A Prescribed Velocity Distribution Scheme for Turbomachine Blading

Abstract

The work describes a quasi three dimensional time marching method (Euler Solver), allowing for variations in streamtube height and radius in the meridional plane, for the generation of blade shapes. The method is applicable for both compressor and turbine blades. The generation of the blade shapes is done corresponding to a prescribed pressure distribution (with or without shock waves) around the blade surfaces. The method can be used to either generate entire blade shapes or to modify regions of an existing inefficient blade shape. Viscous effects are allowed for by using an integral boundary layer growth method in the scheme. For the generation of turbine blade shapes the effects of trailing edge base pressure are also included in the method. The accuracy of the scheme has been demonstrated through various test cases. The use of the method results in vast reduction in overall design time and hence cost.

Unsteady Flow in a Single Stage Turbine

“…This would enable the unsteady calculation to be based on the best possible model of the time averaged performance of the stage. The required streamtube thickness was calculated using an inverse method developed by Singh (1996). and is shown in Figure 7 to be quite different to that from the throughflow calculation.…”