Preliminary study on supercritical hydrogen and bleed air heat exchanger for aircraft application

In this paper, the new idea of the supercritical hydrogen–bleed air heat exchanger for future aircraft propulsion technology is investigated. The proposed heat exchanger will be located in the nacelle of commercial aircraft, and therefore is subjected to several geometrical constrains. At first, the initial geometry was proposed and then based on constrains and assumed operation conditions the main geometrical parameters and dimensions of the heat exchanger were calculated and optimized. The analyses were carried out by developing simple thermo-fluid 1D mathematical and numerical models of the heat exchanger, which were based on its geometrical features, directions of streams of hydrogen, and bleed air as well as on semi-empirical correlations for local Nusselt numbers and pressure drops for supercritical hydrogen and bleed air flows. The 1D model was partially validated using data from the experimental measurements. Then based on the obtained results, the final geometry of the supercritical hydrogen–bleed air heat exchanger was proposed.