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Non-Axisymmetric Endwall Contouring |
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Project Funded by: Pratt & Whitney |
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Researcher: Steve Lynch |
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Several methods have been investigated to control complex 3-D flows, known as secondary flows, which develop at the junction of an airfoil and the endwall in a gas turbine. Secondary flows consist of vortical structures that generate aerodynamic (flow efficiency) losses, as well as increase rate of heat transfer from the hot combustion gases to the turbine component. Fillets at the leading edge of the airfoil, such as the design shown in Figure 1, have been shown to reduce or eliminate the horseshoe vortex at the airfoil-endwall junction. Non-axisymmetric contouring of the endwall has also been shown to be effective at reducing aerodynamic losses in a turbine stage. Non-axisymmetric contouring consists of “waves” in the endwall shape, which manipulate the development of the passage vortex as it progresses through the passage. |
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In this study, we will be examining the effect of non-axisymmetric endwall contouring on airfoil endwall heat transfer and film cooling effectiveness. This study will provide a more complete understanding of both the aerodynamic and thermal benefit of non-axisymmetric contouring in the high temperature environment of a gas turbine airfoil. |
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Figure 1. The complex vortical motions of the secondary flows at the airfoil-endwall junction (a) are eliminated when an asymmetric leading-edge fillet (b) is placed at the junction. |