Numerical Investigation of Three-Dimensional Turbulent Flow and Endwall Heat Transfer in a Large-Scale Cascade of Turbine Blades

摘要

Numerical simulation is performed of three-dimensional turbulent flow and heat transfer in a cascade of turbine blades (Langston cascade), for which numerous data are available in the literature. For closing the system of Reynolds-averaged Navier - Stokes equations, use is made of two-parameter models of turbulence of the k - ω family, low-Reynolds version of the Wilcox model, and the SST model of Menter. Numerical solutions are obtained in detailed grids (over a million cells) using the finite-volume code of second-order accuracy. It is demonstrated that the predicted structure of flow and local heat transfer on the end wall are very sensitive to the choice of model of turbulence, especially in the case of a thick boundary layer at the cascade inlet. By and large, the use of the Menter model enables one to well reproduce the complex vortex structures of flow in the cascade, as well as the local and integral characteristics of loss of total pressure. The local endwall heat transfer is predicted adequately.