Experimental and numerical study on liquid film cooling performance under heated wall condition

Liquid film cooling is broadly applied in the thermal protection of liquid rocket engine. An experimental system of liquid film cooling for a heated curved stainless-steel wall is built in this study to investigate the effects of jet mass flow rate, jet angle, and nozzle diameter on the cooling performance. The temperature distribution of the heated wall is demonstrated with infrared thermography technology and the flow spreading shape of the liquid film is captured with high-speed camera. A numerical liquid film cooling model based on the volume of fluid (VOF) coupled Level-set method is established to calculate the evaporative heat absorption and spreading shape of liquid film. The experimental study indicates that the peak film thickness in the hydraulic jump region increases with the jet mass flow rate, such as the peak film thickness increases from 265.15 to 632.25 mu m at Q = 100-600 mL.min(-1). Besides, a jet angle of 35 degree can maintain the maximum wall temperature drop of 29.4 degrees C. In addition, the simulated peak film thickness presents a minimum deviation of 5.2 % from the experimental data. The numerical model provides important reference for the study of liquid film cooling performance of the liquid rocket engine.