Heat Transfer Measurements in a Turbine Centre Frame at Realistic Mach Number - Part 2: Influence of Combustor Hot Streaks

Abstract This paper investigates heat transfer in a Turbine Centre Frame (TCF), focusing on the effects of combustor temperature non-uniformities, more commonly referred to as hot streaks (HS). It is a continuation of earlier experimental research that analysed the impact of HS on the duct's aerodynamics. The present study now extends the research to heat transfer, addressing the previously identified need to better understand the adiabatic wall temperature distribution and the heat transfer coefficient (HTC) in the presence of HS. Part 1 of this work provides a detailed explanation of the mechanisms governing the HTC distribution in the absence of hot streaks and will be used as a baseline for discussing different scenarios presented here. Two clocking positions of hot streaks were tested, along with three different radial positions for each of the clocking scenarios. Additionally, different parameters of hot streak injection were varied, corresponding to hot streak temperature and velocity variations. Results indicate that while HS generally do not change the heat transfer coefficient distribution, the adiabatic surface temperature distribution is significantly affected. Most importantly, the surface with the highest HTC, the TCF shroud, was also found to have the highest adiabatic wall temperature increase due to hot streak injection in most of the investigated scenarios.