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Test results are described for a coldplate heat exchanger designed to remove electronics heat loads of up to 100 W/cm2 while maintaining device junction temperatures of 90 °C. The heat exchanger was designed to operate within a notional fighter aircraft environment with the following constraints: 0 °C minimum coolant temperature, poly alpha olefin (PAO) coolant, and minimized flow rate and pressure drop. The heat exchanger was configured to Standard Electronics Module, Format “E” (SEM-E) specifications. High heat flux capability was achieved by combining the high heat transfer characteristics of multiple jet impingement with the compact extended surface area enhancement of laminated construction. Thermal tests verified 100 W/cm2 local capability, and 2000 W total module heat load capability, with wall-to-fluid thermal resistance of 0.281 °C/(W/cm2). Repeatable thermal and hydraulic performance was obtained over a one-month period of testing, including 22 hours of flowing coolant.

Numerous studies have concluded that improved high power density cooling methods are required for future avionics due to the trends in increasing heat dissipation, device miniaturization and higher packaging density. A high flux heat exchanger (HFHE) has been designed to optimally meet the thermal performance and envelope requirements selected as appropriate for future avionics, at a minimum impact to the host aircraft. This paper summarizes the design and fabrication of the prototype HFHE. The HFHE has been successfully performance tested with results included in Part II of this paper. Design objectives for the HFHE included a local heat flux capability of 100 W/cm2 (at 20 one-cm2 sites), a total SEM-E size module heat load of 2,000 W, and a maximum device junction temperature of 90°C with PAO coolant at not less than 0°C. An aluminum frame coldplate with a laminated copper heat transfer insert was designed and fabricated which met all of these performance requirements.

Space Station Freedom employs a pump module to provide fluid pumping, fluid pressure and temperature regulation, and fluid management in its active thermal control system. The pump module utilizes a multifunction pitot pump for fluid pumping, a servo actuated vapor regulator for fluid pressure and temperature regulation, and an accumulator to aid with fluid management. Pump module component designs are tailored to the specific requirements of the thermal control system. Prior to use on the Space Station, the pump module will undergo a comprehensive test program that includes engineering development tests and flight qualification tests.