Energy Separation in High Subsonic Turbine Cascade

Abstract

Trailing edge vortex shedding from a turbine cascade was numerically simulated for an exit isentropic Mach number of 0.79 and a Reynolds number of 2.8×106. The objective of this study is to clarify the time evolution of the vortex shedding process from a turbine blade and the mechanism of energy separation appearing in the wake. Calculations used a locally developed numerical code, employing a second-order AUSM scheme for inviscid numerical fluxes, a second-order implicit dual time method for time integration, and Detached Eddy Simulation for turbulence. Calculated results confirmed a non-uniform pressure distribution along the trailing edge, which was observed experimentally and different from a uniform distribution at low subsonic Mach number. The energy separation where instantaneous total temperature splits into hot and cold spots in the wake is caused by convection and vortex rotation. In addition, the formation and dissipation phases of vortices affect the energy separation.