ABSTRACT

The effect of electron beam irradiation on the performance of an oscillating heat pipe (OHP), resulting from the transformation or decomposition of the working fluid 1,1,1,2-tetrafluoroethane (HFC-134a), was studied for a next-generation cubic micro-satellite composed of OHP panels. The OHP, containing 70 wt.% HFC-134a, was irradiated with 100 krad gamma rays. The OHP operated normally as a fixed-conductance OHP. There was little difference in the thermal conductance and maximum heat transfer rate before and after irradiation. The composition of the HFC-134a working fluid was analyzed by chromatography after irradiation to determine the impurities. The composition of the irradiated fluid was compared with that of the non-irradiated fluid, and four hydrochlorofluorocarbons (HCFCs) assumed to be decomposition products were detected at levels of several parts per million. Therefore, OHP performance was not degraded by 100 krad radiation.