Curvature steam turbine vane airfoil
First Claim
1. A steam turbine comprising:
- a) a stationary cylinder for containing a steam flow, and a rotor enclosed by said cylinder;
b) a row of blades attached to the periphery of said rotor; and
c) a row of vanes supported on said cylinder and disposed upstream of said row of blades, each of said vanes having an airfoil portion having leading and trailing edges and forming a suction surface and a pressure surface between said leading and trailing edges, said airfoil portion having a width in the axial direction and having a cross-sectional shape that, in conjunction with said trailing edge of an adjacent one of said vanes in said row, defines a gauging point on said suction surface, said pressure surface having a cross-sectional shape in at least one radial location along said airfoil that has a substantially flat portion that extends upstream from said trailing edge by a distance of at least approximately 40% of said airfoil axial width, said suction surface having a cross-sectional shape in said at least one radial location along said airfoil that has;
(i) a substantially flat first portion forming all of said suction surface that is downstream of said gauging point,(ii) a curved section portion upstream of said gauging point, said second portion having a first curvature,(iii) a second curvature along a third portion upstream of said second portion, said second curvature being less than said first curvature, and(iv) a third curvature along a fourth portion upstream of said third portion and ending at said leading edge, said third curvature being greater than said second curvature.
2 Assignments
0 Petitions
Accused Products
Abstract
A high performance steam turbine vane having a novel airfoil shape. The pressure surface of the airfoil has a substantially straight region proximate the trailing edge that provides the airfoil with adequate thickness to prevent distortion during forging. The novel shape on the suction surface is such that a first region of the suction surface downstream of the gauging point is essentially straight. Traveling in the upstream direction, the first region is followed by a second region that has a large amount of curvature. The second region is followed by a third region that has a lower curvature than the second region. The third region is followed by a fourth region of constantly increasing curvature that increases to a curvature greater than the curvature of the second region. The fourth region is followed by a fifth region, ending at the leading edge, of essentially constant large curvature that includes the maximum curvature throughout the suction surface.
51 Citations
17 Claims
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1. A steam turbine comprising:
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a) a stationary cylinder for containing a steam flow, and a rotor enclosed by said cylinder; b) a row of blades attached to the periphery of said rotor; and c) a row of vanes supported on said cylinder and disposed upstream of said row of blades, each of said vanes having an airfoil portion having leading and trailing edges and forming a suction surface and a pressure surface between said leading and trailing edges, said airfoil portion having a width in the axial direction and having a cross-sectional shape that, in conjunction with said trailing edge of an adjacent one of said vanes in said row, defines a gauging point on said suction surface, said pressure surface having a cross-sectional shape in at least one radial location along said airfoil that has a substantially flat portion that extends upstream from said trailing edge by a distance of at least approximately 40% of said airfoil axial width, said suction surface having a cross-sectional shape in said at least one radial location along said airfoil that has; (i) a substantially flat first portion forming all of said suction surface that is downstream of said gauging point, (ii) a curved section portion upstream of said gauging point, said second portion having a first curvature, (iii) a second curvature along a third portion upstream of said second portion, said second curvature being less than said first curvature, and (iv) a third curvature along a fourth portion upstream of said third portion and ending at said leading edge, said third curvature being greater than said second curvature. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A row of stationary vanes for a steam turbine, each of said vanes comprising an airfoil portion having leading and trailing edges and forming a suction surface and a pressure surface between said leading and trailing edges, said airfoil portion having a cross-sectional shape that, in conjunction with said trailing edge of an adjacent one of said vanes in said row, defines a gauging point on said suction side, said pressure surface having a cross-sectional shape in at least one radial location along said airfoil that has a substantially flat region proximate said trailing edge and a curved region upstream of said flat region, said flat region extending tangentially from said curved region, said suction surface having a cross-sectional shape in said at least one radial location along said airfoil that has:
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a) a substantially flat first portion forming all of said suction surface that is downstream of said gauging point; b) a first curvature along a second portion of said suction side upstream of said gauging point; c) a second curvature along a third portion of said suction surface upstream of said second portion, said second curvature being less than said first curvature; and d) a third curvature along a fourth portion of said suction surface upstream of said third portion, said third curvature being greater than said second curvature. - View Dependent Claims (9, 10, 11)
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12. A stationary vane for a steam turbine, comprising an airfoil portion having leading and trailing edges and forming a suction surface and a pressure surface between said leading and trailing edges, said airfoil having a width in the axial direction, and said suction surface having a cross-sectional shape in at least one radial location along said airfoil that has:
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a) a substantially downstream-most first portion that is substantially flat; b) a second portion immediately upstream of said first portion having a maximum curvature in the range of approximately 0.08 to 0.10 cm-1 ; c) a third portion immediately upstream of said second portion having a minimum curvature in the range of approximately 0.05 to 0.06 cm-1 ; and d) a fourth portion immediately upstream of said third portion and extending to said leading edge and having a maximum curvature in the range of approximately 0.15 to 0.17 cm-1. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification