water flow rate in each active row ranges from 170 to 600 l/h. The test series cover five different finned tubes all commercially available, K11 (11 fins/inch), K19 (19 fins/inch), K26 (26 fins/inch), K32 (32 fins/inch), K40 (40 fins/inch) and their performances were compared. The experimental results were checked against available models predicting the heat transfer coefficient during condensation of pure fluids on banks of finned tubes. Modelling of heat exchange during condensation of binary mixtures on bundles of finned tubes based on the curve condensation model is presented. (author)

  9. Condensation of Downward-Flowing Zeotropic Mixture HCFC-123/HFC-134a on a Staggered Bundle of Horizontal Low-Finned Tubes

    Science.gov (United States)

    Honda, Hiroshi; Takamatsu, Hiroshi; Takata, Nobuo

    Expenmentswere conducted to obtain row-by-row heat transfer data during condensation of downward-flowing zeotropic refrigerant mixture HCFC-123/HFC-134 a on a staggered bundle of horizontal low-finned tubes. The vapor temperature and the HFC-134a m ass fraction at the tube bundle inlet were maintained at about 50°C and 14% respectively. The refrigerant mass velocity ranged from 9 to 33 kg/m2s, and the condensation temperature difference from 2 to 12K. Four kinds of low-finned tubes with different fin geometry were tested. The highest heat transfer coefficient was obtained with a tube which showed the highest performance for HCFC-123. However, the effect of fin geometry was much smaller for the mixture than for HCFC-123. The heat transfer coefficient and the vapor-phase mass transfer coefficient decreased significantly with decreasing mass velocity. On the other hand, the mass transfer coefficient increased with condensation temperature difference. This was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient was developed for each tube.

  10. Heat transfer and pressure drop comparison of louver- and plain-finned heat exchangers where one fluid passes through flattened tubes

    Directory of Open Access Journals (Sweden)

    J.M. Gorman

    2015-03-01

    Full Text Available Louvered fins constitute a major methodology for heat transfer enhancement. Of critical significance in evaluating the worthiness of such fins is the comparison between the heat transfer and pressure drop for a thus-finned heat exchanger with the baseline case of a counterpart plain-finned heat exchanger. Up to the present, it appears that such comparisons are confined to heat exchangers in which one of the participating fluids passes through circular tubes. In another basic geometry in which louvered fins have been employed, the aforementioned participating fluid passes through flattened tubes which are virtually rectangular in cross section. The focus of the present paper is to obtain results for the latter basic geometry for both louver-fin-based heat exchangers and counterpart plain-fin-based heat exchangers. The results were obtained by means of numerical simulation over a range of Reynolds numbers spanning approximately a factor of five. Over this range, enhancements of the heat transfer rate ranged from factors of approximately 2.2–2.8. Over this same Reynolds number range, the pressure drop increased by factors of 2.3–3.6. This outcome is attributable to the fact that the rate of heat transfer is less sensitive to the velocity than is the pressure drop.

  11. Horizontal Spatial Variation of Soil Arsenic in Northern Songnen Plain%松嫩平原北部土壤砷水平分异特征分析

    Institute of Scientific and Technical Information of China (English)

    张慧; 付强; 林佳

    2012-01-01

    An experiment was conducted to study the spatial variation characteristics of arsenic contents in surface and deep soil as well as their influencing factors. Samples from surface and deep soil were collected in the northern Songnen plain. The spatial variation characteristics of soil arsenic were quantified based on geostatistic, and the horizontal spatial distribution of arsenic content in surface and deep soil were simulated using the Kriging interpolation in ArcCIS. Results show that arsenic contents in surface and deep soil are lower than the background value of soil arsenic in China, and the study area belongs to a clean and healthy area with low content of soil arsenic. The spatial variation of arsenic in deep soil is relatively more intensive than that of arsenic in deep soil. The spatial patterns of arsenic contents in surface and deep soil exhibit that the soil arsenic content is higher in high-lying Songnen plain and lower in low-lying Songnen plain. Natural factors play a dominant role in the spatial pattern of arsenic contents in surface and deep soil, and human interferences exert an effect, to some extent, on the migration of arsenic in surface soil.%以我国粮食生产基地松嫩平原的北部为研究区域,分别采集表层土壤(0~20 cm)和深层土壤(1 m)样本,利用地统计学对土壤砷的空间分异特征进行量化,并结合ArcGIS软件的克里金插值方法分别对表层土壤和深层土壤进行土壤砷质量分数的水平空间分布格局模拟,分析了表层土壤砷和深层土壤砷的水平空间分异特征及其影响因素.研究表明:表层和深层土壤中砷元素质量分数均低于我国土壤砷元素质量分数背景值,属于砷元素质量分数较低、较为清洁健康的区域;深层土壤砷的水平空间格局强度相对较大,表层土壤砷的水平空间格局强度相对较小;表层土壤和深层土壤中砷元素的空间格局均为松嫩高平原土壤砷质量分数较高,松

  12. Experimental study on condensation of refrigerant-oil mixtures. Part 3; R-12 and R-22 on the external surface of single and multiple horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.C.Y.; Lin, S.; Fazio, P.; Jiang, Z. (Concordia Univ., Montreal, Quebec (CA))

    1989-01-01

    Presented are the test results of R-12 and R-22 on the external surface of horizontal finned tubes. The oil used in this study is alkylbenzene-based. Both pure refrigerant vapor tests and vapor-oil mixture tests were conducted at two different condensing temperatures-32.2{degrees} and 40.5{degrees}C (90{degrees} and 105{degrees}F), respectively. It was found that the presence of oil in R-12 and R-22 vapor with any mass radio lowers the condensing coefficient. However, the reduction of the condensing coefficient is not proportional to the percent of oil in the refrigerant vapors for the finned tubes. As for the pressure drop across the condenser, the effect of oil in the refrigerant vapors is not noticeable.

  13. Thermal design of horizontal tube boilers. Numerical and experimental investigation; Modelisation thermique de bouilleurs a tubes horizontaux. Etude numerique et validation experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Roser, R.

    1999-11-26

    This work concerns the thermal design of kettle reboilers. Current methods are highly inaccurate, regarded to the correlations for external heat transfer coefficient at one tube scale, as well as to two-phase flow modelling at boiler scale. The aim of this work is to improve these thermal design methods. It contains an experimental investigation with typical operating conditions of such equipment: an hydrocarbon (n-pentane) with low mass flux. This investigation has lead to characterize the local flow pattern through void fraction measurements and, from this, to develop correlations for void fraction, pressure drop and heat transfer coefficient. The approach is original, since the developed correlations are based on the liquid velocity at minimum cross section area between tubes, as variable characterizing the hydrodynamic effects on pressure drop and heat transfer coefficient. These correlations are shown to give much better results than those suggested up to now in the literature, which are empirical transpositions from methods developed for inside tube flows. Furthermore, the numerical code MC3D has been applied using the correlations developed in this work, leading to a modeling of the two-phase flow in the boiler, which is a significant progress compared to current simplified methods. (author)

  14. Film condensation of HCFC-123 on staggered bundles of horizontal finned tubes. Effect of fin geometry; Suihei fintsukikan no chidori kanbun ni okeru HCFC-123 no gyoshuku. Fin keijo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takada, N. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study; Makishi, O. [Kyushu University, Fukuoka (Japan); Sejimo, H. [NKK Corp., Tokyo (Japan)

    1995-03-25

    Experiments were conducted to obtain row-by-row heat transfer data during condensation of downward flowing HCFC-123 vapor in staggered bundles of horizontal two-dimensional fin tubes. Two conventional low fin tubes and two finned tubes with fin shapes close to that of a new high-performance fin proposed by Zhu and Honda were tested. The latter tubes had fin dimensions that were optimized by theoretical analysis. The heat transfer characteristics were compared with previous results for in-line bundles of the same test tubes and with theoretical predictions for stagnant vapor. The decrease in heat transfer due to condensate inundation was less significant for the staggered tube bundle. The highest heat transfer coefficient was provided by the staggered bundle of one of the new finned tubes. The theoretical predictions compared well with experimental data at a low vapor velocity and a low to medium condensate inundation rate. 15 refs., 10 figs., 2 tabs.

  15. 水平井可钻滤砂管的研制与应用%Research and application of drilled filter sand tube in horizontal wells

    Institute of Scientific and Technical Information of China (English)

    郑伟林

    2012-01-01

    水平井防砂容易形成卡管柱的现象,不易后期处理.通过对可钻型滤砂管外套、管材、胶结剂的选择与性能研究,研制出一种新型可钻的防砂工具.该工具将滤砂管防砂管柱的中心管、滤砂器、本体等均设计成可钻铣或可化学降解的材料,可以在其防砂失效后,通过钻头将其钻碎,将碎块冲出即可进行下一步作业,从而解决了防砂失效后难处理的问题.现场应用4口水平井,在1年内平均日增液33.8t,日增油3.9t,取得了显著的效果.该滤砂管挡砂精度可达0.07~0.13mm,井口产液含砂量小于0.05%,且砂粒粒径小于0.07mm,措施前后同期对比,产量稍有增加,满足了防砂要求.%At present, column sticking happens frequently during sand control process in horizontal wells and is very difficult to handle post processing. A new type drillable sand control implement has been developed by selecting materials and researching properties of drillable filter tube coats, pipes and cementing agents. All the materials used in implements including central tube, sand filter and sand control tube are designed to be drilling and milling and chemical degradation. Field application in 4 horizontal wells has launched, and the result indicates that obvious effects have been achieved with liquid increase of 33.81 per day and oil production of 3.91 every day. When the drillable filter sand tubes lose its effect, it can easily damage by bit and crash the fragments simply which followed by further treatments. Experimental results show that the sand blocking precision of this filter sand tube can up to 0.07~0.13 mm, and sand content of production liquid in wellhead is less than 0.05% with sand diameter smaller than 0.07 mm. The output rises slightly comparing before and after treatment, which can meet the requirements of sand control.

  16. Condensation of downward-flowing zeotropic mixture HCFC-123/HFC-134a on a staggered bundle of horizontal low-finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takata, N. [Kyushu Univ., Kasuga, Fukuoka (Japan). Inst. of Advanced Material Study

    1999-05-01

    Experiments were conducted to obtain row-by-row heat transfer data during condensation of downward-flowing zeotropic refrigerant mixture HCFC-123/HFC-134a on a 3 x 15 (columns x rows) staggered bundle of horizontal low-finned tubes. The vapor temperature and the HFC-134a mass fraction at the tube bundle inlet were maintained at about 50 C and 9%, respectively. The refrigerant mass velocity ranged from 9 to 34 kg/m{sup 2} s, and the condensation temperature difference from 3 to 12 K. The measured distribution of the vapor mass fraction in the tube bundle agreed fairly well with that of the equilibrium vapor mass fraction. The vapor phase mass transfer coefficient was obtained from the heat transfer data by subtracting the thermal resistance of the condensate film. The heat transfer coefficient and the mass transfer coefficient decreased significantly with decreasing mass velocity. These values first increased with the row number up to the third (or second) row, then decreased monotonically with further increasing row number, and then increased again at the last row. The mass transfer coefficient increased with condensation temperature difference, which was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient for the 4th to 14th rows was developed.

  17. PARTICULARITIES REGARDING THE OPERATING PROCESS OF THE CUTTING AND EXTRACTION DEVICE IN THE CANDU HORIZONTAL FUEL CHANNELS PRESSURE TUBE DECOMMISSIONING PART I: MOVEMENT AND FIXING DEVICE INSIDE THE PRESSURE TUBE

    Directory of Open Access Journals (Sweden)

    Constantin POPESCU

    2016-05-01

    Full Text Available This paper presents some details of operation process for a Cutting and Extraction Device (CED in order to achieve the decommissioning of the horizontal fuel channels pressure tube in the CANDU 6 nuclear reactor. The most important characteristic of the Cutting and Extraction Device (CED is his capability of totally operator’s protection against the nuclear radiation during pressure tube decommissioning. The movement and fixing processes present few particularities due to special adopted technical solutions: train guiding-fixing modules equipped with elastic guiding rollers and fixing claws, traction modules with elastic rollers and variable pitch, also with propriety to adapt the system according to various dimensions of the tube. The Cutting and Extraction Device (CED is a train of modules equipped with special systems to be fully automated, connected with a Programmable Logic Controller (PLC and controlled by an operator panel type Human Machine Interface (HMI. All processes are monitored by video cameras. In case of error, the process is automatically stopped, the operator receiving an error message and the last sequence could be reinitialized or aborted due to safety reasons

  18. Research on natural condensation heat transfer characteristics on horizontal finned tube%水平肋片管外自然凝结传热特性研究

    Institute of Scientific and Technical Information of China (English)

    李慧君; 董楠; 王炯

    2015-01-01

    基于 Nusselt凝结传热理论,沿肋片管圆周方向划分有限个微元角,建立了每个微元角内肋侧壁、肋间基管及肋顶三个区域的凝结传热模型,通过求解非淹没区和淹没区总传热量,推导管外平均传热系数计算式。计算不同肋片高度、肋密度时,R134a饱和蒸汽的管外平均凝结传热系数。结果表明:随肋密度的增加,平均传热系数先增大后减小,肋密度为25 fpi时传热最佳;高肋片管的平均凝结传热系数大于低肋片管的,肋片高度达到一定值时,平均传热系数几乎不随肋高增加而增加。当 R134a 饱和蒸汽为20℃时,两种不同翅片密度的管外平均凝结传热系数随温差的增大而减小,并通过所建模型得到的计算值与 Beatty-Kate 模型进行了比较,平均误差分别为约16.1%和8.3%,故所建模型基本反映肋片管外蒸汽凝结传热机理。%Presents an analytical model to calculate the condensation heat transfer coefficient on horizontal finned tube based on the Nusselt condensation heat transfer theory.The employs an elemental calculation by dividing the tube wall into finite elements to establish the condensate heat transfer model of the fin flank,the channel between fins and the fin tip in the small annular element. The model can predict the mean condensation heat transfer coefficient outside finned tubes by calculating the total heat transfer.The average condensation heat transfer coefficient of the saturated steam R134a outside the pipe versus fin heights ,fin densities were then calculated.The results show that the average heat transfer coefficient first increases and then decreases with the increase of fin density.The optimum fin density is 25 fpi an the average condensation heat transfer coefficient of the higher finned tube is greater than that of lower finned tube.The average heat transfer coefficient hardly increased with the increase of fin height until it reaches a certain value

  19. Heat transfer when melting in the horizontal concentric annular gap and on finned tubes. Die Waermeuebertragung beim Schmelzen im horizontalen konzentrischen Ringspalt und am Rippenrohr

    Energy Technology Data Exchange (ETDEWEB)

    Betzel, T.

    1986-01-01

    Heat transfer in melting processes has aroused a great deal of interest recently because of the possibilities of using latent heat stores. Starting from explanations of the areas of use for latent heat stores, the possible storage media and types of store construction for active heating systems, there is an introductory phenomenological description of the melting process on resting and moving bodies and a survey of the literature. The melting and solidification processes due to purely thermal conduction (on plane walls, on cylindrical surfaces, in the concentric annular gap) and the differential equations decisive for the convection melting process are then explained. The melting process in the concentric annular gap with a falling solid body and the melting process around a horizontal tube with and without axial fins were also examined (density of heat flow, rate of melting, superimposition of boundary layer, phase boundaries). (HWJ).

  20. 小口径水平固定管组合焊技术探索%Study on Composite Welding Technique for Small-caliber Horizontal Fixed Tubes

    Institute of Scientific and Technical Information of China (English)

    孙炎; 黄凤虎

    2013-01-01

    This article studies composite welding technique for small-caliber horizontal fixed tubes from such angles as its cleaning before welding, welding fabrication, welding techniques (SMAW and TIG welding), processing parameter, welding operation, welding inspection so as to improve the welding quality.%文章针对小口径水平固定管组合焊,研究了其焊前清理、焊接装配、焊接方法(焊条电弧焊和TIG焊)、工艺参数、操作方法、焊接检验等方面技术,对提高焊接质量具有一定的应用价值。

  1. Experimental study on heat transfer enhancement of laminar ferrofluid flow in horizontal tube partially filled porous media under fixed parallel magnet bars

    Science.gov (United States)

    Sheikhnejad, Yahya; Hosseini, Reza; Saffar Avval, Majid

    2017-02-01

    In this study, steady state laminar ferroconvection through circular horizontal tube partially filled with porous media under constant heat flux is experimentally investigated. Transverse magnetic fields were applied on ferrofluid flow by two fixed parallel magnet bar positioned on a certain distance from beginning of the test section. The results show promising notable enhancement in heat transfer as a consequence of partially filled porous media and magnetic field, up to 2.2 and 1.4 fold enhancement were observed in heat transfer coefficient respectively. It was found that presence of both porous media and magnetic field simultaneously can highly improve heat transfer up to 2.4 fold. Porous media of course plays a major role in this configuration. Virtually, application of Magnetic field and porous media also insert higher pressure loss along the pipe which again porous media contribution is higher that magnetic field.

  2. Experimental investigation on thermo-physical properties and overall performance of MWCNT-water nanofluid flow inside horizontal coiled wire inserted tubes

    Science.gov (United States)

    Akhavan-Behabadi, M. A.; Shahidi, Mohamad; Aligoodarz, M. R.; Ghazvini, Mohammad

    2017-01-01

    The present study is aimed to measure and analyze the thermo-physical properties and overall performance of MWCNT-water nanofluid in turbulent flow regimes under constant heat flux conditions inside horizontal coiled wire inserted tubes. For this purpose, stable MWCNT-water nanofluids with different particle weight fractions of 0.05, 0.1 and 0.2 % as well as deionized water were utilized as the working fluids. It was found that the existing theoretical models could not predict the thermo-physical property values accurately, especially in case of specific heat capacity. Therefore, new empirical correlations are presented based on the obtained experimental results to predict such properties for the nanofluids. In addition, the overall performance of heat transfer techniques considered in this paper was evaluated based on thermal performance factor. The results revealed that thermal performance factor for all cases are greater than unity which indicate that simultaneous usage of nanofluids and wire coil inserts enhances the heat transfer without huge penalty in pumping power. Hence, using nanofluids as the working fluid in combination with coiled wire inserted tubes can be considered for some practical applications.

  3. Film condensation of HCFC-123 on in-line bundles of horizontal finned tubes. Effect of fin geometry. Suihei fin tsuki kan no gobanme kangun ni okeru HCFC-123 no gyoshuku. Fin keijo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takada, N. (Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study); Kim, K. (Kyushu University, Fukuoka (Japan)); Ishikawa, Y. (Otsuka Pharmaceutical Co. Ltd., Tokyo (Japan))

    1994-06-25

    Theoretical analysis and experiments were carried out in regard to the condensation of HCFC-123 vapor on a horizontal finned tube. The previous paper described the theoretical analysis on the film condensation in a tube nest with low-fins. In this study, approximate expressions of heat transfer coefficient for a newly proposed high-performance finned tubes are suggested and compared with the experimental results. In the test, HCFC-123 vapor was flowed from the upper part of the tube nest arranged in squares of 3 rows and 15 layers (tube pitch: 22mm), and was condensed on the tube surface. The liquid film formation was observed, and the heat transfer properties were measured. Two kinds of conventional low-fin tubes and two kinds of finned tubes of which shape is similar to the newly proposed ones were tested. One of the new finned tubes showed the highest heat transfer performance, which was about 85% higher than that of the conventional low-fin (26 fpi) tube. The theoretical model for condensation in the previous paper was correspondent with the experimental data at low vapor speed and low condensate inundation rate. 14 refs., 14 figs., 4 tabs.

  4. Horizontal convective boiling of R448A, R449A, and R452B within a micro-fin tube

    Science.gov (United States)

    KEDZIERSKI, MARK A.; KANG, DONGGYU

    2017-01-01

    This article presents local convective boiling measurements in a micro-fin tube for three low global warming potential refrigerants: R448A, R449A, and R452B1. An existing correlation was modified to predict multi-component mixtures, which predicted 98% of the measurements to within ±20%. The new correlation was used to compare the heat transfer coefficient of the three test fluids at the same heat flux, saturated refrigerant temperature, and refrigerant mass flux. The resulting comparison showed that refrigerant R452B exhibited the highest heat transfer, in large part due to its approximately 28% larger liquid thermal conductivity and smaller temperature glide as compared to the tested low-global warming potential refrigerants. For the example case, the heat transfer coefficient for R449A was approximately 8% larger than that for R448A, while the heat transfer coefficient for R452B was more than 59% larger than either R448A or R449A. The heat transfer coefficients for R448A and R449A were roughly between 26 and 48% less than that of R404A for the example case. In contrast, the model predicts that the R452B heat transfer coefficient was approximately 13% larger than that of R404A for the same conditions. PMID:28758148

  5. 冰浆在水平直管中流动特性研究∗%Study on flow characteristics of ice slurry in horizontal straight tubes

    Institute of Scientific and Technical Information of China (English)

    刘圣春; 李奥; 郝玲; 周庆; 卢君; 怀超平; 刘雪莹

    2016-01-01

    Ice slurry is widely used in practical application by the means of being trans-ported to the heat exchanger through piping systems,so it is of great significance for the ice slurry to investigate the flow characteristics and heat transfer behavior to improve the application effects.Pressure drop is mainly affected by the volume fraction,the diameter, viscosity,flow velocity of ice crystals and tube parameters.The horizontal straight tube is one of the simplest piping types.In present,research mostly focuses on the experimental measurements and modification of theoretical model,which are not uniform.Based on du-al-Euler fluid model and phase change heat exchange,the influences of tube diameters, volume fraction,flow velocities and tube length on the pressure drop are analyzed qualita-tively using simulation method.Additionally,the distribution of ice crystals at cross-sec-tion is derived taking account of the phase change between the ice crystals and water.%冰浆在实际中的应用大多是先通过管道输送的方式到达需要冷却的地方进行热交换,研究输送过程中的流动换热特性对改善其实际应用效果具有重要意义。流动压降主要受到含冰率、冰粒直径、黏度、流速以及管径、管长和管道形状的影响。水平直管是最简单的管道形式之一,目前国内外学者研究方法主要是结合试验方法和数值模拟对已有的理论模型进行修正,尚未有统一的理论模型。本文采用数值模拟的方法,在双欧拉流体理论模型和相变换热基础上,定性分析流动过程中的压降受管径、含冰率、流速和管长的影响,并且在考虑冰晶和水两相相变的情况下,得到直管横截面上冰晶的分布情况。

  6. Growth of Horizontal Semiconducting SWNT Arrays with Density Higher than 100 tubes/μm using Ethanol/Methane Chemical Vapor Deposition.

    Science.gov (United States)

    Kang, Lixing; Zhang, Shuchen; Li, Qingwen; Zhang, Jin

    2016-06-01

    Horizontally aligned semiconducting single-walled carbon nanotube (s-SWNT) arrays with a certain density are highly desirable for future electronic devices. However, obtaining s-SWNT arrays with simultaneously high purity and high density is extremely challenging. We report herein a rational approach, using ethanol/methane chemical vapor deposition, to grow SWNT arrays with a s-SWNT ratio over 91% and a density higher than 100 tubes/μm. In this approach, at a certain temperature, ethanol was fully thermally decomposed to feed carbon atoms for Trojan-Mo catalysts growing high density SWNT arrays, while the incomplete pyrolysis of methane provided appropriate active H radicals with the help of catalytic sapphire surface to inhibit metallic SWNT (m-SWNT) growth. The synergistic effect of ethanol/methane mixtures resulted in enriched semiconducting SWNTs and no obvious decrease in nanotube density due to their milder reactivity and higher controllability at suitable growth conditions. This work represents a step forward in large-area synthesis of high density s-SWNT arrays on substrates and demonstrates potential applications in scalable carbon nanotube electronics.

  7. AN EXPERIMENTAL STUDY FOR HEAT TRANSFER ENHANCEMENT BY LAMINAR FORCED CONVECTION FROM HORIZONTAL AND INCLINED TUBE HEATED WITH CONSTANT HEAT FLUX, USING TWO TYPES OF POROUS MEDIA

    Directory of Open Access Journals (Sweden)

    Thamir K. Jassem

    2013-05-01

    Full Text Available An experimental forced laminar study was presented in this research for an air flowing through a circular channel for different angles ( ,30o,45o,60o, the channel was heated at constant heat flux , the channel also was packed with steel and glass spheres respectively . The tests were done for three values of Peclets number (2111.71,3945.42,4575.47 with changing the heat flux for each case and five times for each number.The results showed that the dimensionless temperature distribution  will decrease with increasing the dimensionless channel length for all cases with changing Peclet number, heat flux and inclination angles, and its lowest value will be for glass spheres at highest flux, while at lower flux for , and the decreasing in dimensionless temperature was closed for both types of packed at other inclination angles.The study declared that the local Nusselt number decreases with increasing the dimensionless length of the channel for both packeds and for different applied heat flux, also through this study it was declared that the average Nusselt increases as Peclet number increases for both packed. Its value for the glass spheres is greater than the steel spheres with percentage (98.3% at small Peclet, and percentage (97.2% at large Peclet number for the horizontal tube, and (98.3% at small Peclet number and (97.8% at large Peclet number at  .Through this study its was found that average Nusselt number increases along the channel as the heat flux increases, because the bulk temperature will increase as the flow proceeds toward the end of the channel , so the heat transfer coefficient will increase.  It was declared from this study that in the case of the steel packed the heat transfer will occur mainly by conduction, while in the case of glass packed the heat transfer will occur mainly by laminar forced convection, where the lowest Nusselt number (Nu=3.8 was found when the pipe is horizontal and lowest heat flux and lowest Peclet number.  

  8. THE STUDY ON CONDENSATION HEAT TRANSFER CHARACTERISTICS FOR VAPOR FLOW IN HORIZONTAL AND VERTICAL SMALL DIAMETER TUBES%水平和竖直细圆管内流动凝结换热特性的对比研究

    Institute of Scientific and Technical Information of China (English)

    王补宣; 杜小泽

    2000-01-01

    本文采用基于相平衡理论的最小能量原理,根据当地气液两相流动条件确定气液界面形状,以此为基础,从理论上探讨水平细圆管内流动凝结的特点。通过与竖直条件下管内凝结换热特性的对比,分析重力、气液界面剪切力、表面张力对流动凝结的影响。研究发现,细圆管由竖直变为水平放置时,管径的减小同样导致重力的影响削弱,并且凝结换热得到进一步强化;但由于流型的变化,随管径的减小强化的程度减弱。%Employing the minimum energy principle to determine the vapor-liquid interfaceconfiguration, this paper established an analytical model to explore the heattransfer characteristics of flow condensation in horizontal small/mini diametertube. Compared with that in vertical tube, the effects of shear stress, surfacetension and gravity on flow condensation are analyzed. The results indicatethat, both in vertical and horizontal tube, decreasing the tube diameter leadsto the gravity effect weakening, and as the tube is located from vertical tohorizontal, condensation is enhanced. However, in small diameter tube, becauseof vapor-liquid interface curvature increasing, the heat transfer enhancementisn't as obvious as that in large diameter tube.

  9. The Heat Transfer and Enhancement Mechanism in Inner Tube of the Horizontal Thermosiphon Evaporator%卧式热虹吸式蒸发器的管内蒸发传热及强化

    Institute of Scientific and Technical Information of China (English)

    熊从贵; 何静; 林翔; 林通; 刘雪飞

    2016-01-01

    Introduces the structure and working principle of the horizontal thermosiphon evaporator. The thermosiphon evaporator in industrial refrigeration system use of cycle power by height difference and density difference of the refrigerant, The height and density difference is larger, The refrigerant circulating ratio of in evaporator is greater, more conducive to heat transfer. The refrigerant flow in the horizontal tube, the annular convex ribs of tube makes the refrigerant in the tube periodically formed whirlpool, increase turbulent degree of the tube bottom liquid, thinning of the heat transfer boundary layer thickness, improve the heat transfer coefficient of the tube.%介绍了卧式热虹吸式蒸发器的结构和工作原理。工业制冷系统中的热虹吸式蒸发器是利用制冷剂的位差和密度差作为循环动力。位差和密度差越大,蒸发器中的制冷剂循环倍率越大,更有利于传热。制冷剂在水平管内流动时,换热管上的环形凸肋使管内制冷剂周期性地形成漩涡,增加了换热管内底层液体的湍动程度、减薄了传热边界层厚度,提高了换热管内的传热系数。

  10. 纳米流体水平管内沸腾流型的模拟研究%Simulation of the boiling flow pattern in the nanofluid horizontal tube

    Institute of Scientific and Technical Information of China (English)

    聂宇宏; 周长江; 姚寿广; 王公利

    2013-01-01

    Programming through a UDF definition of nanofluid phase change source term , the Al2 O3 -H2 O nanofluid boiling process is simulated in the horizontal tube ,and the boiling flow pattern characteristics analyzed in the nanofluid horizontal tube .The results show that for boiling in the horizontal pipe , the gas content increases along the length direction , but in the same interface position , the nanofluid of air content is higher than that of pure water of air content ,helpful to enhance the disturbance of the fluid .For different concentrations of Al 2 O3 -H2 O nanofluid flow pattern , particle concentration has little effect on nanofluid tube boiling process .Nanofluid is then compared with pure water flow pattern , the results show that the Al 2 O3 -H2 O nanofluid makes tube boiling more intense and easier .It will improve the flow characteristic of the horizontal circular tube .%利用UDF编程定义纳米流体相变源项,对Al2O3-H2O纳米流体在水平管内的沸腾过程进行了数值模拟,分析研究了纳米流体在水平管内沸腾的流型特点,结果表明水平管内沸腾蒸发产生的相变含气率沿着管长方向不断增加,但相同截面位置纳米流体的含气量高于纯水的含气量,有助于强化流体的扰动与混合。对于不同浓度的Al2O3-H2O纳米流体的流型研究表明:颗粒浓度对于纳米流体管内沸腾过程的影响不大。随后将纳米流体与纯水的流型进行比较,结果表明Al2O3-H2O纳米流体使得管内沸腾更剧烈,也更容易沸腾,这将改善水平圆管的流动特性。

  11. 管束效应对HFC245fa与HCFC123膜状凝结换热影响%Effect of Inundation on Film Condensation of HFC245fa and HCFC123 on Horizontal Tubes

    Institute of Scientific and Technical Information of China (English)

    马志先; 张吉礼; 孙德兴

    2012-01-01

    建立试验系统、改进试验方法,试验研究HFC245fa与HCFC123在光管与3种强化换热管(2D-A,3D-A与3D-B)管束外冷凝换热特性.试验管束由4列排深为5排的列管构成,换热管公称外径为19.05 mm、有效换热长度为500 mm.试验中,利用改进的Wilson图解法获得水侧对流传热系数,通过轮转试验方法消除管束试验中各试验管换热本构差异等因素对管束效应测试分析的影响.试验结果表明,Kern模型预测值与HFC245fa与HCFC123光管管束外凝结换热结果偏差随试验热通量升高而增大;管束效应对光管与三维表面强化管(3D-B)凝结换热影响比其对二维表面低肋管(2D-A)影响显著;管束效应对HFC245fa在3D-B管外凝结换热影响在n>3后超过Nusselt管束模型预测值;HFC245fa在3D-B管束外凝结换热性能随管排深度的变化规律与其在光管管束外的变化规律及Nusselt模型显示规律明显不同.%A test facility was constructed to perform shell-side condensation testing, and test results are presented for HFC245fa and HCFC123 using horizontal tube bundles (4 lines×5 rows) consist of smooth tubes and 2D-A, 3D-A and 3D-B enhanced tubes. Effect of inundation on the condensation heat transfer coefficient (CHTC) is considered in the study. The nominal diameter of test tubes is 19.05 mm and the active length of the test section is 500 mm. In the experiment, water-side convection heat transfer coefficient of enhanced tube was gained by modified Wilson plot method and the tube row effect is studied by a designed method with high precision. The results show that the deviation between CHTC of HCFC123 and HFC245fa on smooth tube bundle and that predicted by Kern's model increased with the increase of heat flow rate; Inundation effect significantly affects CHTC of smooth and 3D-B tubes, but lightly affects that of 2D-A tubes; Inundation effect of HFC245fa on 3D-B tubes is more severity than that predicted by Nusselt model for

  12. Analysis of the turbulence anisotropy characteristic in the interface of gas-liquid two phase flow in horizontal tubes%水平管内气液两相流界面湍流各向异性分析

    Institute of Scientific and Technical Information of China (English)

    邱国栋; 蔡伟华; 姜益强

    2016-01-01

    In order to explore how to choose the turbulence model of the gas-liquid two phase flow in a horizontal pipe, the guess that the turbulence of the interface of the gas-liquid two phase flow in a horizontal pipe is anisotropic was put forward. The emergence and development mechanism of the turbulence anisotropy in the interface was analyzed. It points out that the turbulence inertial force generated by the turbulence anisotropy in the interface is an important reason for the formation of annular flow in a horizontal tube, which was verified by comparing the simulation results of using the two-equation model and Reynolds stress model ( RSM) to simulate the same working condition of annular flow in a horizontal tube. On such basis, the basis of selecting turbulence model in gas-liquid two phase flow was discussed. The results show that the RSM model is adaptive for large gas-liquid shear stress in a horizontal pipe, while the two-equation model and RSM model are both adaptive for other conditions.%为探讨水平管内气液两相流湍流模型如何选择,提出水平管内气液两相流界面湍流为各向异性的猜想,分析了该界面湍流各向异性产生和发展的机理,指出界面湍流各向异性产生的湍流惯性力是水平管环状流形成的重要原因.通过比较二方程模型和雷诺应力模型( RSM)模拟同一个水平管环状流工况的结果来验证分析的正确性,在此基础上探讨了气液两相流湍流模型的选择依据.结果表明当水平管内气液剪切力较大时适合选用RSM模型,其他情况二方程模型和RSM模型均适用.

  13. Effects of V-type ducts on condensation heat transfer of HFC245fa on horizontal tube bundles%V型导液槽对HFC245fa水平管束外冷凝换热影响

    Institute of Scientific and Technical Information of China (English)

    马志先; 张吉礼; 孙德兴

    2011-01-01

    试验研究了HFC245fa在水平光管与强化管管束外的冷凝换热特性,提出在管束中加装V型导液槽来消除管束效应的方法,并通过试验研究了V型导液槽对管束冷凝换热特性的影响.试验管束由4列排深为5排的列管构成,带导液槽管束的前4排管下方加装了两段长度为450 mm的导液槽;试验换热管公称外径为19.05 mm、换热长度为1000 mm.试验中,以Wilson描点法获得强化换热管水侧对流传热系数,以对比试验方法研究了V型导液槽对水平管束外冷凝换热性能的影响.结果表明:传统的管束效应模型仅在较小的热通量范围适用;凝液在管间的迁移形态与流态随管上作用凝液量的系列变化是导致管束效应变化的主要因素;加装导液槽可有效控制凝液在管间的迁移,控制管束效应;加装导液槽使光管单管冷凝传热能力下降10%左右,使光管管束总体换热能力提升4.5%~9.5%;加装导液槽对强化管单管冷凝换热性能的影响比对光管影响强近4倍.本文研究成果对引入导液槽开发新型高效卧式冷凝管束具有指导意义.%In a horizontal condensation tube-bundle, the inundation effect, resulted from local condensation film and falling condensate from upper tube rows, may reduce the condensation heat transfer coefficient (CHTC) considerably. This paper presents an experimental study on condensation heat transfer characteristic of HFC245fa on horizontal tube bundles. A scheme was proposed to reduce the tube row effect resulted from falling condensate with V-type ducts, and the effect of the duct on CHTC of the tube bundles was investigated experimentally. The tube bundle consisted of 4 columns, each with 5 tubes, with smooth tubes and enhanced tubes, separately. Two columns out of the four were equipped with the duct. The equivalent outside diameter and effective length for heat transfer of tubes were 19.05 mm and 1000 mm respectively. In the experiment, water

  14. Non azeotrope mixing refrigerating fluids condensation outside of an horizontal tubes stack; Condensation de melanges non azeotropes de fluides frigorigenes a l'exterieur d'un faisceau de tubes horizontaux

    Energy Technology Data Exchange (ETDEWEB)

    Signe, J.Ch.

    1999-04-16

    The development of non-azeotrope mixing, as regular refrigerating fluids substitute, calls in question the experience for the design of refrigerating and cooling machinery. Studies to better understand these fluids behaviour are necessary. The aim of this thesis is the knowledge enlargement on the pure fluids and non azeotrope mixing condensation, outside of a tubes stack, and to simulate the heat transfers. The tubes stack is a condenser, type TEMA X often used in refrigerating machinery. The binary mixing HFC 134a-HFC23, allows a large sliding scale. (A.L.B.)

  15. 基于分布参数模型的水平管式降膜蒸发器模拟%Prediction of the Performance of Falling Film Evaporator with Horizontal Tube Bundle Based on a Distributed Parameter Model

    Institute of Scientific and Technical Information of China (English)

    翟玉燕; 黄兴华

    2009-01-01

    A distributed parameter model is developed for predicting the performance of a horizontal-tube falling-film evaporator. In this model, the variation of heat transfer performance along the tube length and array, as well as the effect of the dry patch on the performance are considered. The model is applied to predicting the performance of a commercial falling film evaporator, and the influences of bundle layout, pass layout, refrigerant mass flow rate and the flooded level of refrigerant on the evaporator performances are studied. The results show that the simulation result agrees well with the experimental data, and it is possible to decrease or avoid the dry patch area on the tube bundle and therefore improve the evaporator performance by rationallly designing the layout of the tube bundle and the flooded level of the refrigerant.%建立水平管式降膜蒸发器蒸发换热的分布参数模型,考虑换热性能沿管子轴向、管排方向的变化,以及传热管发生干斑现象时对降膜蒸发的影响.对一降膜蒸发器的性能进行模拟分析,并考察管束布置、制冷剂液膜质量流量、管程布置以及满液位置对降膜蒸发器性能的影响.结果表明,计算结果和试验结果吻合良好,通过合理的设计管排方式和满液位置,可以减少或避免干斑现象的发生,提高降膜蒸发器性能.

  16. CO2水合物浆在水平圆管中的传热特性%Heat transfer characteristics of CO2 hydrate slurry in horizontal circular tube

    Institute of Scientific and Technical Information of China (English)

    刘妮; 由龙涛; 张亚楠; 柳秀婷

    2015-01-01

    The flow and heat transfer characteristics of CO2 hydrate slurry in horizontal circular tube was studied experimentally. The dissociation properties of CO2 hydrate slurry was investigated using the electric heating water around the tube method. The analysis of phase transition and heat transfer characteristics of CO2 hydrate slurry indicated that the phase transition temperature of CO2 hydrate slurry was at 8—12℃. The heat transfer characteristics of CO2 hydrate slurry with 13.2%(vol) solid fraction in a 8 mm straight stainless steel horizontal circular tube were studied at the flow rate of 0.45 m/s in a dynamic loop. The corresponding local convective heat transfer coefficient in horizontal circular tube increased and then stayed constant and the range was calculated to be 1500—1800 W/(m2·K). The results showed that the largest corresponding convective heat transfer coefficient appeared in the phase transition field of CO2 hydrate slurry. The influences of heating power on tube wall temperature and the convective heat transfer coefficient were discussed respectively. It was discovered that the heating power had a strong effect on wall temperature. The phase transition effect of CO2 hydrate slurry can be used to enhance the heat transfer and increase the heat transfer efficiency in related applications.%在 CO2水合物浆流动传热特性测试实验系统上,采用套管式电加热的方法对CO2水合物浆进行了分解实验,并对CO2水合物浆的流动传热特性进行了分析。对CO2水合物浆的相变特性进行了研究,得到CO2水合物浆的相变温度在8~12℃。研究了在固相体积分数为13.2%以及流速为0.45m/s的条件下CO2水合物浆在内径为8mm的水平不锈钢管中的传热特性,计算得到CO2水合物浆在不锈钢水平圆管中的对流传热系数为1500~1800 W/(m2·K),并且其在流动传热过程中呈现先增大随后趋向平稳的趋势,在水合物的相变区相应的对流传

  17. Coiled Tubing Fishing Process Application Problems and Measures in Horizontal Well%连续油管打捞工艺在水平井的应用问题及措施

    Institute of Scientific and Technical Information of China (English)

    吴永兴; 朱培珂; 熊伟

    2016-01-01

    coiled tubing in horizontal well is used for fishing operation,the method for judging whether get the fish by the changing of hang weight and the raising of instantaneous pump pres-sure in horizontal section is infeasible.13-meter-long down hole tool fell into the horizontal sec-tion in the combination process of pumping bridge and perforation in well X2-2,one shale gas.The cause of the failure in the three previous fishing operations is analyzed.Lastly,the fishing was a-chieved successfully by improving the method for aligning the fishing tool and fish,employing screw motor and changing fishing socket.%在水平井中采用连续油管进行打捞作业,不能通过悬重变化和泵压的瞬时升高来判定是否抓住落鱼,打捞的难度大。以某页岩气区块 X2-2井为例,在泵送桥塞与射孔联作的过程中,13 m 长的工具串落入水平井的水平段内。分析了前3次打捞失败的原因。通过改进打捞工具与落井工具的对中方法,增加螺杆马达,更换打捞筒,第4次打捞获得成功。

  18. Horizontal Displacement Monitoring Technology of the Ningbo Changhong Immersed Tube Tunnel%宁波市常洪隧道沉管接缝平面位移监测技术探讨

    Institute of Scientific and Technical Information of China (English)

    袁峥; 杨锦波; 刘俊伟

    2012-01-01

    监测项目中的测边网通常被用于大型工程,本文结合宁波市常洪隧道沉管接缝的结构特点,将测边网的方法引入隧道狭小的空间中,利用简单的钢尺测量手段,结合拟稳平差方法,成功对隧道沉管结构的相对位移实施了监测,有力保障了隧道的运营安全。%This article uniting the characteristic of the Ningbo Changhong immersed tube tunnel, introduced the mini -trilateration network into tunnel in the narrow space, which used simple ruler measurement methods and imitative stable adjustment. The success of horizontal displacement monitoring for the Ningbo Changhong immersed tube tunnel,powerful safeguard the tunnel operation safety.

  19. 润滑油对水平强化管降膜蒸发传热特性的影响%Effect of Lubricating Oil on Heat Transfer Performance of Falling Film Evaporation on Horizontal Enhanced Tube

    Institute of Scientific and Technical Information of China (English)

    李敏霞; 蔡文生; 孙晗; 党超镔; 吕佳桐

    2015-01-01

    实际制冷系统中的制冷剂含有压缩机的润滑油.本文研究了制冷剂中润滑油不同含油率时水平管降膜式蒸发传热特性.工质为R134a,含油率分别为0.5%、1.2%、5.1%,蒸发温度为6,℃,热流密度范围为30~65,kW/m2,工质喷淋密度分别为0.13,kg/(s·m),0.17,kg/(s·m)、0.21 kg/(s·m),测试段采用表面强化的铜管.实验结果表明:含油率从0.5%增大到5.1%,管外传热性能逐渐提高,当喷淋密度增加,管外换热系数也会提高,但随着含油率的增加,换热系数的增加幅度不大;一定含量的润滑油能增大R134a水平管降膜蒸发的换热系数.%In engineering practice,refrigerant contains lubricating oil form compressor in the refrigerating system. In this study,the impact of different oil contents on evaporation of falling film on horizontal enhanced tube was dis-cussed. Experiments were conducted for R134a at the saturation temperature of 6,℃ on enhanced copper tube,with oil contents being 0.5%,1.2% and 5.1%,respectively,and heat fluxes ranging from 30,kW/m2 to 65,kW/m2, sprinkle densities being 0.13,0.17,and 0.21,kg/(s·m). The experimental results show that heat transfer coefficient of the outside horizontal enhanced tube increases with both oil contents growing from 0.5% to 5.1% and increasing sprinkle densities. However,with the augments of oil contents,the increases of heat transfer coefficient are nearly insensitive to the increasing sprinkle densities. In certain range of content,lubricating oil can improve heat transfer coefficient of R134a falling film evaporation.

  20. MEASUREMENT AND CORRELATION OF FLOW BOILING HEAT TRANSFER OF R600a/COMPRESSOR OIL SOLUTION INSIDE A HORIZONTAL SMOOTH TUBE

    Directory of Open Access Journals (Sweden)

    А.V. Melnyk

    2015-08-01

    Full Text Available Experimental results of local heat transfer coefficients for the boiling of real working fluids (solutions of R600a with mineral naphthenic oil ISO VG 15 in smooth tube with small diameter (5.4 mm are presented. The tests were carried out for the inlet pressure in the range from 71.1 kPa to 77.9 kPa, heat flux was 3800 W/m2, and mass velocity of working fluid was from 14.75 to 18.36 kg/(m2s. The quantitative estimation in reduction of heat transfer coefficient of the wetted surface in evaporator at high oil concentration in the mixture is made. The influence of mass velocities of the working fluid on the values of the local heat transfer coefficients are analyzed. Based on the results obtained it was observed that increasing mass velocity leads to increase the local heat transfer coefficient of RWF both on side of wetted perimeter and vapor phase. The equation for the modeling of the local heat transfer coefficient for boiling of isobutane/compressor oil solution flow in the pipe is suggested.

  1. Horizontal Accelerator

    Data.gov (United States)

    Federal Laboratory Consortium — The Horizontal Accelerator (HA) Facility is a versatile research tool available for use on projects requiring simulation of the crash environment. The HA Facility is...

  2. Numerical Simulation on Cuttings Carrying Regularity for Horizontal Wells Drilled with Coiled Tubing%连续油管钻水平井岩屑运移规律数值模拟

    Institute of Scientific and Technical Information of China (English)

    宋先知; 李根生; 王梦抒; 易灿; 苏新亮

    2014-01-01

    During the course of drilling horizontal well with coiled tubing ,cuttings easily settle on the low side of borehole to form cuttings bed due to action of gravity .The features in the coiled tubing drilling , such as small pumping rate and no rotation in drill string etc ,have made hole cleaning efficiency very low . In view of this problem ,considering the interphase slip velocity and particle flow influence based on the Eu-lerian coordinate system ,a mixture drift model of cuttings carrying in a horizontal slim-hole was estab-lished ,w hich uses Realize κεturbulence model and the SIM PLEC algorithm for numerical calculation ,and studied the effects on eccentric annular cuttings migration by flow rate ,annular eccentricity ,cuttings size , mud viscosity and hole angle ,to determine distribution pattern of cuttings velocity and concentration in an-nular space under all conditions .The study shows that cuttings carrying efficiency will increase in coiled tubing drilling horizontal wells with the change of several factors ,i .e .the increase of flow rate of drilling fluid ,the decrease of annular eccentricity ,decrease of cuttings size and well inclination ,and the increase of mud viscosity .%连续油管钻水平井过程中,井底岩屑在重力作用下容易沉积在井壁下侧,形成岩屑床;连续油管又受到排量小、钻柱无法旋转等因素限制,造成井眼净化效率较低。针对这一问题,在欧拉坐标系下考虑相间滑移速度和颗粒流的影响,建立了微小井眼水平井岩屑运移的混合物漂移模型,采用Realize κε湍流模式及SIMPLEC算法进行数值计算,研究了钻井液排量、环空偏心度、岩屑直径、井斜角和钻井液黏度等参数对偏心环空岩屑运移的影响,得到了各种条件下环空岩屑速度和浓度的分布规律。研究表明:随着钻井液排量增大、环空偏心度减小、岩屑直径减小、井斜角减小及钻井液黏度提高,连续

  3. Local Flow Regime Transition Criteria of Gas-Liquid Two-phase Flow in Vertical Upward Tube with a Horizontal Rod%垂直上升管内有水平柱体时气液两相局部流型转变的研究

    Institute of Scientific and Technical Information of China (English)

    胡志华; 杨燕华; 刘磊; 周芳德

    2006-01-01

    The upward multiphase cross flow and heat transfer in the vertical tube may occur in oil production and chemical facilities. In this study, the local flow patterns of an upward gas-water two phase cross flow in a vertical tube with a horizontal rod have been investigated with an optical probe and the digital high speed video system. The local flow patterns are defined as the bubble, slug, churn and annular flow patterns. Optical probe signals are analyzed in terms of probability density function, and it is proved that the local flow patterns can be recognized by this method. The transition mechanisms between the different flow patterns have been analyzed and the corresponding transitional models are proposed. Finally, local flow pattern maps of the upward gas-water two-phase flow in the vertical tube with a horizontal rod are constructed.

  4. 加金属丝水平单圆管蓄冰数值模拟%Ice Storage Numerical Simulation of Horizontal Single Circular Tube Added with Wire

    Institute of Scientific and Technical Information of China (English)

    钟亮; 潘阳

    2011-01-01

    Shortcomings of the ice-on-coil thermal storage heat appear in the ice. Adding some metal wire around the tube may improve freezing efficiency. In order to describe the result of freezing process on extended surface, regarding wire and water mixing region as porous media, reasonable mathematical physical model is established and theoretical calculation is conducted. Density variation with temperature is used to study influence of the water natural convection on the freezing process. Calculation finds that effect of natural convection on the temperature distribution is achieved mainly through circulation of natural convection. The ice shape is achieved mainly by the microcirculation near the icing region. Both the ice storage system with wire and the one without wire appear the shape of inverted pear. Due to the wire, the shape of inverted pear is less clear than the ice storage system without wire.%盘管式蓄冰传热瓶颈出现在冰层处,考虑在管外加入一些金属丝来促进管外换热从而提高蓄冰效率.为了描述管外扩展表面给结冰过程带来的影响,把管外金属丝和水的混合区域考虑为多孔介质区域,建立了合理的数学物理模型,进行了理论计算,并采用了密度随温度接近抛物线变化来研究水的自然对流对结冰过程的影响.通过计算,发现自然对流对温度分布的影响主要通过自然对流大循环来实现的,但对结冰形状的影响主要是通过在结冰区域附近的微循环来实现的.加丝蓄冰系统与不加丝蓄冰系统结冰形状均呈倒梨形.但加丝系统因为丝网的存在,倒梨形状不如不加丝系统明显.

  5. 长水平段连续管钻塞过程的软件模拟应用∗%Software Simulation of Plug Drilling by Coiled Tubing in Long Horizontal Section

    Institute of Scientific and Technical Information of China (English)

    辛永安; 盖志亮; 吕维平; 朱峰; 费节高; 金志雄

    2016-01-01

    As long horizontal well multistage fracturing is still the main means of shale gas development, when the horizontal section length exceed 1 500 m, effectively coiled tubing operation and milling is one of the main challenges of the field operation�Software simulation is the key technology to guide the field staff to address the problem�Taking actual well operation as case study, the applications of software simulation in several key aspects have been introduced�Simulation results show that: ①hydraulic oscillator could extend the reach of coiled tubing;②using hydraulic oscillator, 3�75 kN WOB could be applied on the bridge plug at depth of 4 455 m, and the milling operation could be done by coiled tubing; ③the relationship between the surface weight difference and WOB could be used to precisely control WOB, helping successful milling operation; ④regression analysis showed that the friction coefficient of tripping down and up coiled tubing at the operating block were 0�26 and 0�23 respec⁃tively, and the simulation results and actual data matched well.%长水平井多级压裂依然是页岩气开发的主要手段,水平段长度超过1500 m以后,如何有效地实施连续管钻磨作业是现场施工的主要难题之一,软件模拟是指导现场人员解决这一难题的关键技术。结合现场施工的实际井例,介绍软件模拟在几个关键环节的应用。模拟分析结果表明:①使用水力振荡器可延长连续管在本井的作业深度;②使用水力振荡器可在4455 m处的桥塞施加3750 N以上的钻压,能用连续管完成该井的钻磨作业;③利用地面悬重差与钻压的关系可精确控制钻压,成功完成钻磨作业;④回归分析表明,该区块连续管下入和起出过程的摩擦因数分别为0�26和0�23的模拟计算结果与实际作业数据非常接近。研究结果对于长水平段连续管钻塞现场施工具有一定的参考作用。

  6. 水平管内纯饱和蒸汽强制对流冷凝局部换热特性%Local heat transfer characteristics of saturated steam forced convection condensation inside horizontal tube

    Institute of Scientific and Technical Information of China (English)

    徐慧强; 孙中宁; 谷海峰; 李昊

    2015-01-01

    通过对水平管内饱和纯蒸汽强制对流冷凝换热的实验研究,分析在管内两相流型为环状流-半环状与波状流时,质量含汽率、蒸汽入口流速和压力对蒸汽冷凝换热的影响,并得到了同时适用于这两种流型的计算局部冷凝传热系数的经验关联式。结果表明:局部冷凝传热系数在环状流-半环状流及波状流下均随质量含汽率和压力的降低而减小;在环状流-半环状流下,随蒸汽入口流速的升高而增大,在波状流下,随蒸汽入口流速的增大而减小;实验拟合所得到的换热经验关联式与实验结果符合良好,偏差在±20%以内。%An experimental investigation on forced convection condensation of saturated steam inside a horizontal tube was performed. The influences of steam quality, inlet steam velocity, and inlet steam pressure on condensation heat transfer were analyzed for annular-semiannular and wavy flows. A correlation for the local heat transfer coefficient of saturated steam condensation along a horizontal tube for both annular-semiannular and wavy flows was developed. For both annular-semiannular and wavy flows, local heat transfer coefficient decreased with steam quality and steam pressure. However, local heat transfer coefficient increased with inlet steam velocity for annular-semiannular flow while decreased with inlet steam velocity for wavy flow. The new correlation showed good agreement with experimental results with an error of 20% between calculated and experimental results.

  7. 中高温水平管降膜蒸发海水淡化研究%Research on Horizontal Tube Falling Film Evaporation for Seawater Desalination under Medium/High Temperature Conditions

    Institute of Scientific and Technical Information of China (English)

    于开录; 吕庆春; 谢峰; 阮国岭; 朱春来; 李海平

    2011-01-01

    Aimed at the disadvantages of low heat transfer coefficient and high water production cost in low temperature multi-effect distillation seawater desalination, the horizontal tube falling film evaporation for seawater desalination under medium/high temperature conditions was studied.The influence of seawater evaporation temperature, seawater spray load and heat transfer temperature difference on heat transfer performance and scale formation was investigated.It is found that the increasing of seawater evaporation temperature and the decreasing of heat transfer temperature difference can increase the heat transfer coefficient of seawater desalination.The insufficiency and inhomogeneity of seawater spray amount are the main reasons causing scale formation on horizontal heat exchange tubes.The scale products are mainly calcium carbonate which can be chemically removed, as well as a little calcium sulfate which can only be produced at 90 ℃.%针对低温多效蒸馏海水淡化技术存在传热系数低、制水成本相对较高等缺点,开展了中高温条件下水平管降膜蒸发海水淡化的研究,考察了海水蒸发温度、海水喷淋负荷和传热温差等因素对海水淡化过程中传热性能和结垢情况的影响.结果表明,提高海水蒸发温度、降低传热温差可以增大海水淡化传热系数;海水喷淋量不足和不均是导致换热管结垢的主要原因,结垢产物主要为可化学清洗的碳酸钙,在蒸发温度为90℃时还产生了少量的硫酸钙.

  8. Appliance & Analysis of Enhanced Pool Boiling Heat Transfer for Horizontal Tube in Water Jacket Heater%水平管强化池沸腾传热在水套炉中的应用分析

    Institute of Scientific and Technical Information of China (English)

    苏海鹏

    2011-01-01

    油气集输换热设备中,更多关注的是强化对流传热的研究和应用,而对于管外强化沸腾换热关注较少。在介绍池沸腾传热相关理论一般性原理的基础上,分析了影响池沸腾传热的主要因素。通过改良换热管外表面结构型式,在换热管表面形成凹凸或多孔的结构,这种结构下沸腾传热提高了一个数量级。选择合适的外界压力能够强化管外沸腾传热,提高了管外换热系数。最后讨论了池沸腾传热计算的有关问题。%The convection heat transfer enhancement were researched and applied widely on heat exchange equipment in oil - gas gathering and transportation. Based on the general principles of pool boiling heat transfer theory, the main influenced factors to pool boiling were analyzed. The outside wall of tube was changed to make it concave - convex or porous surface, the pool boiling heat transfer was enhanced by an order of magnitude. Correct design pressure could make the pool boiling enhancing and improving the heat transfer coefficient outside horizontal tube. Finally, the pool boiling heat transfer calculation was discussed.

  9. Experimental study on in-tube condensation heat transfer characteristics of helically coiled spiral tubes

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.U. [Sunchon First College, Sunchon (Korea); Kweon, Y.C. [Sun Moon University, Chonan (Korea); Han, K.I. [Pukyong National University, Pusan (Korea)

    2001-12-01

    An experimental study on condensation heat transfer characteristics of helically coiled spiral tubes was performed. The refrigerant is R-113. A refrigerant loop was established to measure the condensation heat transfer coefficients. Experiments were carried out uniform heat flux of 15 kW/m{sup 2}, refrigerant quality of 0.1 {approx} 0.9, curvature ratio of 0.016, 0.025 and 0.045. The curvature of a coil was defined as the ratio of the inside diameter of the tube to the diameter of the bending circle. To compare the condensation heat transfer coefficients of coiled spiral tubes, the previous results on coiled plain tubes and straight plain tubes were used. The results shows that the condensation heat transfer coefficients of coiled spiral tubes largely increase, as increasing Re and quality, compared to those of coiled plain tubes and straight plain tubes. As increasing degree of subcooling, however, the condensation heat transfer coefficients on coiled spiral tubes decrease. It is found that the heat transfer enhancement is more better than coiled plain tubes and straight plain tubes, as increasing curvature ratio. (author). 13 refs., 10 figs., 1 tab.

  10. Experimental investigation of flow boiling heat transfer and pressure drops characteristic of R1234ze(E, R600a, and a mixture of R1234ze(E/R32 in a horizontal smooth tube

    Directory of Open Access Journals (Sweden)

    Jinyou Qiu

    2015-09-01

    Full Text Available The saturated flow boiling heat transfer coefficients and frictional pressure drops characteristics of R1234ze(E, R600a, and L-41b (R1234ze(E/R32 (27/73 mass % inside an 8 mm inner diameter horizontal tube were investigated. The experiment was carried out at the saturation temperature of 20°C with heat flux ranging from 5.0 to 10.0 kW·m−2 and mass flux ranging from 200 to 400 kg·m−2·s−1. The influence of mass flux, heat flux, and quality on the heat transfer coefficients and frictional pressure drops were examined and discussed. The results show that the local heat transfer coefficients of R1234ze(E are averagely 33% and 18% lower than those of R600a and L-41b, respectively. The frictional pressure drops of R1234ze(E are 21% lower than those of R600a but 6% greater than those of L-41b. Meanwhile, the experimental data of local heat transfer coefficients and frictional pressure drops are compared with some well-known correlations available in literatures.

  11. Plains Traveler

    Science.gov (United States)

    2006-01-01

    10 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dust devil traveling across a plain west-southwest of Schiaparelli Crater, in far eastern Sinus Meridiani. The dust devil is casting a shadow toward the northeast, just south (below) of an egg-shaped crater. Location near: 6.4oS, 349.3oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Summer

  12. Utopia Plain

    Science.gov (United States)

    2006-01-01

    5 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dark-toned, cratered plain in southwest Utopia Planitia. Large, light-toned, windblown ripples reside on the floors of many of the depressions in the scene, including a long, linear, trough. Location near: 30.3oN, 255.3oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  13. Revisiting Plain Language.

    Science.gov (United States)

    Mazur, Beth

    2000-01-01

    Discusses the plain language movement and its origins. Reviews past and current resources related to plain language writing. Examines criticism of the movement while examining past and current plain language literature, with particular attention to the information design field. (SR)

  14. Ear Tubes

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Ear Tubes Ear Tubes Patient Health Information News media ... and throat specialist) may be considered. What are ear tubes? Ear tubes are tiny cylinders placed through ...

  15. Augmentation of Condensation Heat Transger by Finning of Tubes

    OpenAIRE

    1992-01-01

    This paper summarizes experimental and theoretical studies that have been performed in our laboratory to enhance condensation heat transfer on horizontal tubes and tube bundles by use of fins. Use of a drainge strip is proved to be very effective in further enhancing condensation heat transfer on the horizontal finned tube. Effects of fin geometry and tube arrangement on the condensation heat transfer performance of the tube bundle are investigated. A theoretical model is proposed to predict ...

  16. R32/R134a在水平内螺纹管内流动沸腾强化特性的分析与研究%Convective heat transfer of R32/R134a inside horizontal microfin tubes

    Institute of Scientific and Technical Information of China (English)

    吴志光; 马虎根; 蔡祖恢

    2005-01-01

    Experimental study was reported for flow boiling heat transfer of a nonazeotropic mixture of R32/R134a [25% (mass) /75% (mass)] inside both smooth and microfin tubes with internal spiral grooves. The influences of mass quality, heat flux & mass flow rate on Af (heat transfer enhanced coefficient) are discussed, respectively. The experimental results show that the microfin tubes have distinct performance advantages over the smooth tube at similar conditions, the varying of heat flux has the greatest effect on Af, and Af varied from 1.4-2.2.

  17. 水-酒精混合蒸气在水平圆管横截面换热特性的研究%Research on Condensation Heat Transfer Characteristics of Ethanol-water Vapor on Cross Section of Horizontal Tube

    Institute of Scientific and Technical Information of China (English)

    吴凡; 胡申华; 高策

    2014-01-01

    In this article the effects of vapor pressure, vapor concentration on the condensation heat transfer characteristics of ethanol-water mixture vapor on horizontal tube were investigated experimentally. Visual results were showed in this experiment. In order to clarify the heat transfer characteristics of vary ethanol vapor concentrations, heat flux and vapor-to-surface temperature difference were measured. The results demonstrate that the local heat transfer coefficients at different locations on condensing surface were different, and at the local position with greater tension gradient the heat transfer coefficient was higher. On the same condition of vapor concentration and speed, heat transfer coefficients of high pressure are bigger than those of low pressure in the low-ethanol concentration range. But the effect of vapor pressure on the heat transfer coefficients is not obvious in the high -ethanol concentration range. The reason for this is that bigger diffusion resistance and the gradient of the surface tension versus the condensation mass fraction becomes smaller with the increase in vapor concentration. It has been found that different concentration of ethanol in the liquid phase has significant influence on heat transfer coefficients on different cross section thermocouples. The D-value of heat transfer coefficients are greater when ethanol composition is 2% and 5%, and lower in other composition at different position in the same circumstance.%本文搭建了水平圆管管外凝结传热实验台,以水-酒精混合蒸气为工质,在不同蒸气压力和不同酒精浓度的条件下对水平圆管外凝结换热特性进行了研究,并实现了实验的可视化,分析了不同酒精浓度下造成凝结换热特性差异的原因。实验结果表明:凝结表面不同位置的传热系数不同,表面张力梯度大的位置凝结传热系数较大。在相同流速和浓度条件下,酒精浓度较低时凝结传热系数随蒸气压

  18. DKV joint project: reduction of CFC-emissions in air conditioning and refrigeration. Subproject 6. Pool boiling of new refrigerants and their mixtures at single plain and finned tubes. Final report; DKV-Verbundvorhaben: Minderung von FCKW-Emissionen in der Klima- und Kaeltetechnik. Teilvorhaben 6; Waermeuebergang bei der Verdampfung neuer Kaeltemittel an einzelnen Glatt- und Rippenrohren. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Gorenflo, D.; Rott, W.; Sokol, P.; Caplanis, S; Kuenstler, W.

    1993-03-01

    Heat transfer at pool boiling from three novel finned tubes with different fin geometry to the new refrigerants R134a (CH{sub 2}F.CF{sub 3}), R152a (CH{sub 3}.CHF{sub 2}), R227 (CF{sub 3}.CHF.CF{sub 3}) and to a nearly equimolar mixture of R134a and R152a has been investigated within extended ranges of heat flux and saturation pressure. The main new features of the tubes are: K-shaped fins with very narrow fin distances/T-shaped fins with additional grooves between the fins/Y-shaped fins with additional grooves between the fins. The results show that especially the tubes with T-shaped and Y-shaped fins are significantly superior to plain tubes at pool boiling of the new refrigerants at saturation pressures up to approximately 10 bar. The biggest enhancement has been achieved using the tube with Y-shaped fins, thus energy consumption can be reduced by smaller temperature differences on the pool side, if these tubes will be applied, and the amount of refrigerants as well as construction material for the evaporators can be reduced by more compact design, being possible, because the heat flow rate transferred per unit of tube length may be chosen higher. (orig.). 11 refs., 1 tab., 12 figs. [Deutsch] Durch Waermeuebergangsmessungen bei der Verdampfung von neuen, teilfluorierten Kaeltemitteln an neuentwickelten Hochleistungs-Verdampferrohren sollten verlaessliche Auslegungsgrundlagen fuer optimierte Rohrbuendelverdampfer bereitgestellt werden, die mit geringerem Energiebedarf und durch kompakte Bauweise mit reduziertem Material- und Kaeltemittelaufwand auskommen und dadurch einerseits kein Ozongefaehrdungspotential und andererseits einen geringeren Beitrag zum Treibhauseffket liefern als die z.Zt. noch verwendete Technik. Zu Beginn des Vorhabens existierten entsprechende Unterlagen in der Literatur nicht. Als Versuchsstoffe dienten die neuen Kaeltemittel R134a(CH{sub 2}F.CF{sub 3}), R152a(CH{sub 3}.CHF{sub 2}), R227(CF{sub 3}.CHF.CF{sub 3}) sowie ein etwa aequimolares

  19. Experimental study of the turbulent convective heat transfer of titanium oxide nanofluid flowing inside helically corrugated tubes

    Energy Technology Data Exchange (ETDEWEB)

    Salimpour, Mohammad Reza; Golmohammadi, Kia; Sedaghat, Ahmad [Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Campo, Antonio [The University of Texas at San Antonio, San Antonio (United States)

    2015-09-15

    The convective heat transfer for the turbulent flow of water/TiO{sub 2} nanofluid inside helically horizontal corrugated tubes is investigated in this paper using experimental techniques. The tube boundary condition is a uniform wall temperature. The test apparatus was designed and assembled with a test section containing 93 cm copper tubes with internal and external diameters of 7.71 mm and 9.52 mm, respectively. First, the heat transfer characteristics of the distilled water turbulent flow in a plain copper tube were measured preliminarily. Second, various test runs were performed for nanofluids with two nanoparticle concentrations (0.1% and 0.5%), two corrugation depth to diameter ratios (0.0648 and 0.103), two corrugation pitch to diameter ratios (0.917 and 1.297), and two corrugation width to diameter ratios (0.363 and 0.492) that were all within the range of turbulent Reynolds numbers (3000 < Re < 15000). The experimental results reveal that the Nusselt number augments the dual increments in corrugation depth and width and with the decrements in corrugation pitch, particularly for high Reynolds numbers. The nanoparticles have a stronger effect on the heat transfer in helically corrugated tubes with higher corrugation depths and widths as well as lower corrugation pitches. A correlation for the Nusselt number in terms of the helically corrugated tubes is introduced based on the linear regression analysis of the experimental data.

  20. Friction characteristics for water-ethylene glycol mixture flow in horizontal tubes with new type of helically fins%乙二醇溶液水平新型多头内螺纹管内流阻特性

    Institute of Scientific and Technical Information of China (English)

    张吉礼; 王永辉; 马志先; 陈敬东

    2016-01-01

    建立了水平管内绝热流动阻力特性试验系统,试验研究了乙二醇溶液在两种新型多头内螺纹管内的流动特性.试验中,乙二醇体积分数为15%,两种试验管公称内径为22 mm与16 mm、螺纹头数为60头与38头、螺旋升角为45°与60°、相对粗糙高为0.022与0.053,测试段长度分别为2643 mm与2945 mm,Pr范围13.9~23.2,Re范围4000~33000.结果表明:多头内螺纹管阻力系数达到极大值之前的变化趋势与均匀粗糙管显著不同,而且无法通过既有多头内螺纹管经验模型准确描述;多头内螺纹管内达到阻力系数极大值的分界点Re为内肋结构参数的函数;入口效应对内螺纹管阻力系数的影响随Re增加而增大,传统的判别入口段可忽略的判据(l/di>60)并不适用于多头内螺纹管,尤其是在Re>20000的工况;既有多头内螺纹管经验模型适用工况条件有待进一步拓宽,多头内螺纹结构流动阻力的作用机制、阻力系数出现极大值的分界点的变化规律有待进一步试验探索.%An experiment setup was built for investigating single-phase adiabatic flow characteristics of internal helical-rib roughness. The friction characteristics for 15% (by volume) water-ethylene glycol mixture flow in three internal finned tubes (two types of new developed internal helical-fins) and a smooth tube were obtained. The parameters of test tubes are nominal inside diameters (22 mm and 16 mm), numbers of fins (60 and 38), helix angles (45° and 60°) and fin height to inside diameter ratios (0.022 and 0.053). The lengths of the internal helical-rib tubes in test section were 2643 mm and 2945 mm, respectively. The Prandtl number varied from 13.9 to 23.2 and the Reynolds number ranged from 4000 to 33000. The smooth-tube results were compared to the Filonenko equation with satisfactory agreement. The experimental results of different length and same type multi-start internal helically-finned tubes also showed that the

  1. Experimental investigation into effects of ultrasonic vibration on pool boiling heat transfer performance of horizontal low-finned U-tube in TiO2/R141b nanofluid

    Science.gov (United States)

    Chang, Tong-Bou; Wang, Zi-Long

    2016-11-01

    An experimental investigation was performed into the pool boiling heat transfer performance of a low-finned U-tube immersed in TiO2/R141b nanofluid with four different nanoparticle loadings (0, 0.0001, 0.001, and 0.01 vol%). The energy-dispersive X-ray spectrometry results revealed that some of the TiO2 nanoparticles adhered to the heated surface during boiling, and therefore increased the thermal resistance. The heat transfer performance of the nanofluids with particle loadings of 0.0001, 0.001 and 0.01 vol% was thus found to be reduced by around 10, 20 and 50 %, respectively, compared to that of pure R141b refrigerant. Accordingly, an ultrasonic vibration crusher was used to inhibit the formation of the TiO2 nano-sorption layer on the U-tube surface. The ultrasonic vibration suppressed the deposition of TiO2 nanoparticles and improved the heat transfer performance of the nanofluids as a result. Of the four working fluids, the nanofluid with a particle loading of 0.0001 vol% yielded the optimal heat transfer performance (i.e., a heat transfer coefficient around 30 % higher than that of pure R141b refrigerant.)

  2. Tracheostomy tubes.

    Science.gov (United States)

    Hess, Dean R; Altobelli, Neila P

    2014-06-01

    Tracheostomy tubes are used to administer positive-pressure ventilation, to provide a patent airway, and to provide access to the lower respiratory tract for airway clearance. They are available in a variety of sizes and styles from several manufacturers. The dimensions of tracheostomy tubes are given by their inner diameter, outer diameter, length, and curvature. Differences in dimensions between tubes with the same inner diameter from different manufacturers are not commonly appreciated but may have important clinical implications. Tracheostomy tubes can be cuffed or uncuffed and may be fenestrated. Some tracheostomy tubes are designed with an inner cannula. It is important for clinicians caring for patients with a tracheostomy tube to appreciate the nuances of various tracheostomy tube designs and to select a tube that appropriately fits the patient. The optimal frequency of changing a chronic tracheostomy tube is controversial. Specialized teams may be useful in managing patients with a tracheostomy. Speech can be facilitated with a speaking valve in patients with a tracheostomy tube who are breathing spontaneously. In mechanically ventilated patients with a tracheostomy, a talking tracheostomy tube, a deflated cuff technique with a speaking valve, or a deflated cuff technique without a speaking valve can be used to facilitate speech. Copyright © 2014 by Daedalus Enterprises.

  3. 酒精-水混合蒸气在水平管外凝结换热的实验研究%Experimental research of condensation heat transfer of ethanol-water vapor outside horizontal tube

    Institute of Scientific and Technical Information of China (English)

    乔宏斌; 王顺; 胡申华

    2016-01-01

    在压力分别为31.16 kPa和47.5 kPa下,进行了酒精气相质量分数为0%、1%、5%,10%的凝结换热实验并观测了凝结形态,混合蒸气的质量流量为10 kg/h 和14 kg/h,实验圆管长度为150 mm,外径为16 mm,壁厚为3 mm,管外的换热系数通过 Gnielinski关联式计算.实验研究发现,混合蒸气的凝结形态为珠状凝结,混合蒸气的换热系数比同样实验条件的纯水蒸气都有不同程度的提高,尤其是1%浓度的混合蒸气.随着质量流量和压力的增大,换热系数有所提高,在当前的流量变化范围内,压力的影响更大一些.%An experimental loop has been established to measure the condensation heat transfer coefficient of ethanol-water mixed vapor in a tube,the pressures are 31.16 kPa and 47.16 kPa,the mass concentrations of ethanol vapor phase are 0%,1%,5% and 10%,vapor mass flux is 10 kg/h or 14 kg/h.The experimental tube has a length of 1 500 mm,outer diameter of 16 mm and a wall thickness of 3 mm.The heat transfer coefficient of outside of tube is acquired by Gnielinski correlation.The experiment shows that dropwise mode would appear mixed vapor condensing,for different concentration vapor,heat transfer coefficient increased in various degrees,especially for 1%.The HTC also increased a little with increase of mass flux and pressure,and the effect of pressure on HTC is greater compared to mass flux.

  4. Effect of tube-support interaction on the dynamic responses of heat exchanger tubes. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Y.S.; Jendrzejczyk, J.A.; Wambsganss, M.W.

    1977-01-01

    Operating heat exchangers have experienced tube damages due to excessive flow-induced vibration. The relatively small inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the tube vibrational characteristics. In attempting a theoretical analysis, questions arise as to the effects of tube-baffle impacting on dynamic responses. Experiments were performed to determine the effects of tube-baffle impacting in vertical/horizontal tube orientation, and in air/water medium on the vibrational characteristics (resonant frequencies, mode shapes, and damping) and displacement response amplitudes of a seven-span tube model. The tube and support conditions were prototypic, and overall length approximately one-third that of a straight tube segment of the steam generator designed for the CRBR. The test results were compared with the analytical results based on the multispan beam with ''knife-edge'' supports.

  5. Effect of Uniformly and Nonuniformly Coated Al2O3 Nanoparticles over Glass Tube Heater on Pool Boiling

    Directory of Open Access Journals (Sweden)

    Nitin Doifode

    2016-01-01

    Full Text Available Effect of uniformly and nonuniformly coated Al2O3 nanoparticles over plain glass tube heater on pool boiling heat transfer was studied experimentally. A borosilicate glass tube coated with Al2O3 nanoparticle was used as test heater. The boiling behaviour was studied by using high speed camera. Result obtained for pool boiling shows enhancement in heat transfer for nanoparticle coated surface heater and compared with plain glass tube heater. Also heat transfer coefficient for nonuniformly coated nanoparticles was studied and compared with uniformly coated and plain glass tube. Coating effect of nanoparticles over glass tube increases its surface roughness and thereby creates more nucleation sites.

  6. The Plains of Venus

    Science.gov (United States)

    Sharpton, V. L.

    2013-12-01

    Volcanic plains units of various types comprise at least 80% of the surface of Venus. Though devoid of topographic splendor and, therefore often overlooked, these plains units house a spectacular array of volcanic, tectonic, and impact features. Here I propose that the plains hold the keys to understanding the resurfacing history of Venus and resolving the global stratigraphy debate. The quasi-random distribution of impact craters and the small number that have been conspicuously modified from the outside by plains-forming volcanism have led some to propose that Venus was catastrophically resurfaced around 725×375 Ma with little volcanism since. Challenges, however, hinge on interpretations of certain morphological characteristics of impact craters: For instance, Venusian impact craters exhibit either radar dark (smooth) floor deposits or bright, blocky floors. Bright floor craters (BFC) are typically 100-400 m deeper than dark floor craters (DFC). Furthermore, all 58 impact craters with ephemeral bright ejecta rays and/or distal parabolic ejecta patterns have bright floor deposits. This suggests that BFCs are younger, on average, than DFCs. These observations suggest that DFCs could be partially filled with lava during plains emplacement and, therefore, are not strictly younger than the plains units as widely held. Because the DFC group comprises ~80% of the total crater population on Venus the recalculated emplacement age of the plains would be ~145 Ma if DFCs are indeed volcanically modified during plains formation. Improved image and topographic data are required to measure stratigraphic and morphometric relationships and resolve this issue. Plains units are also home to an abundant and diverse set of volcanic features including steep-sided domes, shield fields, isolated volcanoes, collapse features and lava channels, some of which extend for 1000s of kilometers. The inferred viscosity range of plains-forming lavas, therefore, is immense, ranging from the

  7. Heat transfer during boiling at finned tubes and finned tube bundles; Der Waermeuebergang beim Sieden an Rippenrohren und Rippenrohrbuendeln

    Energy Technology Data Exchange (ETDEWEB)

    Chen Qiurong

    1991-06-10

    Based on bubble dynamics at single tubes and hydrodynamics at multi-tube arrangements (a vertical tube row, tube bundle), a theory for calculation of heat transfer at single tubes, at a vertical tube row and at tube bundles was developed. The theory applies both to finned tubes and plain tubes. To verify the presented theory, measured heat transfer coefficients taken from literature are recalculated. A comparison between heat transfer coefficients for single tubes and two-tube arrangements, calculated according to the theory and determined by measurements shows good agreement. Measuring results for plain tube bundles and bundles of finned tubes also agree well with the theory. (orig./MM) [Deutsch] Aufbauend auf der Blasendynamik an Einzelrohren und der Hydrodynamik in Mehrrohranordnungen (eine senkrechte Rohrreihe, Rohrbuendel) wurde eine Theorie zur Berechnung des Waermeuebergangs an Einzelrohren, an einer senkrechten Rohrreihe und an Rohrbuendeln entwickelt. Die Theorie gilt sowohl fuer Rippenrohre als auch fuer Glattrohre. Zur Ueberpruefung der vorgestellten Theorie werden gemessene Waermeuebergangskoeffizienten aus der Literatur nachgerechnet. Ein Vergleich zwischen den nach der Theorie berechneten und den aus Messungen ermittelten Waermeuebergangskoeffizienten fuer Einzelrohre und Zweirohranordnungen zeigt gute Uebereinstimmung. Auch die Messergebnisse von Glattrohrbuendeln und von Buendeln mit den Rippenrohren lassen sich durch die Theorie gut wiedergeben. (orig./MM)

  8. Tube erosion in bubbling fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Levy, E.K. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center; Stallings, J.W. [Electric Power Research Inst., Palo Alto, CA (United States)

    1991-12-31

    This paper reports on experimental and theoretical studies that were preformed of the interaction between bubbles and tubes and tube erosion in fluidized beds. The results are applicable to the erosion of horizontal tubes in the bottom row of a tube bundle in a bubbling bed. Cold model experimental data show that erosion is caused by the impact of bubble wakes on the tubes, with the rate of erosion increasing with the velocity of wake impact with the particle size. Wake impacts resulting from the vertical coalescence of pairs of bubbles directly beneath the tube result in particularly high rates of erosion damage. Theoretical results from a computer simulation of bubbling and erosion show very strong effects of the bed geometry and bubbling conditions on computed rates of erosion. These results show, for example, that the rate of erosion can be very sensitive to the vertical location of the bottom row of tubes with respect to the distributor.

  9. Horizontal drilling in Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Sidey, P.; Precul, L. [Sproule Associates Ltd., Calgary, AB (Canada)

    2002-07-01

    A review of oil and gas production in Ontario was presented with particular reference to drilling activity between 1987 to mid 2002 when 1450 vertical wells were drilled, of which 1100 were for petroleum production and the remainder were for gas storage, observation wells, private gas wells and stratigraphic tests. Of the 1100 vertical wells drilled for petroleum production, 40 per cent became gas wells, 16 per cent became oil wells, 4 per cent became oil and gas wells, and 40 per cent were dry. During the same time period, 133 horizontal wells were also drilled, mostly for petroleum. The most active operator was Talisman Energy, which drilled 101 of the 133 horizontal wells. The remainder were drilled by 12 other companies. Of the horizontal wells, 64 per cent became oil wells, 19 per cent became gas wells, and 17 per cent were dry. This presentation included graphs depicting which oil and gas pools saw vertical or horizontal drilling during the designated time period, and explained how the wells were classified. Both horizontal and vertical well targets were illustrated. Particular reference was made to Talisman Energy's Lake Erie Drilling program which revealed that horizontal wells have an initial production rate that is 5 times that expected from vertical wells. The Hillman Pool case study revealed that the initial rate of the average horizontal well is less than half that of the average vertical well. Horizontal drilling in the Lake Erie Morpeth Gas pool has also been a commercial success. This paper demonstrates that operators have maintained Ontario's oil and gas production at high levels. In 1997 widespread horizontal drilling began taking place in Ontario, and since then, approximately 30 per cent of the wells drilled in the province have been horizontal. 16 figs.

  10. Utility of Lava Tubes on Other Worlds

    Science.gov (United States)

    Walden, Bryce E.; Billings, T. L.; York, Cheryl Lynn; Gillett, S. L.; Herbert, M. V.

    1998-01-01

    On Mars, as on Earth, lava tubes are found in the extensive lava fields associated with shield volcanism. Lunar lava-tube traces are located near mare-highland boundaries, giving access to a variety of minerals and other resources, including steep slopes, prominent heights for local area communications and observation, large-surface areas in shade, and abundant basalt plains suitable for landing sites, mass-drivers, surface transportation, regolith harvesting, and other uses. Methods for detecting lava tubes include visual observations of collapse trenches and skylights, ground-penetrating radar, gravimetry, magnetometry, seismography, atmospheric effects, laser, lidar, infrared, and human or robotic exploration.

  11. Effect of evaporation temperature on boiling heat transfer in horizontal ribbed and embossing finned tube pool%蒸发温度对水平正反齿压花齿型肋管池沸腾换热的影响

    Institute of Scientific and Technical Information of China (English)

    张吉礼; 陈敬东; 马志先; 王永辉

    2016-01-01

    随着节能减排的大力推广,管外沸腾强化传热技术得到了广泛的研究和发展。设计建立了水平双侧强化管管外沸腾试验系统,以R134a为循环工质试验研究了不同热通量工况下,蒸发温度对正反齿压花齿型三维肋管池沸腾换热特性影响,并结合试验结果分析探讨了其理论描述方法。结果表明:蒸发传热系数随蒸发温度变化趋势线的斜率随热通量呈现非线性变化;在同一蒸发温度下,管表面传热系数均随热通量单调递增,但增长率随热通量增加而逐步降低;回归分析获得不同热通量下蒸发温度对正反齿压花齿型蒸发管表面传热系数影响的统一表达式;等热通量工况强化传热因子在热通量超过10 kW·m−2后升至2以上,在热通量接近20 kW·m−2时达到极大值2.588,但在热通量接近5 kW·m−2时接近1;蒸发温度及其与热通量合同对正反齿压花齿型蒸发管表面传热系数的作用机理与理论描述方法有待进一步深入研究。%Under a promotion of energy conservation and emission reduction, efforts on research and development of the technologies related to boiling heat transfer enhancement of outer tube have been conducted extensively. In this article, a testing system for boiling heat transfer outside the horizontal double-side enhanced tubes was established. Using R134a as a cyclic working medium, the effect of evaporation temperature on the characteristics of boiling heat transfer in three-dimensional ribbed and embossing finned tube under conditions of varied heat flux was investigated, on basis of which theoretical descriptive method was discussed. It showed that , the curve slope of evaporation heat transfer coefficient as a function of evaporation temperature is non-linearly related to the heat flux. At the same evaporation temperature, it shows a monotonic increase in the heat transfer coefficient on tube surface with the heat flux

  12. 振动流化床与浸没水平管平均传热特性理论分析与实验研究%Theoretical prediction and experimental investigation on the average heat transfer characteristic between vibrated fluidized beds and horizontal tubes

    Institute of Scientific and Technical Information of China (English)

    朱学军; 邓俊

    2012-01-01

    在二维流化床( 240mm×80mm)中,以平均粒径dp为1.83mm的玻璃珠为物料,研究了振动流化床与浸没水平管间传热规律;考察了流化数、振动频率、床高、水平管管径等因素对平均传热系数的影响.采用自制探头对浸没加热管束和振动流化床层间平均传热系数进行实验测定,利用颗粒团模型,建立了振动流化床层与浸没水平管间平均传热模型,并对平均传热系数的理论预测值与实验测定值进行了比较.结果表明:计算值与实验值吻合较好,误差在±15%范围内.在较高流化数、低振动频率时,实验值处于理论值上方;随着振动频率、管径增大,平均传热系数实验值逐渐趋于理论预测值甚至低于理论预测值.结果可为带浸没水平管的振动流化床设计和研究提供参考.%Experiments using the glass beads with the average diameter dp of 1.83mm was conducted in a two-dimensional vibrated fluidized bed. The average heat transfer laws have been investigated. The effect of the fluidization numbers, vibration frequency, static bed height, and the tube diameter on the average heat transfer coefficient have been analyzed. The average heat transfer coefficients was experimentally investigated with self-made probe. A mathematical model is proposed to predict the average heat transfer coefficients between vibrated flu— idized bed and immersed horizontal tubes based on the particle packets renewal theory. The results show that the values of theoretical prediction are in good agreement with experimental data, and the error is inrange of ±15%. The values of experimental above the theoretical prediction at the higher fluidization numbers and lower vibration frequency. They are consistent with each other and even lower than theoretical prediction with increasing vibration frequency and tube diamete. The results can provide references for future designing and researching on the vibrated fluidized beds with

  13. Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube

    Energy Technology Data Exchange (ETDEWEB)

    Bucholz, J.A.

    2000-07-01

    The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source.

  14. Convection heat transfer and pressure drop in cross flow over finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Baran, M.; Pronobis, M.

    1984-05-15

    This paper reports the results of an experimental study on the heat transfer and pressure drop in finned tube banks. The measurements were carried out for the tubes with fins arranged parallel and a certain angle to the flow direction. The performance of such a heat exchanger with that of the conventional one i.e. plain tube heat exchanger, is compared.

  15. Estudio del horizonte local

    OpenAIRE

    Ros Ferré, Rosa Maria

    2009-01-01

    El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical).

  16. Gastrostomy Tube (G-Tube)

    Science.gov (United States)

    ... the recovery room, sometimes called the "post-op" (post-operative) room or PACU (post-anesthesia care unit), and ... site; discharge that's yellow, green, or foul-smelling; fever) excessive bleeding or drainage from the tube site ...

  17. Computational fluid dynamics analysis on heat transfer and friction factor characteristics of a turbulent flow for internally grooved tubes

    Directory of Open Access Journals (Sweden)

    Selvaraj P.

    2013-01-01

    Full Text Available The article presents computational fluid dynamics studies on heat transfer, pressure drop, friction factor, Nusselt number and thermal hydraulic performance of a plain tube and tube equipped with the three types of internal grooves (circular, square and trapezoidal.Water was used as the working fluid. Tests were performed for Reynolds number ranges from 5000 to 13500 for plain tube and different geometry inside grooved tubes. The maximum increase of pressure drop was obtained from numerical modeling 74% for circular, 38% for square and 78% for trapezoidal grooved tubes were compared with plain tube. Based on computational fluid dynamics analysis the average Nusselt number was increased up to 37%, 26% and 42% for circular, square and trapezoidal grooved tubes respectively while compared with the plain tube. The thermal hydraulic performance was obtained from computational fluid dynamics analysis up to 38% for circular grooved tube, 27% for square grooved tube and 40% for trapezoidal grooved tube while compared with the plain tube.

  18. Development boiling to sprinkled tube bundle

    Directory of Open Access Journals (Sweden)

    Kracík Petr

    2016-01-01

    Full Text Available This paper presents results of a studied heat transfer coefficient at the surface of a sprinkled tube bundle where boiling occurs. Research in the area of sprinkled exchangers can be divided into two major parts. The first part is research on heat transfer and determination of the heat transfer coefficient at sprinkled tube bundles for various liquids, whether boiling or not. The second part is testing of sprinkle modes for various tube diameters, tube pitches and tube materials and determination of individual modes’ interface. All results published so far for water as the falling film liquid apply to one to three tubes for which the mentioned relations studied are determined in rigid laboratory conditions defined strictly in advance. The sprinkled tubes were not viewed from the operational perspective where there are more tubes and various modes may occur in different parts with various heat transfer values. The article focuses on these processes. The tube is located in a low-pressure chamber where vacuum is generated using an exhauster via ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another.

  19. Development boiling to sprinkled tube bundle

    Science.gov (United States)

    Kracík, Petr; Pospíšil, Jiří

    2016-03-01

    This paper presents results of a studied heat transfer coefficient at the surface of a sprinkled tube bundle where boiling occurs. Research in the area of sprinkled exchangers can be divided into two major parts. The first part is research on heat transfer and determination of the heat transfer coefficient at sprinkled tube bundles for various liquids, whether boiling or not. The second part is testing of sprinkle modes for various tube diameters, tube pitches and tube materials and determination of individual modes' interface. All results published so far for water as the falling film liquid apply to one to three tubes for which the mentioned relations studied are determined in rigid laboratory conditions defined strictly in advance. The sprinkled tubes were not viewed from the operational perspective where there are more tubes and various modes may occur in different parts with various heat transfer values. The article focuses on these processes. The tube is located in a low-pressure chamber where vacuum is generated using an exhauster via ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another.

  20. Mountain-Plains Curriculum.

    Science.gov (United States)

    Mountain-Plains Education and Economic Development Program, Inc., Glasgow AFB, MT.

    The document lists the Mountain-Plains curriculum by job title (where applicable), including support courses. The curriculum areas covered are mathematics skills, communication skills, office education, lodging services, food services, marketing and distribution, welding support, automotive, small engines, career guidance, World of Work, health…

  1. Sliding Downhill Horizontally

    Science.gov (United States)

    Zurcher, Ulrich

    2005-04-01

    We study the motion of object sliding on a rough incline plane. The coefficient of kinetic friction between the surface and the object is such that the magnitude of the gravitational force along the incline F is equal to the magnitude of the kinetic friction S. If the initial velocity of the object is along the incline, the object slides down the incline with constant velocity. We study the case when the object in launched in horizontal direction. We derive exact expressions for the terminal speed of the object and the maximum horizontal displacement of the object.

  2. Coolant rate distribution in horizontal steam generator under natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Blagovechtchenski, A.; Leontieva, V.; Mitrioukhin, A. [St. Petersburg State Technical Univ. (Russian Federation)

    1997-12-31

    In the presentation the major factors determining the conditions of NCC (Natural Coolant Circulation) in the primary circuit and in particular conditions of coolant rate distribution on the horizontal tubes of PGV-1000 in NPP with VVER-1000 under NCC are considered. 5 refs.

  3. Influence of furnace tube shapeon thermal strain of fire-tube boilers

    Directory of Open Access Journals (Sweden)

    Gaćeša Branka

    2014-01-01

    Full Text Available The aim of this paper is to use numerical analysis and fine element method-FEM to investigate the influence of furnace tube shape on the thermal strain of fire-tube boilers. Thermal stresses in corrugated furnace tubes of different shape, i.e. with different corrugation pitch and depth, were analysed first. It was demonstrated that the thermal stresses in corrugated furnace tube are significantly reduced with the increase of corrugation depth. Than deformations and stresses in the structure of a fire-tube boiler were analysed in a real operating condition, for the cases of installed plain furnace tube and corrugated furnace tubes with different shapes. It was concluded that in this fire-tube boiler, which is of larger steam capacity, the corrugated furnace tube must be installed, as well as that the maximal stress in the construction is reduced by the installation of the furnace tube with greater corrugation depth. The analysis of stresses due to pressure and thermal loads pointed out that thermal stresses are not lower-order stresses in comparison to stresses due to pressure loads, so they must be taken into consideration for boiler strength analysis. [Projekat Ministarstva nauke Republike Srbije, br. TR 35040 i br. TR 35011

  4. Filmwise Condensation of Steam on Externally-Finned Horizontal Tubes.

    Science.gov (United States)

    1983-12-01

    heat- transfer coefficient using the Sieder -Tate equation. The leading coefficient for this equation was found to be 0.034 ± 0.001, and was used to...36 A. PROGRAM SIEDER . . . . . . . . . . . . . . . . 36 B. PROGRAM WILSON . ........... .... 36 C. PROGRAM DEP...coeffizient, W/M 2-K X Parameter, D -- / /Zk,. Y Parameter, . 1/3[ 1/U. - R,,] z Sieder -Tate parameter. ReO-8Pr1/3Gs/&,)O.I Q Expansion coefficient of

  5. Horizontal Connection and Horizontal Mean Curvature in Carnot Groups

    Institute of Scientific and Technical Information of China (English)

    Kang Hai TAN; Xiao Ping YANG

    2006-01-01

    In this paper we give a geometric interpretation of the notion of the horizontal mean curvature which is introduced by Danielli-Garofalo-Nhieu and Pauls who recently introduced sub-Riemannian minimal surfaces in Carnot groups. This will be done by introducing a natural nonholonomic connection which is the restriction (projection) of the natural Riemannian connection on the horizontal bundle. For this nonholonomic connection and (intrinsic) regular hypersurfaces we introduce the notions of the horizontal second fundamental form and the horizontal shape operator. It turns out that the horizontal mean curvature is the trace of the horizontal shape operator.

  6. Some aspects of film condensation of steam on finned tubes

    OpenAIRE

    Coumes, James M.

    1989-01-01

    Approved for public release; distribution is unlimited Heat-transfer measurements were made for filmwise condensation of steam on smooth tubes and finned tubes with rectangular-shaped fins. The influence of fin root diameter on a single horizontal finned tube was examined by taking data for two families of tubes whose fin root diameters were 12.7 and 19.05 mm. Each family of tubes had fins that were 1 mm thick and 1 mm high but with fin spacings of 0.25, 0.50, 1.0, 1.5, 2.0, and 4.0 mm. ...

  7. Chest tube insertion

    Science.gov (United States)

    ... tube insertion; Insertion of tube into chest; Tube thoracostomy; Pericardial drain ... Kirsch TD, Sax J. Tube thoracostomy. In: Roberts JR, ed. Roberts and ... . 6th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 10.

  8. Jejunostomy feeding tube

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000181.htm Jejunostomy feeding tube To use the sharing features on this ... vomiting Your child's stomach is bloated Alternate Names Feeding - jejunostomy tube; G-J tube; J-tube; Jejunum ...

  9. Horizontally mounted solar collector

    Science.gov (United States)

    Black, D. H. (Inventor)

    1979-01-01

    Solar energy is collected by using a vertical deflector assembly, a stationary reflector and a horizontally mounted solar collector. The deflector assembly contains a plurality of vanes which change the direction of the solar energy to the vertical, while constantly keeping the same side of the deflector facing the sun. The vertical rays are then reflected off the stationary reflector and are then absorbed by the collector.

  10. Filmwise condensation of steam on low integral-finned tubes

    OpenAIRE

    Georgiadis, Ioannis V.

    1984-01-01

    Approved for public release; distribution is unlimited Filmwise condensation heat-transfer measurements if steam were made on horizontal tubes under vacuum and near-atmospheric pressures. Data were taken for a smooth tube and for 21 tubes which contained rectangularly-shaped, low integral fins. The fin geometry was systematically varied in order to investigate the dependence of the steam-side heat-transfer coefficient on fin spacing, thickness and height. The condensation process was fo...

  11. Investigation of enhancement of steam condensation heat transfer on finned tubes with porous drainage strips

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xijuan; Ma Tongze; Zhang Zhengfang

    1999-07-01

    Condensation of steam on horizontal finned tube with porous drainage strip was investigated experimentally and theoretically. Composite metal screens were used as porous drainage strip. Distilled water was taken in the experiments as working fluid. The experiments were carried out to find the structure effects of composite screen drainage strip on the condensation heat transfer on finned tubes with fin spacing of 0.5mm. Influences of the mesh number of both outer and inner layers and of length and thickness of the drainage strip were investigated. The outer layers of the screens have the mesh numbers of 100, 150, 185 and 220, which lead to different effective pore radius; the inner layers have the mesh numbers of 20, 30 and 40, which lead to different permeability. Strip lengths are 15mm, 20mm and 30mm, while the thickness is 2mm, 4mm and 6mm. Experimental results show that the structure parameters of the porous drainage strip strongly influence condensation on the finned tube. A porous strip having small effective pore radius on the outer layer as well as large permeability, reasonably large length and thickness will lead to excellent performance. In the tested ranges, for steam condensation on a 0.5mm spacing finned tube, the optimum structure of a composite screen drainage strip is of 150 mesh outer layer screen, 20 mesh inner layer screen, 30mm long and 4mm thick. The enhanced condensation heat transfer coefficients are equivalent to 1.15{approximately}1.74 times that of the finned tube and 2.08{approximately}3.08 times that of the plain tube. A new prediction model of condensation on finned tube with porous drainage strip was established. The condensate flow in the interfin grooves and in the porous strip was treated as flow through two kinds of porous medium with different structures. The momentum equation of single phase flow in porous medium was used to solve the condensate flow. The equation was analyzed and several terms were neglected because of their

  12. Horizontal drilling activity in Manitoba

    Energy Technology Data Exchange (ETDEWEB)

    Fox, J.

    1997-04-01

    An update of horizontal well drilling in Manitoba was provided. Manitoba`s productive formations are: (1) the Bakken Formation, (2) the Lodgepole Formation, (3) the Mission Canyon Formation, (4) the Amaranth Formation, and (5) the Melita Formation. A total of 28 exploratory wells and 29 development wells, including 11 horizontal wells were drilled in 1996. The 11 horizontal wells accounted for 30 per cent of the drilling meterage. The leading drillers for horizontal wells in Manitoba are Tundra Oil and Gas, Chevron, Anderson and HCO. Production from horizontal wells in 1996 totaled 310 cubic meter per day. To date, no horizontal wells have been drilled in the Bakken Formation. The least successful horizontal well application has been in the Lodgepole Formation. A summary of horizontal well production was provided for each Formation. 4 tabs., 10 figs.

  13. photomultiplier tube

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  14. photomultiplier tubes

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  15. A review on saturated boiling of liquids on tube bundles

    Science.gov (United States)

    Swain, Abhilas; Das, Mihir Kumar

    2014-05-01

    A review of recent investigation on boiling of saturated liquids over plain and enhanced tube bundles has been carried out taking the earlier review works as reference point. The experimental observations of various geometry and performance parameters studied by researchers are analyzed keeping current demand of industries in design and development of compact, efficient heat exchanging devices. The study shows that tube spacing plays an important role in determination of compactness of the heat exchanger.

  16. Improve seawater cooling with titanium finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    O' Donnell J. (High Performance Tube, Inc., Warren, NJ (United States))

    1992-10-01

    Seawater offers an endless supply of cooling water for these coastal processing facilities. But users must address seawater's corrosive nature in selecting construction materials for heat exchangers. Copper-nickel or carbon steel tubing fails continually under seawater service. This paper reports that titanium tubes, once thought to be too expensive a material for heat exchanger tubing, offer a unique combination of high material strength, excellent resistance to corrosion, and endurance to erosion by seawater. Titanium's superior physical properties in combination with enhanced surface area of low finned tubing perform the same heat duty with half the lineal footage of traditional heat exchanger tubes. High density low finned tubes multiply heat transfer capacity by a factor of two compared to plain tube. The technology applies in retrofit and original equipment manufacture (OEM) situations. It works best when the ratio of heat transfer coefficients is 2:1 or higher between the seawater coolant and shellside flow being cooled.

  17. Enhancenment of In-tube Condensation of Nonazeotropic Refrigerant Mixtures with a Micro-fin Tube

    Science.gov (United States)

    Koyama, Shigeru; Gao, Lei; Hujii, Tetsu

    Condensation heat transfer and pressure drop characteristics of nonazeotropic refrigerant mixtures (NARMs) of HCFC22 and CFC114 inside horizontal smooth and micro-fin tubes are experimentally investigated. The local Nusselt number for both tubes based on the temperature difference between bulk refrigerant and tube wall is compared. Data for the micro-fin tube are about 50% higher than those for the smooth tube in both cases of pure refrigerants and NARMs. In case of NARMs, however, the decrease of Nesselt number due to vapor mass transfer resistance is observed for the micro-fin tube as well as for the smooth tube. By assuming that heat transfer characteristics of the condensate of NARMs are similar to those for pure refrigerants, the vapor mass transfer coefficient of NARMs is evaluated. Comparison of frictional pressure drop for both tubes is also performed in the Lockharte-Martinelli relation. Data for the micro-fin tube are higer than those for the smooth tube. The maximum increase of the frictional pressure drop is about 30%.

  18. Specific yield, High Plains aquifer

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents specific-yield ranges in the High Plains aquifer of the United States. The High Plains aquifer underlies 112.6 million acres (176,000...

  19. Heat transfer characteristics of air cross-flow for in-line arrangement of spirally corrugated tube and smooth tube bundles

    Institute of Scientific and Technical Information of China (English)

    LU Guo-dong; ZHOU Qiang-tai; TIAN Mao-cheng; CHENG Lin; YU Xiao-li

    2005-01-01

    An experimental study on heat transfer and resistance coefficients of linearly arranged smooth and spirally corrugated tube bundles in cross-flow was performed. The heat transfer and resistance coefficients are presented in this paper with transverse and longitudinal tube-pitch and tube geometries taken into account. The experiment's results can provide technical guidelines for application to horizontal air preheater with arranged in-line spirally corrugated tube bundles, especially to the air preheater for CFBCBs (Circulating Fluidized Bed Combustion Boilers).

  20. A tube-in-tube thermophotovoltaic generator

    Energy Technology Data Exchange (ETDEWEB)

    Ashcroft, J.; Campbell, B.; Depoy, D.

    1996-12-31

    A thermophotovoltaic device includes at least one thermal radiator tube, a cooling tube concentrically disposed within each thermal radiator tube and an array of thermophotovoltaic cells disposed on the exterior surface of the cooling tube. A shell having a first end and a second end surrounds the thermal radiator tube. Inner and outer tubesheets, each having an aperture corresponding to each cooling tube, are located at each end of the shell. The thermal radiator tube extends within the shell between the inner tubesheets. The cooling tube extends within the shell through the corresponding apertures of the two inner tubesheets to the corresponding apertures of the two outer tubesheets. A plurality of the thermal radiator tubes can be arranged in a staggered or an in-line configuration within the shell.

  1. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL FINS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2005-01-01

    (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured......The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal fins. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...

  2. Wildlife associations in Rocky Mountain juniper in the northern Great Plains, South Dakota

    Science.gov (United States)

    Mark A. Rumble; John E. Gobeille

    1995-01-01

    Rocky Mountain juniper is an important habitat component in the northern Great Plains. These woodlands provide vertical and horizontal vegetative structure that enhances wildlife use. Ecological approaches to managing habitats require understanding relationships between wildlife species and succession in plant communities. We determined bird, small mammals and large...

  3. Well Spacing for Horizontal Wells

    Directory of Open Access Journals (Sweden)

    C.D.S. Keuengoua

    2011-06-01

    Full Text Available In the developing phase of a hydrocarbon reservoir and planning for drilling the production wells, it is necessary to drill the wells in an appropriate spacing to achieve maximum economic revenues during the reservoir life span. Well spacing which is the real location and interrelationship between producing oil or gas wells in an oil field is an important parameter. It is determined for the maximum ultimate production of a given reservoir and should be taken in consideration during well planning to avoid drilling of unnecessary wells. This study presents the concept of drainage area on horizontal well and horizontal productivity indices with different equations and their applications. A user friendly Excel Spreadsheet program was developed to calculate the productivity values of horizontal wells using three major available productivity equations. Also, the developed spreadsheet program was used to evaluate the effect of well spacing on the productivities of horizontal wells using productivity index approach and drainage area concept. It also helps to review the comparison between vertical and horizontal wells spacing based on drainage area concept. This program was validated, and then was used to study the effect of horizontal well length on the ratio of horizontal well productivity to vertical well productivity. The results show that higher ratio of horizontal well productivity to vertical well productivity values are obtained with increase length of the horizontal well. It is a very useful tool for making decision about the application of well spacing for horizontal wells.

  4. Feeding tube - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007235.htm Feeding tube - infants To use the sharing features on this page, please enable JavaScript. A feeding tube is a small, soft, plastic tube placed ...

  5. A Novel Endoscopic Technique for Failed Nasogastric Tube Placement.

    Science.gov (United States)

    Boston, Andrew G

    2015-10-01

    Direct visualization of the nasopharynx gives the otolaryngologist a unique advantage for addressing difficult nasopharyngeal anatomy. One common situation is being consulted to assist when the blind placement of a nasogastric tube has failed. A novel technique for managing a patient with a nasogastric tube embedded in the adenoid remnant is described with illustrations. The atraumatic method is easily employed by a resident armed with a portable nasolaryngoscope and plain suture. By using a repeated pull-through technique, the nasogastric tube can be guided past difficult nasopharyngeal anatomy and into a position from where it can be advanced into the patient's esophagus.

  6. Tube-shape verifier

    Science.gov (United States)

    Anderson, A. N.; Christ, C. R.

    1980-01-01

    Inexpensive apparatus checks accuracy of bent tubes. Assortment of slotted angles and clamps is bolted down to flat aluminum plate outlining shape of standard tube bent to desired configuration. Newly bent tubes are then checked against this outline. Because parts are bolted down, tubes can be checked very rapidly without disturbing outline. One verifier per tube-bending machine can really speed up production in tube-bending shop.

  7. PRODUCTIVITY OF FRACTURED HORIZONTAL WELLS

    Directory of Open Access Journals (Sweden)

    Stjepan Antolović

    2009-12-01

    Full Text Available The interest and performance of horizontal drilling and completions has increased during the last two decades. Horizontal wells are advantageous compared to vertical wells in thin reservoirs, reservoirs with favorable vertical permeability and reservoirs with water and gas coning problems. In many reservoirs, the ratio of horizontal permeability to the vertical permeability is substantially larger than one and often is close to 10. Thus, these reservoirs are very good candidates for hydraulic fracturing. By hydraulic fracturing one or more fractures are created, which can be longitudinal or orthogonal. By that, flow is altered and it mostly conducts horizontally through reservoir toward horizontal wellbore. With this altered flow, fluid is produced faster, with less pressure loss by fluid unit of produced fluid. Some of the existing mathematical models to determine the productivity of multifractured horizontal wells are presented in this work (the paper is published in Croatian.

  8. An experimental study on accelerated fouling of aluminum oxide and ferric oxide particles in internally enhanced tubes

    Energy Technology Data Exchange (ETDEWEB)

    Abedin, Mohammad Zoynal; Kim, Nae Hyun [School of Mechanical System Engineering, Incheon National University, Incheon (Korea, Republic of)

    2016-12-15

    This paper describes the results of accelerated particulate fouling tests performed on three enhanced tubes and a plain tube. The tests were performed using ferric oxide and aluminum oxide as foulant materials. Three enhanced tubes included 25 start, 10 start helically ribbed tubes and a ripple tube. Effects of the water velocity (0.9 to 1.8 m/s) and foulant concentration (750 to 2500 ppm) were investigated. At 750 ppm, the enhanced tubes fouled almost the same as the plain tube for the entire velocity range tested (0.9 to 1.8 m/s). The enhanced tube fouled faster than the plain tube for cases of high concentration combined with low velocities. Of the three enhanced tubes, the 25 start helically ribbed tube fouled faster than the ripple and the 10 start helically ribbed tubes. One thing to be noted is that the fouling concentrations used in the tests are significantly higher than would be expected in commercial heat exchangers. Also, the velocity range investigated is lower than would be expected in heat exchanger operation.

  9. Enhanced Heat Transfer Tubes for Absorber of Absorption Chiller/Heater

    Science.gov (United States)

    Furukawa, Masahiro; Sasaki, Naoe; Kaneko, Toshiyuki; Nosetani, Tadashi

    For the purpose of development of high performance absorption chiller/heater utilizing lithium bromide aqueous solution as working fluid, it is the most effective to improve the performance of absorber with the largest heat transfer area of the four heat exchangers. This paper introduces two kinds of double fluted tubes for the absorber of absorption chiller/heater. Arm tube and floral tube have about 40% higter heat transfer performance than the plain tube conventionally used in absorber. The former is manufactured by double drawbench process, while the latter by single drawbench process. Therefore, floral tube is expected to realize both high heat transfer perfoemance and low cost.

  10. Horizontal high-pressure air injection well construction and operation

    Energy Technology Data Exchange (ETDEWEB)

    Hume, J. [Continental Resources Inc., ND (United States)

    2005-07-01

    This paper discussed the design and operational challenges of a horizontal high-pressure air injection well currently in use at the Cedar Hill Red River B field in North Dakota. The field was developed in 1994, using horizontal wells oriented from the northeast to the southwest corners of each section on 640 acre spacing. In March of 2001, the field was unitized resulting in a horizontal waterflood project and a 320 acre horizontal high pressure air injection project. Extreme temperatures and pressures occurring in the reservoir from the combustion processes associated with high pressure air injection have resulted in several challenges. Reservoir and fluid properties of the field were presented, as well as a type log. Details of the Buffalo and Cedar Hills field were also provided, with a comparison of horizontal and vertical patterns. A light oil displacement process was reviewed, with details of tubing leak corrosion, packer seal and detonation failures. Burn front exposure to casing was discussed, and a wellbore diagram was provided. Various horizontal conversions were discussed. A description of the Cedar Hills Compressor Station and compression trains was provided. It was concluded that knowledge gained from 25 years of vertical high pressure air injection experience has been successfully incorporated to create a safe and durable design. 1 tab., 16 figs.

  11. Southeastern Coastal Plain aquifer system

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Southeastern Coastal Plain aquifer system in Kentucky, Tennessee, Mississippi, Alabama, Georgia, and South Carolina.

  12. DEMOGRAPHIC VULNERABILITIES IN TECUCI PLAIN

    Directory of Open Access Journals (Sweden)

    Iulian Adrian ŞORCARU

    2013-06-01

    Full Text Available The study focuses on analyzing and mapping 8 indicators considered to best reflect the demographic vulnerability in Tecuci Plain in the year 2010 and proposes a model of aggregation which finally allows us to distinguish three major types of demographic vulnerability (low, medium and high. Mapping the final values also shows significant disparities in the territorial administrative units that broadly overlap the plain, the most vulnerable being Tecuci city and the peripheral communes, towards Vrancea and Vaslui Counties.

  13. Heat Transfer Studies in Tube Banks with Integral Wake Splitters

    Directory of Open Access Journals (Sweden)

    Suzairin Md Seri

    2009-09-01

    Full Text Available This paper reports the findings from heat transfer studies with the presence of extended surfaces from tube banks which are termed as integral wake splitter plates. Employing this type of fins, investigations on heat transfer characteristics on a single circular tube as well as tube banks were carried out in cross flow of air in a rectangular duct. Experiments were carried out in the Reynolds number range 5 x 103 to 105 on a single cylinder of various splitter length-to-tube diameter ratios, L/D = 0.5, 1.0, 1.5 and 2.0. Further, tube banks consisting of 12 rows and 3 tubes per row in equilateral triangle arrangements with transverse pitch to diameter ratio, a = 2, were also investigated, the banks being made up of plain tubes or tubes with splitters. Heat transfer characteristics were studied for tubes with L/D = 0, 0.5 and 1.0 under constant heat flux conditions. Tube banks with L/D = 1.0 yielded the highest heat transfer rates. Findings from this work may be adopted to be utilized in various industrial applications such as economizer of a steam boiler, air-conditioning coils or waste heat recovery systems.

  14. Moving magnetic tubes: fragmentation, vortex streets and the limit of the approximation of thin flux tubes

    Science.gov (United States)

    Cheung, M. C. M.; Moreno-Insertis, F.; Schüssler, M.

    2006-05-01

    Aims.We study the buoyant rise of magnetic flux tubes in a stratified layer over a range of Reynolds numbers (25 ⪉ Re ⪉ 2600) by means of numerical simulations. Special emphasis is placed on studying the fragmentation of the rising tube, its trailing wake and the formation of a vortex street in the high-Reynolds number regime. Furthermore, we evaluate the relevance of the thin flux tube approximation with regard to describing the evolution of magnetic flux tubes in the simulations. Methods: .We used the FLASH code, which has an adaptive mesh refinement (AMR) algorithm, thus allowing the simulations to be carried out at high Reynolds numbers. Results: .The evolution of the magnetic flux tube and its wake depends on the Reynolds number. At Re up to a few hundred, the wake consists of two counter-rotating vortex rolls. At higher Re, the vortex rolls break up and the shedding of flux into the wake occurs in a more intermittent fashion. The amount of flux retained by the central portion of the tube increases with the field line twist (in agreement with previous literature) and with Re. The time evolution of the twist is compatible with a homologous expansion of the tube. The motion of the central portion of the tube in the simulations is very well described by the thin flux tube model whenever the effects of flux loss or vortex forces can be neglected. If the flux tube has an initial net vorticity, it undergoes asymmetric vortex shedding. In this case, the lift force accelerates the tube in such a way that an oscillatory horizontal motion is super-imposed on the vertical rise of the tube, which leaves behind a vortex street. This last result is in accordance with previous simulations reported in the literature, which were carried out at lower Reynolds number.

  15. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL FINS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2005-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal fins. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...... (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured......, temperature of inlet flow and collector tilt angle are shown. Based on the investigations preliminary recommendations for the operation of the investigated collector are given. For instance, minimum flow rate in order to avoid boiling in the horizontal strips is recommended....

  16. The Simulation and Test for Piezoelectric Composite Tube

    Directory of Open Access Journals (Sweden)

    Wang Hongwei

    2016-01-01

    Full Text Available Piezoelectric composite circular tube has been developed,this tube is used for underwater acoustic transducer. The finite element simulation has been done for piezoelectric composite material tube, and gained the tube structure parameters. In accordance with the structural parameters obtained from the simulation, the composite circular tube is processed and its performance has been tested. the results show as follow: Acoustic impedance is 18.05 (Pa·s/m3, relative permittivity is 859, sound velocity is 3200m/s, d33 constant is 480 pC/N, vibration displacement is 89.5pm, the resonant frequency is 388kHz, bandwidth is 11.2kHz,. The piezoelectric composite circular tubes suitable for horizontal omnidirectional broadband transducer.

  17. Usefulness of plain radiography for assessing hypouricemic treatment response in patients with tophaceous gout.

    Science.gov (United States)

    Suh, Young Sun; Cheon, Yun-Hong; Kim, Ji Eun; Kim, Ji-Min; Kim, Sang-Hyon; Lee, Won-Seok; Yoo, Wan-Hee; Lee, Sang-Il; Kim, Hyun-Ok

    2016-11-01

    To investigate whether plain radiography is useful for assessing the changes in gouty tophi size following hypouricemic therapy. Gout was diagnosed according to the American College of Rheumatology criteria. Before and after hypouricemic treatment, serum uric acid level was measured, and plain radiography was performed to measure gouty tophi size. The tophi were graded by measuring the maximum vertical and horizontal diameters, and they were scored by adding up the scores of the grades. The vertical diameter was measured on both sides of the proximal phalanges (PPs). The horizontal diameter was measured on the lateral side of the PPs. The maximum vertical diameter measurement was graded 0-4. The maximum horizontal diameter measurement was graded 0-3. Seven hundred first metatarsal phalangeal joints (MTPJ) of 350 patients with gout were assessed for gouty tophi. Tophi were observed using plain radiography in 174 MTPJs (24.9%) of 109 patients (31.1%). Follow-up plain radiography was performed in 60 of these patients. Before the treatment, the average serum uric acid level of these patients was 8.3 ± 1.9 mg/dL, and the average tophi score was 3.7 ± 2.5. After hypouricemic treatment, the uric acid level decreased to 5.9 ± 1.6 mg/dL (P treatment. © 2016 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.

  18. Heat Transfer Enhancement of Shell and Tube Heat Exchanger Using Conical Tapes.

    Directory of Open Access Journals (Sweden)

    Dhanraj S.Pimple

    2014-12-01

    Full Text Available This paper provides heat transfer and friction factor data for single -phase flow in a shell and tube heat exchanger fitted with a helical tape insert. In the double concentric tube heat exchanger, hot air was passed through the inner tube while the cold water was flowed through the annulus. The influences of the helical insert on heat transfer rate and friction factor were studied for counter flow, and Nusselt numbers and friction factor obtained were compared with previous data (Dittus 1930, Petukhov 1970, Moody 1944 for axial flows in the plain tube. The flow considered is in a low Reynolds number range between 2300 and 8800. A maximum percentage gain of 165% in heat transfer rate is obtained for using the helical insert in comparison with the plain tube.

  19. Mechanical and mathematical models of multi-stage horizontal fracturing strings and their application

    OpenAIRE

    Zhanghua Lian; Ying Zhang; Xu Zhao; Shidong Ding; Tiejun Lin

    2015-01-01

    Multi-stage SRV fracturing in horizontal wells is a new technology developed at home and abroad in recent years to effectively develop shale gas or low-permeability reservoirs, but on the other hand makes the mechanical environment of fracturing strings more complicated at the same time. In view of this, based on the loading features of tubing strings during the multi-stage fracturing of a horizontal well, mechanical models were established for three working cases of multiple packer setting, ...

  20. Identification of thick sedimentary plains north of Hellas

    Science.gov (United States)

    Salese, Francesco; Mangold, Nicolas; Ansan, Veronique; Carter, John; Ody, Anouck; Poulet, François; Ori, Gian Gabriele

    2016-04-01

    Understanding the origin and timing of intercrater plains is crucial to understand the Martian history in relation with endogenic and/or exogenic cycles. Intercrater plains north of Hellas basin on Mars are thought to have hosted different sedimentary environments during the Late Noachian/Early Hesperian, and they offer a well-preserved insight into the regional geological history of Mars. Our new geologic mapping of the intercrater plains north of Hellas Basin is based on the rich data set from MRO and Mars Express and provides new insights into the region's geological history. These findings appear to constrain the interpretation of the nature and age of intercrater plains in this region, although we acknowledge that for example the source of the sedimentary deposits must be subject to further analysis. The northern part of Hellas basin displays topographically flat area, which was characterized during the Late Noachian by sedimentary deposition and later, in the Late Hesperian, by fissural volcanism. The map and crater retention ages enable us to interpret the geologic history of the region. The stratigraphically lower unit is represented by crustal outcrops. Across most of the region, the sedimentary unit covers the basement and is eroded into mesas, erosional windows and perched by fresh craters. Intercrater plains' sedimentary deposits north of Hellas display horizontal light-toned layered rich in Fe/Mg-phyllosilicates and local crossbedding stratification. The Noachian sedimentary deposits of the intercrater plains north of Hellas are locally covered by Hesperian lava flows, showing that intercrater plains are sedimentary and volcanic in origin. We found different erosional (regional and local) surfaces, at HiRISE scale inside sediments due to local erosional windows and at CTX scale we found two important regional erosional surfaces. The oldest between crustal outcrops and sediments, which is likely Middle Noachian in age and the youngest between sediments

  1. Horizontal and Vertical Line Designs.

    Science.gov (United States)

    Johns, Pat

    2003-01-01

    Presents an art lesson in which students learn about the artist Piet Mondrian and create their own abstract artworks. Focuses on geometric shapes using horizontal and vertical lines. Includes background information about the artist. (CMK)

  2. Experimental investigation of horizontal convection

    OpenAIRE

    Muñoz Córdoba, Lucía

    2015-01-01

    Fluid circulation driven by buoyancy forces due to a thermal gradient on a horizontal boundary, known as horizontal convection, is experimentally studied. For that purpose, a methacrylate box with inner dimensions 300x150x150 mm3 (LxWxH) whose bottom is composed by a heat exchanger and a printed circuit board is lled with water. The heat exchanger provides a uniform temperature boundary condition while the printed circuit board provides a boundary condition of uniform heat ...

  3. Analysis of thermal stresses in horizontal delivery water heaters

    Science.gov (United States)

    Bilan, A. V.; Plotnikov, P. N.

    2016-11-01

    Analysis of thermal stresses in tubes and a compensator, taking into account water heating in each heater bunch and temperature at which its mounting is implemented, and of stresses on pressure is presented. The 3D-model of the horizontal delivery water heater of PSG-4900-0.3-1.14 type is used. The tube plate is represented as the 3D-body with 6863 holes with offset center of the perforated area, the steam space shell is represented as a cylindrical casing, the bottoms of water chambers are considered as elliptical casings, the four-lens compensator is represented in the form of toroidal casings, and the tubes are considered as beams operating in tensile-compression and bending in two planes. Calculations were carried out for different temperatures of superheated steam and a steam space shell, respectively, as well as designs with compensator and without it. Various temperature values of the tubes on the passes were calculated and set. The studies were carried out taking into account nonaxis-symmetrical spacing the tube plate and compensator deformation. The calculation results of tensile-compression stresses in the tubes are presented. Furthermore, the central tubes experience compressive stresses, whose maximal values take place on the border between the tubes of the fourth and of the first passes. For its decrease, it is recommended to increase the distance between the tubes of these passes. The tension stresses in the peripheral tubes are the maximal stresses. To reduce the stresses and, therefore, increase service life of the delivery water heater at using wet or superheated (not more than by 30-50°C) steam in it (the larger value refers to the brass tubes and the water pressure of 1.6-2.5 MPa), it is necessary to recommend the noncompensatory design at using the steam superheated by more than 30-50°C (at Ural Turbine Works, it is the turbines of T-250/300-23.5 and T-113/145-12.4 types with intermediate superheating) and to recommend the installation of the

  4. Saturated thickness, High Plains aquifer, 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents the saturated thickness of the High Plains aquifer of the United States, 2009, in feet. The High Plains aquifer underlies...

  5. Feeding tube insertion - gastrostomy

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002937.htm Feeding tube insertion - gastrostomy To use the sharing features on this page, please enable JavaScript. A gastrostomy feeding tube insertion is the placement of a feeding ...

  6. Neural Tube Defects

    Science.gov (United States)

    Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In ...

  7. Horizontal fiscal imbalance in Germany

    Directory of Open Access Journals (Sweden)

    Paweł Kowalik

    2015-04-01

    Full Text Available Regional inequalities are currently a challenge for the majority of the countries, in particular the large ones. The problem of public income redistribution emerges due to possible differentiation of the economic development level of territorial units. The most often considered problem is the vertical distribution. The horizontal division of income is far less frequently considered. Horizontal fiscal imbalance or regional tax inequalities seem to be graver than the vertical imbalance, particularly in developing countries. The public finance system, in particular in federations, is often very complex. Public finance of federations and federated states are not often based on the same assumptions. This leads to differences among regions, both vertical and horizontal. The use of the presented measures helps identify those differences and permits developing mechanisms equalising those inequalities. It should be remembered that those measures may have certain drawbacks, and they mainly focus on certain specific values of income redistribution. Thereby several measures should be applied in measurements and the obtained results should be compared. There are no up-to-date measurements and comparisons of horizontal fiscal imbalance among countries.. The aim of this paper is to measure horizontal fiscal imbalance in Germany, especially after reunification, which represents one of two models of federalism. At the beginning it shows the static and dynamic measurements presented in the literature that can be used to measure the horizontal fiscal imbalance. And then it is followed by the results of calculations for Germany in the period 1970-2013. As expected, horizontal imbalance was much lower before than after the reunification of Germany. After the reunification there were large disparities between "old" and "new" länder. This imbalance is gradually reduced. In comparison with the results obtained for the USA [Kowalik 2014, pp. 144-148] it can be said

  8. An Inexpensive and Versatile Version of Kundt's Tube for Measuring the Speed of Sound in Air

    Science.gov (United States)

    Papacosta, Pangratios; Linscheid, Nathan

    2016-01-01

    Experiments that measure the speed of sound in air are common in high schools and colleges. In the Kundt's tube experiment, a horizontal air column is adjusted until a resonance mode is achieved for a specific frequency of sound. When this happens, the cork dust in the tube is disturbed at the displacement antinode regions. The location of the…

  9. Experimental Study on Heat Transfer Characteristics of Shell and Tube Heat Exchanger Using Hitran Wire Matrix Turbulators As Tube Inserts.

    Directory of Open Access Journals (Sweden)

    Manoj

    2014-06-01

    Full Text Available Shell and tube heat exchangers are extensively used in boilers, oil coolers, pre-heaters, condensers etc. They are also having special importance in process application as well as refrigeration and air conditioning industries. The present paper emphasizes on heat transfer characteristics of shell and tube heat exchangers with the aid of hiTRAN wire matrix inserts is been studied. Investigations were made on effect of mass flow rate of water on heat transfer characteristics in case of plain tube without inserts. When hiTRAN wire matrix tube inserts are used, which effectively increases the turbulence of tube side flow due to the hydrodynamic and thermal agitation of boundary layer in turns increases additional pressure drop is available in the system. This results in increase in the wall shear, reduced wall temperature which enhances substantial increase in tube side heat transfer characteristics. Heat and cooling processes streams is a standard operation in many industries this operation is often performed in heat exchangers where the heated or cold fluid flows under laminar conditions inside the tubes the mechanisms of under those flow conditions are complex poorly understood since they can involve both forced and natural convection making accurate prediction for heat exchanger. Heat transfer in laminar flow regimes is low by default but can be greatly increased by the use of passive heat transfer enhancement such as tube inserts. The present analysis the hiTRAN wire matrix turbulators were used and increased heat transfer characteristics as expected outcomes.

  10. Vortex tubes in the wave bottom boundary layer

    NARCIS (Netherlands)

    Henriquez, M.; Reniers, A.J.H.M.; Ruessink, B.G.; Stive, M.J.F.

    2012-01-01

    The cause of sediment suspension events during flow reversal under waves in the nearshore is not well understood. Vortex tubes and horizontal pressure gradients have been suggested to be the cause of the suspension events. A medium sized wave flume experiment has been conducted to give insight in th

  11. DRILL BITS FOR HORIZONTAL WELLS

    Directory of Open Access Journals (Sweden)

    Paolo Macini

    1996-12-01

    Full Text Available This paper underlines the importance of the correct drill bit application in horizontal wells. Afler the analysis of the peculiarities of horizontal wells and drainholes drilling techniques, advantages and disadvantages of the application of both roller cone and fixed cutters drill bits have been discussed. Also, a review of the potential specific featuries useful for a correct drill bit selection in horizontal small diameter holes has been highlighted. Drill bits for these special applications, whose importance is quickly increasing nowadays, should be characterised by a design capable to deliver a good penetration rate low WOB, and, at the same time, be able to withstand high RPM without premature cutting structure failure and undergauge. Formation properties will also determine the cutting structure type and the eventual specific features for additional gauge and shoulder protection.

  12. Intercostal drainage tube or intracardiac drainage tube?

    Directory of Open Access Journals (Sweden)

    N Anitha

    2016-01-01

    Full Text Available Although insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure.

  13. Plain Polynomial Arithmetic on GPU

    Science.gov (United States)

    Anisul Haque, Sardar; Moreno Maza, Marc

    2012-10-01

    As for serial code on CPUs, parallel code on GPUs for dense polynomial arithmetic relies on a combination of asymptotically fast and plain algorithms. Those are employed for data of large and small size, respectively. Parallelizing both types of algorithms is required in order to achieve peak performances. In this paper, we show that the plain dense polynomial multiplication can be efficiently parallelized on GPUs. Remarkably, it outperforms (highly optimized) FFT-based multiplication up to degree 212 while on CPU the same threshold is usually at 26. We also report on a GPU implementation of the Euclidean Algorithm which is both work-efficient and runs in linear time for input polynomials up to degree 218 thus showing the performance of the GCD algorithm based on systolic arrays.

  14. Modelling of Heat Transfer Phenomena for Vertical and Horizontal Configurations of In-Pool Condensers and Comparison with Experimental Findings

    Directory of Open Access Journals (Sweden)

    Davide Papini

    2010-01-01

    Different condenser tube arrangements have been developed for applications to the next generation NPPs. The two most used configurations, namely, horizontal and vertical tube condensers, are thoroughly investigated in this paper. Several thermal-hydraulic features were explored, being the analysis mainly devoted to the description of the best-estimate correlations and models for heat transfer coefficient prediction. In spite of a more critical behaviour concerning thermal expansion issues, vertical tube condensers offer remarkably better thermal-hydraulic performances. An experimental validation of the vertical tube correlations is provided by PERSEO facility (SIET labs, Piacenza, showing a fairly good agreement.

  15. Southern Great Plains Safety Orientation

    Energy Technology Data Exchange (ETDEWEB)

    Schatz, John

    2014-05-01

    Welcome to the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ARM) Southern Great Plains (SGP) site. This U.S. Department of Energy (DOE) site is managed by Argonne National Laboratory (ANL). It is very important that all visitors comply with all DOE and ANL safety requirements, as well as those of the Occupational Safety and Health Administration (OSHA), the National Fire Protection Association, and the U.S. Environmental Protection Agency, and with other requirements as applicable.

  16. Pulse Tube Refrigerator

    Science.gov (United States)

    Matsubara, Yoichi

    The pulse tube refrigerator is one of the regenerative cycle refrigerators such as Stirling cycle or Gifford-McMahon cycle which gives the cooling temperature below 150 K down to liquid helium temperature. In 1963, W. E. Gifford invented a simple refrigeration cycle which is composed of compressor, regenerator and simple tube named as pulse tube which gives a similar function of the expander in Stirling or Gifford-McMahon cycle. The thermodynamically performance of this pulse tube refrigerator is inferior to that of other regenerative cycles. In 1984, however, Mikulin and coworkers made a significant advance in pulse tube configuration called as orifice pulse tube. After this, several modifications of the pulse tube hot end configuration have been developed. With those modifications, the thermodynamic performance of the pulse tube refrigerator became the same order to that of Stirling and Gifford-McMahon refrigerator. This article reviews the brief history of the pulse tube refrigerator development in the view point of its thermodynamically efficiency. Simplified theories of the energy flow in the pulse tube have also been described.

  17. Horizontal Diplopia Following Upper Blepharoplasty

    Directory of Open Access Journals (Sweden)

    Tomás Ortiz-Basso

    2014-09-01

    Full Text Available Diplopia is an infrequent complication after blepharoplasty. Most of the cases are in its vertical form due to trauma of the extraocular muscles. In this article, we present a case of horizontal diplopia following cosmetic upper blepharoplasty; we review the literature on this unexpected complication and offer some recommendations to avoid it.

  18. CFD Analysis of Plate Fin Tube Heat Exchanger for Various Fin Inclinations

    OpenAIRE

    2014-01-01

    ANSYS Fluent software is used for three dimensional CFD simulations to investigate heat transfer and fluid flow characteristics of six different fin angles with plain fin tube heat exchangers. The numerical simulation of the fin tube heat exchanger was performed by using a three dimensional numerical computation technique. Geometry of model is created and meshed by using ANSYS Workbench software. To solve the equation for the fluid flow and heat transfer analysis ANSYS FLUENT ...

  19. Enhanced tubes for steam condensers. Volume 1, Summary of condensation and fouling; Volume 2, Detailed study of steam condensation

    Energy Technology Data Exchange (ETDEWEB)

    Webb, R.L.; Chamra, L.; Jaber, H.

    1992-02-01

    Electric utility steam condensers typically use plain tubes made of titanium, stainless steel, or copper alloys. Approximately two-thirds of the total thermal resistance is on the water side of the plain tube. This program seeks to conceive and develop a tube geometry that has special enhancement geometries on the tube (water) side and the steam (shell) side. This ``enhanced`` tube geometry, will provide increased heat transfer coefficients. The enhanced tubes will allow the steam to condense at a lower temperature. The reduced condensing temperature will reduce the turbine heat rate, and increase the plant peak load capability. Water side fouling and fouling control is a very important consideration affecting the choice of the tube side enhancement. Hence, we have consciously considered fouling potential in our selection of the tube side surface geometry. Using appropriate correlations and theoretical models, we have designed condensation and water side surface geometries that will provide high performance and be cleanable using sponge ball cleaning. Commercial tube manufacturers have made the required tube geometries for test purposes. The heat transfer test program includes measurement of the condensation and water side heat transfer coefficients. Fouling tests are being run to measure the waterside fouling resistance, and to the test the ability of the sponge ball cleaning system to clean the tubes.

  20. Heated Tube Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Heated Tube Facility at NASA GRC investigates cooling issues by simulating conditions characteristic of rocket engine thrust chambers and high speed airbreathing...

  1. Fuel nozzle tube retention

    Energy Technology Data Exchange (ETDEWEB)

    Cihlar, David William; Melton, Patrick Benedict

    2017-02-28

    A system for retaining a fuel nozzle premix tube includes a retention plate and a premix tube which extends downstream from an outlet of a premix passage defined along an aft side of a fuel plenum body. The premix tube includes an inlet end and a spring support feature which is disposed proximate to the inlet end. The premix tube extends through the retention plate. The spring retention feature is disposed between an aft side of the fuel plenum and the retention plate. The system further includes a spring which extends between the spring retention feature and the retention plate.

  2. Steam generator tube failures

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service.

  3. Horizontally oriented plates in clouds

    CERN Document Server

    Bréon, François-Marie

    2011-01-01

    Horizontally oriented plates in clouds generate a sharp specular reflectance signal in the glint direction, often referred to as "subsun". This signal (amplitude and width) may be used to analyze the relative area fraction of oriented plates in the cloud top layer and their characteristic tilt angle to the horizontal. We make use of spaceborne measurements from the POLDER instrument to provide a statistical analysis of these parameters. More than half of the clouds show a detectable maximum reflectance in the glint direction, although this maximum may be rather faint. The typical effective fraction (area weighted) of oriented plates in clouds lies between 10-3 and 10-2. For those oriented plates, the characteristic tilt angle is less than 1 degree in most cases. These low fractions imply that the impact of oriented plates on the cloud albedo is insignificant. The largest proportion of clouds with horizontally oriented plates is found in the range 500-700 hPa, in agreement with typical in situ observation of p...

  4. Partial Horizontal Laryngectomy and Epiglottiplasty

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In order to evaluate the availability of the lateral horizontal laryngectomy and anaplasty of epiglottis to treat somepatients with specific supraglottic carcinomas and hypopharyngeal carcinomas, 17 cases of laryngeal and hypopharyngeal carcinomas were retrospectively analyzed, whose tumors were located at the lateral margin of epiglottis, aryepiglottic fold, medial wall of piriformfossa and were treated by the lateral horizontal laryngectomy and anaplasty of epiglottis. The results showed that all cases took food by mouth in postoperative 9-14 days and subjected to decannulation in postoperative 9-15 days. Three cases had postoperative hoarse voice. The free-disease survival rate of 3 years was 71.4 % in 14 cases followed up after the first surgical therapy, and the overall free-disease survival rate of 3 years was 85.7 % after the second surgical therapy. It was concluded that the manipulations of the lateral horizontal laryngectomy and epiglottiplasty were simple. It could alleviate the postoperative symptoms of aspiration and bucking remarkably and shorten their postoperative recovery time, yet does not lower the survival rate of patients if laryngocarcinoma or hypopharyngeal carcinoma cases were properly selected.

  5. Development of Empirical Correlation to Calculate Pool Boiling Heat Transfer of Tandem Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Myeong-Gie [Andong National University, Andong (Korea, Republic of)

    2015-10-15

    The heat exchanging tubes are in vertical alignment. For the cases, the upper tube is affected by the lower tube. Since heat transfer is closely related to the conditions of tube surface, bundle geometry, and liquid, lots of studies have been carried out for the several decades to investigate the combined effects of those factors on pool boiling heat transfer. One of the most important parameters in the analysis of a tube array is the pitch ( P ) between tubes. Many researchers have been investigated its effect on heat transfer enhancement for the tube bundles and the tandem tubes. The effect of a tube array on heat transfer enhancement was also studied for application to the flooded evaporators. Cornwell and Schuller studied the sliding bubbles by high speed photography to account the enhancement of heat transfer observed at the upper tubes of a bundle. The study by Memory et al. shows the effects of the enhanced surface and oil adds to the heat transfer of tube bundles. They identified that, for the structured and porous bundles, oil addition leads to a steady decrease in performance. The flow boiling of n-pentane across a horizontal tube bundle was investigated experimentally by Roser et al. They identified that convective evaporation played a significant part of the total heat transfer. The fouling of the tube bundle under pool boiling was also studied by Malayeri et al. They identified that the mechanisms of fouling on the middle and top heater substantially differ from those at the bottom heater.

  6. Hologram recording tubes

    Science.gov (United States)

    Rajchman, J. H.

    1973-01-01

    Optical memories allow extremely large numbers of bits to be stored and recalled in a matter of microseconds. Two recording tubes, similar to conventional image-converting tubes, but having a soft-glass surface on which hologram is recorded, do not degrade under repeated hologram read/write cycles.

  7. Plateaus and sinuous ridges as the fingerprints of lava flow inflation in the Eastern Tharsis Plains of Mars

    Science.gov (United States)

    Bleacher, Jacob E.; Orr, Tim; de Wet, Andrew P.; Zimbelman, James R.; Hamilton, Christopher W.; Garry, W. Brent; Crumpler, Larry S.; Williams, David A.

    2017-01-01

    The Tharsis Montes rift aprons are composed of outpourings of lava from chaotic terrains to the northeast and southwest flank of each volcano. Sinuous and branching channel networks that are present on the rift aprons suggest the possibility of fluvial processes in their development, or erosion by rapidly emplaced lavas, but the style of lava flow emplacement throughout rift apron development is not clearly understood. To better characterize the style of lava emplacement and role of fluvial processes in rift apron development, we conducted morphological mapping of the Pavonis Mons southwest rift apron and the eastern Tharsis plains using images from the High Resolution Imaging Science Experiment (HiRISE), Mars Orbiter Camera (MOC), Context Camera (CTX), Thermal Emission Imaging System (THEMIS), and High Resolution Stereo Camera (HRSC) along with the Mars Orbiter Laser Altimeter (MOLA) Precision Experiment Data Records (PEDRs) and gridded data. Our approach was to: (1) search for depositional fans at the slope break between the rift apron and adjacent low slope plains; (2) determine if there is evidence that previously formed deposits might have been buried by plains units; (3) characterize the Tharsis plains morphologies east of Pavonis Mons; and (4) assess their relationship to the rift apron units. We have not identified topographically significant depositional fans, nor did we observe evidence to suggest that plains units have buried older rift apron units. Flow features associated with the rift apron are observed to continue across the slope break onto the plains. In this area, the plains are composed of a variety of small fissures and low shield vents around which broad channel-fed and tube-fed flows have been identified. We also find broad, flat-topped plateaus and sinuous ridges mixed among the channels, tubes and vents. Flat-topped plateaus and sinuous ridges are morphologies that are analogous to those observed on the coastal plain of Hawai‘i, where lava

  8. Molybdenum Tube Characterization report

    Energy Technology Data Exchange (ETDEWEB)

    Beaux II, Miles Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Usov, Igor Olegovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-07

    Chemical vapor deposition (CVD) techniques have been utilized to produce free-standing molybdenum tubes with the end goal of nuclear fuel clad applications. In order to produce tubes with properties desirable for this application, deposition rates were lowered requiring long deposition durations on the order of 50 hours. Standard CVD methods as well as fluidized-bed CVD (FBCVD) methods were applied towards these objectives. Characterization of the tubes produced in this manner revealed material suitable for fuel clad applications, but lacking necessary uniformity across the length of the tubes. The production of freestanding Mo tubes that possess the desired properties across their entire length represents an engineering challenge that can be overcome in a next iteration of the deposition system.

  9. Categorising YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s...... technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition...... and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within...

  10. Wavy tube heat pumping

    Energy Technology Data Exchange (ETDEWEB)

    Haldeman, C. W.

    1985-12-03

    A PVC conduit about 4'' in diameter and a little more than 40 feet long is adapted for being seated in a hole in the earth and surrounds a coaxial copper tube along its length that carries Freon between a heat pump and a distributor at the bottom. A number of wavy conducting tubes located between the central conducting tube and the wall of the conduit interconnect the distributor with a Freon distributor at the top arranged for connection to the heat pump. The wavy conducting tubing is made by passing straight soft copper tubing between a pair of like opposed meshing gears each having four convex points in space quadrature separated by four convex recesses with the radius of curvature of each point slightly less than that of each concave recess.

  11. Heat transfer enhancement through inner grooved copper tubes with different tube parameters

    Directory of Open Access Journals (Sweden)

    M. M. Rahman, Y. M. Ling, G. W. Soon, G. A. Kuan

    2012-01-01

    Full Text Available This paper presents the evaluation of heat transfer coefficients for the flow of R22 through internally grooved copper tubes. A series of tests were conducted using two types of tubes namely Tube A and Tube B, which have different tube parameters. The straight and horizontal test section of the test apparatus with a length of 3.67 m was heated or cooled by water circulated in a surrounding annulus. Condensation tests were conducted at mass flux rates of 180 to 537 kg/m2s and the vapor qualities ranged from a nominal value of 83% at the test section inlet to 6% at the outlet. Evaporation tests were conducted at mass flux rates of 110 to 404 kg/m2s and the nominal vapor qualities at the inlet and outlet were 0 and 85%, respectively. For both the condensation and evaporation tests, the heat transfer coefficients are found to increase as the mass flux rate increases.

  12. The root caused analysis of leakaged heat exchanger tube; Ursachenanalyse einer Leckage an einem Waermeuebertraegerrohr

    Energy Technology Data Exchange (ETDEWEB)

    Shamsudin, Shaiful Rizam; Salleh, M.A.A. Mohd; Rahmat, Azmi; Anuar, Mohd Arif [Universiti Malaysia Perlis (UniMAP) (Malaysia). Center of Excellence Geopolymer and Green Technology (CEGeoGTech); Harun, Mohd; Zayid, Hafizal [Malaysian Nuclear Agency, Selangor (Malaysia). Industry Technology Div.; Noor, Mazlee Mohd [Universiti Malaysia Perlis (UniMAP) (Malaysia). School of Materials Engineering

    2015-05-01

    AISI type 316L stainless steel was used as a heat exchanger tube material in an inter-cooler column. After less than a year of operation, severe corrosion failures occurred and a transverse opening leakage was observed on one of the heat exchanger tubes. The failed tube was carefully analyzed using various metallurgical laboratory equipments. The root cause of the tube leakage was believed due to the presence of horizontal micro and macro pores as a hydrogen gas entrapment during casting of the parent ingot. The overlapped and gaping pores formed notch on the shell side of the tube surface, and it increasingly evident when the use of a high-energy water-jet and metal brush as cleaning procedure results in an establishment of pitting type local-action corrosion cells penetrated the tube wall. As a result, corrosive fluid in the tube side dissolved into the cooling water, accelerating the corrosion process.

  13. What Are Neural Tube Defects?

    Science.gov (United States)

    ... NICHD Research Information Clinical Trials Resources and Publications Neural Tube Defects (NTDs): Condition Information Skip sharing on social media links Share this: Page Content What are neural tube defects? Neural (pronounced NOOR-uhl ) tube defects are ...

  14. Acute diaphragmatic paralysis caused by chest-tube trauma to phrenic nerve

    Energy Technology Data Exchange (ETDEWEB)

    Nahum, E.; Ben-Ari, J.; Schonfeld, T. [Pediatric Intensive Care Unit, Schneider Children' s Medical Center of Israel, Petah Tiqva (Israel); Horev, G. [Dept. of Diagnostic Radiology, Schneider Children' s Medical Center of Israel, Petah Tiqva (Israel); Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel)

    2001-06-01

    A 3{sup 1}/{sub 2}-year-old child developed unilateral diaphragmatic paralysis after chest drain insertion. Plain chest X-ray demonstrated paravertebral positioning of the chest-tube tip, and magnetic resonance imaging revealed hematomas in the region of the chest-tube tip and the phrenic nerve fibers. The trauma to the phrenic nerve was apparently secondary to malposition of the chest tube. This is a rare complication and has been reported mainly in neonates. Radiologists should notify the treating physicians that the correct position of a chest drain tip is at least 2 cm distant from the vertebrae. (orig.)

  15. Exit and Paradise Creek Braid Plain Kilometers, 2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset consists of points designating braid plain kilometers, or distance along the braid plain centerline, for the 2012 active braid plain of Exit Creek and...

  16. Panspermia and horizontal gene transfer

    Science.gov (United States)

    Klyce, Brig

    2009-08-01

    Evidence that extremophiles are hardy and ubiquitous is helping to make panspermia a respectable theory. But even if life on Earth originally came from space, biologists assume that the subsequent evolution of life is still governed by the darwinian paradigm. In this review we show how panspermia could amend darwinism and point to a cosmic source for, not only extremophiles but, all of life. This version of panspermia can be called "strong panspermia." To support this theory we will discuss recent evidence pertaining to horizontal gene transfer, viruses, genes apparently older than the Earthly evolution of the features they encode, and primate-specific genes without identifiable precursors.

  17. Two-Phase Flow Field Simulation of Horizontal Steam Generators

    Directory of Open Access Journals (Sweden)

    Ataollah Rabiee

    2017-02-01

    Full Text Available The analysis of steam generators as an interface between primary and secondary circuits in light water nuclear power plants is crucial in terms of safety and design issues. VVER-1000 nuclear power plants use horizontal steam generators which demand a detailed thermal hydraulics investigation in order to predict their behavior during normal and transient operational conditions. Two phase flow field simulation on adjacent tube bundles is important in obtaining logical numerical results. However, the complexity of the tube bundles, due to geometry and arrangement, makes it complicated. Employment of porous media is suggested to simplify numerical modeling. This study presents the use of porous media to simulate the tube bundles within a general-purpose computational fluid dynamics code. Solved governing equations are generalized phase continuity, momentum, and energy equations. Boundary conditions, as one of the main challenges in this numerical analysis, are optimized. The model has been verified and tuned by simple two-dimensional geometry. It is shown that the obtained vapor volume fraction near the cold and hot collectors predict the experimental results more accurately than in previous studies.

  18. Isolated Fallopian Tube Torsion

    Directory of Open Access Journals (Sweden)

    S. Kardakis

    2013-01-01

    Full Text Available Isolated torsion of the Fallopian tube is a rare gynecological cause of acute lower abdominal pain, and diagnosis is difficult. There are no pathognomonic symptoms; clinical, imaging, or laboratory findings. A preoperative ultrasound showing tubular adnexal masses of heterogeneous echogenicity with cystic component is often present. Diagnosis can rarely be made before operation, and laparoscopy is necessary to establish the diagnosis. Unfortunately, surgery often is performed too late for tube conservation. Isolated Fallopian tube torsion should be suspected in case of acute pelvic pain, and prompt intervention is necessary.

  19. Optimization of friction welding by taguchi and ANOVA method on commercial aluminium tube to Al 2025 tube plate with backing block using an external tool

    Energy Technology Data Exchange (ETDEWEB)

    Kanna, S.; Kumaraswamidhs, L. A. [Indian Institute of Technology, Dhanbad (India); Kumaran, S. Senthil [RVS School of Engineering and Technology, Dindigul (India)

    2016-05-15

    The aim of the present work is to optimize the Friction welding of tube to tube plate using an external tool (FWTPET) with clearance fit of commercial aluminum tube to Al 2025 tube plate using an external tool. Conventional frictional welding is suitable to weld only symmetrical joints either tube to tube or rod to rod but in this research with the help of external tool, the welding has been done by unsymmetrical shape of tube to tube plate also. In this investigation, the various welding parameters such as tool rotating speed (rpm), projection of tube (mm) and depth of cut (mm) are determined according to the Taguchi L9 orthogonal array. The two conditions were considered in this process to examine this experiment; where condition 1 is flat plate with plain tube Without holes [WOH] on the circumference of the surface and condition 2 is flat plate with plane tube has holes on its circumference of the surface With holes [WH]. Taguchi L9 orthogonal array was utilized to find the most significant control factors which will yield better joint strength. Besides, the most influential process parameter has been determined using statistical Analysis of variance (ANOVA). Finally, the comparison of each result has been done for conditions by means percentage of contribution and regression analysis. The general regression equation is formulated and better strength is obtained and it is validated by means of confirmation test. It was observed that value of optimal welded joint strength for both tube without holes and tube with holes are to be 319.485 MPa and 264.825 MPa, respectively.

  20. Horizontal gene transfer in chromalveolates

    Directory of Open Access Journals (Sweden)

    Bhattacharya Debashish

    2007-09-01

    Full Text Available Abstract Background Horizontal gene transfer (HGT, the non-genealogical transfer of genetic material between different organisms, is considered a potentially important mechanism of genome evolution in eukaryotes. Using phylogenomic analyses of expressed sequence tag (EST data generated from a clonal cell line of a free living dinoflagellate alga Karenia brevis, we investigated the impact of HGT on genome evolution in unicellular chromalveolate protists. Results We identified 16 proteins that have originated in chromalveolates through ancient HGTs before the divergence of the genera Karenia and Karlodinium and one protein that was derived through a more recent HGT. Detailed analysis of the phylogeny and distribution of identified proteins demonstrates that eight have resulted from independent HGTs in several eukaryotic lineages. Conclusion Recurring intra- and interdomain gene exchange provides an important source of genetic novelty not only in parasitic taxa as previously demonstrated but as we show here, also in free-living protists. Investigating the tempo and mode of evolution of horizontally transferred genes in protists will therefore advance our understanding of mechanisms of adaptation in eukaryotes.

  1. Horizontal versus vertical plate motions

    Directory of Open Access Journals (Sweden)

    M. Cuffaro

    2006-07-01

    Full Text Available We review both present and past motions at major plate boundaries, which have the horizontal component in average 10 to 100 times faster (10–100 mm/yr than the vertical component (0.01–1 mm/yr in all geodynamic settings. The steady faster horizontal velocity of the lithosphere with respect to the upward or downward velocities at plate boundaries supports dominating tangential forces acting on plates. This suggests a passive role of plate boundaries with respect to far field forces determining the velocity of plates. The forces acting on the lithosphere can be subdivided in coupled and uncoupled, as a function of the shear at the lithosphere base. Higher the asthenosphere viscosity, more significant should be the coupled forces, i.e., the mantle drag and the trench suction. Lower the asthenosphere viscosity, more the effects of uncoupled forces might result determinant, i.e., the ridge push, the slab pull and the tidal drag. Although a combination of all forces acting on the lithosphere is likely, the decoupling between lithosphere and mantle suggests that a torque acts on the lithosphere independently of the mantle drag. Slab pull and ridge push are candidates for generating this torque, but, unlike these boundary forces, the advantage of the tidal drag is to be a volume force, acting simultaneously on the whole plates, and being the decoupling at the lithosphere base controlled by lateral variations in viscosity of the low-velocity layer.

  2. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2004-10-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  3. Planetary plains: subsidence and warping

    Science.gov (United States)

    Kochemasov, G.

    fabric of oceanic floors. Short, medium wave undulations of Pacific's floor (A. Cazenave et al., 1992; D. McAdoo & K. Marks, 1992) present lineations underlining its whole shape. NE lineations predominate on its northern sub-basin, NW lineations on its southern one. They cross at the equatorial zone and together with some other directions give a pattern resembling that observed on the venusian surface. The venusian regional plains typically deformed by wrinkle ridges show interesting similarities to volcanic plains on the Moon and Mars [3]. A subsidence along with warpings can squeeze out some "superfluous" material to surface through planetary scale fissures. This material builds mid-oceanic ridges and huge Hawaii volcano. The Cassini Regio on Iapetus is crossed in the equatorial plain by the dark ridge in some places high 20 km. References: [1] Kochemasov G. G. (2004) Mars and Earth: two dichotomies - one cause. In Workshop on "Hemispheres 1 apart: the origin and modification of the martian crustal dichotomy", LPI Contribution # 1203, Lunar and Planetary Institute, Houston, p. 37. [2] Kochemasov G.G.(1999) Theorems of wave planetary tectonics // Geophys. Res. Abstr. v.1, #3, p.700 . [3] Basilevsky A.T., Head J.W. (2006) Impact craters on regional plains in Venus: Age relations with wrinkle ridges and implications for the geological evolution of Venus // JGR, v.111, EO3006, doi: 10.1029/2005JE002473, 2006. 2

  4. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-01-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  5. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-01-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  6. Tube-Forming Assays.

    Science.gov (United States)

    Brown, Ryan M; Meah, Christopher J; Heath, Victoria L; Styles, Iain B; Bicknell, Roy

    2016-01-01

    Angiogenesis involves the generation of new blood vessels from the existing vasculature and is dependent on many growth factors and signaling events. In vivo angiogenesis is dynamic and complex, meaning assays are commonly utilized to explore specific targets for research into this area. Tube-forming assays offer an excellent overview of the molecular processes in angiogenesis. The Matrigel tube forming assay is a simple-to-implement but powerful tool for identifying biomolecules involved in angiogenesis. A detailed experimental protocol on the implementation of the assay is described in conjunction with an in-depth review of methods that can be applied to the analysis of the tube formation. In addition, an ImageJ plug-in is presented which allows automatic quantification of tube images reducing analysis times while removing user bias and subjectivity.

  7. Chest tube insertion - slideshow

    Science.gov (United States)

    ... presentations/100008.htm Chest tube insertion - series—Normal anatomy To use the sharing features ... pleural space is the space between the inner and outer lining of the lung. It is normally very thin, and lined only ...

  8. Snorkeling and Jones tubes

    OpenAIRE

    Lam, Lewis Y. W.; Weatherhead, Robert G.

    2015-01-01

    We report a case of tympanic membrane rupture during snorkeling in a 17-year-old young man who had previously undergone bilateral Jones tubes placed for epiphora. To our knowledge, this phenomenon has not been previously reported.

  9. Snorkeling and Jones tubes.

    Science.gov (United States)

    Lam, Lewis Y W; Weatherhead, Robert G

    2015-01-01

    We report a case of tympanic membrane rupture during snorkeling in a 17-year-old young man who had previously undergone bilateral Jones tubes placed for epiphora. To our knowledge, this phenomenon has not been previously reported.

  10. Nasogastric feeding tube

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000182.htm Nasogastric feeding tube To use the sharing features on this ... the nose. It can be used for all feedings or for giving a person extra calories. It ...

  11. Ear tube insertion - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100045.htm Ear tube insertion - series—Normal anatomy To use the ... 4 Overview The eardrum (tympanic membrane) separates the ear canal from the middle ear. Review Date 8/ ...

  12. Kinking of medical tubes.

    Science.gov (United States)

    Ingles, David

    2004-05-01

    The phenomenon of kinking in medical tubing remains a problem for some applications, particularly critical ones such as transporting gasses or fluids. Design features are described to prevent its occurrence.

  13. Using a nasogastric tube.

    Science.gov (United States)

    Candy, C

    1986-09-01

    This discussion of the use of a nasogastric tube covers the equipment needed, the method, rehydration and feeding, prolonged nasogastric feeding, and stopping nasogastric feeding. A nasogastric tube is useful when children are unable to drink safely and in sufficient amounts for any of the following reasons: severe dehydration; if intravenous (IV) therapy is unavailable; low birth weight infants; or the child is drowsy or vomiting. Severely malnourished children may be fed initially in this way if they are too weak or anorexic to eat or drink normally. The following equipment is needed: nasogastric tube; lubricating fluid; a syringe; blue litmus paper, if available; adhesive tape; stethoscope if available; and fluid to be given. Explain to the child's parents and the child, if old enough to understand, what will be done; lie infants flat; measure the approximate length from the child's nostril to the ear lobe and then to the top of the abdomen with the tube and mark the position; clean the nostrils to remove the mucus, and lubricate the tip of the tube and gently insert into the nostril; give the child a drink of water if he or she is conscious; continue to pass the tube down until the position marked reaches the nostril; use the syringe to suck up some fluid and test with blue litmus paper to check that the tube is in the stomach; and inject 5-10 ml of fluid (saline or oral rehydration solution, not milk formula) by syringe if satisfied the tube is in the correct position. Where possible, give a continuous drip of fluid. If this is not possible, give frequent small amounts using the syringe as a funnel. If feeding continues for more than 24 hours, clean the nostrils daily with warm water and change the tube to the other nostril every few days. Also keep the mouth very clean with a dilute solution of 8% sodium bicarbonate, if available, or citrus fruit juice. To remove the tube, remove the adhesive tape, take the tube out gently and smoothly, and offer the child a

  14. Magnesium tube hydroforming

    Energy Technology Data Exchange (ETDEWEB)

    Liewald, M.; Pop, R. [Institute for Metal Forming Technology (IFU), Stuttgart (Germany)

    2008-04-15

    Magnesium alloys reveal a good strength-to-weight ratio in the family of lightweight metals and gains potential to provide up to 30% mass savings compared to aluminium and up to 75 % compared to steel. The use of sheet magnesium alloys for auto body applications is however limited due to the relatively low formability at room temperature. Within the scope of this paper, extruded magnesium tubes, which are suitable for hydroforming applications, have been investigated. Results obtained at room temperature using magnesium AZ31 tubes show that circumferential strains are limited to a maximal value of 4%. In order to examine the influence of the forming temperature on tube formability, investigations have been carried out with a new die set for hot internal high pressure (IHP) forming at temperatures up to 400 C. Earlier investigations with magnesium AZ31 tubes have shown that fractures occur along the welding line at tubes extruded over a spider die, whereby a non-uniform expansion at bursting with an elongation value of 24% can be observed. A maximum circumferential strain of approx. 60% could be attained when seamless, mechanically pre-expanded and annealed tubes of the same alloy have been used. The effect of annealing time on materials forming properties shows a fine grained structure for sufficient annealing times as well as deterioration with a large increase at same time. Hence, seamless ZM21 tubes have been used in the current investigations. With these tubes, an increased tensile fracture strain of 116% at 350 C is observed as against 19% at 20 C, obtained by tensile testing of milled specimens from the extruded tubes. This behaviour is also seen under the condition of tool contact during the IHP forming process. To determine the maximum circumferential strain at different forming temperatures and strain rates, the tubes are initially bulged in a die with square cross-section under plane stress conditions. Thereafter, the tubes are calibrated by using an

  15. Power vacuum tubes handbook

    CERN Document Server

    Whitaker, Jerry

    2012-01-01

    Providing examples of applications, Power Vacuum Tubes Handbook, Third Edition examines the underlying technology of each type of power vacuum tube device in common use today. The author presents basic principles, reports on new development efforts, and discusses implementation and maintenance considerations. Supporting mathematical equations and extensive technical illustrations and schematic diagrams help readers understand the material. Translate Principles into Specific Applications This one-stop reference is a hands-on guide for engineering personnel involved in the design, specification,

  16. Aeronautical tubes and pipes

    Science.gov (United States)

    Beauclair, N.

    1984-12-01

    The main and subcomponent French suppliers of aircraft tubes and pipes are discussed, and the state of the industry is analyzed. Quality control is essential for tubes with regard to their i.d. and metallurgical compositions. French regulations do not allow welded seam tubes in hydraulic circuits unless no other form is available, and then rustproofed steel must be installed. The actual low level of orders for any run of tubes dictates that the product is only one of several among the manufacturers' line. Automation, both in NDT and quality control, assures that the tubes meet specifications. A total of 10 French companies participate in the industry, serving both civil and military needs, with some companies specializing only in titanium, steel, or aluminum materials. Concerns wishing to enter the market must upgrade their equipment to meet the higher aeronautical specifications and be prepared to furnish tubes and pipes that serve both functional and structural purposes simultaneously. Additionally, pipe-bending machines must also perform to tight specifications. Pipes can range from 0.2 mm exterior diameter to 40 mm, with wall thicknesses from 0.02 mm to 3 mm. A chart containing a list of manufacturers and their respective specifications and characteristics is presented, and a downtrend in production with reduction of personnel is noted.

  17. A gas laser tube

    Energy Technology Data Exchange (ETDEWEB)

    Tetsuo, F.; Tokhikhide, N.

    1984-04-19

    A gas laser tube is described in which contamination of the laser gas mixture by the coolant is avoided, resulting in a longer service life of the mirrors. The holder contains two tubes, one inside the other. The laser gas mixture flows through the internal tube. An electrode is fastened to the holder. The coolant is pumped through the slot between the two tubes, for which a hole is cut into the holder. The external tube has a ring which serves to seal the cavity containing the coolant from the atmosphere. The internal tube has two rings, one to seal the laser gas mixture and the other to seal the coolant. A slot is located between these two rings, which leads to the atmosphere (the atmosphere layer). With this configuration, the degradation of the sealing properties of the internal ring caused by interaction with the atmospheric layer is not reflected in the purity of the laser gas mixture. Moreover, pollution of the mirrors caused by the penetration of the coolant into the cavity is eliminated.

  18. Dynamic tube/support interaction in heat exchanger tubes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, S.S.

    1991-01-01

    The supports for heat exchanger tubes are usually plates with drilled holes; other types of supports also have been used. To facilitate manufacture and to allow for thermal expansion of the tubes, small clearances are used between tubes and tube supports. The dynamics of tube/support interaction in heat exchangers is fairly complicated. Understanding tube dynamics and its effects is important for heat exchangers. This paper summarizes the current state of the art on this subject and to identify future research needs. Specifically, the following topics are discussed: dynamics of loosely supported tubes, tube/support gap dynamics, tube response in flow, tube damage and wear, design considerations, and future research needs. 55 refs., 1 fig.

  19. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home > NEI YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

  20. Explorando nuevos horizontes en NASA

    Science.gov (United States)

    Villanueva, G. L.

    A pesar de la incesante expansión del Universo iniciada con el Big Bang 14 mil millones de años atrás, nuestro Universo se siente cada día más cercano. La inquebrantable vocación de la humanidad por descubrir nuevos horizontes ha permitido el acercamiento de civilizaciones en nuestro planeta y nos ha permitido conocer nuestro lugar en el Universo como nunca antes. En este artículo presento una breve sinopsis de nuestro trabajo que se relaciona con diversas investigaciones con implicaciones astrobiológicas, desde el origen de los ingredientes de la "sopa de la vida", hasta la evolución y composición de la atmósfera de Marte.

  1. Study of the filtration performance of a plain wave fabric filter using response surface methodology.

    Science.gov (United States)

    Qian, Fuping; Wang, Haigang

    2010-04-15

    The gas-solid two-phase flows in the plain wave fabric filter were simulated by computational fluid dynamics (CFD) technology, and the warps and wefts of the fabric filter were made of filaments with different dimensions. The numerical solutions were carried out using commercial computational fluid dynamics (CFD) code Fluent 6.1. The filtration performances of the plain wave fabric filter with different geometry parameters and operating condition, including the horizontal distance, the vertical distance and the face velocity were calculated. The effects of geometry parameters and operating condition on filtration efficiency and pressure drop were studied using response surface methodology (RSM) by means of the statistical software (Minitab V14), and two second-order polynomial models were obtained with regard to the effect of the three factors as stated above. Moreover, the models were modified by dismissing the insignificant terms. The results show that the horizontal distance, vertical distance and the face velocity all play an important role in influencing the filtration efficiency and pressure drop of the plane wave fabric filters. The horizontal distance of 3.8 times the fiber diameter, the vertical distance of 4.0 times the fiber diameter and Reynolds number of 0.98 are found to be the optimal conditions to achieve the highest filtration efficiency at the same face velocity, while maintaining an acceptable pressure drop.

  2. Validation of a Model for Ice Formation around Finned Tubes

    OpenAIRE

    Kamal A. R. Ismai; Fatima A. M. Lino

    2016-01-01

    Phase change materials although attaractive option for thermal storage applications its main drawback is the slow thermal response during charging and discharging processes due to their low thermal conductivity. The present study validates a model developed by the authors some years ago on radial fins as a method to meliorate the thermal performance of PCM in horizontal storage system. The developed model for the radial finned tube is based on pure conduction, the enthalpy approach and was di...

  3. Whillans Ice Plain Stick Slip

    Science.gov (United States)

    Lipovsky, B.; Dunham, E. M.

    2015-12-01

    Concern about future sea level rise motivates the study of fast flowing ice. The Whillans Ice Plain (WIP) region of the West Antarctic Ice Sheet is notable for decelerating from previously fast motion during the instrumental record. Since most ice flux in Antarctica occurs through ice streams, understanding the conditions that cause ice stream stagnation is of basic importance in understanding the continent's contribution to future sea level rise. Although recent progress has been made in understanding the relationship between basal conditions and ice stream motion, direct observation of the temporal variation in subglacial conditions during ice stream stagnation has remained elusive. The Whillans Ice Plain flows to the sea mostly by way of stick-slip motion. We present numerical simulations of this stick-slip motion that capture the inertial dynamics, seismic waves, and the evolution of sliding with rate- and state-dependent basal friction. Large scale stick-slip behavior is tidally modulated and encompasses the entire WIP. Sliding initiates within one of several locked regions and then propagates outward with low average rupture velocity (~ 200 m/s). Sliding accelerates over a period of 200 s attain values as large as 65 m/d. From Newton's second law, this acceleration is ~ T / (rho H) for average shear stress drop T, ice thickness H, and ice density rho. This implies a 3 Pa stress drop that must be reconciled with the final stress drop of 300 Pa inferred from the total slip and fault dimensions. A possible explanation of this apparent discrepancy is that deceleration of the ice is associated with a substantial decrease in traction within rate-strengthening regions of the bed. During these large-scale sliding events, m-scale patches at the bed produce rapid (20 Hz) stick-slip motion. Each small event occurs over ~ 1/100 s, produces ~ 40 microns of slip, and gives rise to a spectacular form of seismic tremor. Variation between successive tremor episodes allows us

  4. On the heat transfer in the pool boiling at tightly finned steel tubes; Zum Waermeuebergang beim Behaeltersieden an eng berippten Stahlrohren

    Energy Technology Data Exchange (ETDEWEB)

    Bujok, Patrick; Wang, Yabai; Luke, Andrea [Kassel Univ. (Germany). Lehrstuhl fuer Technische Thermodynamik

    2012-07-01

    Process-integrated energy efficiency in power plants and process plants can only be achieved with new innovative apparatus concepts. There exist no sufficient reference applications, no data to assist in interpretation a well as no certificates of operational safety for these apparatus concepts. Thus, these concepts are not applied despite of the significant energetic advantages. Under this aspect, industrial companies (plant fabricators, plant operators and engineering offices) and five universities have affiliated to a multi-institutional project in order to explore unused opportunities on the integration of heat. The Department of Technical Thermodynamics at the University of Kassel (Federal Republic of Germany) regards to apparatuses which effectively and securely transfer a heat flow at especially low differences of temperatures between the heat dissipating and heat absorbing side of an evaporator with structured ducts. It has been known for many decades that ribbed structures are one of the most efficient methods to transfer heat. Ribbed ducts in heat exchangers are used in the refrigeration technology as well as in the technology of air conditioning. Nevertheless, plain tubes still are the technical standard in the chemical and process industry. The objective of this research project consists of a presentation of macrostructures and microstructures which can be produced efficiently with regard to the heat transfer, at a relatively low cost as well as in large quantities with a consistent structure. Furthermore, a substantial database for the design of evaporators with such surface textures is set up. Thus, evaporators being produced by the project partner Wieland-Werke AG (Ulm, Federal Republic of Germany) were investigated on a laboratory scale as well as in small tube bundles. Subsequently, selected structures were applied in the technical centre of the project partner Linde AG (Pullach, Federal Republic of Germany) in order to validate the transferability

  5. Optimization of horizontal well staggered patterns

    Institute of Scientific and Technical Information of China (English)

    Zhao Chunsen; Li Peijing; Guan Dan; Liu Qingjuan

    2008-01-01

    Staggered line-drive patterns are widely used in oilfields. In this paper, to optimize a staggered pattern of horizontal wells, a 3D problem was divided into two 2D (x-y plane and y-z plane) problems with the pseudo-3D method, conformal transformation and superposition principle. A productivity equation for a horizontal well was deduced, which can be used to optimize the well pattern. A relationship between the length of horizontal wells and the shape factor of well patterns was established. The result shows that optimized well patterns can improve oil production from horizontal wells. This provides a theoretical basis for horizontal well applications to the development of oilfieids, especially for overall development of oilfields by horizontal wells.

  6. Preliminary design of the Carrisa Plains solar central receiver power plant. Volume III, Book 3. Appendices, Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Mouradian, E. M.

    1983-12-31

    Thermal analyses for the preliminary design phase of the Receiver of the Carrizo Plains Solar Power Plant are presented. The sodium reference operating conditions (T/sub in/ = 610/sup 0/F, T/sub out/ = 1050/sup 0/F) have been considered. Included are: Nominal flux distribution on receiver panal, Energy input to tubes, Axial temperature distribution; sodium and tubes, Sodium flow distribution, Sodium pressure drop, orifice calculations, Temperature distribution in tube cut (R-0), Backface structure, and Nonuniform sodium outlet temperature. Transient conditions and panel front face heat losses are not considered. These are to be addressed in a subsequent design phase. Also to be considered later are the design conditions as variations from the nominal reference (operating) condition. An addendum, designated Appendix C, has been included describing panel heat losses, panel temperature distribution, and tube-manifold joint thermal model.

  7. Hydrology and digital simulation of the regional aquifer system, eastern Snake River Plain, Idaho

    Science.gov (United States)

    Garabedian, S.P.

    1992-01-01

    The occurrence and movement of water in the regional aquifer system that underlies the eastern Snake River Plain, Idaho, de- pend on the transmissivity and storage capacity of rocks that compose the geologic framework and on the distribution and amount of recharge and discharge of water within that frame- work. On a regional scale, most water moves horizontally through interflow zones in Quaternary basalt of the Snake River Group. In recharge and discharge areas, water also moves vertically along joints and interfingering edges of basalt flows. Aquifer thickness is largely unknown, but geophysical studies suggest that locally the Quaternary basalt may exceed several thousand feet. Along the margins of the plain, sand and gravel several hundred feet thick transmit large volumes of water.

  8. Effect of tube size on electromagnetic tube bulging

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The commercial finite code ANSYS was employed for the simulation of the electromagnetic tube bulging process. The finite element model and boundary conditions were thoroughly discussed. ANSYS/EMAG was used to model the time varying electromagnetic field in order to obtain the radial and axial magnetic pressure acting on the tube. The magnetic pressure was then used as boundary conditions to model the high velocity deformation of various length tube with ANSYS/LSDYNA. The time space distribution of magnetic pressure on various length tubes was presented. Effect of tube size on the distribution of radial magnetic pressure and axial magnetic pressure and high velocity deformation were discussed. According to the radial magnetic pressure ratio of tube end to tube center and corresponding dimensionless length ratio of tube to coil, the free electromagnetic tube bulging was studied in classification. The calculated results show good agreements with practice.

  9. EFFECT OF SURFACTANT ON TWO-PHASE FLOW PATTERNS OF WATER-GAS IN CAPILLARY TUBES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Flow patterns of liquid-gas two-phase flow were experimentally investigated. The experiments were carried out in both vertical and horizontal capillary tubes having inner diameters of 1.60 mm. The working liquid was the mixture of water and Sodium Dodecyl Benzoyl Sulfate (SDBS). The working gas was Nitrogen. For the water/SDBS mixture-gas flow in the vertical capillary tube, flow-pattern transitions occurred at lower flow velocities than those for the water-gas flow in the same tube. For the water/SDBS mixture-gas flow in the horizontal capillary tube, surface tension had little effect on the bubbly-intermittent transition and had only slight effect on the plug-slug and slug-annular transitions. However, surface tension had significant effect on the wavy stratified flow regime. The wavy stratified flow regime of water/SDBS mixture-gas flow expanded compared with that of water-gas.

  10. Categorising YouTube

    Directory of Open Access Journals (Sweden)

    Thomas Mosebo Simonsen

    2011-09-01

    Full Text Available This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC of YouTube. The article investigates the construction of navigationprocesses on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within the interacting relationship of new and old genres are discussed. It is argued that the utility of a conventional categorical system is primarily of analytical and theoretical interest rather than as a practical instrument.

  11. 44 CFR 10.14 - Flood plains and wetlands.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Flood plains and wetlands. 10... Flood plains and wetlands. For any action taken by FEMA in a flood plain or wetland, the provisions of... Executive Order 11988, Flood Plain Management, and Executive Order 11990, Protection of Wetlands (44...

  12. Southern Great Plains Atmospheric Radiation Measurement Site

    Data.gov (United States)

    Federal Laboratory Consortium — The Southern Great Plains Atmospheric Radiation Measurement Site (SGP-ARM) is the oldest and largest of DOE's Arm sites. It was established in 1992. It consists of...

  13. Tracheostomy tubes and related appliances.

    Science.gov (United States)

    Hess, Dean R

    2005-04-01

    Tracheostomy tubes are used to administer positive-pressure ventilation, to provide a patent airway, to provide protection from aspiration, and to provide access to the lower respiratory tract for airway clearance. They are available in a variety of sizes and styles, from several manufacturers. The dimensions of tracheostomy tubes are given by their inner diameter, outer diameter, length, and curvature. Differences in length between tubes of the same inner diameter, but from different manufacturers, are not commonly appreciated but may have important clinical implications. Tracheostomy tubes can be angled or curved, a feature that can be used to improve the fit of the tube in the trachea. Extra proximal length tubes facilitate placement in patients with large necks, and extra distal length tubes facilitate placement in patients with tracheal anomalies. Several tube designs have a spiral wire reinforced flexible design and have an adjustable flange design to allow bedside adjustments to meet extra-length tracheostomy tube needs. Tracheostomy tubes can be cuffed or uncuffed. Cuffs on tracheostomy tubes include high-volume low-pressure cuffs, tight-to-shaft cuffs, and foam cuffs. The fenestrated tracheostomy tube has an opening in the posterior portion of the tube, above the cuff, which allows the patient to breathe through the upper airway when the inner cannula is removed. Tracheostomy tubes with an inner cannula are called dual-cannula tracheostomy tubes. Several tracheostomy tubes are designed specifically for use with the percutaneous tracheostomy procedure. Others are designed with a port above the cuff that allows for subglottic aspiration of secretions. The tracheostomy button is used for stoma maintenance. It is important for clinicians caring for patients with a tracheostomy tube to understand the nuances of various tracheostomy tube designs and to select a tube that appropriately fits the patient.

  14. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Lisa S. Botnen

    2005-07-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership characterization work is nearing completion, and most remaining efforts are related to finalizing work products. Task 2 (Technology Deployment) has developed a Topical Report entitled ''Deployment Issues Related to Geologic CO{sub 2} Sequestration in the PCOR Partnership Region''. Task 3 (Public Outreach) has developed an informational Public Television program entitled ''Nature in the Balance'', about CO{sub 2} sequestration. The program was completed and aired on Prairie Public Television in this quarter. Task 4 (Sources, Sinks, and Infrastructure) efforts are nearing completion, and data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation are being incorporated into a series of topical reports. The expansion of the Decision Support System Geographic Information System database has continued with the development of a ''save bookmark'' feature that allows users to save a map from the system easily. A feature that allows users to develop a report that summarizes CO{sub 2} sequestration parameters was also developed. Task 5 (Modeling and Phase II Action Plans) focused on screening and qualitatively assessing sequestration options and developing economic estimates for important regional CO{sub 2} sequestration strategies.

  15. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-04-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) and provided information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 2 efforts also included preparation of a draft topical report entitled ''Deployment Issues Related to Geologic CO{sub 2} Sequestration in the PCOR Partnership Region'', which is nearing completion. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. The video will be completed and aired on Prairie Public Television in the next quarter. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. The addition of the Canadian province of Alberta to the PCOR Partnership region expanded the decision support system (DSS) geographic information system database. Task 5 screened and qualitatively assessed sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  16. 3D-Printed Broadband Dielectric Tube Terahertz Waveguide with Anti-Reflection Structure

    Science.gov (United States)

    Vogt, Dominik Walter; Leonhardt, Rainer

    2016-07-01

    We demonstrate broadband, low loss, and close-to-zero dispersion guidance of terahertz (THz) radiation in a dielectric tube with an anti-reflection structure (AR-tube waveguide) in the frequency range from 0.2 to 1.0 THz. The anti-reflection structure (ARS) consists of close-packed cones in a hexagonal lattice arranged on the outer surface of the tube cladding. The feature size of the ARS is in the order of the wavelength between 0.2 and 1.0 THz. The waveguides are fabricated with the versatile and cost efficient 3D-printing method. Terahertz time-domain spectroscopy (THz-TDS) measurements as well as 3D finite-difference time-domain simulations (FDTD) are performed to extensively characterize the AR-tube waveguides. Spectrograms, attenuation spectra, effective phase refractive indices, and the group-velocity dispersion parameters β 2 of the AR-tube waveguides are presented. Both the experimental and numerical results confirm the extended bandwidth and smaller group-velocity dispersion of the AR-tube waveguide compared to a low loss plain dielectric tube THz waveguide. The AR-tube waveguide prototypes show an attenuation spectrum close to the theoretical limit given by the infinite cladding tube waveguide.

  17. Numerical simulation of fluid flow and heat transfer in enhanced copper tube

    Science.gov (United States)

    Rahman, M. M.; Zhen, T.; Kadir, A. K.

    2013-06-01

    Inner grooved tube is enhanced with grooves by increasing the inner surface area. Due to its high efficiency of heat transfer, it is used widely in power generation, air conditioning and many other applications. Heat exchanger is one of the example that uses inner grooved tube to enhance rate heat transfer. Precision in production of inner grooved copper tube is very important because it affects the tube's performance due to various tube parameters. Therefore, it is necessary to carry out analysis in optimizing tube performance prior to production in order to avoid unnecessary loss. The analysis can be carried out either through experimentation or numerical simulation. However, experimental study is too costly and takes longer time in gathering necessary information. Therefore, numerical simulation is conducted instead of experimental research. Firstly, the model of inner grooved tube was generated using SOLIDWORKS. Then it was imported into GAMBIT for healing, followed by meshing, boundary types and zones settings. Next, simulation was done in FLUENT where all the boundary conditions are set. The simulation results were observed and compared with published experimental results. It showed that heat transfer enhancement in range of 649.66% to 917.22% of inner grooved tube compared to plain tube.

  18. 3D-Printed Broadband Dielectric Tube Terahertz Waveguide with Anti-Reflection Structure

    Science.gov (United States)

    Vogt, Dominik Walter; Leonhardt, Rainer

    2016-11-01

    We demonstrate broadband, low loss, and close-to-zero dispersion guidance of terahertz (THz) radiation in a dielectric tube with an anti-reflection structure (AR-tube waveguide) in the frequency range from 0.2 to 1.0 THz. The anti-reflection structure (ARS) consists of close-packed cones in a hexagonal lattice arranged on the outer surface of the tube cladding. The feature size of the ARS is in the order of the wavelength between 0.2 and 1.0 THz. The waveguides are fabricated with the versatile and cost efficient 3D-printing method. Terahertz time-domain spectroscopy (THz-TDS) measurements as well as 3D finite-difference time-domain simulations (FDTD) are performed to extensively characterize the AR-tube waveguides. Spectrograms, attenuation spectra, effective phase refractive indices, and the group-velocity dispersion parameters β 2 of the AR-tube waveguides are presented. Both the experimental and numerical results confirm the extended bandwidth and smaller group-velocity dispersion of the AR-tube waveguide compared to a low loss plain dielectric tube THz waveguide. The AR-tube waveguide prototypes show an attenuation spectrum close to the theoretical limit given by the infinite cladding tube waveguide.

  19. Numerical Analysis of Mixed Convection through an Internally Finned Tube

    Directory of Open Access Journals (Sweden)

    Sachindra Kumar Rout

    2012-01-01

    Full Text Available Wall temperature of an internally finned tube has been computed numerically for different fin number, height, and shape by solving conservation equations of mass, momentum, and energy using Fluent 12.1 for a steady and laminar flow of fluid inside a tube under mixed flow condition. It has been found that there exists an optimum number for fins to keep the pipe wall temperature at a minimum. The fin height has an optimum value beyond which the wall temperature becomes insensitive to fin height. For a horizontal tube, under mixed flow condition, it is seen that the upper surface has higher average temperature than the lower surface. The impact of fin shape on the heat transfer rate shows that wall temperature is least for triangular-shaped fins, compared to rectangular- and T-shaped fins. In addition to the thermal characteristics, the pressure drop caused due to the presence of fins has also been studied.

  20. Widespread horizontal transfer of retrotransposons.

    Science.gov (United States)

    Walsh, Ali Morton; Kortschak, R Daniel; Gardner, Michael G; Bertozzi, Terry; Adelson, David L

    2013-01-15

    In higher organisms such as vertebrates, it is generally believed that lateral transfer of genetic information does not readily occur, with the exception of retroviral infection. However, horizontal transfer (HT) of protein coding repetitive elements is the simplest way to explain the patchy distribution of BovB, a long interspersed element (LINE) about 3.2 kb long, that has been found in ruminants, marsupials, squamates, monotremes, and African mammals. BovB sequences are a major component of some of these genomes. Here we show that HT of BovB is significantly more widespread than believed, and we demonstrate the existence of two plausible arthropod vectors, specifically reptile ticks. A phylogenetic tree built from BovB sequences from species in all of these groups does not conform to expected evolutionary relationships of the species, and our analysis indicates that at least nine HT events are required to explain the observed topology. Our results provide compelling evidence for HT of genetic material that has transformed vertebrate genomes.

  1. On the Hydraulics of Flowing Horizontal Wells

    Science.gov (United States)

    Bian, A.; Zhan, H.

    2003-12-01

    A flowing horizontal well is a special type of horizontal well that does not have pumping/injecting facility. The discharge rate of a flowing horizontal well is controlled by the hydraulic gradient between the aquifer and the well and it generally varies with time if the hydraulic head of the aquifer is transient. This type of well has been used in landslide control, mining dewatering, water table control, underground water transportation through a horizontal tunnel, agricultural water drainage, and other applications. Flowing horizontal wells have quite different hydrodynamic characteristics from horizontal wells with fixed pumping or injecting rates because their discharge rates are functions of the aquifer hydraulic heads (Zhan et al, 2001; Zhan and Zlotnik, 2002). Hydraulics of flowing horizontal wells have rarely been studied although the hydraulics of flowing vertical wells have been extensively investigated before. The purpose of this paper is to obtain analytical solutions of groundwater flow to a flowing horizontal-well in a confined aquifer, in a water table aquifer without precipitation, and in a water table aquifer with precipitation. The functions of the flowing horizontal well discharge rates versus time will be obtained under above mentioned different aquifer conditions. The relationships of the aquifer hydraulic heads versus the discharge rates of the well will be investigated. The rate of water table decline due to the dewatering of the well will also be computed, and this solution is particularly useful for landslide control and mining dewatering. The theoretical solutions will be compared with results of experiments that will be conducted in the hydrological laboratory at Texas A&M University. Reference: Zhan, H., Wang, L.V., and Park, E, On the horizontal well pumping tests in the anisotropic confined aquifers, J. hydrol., 252, 37-50, 2001. Zhan, H., and Zlotnik, V. A., Groundwater flow to a horizontal or slanted well in an unconfined aquifer

  2. Fatigue Life Prediction of Horizontal Press Frame Based on Statistical Probability and Its Redesign

    Institute of Scientific and Technical Information of China (English)

    WeiWei Zhang; XiaoSon Wang; Bo Yang; Shi-Jian Yuan

    2014-01-01

    Horizontal press as an important part of hydro-forming machine is used to output the horizontal force to keep the high internal pressure during tube hydro-forming. However, the horizontal press frame is usually mounted on the press bed and not pre-stressed. Meanwhile it will be subjected to the reaction force caused by liquid pressure. Stresses are concentrated severely on the assemble region due to deformation, and total fatigue life will decrease. In order to predict the total fatigue life of the frame, the simulations are used firstly to determine to stress concentration region, and then strain gauge measurements are carried out under different loads. Next, the methods of statistical probability are conducted to calculate the fatigue life based on long-term load history. Finally a structure with the considerable longer fatigue life is redesigned.

  3. Horizontal Heat Exchanger Design and Analysis for Passive Heat Removal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Vierow, Karen

    2005-08-29

    This report describes a three-year project to investigate the major factors of horizontal heat exchanger performance in passive containment heat removal from a light water reactor following a design basis accident LOCA (Loss of Coolant Accident). The heat exchanger studied in this work may be used in advanced and innovative reactors, in which passive heat removal systems are adopted to improve safety and reliability The application of horizontal tube-bundle condensers to passive containment heat removal is new. In order to show the feasibility of horizontal heat exchangers for passive containment cooling, the following aspects were investigated: 1. the condensation heat transfer characteristics when the incoming fluid contains noncondensable gases 2. the effectiveness of condensate draining in the horizontal orientation 3. the conditions that may lead to unstable condenser operation or highly degraded performance 4. multi-tube behavior with the associated secondary-side effects This project consisted of two experimental investigations and analytical model development for incorporation into industry safety codes such as TRAC and RELAP. A physical understanding of the flow and heat transfer phenomena was obtained and reflected in the analysis models. Two gradute students (one funded by the program) and seven undergraduate students obtained research experience as a part of this program.

  4. Experimental verification of the horizontal steam generator boil-off transfer degradation at natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Hyvaerinen, J. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland); Kouhia, J. [VTT Energy, Lappeenranta (Finland)

    1997-12-31

    The presentation summarises the highlights of experimental results obtained for VVER type horizontal steam generator heat transfer, primary side flow pattern, and mixing in the hot collector during secondary side boil-off with primary at single-phase natural circulation. The experiments were performed using the PACTEL facility with Large Diameter (LD) steam generator models, with collector instrumentation designed specifically for these tests. The key findings are as follows: (1) the primary to secondary heat transfer degrades as the secondary water inventory is depleted, following closely the wetted tube area; (2) a circulatory flow pattern exists in the tube bundle, resulting in reversed flow (from cold to the hot collector) in the lower part of the tube bundle, and continuous flow through the upper part, including the tubes that have already dried out; and (3) mixing of the hot leg flow entering the hot collector and reversed, cold, tube flow remains confined within the collector itself, extending only a row or two above the elevation at which tube flow reversal has taken place. 6 refs.

  5. Heat-shrink plastic tubing seals joints in glass tubing

    Science.gov (United States)

    Del Duca, B.; Downey, A.

    1968-01-01

    Small units of standard glass apparatus held together by short lengths of transparent heat-shrinkable polyolefin tubing. The tubing is shrunk over glass O-ring type connectors having O-rings but no lubricant.

  6. Horizontal Directional Drilling (HDD) Technology and Applications

    Institute of Scientific and Technical Information of China (English)

    J. G. Cai; X. N. Wang

    2004-01-01

    @@ 1 What is Horizontal Directional Drilling? Horizontal Directional Drilling, accurately steered drilling, has become state -of- the -art drilling technique in the world. Specially- designed directionsteerable corebarrel and accurate direction measurement tool are available for the use together with wire line core drilling machine. That makes it feasible to extract cores and to measure the drill travel line &length while drilling in a curve.

  7. Importance of drill string assembly swivel in horizontal drilling

    Directory of Open Access Journals (Sweden)

    Edmund Tasak

    2006-10-01

    Full Text Available A part of the drill string – the swivel (rotational connector – accomplishes an important task in the horizontal drilling. Its malfunctioning makes it impossible to draw in ( install large diameter and length pipelines. The causes of the connector break-down during the horizontal drilling are investigated in the paper. The drilling has been made for twenty inches gas pipeline installation during reaming operations. A trouble was encountered making good work conditions of a system consisting of the drilling machine drill string reamer swivel tube shield of Cardan joint and the gas pipeline 500 m long. In this case, the swivel brokes down and the planned operation was not finished. The assessment of improper drilling conditions, selection of operation system components, and drilling parameters and the insufficient technological supervising have created an excessive risk of failure. A proper application of technical analysis would considerably decrease the hazard of failure which cause large costs, delays and decrease of confidence to the drilling contractor and pipeline installation.

  8. An experimental investigation on the airside performance of fin-and-tube heat exchangers having slit fins under wet condition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nae Hyun [Incheon National University, Incheon (Korea, Republic of); Kim, Tae Hun [Samsung Electronics Co., Suwon (Korea, Republic of)

    2015-11-15

    In this study, the heat transfer and friction characteristics of the 5.3 mm O.D. slit-finned heat exchangers under wet condition have been experimentally investigated. Plain-finned heat exchangers having the same 5.3 mm O.D. tubes are also tested for comparison purpose. The effect of fin pitch on j and f factor is negligible. Slit fin samples yield higher j and f factors than plain fin samples. For one row configuration, the average f factor ratio between slit fin sample and plain fin sample is 2.18. The ratio increases to 2.41 for two row configuration, and to 2.65 for three row configuration. As for the j factor, the ratios are approximately the same (1.61, 1.70 and 1.71 for one, two and three row configuration). Both j and f factor increase as the number of tube row decreases. The same trend is observed for the plain fin samples. At high Reynolds numbers, the j/f ratios of the slit fin are approximately the same as those of the plain fin. At low Reynolds numbers, the j/f ratios of the slit fin are smaller than those of plain fin. Data are compared with existing correlations.

  9. PACTEL: Experiments on the behaviour of the new horizontal steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Kouhia, J.; Riikonen, V.; Purhonen, H. [VTT Energy, Lappeenranta (Finland)

    1995-12-31

    Experiments were performed to study the behaviour of the PACTEL facility, a medium scale integral test loop simulating VVER 440 pressurized water reactors. The study focused on the operation of the new horizontal steam generator model installed in PACTEL. Three experiments were conducted: a small-break test to observe the steam generator behaviour over a range of primary coolant inventories, a hot leg loop seal experiment to study the cyclic behaviour of a loop seal and a loss of secondary side feedwater test to examine the effect of uncovered tubes in the steam generator. A reverse flow was observed in the lower part of the U-tube bundle of the steam generator during natural circulation. The flow reversal point dropped when the tubes uncovered, during secondary inventory reduction. (orig.). 5 refs.

  10. Downhole pulse tube refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.; Gardner, D. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group

    1997-12-01

    This report summarizes a preliminary design study to explore the plausibility of using pulse tube refrigeration to cool instruments in a hot down-hole environment. The original motivation was to maintain Dave Reagor`s high-temperature superconducting electronics at 75 K, but the study has evolved to include three target design criteria: cooling at 30 C in a 300 C environment, cooling at 75 K in a 50 C environment, cooling at both 75 K and 30 C in a 250 C environment. These specific temperatures were chosen arbitrarily, as representative of what is possible. The primary goals are low cost, reliability, and small package diameter. Pulse-tube refrigeration is a rapidly growing sub-field of cryogenic refrigeration. The pulse tube refrigerator has recently become the simplest, cheapest, most rugged and reliable low-power cryocooler. The authors expect this technology will be applicable downhole because of the ratio of hot to cold temperatures (in absolute units, such as Kelvin) of interest in deep drilling is comparable to the ratios routinely achieved with cryogenic pulse-tube refrigerators.

  11. The thermal tube

    Energy Technology Data Exchange (ETDEWEB)

    Semena, M.G.

    1980-08-30

    A thermal tube is proposed which contains a layer of dielectric, capillary porous material located on the internal surface of the body. To increase the heat transmitting capability, the layer of capillary porous material is made in the form of a felting, formed by hollow fibers from a non-alkaline, borosilicate glass.

  12. Prawns in Bamboo Tube

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Ingredients: 400 grams Jiwei prawns, 25 grams pork shreds, 5 grams sliced garlic. Condiments: 5 grams cooking oil, minced ginger root and scallions, cooking wine, salt, pepper and MSG (optional) Method: 1. Place the Shelled prawns into a bowl and mix with all the condiments. 2. Stuff the prawns into a fresh bamboo tube,

  13. Cladding tube manufacturing technology

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, R. [Kraftwerk Union AG, Mulheim (Germany); Jeong, Y.H.; Baek, B.J.; Kim, K.H.; Kim, S.J.; Choi, B.K.; Kim, J.M. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1999-04-01

    This report gives an overview of the manufacturing routine of PWR cladding tubes. The routine essentially consists of a series of deformation and annealing processes which are necessary to transform the ingot geometry to tube dimensions. By changing shape, microstructure and structure-related properties are altered simultaneously. First, a short overview of the basics of that part of deformation geometry is given which is related to tube reducing operations. Then those processes of the manufacturing routine which change the microstructure are depicted, and the influence of certain process parameters on microstructure and material properties are shown. The influence of the resulting microstructure on material properties is not discussed in detail, since it is described in my previous report 'Alloy Development for High Burnup Cladding.' Because of their paramount importance still up to now, and because manufacturing data and their influence on properties for other alloys are not so well established or published, the descriptions are mostly related to Zry4 tube manufacturing, and are only in short for other alloys. (author). 9 refs., 46 figs.

  14. Misdirected Minitracheostomy Tube

    Science.gov (United States)

    Singh, Ajmer; Nanda, Chinmaya; Mehta, Yatin

    2017-01-01

    We report a patient who after an uneventful coronary artery bypass graft surgery and left ventricular aneurysmorrhaphy developed intracerebral hemorrhage and subsequently required minitracheostomy. Chest X-ray showed misdirected minitracheostomy tube facing upward toward the laryngeal opening which was repositioned using bronchoscope. PMID:28074805

  15. Misdirected minitracheostomy tube

    Directory of Open Access Journals (Sweden)

    Ajmer Singh

    2017-01-01

    Full Text Available We report a patient who after an uneventful coronary artery bypass graft surgery and left ventricular aneurysmorrhaphy developed intracerebral hemorrhage and subsequently required minitracheostomy. Chest X-ray showed misdirected minitracheostomy tube facing upward toward the laryngeal opening which was repositioned using bronchoscope.

  16. Application of flood index in monitoring Flood-plain ecosystems (by the example of the Middle Ob flood-plain)

    OpenAIRE

    Bolotnov, V. P.

    2007-01-01

    The concept of regional hydroecological monitoring has been developed for the flood-plain of the Middle Ob. Its object is to control the state of flood-plain ecosystem productivity for organization of scientific, regional-adopted and ecologically regulated nature management. For this purpose hydroecological zoning of flood-plain territory performed, the most representative stations of water-gauge observations for each flood-plain zone organized, the scheme of flood-plain flooding was prepared...

  17. Intra-firm Horizontal Knowledge Transfer Management

    Institute of Scientific and Technical Information of China (English)

    WANG Yaowu; WANG Yanhang

    2009-01-01

    Knowledge transfer is widely emphasized as a strategic issue for firm competition. A model for intra-firm horizontal knowledge transfer is proposed to model horizontal knowledge transfer to solve some demerits in current knowledge transfer researches. The concept model of intra-firm horizontal knowledge transfer was described and a framework was provided to define the main components of thetransfer process. Horizontal knowledge transfer is that knowledge is transferred from the source to the same hierarchical level recipients as the target. Horizontal knowledge transfer constitutes a strategic area of knowledge management research. However, little is known about the circumstances under which one particular mechanism is the most appropriate. To address these issues, some significant conclusions are drawn concerning knowledge transfer mechanisms in a real-world setting.

  18. Geologic Map of the Santa Barbara Coastal Plain Area, Santa Barbara County, California

    Science.gov (United States)

    Minor, Scott A.; Kellogg, Karl S.; Stanley, Richard G.; Gurrola, Larry D.; Keller, Edward A.; Brandt, Theodore R.

    2009-01-01

    This report presents a newly revised and expanded digital geologic map of the Santa Barbara coastal plain area at a compilation scale of 1:24,000 (one inch on the map to 2,000 feet on the ground)1 and with a horizontal positional accuracy of at least 20 m. The map depicts the distribution of bedrock units and surficial deposits and associated deformation underlying and adjacent to the coastal plain within the contiguous Dos Pueblos Canyon, Goleta, Santa Barbara, and Carpinteria 7.5' quadrangles. The new map supersedes an earlier preliminary geologic map of the central part of the coastal plain (Minor and others, 2002; revised 2006) that provided coastal coverage only within the Goleta and Santa Barbara quadrangles. In addition to new mapping to the west and east, geologic mapping in parts of the central map area has been significantly revised from the preliminary map compilation - especially north of downtown Santa Barbara in the Mission Ridge area - based on new structural interpretations supplemented by new biostratigraphic data. All surficial and bedrock map units, including several new units recognized in the areas of expanded mapping, are described in detail in the accompanying pamphlet. Abundant new biostratigraphic and biochronologic data based on microfossil identifications are presented in expanded unit descriptions of the marine Neogene Monterey and Sisquoc Formations. Site-specific fault kinematic observations embedded in the digital map database are more complete owing to the addition of slip-sense determinations. Finally, the pamphlet accompanying the present report includes an expanded and refined summary of stratigraphic and structural observations and interpretations that are based on the composite geologic data contained in the new map compilation. The Santa Barbara coastal plain is located in the western Transverse Ranges physiographic province along an east-west-trending segment of the southern California coastline about 100 km (62 mi) northwest

  19. Numerical Analysis of Tube-Fin Heat Exchanger using Fluent

    Directory of Open Access Journals (Sweden)

    M. V. Ghori

    2012-08-01

    Full Text Available Three-dimensional CFD simulations are carried out to investigate heat transfer and fluid flow characteristics of two-row plain Tube and Fin heat exchanger using FLUENT software. Heat transfer and pressure drop characteristics of the heat exchanger are investigated for Reynolds numbers ranging from 330 to 7000. Model geometry is created and meshed by using GAMBIT software. Fluid flow and heat transfer are simulated and results compared using both laminar and turbulent flow models k-, and SST k-omega, with steady-state solvers to calculate pressure drop, flow, and temperature fields. Model validation is carried out by comparing the simulated value friction factor f and Colburn factor j to experimental results investigate by Wang. Reasonable agreement is found between the simulations and experimental data, and the fluent software has been sufficient for simulating the flow fields in tube-fin heat exchangers.

  20. Horizontal Canal Benign Positional Vertigo

    Directory of Open Access Journals (Sweden)

    Mohtaram Najafi

    1998-03-01

    Full Text Available Benign paroxysmal positional vertigo (BPPV is a syndrome characterized by transient episodes of vertigo in association with rapid changes in head position in Dix-Halpike Maneuver. This kind of vertigo is thought to be caused by migration of otoconial debris into canals other than the posterior canal, such as the anterior or lateral canals. It is also theoretically possible for many aberrant patterns of BPPV to occur from an interaction of debris in several canals, location of debris within the canal, and central adaptation patterns to lesions. The symptoms of BPPV are much more consistent with free-moving densities (canaliths in the posterior SCC rather than fixed densities attached to the cupula. While the head is upright, the particles sit in the PSC at the most gravity-dependent position. The best method to induce and see vertigo and nystagmus in BPPV of the lateral semicircular canal is to rotate head 90°while patient is in the supine position, nystagmus would appear in the unaffected side weaker but longer than the affected side. canal paresis has been described in one third of the patients with BPPV. Adaptation which is one of the remarkable features of BPPV in PSC is rarely seen in LSC. Rotations of 270° or 360° around the yaw axis (the so-called barbecue maneuver toward the unaffected ear are popular methods for the treatment of geotropic HC-BPPV. These maneuvers consist of sequential head turning of 90° toward the healthy side while supine. With these maneuvers, the free-floating otoconial debris migrates in the ampullofugal direction, finally entering the utricle through the nonampullated end of the horizontal canal. This kind of vertigo recovers spontaneously more rapidly and suddenly.

  1. Restore condition of Incore thimble tubes in guide tubes

    Energy Technology Data Exchange (ETDEWEB)

    Solanas, A.; Izquierdo, J.

    2014-07-01

    Aging of Nuclear Power Plant and succession of outages lead to wear and twist of the thimbles tubes but also to the fooling of Incore guide tubes. These can create friction and a high strength must be used for thimble tubes withdrawal. (Author)

  2. Eustachian tube function in children after insertion of ventilation tubes.

    NARCIS (Netherlands)

    Heerbeek, N. van; Ingels, K.J.A.O.; Snik, A.F.M.; Zielhuis, G.A.

    2001-01-01

    This study was performed to assess the effect of the insertion of ventilation tubes and the subsequent aeration of the middle ear on eustachian tube (ET) function in children. Manometric ET function tests were performed repeatedly for 3 months after the placement of ventilation tubes in 83 children

  3. RELATIONSHIP BETWEEN HORIZONTAL EXTINCTION COEFFICIENT AND PM10 CONCENTRATION IN XI'AN, CHINA,DURING 1980-2002

    Institute of Scientific and Technical Information of China (English)

    Huizheng Che; Xiaoye Zhang; Yang Li; Zijiang Zhou; Zhenlin Chen

    2006-01-01

    Based on daily visibility data obtained from 1980-2002 and air pollution index data from 2001-2004 in Xi'an, long-term variations and relationships for daily horizontal extinction coefficient and mass concentration of PM10 have been evaluated. A decreasing trend was found in horizontal extinction coefficient during the past 23 years, with higher values observed in 1980s relative to 1990s, and the highest and lowest values in winter and summer, respectively.Significant correlation and similar seasonal variations existed between horizontal extinction coefficient and PM10 concentration, suggesting the high influence of PM10 to the visibility drop at a site in the Guanzhong Plain of central China during the past two decades.

  4. Enteral Tube Feeding and Pneumonia

    Science.gov (United States)

    Gray, David Sheridan; Kimmel, David

    2006-01-01

    To determine the effects of enteral tube feeding on the incidence of pneumonia, we performed a retrospective review of all clients at our institution who had gastrostomy or jejunostomy tubes placed over a 10-year period. Ninety-three subjects had a history of pneumonia before feeding tube insertion. Eighty had gastrostomy and 13, jejunostomy…

  5. Experimental determination of heat transfer and friction in helically-finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zdaniuk, Gregory J. [Ramboll Whitbybird Ltd., 60 Newman Street, London W1T 3DA (United Kingdom); Chamra, Louay M.; Mago, Pedro J. [Department of Mechanical Engineering, Mississippi State University, 210 Carpenter Engineering Building, P.O. Box ME, Mississippi State, MS 39762-5925 (United States)

    2008-01-15

    Heat transfer coefficients and friction factors were determined experimentally for eight helically-finned tubes and one smooth tube using liquid water at Reynolds numbers ranging from 12,000 to 60,000. The helically-finned tubes tested in this investigation have helix angles between 25 and 48 , number of fin starts between 10 and 45, and fin height-to-diameter ratios between 0.0199 and 0.0327. An uncertainty analysis was completed and plain-tube results were compared to the Blasius and Dittus-Boelter equations with satisfactory agreement. Power-law correlations for Fanning friction and Colburn j-factors were developed using a least-squares regression. The performance of the correlations was evaluated with data of other researchers with average prediction errors between 30% and 40%. (author)

  6. Fluctuations of the horizontal wind under unstable conditions

    Science.gov (United States)

    van den Hurk, B. J. J. M.; de Bruin, H. A. R.

    1995-06-01

    The similarity relations for σu/u* proposed by Panofsky et al. (1977) and Højstrup (1982) have been verified using eddy-correlation data collected during the EFEDA-experiment, conducted over the extensive plain of La Mancha (Spain), where vine plants form a primary crop. Also, the standard Monin-Obukhov relation is considered. It is found that the expressions by Panofsky et al. and Højstrup both yield almost identical results, and are better than the Monin-Obukhov expression. Also, σu measured with a cup anemometer obeys the similarity expressions well, provided that the effect of the variation of wind direction on propellor wind speed is accounted for. The relationship of Panofsky et al. works rather well even when the boundary-layer height scale h is replaced by a fixed height, h c. Best results were obtained for h c=1800 m. This height scale is possibly associated with the horizontal variability in the surface sensible heat flux pattern.

  7. Heat transfer enhancement in two-start spirally corrugated tube

    Directory of Open Access Journals (Sweden)

    Zaid S. Kareem

    2015-09-01

    Full Text Available Various techniques have been tested on heat transfer enhancement to upgrade the involving equipment, mainly in thermal transport devices. These techniques unveiled significant effects when utilized in heat exchangers. One of the most essential techniques used is the passive heat transfer technique. Corrugations represent a passive technique. In addition, it provides effective heat transfer enhancement because it combined the features of extended surfaces, turbulators and artificial roughness. Therefore, A Computational Fluid Dynamics was employed for water flowing at low Reynolds number in spiral corrugated tubes. This article aimed for the determination of the thermal performance of unique smooth corrugation profile. The Performance Evaluation Criteria were calculated for corrugated tubes, and the simulation results of both Nusselt number and friction factor were compared with those of standard plain and corrugated tubes for validation purposes. Results showed the best thermal performance range of 1.8–2.3 for the tube which has the severity of 45.455 × 10−3 for Reynolds number range of 100–700. The heat transfer enhancement range was 21.684%–60.5402% with friction factor increase of 19.2–36.4%. This indicated that this creative corrugation can improve the heat transfer significantly with appreciably increasing friction factor.

  8. Optimizing of Culture Conditionin Horizontal Rotating Bioreactor

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionBioreactor is the most important equipment in tissue engineering. It can mimic the micro-environment of cell growth in vitro. At present, horizontal rotating bioreactor is the most advanced equipment for cell culture in the world. 2 Rotating bioreactors2.1 Working principleThere are two kinds of horizontal rotating bioreactor: HARV(high aspect ratio vessel) and RCCS (rotary cell culture system). It is drived by step motor with horizontal rotation, the culture medium and cell is filled between ...

  9. Horizontal gene transfer and bacterial diversity

    Indian Academy of Sciences (India)

    Chitra Dutta; Archana Pan

    2002-02-01

    Bacterial genomes are extremely dynamic and mosaic in nature. A substantial amount of genetic information is inserted into or deleted from such genomes through the process of horizontal transfer. Through the introduction of novel physiological traits from distantly related organisms, horizontal gene transfer often causes drastic changes in the ecological and pathogenic character of bacterial species and thereby promotes microbial diversification and speciation. This review discusses how the recent influx of complete chromosomal sequences of various microorganisms has allowed for a quantitative assessment of the scope, rate and impact of horizontally transmitted information on microbial evolution.

  10. Neural tube defects

    Directory of Open Access Journals (Sweden)

    M.E. Marshall

    1981-09-01

    Full Text Available Neural tube defects refer to any defect in the morphogenesis of the neural tube, the most common types being spina bifida and anencephaly. Spina bifida has been recognised in skeletons found in north-eastern Morocco and estimated to have an age of almost 12 000 years. It was also known to the ancient Greek and Arabian physicians who thought that the bony defect was due to the tumour. The term spina bifida was first used by Professor Nicolai Tulp of Amsterdam in 1652. Many other terms have been used to describe this defect, but spina bifida remains the most useful general term, as it describes the separation of the vertebral elements in the midline.

  11. Vortex tube optimization theory

    Energy Technology Data Exchange (ETDEWEB)

    Lewins, Jeffery [Cambridge Univ., Magdalene Coll., Cambridge (United Kingdom); Bejan, Adrian [Duke Univ., Dept. of Mechanical Engineering and Materials Science, Durham, NC (United States)

    1999-11-01

    The Ranque-Hilsch vortex tube splits a single high pressure stream of gas into cold and warm streams. Simple models for the vortex tube combined with regenerative precooling are given from which an optimisation can be undertaken. Two such optimisations are needed: the first shows that at any given cut or fraction of the cold stream, the best refrigerative load, allowing for the temperature lift, is nearly half the maximum loading that would result in no lift. The second optimisation shows that the optimum cut is an equal division of the vortex streams between hot and cold. Bounds are obtainable within this theory for the performance of the system for a given gas and pressure ratio. (Author)

  12. Effects of Horizontal Resolution on Cumulus Cloud Simulations

    Science.gov (United States)

    Lindsey, L.; Randall, D. A.; Dazlich, D.

    2012-12-01

    The horizontal resolution of cumulus cloud simulations not only affects the computational cost of running a cloud resolving model (CRM), but it affects the results of the model as well. It is necessary to find the coarsest resolution that can be used without compromising the accuracy of the results. This study was carried out using the System for Atmospheric Modeling (SAM), a three-dimensional cloud resolving model. The forcing data used for the model came from two different field campaigns, the GARP Atlantic Tropical Experiment (GATE) and Atmospheric Radiation Measurement Program (ARM) at the Southern Great Plains site. GATE took place during the summer of 1974 over the tropical Atlantic Ocean. The ARM field campaign took place during the summer of 1997. A constant large scale forcing was applied to the temperature and moisture fields for the GATE case. The model was run until the atmospheric water content stabilized. With the ARM forcing data, a diurnal cycle of solar insolation was applied. The model was run until the soil moisture adjusted. For both GATE and ARM, a 20-day period was analyzed. The effects of horizontal grid spacing on rainfall rates, updraft and downdraft velocities, and cloud cover are presented in this study. Grid spacings of 8 km, 4 km, 2 km, and 500 m were studied for the GATE runs, and 4 km, 2 km, 1 km, and 500 m were studied for the ARM runs. For the GATE runs, resolution does not have a great impact on rainfall rates. A more radical effect is seen on updrafts and downdrafts, which intensify with higher resolutions. The overall cloud cover for the GATE runs decrease with increased resolution. The ARM runs are more sensitive to horizontal resolution than the GATE runs. Domain averaged rainfall rates decrease with increased resolution. Local rainfall rates, on the contrary, increase with increased resolution. In the ARM runs updrafts and downdrafts intensify with increased resolution. Cloud cover decreases with increased resolution. Grid

  13. Plain carbon steel bipolar plates for PEMFC

    Institute of Scientific and Technical Information of China (English)

    WANG Jianli; SUN Juncai; TIAN Rujin; XU Jing

    2006-01-01

    Bipolar plates are a multifunctional component of PEMFC. Comparing with the machined graphite and stainless steels, the plain carbon steel is a very cheap commercial metal material. In this paper, the possibility of applying the plain carbon steels in the bipolar plate for PEMFC was exploited. In order to improve the corrosion resistance of the low carbon steel in the PEMFCs' environments,two surface modification processes was developed and then the electrochemical performances and interfacial contact resistance (ICR) of the surface modified plate of plain carbon steel were investigated. The results show that the surface modified steel plates have good corrosion resistance and relatively low contact resistance, and it may be a candidate material as bipolar plate of PEMFC.

  14. A wandering tube.

    Science.gov (United States)

    Dubin, Ina; Gelber, Moshe; Schattner, Ami

    2016-12-05

    The predominant causes of acute mechanical small bowel obstruction in geriatric patients are adhesions and hernias, which is not much different than in other adult age groups. Unusual etiologies may be encountered, such as volvulus or gallstone ileus, but a displaced feeding gastrostomy tube is a distinctly rare cause of intestinal obstruction which needs to be considered by emergency physicians as it may be increasingly encountered.

  15. Primary fallopian tube carcinoma

    Directory of Open Access Journals (Sweden)

    Mladenović-Segedi Ljiljana

    2009-01-01

    Full Text Available Introduction. Primary fallopian tube carcinoma is extremely rare, making 0.3-1.6% of all female genital tract malignancies. Although the etymology of this tumor is unknown, it is suggested to be associated with chronic tubal inflammation, infertility, tuberculous salpingitis and tubal endometriosis. High parity is considered to be protective. Cytogenetic studies show the disease to be associated with over expression of p53, HER2/neu and c-myb. There is also some evidence that BRCA1 and BRCA2 mutations have a role in umorogeneis. Clinical features. The most prevailing symptoms with fallopian tube carcinoma are abdominal pain, abnormal vaginal discharge/bleeding and the most common finding is an adnexal mass. In many patients, fallopian tube carcinoma is asymptomatic. Diagnosis. Due to its rarity, preoperative diagnosis of primary fallopian tube carcinoma is rarely made. It is usually misdiagnosed as ovarian carcinoma, tuboovarian abscess or ectopic pregnancy. Sonographic features of the tumor are non-specific and include the presence of a fluid-filled adnexal structure with a significant solid component, a sausage-shaped mass, a cystic mass with papillary projections within, a cystic mass with cog wheel appearance and an ovoid-shaped structure containing an incomplete separation and a highly vascular solid nodule. More than 80% of patients have elevated pretreatment serum CA-125 levels, which is useful in follow-up after the definite treatment. Treatment. The treatment approach is similar to that of ovarian carcinoma, and includes total abdominal hysterectomy and bilateral salpingo-oophorectomy. Staging is followed with chemotherapy.

  16. Two-phase flow patterns for flow condensation in small-diameter tubes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Two-phase flow patterns have been observed visually to investigate the effects of tube diameter, mass flux and tube inclination on flow condensation in small-diameter tubes. For horizontal or inclined small-diameter tubes, gravity-domination is decreased by shear stress and surface tension on phase change interface, which weakens the stratification of condensate and vapor flow due to the action of gravity perpendicular to flow direction. As decreasing the tube diameter from 5.79 mm to 2.18 mm, the annular or sub-annular flows become prevailing in flow regime map. The existing flow regime maps for macro scale cannot predict the experimental data in the present study.

  17. Tube array heat transfer in fluidized beds; a study of particle size effects

    Energy Technology Data Exchange (ETDEWEB)

    Chung, T.Y.; Welty, J.R. (Oregon State Univ., Corvallis, OR (USA). Dept. of Mechanical Engineering)

    1989-07-01

    Experiments were performed with an array of horizontal tubes, arranged in a regular equilateral triangular pattern, immersed in a fluidized bed operating at 812 {Kappa}. Data are reported for heat transfer between the bed and a centrally-located tube in the array. Both total and radiative heat transfer rates were measured for superficial velocities spanning the range from packed bed conditions to over twice the minimum fluidization velocity. Results are presented for five different-size particles. Local heat transfer values, measured around the tube periphery, and integrated averages are reported for all test conditions. Comparisons are also made between the heat transfer behavior of a tube in an array and that for a single tube in a hot fluidized bed under the same overall operating conditions. The results of this comparison suggests that the two mechanisms, gas convection and radiation, are competing effects.

  18. Traveling-Wave Tubes

    Science.gov (United States)

    Kory, Carol L.

    1998-01-01

    The traveling-wave tube (TWT) is a vacuum device invented in the early 1940's used for amplification at microwave frequencies. Amplification is attained by surrendering kinetic energy from an electron beam to a radio frequency (RF) electromagnetic wave. The demand for vacuum devices has been decreased largely by the advent of solid-state devices. However, although solid state devices have replaced vacuum devices in many areas, there are still many applications such as radar, electronic countermeasures and satellite communications, that require operating characteristics such as high power (Watts to Megawatts), high frequency (below 1 GHz to over 100 GHz) and large bandwidth that only vacuum devices can provide. Vacuum devices are also deemed irreplaceable in the music industry where musicians treasure their tube-based amplifiers claiming that the solid-state and digital counterparts could never provide the same "warmth" (3). The term traveling-wave tube includes both fast-wave and slow-wave devices. This article will concentrate on slow-wave devices as the vast majority of TWTs in operation fall into this category.

  19. Hydrogeochemical analysis for Tasuj plain aquifer, Iran

    Indian Academy of Sciences (India)

    Ata Allah Nadiri; Asghar Asghari Moghaddam; Frank T-C Tsai; Elham Fijani

    2013-08-01

    This study investigated the hydrogeochemical processes of groundwater in the Tasuj plain, Iran. The Tasuj plain is one of the 12 marginal plains around Urmia Lake which is currently under a critical ecological condition. In the last decades, the Tasuj plain aquifer suffered from severe groundwater level declination and caused degradation of groundwater quality. To better understand hydrogeochemical processes in the Tasuj plain, this study adopted graphical methods and multivariate statistical techniques to analyze groundwater samples. A total of 504 groundwater samples was obtained from 34 different locations (qanats, wells, and springs) over 12 years (1997–2009) and analyzed for 15 water quality parameters. From the results, the Piper diagram indicated four groundwater types and the Stiff diagram showed eight different sources of groundwater samples. The Durov diagram identified five major hydrogeochemical processes in the aquifer. However, hierarchical cluster analysis (HCA) identified five water types in the groundwater samples because HCA was able to analyze more chemical and physical data than graphical methods. The HCA result was checked by discriminant analysis and found consistency in all samples that were classified into correct groups. Using factor analysis, we identified three factors that accounted for 81.6% of the total variance of the dataset. Based on the high factor loadings of the variables, factors 1 and 2 reflected the natural hydrogeochemical processes and factor 3 explained the effect of agricultural fertilizers and human activities in the Tasuj plain. Dendrograms from 2000 to 2009 were studied to understand the temporal variation of groundwater quality. Comparing the distributions of groundwater types in 2000 and 2009, we found that the mixing zone was expanded. This may be due to artificial groundwater recharge in the recharge area and the effect of inverse ion exchange in the discharge area.

  20. Pressure Loss across Tube Bundles in Two-phase Flow

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Woo Gun; Banzragch, Dagdan [Hannam Univ., Daejon (Korea, Republic of)

    2016-03-15

    An analytical model was developed by Sim to estimate the two-phase damping ratio for upward two-phase flow perpendicular to horizontal tube bundles. The parameters of two-phase flow, such as void fraction and pressure loss evaluated in the model, were calculated based on existing experimental formulations. However, it is necessary to implement a few improvements in the formulations for the case of tube bundles. For the purpose of the improved formulation, we need more information about the two-phase parameters, which can be found through experimental test. An experiment is performed with a typical normal square array of cylinders subjected to the two-phase flow of air-water in the tube bundles, to calculate the two-phase Euler number and the two-phase friction multiplier. The pitch-to-diameter ratio is 1.35 and the diameter of cylinder is 18mm. Pressure loss along the flow direction in the tube bundles is measured with a pressure transducer and data acquisition system to calculate the two-phase Euler number and the two-phase friction multiplier. The void fraction model by Feenstra et al. is used to estimate the void fraction of the two-phase flow in tube bundles. The experimental results of the two phase friction multiplier and two-phase Euler number for homogeneous and non-homogeneous two-phase flows are compared and evaluated against the analytical results given by Sim's model.

  1. Drought Assessment in the Moldavian Plain

    Directory of Open Access Journals (Sweden)

    Pelin Liviu Ioan

    2016-06-01

    Full Text Available The Moldavian Plain, located in the North-Eastern part of Romania, has a temperate-continental climate with a nuance of excessivity in the precipitation regime. This paper aims to analyse droughts in the Moldavian Plain for the period 1961-2010, by using a classical method - the de Martonne Aridity Index, and two other less known indices developed in Romania and the Republic of Moldova. Among these indices, the Dry Spells Index demonstrates a increasing frequency of dry years in recent decades.

  2. Reliability of steam generator tubing

    Energy Technology Data Exchange (ETDEWEB)

    Kadokami, E. [Mitsubishi Heavy Industries Ltd., Hyogo-ku (Japan)

    1997-02-01

    The author presents results on studies made of the reliability of steam generator (SG) tubing. The basis for this work is that in Japan the issue of defects in SG tubing is addressed by the approach that any detected defect should be repaired, either by plugging the tube or sleeving it. However, this leaves open the issue that there is a detection limit in practice, and what is the effect of nondetectable cracks on the performance of tubing. These studies were commissioned to look at the safety issues involved in degraded SG tubing. The program has looked at a number of different issues. First was an assessment of the penetration and opening behavior of tube flaws due to internal pressure in the tubing. They have studied: penetration behavior of the tube flaws; primary water leakage from through-wall flaws; opening behavior of through-wall flaws. In addition they have looked at the question of the reliability of tubing with flaws during normal plant operation. Also there have been studies done on the consequences of tube rupture accidents on the integrity of neighboring tubes.

  3. Hybrid endotracheal tubes

    Science.gov (United States)

    Sakezles, Christopher Thomas

    Intubation involves the placement of a tube into the tracheal lumen and is prescribed in any setting in which the airway must be stabilized or the patient anesthetized. The purpose of the endotracheal tube in these procedures is to maintain a viable airway, facilitate mechanical ventilation, allow the administration of anesthetics, and prevent the reflux of vomitus into the lungs. In order to satisfy these requirements a nearly airtight seal must be maintained between the tube and the tracheal lining. Most conventional endotracheal tubes provide this seal by employing a cuff that is inflated once the tube is in place. However, the design of this cuff and properties of the material are a source of irritation and injury to the tracheal tissues. In fact, the complication rate for endotracheal intubation is reported to be between 10 and 60%, with manifestations ranging from severe sore throat to erosion through the tracheal wall. These complications are caused by a combination of the materials employed and the forces exerted by the cuff on the tracheal tissues. In particular, the abrasive action of the cuff shears cells from the lining, epithelium adhering to the cuff is removed during extubation, and normal forces exerted on the basement tissues disrupt the blood supply and cause pressure necrosis. The complications associated with tracheal intubation may be reduced or eliminated by employing airway devices constructed from hydrogel materials. Hydrogels are a class of crosslinked polymers which swell in the presence of moisture, and may contain more than 95% water by weight. For the current study, several prototype airway devices were constructed from hydrogel materials including poly(vinyl alcohol), poly(hydroxyethyl methacrylate), and poly(vinyl pyrrolidone). The raw hydrogel materials from this group were subjected to tensile, swelling, and biocompatibility testing, while the finished devices were subjected to extensive mechanical simulation and animal trials

  4. Horizontal cooperation in transport and logistics

    NARCIS (Netherlands)

    Cruijssen, F.C.A.M.

    2006-01-01

    This thesis deals with horizontal cooperation in transport and logistics. It contains a comprehensive discussion of the available academic literature on this topic, many practical examples, and an empirical investigation of opportunities and impediments. Furthermore, three enabling concepts for

  5. Mechanical and mathematical models of multi-stage horizontal fracturing strings and their application

    Directory of Open Access Journals (Sweden)

    Zhanghua Lian

    2015-03-01

    Full Text Available Multi-stage SRV fracturing in horizontal wells is a new technology developed at home and abroad in recent years to effectively develop shale gas or low-permeability reservoirs, but on the other hand makes the mechanical environment of fracturing strings more complicated at the same time. In view of this, based on the loading features of tubing strings during the multi-stage fracturing of a horizontal well, mechanical models were established for three working cases of multiple packer setting, open differential-pressure sliding sleeve, and open ball-injection sliding sleeve under a hold-down packer. Moreover, mathematical models were respectively built for the above three cases. According to the Lame formula and Von Mises stress calculation formula for the thick-walled cylinder in the theory of elastic mechanics, a mathematical model was also established to calculate the equivalent stress for tubing string safety evaluation when the fracturing string was under the combined action of inner pressure, external squeezing force and axial stress, and another mathematical model was built for the mechanical strength and safety evaluation of multi-stage fracturing strings. In addition, a practical software was developed for the mechanical safety evaluation of horizontal well multi-stage fracturing strings according to the mathematical model developed for the mechanical calculation of the multi-packer string in horizontal wells. The research results were applied and verified in a gas well of Tahe Oilfield in the Tarim Basin with excellent effects, providing a theoretical basis and a simple and reliable technical means for optimal design and safety evaluation of safe operational parameters of multi-stage fracturing strings in horizontal wells.

  6. Thermalhydraulics of advanced 37-element fuel bundle in crept pressure tubes

    Directory of Open Access Journals (Sweden)

    Park Joo Hwan

    2016-01-01

    Full Text Available A CANDU-6 reactor, which has 380 fuel channels of a pressure tube type, is suffering from aging or creep of the pressure tubes. Most of the aging effects for the CANDU primary heat transport system were originated from the horizontal crept pressure tubes. As the operating years of a CANDU reactor proceed, a pressure tube experiences high neutron irradiation damage under high temperature and pressure. The crept pressure tube can deteriorate the Critical Heat Flux (CHF of a fuel channel and finally worsen the reactor operating performance and thermal margin. Recently, the modification of the central subchannel area with increasing inner pitch length of a standard 37-element fuel bundle was proposed and studied in terms of the dryout power enhancement for the uncrept pressure tube since a standard 37-element fuel bundle has a relatively small flow area and high flow resistance at the central region. This study introduced a subchannel analysis for the crept pressure tubes loaded with the inner pitch length modification of a standard 37-element fuel bundle. In addition, the subchannel characteristics were investigated according to the flow area change of the center subchannels for the crept pressure tubes. Also, it was discussed how much the crept pressure tubes affected the thermalhydraulic characteristics of the fuel channel as well as the dryout power for the modification of a standard 37-element fuel bundle.

  7. Evaluation of extremely small horizontal emittance

    Directory of Open Access Journals (Sweden)

    T. Okugi

    1999-02-01

    Full Text Available The KEK Accelerator Test Facility (KEK-ATF was constructed to develop technologies for producing a low-emittance beam which will be required by future linear colliders. The KEK-ATF consists of an injector linac, a damping ring, and a beam extraction line. The basic optical structure of the damping ring is a FOBO lattice, which reduces the horizontal dispersion at the center of the bending magnets and, as a consequence, can produce an extremely small emittance beam. To verify the performance of such a unique, low-emittance lattice, it is crucial to measure the horizontal emittance. The horizontal emittance was measured using wire scanners in the beam extraction line. Since the horizontal beam position was not stable, we established a method to correct the measured beam size for position fluctuation (“jitter” and we succeeded in the observation of the so far smallest horizontal emittance in any accelerator. The measured horizontal emittance was 1.37±0.03nm at a beam energy of 1.285 GeV and a bunch population of \\(3–5\\×10^{9}, in agreement with the design value of 1.27–1.34 nm at the beam energy and the bunch population.

  8. Water-level change, High Plains aquifer, 1980 to 1995

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 1980 to 1995, in feet. The High Plains aquifer underlies...

  9. Water-level change, High Plains aquifer, 1995 to 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 1995 to 2000, in feet. The High Plains aquifer underlies...

  10. Water-level change, High Plains aquifer, 2005 to 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 2005 to 2009, in feet. The High Plains aquifer underlies...

  11. Water-level change, High Plains aquifer, 2000 to 2005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 2000 to 2005, in feet. The High Plains aquifer underlies...

  12. The Effect of Fin Pitch on Fluid Elastic Instability of Tube Arrays Subjected to Cross Flow of Water

    Science.gov (United States)

    Desai, Sandeep Rangrao; Pavitran, Sampat

    2016-07-01

    Failure of tubes in shell and tube exchangers is attributed to flow induced vibrations of such tubes. There are different excitations mechanisms due to which flow induced vibration occurs and among such mechanisms, fluid elastic instability is the most prominent one as it causes the most violent vibrations and may lead to rapid tube failures within short time. Fluid elastic instability is the fluid-structure interaction phenomenon which occurs when energy input by the fluid force exceeds energy expended in damping. This point is referred as instability threshold and corresponding velocity is referred as critical velocity. Once flow velocity exceeds critical flow velocity, the vibration amplitude increases very rapidly with flow velocity. An experimental program is carried out to determine the critical velocity at instability for plain and finned tube arrays subjected to cross flow of water. The tube array geometry is parallel triangular with cantilever end condition and pitch ratios considered are 2.6 and 2.1. The objective of research is to determine the effect of increase in pitch ratio on instability threshold for plain tube arrays and to assess the effect of addition of fins as well as increase in fin density on instability threshold for finned tube arrays. Plain tube array with two different pitch ratios; 2.1 and 2.6 and finned tube arrays with same pitch ratio; 2.6 but with two different fin pitches; such as fine (10 fpi) and coarse (4 fpi) are considered for the experimentation. Connors' equation that relates critical velocity at instability to different parameters, on which instability depends, has been used as the basis for analysis and the concept of effective diameter is used for the present investigation. The modal parameters are first suitably modified using natural frequency reduction setup that is already designed and developed to reduce natural frequency and hence to achieve experimental simulation of fluid elastic instability within the limited

  13. Necrotizing fasciitis : plain radiographic and CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Dae; Park, Jeong Hee; Jeon, Hae Jeong; Lim, Jong Nam; Heo, Tae Haeng; Park, Dong Rib [Konkuk Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-11-01

    To evaluate the plain radiographic and CT findings of the necrotizing fasciitis. We retrospectively reviewed the radiologic findings of 4 cases with necrotizing fasciitis. Three cases were proven pathologically. We evaluated pattern and extent of the gas shadows in plain films. CT findings were analysed, with emphasis on : (a) gas pattern, (b) extent, (c) location and involved site, (d) associated focal abscess, and (e) swelling of the adjacent muscles. On plain radiographs, four cases showed streaky or mottled gas densities in the pelvis, three cases in the perineum, one case in the abdomen, and two cases in the thigh. On CT images, gas pattern was mottled and streaky appearance with swelling of the adjacent muscles. Gas shadows located in the extraperitoneal space in four cases, fascial layer in four cases, and subcutaneous layer in four cases. There were gas shadows in pelvic wall, perineum, abdominal wall, buttock, thigh, and scrotum. Focal low density lesion suggestive of focal abscess was not visualized. Plain radiography is useful for early diagnosis of the necrotizing fasciitis and CT is very useful for detection of precise location and extent of the disease. CT is also useful for differentiation of necrotizing fasciitis from focal abscess and cellulitis.

  14. Porosity Prediction of Plain Weft Knitted Fabrics

    Directory of Open Access Journals (Sweden)

    Muhammad Owais Raza Siddiqui

    2014-12-01

    Full Text Available Wearing comfort of clothing is dependent on air permeability, moisture absorbency and wicking properties of fabric, which are related to the porosity of fabric. In this work, a plug-in is developed using Python script and incorporated in Abaqus/CAE for the prediction of porosity of plain weft knitted fabrics. The Plug-in is able to automatically generate 3D solid and multifilament weft knitted fabric models and accurately determine the porosity of fabrics in two steps. In this work, plain weft knitted fabrics made of monofilament, multifilament and spun yarn made of staple fibers were used to evaluate the effectiveness of the developed plug-in. In the case of staple fiber yarn, intra yarn porosity was considered in the calculation of porosity. The first step is to develop a 3D geometrical model of plain weft knitted fabric and the second step is to calculate the porosity of the fabric by using the geometrical parameter of 3D weft knitted fabric model generated in step one. The predicted porosity of plain weft knitted fabric is extracted in the second step and is displayed in the message area. The predicted results obtained from the plug-in have been compared with the experimental results obtained from previously developed models; they agreed well.

  15. The geologic story of the Great Plains

    Science.gov (United States)

    Trimble, Donald E.

    1980-01-01

    The Great Plains! The words alone create a sense of space and a feeling of destiny a challenge. But what exactly is this special part of Western America that contains so much of our history? How did it come to be? Why is it different?

  16. Pedogeographic regionalization of the Pomurje plain

    Directory of Open Access Journals (Sweden)

    Franc Lovrenčak

    1991-12-01

    Full Text Available The paper deals with the pedogeographic regionalization of the Pomurje plain (Northeast Slovenia. With regard to differences in parent material, landforms, and hydrographic characteristics, the soil cover is ranked into two pedogeographic regions. Each of them is furthermore divided into several subregions grouped together according to related soil groups.

  17. Great plains regional climate assessment technical report

    Science.gov (United States)

    The Great Plains region (GP) plays important role in providing food and energy to the economy of the United States. Multiple climatic and non-climatic stressors put multiple sectors, livelihoods and communities at risk, including agriculture, water, ecosystems and rural and tribal communities. The G...

  18. Further Studies in Filmwise Condensation of Steam on Horizontal Finned Tubes

    Science.gov (United States)

    1992-03-01

    1/3 (JL4 )0 14= 1.4 (held constant for comparison) ........... 63 Table 5. COMPARISON OF REYNOLDS NUMBER EXPONENTS FOR SIEDER -TATE-TYPE CORRELATIONS...A. effective outside surface area (m) Ci Sieder - Tate leading coefficient Cf mass flow rate correction factor cp specific heat at constant pressure...heat-transfer correlations used during the data reduction process. Previously, the standard Sieder -Tate correlation was assumed to be valid for the

  19. Filmwise Condensation of Steam on Horizontal Wire-Wrapped Smooth and Roped Titanium Tubes

    Science.gov (United States)

    1992-09-01

    10.01- 12 7.77 3.E~ .7+4 E7~-0- ’.~10 14 4.9 .. 0704E+0 4 9 Least-Square5 Line 0or Ho v5 q curva : Siope - Intercept = ".040E-OS Least-5que~res line for...Paul J. Marto, Code ME/Mx 4 Department of Mechanical Engineering Naval Postgraduate School Monterey, CA 93943-5004 6. Professor Stephan B. Memory

  20. A self propelled drilling system for hard-rock, horizontal and coiled tube drilling

    Energy Technology Data Exchange (ETDEWEB)

    Biglin, D.; Wassell, M.

    1997-12-31

    Several advancements are needed to improve the efficiency and reliability of both hard rock drilling and extended reach drilling. This paper will present a Self Propelled Drilling System (SPDS) which can grip the borehole wall in order to provide a stable platform for the application of weight on bit (WOB) and resisting the reactive torque created by the downhole drilling motor, bit and formation interaction. The system will also dampen the damaging effects of drill string vibration. This tool employs two hydraulically activated anchors (front and rear) to grip the borehole wall, and a two-way thrust mandrel to apply both the drilling force to the bit, and a retraction force to pull the drill string into the hole. Forward drilling motion will commence by sequencing the anchor pistons and thrust mandrel to allow the tool to walk in a stepping motion. The SPDS has a microprocessor to control valve timing, sensing and communication functions. An optional Measurement While Drilling (MWD) interface can provide two-way communication of critical operating parameters such as hydraulic pressure and piston location. This information can then be telemetered to the surface, or used downhole to autonomously control system parameters such as anchor and thrust force or damping characteristics.

  1. Lava Tube Collapse Pits

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form. These collapse pits are found in the southern hemisphere of Mars. They are likely lava tube collapse pits related to flows from Hadriaca Patera. Image information: VIS instrument. Latitude -36.8, Longitude 89.6 East (270.4 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D

  2. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and...

  3. Preliminary geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California

    Science.gov (United States)

    Minor, Scott A.; Kellogg, Karl S.; Stanley, Richard G.; Stone, Paul; Powell, Charles L.; Gurrola, Larry D.; Selting, Amy J.; Brandt, Theodore R.

    2002-01-01

    This report presents a new geologic digital map of the Santa Barbara coastal plain area at a compilation scale of 1:24,000 (one inch on the map = 2,000 feet on the ground) and with a horizontal positional accuracy of at least 20 m. This preliminary map depicts the distribution of bedrock units and surficial deposits and associated deformation underlying and adjacent to the coastal plain within the contiguous Santa Barbara and Goleta 7.5' quadrangles. A planned second version will extend the mapping westward into the adjoining Dos Pueblos Canyon quadrangle and eastward into the Carpinteria quadrangle. The mapping presented here results from the collaborative efforts of geologists with the U.S. Geological Survey Southern California Areal Mapping Project (SCAMP) (Minor, Kellogg, Stanley, Stone, and Powell) and the tectonic geomorphology research group at the University of California at Santa Barbara (Gurrola and Selting). C.L. Powell, II, performed all new fossil identifications and interpretations reported herein. T.R. Brandt designed and edited the GIS database,performed GIS database integration and created the digital cartography for the map layout. The Santa Barbara coastal plain is located in the western Transverse Ranges physiographic province along a west-trending segment of the southern California coastline about 100 km (62 mi) northwest of Los Angeles. The coastal plain region, which extends from the Santa Ynez Mountains on the north to the Santa Barbara Channel on the south, is underlain by numerous active and potentially active folds and partly buried thrust faults of the Santa Barbara fold and fault belt. Strong earthquakes that occurred in the region in 1925 (6.8 magnitude) and 1978 (5.1 magnitude) are evidence that such structures pose a significant earthquake hazard to the approximately 200,000 people living within the major coastal population centers of Santa Barbara and Goleta. Also, young landslide deposits along the steep lower flank of the Santa

  4. Horizontal roof gap of backfill hydraulic support

    Institute of Scientific and Technical Information of China (English)

    张强; 张吉雄; 邰阳; 方坤; 殷伟

    2015-01-01

    For the backfill hydraulic support as the key equipment for achieving integration of backfilling and coal mining simultaneously in the practical process, its characteristics will directly influence the backfill body’s compression ratio. Horizontal roof gap, as a key parameter of backfilling characteristics, may impact the backfilling effect from the aspects of control of roof subsidence in advance, support stress, backfilling process and the support design. Firstly, the reason why horizontal roof gap exists was analyzed and its definition, causes and connotation were introduced, then adopting the Pro/E 3D simulation software, three typical 3D entity models of backfill hydraulic supports were built, based on the influence of horizontal roof gap on backfilling effect, and influence rules of four factors, i.e. support height, suspension height, suspension angle and tamping angle, were emphatically analyzed on horizontal roof gap. The results indicate that, the four factors all have significant impacts on horizontal roof gap, but show differences in influence trend and degree, showing negative linear correlation, positive linear correlation, positive semi-parabolic correlation and negative semi-parabolic correlation, respectively. Four legs type is the most adaptive to the four factors, while six legs (II) type has the poorest adaptability, and the horizontal roof gap is small under large support height, small suspension height, small suspension angle and large tamping angle situation. By means of optimizing structure components and their positional relation and suspension height of backfill scrape conveyor in the process of support design and through controlling working face deployment, roof subsidence in advance, mining height and backfilling during engineering application, the horizontal roof gap is optimized. The research results can be served as theoretical basis for support design and guidance for backfill support to have better performance in backfilling.

  5. Tube coalescence in the Jingfudong lava tube and implications for lava flow hazard of Tengchong volcanism

    OpenAIRE

    Zhengquan Chen; Yongshun Liu; Haiquan Wei; Jiandong Xu; Wenfeng Guo

    2016-01-01

    Tube-fed structure occurs as a general phenomenon in Tengchong basic lavas, such as lava tubes, lava plugs and tube-related collapse depressions. We deduced the development of Laoguipo lava flows, which is the longest lava tube (Jingfudong lava tube) evolved in Tengchong volcanic area. Following the detailed documentation of the tube morphology of the Jingfudong lava tube, we propose that the Jingfudong lava tube was formed through vertical coalescence of at least three tubes. The coalescence...

  6. Steam generator tube integrity program

    Energy Technology Data Exchange (ETDEWEB)

    Dierks, D.R.; Shack, W.J. [Argonne National Laboratory, IL (United States); Muscara, J.

    1996-03-01

    A new research program on steam generator tubing degradation is being sponsored by the U.S. Nuclear Regulatory Commission (NRC) at Argonne National Laboratory. This program is intended to support a performance-based steam generator tube integrity rule. Critical areas addressed by the program include evaluation of the processes used for the in-service inspection of steam generator tubes and recommendations for improving the reliability and accuracy of inspections; validation and improvement of correlations for evaluating integrity and leakage of degraded steam generator tubes, and validation and improvement of correlations and models for predicting degradation in steam generator tubes as aging occurs. The studies will focus on mill-annealed Alloy 600 tubing, however, tests will also be performed on replacement materials such as thermally-treated Alloy 600 or 690. An overview of the technical work planned for the program is given.

  7. Effluent Salinity of Pipe Drains and Tube-Wells. A case study from the Indus plain

    NARCIS (Netherlands)

    Kelleners, T.J.

    2001-01-01

    Keywords: anisotropy, aquifer, desalinization, effluent salinity, groundwater, irrigation, salt-water upconing, soil salinity, stream-function, subsurface drainageIrrigated agriculture in arid and semi-arid zones often suffers from waterlogging and salinity problems. Sub-surface drainage systems can

  8. Horizontal alveolar bone loss: A periodontal orphan

    Directory of Open Access Journals (Sweden)

    Jayakumar A

    2010-01-01

    Full Text Available Background: Attempts to successfully regenerate lost alveolar bone have always been a clinician′s dream. Angular defects, at least, have a fairer chance, but the same cannot be said about horizontal bone loss. The purpose of the present study was to evaluate the prevalence of horizontal alveolar bone loss and vertical bone defects in periodontal patients; and later, to correlate it with the treatment modalities available in the literature for horizontal and vertical bone defects. Materials and Methods: The study was conducted in two parts. Part I was the radiographic evaluation of 150 orthopantomographs (OPGs (of patients diagnosed with chronic periodontitis and seeking periodontal care, which were digitized and read using the AutoCAD 2006 software. All the periodontitis-affected teeth were categorized as teeth with vertical defects (if the defect angle was ≤45° and defect depth was ≥3 mm or as having horizontal bone loss. Part II of the study comprised search of the literature on treatment modalities for horizontal and vertical bone loss in four selected periodontal journals. Results: Out of the 150 OPGs studied, 54 (36% OPGs showed one or more vertical defects. Totally, 3,371 teeth were studied, out of which horizontal bone loss was found in 3,107 (92.2% teeth, and vertical defects were found only in 264 (7.8% of the teeth, which was statistically significant (P<.001. Search of the selected journals revealed 477 papers have addressed the treatment modalities for vertical and horizontal types of bone loss specifically. Out of the 477 papers, 461 (96.3% have addressed vertical bone loss, and 18 (3.7% have addressed treatment options for horizontal bone loss. Two papers have addressed both types of bone loss and are included in both categories. Conclusion: Horizontal bone loss is more prevalent than vertical bone loss but has been sidelined by researchers as very few papers have been published on the subject of regenerative treatment

  9. Diffusion in a Curved Tube

    OpenAIRE

    Ogawa, Naohisa

    2011-01-01

    The diffusion of particles in confining walls forming a tube is discussed. Such a transport phenomenon is observed in biological cells and porous media. We consider the case in which the tube is winding with curvature and torsion, and the thickness of the tube is sufficiently small compared with its curvature radius. We discuss how geomerical quantities appear in a quasi-one-dimensional diffusion equation.

  10. The special relativistic shock tube

    Science.gov (United States)

    Thompson, Kevin W.

    1986-01-01

    The shock-tube problem has served as a popular test for numerical hydrodynamics codes. The development of relativistic hydrodynamics codes has created a need for a similar test problem in relativistic hydrodynamics. The analytical solution to the special relativistic shock-tube problem is presented here. The relativistic shock-jump conditions and rarefaction solution which make up the shock tube are derived. The Newtonian limit of the calculations is given throughout.

  11. Tubing for augmented heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Yampolsky, J.S.; Pavlics, P.

    1983-08-01

    The objectives of the program reported were: to determine the heat transfer and friction characteristics on the outside of spiral fluted tubing in single phase flow of water, and to assess the relative cost of a heat exchanger constructed with spiral fluted tubing with one using conventional smooth tubing. An application is examined where an isolation water/water heat exchanger was used to transfer the heat from a gaseous diffusion plant to an external system for energy recovery. (LEW)

  12. Alternate tube plugging criteria for steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Cueto-Felgueroso, C.; Aparicio, C.B. [Tecnatom, S.A., Madrid (Spain)

    1997-02-01

    The tubing of the Steam Generators constitutes more than half of the reactor coolant pressure boundary. Specific requirements governing the maintenance of steam generator tubes integrity are set in Plant Technical Specifications and in Section XI of the ASME Boiler and Pressure Vessel Code. The operating experience of Steam Generator tubes of PWR plants has shown the existence of some types of degradatory processes. Every one of these has an specific cause and affects one or more zones of the tubes. In the case of Spanish Power Plants, and depending on the particular Plant considered, they should be mentioned the Primary Water Stress Corrosion Cracking (PWSCC) at the roll transition zone (RTZ), the Outside Diameter Stress Corrosion Cracking (ODSCC) at the Tube Support Plate (TSP) intersections and the fretting with the Anti-Vibration Bars (AVBs) or with the Support Plates in the preheater zone. The In-Service Inspections by Eddy Currents constitutes the standard method for assuring the SG tubes integrity and they permit the monitoring of the defects during the service life of the plant. When the degradation reaches a determined limit, called the plugging limit, the SG tube must be either repaired or retired from service by plugging. Customarily, the plugging limit is related to the depth of the defect. Such depth is typically 40% of the wall thickness of the tube and is applicable to any type of defect in the tube. In its origin, that limit was established for tubes thinned by wastage, which was the predominant degradation in the seventies. The application of this criterion for axial crack-like defects, as, for instance, those due to PWSCC in the roll transition zone, has lead to an excessive and unnecessary number of tubes being plugged. This has lead to the development of defect specific plugging criteria. Examples of the application of such criteria are discussed in the article.

  13. Learning from YouTube [Video Book

    Science.gov (United States)

    Juhasz, Alexandra

    2011-01-01

    YouTube is a mess. YouTube is for amateurs. YouTube dissolves the real. YouTube is host to inconceivable combos. YouTube is best for corporate-made community. YouTube is badly baked. These are a few of the things Media Studies professor Alexandra Juhasz (and her class) learned about YouTube when she set out to investigate what actually happens…

  14. Method for producing a tube

    Science.gov (United States)

    Peterson, Kenneth A.; Rohde, Steven B.; Pfeifer, Kent B.; Turner, Timothy S.

    2007-01-02

    A method is described for producing tubular substrates having parallel spaced concentric rings of electrical conductors that can be used as the drift tube of an Ion Mobility Spectrometer (IMS). The invention comprises providing electrodes on the inside of a tube that are electrically connected to the outside of the tube through conductors that extend between adjacent plies of substrate that are combined to form the tube. Tubular substrates are formed from flexible polymeric printed wiring board materials, ceramic materials and material compositions of glass and ceramic, commonly known as Low Temperature Co-Fired Ceramic (LTCC). The adjacent plies are sealed together around the electrode.

  15. YouTube and 'psychiatry'.

    Science.gov (United States)

    Gordon, Robert; Miller, John; Collins, Noel

    2015-12-01

    YouTube is a video-sharing website that is increasingly used to share and disseminate health-related information, particularly among younger people. There are reports that social media sites, such as YouTube, are being used to communicate an anti-psychiatry message but this has never been confirmed in any published analysis of YouTube clip content. This descriptive study revealed that the representation of 'psychiatry' during summer 2012 was predominantly negative. A subsequent smaller re-analysis suggests that the negative portrayal of 'psychiatry' on YouTube is a stable phenomenon. The significance of this and how it could be addressed are discussed.

  16. Charm production in flux tubes

    CERN Document Server

    Aguiar, C E; Nazareth, R A M S; Pech, G

    1996-01-01

    We argue that the non-perturbative Schwinger mechanism may play an important role in the hadronic production of charm. We present a flux tube model which assumes that the colliding hadrons become color charged because of gluon exchange, and that a single non-elementary flux tube is built up as they recede. The strong chromoelectric field inside this tube creates quark pairs (including charmed ones) and the ensuing color screening breaks the tube into excited hadronic clusters. On their turn these clusters, or `fireballs', decay statistically into the final hadrons. The model is able to account for the soft production of charmed, strange and lighter hadrons within a unified framework.

  17. Charm production in flux tubes

    Science.gov (United States)

    Aguiar, C. E.; Kodama, T.; Nazareth, R. A. M. S.; Pech, G.

    1996-01-01

    We argue that the nonperturbative Schwinger mechanism may play an important role in the hadronic production of charm. We present a flux tube model which assumes that the colliding hadrons become color charged because of gluon exchange, and that a single nonelementary flux tube is built up as they recede. The strong chromoelectric field inside this tube creates quark pairs (including charmed ones) and the ensuing color screening breaks the tube into excited hadronic clusters. In their turn these clusters, or ``fireballs,'' decay statistically into the final hadrons. The model is able to account for the soft production of charmed, strange, and lighter hadrons within a unified framework.

  18. Geomorphological development of Eastern Mongolian plain, Mongolia

    Science.gov (United States)

    khukhuudei, Ulambadrakh; otgonbayar, Orolzodmaa

    2016-04-01

    Several summaries and investigations of the geomorphological description and feature for Eastern Mongolian plain (EMP), the one of the largest geomorphological district, fully covering east side of Mongolia (Murzayev, 1949; Vlodavets, 1950, 1955; Marinov, Khasin, 1954; Marinov, 1966; Nikolayeva, 1971; Selivanov, 1972; Chichagov, 1974, 1976; Grigorov, 1975; Korjuyev, 1982; Syirnev, 1982, 1984) had been publishing continuously. But literature for geomorphology of EMP have been not appeared during over the past 20 years. However, we re-combine the geomorphological development of EMP, according to the results of many publications for surrounding regions of Russia and China and unpublished maps. Main morphology of EMP has the plain, containing with aeolian, fluvial and lacustrine landforms. Plain morphology defined that denudation plains to North Kherlen, South Kherlen, Baruun Urt, Uulbayan, Delgerekh and other which developed on the Paleozoic rocks, layered plain to Choibalsan, Tamsag, Ongon, Gert, Sumiin nuur and Torey- on the Late Cretaceous and Neogene sediments and accumulation plain with alluvial and lacustrine origin such as Menen, Buir nuur, Tamsagbulag, Khalzan and other. These plains of EMP related with tectonics and structure of region and inherited the development of the Mesozoic, particularly Late Mesozoic structure. Large basins of EMP are Tamsag, Choibalsan and Torey and other small basins - from 7-10 km to 25-30 km width and rather a several 10 km extend, cutting a basement. The origin of plain morphology for EMP is interpreted as two main stages of the geomorphological development model, based on geology. In first stage or Late Jurassic (?) - Lower Cretaceous period, there was developed rift basin, then, in second stage or since Late Cretaceous period, plain morphology originated from the intermountain basin that dominated by exogenic process and kept in current EMP area. Data relevant to the development history of EMP are following. 1. Rift volcanism

  19. Summary of the Snake River plain Regional Aquifer-System Analysis in Idaho and eastern Oregon

    Science.gov (United States)

    Lindholm, G.F.

    1996-01-01

    Regional aquifers underlying the 15,600-square-mile Snake River Plain in southern Idaho and eastern Oregon was studied as part of the U.S. Geological Survey's Regional Aquifer-System Analysis program. The largest and most productive aquifers in the Snake River Plain are composed of Quaternary basalt of the Snake River Group, which underlies most of the 10,8000-square-mile eastern plain. Aquifer tests and simulation indicate that transmissivity of the upper 200 feet of the basalt aquifer in the eastern plain commonly ranges from about 100,000 to 1,000,000 feet squared per day. However, transmissivity of the total aquifer thickness may be as much as 10 million feet squared per day. Specific yield of the upper 200 feet of the aquifer ranges from about 0.01 to 0.20. Average horizontal hydraulic conductivity of the upper 200 feet of the basalt aquifer ranges from less than 100 to 9,000 feet per day. Values may be one to several orders of magnitude higher in parts in individual flows, such as flow tops. Vertical hydraulic conductivity is probably several orders of magnitude lower than horizontal hydraulic conductivity and is generally related to the number of joints. Pillow lava in ancestral Snake River channels has the highest hydraulic conductivity of all rock types. Hydraulic conductivity of the basalt decreases with depth because of secondary filling of voids with calcite and silica. An estimated 80 to 120 million acre-feet of water is believed to be stored in the upper 200 feet of the basalt aquifer in the eastern plain. The most productive aquifers in the 4,800-square-mile western plain are alluvial sand and gravel in the Boise River valley. Although aquifer tests indicate that transmissivity of alluvium in the Boise River valley ranges from 5,000 to 160,000 feet squared per day, simulation suggests that average transmissivity of the upper 500 feet is generally less than 20,000 feet squared per day. Vertically averaged horizontal hydraulic conductivity of the upper

  20. Change of ancient hydrology net in Northeast China Plain

    Institute of Scientific and Technical Information of China (English)

    Hui QU; Yu CHU; Fenglong ZHANG; Fuli QI; Xiangkui YANG

    2006-01-01

    Comparing with lithofacies palaeogeography of several great plains, the authors analyzed four great plains in Quaternary diastrophism, the sedimentary facies, sedimentary environment and their evolution from the independent embryonic and river system of ancient Heilongjiang finally to the Halar highland, Songnen Plain, Sanjiang Plain, the Xingkai Lake Plain and various river systems, collected the unification outside the system of Heilongjiang River to release into the sea, south ancient Xialiao River finally piracy Dongliao River, Xialiao River had released into the sea the ancient water law vicissitude and the evolved rule.

  1. An experimental investigation on air-side performances of finned tube heat exchangers for indirect air-cooling tower

    Directory of Open Access Journals (Sweden)

    Du Xueping

    2014-01-01

    Full Text Available A tremendous quantity of water can be saved if the air cooling system is used, comparing with the ordinary water-cooling technology. In this study, two kinds of finned tube heat exchangers in an indirect air-cooling tower are experimentally studied, which are a plain finned oval-tube heat exchanger and a wavy-finned flat-tube heat exchanger in a cross flow of air. Four different air inlet angles (90°, 60 °, 45°, and 30° are tested separately to obtain the heat transfer and resistance performance. Then the air-side experimental correlations of the Nusselt number and friction factor are acquired. The comprehensive heat transfer performances for two finned tube heat exchangers under four air inlet angles are compared. For the plain finned oval-tube heat exchanger, the vertical angle (90° has the worst performance while 45° and 30° has the best performance at small ReDc and at large ReDc, respectively. For the wavy-finned flat-tube heat exchanger, the worst performance occurred at 60°, while the best performance occurred at 45° and 90° at small ReDc and at large ReDc, respectively. From the comparative results, it can be found that the air inlet angle has completely different effects on the comprehensive heat transfer performance for the heat exchangers with different structures.

  2. Effect of the sequence of tube rolling in a tube bundle of a shell and tube heat exchanger on the stress-deformed state of the tube sheet

    Science.gov (United States)

    Tselishchev, M. F.; Plotnikov, P. N.; Brodov, Yu. M.

    2015-11-01

    Rolling the tube sheet of a heat exchanger with U-shaped tubes, as exemplified by the vapor cooler GP-24, was simulated. The simulation was performed using the finite element method with account of elas- tic-plastic properties of the tube and tube sheet materials. The simulation consisted of two stages; at the first stage, maximum and residual contact stress in the conjunction of a separate tube and the tube sheet was determined using the "equivalent sleeve" model; at the second stage, the obtained contact stress was applied to the hole surface in the tube sheet. Thus, different tube rolling sequences were simulated: from the center to the periphery of the tube sheet and from the periphery to the center along a spiral line. The studies showed that the tube rolling sequence noticeably influences the value of the tube sheet residual deflection for the same rolling parameters of separate tubes. Residual deflection of the tube sheet in different planes was determined. It was established that the smallest residual deflection corresponds to the tube rolling sequence from the periphery to the center of the tube sheet. The following dependences were obtained for different rolling sequences: maximum deformation of the tube sheet as a function of the number of rolled tubes, residual deformation of the tube sheet along its surface, and residual deflection of the tube sheet as a function of the rotation angle at the periphery. The preferred sequence of tube rolling for minimizing the tube sheet deformation is indicated.

  3. Infrared imaging of LED lighting tubes and fluorescent tubes

    Science.gov (United States)

    Siikanen, Sami; Kivi, Sini; Kauppinen, Timo; Juuti, Mikko

    2011-05-01

    The low energy efficiency of conventional light sources is mainly caused by generation of waste heat. We used infrared (IR) imaging in order to monitor the heating of both LED tube luminaires and ordinary T8 fluorescent tubes. The IR images showed clearly how the surface temperatures of the fluorescent tube ends quickly rose up to about +50...+70°C, whereas the highest surface temperatures seen on the LED tubes were only about +30...+40°C. The IR images demonstrated how the heat produced by the individual LED chips can be efficiently guided to the supporting structure in order to keep the LED emitters cool and hence maintain efficient operation. The consumed electrical power and produced illuminance were also recorded during 24 hour measurements. In order to assess the total luminous efficacy of the luminaires, separate luminous flux measurements were made in a large integrating sphere. The currently available LED tubes showed efficacies of up to 88 lm/W, whereas a standard "cool white" T8 fluorescent tube produced ca. 75 lm/W. Both lamp types gave ca. 110 - 130 lx right below the ceiling-mounted luminaire, but the LED tubes consume only 40 - 55% of the electric power compared to fluorescent tubes.

  4. Diffuser Augmented Horizontal Axis Tidal Current Turbines

    Directory of Open Access Journals (Sweden)

    Nasir Mehmood

    2012-09-01

    Full Text Available The renewal energy technologies are increasingly popular to ensure future energy sustenance and address environmental issues. The tides are enormous and consistent untapped resource of renewable energy. The growing interest in exploring tidal energy has compelling reasons such as security and diversity of supply, intermittent but predictable and limited social and environmental impacts. The tidal energy industry is undergoing an increasing shift towards diffuser augmented turbines. The reason is the higher power output of diffuser augmented turbines compared to conventional open turbines. The purpose of this study is to present a comprehensive review of diffuser augmented horizontal axis tidal current turbines. The components, relative advantages, limitations and design parameters of diffuser augmented horizontal axis tidal current turbines are presented in detail. CFD simulation of NACA 0016 airfoil is carried out to explore its potential for designing a diffuser. The core issues associated with diffuser augmented horizontal axis tidal current turbines are also discussed.

  5. HORIZONTAL WELL DRILL-IN FLUIDS

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1998-12-01

    Full Text Available Main objective of horizontal driling is to place a drain-hole for a long distance within the pay zone to enhance productivity or injectivity. In drilling horizontal wells, more serious problems appear than in drilling vertical wells. These problems are: poor hole cleaning, excessive torque and drag, hole filling, pipe stucking, wellbore instability, loss of circulation, formation damage, poor cement job, and difficulties at logging jobs. From that reason, successful drilling and production of horizontal well depends largely on the fluid used during drilling and completion phases. Several new fluids, that fulfill some or all of required properties (hole cleaning, cutting suspension, good lubrication, and relative low formation damage, are presented in this paper.

  6. Horizontal stirring in the global ocean

    CERN Document Server

    Hernández-Carrasco, I; Hernández-García, E; Turiel, A

    2011-01-01

    Horizontal mixing and the distribution of coherent structures in the global ocean are analyzed using Finite-Size Lyapunov Exponents (FSLE), computed for the surface velocity field derived from the Ocean general circulation model For the Earth Simulator (OFES). FSLEs measure horizontal stirring and dispersion; additionally, the transport barriers which organize the oceanic flow can roughly be identified with the ridges of the FSLE field. We have performed a detailed statistical study, particularizing for the behaviour of the two hemispheres and different ocean basins. The computed Probability Distributions Functions (PDFs) of FSLE are broad and asymmetric. Horizontal mixing is generally more active in the northern hemisphere than in the southern one. Nevertheless the Southern Ocean is the most active ocean, and the Pacific the less active one. A striking result is that the main currents can be classified in two 'activity classes': Western Boundary Currents, which have broad PDFs with large FSLE values, and Eas...

  7. Surface-compositional Properties of Lava Plains in Syria-Thaumasia Block, Mars

    Science.gov (United States)

    Huang, J.; Xiao, L.; Kraft, M. D.; Christensen, P. R.; Edwards, C. S.; Ruff, S. W.; Dohm, J.

    2012-12-01

    Mars has a long and complex volcanic history (Greeley and Spudis, 1981; Carr, 2006). Among abundant plain-style volcanism and various edifices, Tharsis bulge is a prominent and long-lasting (Werner, 2009) volcanic province. However, there is little report about compositional variations before and after Tharsis uplift. The Syria- Thaumasia block (STB) is a complex tectono-volcanic province related to the Tharsis bulge. Understanding its formation is critical to characterizing the early history and planetary evolution of Mars. The STB lies at the southern edge of Tharsis bulge. It consists of lava plains (Syria, Solis, Sinai and Thaumasia Plana) bounded by an arcuate region of higher topography (Thaumasia Highlands, Melas Dorsa and Coprates Rise) and Valles Marineris to the north. Previous work on surface thermophysical properties (Christensen, 1988; Jakosky et al., 2000; Putzig and Mellon, 2007) and visible/near infrared and thermal infrared remote sensing spectroscopic compositional analysis (Bandfield, 2000; Bibring et al., 2006; Rogers and Christensen, 2007) had been done only in a global scale, but regional study of both surface thermophysical properties and compositions for each of the distinct lava plains in STB is lacking. In this study, we characterize a variety of volcanic features, including lava tubes, channels and their relationships with wrinkle ridges within lava plains using THEMIS infrared data (100 m/pixel: Christensen et al., 2004), CTX data (6 m/pixel: Malin et al., 2007) and HiRISE data (25 cm/pixel: McEwen et al., 2007). We assessed the surface thermophysical properties and compositions of lava plains using TES data (Christensen et al., 2001). The geomorphic features imply the lava emplacement mechanisms, while their relationships indicate the chronologic relationships between Tharsis uplift and lava emplacement. The compositional results show variations within the lava plains (Table 1), while the thermophysical results show the compositional

  8. Validation of a Model for Ice Formation around Finned Tubes

    Directory of Open Access Journals (Sweden)

    Kamal A. R. Ismai

    2016-09-01

    Full Text Available Phase change materials although attaractive option for thermal storage applications its main drawback is the slow thermal response during charging and discharging processes due to their low thermal conductivity. The present study validates a model developed by the authors some years ago on radial fins as a method to meliorate the thermal performance of PCM in horizontal storage system. The developed model for the radial finned tube is based on pure conduction, the enthalpy approach and was discretized by the finite difference method. Experiments were realized specifically to validate the model and its numerical predictions.

  9. Explosive welding of a tube into a tube sheet

    Energy Technology Data Exchange (ETDEWEB)

    Green, Sheryll C. (London, OH); Linse, Vonne D. (Columbus, OH)

    1978-10-03

    A cartridge containing an explosive charge is placed within a tube assembled within a tube sheet. The charge is detonated through use of a detonator cord containing a minimum but effective amount of explosive material. The cord is contained inside a tubular shield throughout most of its length within the cartridge. A small length of the cord extends beyond the tubular shield to contact and detonate the explosive charge in its rear portion near the cartridge base. The cartridge base is provided of substantial mass and thickness in respect to side and front walls of the cartridge to minimize bulging beyond the rear face of the tube sheet. For remote activation an electrically activated detonator of higher charge density than the cord is attached to the cord at a location spaced from the tube sheet, cartridge and tube.

  10. Explosive welding of a tube into a tube sheet

    Energy Technology Data Exchange (ETDEWEB)

    Green, S.C.; Linse, V.D.

    1978-10-03

    A cartridge containing an explosive charge is placed within a tube assembled within a tube sheet. The charge is detonated through use of a detonator cord containing a minimum but effective amount of explosive material. The cord is contained inside a tubular shield throughout most of its length within the cartridge. A small length of the cord extends beyond the tublar shield to contact and detonate the explosive charge in its rear portion near the cartridge base. The cartridge base is provided of substantial mass and thickness in respect to side and front walls of the cartridge to minimize bulging beyond the rear face of the tube sheet. For remote activation an electrically activated detonator of higher charge density than the cord is attached to the cord at a location spaced from the tube sheet, cartridge and tube.

  11. Nasogastric tube syndrome induced by an indwelling long intestinal tube.

    Science.gov (United States)

    Sano, Naoki; Yamamoto, Masayoshi; Nagai, Kentaro; Yamada, Keiichi; Ohkohchi, Nobuhiro

    2016-04-21

    The nasogastric tube (NGT) has become a frequently used device to alleviate gastrointestinal symptoms. Nasogastric tube syndrome (NTS) is an uncommon but potentially life-threatening complication of an indwelling NGT. NTS is characterized by acute upper airway obstruction due to bilateral vocal cord paralysis. We report a case of a 76-year-old man with NTS, induced by an indwelling long intestinal tube. He was admitted to our hospital for treatment of sigmoid colon cancer. He underwent sigmoidectomy to release a bowel obstruction, and had a long intestinal tube inserted to decompress the intestinal tract. He presented acute dyspnea following prolonged intestinal intubation, and bronchoscopy showed bilateral vocal cord paralysis. The NGT was removed immediately, and tracheotomy was performed. The patient was finally discharged in a fully recovered state. NTS be considered in patients complaining of acute upper airway obstruction, not only with a NGT inserted but also with a long intestinal tube.

  12. Effect of gravity on the liquid film surrounding a bubble translating in a tube

    Science.gov (United States)

    Atasi, Omer; Khodaparast, Sepideh; Scheid, Benoit; Stone, Howard A.

    2016-11-01

    The motion of confined elongated bubbles in small diameter tubes filled with viscous liquid is a ubiquitous problem relevant to many industrial and medical applications such as lubrication, oil extraction and the treatment of pulmonary disorders. As a confined bubble proceeds into a liquid-filled tube a thin film of liquid is formed on the tube wall. For negligible inertia and buoyancy (Bo, Re = 0), the thickness of this film depends only on the capillary number Ca. However, gravitational effects are not negligible for horizontal tubes of millimeter-scale diameter, corresponding to a finite Bond number Bo. We perform experiments and theoretical analysis to investigate the effect of Bo on the thin film thickness. Several values of Bo are tested experimentally by changing the tube diameter. Due to gravity, the film deposited on the upper wall of the channel is thinner than the film at the bottom wall, and the bubble is inclined toward the bottom of the tube as it translates along the tube. The inclination angle increases with increasing Bo and Ca. Our theoretical analysis shows that this effect is caused by the bubble being off-center in the tube at finite values of Bo. F.R.S. - FNRS.

  13. Theoretical and experimental validation of evacuated tubes directly coupled with solar still

    Science.gov (United States)

    Panchal, H. N.; Thakkar, H.

    2016-11-01

    Experimental study of evacuated tubes coupled solar still in the climatic conditions of Mehsana, a region of North Gujarat, India during summer and winter climate conditions has been made. Experimental setup was made by authors. Fourteen double-walled hard borosilicate glass tubes have been used. Evacuated tubes were inclined at angle of 45° from horizontal. Outer tubes of evacuated tubes were transparent, inner tubes were coated with a selective coating of Al-Ni/Al compound for better solar radiation absorption and minimum emittance. It has been shown that evacuated tube attachments to the solar still increased the water temperature inside the solar still for increment in the generation of distillate output. Evacuated tubes coupled solar still is not only produce distilled water during sunshine hours, but also off-sunshine hours due to heat storage effect. For the validation of the experimental results, a theoretical model is proposed based on the fundamentals of heat and mass transfer equations for solar still glass cover, water in basin and basin bottom. Two main statistical parameters—root mean square error and mean bias error—were calculated to compare the results of experiments and theoretical analysis. Closed matching of the experimental and theoretical results has been found.

  14. El horizonte estético

    OpenAIRE

    Perniola, Mario

    2004-01-01

    La existencia de un horizonte estético depende de la coexistencia de múltiples factores de distinta naturaleza que interactúan entre ellos. No bastan las reflexiones en torno a lo bello y al arte para crear un horizonte estético. La palabra “estética” es introducida en el Settecento por la filosofía para indicar una articulación disciplinar propia que pudiera ubicarse cerca de la lógica; esta circunstancia histórica, sin embargo, no debe hacernos olvidar que la filosofía es desde su nacimient...

  15. Fourth international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Tuomisto, H. [ed.] [IVO Group, Vantaa (Finland); Purhonen, H. [ed.] [VTT, Espoo (Finland); Kouhia, V. [ed.] [Lappeenranta Univ. of Technology (Finland)

    1997-12-31

    The general objective of the International Seminars of Horizontal Steam Generator Modelling has been the improvement in understanding of realistic thermal hydraulic behaviour of the generators when performing safety analyses for VVER reactors. The main topics presented in the fourth seminar were: thermal hydraulic experiments and analyses, primary collector integrity, feedwater distributor replacement, management of primary-to-secondary leakage accidents and new developments in the VVER safety technology. The number of participants, representing designers and manufacturers of the horizontal steam generators, plant operators, engineering companies, research organizations, universities and regulatory authorities, was 70 from 10 countries.

  16. Horizontal Roll Vortices and Crown Fires.

    Science.gov (United States)

    Haines, Donald A.

    1982-06-01

    Observational evidence from nine crown fires suggests that horizontal roll vortices are a major mechanism in crown-fire spread. Post-burn aerial photography indicates that unburned tree-crown streets are common with crown fire. Investigation of the understory of these crown streets after two fires showed uncharred tree trunks along a center line. This evidence supports a hypothesis of vortex action causing strong downward motion of air along the streets. Additionally, photographs of two ongoing crown fires show apparent horizontal roll vortices. Discussion also includes laboratory and numerical studies in fluid dynamics that may apply to crown fires.

  17. A newly developed open-end intracranial hematoma drainage tube

    Institute of Scientific and Technical Information of China (English)

    Chao He; Nongnaphat Wanussakul; Dong Yang; Tianya Wu; Ming Zhao

    2016-01-01

    Methods:The newly developed device consists of two parts:the plunger and barrel. On one side, the barrel is bullet shaped with an opening tip. The plunger is located in the middle cavity of the tube barrel and extended out at the open-end. It was designed for strengthening the tube barrel and for convenience in performing the drainage procedure. It can be used by inserting the drainage tube into the lesion and pulling out the plunger, whereby blood will forcefully rise up inside the barrel, providing a satisfactory outcome. It is made for effusion drainage purposes. During the procedure, the drainage tip is placed at the deepest part of the intracranial hematoma to completely drain the blood. Moreover, the plunger fits tightly in the tube, preventing leakage during the operation. With the use of the device, brain can be separated. In addition, the device can help reduce the risk of cerebral damage because of the small operating area. The barrel sidewall has matching opening holes bilaterally and equally for exchanging substances between the inner and outer parts. The overlapping ratio in each horizontal pair is around 1/3–1/2. Each pair on the opposite side will form a different pressure. Thus, the opening holes will not easily get blocked with blood clot. Results: Blood and accumulated liquid from the deepest part of the intracranial hematoma can be directly drawn through the drainage tube without damaging a large area. The tube does not get blocked easily and allows for complete removal of the hematoma. Conclusions:The device is asuitable instrument for clinical application.

  18. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL ABSORBER STRIPS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2007-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal strips. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...... (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured...... rate, properties of solar collector fluid, solar collector fluid inlet temperature and collector tilt angle are shown. The flow distribution through the absorber fins is uniform if high flow rates are used. By decreased flow rate and decreased content of glycol in the glycol/water mixture used as solar...

  19. Piezoelectric Rotary Tube Motor

    Science.gov (United States)

    Fisher, Charles D.; Badescu, Mircea; Braun, David F.; Culhane, Robert

    2011-01-01

    A custom rotary SQUIGGLE(Registered TradeMark) motor has been developed that sets new benchmarks for small motor size, high position resolution, and high torque without gear reduction. Its capabilities cannot be achieved with conventional electromagnetic motors. It consists of piezoelectric plates mounted on a square flexible tube. The plates are actuated via voltage waveforms 90 out of phase at the resonant frequency of the device to create rotary motion. The motors were incorporated into a two-axis postioner that was designed for fiber-fed spectroscopy for ground-based and space-based projects. The positioner enables large-scale celestial object surveys to take place in a practical amount of time.

  20. Primary Fallopian Tube Carcinoma

    Directory of Open Access Journals (Sweden)

    Prasad K Shetty

    2011-01-01

    Full Text Available Primary Fallopian Tube Carcinoma (PFTC is rare and accounts for about 0.3% of all gynecologic cancers. Less than 1500 cases have been reported in the literature. It arises in postmenopausal women and typically presents with abdominal pelvic pain, vaginal bleeding and watery discharge. However, a correct diagnosis is rarely achieved preoperative, and in many cases, the diagnosis is made after incidental surgery for unrelated conditions commonly being ovarian carcinoma . Compared with ovarian carcinoma, PFTC more often presents at early stages, but it has a worse prognosis. PFTC is usually managed in the same manner as ovarian cancer. We report a case of Left PFTC that presented as Left ovarian mass, and we briefly review the literature.

  1. A new flooding scheme by horizontal well in thin heavy oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H.; Zhang, H.; Wang, M. [China Univ. of Petroleum, Beijing (China). MOE Key Laboratory of Petroleum Engineering ; Wang, Z. [Shengli Oil Field Co. (China). Dept. of Science and Technology]|[SINOPEC, Shengli (China)

    2008-10-15

    This paper presented a new flooding scheme for single horizontal wells that could improve recovery from thin marginal heavy oil reservoirs or from offshore reservoirs. The scheme involved the use of a multiple tubing string completion in a single wellbore. Special packers were installed within the long completion horizontal interval to establish an injection zone and a production zone. The new flooding scheme also involved simultaneous injection and production. Numerical simulation of the reservoir was used to determine the thickness of the formation and the lower limitation for different viscosities and the optimum time to start steam flooding after steam soaking by economic oil/steam ratio. The peak recovery efficiency of steam flooding was shown to occur when the length of separation section ratio is 0.15 to 0.2. It was concluded that high thermal efficiency in horizontal wells with long completion intervals can be maintained by alternating between steam soaking and steam flooding. Suitable alternation time to steam flooding is a seventh cycle for horizontal wells. Water cut and pressure difference will increase the steam injection rate, and thereby improve the oil production rate. The suitable injection rate for steam flooding is 2.4 t/d.ha.h because of its slow pressure change. 11 refs., 7 figs.

  2. Modelling of Heat Transfer Phenomena for Vertical and Horizontal Configurations of In-Pool Condensers and Comparison with Experimental Findings

    OpenAIRE

    2010-01-01

    Decay Heat Removal (DHR) is a fundamental safety function which is often accomplished in the advanced LWRs relying on natural phenomena. A typical passive DHR system is the two-phase flow, natural circulation, closed loop system, where heat is removed by means of a steam generator or heat exchanger, a condenser, and a pool. Different condenser tube arrangements have been developed for applications to the next generation NPPs. The two most used configurations, namely, horizontal and vertica...

  3. Flaming on YouTube

    NARCIS (Netherlands)

    Moor, Peter J.; Heuvelman, A.; Verleur, R.

    2010-01-01

    In this explorative study, flaming on YouTube was studied using surveys of YouTube users. Flaming is defined as displaying hostility by insulting, swearing or using otherwise offensive language. Three general conclusions were drawn. First, although many users said that they themselves do not flame,

  4. Interpreting Shock Tube Ignition Data

    Science.gov (United States)

    2003-10-01

    times only for high concentrations (of order 1% fuel or greater). The requirements of engine (IC, HCCI , CI and SI) modelers also present a different...Paper 03F-61 Interpreting Shock Tube Ignition Data D. F. Davidson and R. K. Hanson Mechanical Engineering ... Engineering Department Stanford University, Stanford CA 94305 Abstract Chemical kinetic modelers make extensive use of shock tube ignition data

  5. Flaming on YouTube

    NARCIS (Netherlands)

    Moor, Peter J.; Heuvelman, Ard; Verleur, Ria

    2010-01-01

    In this explorative study, flaming on YouTube was studied using surveys of YouTube users. Flaming is defined as displaying hostility by insulting, swearing or using otherwise offensive language. Three general conclusions were drawn. First, although many users said that they themselves do not flame,

  6. Flow distribution in a solar collector panel with horizontally inclined absorber strips

    DEFF Research Database (Denmark)

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2007-01-01

    dynamics (CFD) calculations. Further, experimental investigations of a 12.5 m(2) solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured...... rate, properties of solar collector fluid, solar collector fluid inlet temperature and collector tilt angle are shown. The flow distribution through the absorber fins is uniform if high flow rates are used. By decreased flow rate and decreased content of glycol in the glycol/water mixture used as solar...

  7. Carrying capacity for the electromagnetic suspension low-speed maglev train on the horizontal curve

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Aiming at the lateral dislocation between the electromagnets and the rails on a horizontal curve,we investigated a single magnetic bogie of the maglev train in this paper.The magnetic levitation and guidance forces supplied by the suspension modules were deduced by the flux tube method.According to the dynamic equilibrium equations of the maglev train on the curved track with cant,several major factors that influence the carrying capacity were analyzed,and the formula of the carrying capacity was presented.The results provide a theoretical reference for the design of maglev train.

  8. Performance Evaluation of Plate-Fin-And Tube Heat Exchanger with Wavy Fins- A Review

    Directory of Open Access Journals (Sweden)

    Sandip S. Kale

    2014-09-01

    Full Text Available The plate fin-and-tube heat exchangers are widely used in variety of industrial applications, particularly in the heating, air-conditioning and refrigeration, HVAC industries. In most cases the working fluid is liquid on the tube side exchanging heat with a gas, usually air. It is seen that the performance of heat exchangers can be greatly increased with the use of unconventionally shaped flow passages such as plain, perforated offset strip, louvered, wavy, vortex generator and pin. The current study is focused on wavy-fin. The wavy surface can lengthen the path of airflow and cause better airflow mixing. In order to design better heat exchangers and come up with efficient designs, a thorough understanding of the flow of air in these channels is required. Hence this study focuses on the heat transfer and friction characteristics of the air side for wavy fin and tube heat exchanger.

  9. Analysis of fouling characteristic in enhanced tubes using multiple heat and mass transfer analogies☆

    Institute of Scientific and Technical Information of China (English)

    Zepeng Wang; Guanqiu Li; Jingliang Xu; Jinjia Wei; Jun Zeng; Decang Lou; Wei Li

    2015-01-01

    This paper provides a comprehensive analysis on cooling tower fouling data taken from seven 15.54 mm I.D. helically ribbed, copper tubes and a plain tube at Re=16000. There are two key processes during fouling formation:fouling deposition and fouling removal, which can be determined by mass transfer and fluid friction respectively. The mass transfer coefficient can be calculated through three analogies:Prandtl analogy, Von–Karman analogy, and Chilton–Colburn analogy. Based on our analyses, Von–Karman analogy is the optimized analogy, which can well predict the formation of cooling tower fouling. Series of semi-theoretical fouling correlations as a function of the product of area indexes and efficiency indexes were developed, which can be applicable to different internally ribbed geometries. The correlations can be directly used to assess the fouling potential of enhanced tubes in actual cooling tower water situations.

  10. A Case Study of Horizontal Teacher Evaluation.

    Science.gov (United States)

    Johnson, Trav D.

    Horizontal teacher evaluation increases understanding of teaching through the critical examination of educational goals and classroom practices. This examination includes teachers' classroom observations of one another coupled with in-depth teacher conversations or dialogue about teaching aims and practices. A qualitative case study of a…

  11. Third international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues.

  12. Parametric study for horizontal steam generator modelling

    Energy Technology Data Exchange (ETDEWEB)

    Ovtcharova, I. [Energoproekt, Sofia (Bulgaria)

    1995-12-31

    In the presentation some of the calculated results of horizontal steam generator PGV - 440 modelling with RELAP5/Mod3 are described. Two nodalization schemes have been used with different components in the steam dome. A study of parameters variation on the steam generator work and calculated results is made in cases with separator and branch.

  13. Evaluation of horizontal magnification on panoramic images

    Directory of Open Access Journals (Sweden)

    Maryam Raoof

    2013-01-01

    Full Text Available Aims: This study evaluated the horizontal magnification of images taken from adults and pediatrics with PM 2002 CC Planmeca analogue machine. Materials and Methods: A series of 120 panoramic radiographs were obtained of 60 adults and 60 pediatrics. For all patients, negative impressions were used to make positive casts of the teeth. A caliper was used to measure the maximum mesiodistal length of the buccal surface of all teeth except canines on both casts and radiographs. The horizontal magnification factor was calculated for incisor, premolar, and molar regions by dividing the values obtained from the casts by the values obtained from the radiographs. Statistical Analysis: Independent t-test and one-way analysis of variance (ANOVA were used. Results: The results indicated that with regard to adults, maxillary and mandibular incisor regions, unlike the other two sessions, didn′t show significant difference of the mean magnification of horizontal dimension (P = 0.5. In pediatrics, the comparison between mean magnification factors of all subgroups showed significant difference (P < 0.0001. Despite the adults′ radiographs, the results of pediatrics′ radiographs showed significantly higher magnification than the index listed by the manufacturer of the radiographic machine used. Conclusion: The present study results point to the fact that PM 2002 CC Proline panoramic machine makes possible precise measurements on radiographs of adults′ jaws in the horizontal dimension.

  14. Fermion mass hierarchy and global horizontal symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Gelmini, G.B.; Gerard, J.M.; Yanagida, T.; Zoupanos, G. (European Organization for Nuclear Research, Geneva (Switzerland))

    1984-02-02

    We present a mechanism for quark mass generation in zeroth order using induced representations rather than the minimization of the horizontal potential. Using a simplicity criterion, we derive a realistic mass matrix. We also discuss a possible application of the mechanism to various models.

  15. Horizontal gene transfer in the phytosphere

    NARCIS (Netherlands)

    Elsas, van J.D.; Turner, S.; Bailey, M.J.

    2003-01-01

    Here, the ecological aspects of gene transfer processes between bacteria in the phytosphere are examined in the context of emerging evidence for the dominant role that horizontal gene transfer (HGT) has played in the evolutionary shaping of bacterial communities. Moreover, the impact of the putative

  16. Flow mapping for ESS horizontal target

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Y.; Kikura, H.; Taishi, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Flow behaviour for ESS horizontal target is studied experimentally using two dimensional water model. A velocity field of stationary flow in reaction zone has been obtained. Three dimensional effect was also studied as a spanwise flow structure. (author) 3 figs., 3 refs.

  17. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...

  18. Teaching Activities on Horizontal Nuclear Proliferation.

    Science.gov (United States)

    Zola, John

    1990-01-01

    Provides learning activities concerning the horizontal proliferation of nuclear weapons. Includes step-by-step directions for four activities: (1) the life cycle of nuclear weapons; (2) nuclear nonproliferation: pros and cons; (3) the nuclear power/nuclear weapons connection; and (4) managing nuclear proliferation. (NL)

  19. Mud and cement for horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Zurdo, C.; Georges, C.; Martin, M.

    1986-01-01

    High-angle and horizontal well bores raise many questions concerning the characteristics of mud and cement. This paper is a summary of the authors' knowledge and work on these two subjects. For all research carried out, large or full-scale laboratory test plants were used. Cutting transport is not only a problem in horizontal conditions but hole angles of 25 to 65/sup 0/ can be even more critical when parameters such as mud rheological properties and velocities are not optimized. Drilling a long horizontal drain creates a dynamic annulus pressure unbalance. This can lead to a loss and kick situation. Two test benches were thus used to obtain a good understanding of the inefficiency of conventional plugging methods and of the difficulties of gas migration control in subhorizontal well bores. High concentrations of LCM, high rheological properties of fluids and low flow rates increase the changes of solving the first problem. The results of the second bench demonstrate the difficulties of annulus gas evacution for angles varying from 90 to 100 degrees, or from over-gauged sections in horizontal holes.

  20. Boiling heat transfer correlations for refrigerant mixtures flowing inside micro-fin tubes

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan ZHANG; Xingqun ZHANG; Yunguang CHEN; Xiuling YUAN

    2008-01-01

    Based on experimental results of ternary non-azeotropic refrigerant mixture R417A flowing and boiling in one smooth and two internally grooved horizontal tubes with different geometrical parameters, a boiling heat transfer correlations was developed for refrigerant mix-tures flowing inside micro-fin tubes by applying the enhancement factor in the present modified-Kattan model which was modified by the experimental data of R417A in a smooth tube. The comparison between the calculation and the experimental results indicates that the prediction by the present correlations is in good agreement with the experiment of refrigerant mixtures inside different micro-fin tubes with a standard deviation of ± 30% for vapor qualities below 80%.

  1. Simulation of flow across complicated domain between tube bundles by the discrete vortex method

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    On the basis of the analysis of numerical simulation methods for the complicated domain between tube bundles, an improved Lagragian discrete vortex method (DVM) and corresponding algorithm are put forward to solve the practical difficulties of flow across tube bundles. With this method the amount of vortices can be reduced considerably, which makes quick calculation possible. Applied to the practical configuration of horizontal tube bundles, the DVM simulation is carried out and compared with the experimental results. Both the transient flow field and the profile of mean velocity and fluctuations are in good agreement with experimental results, which indicate that the DVM is suitable for the simulation of single-phase flow across tube bundles.

  2. Water-storage-tube systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hemker, P.

    1981-12-24

    Passive solar collection/storage/distribution systems were surveyed, designed, fabricated, and mechanically and thermally tested. The types studied were clear and opaque fiberglass tubes, metal tubes with plastic liners, and thermosyphoning tubes. (MHR)

  3. Vidicon storage tube electrical input/output

    Science.gov (United States)

    Lipoma, P.

    1972-01-01

    Electrical data storage tube is assembled from standard vidicon tube using conventional amplification and control circuits. Vidicon storage tube is simple, inexpensive and has an erase and preparation time of less than 5 microseconds.

  4. Experimental investigation of axially loaded steel fiber reinforced high strength concrete-filled steel tube columns

    Institute of Scientific and Technical Information of China (English)

    卢亦焱; 李娜; 李杉; 梁鸿骏

    2015-01-01

    An experimental study on the compressive behavior of steel fiber reinforced concrete-filled steel tube columns is presented. Specimens were tested to investigate the effects of the concrete strength, the thickness of steel tube and the steel fiber volume fraction on the ultimate strength and the ductility. The experimental results indicate that the addition of steel fibers in concrete can significantly improve the ductility and the energy dissipation capacity of the concrete-filled steel tube columns and delay the local buckling of the steel tube, but has no obvious effect on the failure mode. It has also been found that the addition of steel fibers is a more effective method than using thicker steel tube in enhancing the ductility, and more advantageous in the case of higher strength concrete. An analytical model to estimate the load capacity is proposed for steel tube columns filled with both plain concrete and steel fiber reinforced concrete. The predicted results are in good agreement with the experimental ones obtained in this work and literatures.

  5. Investigation of the effects of baffle orientation, baffle cut and fluid viscosity on shell side pressure drop and heat transfer coefficient in an e-type shell and tube heat exchanger

    OpenAIRE

    Mohammadi, Koorosh

    2011-01-01

    The commercial CFD code FLUENT is used to determine the effect of baffle orientation and baffle cut as well as viscosity of the working fluid on the shell-side heat transfer and pressure drop of a shell and tube heat exchanger. The shell and tube heat exchangers considered follow the TEMA standards. The investigation has been completed in three stages: 1. The shell and tube heat exchanger consists of 660 plain tubes with fixed outside diameter which are arranged in a triangular layout. Hor...

  6. Prediction of thermal hydraulic characteristics inside the storage tank of a horizontal condensation heat exchanger using MARS-KS

    Science.gov (United States)

    Shin, Byung Soo; Seul, Kwang Won; Do, Kyu Sik; Reactor system evaluation Team

    2012-11-01

    The performance of a horizontal condensation heat exchanger is determined by the condensation heat transfer inside the heat exchanger tubes, convective or boiling heat transfer outside the tubes and flow characteristics in the storage tank. The flow characteristics in the tank are important factors to determine the heat transfer rate outside the tubes. The objective of this work is to develop the method to predict the heat transfer rate outside the tubes properly using MARS-KS code. Two different results from MARS-KS were compared with simplified experimental results in other works to estimate the capacity of MARS-KS. One was by a typical 1D nodalization but another was by a 3D nodalization considering natural circulation in the storage tank. Then, to eliminate the effect of condensation heat transfer inside the tubes, the experimental results on temperature profiles were applied to the inside wall of tubes as boundary conditions. As the result, the 3-D nodalization model had good predictions with experimental results in regard of wall temperature, heat flux and heat transfer coefficients. It was also confirmed that the natural circulation flow was developed inside the storage tank.

  7. Studi Numerik Pengaruh Panjang Rectangular Obstacle Terhadap Perpindahan Panas Pada Staggered Tube Banks

    Directory of Open Access Journals (Sweden)

    Hastama Arinta Fanny

    2014-09-01

    Full Text Available Alat penukar panas merupakan komponen yang sangat penting dari banyak proses industri dan peralatan yang meliputi berbagai aplikasi teknik. Meningkatkan kesadaran untuk pemanfaatan sumber daya energi yang efektif, meminimalkan biaya operasional dan pemeliharaan operasi murah telah menyebabkan perkembangan dari alat penukar panas yang efisien seperti alat penukar panas kompak. Performa alat penukar panas kompak bergantung pada pola permukaan fin, yakni plain fins dan wavy fins Permukaan plain fin yang datar membuat aliran membutuhkan waktu yang relatif lebih lama untuk memaksimalkan perpindahan panas jika dibandingkan pada bentuk wavy fin yang bergelombang. Selain merubah pola permukaan fin, upaya lain untuk bisa memaksimalkan proses perpindahan panas pada plain fins juga dapat dibentuk dengan penambahan obstacle pada permukaannya. Performa alat penukar panas dengan obstacle dapat diketahui dengan menganalisa pola aliran dan perpindahan panas yang terjadi. Penelitian ini dilakukan dengan metode simulasi numerik dengan menggunakan bantuan software Fluent 6.3.26. Simulasi ini dikondisikan dengan menggunakan model 2D-steady flow, turbulensi k-ε RNG dan metode second-order upwind scheme. Pada penelitian ini yang divariasikan adalah panjang dari rectangular obstacle, yaitu 1,6mm, 2,5mm, 5mm yang terletak pada kemiringan 135o berdasarkan titik pusat tube, diukur dari stagnation point pada staggered tube bank. Fluida kerja yang digunakan adalah udara yang dimodelkan sebagai gas ideal yang mengalir melintas celah antara tube dengan temperatur inlet 310 K dan temperatur tubes konstan sebesar 347 K. Dari hasil simulasi ini didapatkan visualisasi kontur kecepatan, temperatur dan visualisasi pola aliran yang terbentuk serta pembuktian hipotesa bahwa dengan penambahan obstacle akan meningkatkan perpindahan panas. Dengan penambahan obstacle dapat mengakibatkan peningkatan pressure drop, sebesar 60-425%. Selain itu, model modified juga akan meningkatkan nilai

  8. Acoustical studies on corrugated tubes

    Science.gov (United States)

    Balaguru, Rajavel

    Corrugated tubes and pipes offer greater global flexibility combined with local rigidity. They are used in numerous engineering applications such as vacuum cleaner hosing, air conditioning systems of aircraft and automobiles, HVAC control systems of heating ducts in buildings, compact heat exchangers, medical equipment and offshore gas and oil transportation flexible riser pipelines. Recently there has been a renewed research interest in analyzing the flow through a corrugated tube to understand the underlying mechanism of so called whistling, although the whistling in such a tube was identified in early twentieth century. The phenomenon of whistling in a corrugated tube is interesting because an airflow through a smooth walled tube of similar dimensions will not generate any whistling tones. Study of whistling in corrugated tubes is important because, it not only causes an undesirable noise problem but also results in flow-acoustic coupling. Such a coupling can cause significant structural vibrations due to flow-acoustic-structure interaction. This interaction would cause flow-induced vibrations that could result in severe damage to mechanical systems having corrugated tubes. In this research work, sound generation (whistling) in corrugated tubes due to airflow is analyzed using experimental as well as Computational Fluid Dynamics-Large Eddy Simulation (CFD-LES) techniques. Sound generation mechanisms resulting in whistling have been investigated. The whistling in terms of frequencies and sound pressure levels for different flow velocities are studied. The analytical and experimental studies are carried out to understand the influence of various parameters of corrugated tubes such as cavity length, cavity width, cavity depth, pitch, Reynolds numbers and number of corrugations. The results indicate that there is a good agreement between theoretically calculated, computationally predicted and experimentally measured whistling frequencies and sound pressure levels

  9. Electronic components, tubes and transistors

    CERN Document Server

    Dummer, G W A

    1965-01-01

    Electronic Components, Tubes and Transistors aims to bridge the gap between the basic measurement theory of resistance, capacitance, and inductance and the practical application of electronic components in equipments. The more practical or usage aspect of electron tubes and semiconductors is given emphasis over theory. The essential characteristics of each main type of component, tube, and transistor are summarized. This book is comprised of six chapters and begins with a discussion on the essential characteristics in terms of the parameters usually required in choosing a resistor, including s

  10. PEG tubes: dealing with complications.

    Science.gov (United States)

    Malhi, Hardip; Thompson, Rosie

    A percutaneous endoscopic gastronomy tube can be used to deliver nutrition, hydration and medicines directly into the patient's stomach. Patients will require a tube if they are unable to swallow safely, putting them at risk of aspiration of food, drink and medicines into their lungs. It is vital that nurses are aware of the complications that may arise when caring for a patient with a PEG tube. It is equally important that nurses know how to deal with these complications or from where tc seek advice. This article provides a quick troubleshooting guide to help nurses deal with complications that can arise with PEG feeding.

  11. Esophageal Atresia: Migration of the gastrostomy tube into the bronchus

    Directory of Open Access Journals (Sweden)

    Hosseini Seyed Mohammad

    2008-01-01

    Full Text Available A 2-day-old baby boy, 38 weeks gestation, weight 2000 g was brought due to hypersalivation and imperforate anus with gasless abdomen on plain X-ray. He underwent a gastrostomy tube insertion and colostomy. In contrast study of the stomach, on the 5th postoperative day, the dye spilled into the tracheo bronchial tree and the catheter was seen,entering the right main bronchus. The patient underwent right thoracotomy and the presence of fistula and catheter were confirmed. The fistula and distal esophagus were closed and fixed to the prevertebral fascia because of a long gap. He is under follow-up and recieving home care for a later delayed primary anastomosis.

  12. Heat transfer enhancement in smooth tube with wire coil insert in laminar and transitional non-newtonian flow

    OpenAIRE

    García Pinar, Alberto; Solano Fernández, Juan Pedro; Viedma Robles, Antonio; Martínez Hernández, David Sebastián

    2010-01-01

    This work presents an experimental study on the heat transfer enhancement by means of a tube with wire-coil insert,for non-Newtonian laminar and transitional flow. The dimensionless pitch and wire diameter (based on the plain tube inner diameter) were chosen as p/D= 1 and e/D=0.09. Two pseudoplastic test fluids have been used: 1% by weight aqueous solutions of carboxymethyl cellulose (CMC) with high viscosity and medium viscosity. A wide range of flow conditions has been covered: Reynolds ...

  13. 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)

  14. Failure probability estimation of flaw in CANDU pressure tube considering the dimensional change

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Sang Log; Kim, Young Jin [Sungkyunkwan Univ., Suwon (Korea, Republic of); Lee, Joon Seong [Kyonggi Univ., Suwon (Korea, Republic of); Park, Youn Won [KINS, Taejon (Korea, Republic of)

    2002-11-01

    The pressure tube is a major component of the CANDU reactor, which supports nuclear fuel bundle and heavy water coolant. Pressure tubes are installed horizontally inside the reactor and only selected samples are periodically examined during in-service inspection. In this respect, a probabilistic safety assessment method is more appropriate for the assessment of overall pressure tube safety. The failure behavior of CANDU pressure tubes, however, is governed by delayed hydride cracking which is the major difference from pipings and reactor pressure vessels. Since the delayed hydride cracking has more widely distributed governing parameters, it is impossible to apply a general PFM methodology directly. In this paper, a PFM methodology for the safety assessment of CANDU pressure tubes is introduced by applying Monte Carlo simulation in determining failure probability. Initial hydrogen concentration, flaw shape and depth, axial and radial crack growth rate and fracture toughness were considered as probabilistic variables. Parametric study has been done under the base of pressure tube dimension and hydride precipitation temperature in calculating failure probability. Unstable fracture and plastic collapse are used for the failure assessment. The estimated failure probability showed about three-order difference with changing dimensions of pressure tube.

  15. Characteristics of Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Li, Zhigang

    and smoke. Air flow through vertical openings has been widely investigated but little is known about the flow in the horizontal openings, especially when they are driven by buoyancy. A literature survey shows that the brine-water system and the scale model are normally used forthe research work of air flow...... through horizontal openings. Two cases of full-scale measurements of buoyancy driven natural ventilation through horizontal openings are performed: one horizontal opening and one horizontal opening combined with one vertical opening. For the case of one horizontal opening, the measurements are made...

  16. The horizontal plane appearances of scoliosis

    DEFF Research Database (Denmark)

    Illés, Tamás S.; Burkus, Máté; Somoskeőy, Szabolcs

    2017-01-01

    Purpose: A posterior-anterior vertebral vector is proposed to facilitate visualization and understanding of scoliosis. The aim of this study was to highlight the interest of using vertebral vectors, especially in the horizontal plane, in clinical practice. Methods: We used an EOS two-/three-dimen......Purpose: A posterior-anterior vertebral vector is proposed to facilitate visualization and understanding of scoliosis. The aim of this study was to highlight the interest of using vertebral vectors, especially in the horizontal plane, in clinical practice. Methods: We used an EOS two...... of scoliosis. The approach used is simple. These results are sufficient for a first visual analysis furnishing significant clinical information in all three anatomical planes. This visualization represents a reasonable compromise between mathematical purity and practical use....

  17. Kinematics of horizontal and vertical caterpillar crawling.

    Science.gov (United States)

    van Griethuijsen, Linnea I; Trimmer, Barry A

    2009-05-01

    Unlike horizontal crawling, vertical crawling involves two counteracting forces: torque rotating the body around its center of mass and gravity resisting forward movement. The influence of these forces on kinematics has been examined in the soft-bodied larval stage of Manduca sexta. We found that crawling and climbing are accomplished using the same movements, with both segment timing and proleg lift indistinguishable in horizontal and vertical locomotion. Minor differences were detected in stride length and in the delay between crawls, which led to a lower crawling speed in the vertical orientation. Although these differences were statistically significant, they were much smaller than the variation in kinematic parameters between animals. The ability of Manduca to crawl and climb using the same movements is best explained by Manduca's relatively small size, slow speed and strong, controlled, passive grip made possible by its proleg/crochets.

  18. Detecting series periodicity with horizontal visibility graphs

    CERN Document Server

    Núñez, Angel M; Valero, Eusebio; Gómez, Jose Patricio; Luque, Bartolo

    2011-01-01

    The horizontal visibility algorithm has been recently introduced as a mapping between time series and networks. The challenge lies in characterizing the structure of time series (and the processes that generated those series) using the powerful tools of graph theory. Recent works have shown that the visibility graphs inherit several degrees of correlations from their associated series, and therefore such graph theoretical characterization is in principle possible. However, both the mathematical grounding of this promising theory and its applications are on its infancy. Following this line, here we address the question of detecting hidden periodicity in series polluted with a certain amount of noise. We first put forward some generic properties of horizontal visibility graphs which allow us to define a (graph theoretical) noise reduction filter. Accordingly, we evaluate its performance for the task of calculating the period of noisy periodic signals, and compare our results with standard time domain (autocorre...

  19. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Li, Zhigang

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... injection tracer gas technique. Smoke visualizations showed that the airflow patterns are highly transient and unstable, and that the airflow rate oscillates with time. Correlations between the Froude (Archimedes) number Fr (Ar) and the L/D ratio are presented. In some cases the measured airflow rates fit...

  20. Horizontal Bilayer for Electrical and Optical Recordings

    Directory of Open Access Journals (Sweden)

    Alf Honigmann

    2012-12-01

    Full Text Available Artificial bilayer containing reconstituted ion channels, transporters and pumps serve as a well-defined model system for electrophysiological investigations of membrane protein structure–function relationship. Appropriately constructed microchips containing horizontally oriented bilayers with easy solution access to both sides provide, in addition, the possibility to investigate these model bilayer membranes and the membrane proteins therein with high resolution fluorescence techniques up to the single-molecule level. Here, we describe a bilayer microchip system in which long-term stable horizontal free-standing and hydrogel-supported bilayers can be formed and demonstrate its prospects particularly for single-molecule fluorescence spectroscopy and high resolution fluorescence microscopy in probing the physicochemical properties like phase behavior of the bilayer-forming lipids, as well as in functional studies of membrane proteins.

  1. Suitable scale of Weigan River plain oasis

    Institute of Scientific and Technical Information of China (English)

    HU ShunJun; SONG YuDong; TIAN ChangYan; LI YueTan; LI XiuCang; CHEN XiaoBing

    2007-01-01

    Desert coexists with oasis in long time, and the existence and development of oasis system demand better oasis vegetation ecological system. Oasis scale of arid zone plain encircling water should be determined in case of desertification caused by land over-reclamation under the circumstance of water resources shortage. Steady oasis with virtuous circle must have appropriate land use structure for agriculture, forestry and graziery. The study on the suitable scale and developmental space of oasis will provide theoretical and applicable foundation for effective construction of oases. By analyzing the hydrothermal, water and soil balance, an optimal mathematical model has been established. Based on hydrometeorology data collected for years in Weigan River plain, and by the principle of water balance,a calculation has been made of the water resources for evapotranspiration and the optimal acreage of oasis and cultivated land, which shows that the water resources for evapotranspiration in the Weigan River plain oasis is 22.32×108 m3 and the optimal oasis acreage under the condition of conventional irrigation mode is 3716.06 km2, in which the suitable cultivated land acreage is 1564.79 km2. Under the condition of water-saving irrigation, the suitable oasis acreage is 5515.49 km2, in which the suitable cultivated land acreage is 2322.31 km2. The oasis area had reached 4123 km2, and the cultivated land acreage had reached 1507 km2 after the Agriculture Irrigation Drainage Water Project of World Bank Loan in Weigan River basin was finished in 1997. The oasis and cultivated land acreage will be more suitable, and the oasis scale can be enlarged moderately by means of water saving irrigation.

  2. Ages of plains volcanism on Mars

    Science.gov (United States)

    Hauber, Ernst; Jagert, Felix; Broz, Petr

    2010-05-01

    Plain-style volcanism [1] is widespread in the Tharsis and Elysium volcanic provinces on Mars, [2,3]. Detailed images and topographic data reveal the morphology and topography of clusters of low shields and associated lava flows. The landforms of plains volcanism on Mars have all well-known terrestrial analogues in basaltic volcanic regions, such as Hawaii, Iceland, and in particular the Snake River Plains [4]. The very gentle flank slopes (Ga - 2.9 Ga). Our results indicate that Late Amazonian volcanism is more widespread in Tharsis than previously recognized. Based on our results it appears possible that Mars is volcanologically not dead yet. Ongoing work investigates the volumes of erupted products and implications for the outgassing history and atmospheric evolution of Mars. [1] Greeley R. (1982) JGR 87, 2705-2712. [2] Plescia J. (1981) Icarus, 45, 586-601. [3] Hodges C.A. and Moore H.J. (1994) Atlas of volcanic features on Mars: USGS Prof. Paper 1534, 194 p. [4] Hauber E. et al. (2009) J. Volcanol. Geotherm. Res. 185, 69-95. [5] Wilson L. et al. (2009) J. Volcanol. Geotherm. Res. 185, 28-46. [6] Vaucher, J. et al. (2009) Icarus 204, 418-442. [7] Baratoux D. et al. (2009) J. Volcanol. Geotherm. Res. 185, 47-68. [8] Bleacher J.E. et al. (2009) J. Volcanol. Geotherm. Res. 185, 96-102. [9] Ivanov B.A. (2001) Space Sci. Rev. 96, 87-104. [10] Hartmann W.H. and Neukum G. (2001) Space Sci. Rev. 96, 165-194 [11] Kneissl T. et al. (2010) LPS XVI, submitted. [12] Michael, G.G. and Neukum G. (2010) Earth Planet. Sci. Lett., in press. . [13] Malin M.C. et al. (2007) JGR 112, E05S04, doi: 10.1029/2006JE002808.

  3. On the propagation mechanism of a detonation wave in a round tube with orifice plates

    Science.gov (United States)

    Ciccarelli, G.; Cross, M.

    2016-09-01

    This study deals with the investigation of the detonation propagation mechanism in a circular tube with orifice plates. Experiments were performed with hydrogen air in a 10-cm-inner-diameter tube with the second half of the tube filled with equally spaced orifice plates. A self-sustained Chapman-Jouguet (CJ) detonation wave was initiated in the smooth first half of the tube and transmitted into the orifice-plate-laden second half of the tube. The details of the propagation were obtained using the soot-foil technique. Two types of foils were used between obstacles, a wall-foil placed on the tube wall, and a flat-foil (sooted on both sides) placed horizontally across the diameter of the tube. When placed after the first orifice plate, the flat foil shows symmetric detonation wave diffraction and failure, while the wall foil shows re-initiation via multiple local hot spots created when the decoupled shock wave interacts with the tube wall. At the end of the tube, where the detonation propagated at an average velocity much lower than the theoretical CJ value, the detonation propagation is much more asymmetric with only a few hot spots on the tube wall leading to local detonation initiation. Consecutive foils also show that the detonation structure changes after each obstacle interaction. For a mixture near the detonation propagation limit, detonation re-initiation occurs at a single wall hot spot producing a patch of small detonation cells. The local overdriven detonation wave is short lived, but is sufficient to keep the global explosion front propagating. Results associated with the effect of orifice plate blockage and spacing on the detonation propagation mechanism are also presented.

  4. Gas reservoir evaluation for underbalanced horizontal drilling

    Directory of Open Access Journals (Sweden)

    Li Gao

    2014-01-01

    Full Text Available A set of surface equipment for monitoring the parameters of fluid and pressure while drilling was developed, and mathematical models for gas reservoir seepage and wellbore two-phase flow were established. Based on drilling operation parameters, well structure and monitored parameters, the wellbore pressure and the gas reservoir permeability could be predicted theoretically for underbalanced horizontal drilling. Based on the monitored gas production along the well depth, the gas reservoir type could be identified.

  5. Horizontal Symmetry: Bottom Up and Top Down

    CERN Document Server

    Lam, C S

    2011-01-01

    A group-theoretical connection between horizontal symmetry $\\G$ and fermion mixing is established, and applied to neutrino mixing. The group-theoretical approach is consistent with a dynamical theory based on $U(1)\\times \\G$, but the dynamical theory can be used to pick out the most stable mixing that purely group-theoretical considerations cannot. A symmetry common to leptons and quarks is also discussed. This higher symmetry picks $A_4$ over $S_4$ to be the preferred symmetry for leptons.

  6. Convection in horizontally shaken granular material

    OpenAIRE

    Saluena, Clara; Poeschel, Thorsten

    1998-01-01

    In horizontally shaken granular material different types of pattern formation have been reported. We want to deal with the convection instability which has been observed in experiments and which recently has been investigated numerically. Using two dimensional molecular dynamics we show that the convection pattern depends crucial on the inelastic properties of the material. The concept of restitution coefficient provides arguments for the change of the behaviour with variing inelasticity.

  7. R&D investments fostering horizontal mergers

    OpenAIRE

    Cabolis, C.; Manasakis, C.; MORENO, Diego; Petrakis, Emmanuel

    2016-01-01

    We study a homogenous good triopoly in which firms first choose their cost-reducing R&D investments and consider alternative merger proposals, and then compete à la Cournot in the ensuing industry. We identify conditions under which both horizontal mergers and non integration are sustained by Coalition-Proof Nash equilibria (CPNE). These conditions involve the effectiveness of the R&D technology, as well as the distribution of the bargaining power between the acquirer and the acquiree, which ...

  8. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... questions Clinical Studies Publications Catalog Photos and Images Spanish Language Information Dilated Exam Grants and Funding Extramural ... Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video ...

  9. Tube-wave seismic imaging

    Science.gov (United States)

    Korneev, Valeri A [LaFayette, CA

    2009-05-05

    The detailed analysis of cross well seismic data for a gas reservoir in Texas revealed two newly detected seismic wave effects, recorded approximately 2000 feet above the reservoir. A tube-wave (150) is initiated in a source well (110) by a source (111), travels in the source well (110), is coupled to a geological feature (140), propagates (151) through the geological feature (140), is coupled back to a tube-wave (152) at a receiver well (120), and is and received by receiver(s) (121) in either the same (110) or a different receiving well (120). The tube-wave has been shown to be extremely sensitive to changes in reservoir characteristics. Tube-waves appear to couple most effectively to reservoirs where the well casing is perforated, allowing direct fluid contact from the interior of a well case to the reservoir.

  10. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... questions Clinical Studies Publications Catalog Photos and Images Spanish Language Information Grants and Funding Extramural Research Division ... Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video ...

  11. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... Grants and Funding Extramural Research Division of Extramural Science Programs Division of Extramural Activities Extramural Contacts NEI ... Amaurosis Low Vision Refractive Errors Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded ...

  12. Pulse tube refrigerator; Parusukan reitoki

    Energy Technology Data Exchange (ETDEWEB)

    Hozumi, Yoshikazu [University of Tsukuba, Tsukuba (Japan); Shiraishi, Masao [Hiroshima University, Hiroshima (Japan)

    1999-06-05

    In the cryogenic field, high temperature superconductivity and research and development of the peripheral technology are popular. Refrigerating machine development of the very low temperature is also one of the results. Research and development are mainly advanced as a refrigerating machine of the center for the aerospace plane installation. There is special and small very low temperature refrigerating machine called 'the pulse tube refrigerating machine' of which the practical application is also recently being attempted for the semiconductor cooling using high temperature superconductivity. At present, the basic research of elucidation of refrigeration phenomenon of pulse tube refrigerating machine and development of high-performance pulse tube refrigerating machine is carried out by experiment in the Ministry of International Trade and Industry Mechanical Engineering Lab., Agency of Industrial Sci. and Technology and numerical simulation in Chiyoda Corp. In this report, the pulse tube refrigerating machine is introduced, and the application in the chemical engineering field is considered. (NEDO)

  13. Lunar Core Drive Tubes Summary

    Data.gov (United States)

    National Aeronautics and Space Administration — Contains a brief summary and high resolution imagery from various lunar rock and core drive tubes collected from the Apollo and Luna missions to the moon.

  14. Medicine Wheels of the Great Plains

    Science.gov (United States)

    Vogt, David

    Medicine Wheels are unexplained aboriginal boulder configurations found primarily on hilltops and river valley vistas across the northwest Great Plains of North America. Their varied, complex designs have inspired diverse hypotheses concerning their meaning and purpose, including astronomical ones. While initial "observatory" speculations were unfounded, and quests to "decode" these structures remain unfulfilled and possibly misguided, the Medicine Wheels nevertheless represent a uniquely worthwhile case study in archaeoastronomical theory and method. In addition, emerging technologies for data acquisition and analysis pertinent to Medicine Wheels offer prospectively important new sight lines for the future of archaeoastronomy.

  15. Thermal transient analysis applied to horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Duong, A.N. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[ConocoPhillips Canada Resources Corp., Calgary, AB (Canada)

    2008-10-15

    Steam assisted gravity drainage (SAGD) is a thermal recovery process used to recover bitumen and heavy oil. This paper presented a newly developed model to estimate cooling time and formation thermal diffusivity by using a thermal transient analysis along the horizontal wellbore under a steam heating process. This radial conduction heating model provides information on the heat influx distribution along a horizontal wellbore or elongated steam chamber, and is therefore important for determining the effectiveness of the heating process in the start-up phase in SAGD. Net heat flux estimation in the target formation during start-up can be difficult to measure because of uncertainties regarding heat loss in the vertical section; steam quality along the horizontal segment; distribution of steam along the wellbore; operational conditions; and additional effects of convection heating. The newly presented model can be considered analogous to pressure transient analysis of a buildup after a constant pressure drawdown. The model is based on an assumption of an infinite-acting system. This paper also proposed a new concept of a heating ring to measure the heat storage in the heated bitumen at the time of testing. Field observations were used to demonstrate how the model can be used to save heat energy, conserve steam and enhance bitumen recovery. 18 refs., 14 figs., 2 appendices.

  16. Vertical and horizontal seismometric observations of tides

    Science.gov (United States)

    Lambotte, S.; Rivera, L.; Hinderer, J.

    2006-01-01

    Tidal signals have been largely studied with gravimeters, strainmeters and tiltmeters, but can also be retrieved from digital records of the output of long-period seismometers, such as STS-1, particularly if they are properly isolated. Horizontal components are often noisier than the vertical ones, due to sensitivity to tilt at long periods. Hence, horizontal components are often disturbed by local effects such as topography, geology and cavity effects, which imply a strain-tilt coupling. We use series of data (duration larger than 1 month) from several permanent broadband seismological stations to examine these disturbances. We search a minimal set of observable signals (tilts, horizontal and vertical displacements, strains, gravity) necessary to reconstruct the seismological record. Such analysis gives a set of coefficients (per component for each studied station), which are stable over years and then can be used systematically to correct data from these disturbances without needing heavy numerical computation. A special attention is devoted to ocean loading for stations close to oceans (e.g. Matsushiro station in Japon (MAJO)), and to pressure correction when barometric data are available. Interesting observations are made for vertical seismometric components; in particular, we found a pressure admittance between pressure and data 10 times larger than for gravimeters for periods larger than 1 day, while this admittance reaches the usual value of -3.5 nm/s 2/mbar for periods below 3 h. This observation may be due to instrumental noise, but the exact mechanism is not yet understood.

  17. Tube wall thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, P.R.

    1987-01-06

    An apparatus is described for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item, the apparatus comprising: a. a base; b. a first support member having first and second ends, the first end being connected to the base, the first support member having a sufficiently small circumference that the tube can be slid over the first support member; c. a spherical element, the spherical element being connected to the second end of the first support member. The spherical element has a sufficiently small circumference at its equator that the tube can be slid over the spherical element, the spherical element having at its equator a larger circumference than the first support member; d. a second support member having first and second ends, the first end being connected to the base, the second support member being spaced apart form the first support member; e. a positioning element connected to and moveable relative to the second support member; and f. an indicator connected to the positioning element and being moveable thereby to a location proximate the spherical element. The indicator includes a contact ball for contacting the selected standard item and holding it against the spherical element, the contact ball contacting the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item, the rotatable needle being operatively connected to and responsive to the position of the contact ball.

  18. Tube wall thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  19. Tube wall thickness measurement apparatus

    Science.gov (United States)

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  20. Tube wall thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, Paul R. (Santa Fe, NM)

    1987-01-01

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  1. Dermatology on YouTube.

    Science.gov (United States)

    Boyers, Lindsay N; Quest, Tyler; Karimkhani, Chante; Connett, Jessica; Dellavalle, Robert P

    2014-06-15

    YouTube, reaches upwards of six billion users on a monthly basis and is a unique source of information distribution and communication. Although the influence of YouTube on personal health decision-making is well established, this study assessed the type of content and viewership on a broad scope of dermatology related content on YouTube. Select terms (i.e. dermatology, sun protection, skin cancer, skin cancer awareness, and skin conditions) were searched on YouTube. Overall, the results included 100 videos with over 47 million viewers. Advocacy was the most prevalent content type at 24% of the total search results. These 100 videos were "shared" a total of 101,173 times and have driven 6,325 subscriptions to distinct YouTube user pages. Of the total videos, 35% were uploaded by or featured an MD/DO/PhD in dermatology or other specialty/field, 2% FNP/PA, 1% RN, and 62% other. As one of the most trafficked global sites on the Internet, YouTube is a valuable resource for dermatologists, physicians in other specialties, and the general public to share their dermatology-related content and gain subscribers. However, challenges of accessing and determining evidence-based data remain an issue.

  2. A laser tube position regulator

    Energy Technology Data Exchange (ETDEWEB)

    Sinyitiro, A.; Norio, K.

    1984-03-26

    An improved design is patented for a mechanism and method of regulating, with a high degree of accuracy, the position of a laser tube in a gas laser inside the optical resonator formed by external mirrors. The laser tube is held in two holders. Each holder contains an L shaped bracket which supports a semitransparent plate. The plate is positioned so that its center is over the center of the end of the tube which is in the form of a Brewster window. A narrow parallel beam is directed along the tube axis from an external auxiliary laser. The beam passes through the semitransparent mirror of the optical resonator in the adjusted laser, through the first Brewster window, the tube itself, and the second Brewster window and is reflected back in the reverse direction from a fully reflecting mirror in the optical resonator. This provides partial reflection of the beam from the external Brewster mirror surface. The tube position in the holders is regulated continuously so that the luminous spots from the beams reflected off the Brewster windows fall on the semitransparent plates in the center of the latter which is designated as the point of intersection.

  3. Horizontal steam generator thermal hydraulic simulation in typical steady and transient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Rabiee, Ataollah, E-mail: rabiee@shirazu.ac.ir; Kamalinia, Amir Hossein; Haddad, Kamal

    2016-08-15

    Highlights: • Simulation of the horizontal steam generator with the available code in typical normal and transient operations. • Replacement of tube bundle with a porous media due to the complexity of the SG geometry. • Simulation of typical transient mode of the VVER 440 steam generator, loss of feed water accident. - Abstract: Thermal hydraulic analysis of the steam generators as one of the main components of the power cycle in pressurized water reactor (PWR) is crucial in the design and safety of the nuclear power plants. Two phase flow field simulation near the tube bundles is important in obtaining logical numerical results however the complexity of the tube bundles due to geometry and arrangement makes the numerical analysis complicated. In this research tube bundle has been assumed as the porous media and the outlet boundary condition as the one of the main challenge in these kind of simulations has been optimized according to similar researches. In order to adjust and tune the available computational fluid dynamic (CFD) code, pressure drop of the typical kettle reboiler tube bundle in two various heat fluxes and vapor volume fraction distribution in VVER 1000 steam generator in normal operation have been investigated. The typical transient mode of the VVER 440 steam generator, loss of feed water accident, has been studied eventually. It was observed that obtained vapor volume fraction can predict experimental data with more accuracy than the similar researches and would be increased with the elevation during the accident. On the other hand, pressure drop and level of the feed water value reduces through time and show good adoption with the measurements.

  4. Paleolimnological reconstruction of Holocene environments in wetland ponds of the Upper Atlantic Coastal Plain

    Energy Technology Data Exchange (ETDEWEB)

    Gaiser, E.E.; Taylor, B.E. [Univ. of Georgia, Athens, GA (United States)

    1995-06-01

    The paleohydrology and paleoecology of Carolina bays and upland wetland ponds on the Savannah River Site (SRS), Aiken, South Carolina are being investigated to reconstruct environmental changes brought about by long-term variation in the climate of the Upper Atlantic Coastal Plain. Cores were taken in transacts through Flamingo Bay, a temporary pond on the SRS, to determine the vertical and horizontal sediment particle size and diatom, plant phytolith and sponge spicule microfossils. Stratigraphic data were used to construct a 3-dimensional map of the basin. In conjunction with archaeological data from the rim of the pond, physical stratigraphic data indicate a decrease in pond size and depth during the past 10,000 years. In order to infer past ecological settings from the fossil record, a survey to determine microhabitat requirements of regional diatom flora was undertaken in 43 temporary ponds throughout the coastal plain of South Carolina. The relationships between diatom assemblages and environmental variables were assessed using canonical correspondence analysis. Variables contributing significantly to the diatom-environment relationship included surface core location (near shore or pelagic), water depth, hydroperiod, microhabitat substrate, and sampling date, in order of decreasing influence. Strong relationships of diatom assemblages to drought frequency within and among basins provides a reliable basis for water level reconstruction in upland temporary ponds.

  5. Improving Web Page Readability by Plain Language

    CERN Document Server

    Hussain, Walayat; Ali, Arif

    2011-01-01

    In today's world anybody who wants to access any information the first choice is to use the web because it is the only source to provide easy and instant access to information. However web readers face many hurdles from web which includes load of web pages, text size, finding related information, spelling and grammar etc. However understanding of web pages written in English language creates great problems for non native readers who have basic knowledge of English. In this paper, we propose a plain language for a local language (Urdu) using English alphabets for web pages in Pakistan. For this purpose we developed two websites, one with a normal English fonts and other in a local language text scheme using English alphabets. We also conducted a questionnaire from 40 different users with a different level of English language fluency in Pakistan to gain the evidence of the practicality of our approach. The result shows that the proposed plain language text scheme using English alphabets improved the reading com...

  6. Plain Language Summary: Adult Sinusitis (Sinus Infection).

    Science.gov (United States)

    Caspersen, Leslie A; Walter, Lindsey M; Walsh, Sandra A; Rosenfeld, Richard M; Piccirillo, Jay F

    2015-08-01

    This plain language summary serves as an overview in explaining sinusitis (pronounced sign-you-side-tis). The purpose of this plain language summary is to provide patients with standard language explaining their condition in an easy-to-read format. This summary applies to those 18 years of age or older with sinusitis. The summary is featured as an FAQ (frequently asked question) format. The summary addresses how to manage and treat sinusitis symptoms. Adult sinusitis is often called a sinus infection. A healthcare provider may refer to a sinus infection as rhinosinusitis (pronounced rhi-no-sign-you-side-tis). This includes the nose as well as the sinuses in the name. A sinus infection is the swelling of the sinuses and nasal cavity.The summary is based on the published 2015 "Clinical Practice Guideline: Adult Sinusitis." The evidence-based guideline includes research to support more effective diagnosis and treatment of adult sinus infections. The guideline was developed as a quality improvement opportunity for managing sinus infections by creating clear recommendations to use in medical practice. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  7. Improving Web Page Readability by Plain Language

    Directory of Open Access Journals (Sweden)

    Walayat Hussain

    2011-05-01

    Full Text Available In todays world anybody who wants to access any information the first choice is to use the web because it is the only source to provide easy and instant access to information. However web readers face many hurdles from web which includes load of web pages, text size, finding related information, spelling and grammar etc. However understanding of web pages written in English language creates great problems for non native readers who have basic knowledge of English. In this paper, we propose a plain language for a local language (Urdu using English alphabets for web pages in Pakistan. For this purpose we developed two websites, one with a normal English fonts and other in a local language text scheme using English alphabets. We also conducted a questionnaire from 40 different users with a different level of English language fluency in Pakistan to gain the evidence of the practicality of our approach. The result shows that the proposed plain language text scheme using English alphabets improved the reading comprehension for non native English speakers in Pakistan.

  8. Genetics Home Reference: horizontal gaze palsy with progressive scoliosis

    Science.gov (United States)

    ... Health Conditions HGPPS horizontal gaze palsy with progressive scoliosis Printable PDF Open All Close All Enable Javascript ... collapse boxes. Description Horizontal gaze palsy with progressive scoliosis ( HGPPS ) is a disorder that affects vision and ...

  9. Creep of plain weave polymer matrix composites

    Science.gov (United States)

    Gupta, Abhishek

    Polymer matrix composites are increasingly used in various industrial sectors to reduce structural weight and improve performance. Woven (also known as textile) composites are one class of polymer matrix composites with increasing market share mostly due to their lightweight, their flexibility to form into desired shape, their mechanical properties and toughness. Due to the viscoelasticity of the polymer matrix, time-dependent degradation in modulus (creep) and strength (creep rupture) are two of the major mechanical properties required by engineers to design a structure reliably when using these materials. Unfortunately, creep and creep rupture of woven composites have received little attention by the research community and thus, there is a dire need to generate additional knowledge and prediction models, given the increasing market share of woven composites in load bearing structural applications. Currently, available creep models are limited in scope and have not been validated for any loading orientation and time period beyond the experimental time window. In this thesis, an analytical creep model, namely the Modified Equivalent Laminate Model (MELM), was developed to predict tensile creep of plain weave composites for any orientation of the load with respect to the orientation of the fill and warp fibers, using creep of unidirectional composites. The ability of the model to predict creep for any orientation of the load is a "first" in this area. The model was validated using an extensive experimental involving the tensile creep of plain weave composites under varying loading orientation and service conditions. Plain weave epoxy (F263)/ carbon fiber (T300) composite, currently used in aerospace applications, was procured as fabrics from Hexcel Corporation. Creep tests were conducted under two loading conditions: on-axis loading (0°) and off-axis loading (45°). Constant load creep, in the temperature range of 80-240°C and stress range of 1-70% UTS of the

  10. Free Piston Double Diaphragm Shock Tube

    OpenAIRE

    OGURA, Eiji; FUNABIKI, Katsushi; SATO, Shunichi; Abe, Takashi; 小倉, 栄二; 船曳, 勝之; 佐藤, 俊逸; 安部, 隆士

    1997-01-01

    A free piston double diaphragm shock tube was newly developed for generation of high Mach number shock wave. Its characteristics was investigated for various operation parameters; such as a strength of the diaphragm at the end of the comparession tube, an initial pressure of low pressure tube, an initial pressure of medium pressure tube and the volume of compression tube. Under the restriction of fixed pressures for the driver high pressure tube (32×10^5Pa) and the low pressure tube (40Pa) in...

  11. Transport Loss Estimation of Fine Particulate Matter in Sampling Tube Based on Numerical Computation

    Science.gov (United States)

    Luo, L.; Cheng, Z.

    2016-12-01

    In-situ measurement of PM2.5 physical and chemical properties is one substantial approach for the mechanism investigation of PM2.5 pollution. Minimizing PM2.5 transport loss in sampling tube is essential for ensuring the accuracy of the measurement result. In order to estimate the integrated PM2.5 transport efficiency in sampling tube and optimize tube designs, the effects of different tube factors (length, bore size and bend number) on the PM2.5 transport were analyzed based on the numerical computation. The results shows that PM2.5 mass concentration transport efficiency of vertical tube with flowrate at 20.0 L·min-1, bore size at 4 mm, length at 1.0 m was 89.6%. However, the transport efficiency will increase to 98.3% when the bore size is increased to 14 mm. PM2.5 mass concentration transport efficiency of horizontal tube with flowrate at 1.0 L·min-1, bore size at 4mm, length at 10.0 m is 86.7%, increased to 99.2% with length at 0.5 m. Low transport efficiency of 85.2% for PM2.5 mass concentration is estimated in bend with flowrate at 20.0 L·min-1, bore size at 4mm, curvature angle at 90o. Laminar flow of air in tube through keeping the ratio of flowrate (L·min-1) and bore size (mm) less than 1.4 is beneficial to decrease the PM2.5 transport loss. For the target of PM2.5 transport efficiency higher than 97%, it is advised to use vertical sampling tubes with length less than 6.0 m for the flowrates of 2.5, 5.0, 10.0 L·min-1 and bore size larger than 12 mm for the flowrates of 16.7 or 20.0 L·min-1. For horizontal sampling tubes, tube length is decided by the ratio of flowrate and bore size. Meanwhile, it is suggested to decrease the amount of the bends in tube of turbulent flow.

  12. 平抛运动演示仪的改进%Improvement of horizontal projectile device

    Institute of Scientific and Technical Information of China (English)

    李燕秋; 代伟; 罗微; 马兰; 黄军

    2015-01-01

    Some improvements were introduced to overcome the shortages of the experiment de‐vice of demonstrating horizontal projectile motion in teaching materials .In horizontal direction ,an e‐lectromagnet was used to make two balls move at the same time .After passing through glass tubes with same bending ,one ball was horizontally projected ,the other was in uniform motion .Finally , two balls would collide with each other .This showed that horizontal projection of horizontal projectile motion is uniform motion .In vertical direction ,a time‐delay circuit was designed using single chip mi‐croprocessor .When the horizontally projected ball and the free‐falling ball landed ,LEDs would emit red light and green light ,respectively ,enabled one to judge if the two balls fell to the ground simulta‐neously ,namely one could judge if a horizontally projected object moves like a free‐falling body in the vertical direction .%针对高中物理教科版教材中平抛运动的演示实验装置存在的不足,对平抛运动演示仪进行了改进。该演示仪在水平方向上,利用电磁铁控制2个小球开始运动时间,当小球通过弯度相同的2个玻璃管后,一个做平抛运动,一个做匀速直线运动,最后会相碰,由此说明平抛运动的在水平方向上是匀速直线运动。在竖直方向上,利用单片机自制了延时电路,当做平抛运动的小球和做自由落体运动的小球落地时,发光二极管会分别发出红光和绿光,通过2个二极管的发光情况可以判断出两小球同时落地,即可以判断出平抛运动的竖直方向上是自由落体运动。

  13. Pump element for a tube pump

    DEFF Research Database (Denmark)

    2011-01-01

    relative to the rod element so as to allow for a fluid flow in the tube through the first valve member, along the rod element, and through the second valve member. The tube comprises an at least partly flexible tube portion between the valve members such that a repeated deformation of the flexible tube...... portion acts to alternately close and open the valve members thereby generating a fluid flow through the tube. The invention further relates to a pump element comprising at least two non-return valve members connected by a rod element, and for insertion in an at least partly flexible tube in such tube...... pump as mentioned above, thereby acting to generate a fluid flow through the tube upon repeated deformation of the tube between the two valve members. The pump element may comprise a connecting part for coupling to another tube and may comprise a sealing part establishing a fluid tight connection...

  14. Study of the Local Horizon. (Spanish Title: Estudio del Horizonte Local.) Estudo do Horizonte Local

    Science.gov (United States)

    Ros, Rosa M.

    2009-12-01

    The study of the horizon is fundamental to easy the first observations of the students at any education center. A simple model, to be developed in each center, allows to easy the study and comprehension of the rudiments of astronomy. The constructed model is presented in turn as a simple equatorial clock, other models (horizontal and vertical) may be constructed starting from it. El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical). O estudo do horizonte é fundamental para facilitar as primeiras observações dos alunos num centro educativo. Um modelo simples, que deve ser feito para cada centro, permite facilitar o estudo e a compreensão dos primeiros rudimentos astronômicos. O modelo construído apresenta-se, por sua vez, como um modelo simples de relógio equatorial e a partir dele pode-se construir outros modelos (horizontal e vertical)

  15. Asymmetric bursting of Taylor bubble in inclined tubes

    Science.gov (United States)

    Rana, Basanta Kumar; Das, Arup Kumar; Das, Prasanta Kumar

    2016-08-01

    In the present study, experiments have been reported to explain the phenomenon of approach and collapse of an asymmetric Taylor bubble at free surface inside an inclined tube. Four different tube inclinations with horizontal (30°, 45°, 60° and 75°) and two different fluids (water and silicon oil) are considered for the experiment. Using high speed imaging, we have investigated the approach, puncture, and subsequent liquid drainage for re-establishment of the free surface. The present study covers all the aspects in the collapse of an asymmetric Taylor bubble through the generation of two films, i.e., a cap film which lies on top of the bubble and an asymmetric annular film along the tube wall. Retraction of the cap film is studied in detail and its velocity has been predicted successfully for different inclinations and fluids. Film drainage formulation considering azimuthal variation is proposed which also describes the experimental observations well. In addition, extrapolation of drainage velocity pattern beyond the experimental observation limit provides insight into the total collapse time of bubbles at different inclinations and fluids.

  16. Horizontal routes: current paths of literary criticism in Latin America

    Directory of Open Access Journals (Sweden)

    Ariadne Costa da Mata

    2013-07-01

    Full Text Available In the last decades, the tendency towards horizontality became visible, particularly (but not only in social movements. Horizontality implies a new architecture in human organizations and pushes for changes in the way knowledge is produced and organized. More than a simple erosion of frontiers between fields, horizontality means the decentralization and dissemination of power.

  17. Application of Horizontal Well Technology to Liaohe Oilfield

    Institute of Scientific and Technical Information of China (English)

    HanYun

    2008-01-01

    @@ Horizontal well technology has become one of the main technologies enabling Liaohe Oilfield to realize stable development. By the end of 2006, 296 horizontal wells of various kinds had been completed in Liaohe Oil Field,273 wells had been put into production, Among uhich 237 were horizontal wells (see Table 1).

  18. YPF uses horizontal reentry to aid thin bed production

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, M.R.; Leiro, F.A.; Sesano, G.S. [Yacimientos Petroliferos Fiscales, La Paz (Bolivia); Hill, D.

    1997-01-01

    Reentry and horizontal drilling/completion techniques have proven themselves useful in exploiting thin beds. A pilot horizontal reentry contracted by Yacimiento Petroliferos Fiscales (YPF) for a marginal well in its Lomita Sur field resulted in decreased water coning and production rates four times greater than expected. Further horizontal reentries in this thin-bed field are planned.

  19. Continuity of subsurface fault structure revealed by gravity anomaly: the eastern boundary fault zone of the Niigata plain, central Japan

    Science.gov (United States)

    Wada, Shigeki; Sawada, Akihiro; Hiramatsu, Yoshihiro; Matsumoto, Nayuta; Okada, Shinsuke; Tanaka, Toshiyuki; Honda, Ryo

    2017-01-01

    We have investigated gravity anomalies around the Niigata plain, which is a sedimentary basin in central Japan bounded by mountains, to examine the continuity of subsurface fault structures of a large fault zone—the eastern boundary fault zone of the Niigata plain (EBFZNP). The features of the Bouguer anomaly and its first horizontal and vertical derivatives clearly illustrate the EBFZNP. The steep first horizontal derivative and the zero isoline of the vertical derivative are clearly recognized along the entire EBFZNP over an area that shows no surface topographic features of an active fault. Two-dimensional density structure analyses also confirm a relationship between the two first derivatives and the subsurface fault structure. Therefore, we conclude that the length of the EBFZNP as an active fault extends to 56 km, which is longer than previously estimated. This length leads to an estimation of a moment magnitude of 7.4 of an expected earthquake from the EBFZNP.[Figure not available: see fulltext.

  20. Demonstration of Eastman Christensen horizontal drilling system -- Integrated Demonstration Site, Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-01

    An innovative horizontal drilling system was used to install two horizontal wells as part of an integrated demonstration project at the Savannah River Site (SRS), Aiken, South Carolina. The SRS is located in south-central South Carolina in the upper Coastal Plain physiographic province. The demonstration site is located near the A/M Area, and is currently known as the Integated Demonstration Site. The Department of Energy`s Office of Technology Development initiated an integrated demonstration of innovative technologies for cleanup of volatile organic compounds (VOCS) in soils and groundwater at the SRS in 1989. The overall goal of the program is to demonstrate, at a single location, multiple technologies in the fields of drilling, characterization, monitoring, and remediation. Innovative technologies are compared to one another and to baseline technologies in terms of technical performance and cost effectiveness. Transfer of successfully demonstrated technologies and systems to DOE environmental restoration organizations, to other government agencies, and to industry is a critical part of the program.