The Trans-critical Process Control of Hydrogen Based on a Flow Distribution Method for Enhancement of Heat Transfer

The heat transfer performance of the thermal management system plays a crucial role in the hydrogen-powered aviation engine cycle. As an exceptional fuel, the thermophysical parameters of hydrogen change drastically with temperature in the trans-critical state. While previous studies on heat transfer enhancement mainly focused on changing the geometrical structure, few studies have been conducted on realizing heat transfer enhancement based on the properties of the fluid itself. Utilizing the drastic changes in thermophysical parameters of hydrogen in the trans-critical state to achieve heat transfer enhancement could greatly contribute to the thermal management system of the hydrogen-powered cycle. In this study, a trans-critical process control method for heat transfer enhancement based on multidirectional impact flow distribution is proposed. The distributions and variation patterns of temperature, density, specific heat capacity, and equivalent thermal conductivity along the flow directions were investigated, the flow and heat transfer performance of the channel optimized by the proposed method was numerically simulated, and the control of the trans-critical process and the mechanism of heat transfer enhancement were analyzed. The effects of the key design parameters such as flow distribution ratio, number, and spacing of gaps on the flow and heat transfer performance of the heat transfer unit were comparatively analyzed by taking various factors into account, and finally, a relatively optimal combination of key design parameters was obtained.