液体火箭发动机燃烧室壁液膜冷却的数值模拟

为研究液体火箭发动机的液膜冷却，建立了液膜模型。考虑核心气流与液膜间的对流传热，辐射传热以及壁面与液膜的对流传热分析传热量，由液膜的卷吸和液膜的蒸发计算传质，并由气液界面和液固界面的摩擦力分析流动情况。在400N小发动机内流场数值模拟中采用了该液膜模型，计算得到的壁面温度分布与试验结果符合较好，表明该模型是合理可行的。改变发动机燃烧室半径和圆筒段长度，将数值模拟结果对比分析发现:在一定范围内随着半径和圆筒段长度的增加，液膜长度减小，室壁温度升高，冷却效果变差。研究结果可为发动机的设计提供参考。 

Numerical simulation of liquid film cooling for combustion chamber wall of liquid rocket engine

To study the liquid film cooling in liquid rocket engine, a liquid film model was established. The convection heat transfer and radiative heat transfer between the core flow and the liquid film, and the convection heat transfer between the wall and the liquid film were considered to analyze the heat quantity. The mass transfer inducing the entrainment and evaporation of the liquid film was calculated. The friction force between gas-liquid interface and liquid-solid interface was used to analyze the film flow. The model was used in the numerical simulation of flow field within a small engine with 400N thrust. The numerical simulation results were in good agreement with the test data, showing that the model is reasonable and feasible. Comparative analysis of simulation results of different radius and the length of cylinder section of the combustion chamber revealed that within a certain range, with the increase of the radius and the length of the cylinder section, the liquid film length decreased, and the chamber wall temperature increased, so the cooling effect became worse, the result can offer a reference for the liquid rocket engine design.