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本文将“Partially Parabolic”流动假设运用于有纵向曲率、有压力梯度、壁面有排孔喷射的弯曲通道内,孔附近气膜冷却流场。支配方程是部分抛物化的Navier-Stokes方程及滞止焓方程。湍流粘性系数由K-8双方程模型决定,而在边界层内层区则采用双层模型。在本文所建议的变步长准正交曲线坐标系下,用有限差分法对平坦通道及弯曲通道凸壁面一侧离散孔垂直喷射及斜向喷射气膜冷却有效温比作了计算。在吹风比较小的条件下,计算结果清楚地显示了三维气膜冷却的特征。与已有的典型实验结果比较,变化趋势是完全一致的。对于吹风比较大的情况,则必须求解完全的Navier-Stokes方程。
In this paper, the “Partially Parabolic” flow assumptions are applied to the flow field of the film cooling in the curved channel with longitudinal curvature, pressure gradient and perforated spray on the wall. The governing equation is partially parabolic Navier-Stokes equation and stagnation enthalpy equation. The turbulent viscosity coefficient is determined by the K-8 two-equation model, while the bilayer model is used in the inner boundary layer. In the proposed quasi-orthogonal curvilinear coordinate system with variable step size, the finite difference method is used to calculate the effective temperature ratio of the vertical and oblique jet cooling of the cooling air in the flat channel and the convex wall side of the curved channel. The calculation results clearly show the characteristics of the three-dimensional film cooling under the conditions of small blowing. Compared with the typical experimental results, the changing trend is completely consistent. For the case of large blowing, you must solve the complete Navier-Stokes equations.