Blade Film Cooling

Description

This project simulates film cooling on a gas turbine blade — the technique that lets turbine blades survive gas temperatures well above their material limits by holding a thin layer of cool air against the surface. The cooling air, bled from the compressor stage, is fed through internal channels and ejected through discrete holes to form a protective film over the blade.

Methodology

The study is set up as a conjugate heat transfer (CHT) problem: the fluid domain (hot gas and cooling air) and the solid blade are coupled at the walls, so heat conducts through the blade while the external hot gas and the internal/film cooling air exchange heat with it simultaneously. Turbulence is modeled with k-ω SST, which resolves both the near-wall film behavior and the free-stream mixing between cool and hot streams. Geometry is built in Design Modeler, meshed in ANSYS Meshing, then converted to a polyhedral mesh (~2.7 million cells) in ANSYS Fluent for better gradient resolution and faster convergence around the cooling holes.

Analysis

Pathlines trace the cooling air through the blade's internal channels and out through the film holes, where it forms a thin thermal barrier over the surface. Film thickness varies along the blade — thickest near the holes — and the film is turbulent, mixing with the hot gas downstream and progressively losing effectiveness. The simulation makes the core design trade-off visible: hole size, shape, spacing, count, and injection angle all control how well the film holds before the hot gas entrains it, giving a clear basis for evaluating film cooling performance from temperature fields and pathline behavior.