Experimental Study on Start-up Forms and Temperature Oscillation of Loop Heat Pipe Enhanced by Pressure Head of Evaporation

The start-up forms and temperature oscillation of loop heat pipe enhanced by pressure head of evaporation was studied in this paper. In this LHP, the wick was separated from the heating surface and then a steam chamber was formed, in which the pressure head of evaporation could be effectively used. Three start-up forms, the steady start-up form, the overshoot start-up form, and the dropping-evaporation start-up form, were observed for different heat loads and charging ratios. The steady start-up form occurred when the heat load was low and the temperature oscillation was obvious; the overshoot start-up form occurred when the heat load was 220 W, in which there was no obvious temperature oscillation; and the dropping-evaporation form occurred when the charging ratio decreased. Moreover, the amplitude and period of temperature oscillation showed a decreased tendency with the increase of the heat load. © 2020, Science Press. All right reserved.