Investigation of influencing factors of hot streaks migration in high pressure stage of a vaneless counter-rotating turbine

Three-dimensional, viscous, and unsteady CFD simulations have been performed in order to reveal the influencing factors of hot streaks migration in high pressure stage of a vaneless counter-rotating turbine. Based on the numerical results, the comparison between the case with inlet hot streaks and case without inlet hot streaks is carried out, which shows that the effect of inlet hot streaks on the load distributions of high pressure turbine airfoils is not notable and the airfoil load distributions are directly related to the inlet pressure distributions. The predicted results also indicate that the circumferential and radial movements of the hot streaks were not observed in the high pressure turbine stator. This means that the combined effects of secondary flow and buoyancy are very weak in the high pressure turbine stator. The numerical results also prove that the circumferential flow angle effect at the inlet of the high pressure turbine rotor, secondary flow effect and buoyancy effect are the mainly influencing factors to directly affect the migration characteristics of the hot streaks in the high pressure turbine rotor.