I-60 Influence of admixtures of the compressor oil to the enthalpy of working fluid in evaporator [Текст] / V. P. Zhelezny, P. V. Zhelezny, P. V. Skripov, V. F. Vozniy, D. A. Procenko, S. N. Ancherbak // Compressors 2004, International Conference on Compressors and Coolants, 5th, Casta Papiernicka, Slovakia, Sept. 29-Oct. 1, 2004. - 2004. - С. 303-309 Рубрики: ФИЗИКА Кл.слова (ненормированные): ADMIXTURES |
I-70 Investigation of startup behaviors of a loop-heat pipe / H. X. Zhang, G. P. Lin, T. Ding, Yu. F. Maydanik, R. G. Sudakov // Journal of Termophysics and Heat Transfer. - 2005. - Vol. 19, № 4. - С. 509-518 Рубрики: ФИЗИКА Кл.слова (ненормированные): HEAT PIPES -- VAPOR/LIQUID DISTRIBUTION -- VAPOR GROOVES Аннотация: The results of ground experiments on startup behaviors of a loop heat pipe are presented. One objective is to investigate the effects of working conditions on the startup of loop heat pipes. Startup behaviors as functions of various parameters, including the vapor/liquid distribution-in the evaporator, startup heat load, sink temperature, and adverse elevation are described and explained. The physical process of startup is described, and the explanation that pressure transfer leads to the saturated temperature rise in the compensation chamber during startup is discussed. The other objective is to investigate the effect of startup on the steady-state operation of loop heat pipes. Test results indicate that evaporation inside the wick tends to occur at low startup heat loads when the evaporator, including the vapor grooves and the evaporator core, is flooded with liquid. Some peculiar phenomena, including evaporation inside the wick, temperature oscillation at the condenser inlet, and reverse flow equilibrium, which lead to higher operating temperatures, were observed during startups |
E 97 Experimental study on start-up characteristics of loop heat pipes / H. X. Zhang, G. P. Lin, T. Ding, R. G. Sudakov, Yu. F. Maydanik // Scienein China Series E-Engineering & Materials Science. - 2005. - Vol. 48, № 2. - С. 131-144 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPE -- START-UP -- EXPERIMENT Аннотация: This paper presents results of ground-experimental study on the start-up characteristics of a Loop Heat Pipe. The physical process of start-up is described, and the explanation that "Pressure Transfer" leads to the saturated temperature rise in compensation chamber during start-up is first discussed. Start-up behaviors as a function of various parameters including vapor/liquid distribution in the evaporator, adverse elevation, start-up heat load, sink temperature are described and explained. A peculiar start-up phenomenon composed of two start-up scenarios was first observed at adverse elevations and is described |
H 65 High heat flux loop heat pipes / M. T. North, D. B. Sarraf, J. H. Rosenfeld, Yu. F. Maydanik, S. V. Vershinin // 6th European Symposium on Space Environmental Control Systems: Noordwijk, Netherlands, 20-22 may 1997 . - 1997. - Vol. 400. - С. 371-376 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPES -- POWER LOADS -- GRAVITATIONAL HEADS Аннотация: Loop Heat Pipes (LHPs) can transport very large thermal power loads, over long distances, through flexible, small diameter tubes and gravitational heads. While recent transported as much as 1500 W, the peak heat flux through a LHP's evaporator has been limited to about 0.07 MW/m(2). This limitation is due to the arrangement of vapor passages next to the heat load which is one of the conditions necessary to ensure self priming of the device. This paper describes work aimed at raising this limit by threefold to tenfold. Two approaches were pursued. One optimized the vapor passage geometry for the high heat flux conditions. The geometry improved the heat flow into the wick and working fluid. This approach also employed a finer pored wick to support higher vapor flow losses. The second approach used a bidisperse wick material within the circumferential vapor passages. The bidisperse material increased the thermal conductivity and the evaporative surface area in the region of highest heat flux, while providing a flow path for the vapor. Proof-of-concept devices were fabricated and tested for each approach. Both devices operated as designed and both demonstrated operation at a heat flux of 0.70 MW/m(2) This performance exceeded the known state of the art by a factor of more than six for both conventional heat pipes and for loop heat pipes using ammonia. In addition, the bidisperse-wick device demonstrated boiling heat transfer coefficients up to 100,000 W/m(2).K, and the fine pored device demonstrated an orientation independence with its performance essentially unaffected by whether its evaporator was positioned above, below or level with the condenser |
P 31 Pastukhov, V. G. Adaptation of loop heat pipes to zero-g conditions / V. G. Pastukhov, Yu. F. Maydanik, Y. G. Fershtater // 6th European Symposium on Space Environmental Control Systems: Noordwijk, Netherlands, 20-22 may 1997 . - 1997. - Vol.400. - С. 385-391 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPES -- HEAT-TRANSPORT -- THERMOCAPILLARY PHENOMENA Аннотация: Loop heat pipes (LHPs) posses a great variety of valuable properties, which make them quite promising for application both on the Earth and in space. Among these are the LHP high heat-transport capacity at an any orientation in the field of mass forces, good mass-and-size parameters and the possibility of an arbitrary configuration of transport lines. At the same time such a drawback of LHPs of the conventional type as the instability of start up and operation in the region of low heat loads reduces their performance. The problem is connected, in a general case, with the unfavourable distribution of the vapor and the liquid phases of the working fluid in the evaporator. There is reason to believe that the LHP operation can also be significantly affected by zero-g conditions, in which the distribution of a working fluid is pre-determined only by the action of surface forces and the thermocapillary phenomena. The paper performs a general analysis of the necessary conditions imposed on the construction of LHP and some designs that contribute to the retention of serviceability in zero-g conditions at low heat loads. It gives the results of laboratory investigations of an adapted ammonia LHP with a heat-transfer capacity up to 2 kWxm |
T 44 The proof-of-feasibility of multiple evaporator loop heat pipes / W. B. Bienert, D. A. Wolf, M. N. Nikitkin, Yu. F. Maydanik, Y. G. Fershtater, S. V. Vershinin, J. M. Gottschlich // 6th European Symposium on Space Environmental Control Systems: Noordwijk, Netherlands, 20-22 may 1997 . - 1997. - Vol.400. - С. 393-398 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPES -- THERMAL CONTROL -- MULTIPLE THERMAL INTERFACE Аннотация: This paper presents results that demonstrate the proof-of-feasibility of multiple evaporator Loop Heat Pipes (LHP). It was demonstrated that a multiple evaporator LHP can successfully operate as a thermal control system component. A breadboard LHP with multiple evaporators (two) that retained the reliable self starting behavior of the single thermal interface LHP was developed. Program efforts were concentrated on a two pump system and investigated the performance of the dual evaporator LHP. Analytical predictons and experimental test data are compared, and important issues are discussed that will be a baseline for continued development of multiple thermal interface LHPs. All of the conclusions are based on test results, analytic modeling and the correlation of the two. Although a mathematical model that predicts the multiple evaporator LHP behavior was developed, the primary focus of the program was the development, fabrication, and test of a breadboard multi-evaporator LHP. The program clearly demonstrated that multi-evaporator LHPs are feasible and merit further development as a viable thermal control components |
H 65 High heat flux loop heat pipes / M. T. North, D. B. Sarraf, J. H. Rosenfeld, Yu. F. Maydanik, S. V. Vershinin // SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM (STAIF-97), PTS 1-3: 1ST CONFERENCE ON FUTURE SCIENCE & EARTH SCIENCE MISSIONS; 1ST CONFERENCE ON SYNERGISTIC POWER & PROPULSION SYSTEMS TECHNOLOGY; 1ST CONFERENCE ON APPLICATIONS OF THERMOPHYSICS IN MICROGRAVITY; 2ND CONFERENCE ON COMMERCIAL DEVELOPMENT OF SPACE; - 2ND CONFERENCE ON NEXT GENERATION LAUNCH SYSTEMS; 14TH SYMPOSIUM ON SPACE NUCLEAR POWER AND PROPULSION, ALBUQUERQUE, 26-30 JAN, 1997 . - 1997. - Vol.387. - С. 561-566 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPES -- THERMAL POWER LOADS -- VAPOR FLOW LOSSES Аннотация: Loop Heat Pipes (LHPs) can transport very large thermal power loads, over long distances, through flexible, small diameter tubes and against high gravitational heads. While recent LHPs have transported as much as 1500 W, the peak heat flux through a LHP's evaporator has been limited to about 0.07 MW/m(2). This limitation is due to the arrangement of vapor passages next to the heat load which is one of the conditions necessary to ensure self priming of the device. This paper describes work aimed at raising this limit by threefold to tenfold. Two approaches were pursued. One optimized the vapor passage geometry for the high heat flux conditions. The geometry improved the heat flow into the wick and working fluid. This approach also employed a finer pored wick to support higher vapor flow losses. The second approach used a bidisperse wick material within the circumferential vapor passages. The bidisperse material increased the thermal conductivity and the evaporative surface area in the region of highest heat flux, while providing a flow path for the vapor. Proof-of-concept devices were fabricated and tested for each approach. Both devices operated as designed and both demonstrated operation at a heat flux of 0.70 MW/m(2). This performance exceeded the known state of the art by a factor of more than six for both conventional heat pipes and for loop heat pipes using ammonia. In addition, the bidisperse-wick device demonstrated boiling heat transfer coefficients up to 100,000 W/m(2) K, and the fine pored device demonstrated an orientation independence with its performance essentially unaffected by whether its evaporator was positioned above, below or level with the condenser |
P 31 Pastukhov, V. G. Development and investigation of a cooler for electronics on the basis of two-phase loop thermosyphons / V. G. Pastukhov, Yu. F. Maydanik, V. I. Dmitrin // Heat Pipe Science and Technology, An International Journal , vol. - Vol.1, №1. - С. 47-57 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP THERMOSYPHON -- EVAPORATOR -- CAPILLARY STRUCTURE, Аннотация: The objective of this work was to develop a device for cooling electronic elements with a heat power up to 30 W by its rejection and dissipation in the ambient by free air convection. The device specification assigned the temperature range of the ambient conditions from −40 to +105° C and the available space of 30(W) × 120(H) × 200(L) mm. As a result a hybrid scheme based on a loop thermosyphon was proposed, where the evaporator embodied the capillary structure. In such a scheme, the return working fluid flow was ensured by the combined action of the gravity and capillary forces. Several prototypes with different loop and evaporator designs were tested in laboratory conditions. Water and heptane were used as working fluids. The experiments showed that the role of the capillary structure locally placed in the evaporator can be efficiently implemented by both highly porous cellular materials and capillary grooves made on the evaporating surface. It is also shown that heptane can be effectively used as a working fluid which is appropriate for the temperature range requirements. At the same time the device has good mass-and-size characteristics and total thermal resistance under a nominal heat load of about 1.7° C/W |
S 82 Steady state operation of a copper–water LHP with a flat-oval evaporator / S. Becker, S. V. Vershinin, V. Sartre, E. Laurien, J. Bonjour, Yu. F. Maydanik // Applied Thermal Engineering. - 2011. - Vol.31, №5. - С. 686-695. - Библиогр.: с. 695 (24 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPE -- HEAT TRAHSFER -- EXPERIMENTAL STUDY Аннотация: In order to dissipate the heat generated by electronic boxes in avionic systems, a copper–water LHP with a flat-oval evaporator was fabricated and tested at steady state. The LHP consists of a flat shaped evaporator, 7 mm thick, including compensation chamber with attached heat exchanger. The condenser is cooled by forced convection of liquid. The variable parameters are the heat sink and ambient temperatures (20 and 55 °C), the orientation (−90° to +90° in two perpendicular planes) and the power input (0–100 W). Evaporator wall temperatures are higher when the evaporator is placed above the condenser. For heat sink and ambient temperature of 20 °C the evaporator wall temperature does not vary much with heat load for all measured elevations. But it fluctuates at heat sink and ambient temperature equal to 55 °C when the evaporator is placed below the condenser. The LHP total thermal resistance is governed by the condenser resistance. It decreases with increasing heat load, whatever the operating conditions, because the part of the condenser internal surface area used for condensation increases too. A minimum thermal resistance of 0.2 K/W was obtained. The maximum thermal resistance was 2.7 K/W \\\\expert2\\NBO\\Applied Thermal Engineering\\2011, v. 31, p.686.pdf |
I-70 Investigation of a compact copper–water loop heap pipe with a flat evaporator / Yu. F. Maydanik, S. V. Vershinin, M. Chernysheva, S. Yushakova // Applied Thermal Engineering. - 2011. - Vol.31, №16. - С. 3533-3541. - Библиогр.: с. 3541 (22 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): ELECTRONICS COOLING -- LOOP HEAT PIPE -- FLAT–OVAL EVAPORATOR Аннотация: A compact copper–water loop heat pipe (LHP) with an effective length of 310 mm equipped with a flat–oval evaporator measuring 80 (L) × 42 (W) × 7 (H) has been tested. The vapor line and the condenser had the same internal diameter of 5.4 mm. The internal diameter of the liquid line was 3.4 mm. Tests were conducted with a heat source which had a heating surface of 30 mm × 30 mm. The condenser was cooled by running water with a temperature of 20 °C. In the horizontal position the device has exhibited serviceability in the heat load range from 5 W to 1200 W at vapor temperatures from 26.5 °C to 103.4 °C. The maximum capacity was achieved at a heat source temperature of 143.5 °C, when the LHP thermal resistance was equal to 0.044 °C/W. The corresponding values of thermal resistance for the evaporator and the condenser were at a level of 0.006 °C/W and 0.038 °C/W. A minimum thermal resistance of 0.097 °C/W for the “heat source–LHP–cooling water” system was obtained at a heat load of about 700 W, at which the temperature of the heat source was 87 °C \\\\expert2\\NBO\\Applied Thermal Engineering\\2011, v. 31, p.3533.pdf |
M 19 Maydanik, Yu. F. Development and Tests of Miniature Loop Heat Pipe with a Flat Evaporator / Yu. F. Maydanik, S. V. Vershinin, M. A. Chenysheva // SAE 2000 Transaction - Journal of Aerospace. - 2001. - Paper Number: 2000-01-2491 Рубрики: ФИЗИКА Кл.слова (ненормированные): AMMONIA MINIATURE -- LOOP HEAT PIPE -- FLAT EVAPORATOR Аннотация: The paper presents the results of analysis, development and tests of an ammonia miniature loop heat pipe (MLHP) with a flat evaporator, which has an active-zone diameter of 30mm. The length and the diameter of the vapor and the liquid lines are 1m and 2/1.2mm. The device serviceability has been demonstrated at a horizontal and a vertical orientation in 1-g conditions. The maximum heat load achieved on trials was equal, respectively, to 160W and 120W, which corresponds to a heat flow in the evaporation zone of 23 W/cm 2 and 17 W/cm 2 . The minimum thermal resistance at nominal heat loads from 40 to 80 W varied in the range from 0.42 W/m 2 K to 0.59 W/m 2 K. A comparison has been made with a model MLHP with a cylindrical evaporator equipped with a copper and aluminum “sa |
S 82 Steady-state and transient performance of a miniature loop heat pipe / Chen. Yuming, M. Groll, R. Mertz, Yu. F. Maydanik // International Journal of Thermal Science. - 2006. - Vol.45. - С. 1084-1090 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPES -- HEAT TRAHSFER -- ELECTRONICS COOLING Аннотация: A series of tests have been carried out with a miniature loop heat pipe (mLHP), which has been developed for consumer electronics cooling, for horizontal and four vertical orientations under different sink temperatures. The mLHP has a cylindrical evaporator of 5 mm outer diameter and 29 mm length. The steady-state operating characteristics are similar for different orientations except for the orientation where the evaporator is above the compensation chamber. At an evaporator temperature of 75 °C, an evaporator heat load up to 70 W can be reached with thermal resistance of about 0.2 °C/W. The transient behavior of the mLHP is studied in detail. In general, the mLHP can be started up with very low power input (5 W). Big temperature oscillations in the liquid line were found in many cases, however, the temperature oscillations in the evaporator are minimum. The orientations greatly influence the operating characteristics of the mLHP. At least for the horizontal orientation, the overall performance of the tested mLHP is satisfying |
C 51 Chernysheva, M. A. Numerical simulation of transient heat and mass transfer in a cylindrical evaporator of a loop heat pipe / M. A. Chernysheva, Yu. F. Maydanik // International Journal of Heat and Mass Transfer. - 2008. - Vol.51, №17-18. - С. 4204-4215 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPE -- LHP START-UP -- BOILING-UP Аннотация: The paper investigates the transient processes of heat and mass transfer in a cylindrical evaporator of a loop heat pipe (LHP) during the device start-up. One of the most “arduous” prestart situations, which is characterized by the absence of a liquid in the evaporator central core and filled vapor removal channels, has been considered. With such liquid distribution a successful start-up of an LHP becomes possible only after formation of the vapor phase in the vapor removal channels and their liberation from the liquid. The aim of the investigations is to determine conditions that ensure the boiling-up of a working fluid in vapor removal channels. The problem was solved by a numerical method. Simulation of start-up regimes has been performed for different heat loads and different structural materials of the evaporator. Copper, titanium and nickel wick have been examined. Calculations have been made for three different working fluids; water, ammonia and acetone. Account has been taken of the conditions of heat exchange between the compensation chamber and surrounding medium |
M 43 Maydanik, Yu. F. Development and tests of ammonia Miniature Loop Heat Pipes with cylindrical evaporators / Yu. F. Maydanik, S. V. Vershinin // Applied Thermal Engineering. - 2009. - Vol.29, №11-12. - С. 2297-2301 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPE -- EVAPORATOR -- CONDENSER Аннотация: Miniature Loop Heat Pipes (MLHPs) are an attractive object for development and investigation as quite a promising means for cooling powerful electronics operating in the temperature range from 50 to 100 °C. The paper generalizes and presents the results of development and tests of 15 different variants of ammonia MLHPs with cylindrical evaporators 5 and 6 mm in diameter, which have an active zone length of 20 mm and are equipped with titanium and nickel wicks. As a result of successive efforts aimed at increasing the MLHPs efficiency, it was possible to achieve values of the heat-transfer coefficient close to 162,000 W/m2 °C at a value of the heat flux of about 100 × 104 W/m2. A maximum heat flux value of about 135 × 104 W/m2 was achieved at the heat-transfer coefficient equal approximately to 75,000 W/m2 °C |
Heat and Mass Transfer in Evaporator of Loop Heat Pipe // Journal of Termophysics and Heat Transfer. - 2009. - Vol.23, №4. - С. 725-731 Кл.слова (ненормированные): HEAT-EXCHANGE -- EVAPORATOR -- LOOP HEAT PIPE Аннотация: Investigation of heat-exchange processes in the evaporator of a loop heat pipe is important for the development of heat transfer devices with low thermal resistances. A two-dimensional mathematical model of the evaporator active zone is presented. Three modes of vapor generation in the wick have been examined, where each differs in the mechanism of the vapor phase formation and in the saturation of the capillary structure: 1) evaporation to the vapor grooves, 2) volumetric evaporation in the two-phase zone, and 3) volumetric evaporation in the two-phase zone separated from the heated wall of the evaporator by dried zones. Conditions identifying changes between modes have been formulated. Structural characteristics of the wick with different pore sizes have been taken into account. Using a numericalanalytical method, results were obtained for three copper loop heat pipes with biporous wicks, where the working fluid was water for one of the loop heat pipes and methanol for the other two. The heat-load dependent temperature drop between the evaporator wall and the vapor in the vapor grooves has been presented. Additionally, a comparative analysis of calculated and experimental results was performed |
C 51 Chernysheva, M. A. Analysis of heat exchange in the compensation chamber of a loop heat pipe [Электронный ресурс] / M. A. Chernysheva, V. G. Pastukhov, Yu. F. Maydanik // Energy . - 2013. - Article in Press Рубрики: ФИЗИКА Кл.слова (ненормированные): COMPENSATION CHAMBER -- FLAT EVAPORATOR -- HEAT-AND-MASS TRANSFER -- LOOP HEAT PIPES Аннотация: A three-dimensional heat-and-mass transfer model of a flat evaporator of a loop heat pipe has been developed for investigating heat-and-mass in a compensation chamber filled with a liquid. Numerical simulation was implemented using EFDLab® software package in order to predict the temperature distribution of the flat evaporator of a copper-water LHP (loop heat pipe) as well as the flow streamline and velocity field in the compensation chamber as a function of heat load. A computer simulation makes it possible to evaluate the heat exchange at the inner surface of the compensation chamber. Heat exchange data were used as a boundary condition in researching the problem of the drying effect of a wick and a transformation of the evaporating front in the active zone of the flat evaporator. © 2013 Elsevier Ltd. All rights reserved |
C 51 Chenysheva, M. A. Simulation of thermal processes in a flat evaporator of a copper-water loop heat pipe under uniform and concentrated heating [Электронный ресурс] / M. A. Chenysheva, Yu. F. Maydanik // International Journal of Heat and Mass Transfer. - 2012. - Vol.55, № 25-26. - P7385-7397 Рубрики: ФИЗИКА Кл.слова (ненормированные): 3D MODEL -- EVAPORATION -- FLAT EVAPORATOR Аннотация: A 3D model has been developed for investigating heat and mass transfer in a flat evaporator of a copper-water loop heat pipe. It takes into account heat-transfer processes in the active zone, the barrier layer of the wick, the wall and the compensation chamber. The problem was solved by the finite difference method with the use of a nonuniform grid adapted to the configuration of the flat evaporator and its geometric peculiarities. Investigations have been carried out for understanding the effect of the heating zone size on heat distribution in the evaporator. The heating area was 9 cm 2 with a uniform heat supply and 1 cm 2 with a concentrated one. Numerical simulation has been performed for a heat load range from 20 to 1100 W. Data have shown that a decrease in the heating area at a fixed heat load results in both increasing temperature on the evaporator wall under the heater and local wick draining in the active zone. The results of the model have been verified using results of experimental tests. |
C 51 Chernysheva, M. A. 3D-model for heat and mass transfer simulation in flat evaporator of copper-water loop heat pipe [Electronic resource] / M. A. Chernysheva, Yu. F. Maydanik // Applied Thermal Engineering. - 2012. - Vol.33-34, №1. - P124-134 Рубрики: ФИЗИКА Кл.слова (ненормированные): EVAPORATION -- FLAT EVAPORATOR -- MATHEMATICAL MODEL Аннотация: This paper presents a three-dimension mathematical model of a flat evaporator of a loop heat pipe which takes into account the peculiarities of the evaporator configuration and the specific character of a one-side heat load supply. All the main structural elements of the evaporator, such as its body, wick, vapor-removal grooves, barrier layer and compensation chamber, are included in the model. The intensity of heat-exchange processes during evaporation in the active zone is determined by local drops between the temperature at the wick surface and the vapor temperature. The effects of drying the wick in the evaporation zone are also taken into account. The problem was solved by a numerical method. The results of calculations are presented for a copper evaporator and water as a working fluid in the heat load range from 20 to 1100 W. A comparative analysis of calculated and experimental data has been made \\\\expert2\\NBO\\Applied Thermal Engineering\\2012, v. 33-34, p.124.pdf |
P 31 Pastukhov, V. G. Combined LHP and PHP based heat-transfer system / V. G. Pastukhov, Yu. F. Maydanik // International Journal of Thermal Science. - 2013. - Vol.74. - С. 81-85 Рубрики: ФИЗИКА Кл.слова (ненормированные): HEAT-TRANSFER SYSTEM -- LOOP HEAT PIPE -- PULSATING HEAT PIPE Аннотация: The paper presents the results of development and experimental investigation of a heat-transfer system consisting of a pulsating and a loop heat pipe. The pulsating heat pipe (PHP) was made of a copper capillary tube 2 mm in diameter and located on an aluminum plate measuring 260 × 200 × 1 mm, had a thermal contact with the evaporator interface of a loop heat pipe (LHP) 0.6 m long. The working fluid of the PHP was R141b. The LHP was filled with ammonia. A heat-load source measuring 200 × 200 mm was located on the PHP, and its heat was transferred to the LHP evaporator. Tests were conducted at different orientations in the gravity field at heat loads from 10 to 170 W and heat-sink temperatures from −20 to +20 °C. A minimum value of thermal resistance equal to 0.28 °C/W was achieved in the heat load range from 50 to 90 W. |
C 51 Chernysheva, M. A. Copper-water loop heat pipes for energy-efficient cooling systems of supercomputers / M. A. Chernysheva, S. Yushakova, Yu. F. Maydanik // Energy . - 2014. - С. 534-542. - Bibliogr. : p. 542 (16 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): COOLING SYSTEM -- OPERATING TEMPERATURE -- LOOP HEAT PIPE Аннотация: An implementation of a cooling system with a loop heat pipe for thermal control of supercomputers is considered. For this purpose two copper-water loop heat pipes (LHPs) with an effective length of 400mm and ID/OD diameters of the vapor lines of 3/4 and 4/5mm correspondingly were designed and tested. The LHPs were equipped with a flat-oval evaporator with one-sided heat supply. The evaporator had a thickness of 7mm, a length (including the compensation chamber) of 80mm and a width of 42mm. The influence of the cooling temperature of the condenser on the LHP operating characteristics was the central issue of this research. Tests were conducted in the range of the cooling temperature from 20 to 80°C. The heat load supplied to the evaporator was varied from 20 to 600W. A mathematical model for prediction of the LHP's operating temperature has been developed. It takes into consideration three operating modes of a loop heat pipe. Modeling results and their analysis are presented \\\\expert2\\nbo\\Energy\\2014, v. 69, p. 534-542.pdf |