Effect of inlet conditions on endwall secondary flows

Exit combustor flow and thermal fields entering downstream stator vane passages in a gas turbine engine are highly non-uniform. These flow and thermal fields can significantly affect the development of the secondary flows in the turbine passages attributing to high platform heat transfer and large aerodynamic losses. This paper presents an analysis of the effects of both the temperature and velocity profiles on the secondary flows in the end wall region of a first stage stator vane geometry. These effects were assessed using the predicted flow field results from computational fluid dynamics (CFD) simulations. Prior to using the predictions, these CFD simulations were benchmarked against flow field data measured in a large scale, linear, turbine vane cascade. Good agreement occurred between the computational predictions and experimentally measured secondary flows. Analyses of the results for several different cases indicate the stagnation pressure gradient is a key parameter in determining the character of the secondary flows.