CFD Analyses of a Single Stage Turbine With Inlet Hot-Streak at Different Circumferential Locations

This paper presents a detailed flow and heat transfer characteristic analysis on a gas turbine first stage under hot-streak inlet conditions. Simulations were performed for two locations of hot-streak at turbine inlet with respect to the first stage vane, i.e. i) passage center and ii) blade center. The two kinds of inlet conditions have the same mass-averaged total temperature and total pressure. The passage center hot-streak total pressure and total temperature contours are obtained from the rig data published by Butler. Linear interpolation technique is used to move the hot-streak location from passage center to blade center. The ratio of highest temperature in hot-streak to free stream temperature is 2.0. Mixing plane (MP) and Non-linear harmonic (NLH) approaches are used to address the data transport across the rotor-stator station interface. The numerical solution is validated with the test data obtained from the published rig tests. NLH approach predicted the rotor blade surface temperature distributions close to rig data with a percentage deviation of 3%. The change in hot-streak circumferential position from blade center to passage center lead to decreased attenuation of hot-streak due to pronounced cross momentum transport of fluid across the viscous layers. Turbine flow with blade center hot-streak experiences transient periodic fluctuation of heat load on rotor surface. High temperature gradients are observed at turbine exit station with passage center hot-streak.