A two phase fluid loop system with multiple coldplates in parallel

A two phase fluid loop system for space use has been experimentally studied. Results on its coldplates, both on a single coldplate and on two coldplates in parallel lines, are presented in this paper. The coldplate, consisting of 19 grooved double-pipes and designed for 2.5 kW heat load, showed its evaporative heat transfer coefficient to be nearly 10 times as large as liquid single phase flow when coolant exit quality was between 0.5 and 0.8. In the case of two identical coldplate operation, each coldplate behaved in the same manner as a single coldplate until flow oscillation started to occur. The oscillation, in which flow rate to each coldplate oscillated with the total flow rate remaining almost constant, significantly decreased the cooling capability of the coldplate, and showed hysteretic characteristics once it initiated. It was also found out that the oscillation was able to be prevented by flow resistance at the coldplate inlet.