Abstract

To increase gas turbine cycle efficiency it requires higher turbine inlet temperatures. Multiple cooling mechanisms are used in order to ensure the survival of hot-gas-path components. Impingement cooling is one of the most prevalent methods due to its ability to remove heat over a localized area with a high local heat transfer coefficient. However,, the same level of high heat transfer cannot be uniformly maintained over a large surface due to degradation of downstream jets by cross-flow created by post impingement flow from upstream jets. In order to avoid jet degradation and hence to enhance overall heat transfer, this study focuses on use of U-shaped guide vane inserts surrounding downstream impingement jets. A multi-objective numerical optimization approach is performed to perfect the U-shape guide vane insert where heat transfer and pressure ratio are maximized for a given coolant flow. Three models are obtained from the Pareto optimal front and compared through experimental testing. Temperature Sensitive Paint (TSP) is used to experimentally obtain the local Heat Transfer distributions for an average jet Reynolds number ranging from 75,000 to 150,000. Results show that utilizing U-shaped guided vane inserts can protect against cross-flow and thus enhance overall heat transfer at the target surface.

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