斜劈缝涡轮导向叶片尾缘出流气体流动特性数值分析

通过RNG k-ε湍流模型求解可压流的N-S方程,研究燃气轮机涡轮导向叶片尾缘劈缝出流冷气的流动情况。对斜劈缝涡轮叶片的尾缘部分建立了二维模型,根据航空发动机工况设置边界条件并进行数值模拟。研究表明,由于外流和叶片叶盆尾缘厚度的影响,叶盆尾缘端部形成局部回流,叶片尾缘劈缝气体流出后受压力梯度的影响先抬起与叶背面分离,在流过一段距离后由于跨音速流膨胀波的作用,冷气流再次附着在叶背尾缘上。文章讨论了涡轮叶片叶盆不同尾缘厚度、倾斜角度、几何造型对尾缘劈缝处流体流动特性的影响,对比了不考虑外流流动影响时尾缘劈缝处流动情况的影响。 

Numerical Investigation of the Cooling Flow Downstream of a Turbine Guide Vane Trailing Edge Slot

In order to investigate the flow characteristics of cooling flow downstream of a turbine guide vane trailing edge slot,numerical methods of RNG k-ε turbulent model were solved.Two-dimensional model for numerical study was established and boundary conditions were set based on operation conditions.The results show a reversed-flow region is formed at the tip of the pressure side due to the influence of the outside hot combustion gas and the pressure side tip thickness.The pressure gradient makes the coolant flow exit from the trailing edge slot first separates from the trailing edge cut-back,and then affected by the expansion wave,the coolant gas re-attaches the cut-back of the trailing edge after passing a certain distance.This article discusses the influencing factors on the flow of pressure side tip thickness,pressure side angle and the geometric shape of pressure side tip.This article also makes a comparison between considering the combustion gas outside and the case that the flow of combustion gas is not taken into account.