The Prediction of Three-Dimensional Discrete-Hole Cooling Processes: Part 2—Turbulent Flow

Computer simulations are described of the injection of a secondary coolant fluid through a row of downstream-facing holes arranged across a surface exposed to a hot parallel gas stream, as occurs in certain discrete-hole cooling systems for turbine blades. The simulation is performed by solving the governing equations numerically, with the effects of turbulence modelled in a way which allows for the anisotropies existing in the real situation. Comparisons with measurements obtained for injection angles of 30 deg and dimensionless blowing rates in the range 0.2 to 0.5 show good agreement in the majority of cases. Discrepancies are however observed at conditions of small upstream boundary layer thickness or large injection rates and the causes of these are identified and discussed.