Direct Numerical Simulation of Compressible Flow Past a Low Pressure Turbine Blade at High Incidence

Abstract

A direct numerical simulation (DNS) code has been developed to solve the compressible Navier-Stokes equations. This code is capable of handling unstructured grids, often a requirement for simulating flow past complex geometrical shapes like turbine and compressor blade passages. The code is validated for a compressible turbulent channel flow. Flow past a low pressure (LP) turbine blade passage is computed at Re = 51,831 based on axial chord length and incoming velocity, and angle of incidence = 45.5° with respect to axial chord. Several interesting fluid-dynamical phenomena including multiple separation bubbles and laminar-turbulent-laminar transition cycles are noticed on the suction side of the blade. Also a strong curvature effect is seen in the boundary layer near the leading edge on the suction side, where use of higher order boundary layer theory will be needed.