CFD Meshing and Simulation Best Practices for a Turbine Stage With Squealer Tips, Trailing-Edge Cooling and End-Wall Cooling Injection

The present study discusses and verifies workflows for simulating the flow through turbine stages featuring complex geometry like cooling holes at the hub and shroud surfaces, cavities upstream and downstream of the rotor, and rotor blades with squealer tips. Linne et al. [3] investigated such a configuration experimentally. Their experiments served as the test case for the present simulations. The geometric complexities forbid using mapped hexahedral meshes, the mesh elements of choice for standard geometries. Therefore, the first part of the paper investigates the use and accuracy of unstructured polyhedral meshes by comparing their accuracy and computational efficiency to hexahedral meshes on a reduced geometry model. The second part applied unstructured polyhedral meshes to the complete geometry model. The simulations showed that adding trailing edge cooling and rotor cavities prevents convergent steady-state solutions on the finer meshes. Rotor cavities and trailing edge cooling had a perceptible influence on the calculated isentropic efficiencies.