Ultra-Compact Heat Exchangers

Makai Ocean Engineering, Inc. proposes to address thermal management performance shortfalls for 6th generation air platforms by developing a novel heat exchanger technology. Specifically, Makai will develop an ultra-compact foil based heat exchanger (FFHX) for air-cooled, two-phase vapor cycle systems. The FFHX will provide at least a 50% improvement in volumetric performance, pressure drops of less than 1psi, and lower weights compared to the current state-of-the-art.The FFHX manufacturing process uses advanced and high-precision techniques that enable use of thin foils (0.0015 inch), custom flow geometries, surface enhancements, elimination of backing plates and tension rods, and most importantly enabling irregular and non-rectilinear heat exchanger volume envelopes.Computational fluid dynamics (CFD) simulations show air-convection coefficients of at least 350 W/m2-K. Combined with surface area densities of 2000 m2/m3, this results in more than 50% improvement in volumetric performance compared to the Honeywell metrics. Makai will work with LM Aero to achieve additional performance improvements by exploiting irregular, peripheral spaces in the air platform, which is not possible with current state-of-the-art units.Prototype plates have been pressure tested to over 500 psi at Makais facility in Hawaii, making this a relatively low-risk development and shortening the transition timeline for the USAF.