Studies on Unsteady Turbulence Flow Characteristics Associated With Stator-Rotor Interaction Originated Thermal Flow Phenomena Using a High Order LES Model

Abstract

Abstract Unsteady turbulence phenomena caused by stator-rotor interaction in today’s gas turbines which operates at higher temperature to meet the demand of increase in cycle performance by creating severe heat load in the turbine stages is a challenging problem worth paying attention. To avoid the damage of the material from high mean flow temperature cooling of both end-walls and the blades is very much essential. Understanding of the aerodynamics involved is important to implement the cooling technique. To study these phenomena 3-D unsteady Navier-Stokes analysis of a turbine stage is carried out as a base case. The experimentally observed effect of hot streak on the surface temperature distribution of the rotor blade and the unsteady pressure fluctuation associated with stator-rotor interaction are very well predicted by the numerical results. Since the flow associated with stator-rotor interaction is highly unsteady in nature, it is very important to have some understanding of the unsteady turbulence characteristics (unsteady nature of turbulence production and its dissipation and the corresponding fluctuation of pressure and temperature) in this type of thermal flow phenomena. After comparison of computed and experimental results, in our study emphasis is put to understand the unsteady turbulence characteristics based on turbulence production and its dissipation and the corresponding Q-criterion associated with stator-rotor interaction thermal flow phenomena.