Session: 12-13 General Film Cooling I

Paper Number: 82675

82675 - Computational and Experimental Study of Film-Cooling Effectiveness With and Without Downstream Vortex Generators 

Film cooling is widely used to cool turbine components exposed to hot gases such as vanes, blades, and endwalls by forming an insulating layer of cooler air about them.  However, cooling jets that form the insulating layer induce counter-rotating vortices (CRVs) that lift cooling jets off the surfaces that they are intended to insulate.  A new design – referred to as Downstream Vortex Generators (DVGs) – that involve a pair of rectangular plates arranged in a V shape placed just downstream of each film-cooling hole was shown to create vortices that entrain lifted cooling flow back to the surface and to increase the cooling jets lateral spreading on the surface (GT2020-14317).   In this study, computations and measurements were performed to assess DVGs’ ability in improving the effectiveness of film cooling a flat plate with the cooling jets emanating from one row of inclined holes.  Parameters studied included blowing ratio (BR=0.5, 0.75, and 1.0) and temperature ratio (TR=1.2, 1.6 and 1.9).  The computational study was based on conjugate CFD to simulate the experimental study with the flow and heat transfer in the gas phase modelled by steady RANS closed by the shear-stress transport (SST) turbulence model.  The experimental study was conducted by using the NETL Conjugate Aero-thermal Test Rig with a newly developed plenum configuration.  Measurements made include velocity and temperature profiles upstream and downstream of the film-cooling holes on the film-cooled side as well as temperature on surface of the plate on the hot and cold sides.  The computational study was validated by comparing computed results with those from measurements with BR = 0.75 and 1.0 and TR = 1.9.  Computational and experimental results are presented to show the effects of BR and TR on the flow structure and how that structure improves the effectiveness of film cooling with and without DVGs.

Presenting Author: Tom Shih Purdue University

Presenting Author Biography: Tom Shih is professor of aeronautics and astronautics at Purdue University. His research interests are fluid mechanics, heat transfer, CFD, gas turbine aerothermal, shock-wave.boundary interactions, aircraft icing, and thermal management of aerospace systems.

Authors:

Chien-Shing Lee Purdue University
Tom Shih Purdue University
Douglas Straub National Energy Technology Laboratory, US Department of Energy
Justin Weber National Energy Technology Laboratory, US Department of Energy
Edward Robey National Energy Technology Laboratory