高温气体流过圆管时壁面发散冷却的数值模拟

Numerical simulation of high temperature transpiration cooling in cylindrical porous channels

对超高温燃烧室发散冷却全场进行有效的数值模拟对燃烧室材料结构设计具有重要的意义。该文通过FLUENT6．1，采用RNG k-ε湍流模型，建立了高温气体流过圆管时多孔介质壁面发散冷却的全场耦合数值计算模型。该模型计算结果与低温氦气、低温空气发散冷却实验结果基本吻合。该文研究了常温氢气对超高温燃烧室内燃气的发散冷却，结果表明，忽略对流传质边界层的影响会导致计算预测的壁面温度偏高，忽略孔隙率局部分布的不均匀性会导致冷却壁面端部出现高温计算结果，这不符合常理。在注入率为1％左右时，冷却壁面温度在400～900K的范围内，壁面局部热流密度降至200kW／m^2左右，可以满足航天器燃烧室保护壁面的需要。

Efficient numerical predictions of the heat transfer in super high temperature engines are needed to design effective combustion structures. A whole-field numerical simulation of high temperature transpiration cooling in a cylindrical porous channel was developed using Fluent 6. 1 with the RNG k-ε turbulence model. The numerical results agreed well with experimental data for low temperature air and helium transpiration cooling. The model was then used to investigate GAS/GH2 transpiration cooling. The results indicate that neglecting the mass transfer will lead to much higher predicted wall temperatures, while neglecting the local porosity distribution will lead to high local temperature errors along the front part of the wall. For a 1% blowing ratio, the local heat flux was reduced to 200 kW/m^2 and the wall temperature was reduced to 400-900K, which is acceptable for rocket combustion chamber wails. ：