Experimental Study on a Flat Loop Heat Pipe Coupling the Compensation Chamber and the Condenser

Abstract

Loop heat pipes are high efficient heat transfer loops/devices. Compared to the typical loop heat pipe with cylinder evaporator, loop heat pipe with flat evaporator (flat loop heat pipe, FLHP) can reduce the thermal resistance between the evaporator and the heat loads. In order to remove the heat leak from the evaporator to the compensation chamber to reduce the operation temperature, a new type of FLHP coupling the compensation chamber and the condenser has been developed. Experiments have been conducted to compare the heat transfer characteristics between the normal type and the new type of FLHP. Part of the heat lead from the evaporator to the compensation chamber can be removed in the new type of FLHP, so it gives better heat transfer performance than the normal one. Results show that, the temperatures in the loop of the new type of FLHP are much more stable than the normal one. The evaporator temperatures and the total thermal resistances of the new type are much lower than those of the normal type. For the normal type of FLHP, it may be failed to start up under low power, and usually the larger temperature oscillation will happen. With the power increasing, the frequency of the oscillation is increasing. When the applied power is large enough, the loop can keep running in the design way, and the large temperature oscillation will disappear.