COMPUTATIONAL MODELING OF 3-DIMENSIONAL ENDWALL FLOW-THROUGH A TURBINE ROTOR CASCADE WITH STRONG SECONDARY FLOWS

A steady, three-dimensional Navier-Stokes solver that utilizes a press ure-based technique for incompressible flows is used to simulate the t hree-dimensional flow field in a turbine cascade. A new feature of the numerical scheme is the implementation of a second-order plus fourth- order artificial dissipation formulation, which provides a precise con trol of the numerical dissipation A low-Reynolds-number form of a two- equation turbulence model is used to account for the turbulence effect s. Comparison between the numerical predictions and the experimental d ata indicates that the numerical model is able to capture most of the complex Pow phenomena ir? the endwall region of a turbine cascade, exc ept the high gradient region in the secondary vortex core. The effects of inlet turbulence intensity and turbulence length scale on secondar y vortices, total pressure loss, and turbulence kinetic energy inside the passage are presented and interpreted It is Sound that higher turb ulence intensity energizes the vortical motions and tends to move the passage vortex away from the endwall. With a larger turbulence length scale, the secondary flow inside the passage is reduced However, the t otal pressure loss increases due to higher turbulence kinetic energy p roduction.