旋转楔形通道流动与换热特性的数值研究

Numerical Investigation of Flow and Heat Transfer Characteristics in a Rotating Wedge-Shape Channel

为了模拟涡轮叶片尾缘冷却通道的流动换热特性,建立了带侧向出流的旋转楔形冷却通道的数值模型,采用k-ωSST两方程模型研究了流动与旋转对于楔形通道内换热分布与不同出口冷气出流比例的影响。在静止情况下,由于沿程侧向的冷气出流,换热沿程降低。而旋转压缩了通道顶部内侧区域的流动滞止涡,导致内侧区域的换热显著增强。静止情况下沿程冷气出流占比不断提高,但雷诺数的影响有限。随着旋转数的提高,通道冷气出流比例受到旋转离心力的主导作用,前半段冷气出流比例下降,后半段出流比例上升,在50%径向高度位置为平均值。在大旋转数下(Ro>0.4),通道前半段冷气出流比例逐渐下降为0。通道安装角度的变化对冷气出流比例的影响有限。

In order to simulate flow and heat transfer characteristics in turbine blade trailing edge cooling channel,a numerical rotating wedge-shape channel with lateral coolant extraction was modeled. The standard k-ω SST turbulence model was applied for the simulation that focused on the flow and rotation factors on the heat transfer distribution and coolant extraction ratios in wedge-shape channel. At stationary case,the heat transfer level decreases along the channel due to the lateral flow extraction. But rotation compresses the end-wall vortex of the inner corner which causes higher heat transfer of the inner section. The coolant extraction ratio increases from the channel entrance to the end-wall at stationary. And the Reynolds number shows very limited influence. As the rotation number increases,the centrifugal force dominates the coolant extraction ratio. Less coolant are observed for the outlets near the channel entrance and more coolant flow through the down-stream outlets. At 50% radial location,it shows the average extraction ratio. Even more,the coolant mass flow rate ratio gradually decreases to0 at high rotation number（Ro0.4）. It is also found that the channel orientation shows limited effect on the coolant extraction ratio.