高负荷透平叶片流动机理及湍流特性研究

Study on Flow Mechanisms and Turbulence Characteristics of a Highly-Loaded Turbine Blade

透平叶栅端壁处存在强的二次流动和多种涡系的相互作用,在通道内部产生明显损失。精确捕捉高负荷透平内部流动结构,对传统RANS方法提出巨大挑战,本文采用自主开发的DDES求解程序,研究高负荷透平叶片端区涡系结构、流动机理和湍流特性。采用POD方法研究流道下游湍流脉动主导因素,对比RANS方法和DDES方法对于雷诺应力的解析能力,采用总压损失系数对流场损失进行分析,结果表明DDES方法在高负荷透平内部端区求解三次涡结构、端区压力分布和损失分布等具有特殊优势。

In turbine blades endwall area,that the interaction between the strong secondary flow and various vortices results in big aerodynamic losses.To capture the fine flow structures in highly-loaded turbine endwall areas challenges the traditional RANS method.The work adopts DDES method to investigate the vortex structures,flow mechanisms and turbulence characteristics near the highly-loaded turbine blade endwall.POD method has been used to research the dominant factors of turbulence fluctuation near the endwall.The paper compares the Reynolds stresses results between the RANS and DDES method.The losses near the endwall have been analyzed by using the total pressure loss ratio.The results show that the DDES method has its special advantages in simulating the third vortex structure,endwall area pressure and losses distribution.