Session: 12-12 Computational Techniques

Paper Number: 78244

78244 - Film Cooling Hole Shape Effects on Turbine Blade Heat Transfer – Part I: Computational Comparison to Experiment 

Gas turbines generate highly unsteady flow fields, which are further complicated by turbine cooling. Film cooling technology development has historically been dependent on flat plate experimental and computational research, which often have difficulty translating to turbine domains. To help explain disconnects between flat plate experiments and turbine operation, this study performs computational research, grounded with experimental measurements, examining the film cooling performance of several different hole shapes on rotating turbine blades. Midspan experimental pressure and heat transfer data are used to evaluate the accuracy and usefulness of computations. Steady and unsteady computational models are both compared to experimental data, and results indicate significant model improvements are achieved with unsteady RANS simulations.

Round, fan, and advanced anti-vortex cooling hole geometries are incorporated into experimental hardware and computational models, and the film cooling performances of each hole type are compared at a constant coolant mass flow rate to determine the benefits of advanced film cooling shapes. Shaped film cooling holes are observed to benefit film cooling coverage on the blade surface, as indicated by stronger film effectiveness traces on the blade. Both the fan and advanced shaped film cooling holes generate stronger cooling jet cores that remain close to the blade wall on the pressure surface, suction surface, and near the leading edge. Advance shaped holes provide increased lateral spread that provides additional resistance to jet lift-off. Additionally, the contoured diffuser of the advanced hole generates resistance to radial migration on the pressure surface.

The results of this study help identify benefits of using shaped film cooling on the turbine blade as well as the mechanisms generating the cooling benefits. This will help designers to weigh the manufacturing costs of shaped film cooling holes as well as identify areas of the blade where shaped film cooling is needed and where it is not. Additionally, this study observes significant improvements in blade heat transfer predictions through unsteady treatment alone, indicating better computational agreement can be achieved by leveraging lower-cost RANS simulation tools.

Presenting Author: Spencer Sperling The Ohio State University

Presenting Author Biography: Bio to be provided later

Authors:

Spencer Sperling The Ohio State University
Louis Christensen The Ohio State University
Randall Mathison The Ohio State University
Hakan Aksoy Honeywell Aerospace
Jong Liu Honeywell Aerospace
Jeremy Nickol Honeywell Aerospace