Experimental Study of a Nitrogen Loop Heat Pipe for Cooling Large Area Heat Source

A cryogenic loop heat pipe (CLHP) is an efficient two-phase heat transfer device. It works without mechanical moving parts, external power, vibrations and electromagnetic interference. Hence, the CLHP can isolate optics and detectors from mechanical vibrations and improve image quality of large Far Infrared space telescopes. In this experiment, the working fluid was nitrogen and the operating temperature range was 80–120K. The method of supercritical startup was by applying capillary pump with power. In this paper, the effects of different capillary pump powers on supercritical startup characteristics, relationship between charge pressure and heat transfer limit were studied. In the end, the responsiveness and temperature stability with heat load changing cyclically were investigated. The CLHP could achieve successful startup under auxiliary heat load of 2W and got a heat transport capacity of 3W.