Introduction

Film cooling is a process that is used to protect turbine vanes in a gas turbine engine from exposure to hot combustion gases. This tutorial illustrates how to set up and solve a film cooling problem using a non-conformal mesh. The system that is modeled consists of three parts: a duct, a hole array, and a plenum. The duct is modeled using a hexahedral mesh, and the plenum and hole regions are modeled using a tetrahedral mesh. These two meshes are merged together to form a "hybrid'' mesh, with a non-conformal interface boundary between them.

Due to the symmetry of the hole array, only a portion of the geometry is modeled in ANSYS FLUENT, with symmetry applied to the outer boundaries. The duct contains a high-velocity fluid in streamwise flow (Figure  7.1). An array of holes intersects the duct at an inclined angle, and a cooler fluid is injected into the holes from a plenum. The coolant that moves through the holes acts to cool the surface of the duct, downstream of the injection. Both fluids are air, and the flow is classified as turbulent. The velocity and temperature of the streamwise and cross-flow fluids are known, and ANSYS FLUENT is used to predict the flow and temperature fields that result from convective heat transfer.

This tutorial demonstrates how to do the following:

• Merge hexahedral and tetrahedral meshes to form a hybrid mesh.

• Create a non-conformal mesh interface.

• Model heat transfer across a non-conformal interface with specified temperature and velocity boundary conditions.

• Calculate a solution using the pressure-based solver.

• Plot temperature profiles on specified isosurfaces.