Browsing by Subject "Gas turbine heat transfer."
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Item Experimental and numerical investigation of high temperature jet impingement for turbine cooling applications.(2011-05-12T15:42:00Z) Martin, Evan L.; Wright, Lesley Mae.; Engineering.; Baylor University. Dept. of Mechanical Engineering.Modern gas turbine engines commonly operate at temperatures above the melting point of the turbine’s blades and vanes. Internal and external cooling of the blades is required for sustained operation and prolonged engine life. Jet impingement, an aggressive form of cooling, is typically used in the airfoil leading edge which is exposed to extreme heat loads. A parametric study is used to experimentally and numerically investigate high temperature jet impingement in the blade leading edge. The effects of jet Reynolds number (Rejet), jet-to-target surface spacing (ℓ/d), jet-to-jet spacing (s/d), jet-to-target surface curvature (D/d), and jet temperature on stagnation Nusselt numbers are evaluated in a high temperature test apparatus. The facility is validated against correlations developed in previous studies. The experimental study is complimented with CFD simulations performed using commercially available software. Nusselt number results show strong dependence on Reynolds number and geometry yet little or no dependence on jet temperature.Item Experimental investigation of leading edge jet impingement with varying jet geometries and inlet supply conditions for turbine cooling applications.(2012-08-08) Jordan, C. Neil.; Wright, Lesley Mae.; Engineering.; Baylor University. Dept. of Mechanical Engineering.Jet impingement is often employed within the leading edge of modern gas turbine airfoils to combat the extreme heat loads incurred within this region. This experimental investigation employs a transient liquid crystal technique to obtain detailed Nusselt number distributions on a concave, cylindrical surface that models the leading edge of a turbine blade. The effect of hole shape, varying edge conditions at the jet orifice, as well as varying inlet crossflow conditions are investigated. Cylindrical and racetrack shaped jets with three inlet and exit conditions are investigated for each jet shape: a square edge, a partially filleted edge, and a fully filleted edge. Results show that racetrack shaped jets generally provide enhanced heat transfer when compared to the cylindrical holes. However, engine designers should be cautious when introducing edge fillets and inlet crossflow, as these modifications generally degrade the heat transfer from the leading edge target surface.