Experimental Study on Start-up Performance of Closed Loop Pulsating Heat Pipe

The start-up performance of closed-loop pulsating heat pipe(CLPHP) with ethanol as the working fluid under different working conditions was experimentally investigated.The influence of liquid filled ratio,inclination angle and heat load on start-up performance were analyzed.Two types of the start-up process were observed: the start-up with apparent temperature overshoot and the start-up with smooth temperature increasing.The results indicate that the optimal range of liquid filled ratio for start-up performance is from 41% to 52%.The start-up performance is improved with the increase of inclination angle from 0° to 90° under the same heat load.Moreover,with the increase of heat load,the start-up time decreases while the maximum start-up temperature increases.