A Robust Two-Phase Pumped Loop with Multiple Evaporators and Multiple Radiators for Spacecraft Applications

NASA’s future remote sensing science missions will require advanced two-phase pumped loop systems to enable precise thermal control of multiple advanced instruments and electronics, and effectively utilize waste heat to keep propellant to stay above its minimal allowable temperature. To meet this need, Creare is developing an innovative two-phase pumped loop with multiple evaporators and multiple radiators. The pumped loop has several performance features, including: (1) reliable refrigerant circulation even when the refrigerant flow exiting the radiators is a two-phase flow during thermal transients; (2) reliable flow distribution in a network of evaporators to minimize flow maldistribution when instrument heat loads vary; (3) actively controlled two-phase refrigerant pressure at the evaporator inlet to precisely control evaporator cooling temperature; and (4) freeze-tolerant radiators. This paper first discusses the baseline layout design of Creare’s two-phase pumped loop system, and then describes a brassboard two-phase pumped loop test setup that is used to assess the effect of the system accumulator designs and its location in the loop. Finally, the paper compares the performance of pumped loops with different accumulator designs and installation locations during heat sink thermal transients.