UNSTEADY ANALYSIS OF HOT STREAK MIGRATION IN A TURBINE STAGE

Experimental data taken from gas turbine engines have shown that hot streaks existing combustors can have a significant impact upon the secondary flow and wall temperature of the first-stage turbine rotor. Understanding the secondary flow and heat transfer effects due to combustor hot streaks is essential to turbine designers attempting to optimize turbine cooling systems. A numerical investigation is presented that addresses the issues of multiblade count ratio and three-dimensionality effects on the prediction of combustor hot-streak migration in a turbine stage. The two- and three-dimensional Navier-Stokes analyses developed by Rai et al. are used to predict unsteady viscous rotor-stator interacting flow in the presence of a combustor hot streak. Predicted results are presented for a two-dimensional three-stator/four-rotor, a two-dimensional one-stator/one-rotor, and a three-dimensional one-stator/one-rotor simulation of hot-streak migration through a turbine stage. Comparison of these results with experimental data demonstrates the capability of the three-dimensional procedure to capture flow features associated with hot-streak migration including the effects of combustor hot streaks on turbine rotor surface temperatures.