An Experimental Investigation of Miniature Loop Heat Pipe with Flat Evaporator

This paper specifically addresses the thermal characteristics of the miniature loop heat pipe (mLHP) with flat disk shaped evaporator for the thermal control of the compact electronic devices. The loop was made of stainless steel with sintered nickel wick and ammonia as the working fluid. Detail study was conducted on the start-up reliability of the mLHP and the operating characteristics under different heat loads. In the horizontal orientation, the device was able to transfer maximum heat-flux of 7W/cm2 with evaporator temperature below 55degC limit. The experiments conformed that the mLHP could achieve steady state in very short time and adapt the different heat-flux loads very well. The effect of the sink temperature was studied in detail, and decrease of the sink temperature was useful to the start-up of the mLHP but useless to decrease the temperature of the evaporator wall.