Numerical study of the flow field through a transonic linear turbine cascade at design and off-design conditions

The flow field through a transonic linear turbine cascade is studied in this paper at design and off-design conditions. The compressible flow field is obtained by solving the equations governing the fluid flow and heat transfer. Two eddy-viscosity turbulence models are used to simulate the turbulence in turbine cascades: the standard k-epsilon model and the Spalart-Allmaras model. The standard k-epsilon model is the most universal and popular model for industrial flow and heat transfer simulations. It has the shortcoming of accurately predicting the profile loss in turbomachinery applications. The Spalart-Allmaras model is a relatively recent and simple one-equation model. In this paper, the model is tested for turbomachinery applications. The ability of the model to accurately predict the flow field in turbine cascade is tested. Blade loading, downstream wake distribution, total pressure loss coefficient, and exit flow angle are used in this study with comparisons to the standard k-epsilon model and experimental data. The design condition and the off-design conditions are considered.