Abstract: To address the issue of severe power loss caused by high air inlet temperature faced by the Turbine-Based Combined Cycle (TBCC) engine under high flight Mach numbers, the scheme of liquid ammonia/aviation kerosene dual-coolant precooler was proposed. Numerical research on the flow and heat transfer characteristics of dual-coolant precooler was carried out, investigating the effects of air inlet velocity, inlet temperature, and non-uniform inlet condition on precooling performance. The distribution characteristics of air-side temperature field, velocity field, and turbulent kinetic energy were investigated. The air-side heat transfer and flow resistance were elucidated through field synergy theory. The streamline and vorticity analysis were conducted, and the spatial distribution mechanisms of wall temperature and heat flux in precooling channels were revealed. The heat transfer of precooling channels on the liquid ammonia side and the aviation kerosene side were analyzed using the Nusselt number. Quantitative evaluation of precooling performance was conducted by introducing entransy dissipation and air-side heat transfer coefficient. The numerical results indicate that due to the much higher specific heat capacity of liquid ammonia compared to aviation kerosene, the air temperature on the liquid ammonia side is lower than that on the aviation kerosene side. The downstream of liquid ammonia channel has a smaller reflux vortex system, corresponding to significantly lower turbulent kinetic energy than the aviation kerosene side. The liquid ammonia channel distributes more heat flux, resulting in higher air-side heat transfer coefficient and irreversible loss. The field synergy of aviation kerosene side is sensitive to changes in air inlet parameters. The air undergoes a severe heat transfer process with good heat transfer and high flow resistance, followed by a stable heat transfer process with poor heat transfer and low flow resistance; The influence of air inlet parameters on the field synergy of liquid ammonia side is relatively weak, and the heat transfer and flow resistance along the air flow direction are relatively stable.

Key words: TBCC precooler, liquid ammonia, aviation kerosene, field synergy, air-side heat transfer coefficient, entransy dissipation