Experimental Investigations of Microchannel Cooling within a Nozzle Guide Vane Trailing Edge Configuration
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Date
2017-05
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The Ohio State University
Abstract
Improving component cooling to sustain higher gas turbine inlet temperatures is a widely-studied subject to improve engine efficiency. From advances in additive manufacturing technology, the use of microchannel cooling is possible within turbine components and appears advantageous due to significant heat transfer benefit within a small packaging and the ability to provide targeted cooling [1]. Although microchannel usage at relevant engine conditions has been characterized in prior research [16,18], application into a trailing edge geometry and direct comparison to current trailing edge cooling technologies has yet to be explored. The purpose of this study is to characterize the heat transfer performance of near surface microchannel cooling within a trailing edge configuration for direct comparison to current cooling technologies. The current cooling technologies tested were ribbed turbulators and a pin fin array. Utilizing bulk flow analysis and the Thermal Inertia HTC technique, effective surface heat transfer rates were determined and compared for the three cooling configurations within the same trailing edge geometry. Cooling performance parameters evaluated within testing include Nusselt number, and pressure drop. Near surface microchannel cooling shows potential for improvement to surface heat transfer at higher Reynolds numbers. Although there is a large pressure drop within the microchannel, utilizing a denser array of microchannels would reduce the pressure drop across the test article and could produce an overall improvement to cooling efficiency. This increase in cooling efficiency would require less mass flow to be utilized for component cooling, increasing the mass flow for power generation. Near surface microchannel cooling proves promising to produce efficiency increases in future gas turbine engines.
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Keywords
Microchannel, Turbine Cooling, Trailing Edge, Heat Transfer