Session: 12-03 Experimental techniques and scaling

Paper Number: 126110

126110 - Revisiting Dimensionless Parameters Quantifying Film Cooling 

Film cooling of a configuration has typically been characterized by the blowing and the momentum flux ratios or by the density and velocity ratios, where the density ratio is often replaced by the temperature ratio.  Are these parameters sufficient to fully characterize the film cooling of that configuration?  This question is addressed in this study via conjugate CFD (computational fluid dynamics) simulations, based on steady Reynolds-Averaged Navier-Stokes (RANS) with the Shear-Stress Transport (SST) turbulence model.  The configuration studied is film cooling of a flat plate, where the coolant, issuing through 30-degree inclined circular holes, is fed from a narrow channel with a direction of flow that is 90 degrees with respect to the direction of the hot-gas flow (referred to as crossflow fed).  In this study, the mass-flow rate in the cooling channel was varied while keeping the blowing and temperature ratios (BR and TR) constant.   Results obtained with BR = 0.75 and 1.0 and TR = 1.9 show reducing the mass flow rate in the cooling channel by one half to slightly affect the discharge coefficient (<5%) but up to 25% on overall cooling effectiveness and up to 85% on laterally-averaged adiabatic effectiveness.  Results are presented to show flow mechanisms that lead to these changes.  Results from a dimensional analysis is also presented to identify the additional dimensionless parameters that must be included to fully characterize the film cooling of this configuration.  This computational study was validated by comparing results with experimental data generated at the NETL Conjugate Aero-thermal Test Rig.  

Presenting Author: Tom Shih Purdue University

Presenting Author Biography: Tom Shih is professor of Aeronautics and Astronautics at Purdue University.

Authors:

Chien-Shing Lee Purdue University
Tom Shih Purdue University
Douglas Straub National Energy Technology Laboratory
Justin Weber National Energy Technology Laboratory