源项不准确加载对源项法模型仿真精度的影响

针对平板多孔气膜冷却结构开展了真实模型和源项法模型数值仿真,在同实验数据对比取得较高精度的基础上探究了源项不准确加载对源项法模型仿真精度的影响,分析了加载方式、流量系数、网格参数等影响因素。结果表明:源项法模型可以代替建立带气膜孔真实模型对气膜冷却结构进行数值计算。网格准确定位的源项加载方式在粗细网格条件下均能取得较高的精度,点源项加载方式对网格较为敏感。因流量系数公式不准确导致的流量计算误差会影响源项法模型的计算精度,低吹风比下影响更为显著。气膜孔进出口处网格面密度应不少于4个/mm2,第一层网格高度的选取应符合所选用的湍流模型,以保证较高的计算精度。

Effect of inaccurate source term loading on simulation ,precision for source term model

Numerical simulation of the real model and the source term model was carried out for a multi-perforated film cooling plate. On the basis of high-precision experimental comparison, the effect of inaccurate source term loading on the simulation results was explored, and the factors such as loading methods, discharge coefficient, and mesh parameters were analyzed. Results showed that the source term model could be used for numerical calculation of film cooling structure instead of establishing real holes with film hole. The source term loading method of accurate mesh positioning could achieve high precision under the coarse and fine meshes, while the point loading method was more sensitive to the grid. The mass flow rate calculation error caused by the inaccuracy of discharge coefficient empirical formulas would affect the calculation precision of the source term model, which was more pronounced at low blow ratios. The mesh density at the entrance and exit of the film hole should be not less than 4/mm2, and the height of first prism layer should be consistent with the turbulence model to ensure high simulation precision.