Browsing by Author "Conboy, Thomas M."
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item Development of a Miniature, Reliable Ammonia Pump for Spaceborne Two-Phase Pumped Loops(49th International Conference on Environmental Systems, 2019-07-07) Chen, Weibo; Conboy, Thomas M.; Daines, GregoryNASA’s future remote sensing science missions require advanced thermal management technologies to maintain multiple instruments at very stable temperatures and utilize waste heat to keep other critical subsystems to stay above minimum operational temperatures. Two-phase pumped loops are an ideal solution for these applications. A critical need for these pumped loops is an ammonia pump that reliably circulates very slightly subcooled liquid ammonia in the loop. To meet this need, Creare is developing a reliable, pump that has innovative features to prevent cavitation in the pumping chamber and in the hydrodynamic fluid bearings, enhancing the overall pumped loop reliability. This paper first discusses design challenges for ammonia circulation pumps for two-phase pumped loop applications. It then discusses the key performance features of Creare’s ammonia-compatible pump and presents the hydrodynamic performance test data of a brassboard pump and its measured Net Positive Suction Head before cavitation occurs. Finally, the paper discusses the preliminary assessment of the pump reliability and exported vibrations.Item A Robust Two-Phase Pumped Loop with Multiple Evaporators and Multiple Radiators for Spacecraft Applications(47th International Conference on Environmental Systems, 2017-07-16) Chen, Weibo; Conboy, Thomas M.; Daines, Gregory W.; Fogg, David W.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.