Unsteady Numerical Simulations of Radial Temperature Profile Redistribution in a Single-Stage Turbine

Abstract

Experimental data taken from gas turbine combustors indicate that the flow exiting the combustor can contain both circumferential and radial temperature gradients. A significant amount of research recently has been devoted to studying turbine flows with inlet temperature gradients, but no total pressure gradients. Less attention has been given to flows containing both temperature and total pressure gradients at the inlet. The significance of the total pressure gradients is that the secondary flows and the temperature redistribution process in the vane blade row can be significantly altered. Experimental data previously obtained in a single-stage turbine with inlet total temperature and total pressure gradients indicated a redistribution of the warmer fluid to the pressure surface of the airfoils, and a severe underturning of the flow at the exit of the stage. In a concurrent numerical simulation, a steady, inviscid, three-dimensional flow angle distribution, In the current research program, a series of unsteady two-and three-dimensional Navier–Stokes simulations have been performed to study the redistribution of the radial temperature profile in the turbine stage. The three-dimensional analysis predicts both the temperature redistribution and the flow underturning observed in the experiments.

Effect of Inlet Conditions on Endwall Secondary Flows

“…Analyses of combustor hot streak simulationsthrough turbine stages have shown that, when a temperature pro le does not alter the total pressure pro le, there is no impact on the resulting secondary ows in the rst-stage stator vane. 11¡ 13 Simulationsby Dorney and Schwab, 14 which includeboth temperature and total pressure gradients,show an affect on vane and rotor secondary ows with signi cant temperature redistribution at the rotor exit.…”