Investigation of Heat Transfer in Evaporator of Microchannel Loop Heat Pipe

Loop heat pipes (LHP) are closed loop heat transfer devices which use evaporation and condensation of a working fluid to transfer heat and use capillary forces to provide fluid circulation. One of the main applications of LHP is cooling of electronics components. Further development in this field is associated with miniaturization. Therefore in electronics cooling there are strict limits imposed upon size of elements of heat transfer devices. One of such elements is evaporator of LHP, its main element. This paper deals with LHP evaporator and aims to find ways of reducing its thickness. An open loop experimental setup was created to investigate heat transfer phenomena in evaporator. Experiments were carried out with variety of configurations. Evaporator consists of microchannel plates with groove width 100 and 300 micrometers, wick (metal and non-metal porous materials were used) and compensation chamber (CC). Heat load varied from 20 to 140 W by steps of 20 W. The area of heater was equal to 19 mm × 19 mm. Working fluid — deionised water. Experiments resulted in data on temperature distribution across wick’s height, temperature of microchannel’s surface and temperature of water in compensation chamber. The results reveal potentials to perform optimization of evaporating zone to produce thinner evaporators.