Numerical Study on the Influence of Jet Direction and Droplet Parameters on Jet Precooling Effect

TBCC engine is a new type of engine that integrates a turbine engine and ramjet engine design to achieve engine from start-up to high Mach number flight. Jet precooling technology injects cooling medium into the turbine inlet and achieves cooling effect on high-temperature incoming flow through evaporative phase change, effectively improving the upper limit of the turbine engine. This article establishes an inlet model with NACA0018 airfoil support, and uses the Standard k – ε turbulence model and DPM model to establish a calculation method for gas-liquid two-phase flow and heat transfer model. The influence of jet direction and water vapor ratio (W/A) on jet precooling effect is studied. The results indicate that the influence of jet direction on the cooling effect is the result of the combined action of the two orthogonal velocities of the droplet. As the droplet velocity increases, the optimal jet angle continuously increases. For low-speed droplets, a 180° jet angle has a worse cooling effect than a 0° jet angle. As the water vapor ratio increases, the cooling effect continues to enhance, but the evaporation rate decreases continuously. Excessive water vapor ratio seriously affects the safety of aircraft engines.