Browsing by Subject "Gas turbine cooling."
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Item An experimental investigation of round and racetrack shaped jets for leading edge region cooling of gas turbine blades.(2014-09-05) Harmon, Weston V.; Wright, Lesley Mae.; Mechanical Engineering.; Honeywell Aerospace.; Baylor University. Dept. of Mechanical Engineering.Jet impingement is often utilized in the leading edge of actively cooled turbine airfoils to protect the blades from the extreme heat loads encountered within the engine. This thesis will discuss two experimental investigations that employ a traditional, steady state, copper plate technique to obtain regionally averaged Nusselt numbers on a concave surface, which models the leading edge of a turbine blade. The first experiment will investigate the effect of jet shape, orifice edge condition, jet-to-jet spacing, and relative jet length. The effect of inlet supply condition will also be investigated by implementing a radial bypass. The second experiment investigates the effect of rotation on both round and racetrack shaped impinging jets. Results show that racetrack shaped jets generally outperform circular jets both in a stationary test section, and under rotating conditions. Further, the effects of non-square edge conditions and radial bypass prove to be detrimental to heat transfer.Item Numerical prediction and correlation of leading edge jet impingement with varying jet shapes and flow conditions for gas turbine cooling.(2013-09-24) Elston, Cassius A., III.; Wright, Lesley Mae.; Mechanical Engineering.; Honeywell Aerospace.; Baylor University. Dept. of Mechanical Engineering.To increase the core power of gas turbine engines, the combustion temperature is elevated above the metallurgical limits of the internal components. As a consequence, active cooling schemes are required to prevent the blades from melting. In this study, a numerical investigation of leading edge impingement cooling was performed. The effects of jet Reynolds number, jet-to-target surface spacing, jet-to-jet spacing, target surface curvature, and jet aspect ratio on the target surface Nusselt numbers were quantified. In all cases, the jets were equally spaced and had fully filleted edges. The numerical results were utilized to develop an empirical correlation for the surface average Nusselt number. The correlation enables engine designers to accurately predict the heat flux on the blade wall, as well as identify the optimal leading edge geometry to minimize the amount of cooling air required; thus, increasing the thermal efficiency of the gas turbine engine.