Comprehensive validation of an intermittency transport model for transitional low-pressure turbine flows

Abstract

AbstractA transport equation for the intermittency factor is employed to predict transitional flows under the effects of pressure gradients, freestream turbulence intensities, Reynolds number variations, flow separation and reattachment, and unsteady wake-blade interactions representing diverse operating conditions encountered in low-pressure turbines. The intermittent behaviour of the transitional flows is taken into account and incorporated into computations by modifying the eddy viscosity, μτ with the intermittency factor, γ. Turbulent quantities are predicted by using Menter’s two-equation turbulence model (SST). The onset location of transition is obtained from correlations based on boundary-layer momentum thickness, accelaration parameter, and turbulence intensity. The intermittency factor is obtained from a transport model which can produce both the experimentally observed streamwise variation of intermittency and a realistic profile in the cross stream direction.The intermittency transport model is tested and validated against several well documented low pressure turbine experiments ranging from flat plate cases to unsteady wake-blade interaction experiments. Overall, good agreement between the experimental data and computational results is obtained illustrating the predicting capabilities of the model and the current intermittency transport modelling approach for transitional flow simulations.