A High Flux Heat Exchanger for Military Avionics Part II: Test Results

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.