Experimental Study of Non-Symmetry Micro Channel Flat Plate Pulsating Heat Pipe Under Variable Conditions

In order to solve the problem of efficient heat dissipation of miniaturized electronic devices and the difficulty of horizontal operation of pulsating heat pipe, this study designed a non-symmetry micro-channel flat plate pulsating heat pipe (NCPHP) and built an experimental platform for its heat transfer performance. By controlling different incline angles, filling rate and cooling water temperature, the operation characteristics of NCPHP were investigated under the structure design of non-symmetry channel. The results show that the thermal resistance of NCPHP is sensitive to the change of incline angle at 30% and 50% filling rate, and the dry-out phenomenon of NCPHP is observed at 30% filling rate. At 50% filling rate, the thermal resistance of NCPHP can be as low as 0.622 and 0.545 K/W when incline angle is −5° and 0°, respectively. The minimum thermal resistance of NCPHP was 0.415 K/W when the incline angle is 60° and the filling rate is 50%. When the incline angle is −5° and the liquid filling rate is 50%, and the heating power reaches 40 W, the temperature in the evaporation section of NCPHP continues to rise in a short time, but this phenomenon disappears and changes into a stable and fluctuating characteristic when the heating power reaches 50 W. The influence of cooling water temperature on the average temperature difference in the evaporation section of NCPHP decreases with the increase of heating power. At 50% liquid filling rate, the temperature difference of NCPHP evaporation section decreases from 5.1 ℃ at 30 W to 4.2 ℃ at 60 W. Lower cooling water temperature can delay the dry-out phenomenon of 30% liquid filling rate.