Study on heat transfer characteristics of reservoir embedded loop heat pipe (1st report, Influence of evaporator orientation against gravity and charged liquid weight on heat transfer characteristics)

2007 ◽  
Vol 36 (3) ◽  
pp. 143-157
Author(s):  
Hiroaki Ishikawa ◽  
Tetsuro Ogushi ◽  
Takehide Nomura ◽  
Takeshi Iwakami ◽  
Hiroyuki Noda ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Loop Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

scholarly journals Heat-Transfer Characteristics of a Cryogenic Loop Heat Pipe for Space Applications

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1616
Author(s):  
Jaehwan Lee ◽  
Dongmin Kim ◽  
Jeongmin Mun ◽  
Seokho Kim
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Infrared Detectors ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Zero Gravity ◽  
Heat Transfer Characteristics ◽  
Space Applications ◽  
Transfer Characteristics ◽  
Start Up

Infrared detectors on satellites and spacecraft require cooling to increase their measurement sensitivity. To efficiently cool infrared detectors in a zero gravity environment and in limited spaces, a cryogenic loop heat pipe (CLHP) can be used to transfer heat over a certain distance by the capillary forces generated from porous wicks without a mechanical power source. The CLHP presented in this study transfers the heat load to a condenser 0.5 m away from an evaporator at temperatures below −150 °C. The CLHP with two evaporators includes a subloop for initial start-up, and uses a pressure reduction reservoir (PRR) for the supercritical start-up from room to cryogenic temperature. Nitrogen is used as the working fluid to verify the thermal behavior of the CLHP, and the heat-transfer capacity according to the nitrogen charging pressure of the PRR is investigated. To simulate a cryogenic environment, the CLHP is installed inside a space environment simulator, including a single-stage GM (Gifford McMahon) cryocooler to cool the condenser. The CLHP is horizontally installed to simulate zero gravity. The heat-transfer characteristics are experimentally evaluated through the loop circulation of the CLHP.

Effect of Wick Characteristics on the Thermal Performance of the Miniature Loop Heat Pipe

2009 ◽  
Vol 131 (8) ◽  
Author(s):  
Randeep Singh ◽  
Aliakbar Akbarzadeh ◽  
Masataka Mochizuki
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Working Fluid ◽  
Vapor Flow ◽  
Loop Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Two phase heat transfer devices based on the miniature version of loop heat pipe (LHP) can provide very promising cooling solutions for the compact electronic devices due to their high heat flux management capability and long distance heat transfer with minimal temperature losses. This paper discusses the effect of the wick properties on the heat transfer characteristics of the miniature LHP. The miniature model of the LHP with disk-shaped evaporator, 10 mm thick and 30 mm disk diameter, was designed using copper containment vessel and water as the working fluid, which is the most acceptable combination in electronic cooling applications. In the investigation, wick structures with different physical properties including thermal conductivity, pore radius, porosity, and permeability and with different structural topology including monoporous or biporous evaporating face were used. It was experimentally observed that copper wicks are able to provide superior thermal performance than nickel wicks, particularly for low to moderate heat loads due to their low heat conducting resistance. With monoporous copper wick, maximum evaporator heat transfer coefficient (hev) of 26,270 W/m2 K and evaporator thermal resistance (Rev) of 0.06–0.10°C/W were achieved. For monoporous nickel wick, the corresponding values were 20,700 W/m2 K for hev and 0.08–0.21°C/W for Rev. Capillary structure with smaller pore size, high porosity, and high permeability showed better heat transfer characteristics due to sufficient capillary pumping capability, low heat leaks from evaporator to compensation chamber and larger surface area to volume ratio for heat exchange. In addition to this, biporous copper wick structure showed much higher heat transfer coefficient of 83,787 W/m2 K than monoporous copper wick due to improved evaporative heat transfer at wick wall interface and separated liquid and vapor flow pores. The present work was able to classify the importance of the wick properties in the improvement of the thermal characteristics for miniature loop heat pipes.

Heat transfer characteristics of a reservoir embedded loop heat pipe (2nd report, Influence of noncondensable gas on heat transfer characteristics)

2007 ◽  
Vol 36 (8) ◽  
pp. 459-473 ◽  
Author(s):  
Hiroaki Ishikawa ◽  
Tetsuro Ogushi ◽  
Takehide Nomura ◽  
Hiroyuki Noda ◽  
Haruo Kawasaki ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Loop Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Noncondensable Gas ◽  
Transfer Characteristics

Study on heat transfer characteristics of reservoir embedded loop heat pipe (Influence of condenser cooling method on heat transfer characteristics)

2009 ◽  
Vol 38 (2) ◽  
pp. 118-133 ◽  
Author(s):  
Hiroaki Ishikawa ◽  
Takehide Nomura ◽  
Tetsuro Ogushi ◽  
Hiroyuki Noda ◽  
Haruo Kawasaki ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Loop Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Cooling Method

scholarly journals G060042 Study on Heat Transfer Characteristics of Loop Heat Pipe for Solar Collector

2012 ◽  
Vol 2012 (0) ◽  
pp. _G060042-1-_G060042-3
Author(s):  
Shota SATO ◽  
Shigeki HIRASAWA ◽  
Tsuyoshi KAWANAMI ◽  
Katsuaki SHIRAI
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Solar Collector ◽  
Loop Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics
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