An Investigation of Heat Transfer Coefficient and Film Cooling Effectiveness in a Transonic Turbine Cascade

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Date

1999-07-20

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Virginia Tech

Abstract

This study is an investigation of the film cooling effectiveness and heat transfer coefficient of a two-dimensional turbine rotor blade in a linear transonic cascade. Experiments were performed in Virginia Tech's Transonic Cascade Wind Tunnel with an exit Mach number 0f 1.2 and an exit Reynolds numbers of 5x106 to simulate real engine flow conditions. The freestream and coolant flows were maintained at a total temperature ratio of 2(+,-)0.4 and a total pressure ratio of 1.04. The freestream turbulence was approximately 1%. There are six rows of staggered, discrete cooling holes on and near the leading edge of the blade in a showerhead configuration. Cooled air was used as the coolant. Experiments were performed with and without film cooling on the surface of the blade. The heat transfer coefficient was found to increase with the addition of film cooling an average of 14% overall and to a maximum of 26% at the first gauge location. The average film cooling effectiveness along the chord-wise direction of the blade is 25%. Trends were found in both the uncooled and the film-cooled experiments that suggest either a transition from a laminar to a turbulent film regime or the existence of three-dimensionality in the flow-field over the gauges.

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Keywords

Heat--Transmission, transonic turbine, film cooling

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