Begell House Inc.
Heat Pipe Science and Technology, An International Journal
HPST
2151-7975
2
1-4
2011
PREFACE
ii-iii
10.1615/HeatPipeScieTech.v2.i1-4.10
Leonard L.
Vasiliev
Porous Media Laboratory Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus 15, Str. P.Brovka, 220072 Minsk, Belarus
Alexander S.
Zhuravlyov
Porous Media Laboratory Luikov Heat and Mass Transfer Institute National Academy of Sciences of Belarus, P. Brovka Str. 15,220072 Minsk, Republic of Belarus
NONINTRUSIVE MEASUREMENT OF THE MASS FLOW RATE INSIDE A CLOSED LOOP TWO-PHASE THERMOSYPHON
1-12
10.1615/HeatPipeScieTech.v2.i1-4.20
Bruno
Agostini
ABB Ltd. Switzerland, Corporate Research, Segelhofstrasse 1K, 5405 Daettwil, Switzerland
Eva
Ferreira
ABB Ltd. Switzerland, Corporate Research, Segelhofstrasse 1K, 5405 Daettwil, Switzerland
two-phase cooling
thermosyphon
bubble velocity
laser
photodiode
Two-phase cooling is a promising technology for electronics cooling. It allows the use of dielectric fluids in passive systems and benefits from high heat transfer coefficients. Thermosyphons are a particularly interesting technology in the field of power electronics being entirely passive and simple equipment. Their performances are strongly related to the flow rate of the fluid inside the thermosyphon. In minichannel thermosyphons liquid entrainment occurs so that flow rate is difficult to evaluate, hence the need for a nonintrusive measurement method. For this purpose a minichannel thermosyphon was manufactured out of borosilicate glass and equipped with a semitransparent indium titanium oxide layer as a direct current heating evaporator. It was illuminated by two lasers through the glass tube and the voltage from two photodiodes placed on the opposite side was measured. With an appropriate signal processing the maximal velocity was determined together with length and frequency of the vapor bubbles, the frequency of the thermosyphon cycle for several filling ratios, and for various heating powers. From these measurements the total mass flow rate, the liquid mass flow rate, the gas mass flow rate, the void fraction, the vapor quality, and the flow cycle frequency were calculated and compared to a thermosyphon simulation model developed at ABB.
EXPERIMENTAL COMPARISON OF THE HEAT TRANSFER PERFORMANCE OF MICROCHANNEL GEOMETRIES
13-26
10.1615/HeatPipeScieTech.v2.i1-4.30
Yigit Ata
Agartan
Mechanical Engineering Department, Middle East Technical University, 06800 Ankara, Turkey
Almila G.
Yazicioglu
Mechanical Engineering Department, Middle East Technical University, 06800 Ankara, Turkey
microchannel
forced convection two-phase heat transfer
refrigerant
R134a
constant wall temperature
In this work, heat transfer for the two-phase refrigerant flow inside three microchannels has been experimentally investigated for use in evaporators of refrigerators. Current literature shows that the low mass flow rates and the constant wall temperature approach common to refrigerator applications is not of general interest in the investigation of flows in microtubes and microchannels. As a result of this observation, first, an experimental setup has been constructed to test the two-phase flow of R134a in three different microchannels in terms of heat transfer performance. For different quality and saturation temperature conditions, the experimental two-phase forced convection heat transfer coefficient of the refrigerant has been determined. Two-phase flow and quality values of the saturated refrigerant have been adjusted with the use of a winding cable preheater. A gear pump has been used to adjust the uniform low mass flow rates. A secondary cycle of water-ethylene glycol mixture has been used to keep the wall temperature of the test section constant. A concentric counter flow heat exchanger has been used in the test section to maintain the heat transfer to the refrigerant. For the three microchannels, the heat transfer coefficient for the refrigerant has been determined for constant mass flux and constant average quality conditions. As a result of data analysis, it has been seen that the seven-port grooved microchannel has the best heat transfer performance.
A TWO-PHASE REVERSE THERMOSYPHON WITH TWO WORK AGENTS
27-29
10.1615/HeatPipeScieTech.v2.i1-4.40
Jurij
Dobrianski
Faculty of Technical Sciences, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 11, 10-736 Olsztyn, Poland
Michal
Duda
Faculty of Technical Sciences, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 11, 10-736 Olsztyn, Poland
Daniel
Chludzinski
Faculty of Technical Sciences, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 11, 10-736 Olsztyn, Poland
reverse thermosyphon
passive heat transfer
two phases
two work agents
A new kind of two-phase reverse thermosyphon with liquid water as a heat carrier and with vapor of refrigerant as a pumping agent will be presented in this paper. The best properties of each work agent are used in this case. In particular, water and its solutions has the best properties as a heat carrier, and refrigerants keep pressure above the atmospheric pressure inside of devices if the temperature lies in the range from 0 to 100°C. It considerably improves the operating characteristics of the device and allows elimination of the mechanical transporting pump out of the loop with circulation directed opposite the natural convection. The main news consists of adding a second work agent and performing heat carrying and pumping of the heat carrier with the help of two different work agents. A few copies of the two-phase reverse thermosyphon loop with two work agents were successfully tested under laboratory conditions and in combination with an experimental solar installation.
USE OF HEAT PIPES FOR ELECTRONICS BLOCK THERMOSTATING OF MAGNETIC MEASUREMENT SYSTEM FIXED ON SPACE VEHICLE
31-41
10.1615/HeatPipeScieTech.v2.i1-4.50
S. A.
Grishin
The B. I. Stepanov Institute of Physics, 68 Prospekt Nezavisimosti, Minsk BY-220072, Republic of Belarus
Aliaksei L.
Petsiuk
B.I. Stepanov Institute of Physics, National Academy of Sciences, Minsk, Belarus
S. S.
Grishin
The B. I. Stepanov Institute of Physics, 68 Prospekt Nezavisimosti, Minsk BY-220072, Republic of Belarus
V. V.
Doctorov
The Powder Metallurgy Institute, 41 Platonov St., Minsk BY-220005, Republic of Belarus
Victar V.
Maziuk
Powder Metallurgy Institute, Platonov str., 41, 220005, Minsk, Belarus
heat pipe
heat sink
thermostating system for onboard equipment
magnetic measurement system
numerical modeling of thermal processes
The paper examines the use of heat pipes in magnetic measurement system designed for installation on the spacecraft to monitor the state of Earth's magnetic field and the magnetic environment near the modules and blocks of spectrometric equipment complex. A numerical simulation is made in order to select type of heat pipe and determine optimum design parameters of the elements of the heat sink. Installation on the basis of chamber for heat and a cold for carrying out thermal tests of onboard equipment is described. The automated multisensor network system of temperature measurement is considered. The results of thermal testing of the electronics magnetic measurement system are discussed. The expediency in heat pipes for thermostating blocks of onboard scientific equipment is shown.
PERFORMANCE OF GEOTHERMAL THERMOSYPHON USING PROPANE
43-53
10.1615/HeatPipeScieTech.v2.i1-4.60
Thomas
Grab
TU Bergakademie Freiberg, Gustav-Zeuner-Strasse 7, 09599 Freiberg, Germany
Thomas
Storch
Institute of Thermal Engineering, TU Bergakademie Freiberg, Gustav-Zeuner-Strasse 7, 09599
Freiberg, Germany
Ulrich
Gross
Institute of Thermal Engineering, TU Bergakademie Freiberg, Gustav-Zeuner-Str. 7, 09599 Freiberg,
Germany
Steffen
Wagner
Institute of Drilling Technology and Fluid Mining, Technische Universitat Bergakademie Freiberg, 09596 Freiberg, Germany
geothermal thermosyphon
two phase closed thermosyphon
propane
cooling and heating
geothermal energy
phase change
Approximately 46% of the household heat pumps installed in 2011 in Germany are combined with geothermal heat exchangers [3]. Geothermal heat can be extracted by standard heat exchangers such as U-tubes or coaxial tubes, through which a fluid is circulated. A more effective way to extract geothermal heat is through using the thermosyphon principle where a fluid with a low boiling temperature (e.g., propane) is circulated through the heat exchanger. A combination of both types of heat exchangers can be very effective for heating and cooling as the heat is stored in the ground and helps the underground temperature to regenerate much faster. At the energy park of the TU Bergakademie Freiberg in Germany, a heat pump system based on geothermal thermosyphons combined with geothermal brine tubes is currently under evaluation. The present work is focused on the operating performance of this heating and cooling system. The experimental plant is equipped with various measuring devices including a fiber-optical sensor attached on the outside of the tubes. The present paper reports the effect of various operating parameters on the temperature profiles along the tubes combined with pressure and temperature measurements at the heat pump system, and finally its power consumption. The amount of extracted and introduced energy per day will be presented, leading to conclusions for an effective operating regime. The operation of geothermal thermosyphons proved to be effective; there is however some need for further optimization, for example the evaluation of measured data shows that film spreading cannot be expected along the whole inner tube surface.
REGULATING CHARACTERISTICS OF THERMAL CONTROL SYSTEMS ON THE BASIS OF VARIABLE CONDUCTANCE HEAT PIPES AT VARIABLE HEAT GENERATION AND EXTERNAL HEAT EXCHANGE CONDITIONS
55-67
10.1615/HeatPipeScieTech.v2.i1-4.70
Volodymyr M.
Baturkin
Heat Pipe Laboratory, National Technical University of Ukraine "Kyiv Polytechnic Institute", 37 Peremogy Ave., Kiev, 03056, Ukraine; Institute of Space Systems, 7 Robert-Hooke Str., Bremen, 28359, Germany
thermal control systems
heat pipe
heat transfer models
heat exchange research
testing
application
scientific devices
space research
The paper is devoted to decision of the scientific-applied problem of creation of the high-efficiency thermal control systems (TCS) of scientific space apparatus, operating in nonhermetical compartments, with the use of heat pipes of variable conductance (VCHP), executing the functions of transport of heat and control of the temperature of devices by maintenance of thermal balance in the system "mounting place of device in a spacecraft (SC)−device−space environment" on the required temperature level. Heat balance equations are the basis for definition of thermal parameters of TCS elements: heat pipe, radiator, thermal insulation, flexible elements, low conductance supports, cables, contact resistances, providing function of passive TCS. Proposed conceptions of TCS do not foresee subsidiary electric power consumption of spacecraft, and they are based on the use of inherent heat generation of scientific devices, or the heat of subsidiary sources such as the sun, providing stabilization of device temperature at the level of 290 K. Such approach is experimentally tested for the groups of scientific devices: for separate electronic cards (with mass of 0.3 kg), autonomous electronic unit (mass to 5 kg), and device panel of SC compartment (mass, 60 kg) at the change of inherent heat generation ration 1:10, temperatures of SC 253−323 K, and illumination by external sources (sun, planet) to 270 W/m2.
EXPERIMENTAL STUDY OF THE EFFECTS OF VIBRATION AND HORIZONTAL ANGLE ON THE DYNAMICS OF STARTUP AND TRANSIENT REGIMES OF THE HEAT PIPE
69-78
10.1615/HeatPipeScieTech.v2.i1-4.80
V. I.
Lutsenko
Department of Mechanics of Machines and Processes of Processing Mineral Raw Materials, The Polyakov Institute of Geotechnical Mechanics, of National Academy of Science of Ukraine, Simferopolskaya, 2, Dnipropetrovsk, 49005, Ukraine
V. I.
Eliseyev
Department of Mechanics of Machines and Processes of Processing Mineral Raw Materials, The Polyakov Institute of Geotechnical Mechanics, of National Academy of Science of Ukraine, Simferopolskaya, 2, Dnipropetrovsk, 49005, Ukraine
heat pipe
start-up
transition mode
temperature
vibration
experiment
heating
cooling
Heat pipes with metal-fibrous capillary structure were studied. The studied frequency range was 10−4000 Hz, the vibration level from 0 to 100 m/s°. Free rotation of the pipe at any angle with respect to the horizontal was provided. Ten thermocouples on the outer surface of the pipe in the heating zone, and three thermocouples on the outer surface of the cooling zone were established. Portholes of glass at the ends of the heat pipe were made. The data of the start-up of the heat pipe are provided. The effect of vibration and tilt angles of the heat pipe on its parameters are shown. It was determined that the slope of the heat pipe α = +30° is optimal. Vibration increases the temperature gradient. It was established that the dynamic properties of the cooling system with heat pipe are determined by external boundary conditions. Heat pipe responds quickly to changes in external boundary conditions, and its thermal resistance varies widely.
INVESTIGATION OF THE GUIDE INSERTIONS INFLUENCE ON THE CONDENSATION OF WATER IN A NARROW GAP CONDENSER OF A LOOP HEAT PIPE
79-87
10.1615/HeatPipeScieTech.v2.i1-4.90
E.
Bartuli
Institute of Thermal Physics, Ural Branch of the Russian Academy of Sciences, Amundsena St., 107a, Yekaterinburg, 620016, Russia
M.
Chernysheva
Institute of Thermal Physics, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, 620016, Russia
S.
Vershinin
Institute of Thermal Physics, Ural Branch of the Russian Academy of Sciences, 106 Amundsen St., Ekaterinburg 620016, Russia
Yury F.
Maydanik
Institute of Thermal Physics, Ural Branch of the Russian Academy of Sciences, 107a Amundsen Str., Yekaterinburg, 620016, Russia
loop heat pipe
gap condenser
condensation
heat transfer
thermal resistance
This paper presents the results of an investigation of heat transfer and hydrodynamics during the condensation of water vapor in a narrow gap condenser of a loop heat pipe. The length of the condenser was 80 mm. The cross section measured 40 × 1.1 mm. Instrumental investigations and visual observations of the condensation process in the condenser with and without longitudinal guide insertions were carried out. The investigations were conducted at a condenser cooling temperature from 60 to 95° C. During all operating parameters a stratified two-phase flow and film condensation were observed. The temperature field in the condenser and the heat-transfer coefficients were measured. The heat-transfer coefficients in the condenser without the insertions were in the range from 21 to 46 kW/(K·m2), with the insertions from 42 to 88 kW/(K·m2).
FULLSCALE THERMAL VACUUM TESTS OF BELARUSIAN SPACECRAF
89-99
10.1615/HeatPipeScieTech.v2.i1-4.100
A.
Gutkin
Institute of Electromechanics, 11, Panfilova St., Istra, Moscow region, 143500, Russia
A.
Chobitko
Institute of Electromechanics, 11, Panfilova St., Istra, Moscow region, 143500, Russia
Konstantin
Goncharov
Federal State Unitary Enterprise "Scientific Production Association named after S. A. Lavochkin", 24 Leningradskoe Highway, Khimki, Moscow region, Russia
A.
Kochetkov
The Heat Pipe Centre, Lavochkin Association, 24, Leningradskaya St., Khimki, Moscow region, 141400, Russia
K.
Dorofeev
The Heat Pipe Centre, Lavochkin Association, 24, Leningradskaya St., Khimki, Moscow region, 141400, Russia
A. I.
Shnip
A. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, Minsk, Belarus
spacecraft
vacuum test
heat pipes
thermal control
The thermal control system (TCS) of the Belarusian spacecraft is developed on the basis of axial grooved heat pipes (AGHPs). The TCS includes thermal honeycomb panels with embedded AGHPs in them with outer diameter of 12.5 mm (Fig. 1), the angular AGHPs with outer diameter of 8 mm
(Fig. 2), and "-shaped" AGHPs with outer diameter of 12.5 mm (Fig. 2). Angular AGHPs divert the heat from the honeycomb panels toward the body radiator of the spacecraft. The four collector "-shaped" HPs bind honeycomb panels together for leveling temperature distribution. The thermal vacuum comprehensive tests (TVT) of the spacecraft are the most important and responsible stage during the land thermal vacuum adjustment. Carrying out the TVTs in land conditions is one of the major factors providing spacecraft normal functioning in regular operation conditions. The following was carried out during the tests: the TCS functionality check similar to the real operational conditions; construction temperature fields were investigated; the TCS efficiency on different thermal
loadings was determined; and the onboard equipment was checked with the help of the telemetry data received by the measuring and computing complex. The necessary TCS improvements can be made and the admission of the spacecraft to the flight tests can be received by the results of TVTs. The TCS efficiency tests were made by means of the unit temperature change in the course of tests.
IMPROVEMENT OF OPERATION EFFECTIVENESS OF A CLOSED GEOTHERMAL HEAT EXCHANGER DUE TO IMPLEMENTATION OF ACTIVE INSULATION OF THE EXTRACTION ELEMENT
101-113
10.1615/HeatPipeScieTech.v2.i1-4.110
Radomir
Kaczmarek
Department of Heat Engineering, West-Pomeranian University of Technology al. Piastow 17, PL 70-310 Szczecin, Poland
Wladyslaw
Nowak
Department of Heat Engineering, West-Pomeranian University of Technology al. Piastow 17, PL 70-310 Szczecin, Poland
Aleksander A.
Stachel
Department of Heat Engineering, West-Pomeranian University of Technology al. Piastow 17, PL 70-310 Szczecin, Poland
geothermal energy
utilization of geothermal energy
underground closed geothermal heat exchanger
active insulation
active insulation of the extraction
element
The idea of construction of the so-called underground closed geothermal heat exchanger presents an interesting concept of energy extraction from the resources contained in the Earth's crust. Such exchanger consists of a system of pipelines founded at a significant depth through which liquid is pumped, extracting energy from surrounding rocks and transporting heat to the Earth's surface.
From the accomplished analyses, it results that the least efficient element from the efficiency point of view is the vertical part of such heat exchanger. As a result, significant reduction of temperature of the energy carrier fluid at the outflow is observed, leading to reduction of the overall efficiency of the heat exchanger. Bearing in mind that application of the passive insulation in the extraction part of the exchanger is technically difficult, the authors proposed the concept of the active insulation. The idea is based on the formation in the extraction part of two concentrically positioned channels, namely the
inner circular channel, through which the principal flow rate of fluid flows and the external annular channel, where part of liquid flows serving as insulation layer. In the paper, we briefly present the calculation model with the active insulation enabling determination of the influence of the liquid flow rate in the external insulation channel on temperature distribution of the basic flow rate of the heat carrier flowing in the inner channel. That enabled conduction of the assessment of the influence of application of the active insulation on the improvement of the efficiency of operation of the entire
geothermal heat exchanger.
RESEARCH AND DEVELOPMENT ON PERFORMANCES OF LARGE-SIZED THERMOELECTRIC MODULE WITH HEAT PIPES
115-120
10.1615/HeatPipeScieTech.v2.i1-4.120
L.
Anatychuk
Institute of Thermoelectricity, 9-A Dubinskaja str., Chernovci, 58000, Ukraine
L.
Vikhor
Institute of Thermoelectricity, 9-A Dubinskaja str., Chernovci, 58000, Ukraine
Yu.
Rozver
Institute of Thermoelectricity, 9-A Dubinskaja str., Chernovci, 58000, Ukraine
Boris
Rassamakin
Heat Pipes Laboratory, Heat and Power Department, National Technical University of Ukraine "KPI", 709, 6 Politekhnichna Str, Kiev, 03056, Ukraine
Sergey
Khairnasov
Heat Pipes Laboratory, Heat and Power Department, National Technical University of Ukraine "KPI", 709, 6 Politekhnichna Str, Kiev, 03056, Ukraine
Yu.
Nikolaienko
Thermal Power Department, National Technical University of Ukraine “Kyiv Polytechnic Institute”, 6 Politechnichna str., room 311, Kyiv, 03056, Ukraine
heat pipe
thermoelectric module
Experimental development results of a large-size thermoelectric cooling module with heat pipes,
which is capable of providing a thermal stabilization of electronic components of heightened power, are presented. The application of such assemblies of large-size modules and flat heat pipes allows us to meet the challenges of heat removal under increased heat flows and space limitedness for conventional heat-removing heat sinks placement. The construction and manufacturing technique of modules are optimized. Parameter analysis and characteristics of modules with heat pipes in different modes and heat removal conditions are performed. It is shown that it is reasonable to reduce heat pipe thermal
resistance to the level of 0.05 K/W for the purpose of cooling efficiency increase.
TWO-PHASE SYSTEMS FOR LIGHT-EMITTING DIODES COOLING
121-131
10.1615/HeatPipeScieTech.v2.i1-4.130
Valery M.
Kiseev
Ural Federal University, Department of Thermophysics and Surface Phenomena, Lenin av. 51, 620083, Ekaterinburg, Russia
Dmitry S.
Aminev
Ural Federal University, Department of Thermophysics and Surface Phenomena, Lenin av. 51, 620083, Ekaterinburg, Russia
Victor G.
Cherkashin
Ural Federal University, Department of Thermophysics and Surface Phenomena, Lenin av. 51, 620083, Ekaterinburg, Russia
two-phase thermal control system
conventional thermosyphon
loop thermosyphon
heat pipe
LED lamp
radiator
working fluid
heat transfer
Extensive development of the light-emitting diode (LED) devices on the basis of LED matrix offers capabilities for LED to occupy an increasingly important place for street and industrial lighting as more reliable and energy-efficient. However, there are not enough experimental data on the optimization of the cooling systems for LED devices. Traditionally, the cooling systems for LED devices are designed with even pitch of LED locations on the radiator's surface. By the increase of LED power
the radiator's surface and the distance between the LED locations grows correspondingly. It results
in the increase of the mass and size of the LED device. This paper presents some designs of twophase
thermal control systems for the LED cooling on the basis of conventional thermosyphon, loop
thermosyphon, and heat pipe and studies the experimental data, which were investigated for the twophase
systems considering the gravity influence. The presented results include: some designs of the two-phase systems for the LED cooling; start-up characteristics under low, high, and intermediate powers; power cycling (monotonic and random) and sink temperature cycling behavior; and temperature drop and temperature oscillations during startup and working regime.
PROGRAM TOOLKIT FOR MODELING AND OPTIMIZATION OF ADSORPTION AND CHEMICAL HEAT PUMPS AND REFRIGERATORS
133-143
10.1615/HeatPipeScieTech.v2.i1-4.140
M.
Liakh
A.V. Luikov Heat and Mass Transfer Institute, NAS of Belarus, 15 P. Brovka St., Minsk, 220072, Republic of Belarus
O. S.
Rabinovich
A. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, Minsk, Belarus
adsorption
chemical reaction
heat pump
refrigerator
modeling
A set of programs for numerical modeling and optimization of adsorption and chemical heat pumps and refrigerators has been developed. The modeling is based on one-dimensional (in the radial direction) consideration of dynamic adsorption or chemical reversible reactions in a cylindrical reactor filled with adsorbent. The program toolkit allows investigation of various heat-conversion devices designed as a combination of one or several reactors with condensers and evaporators. The programs
have options for varying reactor parameters, thermal reservoir temperatures, resistance of control
valves connecting the reactors, as well as time of their opening and closing. The graphical representation
of time history for mean temperature and sorbate content in the reactors is shown in the program window as well as the effective Clausius–Clapeyron-diagram dynamics of working medium. As a result of modeling, the programs calculate main characteristics of thermal energy conversion such as coefficient of perfomance (COP), specific cool (and heat) production, SHP (SCP), and the maximal temperature difference between the heat carrier and adsorbent during the process. The developed
approach and algorithms were validated by comparison of numerical results with experimental data.
AUTONOMOUS THERMOSIPHON SYSTEM FOR WWER 1000 COOLDOWN
145-159
10.1615/HeatPipeScieTech.v2.i1-4.150
Igor
Sviridenko
Sevastopol State University, Sevastopol, Russia
Dmitriy V.
Shevielov
Sevastopol Branch of Scientific and Technical Support Separate Subdivision "Scientific and Technical Center" of State Enterprise National Nuclear Energy Generating Company "Energoatom", Sevastopol, Ukraine
reactor
cooldown
passive residual heat removal system
two-phase thermosiphon
pressurizer
The article presents application of an autonomous passive residual heat removal system (RHRS) for cooldown of nuclear power plants (NPP) with water-cooled, water-moderated power reactors (WWER 1000). The residual heat is removed via heat exchangers composed of two-phase thermosiphons. The proposed system also provides efficient primary de-pressurization by natural circulation of steam
from pressurizer's upper part through emergency gas removal system towards thermosiphon heat exchanger
and eventual return of the condensate back to the primary circuit. The results of analytical modeling show, that the suggested passive system provides for timely injection of boric acid solution from hydro accumulators (HAs) and thus sufficient subcriticality margins during the entire reactor
installation cooldown process simultaneously maintaining subcooled conditions in the reactor core.
The results of analytical modeling of emergency cooldown of the reactor installation during complete, long-term blackout event are presented. It is proved that proposed passive heat removal system provides efficient heat sink and primary de-pressurization. That creates conditions for actuation of emergency core cooling system (ECCS) HAs and maintains adequate subcriticality during the transient
along with maintaining subcooled conditions of the primary coolant in the reactor core.
VISUALIZATION OF A LOOP HEAT PIPE USING NEUTRON RADIOGRAPHY
161-172
10.1615/HeatPipeScieTech.v2.i1-4.160
Atsushi
Okamoto
Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba, Ibaraki, 305-8505, Japan
Ryuta
Hatakenaka
Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba, Ibaraki, 305-8505, Japan
Masahide
Murakami
University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8571, Japan
loop heat pipe
neutron radiography
visualization
thermal control
heat transfer
space
It has recently become difficult to meet the increasing thermal control requirement of spacecraft with
existing thermal control devices. A loop heat pipe (LHP) is an effective method to satisfy the requirement.
JAXA has been developing a small LHP for space application. As part of the development and
to better understand LHP operation, visualization of the working fluid using neutron radiography
was conducted. As a result, much significant information, such as the behavior of the liquid at startup
and dryout behavior in the primary wick, was observed. This information contributes greatly to
the improvement of LHP design and the establishment of a numerical simulation model.
THERMALLY POWERED ADSORPTION CYCLES: THE QUEST FOR SUSTAINABLE COOLING
173-184
10.1615/HeatPipeScieTech.v2.i1-4.170
Bidyut Baran
Saha
International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University
744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; Kyushu University Program for Leading Graduate School, Green Asia Education Center
Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen 6-1
Kasuga-shi, Fukuoka 816-8580, Japan; Mechanical Engineering Department, Kyushu University
744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
Ibrahim I.
El-Sharkawy
International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; Mechanical Power Engineering Department, Faculty of Engineering, Mansoura University, El-Mansoura 35516, Egypt; Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen 6-1, Kasuga-shi, Fukuoka 816-8580, Japan
activated carbon
adsorption
cooling
ethanol
thermally powered
The severities of energy crisis and environmental problems have been calling for rapid developments
in thermally powered adsorption systems using natural and/or alternative to hydrofluorocarbonbased
refrigerants. Adsorption isotherms, kinetics, and heat of adsorption data of adsorbent–
refrigerant pairs are essential for designing adsorption cooling and heat pump systems. This paper
presents the adsorption kinetics of ethanol onto a highly porous activated carbon fiber along with a
brief overview of thermally activated adsorption cooling cycles. System outlines, theory of operation,
and characteristics of multibed, multistage cycles are presented for cooling applications.