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应用Standard k-=紊流模型并结合SIMPLE算法,近壁区流动的处理采用壁面函数法,对燃气轮机首级静叶产生的非定常尾迹及动叶流场进行数值模拟。通过在动叶前放置直径为d=2、4、6 mm的圆柱来模拟静叶尾迹的宽度,研究不同时刻尾迹宽度对下游动叶传热特性的影响。结果表明:静叶产生的尾迹对下游动叶压力面与吸力面的速度影响呈现周期性变化,圆柱尾迹产生的速度亏损,使主流的流速降低,压力面低速回流区在1/4T时刻达到最大。低吹风比M=0.5时,尾迹宽度增大(d=4 mm)能使压力面传热增强,而吸力面的传热变化很小,但过高的尾迹宽度(d=6 mm)将会同时降低压力面和吸力面的努赛尔数。高吹风比M=1.5时,随着尾迹宽度增大,压力面和吸力面的传热均增强,在d=6 mm时努赛尔数达到最大。
The standard k - = turbulence model and the SIMPLE algorithm are used to simulate the unsteady wake and flow field generated by the first stage vane of the gas turbine by wall function method. The effect of wake width on the heat transfer characteristics of downstream moving lobe at different moments was studied by placing a cylinder of d = 2, 4, 6 mm diameter in front of the moving blade to simulate the width of the wake. The results show that the wake produced by the vanes has a cyclical change in the velocity of the pressure side and the suction side of the downstream lobe, and the velocity loss caused by the circular wake reduces the flow velocity of the main flow and reaches the maximum at 1 / 4T . The increase of wake width (d = 4 mm) with low blow ratio M = 0.5 results in enhanced heat transfer on the pressure surface and little change in heat transfer on the suction surface, but an excessively high traverse width (d = 6 mm) Lower the Nusselt number for the pressure and suction surfaces. When M = 1.5, the heat transfer between the pressure surface and the suction surface increases with the increase of the wake width, and reaches the maximum at d = 6 mm.