Date of Award

3-2025

Document Type

Thesis

Degree Name

Master of Science in Astronautical Engineering

Department

Department of Aeronautics and Astronautics

First Advisor

James L. Rutledge, PhD

Abstract

Film cooling experimentation aims to improve the cooling performance while minimizing the amount of coolant flow redirected from the compressor. The coolant flow that is used for film cooling reduces the maximum thrust any gas turbine engine can produce. Finding creative ways to improve cooling performance without increasing the amount of coolant used, like phantom cooling, is essential for the gas turbine industry to improve engine performance while increasing turbine components’ lifespan. Phantom cooling refers to any secondary cooling effect that propagates downstream from its original cooling application to cool subsequent turbine components. Phantom cooling is actively gaining more attention in the gas turbine community because it increases the cooling effect without extracting more coolant flow from the compressor. The present study investigates predicting the combined cooling effect of upstream phantom cooling and downstream leading-edge film cooling using a variety of superposition techniques. Prior to the present study, no work has investigated predicting the combined phantom cooling and leading-edge film cooling effect. First, the classical Muska adiabatic effectiveness technique with modifications to predict the combined cooling effect with multiple coolant temperatures is applied to predict the combined phantom and leading-edge film cooling adiabatic effectiveness. Second, a recently published superposition technique known as the resistance ratio technique is also applied to predict the combined phantom and leading-edge film cooling overall effectiveness. Lastly, the classical Muska adiabatic effectiveness superposition technique is modified to predict the combined phantom and leading-edge film cooling overall effectiveness. The results of the present study demonstrate that the Muska technique, combined with modern principles discovered by investigating the resistance ratio technique’s utility, can predict the combined phantom and leading-edge film cooling overall and adiabatic effectiveness. The resistance ratio method predicted the combined phantom and leading-edge film cooling overall effectiveness, but not with the same level of accuracy used to predict the combined cooling effect of other cooling sources. Comparing the superposition error between the Muska and resistance ratio techniques demonstrates that the Muska technique is more accurate to predict the combined overall effectiveness for the present geometry than the resistance ratio technique. The Muska and resistance ratio superposition techniques should be approached with caution; the present study demonstrates that each technique is useful, but the accuracy of each technique is highly dependent on the type of coolant sources each technique is applied to.

AFIT Designator

AFIT-ENY-MS-25-M-141

DTIC Accession Number

AD1356388

Comments

An embargo was observed for posting this thesis.

Distribution A: Approved for Public Release, Distribution Unlimited.

PA clearance case 88ABW-2025-0424

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