高马赫数涡轮发动机射流预冷特性研究

The mass injection precooled turbine-based engine has an important demand for cooling water and liquid oxygen at high altitude and high Mach number. A numerical analysis of water liquid-oxygen injection cooling was conducted in the pre-cooling section of high-altitude simulation test inlet air, which was based on the gas-liquid phase change cooling mechanism. Considering the thermodynamic phenomenon of the real droplet movement, the flow field characteristics during the heat and mass transfer process of gas-liquid two-phase were analyzed based on the Eulerian-Lagrangian multiphase flow method. The effects of water-liquid mixture injection on the flow and heat transfer characteristics of the pre-cooling section were discussed in a high Mach number turbine engine. Results show that the effect of atomization evaporation of water liquid-oxygen injection is instantaneous. Based on the advantages of large specific heat and vaporization enthalpy of water mist, water injection concentration is dominant to the total temperature drop and total pressure recovery of the mainstream, while liquid oxygen injection concentration is beneficial to reduce the heat flux density of wet air mixture. When the mass injection concentration is in the range of 2%~8%, the total-pressure drop coefficient is 0.84%~1.27%; then, the total-temperature drop coefficient ranges from 2.15%~15.12%, that is, the temperature drop is 12.92~90.89K. To balance the demand of cooling water and liquid oxygen at high Mach number, it is necessary to control the water-liquid oxygen injection ratio. Especially, the mass flow rate of liquid oxygen recommends not to be higher than 60% of the total mass injection concentration. Moreover, the flow and heat transfer characteristics in the pre-cooling section are locally optimal when the mass injection ratio is '40% water-60% liquid oxygen'. When the physical speed of the engine remains unchanged, the inflow mass flow rate of wet air mixture increases by 0.22%~9.39% within the precooling section after mass injection pre-compressor cooling. For an increasement in mass flow, the contribution shares of dry air and water vapor are about 71.8% and 28.2%, respectively. Therefore, mass injection pre-compressor cooling is conducive to a higher acceleration of turbine engine at a high Mach number.