The present study investigates heat/mass transfer for flow through perforated plates for application to combustor wall and turbine blade film cooling. The experiments are conducted for hole length-to-diameter ratios of 0.68 to 1.5, for hole pitch-to-diameter ratios of 1.5 and 3.0, for gap distance between two parallel perforated plates of 0 to 3 hole diameters, and for Reynolds numbers of 60 to 13,700. Local heat/mass transfer coefficients near and inside the cooling holes are obtained using a naphthalene sublimation technique. Detailed knowledge of the local transfer coefficients is essential to analyze thermal stress in turbine components. The results indicate that the heat/mass transfer coefficients inside the hole surface vary significantly due to flow separation and reattachment. The transfer coefficient near the reattachment point is about four and half times that for a fully developed circular tube flow. The heat/mass transfer coefficient on the leeward surface has the same order as that on the windward surface because of a strong recirculation flow between neighboring jets from the array of holes. For flow through two in-line layers, the transfer coefficient affected by the gap spacing is approximately 100% higher on the windward surface of the second wall and is about 20% lower on the inside hole surface than that with a single layer. The transfer coefficient on the leeward surface is not affected by upstream flow conditions due to probably strong recirculation in the wake flow.
- International Gas Turbine Institute
Total-Coverage Discrete Hole Wall Cooling
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Cho, HH, & Goldstein, RJ. "Total-Coverage Discrete Hole Wall Cooling." Proceedings of the ASME 1995 International Gas Turbine and Aeroengine Congress and Exposition. Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration. Houston, Texas, USA. June 5–8, 1995. V004T09A012. ASME. https://doi.org/10.1115/95-GT-012
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