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以带有35°角圆形喷射孔的平板实验件为对象,计算了表面粗糙度k s=0.254、0.423和0.8 mm,气体主流雷诺数分别为5×105、8×105、106和2×106,吹风比分别为0.5、1.0、1.5等工况下的气膜冷却有效度和换热系数。通过数值计算结果与实验数据的对比,验证了Viegas-Jayatilleke模型可以应用于带有喷吹的发散湍流边界层的计算。计算结果表明,表面粗糙度在绝大部分区域提高了侧向平均气膜冷却有效度,影响值不超过10%,但粗糙度对换热系数的影响很大,最大提高50%。粗糙度存在也增加了主流雷诺数和吹风比对气膜冷却效果的影响。
The surface roughness ks = 0.254, 0.42 3 and 0.8 mm were calculated for flat plate test pieces with round holes of 35 °. The main gas Reynolds numbers were 5 × 105, 8 × 105, 106 and 2 × 106, respectively , Respectively, the blowing ratio of 0.5, 1.0, 1.5 and other conditions of the film cooling effectiveness and heat transfer coefficient. By comparing the numerical results with the experimental data, it is verified that the Viegas-Jayatilleke model can be applied to the calculation of the divergent turbulent boundary layer with injection. The calculated results show that the surface roughness improves the effective cooling efficiency of the lateral airtight film in most areas with the influence value of not more than 10%, but the roughness has a great influence on the heat transfer coefficient, up to 50%. The presence of roughness also increases the effect of the mainstream Reynolds number and blow ratio on the film cooling effect.