Thermal performance of separated flat loop heat pipe
In the field of FLHP(flat loop heat pipe),the main obstacle to the heat transfer performance is the heat leakage from evaporator to compensation chamber.To decrease such heat leakage and meet the needs of electronics cooling,a FLHP with separated evaporator and compensation chamber was designed,and a low-conductivity polytetrafluoroethylene was adopted as the primary capillary wick in the evaporator.The shells and the lines were made of stainless steel,and ammonia was used as working fluid.The results show that the FLHP is insensitive to the gravity.To be specific,under the anti-gravity,gravity-assisted and horizontal attitude,the FLHP starts up quickly with low heat load of 2 W(0.29 W/cm2).In each of the three cases,the thermal resistances are all lower thian 0.06 ℃/W at the maximum transfer heat load of 90 W.Compared with the conventional FLHP,the new-proposed FLHP with separated structure is with lower start-up heat load,higher heat transfer limit and wider application range.Under moderate heat load(40-60 W)and anti-gravity attitude,a phenomenon of sudden temperature drop associated with increasing heat load in the evaporator is reported and rationally explained by the transformation in condensation flow pattern.
万方数据
维普
