JP2016510380A - Component having cooling channel with hourglass cross section and corresponding turbine airfoil component - Google Patents

Abstract

The cooling channels (36, 36B, 63-66) cool the inner surface (48, 50) of the outer wall (41, 43) of the component (20, 60). The inner side surfaces (52, 54) of the channel converge on the waist (W2) to form an hourglass-shaped transverse profile (46). The inner surfaces (48, 50) have fins (44) aligned with the cooling body flow (22). The fin has a transverse profile (56A, 56B) that is highest in the middle of the width of the inner surface (48, 50). The turbulator (92) is provided on the side of the channel and pushes the flow of the cooling body towards the inner surface (48, 50). Each turbulator (92) has a peak (97) that defines the waist of the cooling channel. Each turbulator has a convex upstream side (93). These elements increase the flow of the cooling body at the corner (C) of the channel to cool the outer walls (41, 43) more uniformly and efficiently.

Description

  This application is a continuation-in-part of US Application No. 12 / 985,553 (Attorney Docket No. 2010P12609US) filed January 6, 2011, which is incorporated herein by reference. Is done.

STATEMENT REGARDING FEDERALLY SPONSORED DEVELOPMENT The development of the present invention was supported in part by contract number DE-FC26-05NT42644 awarded by the US Department of Energy. Accordingly, the US government may have certain rights in the invention.

BACKGROUND OF THE INVENTION Components (parts) in the hot gas flow path of a gas turbine often have cooling channels. Cooling efficacy is important to minimize thermal stresses in these components, and cooling efficiency is important to minimize the amount of air that is diverted from the compressor for cooling. Film cooling supplies a film of cooling air from the internal cooling channel through the holes and onto the outer surface of the component. Film cooling is inefficient because a large amount of cooling air is required. Thus, film cooling has been selectively used in combination with other techniques. In the technique of impingement cooling, a perforated baffle is separated from the surface in order to generate an impinging jet of cooling air against the surface. Serpentine cooling channels are provided in turbine components including airfoils such as blades and vanes. The present invention increases efficacy and efficiency in the cooling channel.

  The present invention is described in the following description in connection with the drawings described below.

FIG. 1 is a cross-sectional side view of a turbine blade having a cooling channel. FIG. 2 is a cross-sectional view of the trailing edge of the airfoil taken at line 2-2 of FIG. 1 with cooling channels illustrating aspects of the present invention. FIG. 3 is a transverse profile of a cooling channel according to an aspect of the present invention. FIG. 4 is a cross-sectional view of the cooling channel near one side wall. FIG. 5 is a cross-sectional view of a cooling channel in a tapered component. FIG. 6 is a transverse cross-sectional view of a turbine airfoil having an hourglass shaped cooling channel. FIG. 7 shows the process of forming a ceramic core for a mold for an hourglass shaped cooling channel. FIG. 8 shows a transverse cross-sectional view of an hourglass-shaped cooling channel having a converging side defined by a peaked turbulator. FIG. 9 shows the embodiment of FIG. 8 combined with fins on the near wall inner surface. FIG. 10 is a view taken along line 10-10 of FIG. 8 showing a peaked turbulator having a convex upstream side.

Detailed Description of the Invention FIG. 1 is a cross-sectional view of a turbine blade 20 having a leading edge 21 and a trailing edge 23. Cooling air 22 from the turbine compressor enters from the inlet 24 of the blade root 26 and flows through channels 28, 29, 30, 31 in the blade. A part of the cooling body exits from the film cooling hole 32. The trailing edge portion TE of the blade has a turbulator pin 34 and an outlet channel 36. Each arrow 22 indicates the flow direction of the entire cooling body at the location of this arrow, which means the dominant or average flow direction at this point.

  FIG. 2 is a cross-sectional view of the trailing edge portion TE of the turbine airfoil taken along line 2-2 of FIG. The trailing edge portion has a first outer surface 40 and a second outer surface 42 on the suction side wall 41 and the pressure side wall 43 of the airfoil. According to aspects of the present invention, the cooling channel 36 has fins 44 on the inner surface 48 of the outer wall 41 and the inner surface 50 of the outer wall 43. These inner surfaces 48 and 50 are referred to in the art as “near wall inner surfaces” and refer to the inner surface of the cooling channel closest to the outer surface to be cooled. The spacing G between the channels creates an imbalance in cooling efficiency and uniformity. The inventors have recognized that because the cooling channel corner C is closest to the spacing G, increasing the cooling rate at these corners improves cooling efficiency, efficiency and uniformity. One way to achieve this preferential cooling is to provide an hourglass-shaped channel profile in which the channel sides 52 and 54 are connected to the first inner surface 48 and the second inner surface 50. Form a waist that is narrower than the width of each. This waist functions to increase the flow resistance in the center of the channel and pushes the cooling body towards the corner of the channel. Although the cooling body flow in the center of the channel does not contact the heat transfer surface, the flow in the corner functions to remove heat, so the present invention is effective in increasing the efficiency of cooling.

  FIG. 3 is a transverse cross-sectional profile 46 of the cooling channel that is shaped to efficiently cool two opposing external surfaces. This channel is the trailing edge channel 36 or any other cooling channel such as channels 29 and 30 in FIG. This channel has two opposing near-wall inner surfaces 48 and 50 that are parallel to the respective outer surfaces 40 and 42 of FIG. As used herein, “parallel” refers to a portion of the near wall inner surface closest to the outer surface that does not take into account the fins 44. This channel has widths W1 and W3 at the near-wall inner surfaces 48 and 50. The two inner sides 52 and 54 are tapered from the sides of the inner surfaces 48 and 50 toward each other and define a minimum channel width W2 or waist at the sides. The inner surface widths W1 and W3 are larger than the waist width W2, so the channel profile 46 has an hourglass shape formed by the convex surfaces of the side surfaces 52 and 54. This shape increases the coolant flow 25 towards the corner C of the channel. The direction of the overall flow of the cooling body is perpendicular to the page in this figure. The arrows 25 indicate the direction of increasing flow of the profile 46 as compared to channels that do not have an hourglass shape and / or channels that do not have fins described below.

  Fins 44 are provided on the inner surfaces 48 and 50. These fins are aligned in an overall flow direction 22 (FIG. 1) perpendicular to the plane of FIG. Where fins are provided, the fins have a height that follows a convex profile such as 56A or 56B, which is the largest in the middle of the width of the near wall inner surface 48 and / or 50. Give fin height H. These fins 44 increase the surface area of the near wall inner surfaces 48 and 50 as well as increase the flow 25 at corner C. A relatively high central fin reduces flow to the center, while a relatively low distal fin facilitates flow 25 in corner C. The combination of the convex sides 52, 54 and the convex fin height profiles 56A, 56B provide a synergistic effect of concentrating cooling towards the corner C of the channel.

  The dimensions of the channel profile 46 are selected using known engineering methods. The ratios shown are given by way of example only. Since ratios are a relevant aspect illustrated in the drawings, the following length units are dimensionless and are sized proportionally in any unit of measurement. In one embodiment, the relative dimensions are B = 1.00, D = 0.05, H = 0.20, W1 = 1.00, W2 = 0.60. In this example, the side taper angle A = −30 °. Herein, the negative taper angle A of the sides 52 and 54 in the profile 46 is such that the sides converge towards each other and towards an intermediate position between the inner surfaces 48 and 50. As shown, the waist W2 is formed. In some embodiments, the taper angle A is in the range of -1 ° to -30 °. The waist width W2 is determined by the taper angle. Alternatively, in certain embodiments, W2 is 80% or less, or 65% or less of one or both of the near wall widths W1 and W3. One or more ratios and / or dimensions depend on the length of the cooling channel. For example, dimension B varies with the thickness of the airfoil. The widths W1 and W3 of the two inner surfaces 48 and 50 may be different from each other in some embodiments. In this case, the waist W2 is narrower than each of the widths W1 and W3.

  FIG. 4 shows a cooling channel 36B configured to cool a single exterior surface 40 or 42. FIG. The cooling channel 36B uses the concept of fins and taper angles of the cooling channel 36 described above. The near wall inner surface width W1 is greater than the minimum channel width W2 due to the tapered inner side surfaces 52 and 54. The fins 44 are provided on the near wall inner surface 48 and have a height profile that is convex at the center of the width W1 of the near wall inner surface. Such a cooling channel 36B is used, for example, in a relatively thick portion of the trailing edge portion TE of the airfoil, rather than a relatively thin portion of the trailing edge portion TE where the cooling profile 46 of FIG. 3 is used. . The transverse cross-sectional profile of this embodiment is trapezoidal, where the near wall inner surface 48 defines its longest side.

  FIG. 5 shows that the outer surfaces 40 and 42 are not parallel in the transverse cross section of the channel 36. Near wall inner surfaces 48 and 50 are parallel to outer surfaces 40 and 42.

  FIG. 6 shows a transverse cross section of a turbine airfoil 60 having hourglass shaped spanwise cooling channels 63, 64, 65 and 66. As used herein, “span direction” means that the channel is oriented in a direction between the radially inner end and the radially outer end of the airfoil. “Radial direction” is the direction relative to the axis of rotation of the turbine. For example, in FIG. 1, channels 28, 29, 30 and 31 are spanning channels. These channels optionally have fins 44 as described above with respect to FIG.

  FIG. 7 illustrates the process of forming ceramic cores 74 and 75 for the airfoil mold. These cores are chemically removed after casting the airfoil 60. A flexible die 84A, 84B, 85A, 85B or a die having a flexible liner is used to form the cores 74 and 75 of the ceramic compact, the cores 74, 75 of the ceramic compact being Is sufficiently stiff to pull elastically in the 89 direction beyond the intervening point 91. Such techniques are described, for example, by Mikro Systems Inc. of Charlotteville, Virginia. U.S. Pat. Nos. 7,141,812 and 7,410,606 and 7,411,204, assigned to U.S. Pat. For example, even a small negative taper angle, such as -1 ° to -3 °, is significant and useful for cooling efficiency compared to the positive taper angle required for conventional rigid die removal. .

  FIG. 8 shows a transverse cross-sectional view of an hourglass-shaped cooling channel 65 having converging sides 52 and 54 defined by a turbulator 92. Each turbulator has a peak 97 in the central portion of the turbulator that defines the waist of the cooling channel. The turbulator sides 52 and 54 have the above-mentioned range, or in particular, a taper range of -2 ° to -5 ° (shown is -5 °). The turbulator 92 may be replaced with surfaces 95, 96 that are flat (as shown) or have a positive taper (not shown).

  FIG. 9 shows the embodiment of FIG. 8 with fins 44 having the profile described above combined with near wall inner surfaces 48 and 50.

  FIG. 10 is a view taken along line 10-10 of FIG. 8 and shows a peaked turbulator 92 having a convex upstream side 93 and a linear downstream side 94. The convex upstream side 93 pushes the stream 22 toward the corner C. The straight downstream side 94 facilitates pulling the dies 84A, 84B, 85A, 85B of FIG. 7 straight and perpendicular to the cores 74,75. Alternatively, the downstream side 94 of the turbulator may be convex, for example parallel to the upstream side 93 (not shown).

  The embodiment of FIGS. 8-10 is manufactured using the cost effective process of FIG. The turbulator 92 concentrates the flow of the cooling body toward the near wall inner surfaces 48 and 50 and toward the corner C. The turbulator 92 slows the flow 22 around, while concentrating the flow 22 toward the inner surfaces 48 and 50, where the ribs 44 transfer heat from the outer surfaces 40, 42 and cause the flow 22 to flow. The combination feature shown in FIG. 9 is particularly effective and efficient because it increases towards corner C.

  The hourglass shaped channels of the present invention are useful in any near wall cooling application, such as vanes, blades, shrouds, and possibly gas turbine combustors and transition ducts. These increase the uniformity of cooling, particularly in a series of channels parallel to parallel flow or alternating meandering flow. The channels of the present invention are formed by known manufacturing techniques, for example, by casting an airfoil on a positive ceramic core that is chemically removed after casting.

  An advantage of the present invention is that the distal corner C near the channel wall removes more heat than a conventional cooling channel for a given cooling body flow rate. This improves the effectiveness, efficiency and uniformity of cooling by overcoming the tendency of slower flowing cooling bodies at the corners. The increased corner cooling helps to compensate for the cooling of the spacing G between the channels. The present invention also increases heat transfer from the major surfaces 40, 42 to be cooled by the use of fins 44.

  While various embodiments of the invention have been shown and described herein, it is obvious that such embodiments are provided for purposes of illustration only. Many variations, modifications and substitutions may be made without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.

Claims (19)

A component with an internal cooling channel,
The internal cooling channel is
A first inner surface of the first outer wall of the component and a second inner surface of the second outer wall of the component;
A first side surface and a second side surface extending between the first inner surface and the second inner surface;
The transverse cross-section of the internal cooling channel has an hourglass-shaped profile, wherein the first side surface and the second side surface are directed toward each other, the first inner surface and Tapered to a waist that is narrower than the respective width of the second inner surface;
A component wherein the overall direction of flow of the cooling body in the internal cooling channel is perpendicular to the hourglass-shaped profile.   The component of claim 1, wherein the first inner surface and the second inner surface are parallel to respective first and second portions of an outer surface of the respective outer wall.   The component of claim 1, wherein the first outer wall and the second outer wall are respectively a pressure side and a suction side of a turbine airfoil.   The component according to claim 1, wherein the waist has a width of 80% or less of a width of at least one of the first inner surface and the second inner surface.   Each of the first side surface and the second side surface has a taper angle in the profile, the taper angle being relative to a straight line between each corresponding end of the two side surfaces. The component of claim 1, wherein the component is at least −1 ° toward the waist.   A plurality of parallel fins having a transverse height profile, wherein the transverse height profile is convex over a width of at least one of the first inner surface and the second inner surface; The component of claim 1, wherein the plurality of parallel fins are oriented in a direction of flow of the cooling body.   Each of the first side surface and the second side surface further includes a plurality of turbulators, and the plurality of turbulators push the cooling body toward the first inner surface and the second inner surface, The component of claim 1, wherein a peak in a central portion of each turbulator defines the waist of the internal cooling channel.   The component of claim 7, wherein each turbulator has a convex upstream side.   The component of claim 7, wherein each turbulator comprises a convex upstream side and a linear downstream side. A plurality of parallel fins in each of the first inner surface and the second inner surface oriented in the direction of flow of the cooling body, wherein adjacent peaks of the plurality of fins are transverse to each other; A connected height profile includes a plurality of parallel fins that are convex across the width of each of the first inner surface and the second inner surface;
A plurality of turbulators on each of the first side surface and the second side surface, each turbulator having a peak at a convex upstream side and a central portion of the turbulator defining the waist of the cooling channel; The component according to claim 1, further comprising: a plurality of turbulators. A turbine airfoil component comprising a cooling body outlet channel at a trailing edge portion,
Two internal side surfaces in which the cooling body outlet channel is between a first wall near inner surface and a second wall near inner surface, and the first wall near inner surface and the second wall near inner surface And a plurality of fins on each of the first wall vicinity inner surface and the second wall vicinity inner surface,
The first near-wall inner surface and the second near-wall inner surface are parallel to the respective first and second outer surfaces of the trailing edge portion;
The two inner side surfaces converge to a waist located at a midpoint between the first near wall inner surface and the second near wall inner surface to create an hourglass-shaped transverse profile of the cooling body outlet channel. Forming,
The plurality of fins are aligned in the overall flow direction of the cooling body outlet channel, and the plurality of fins have a convex height profile across the width of the inner surface near each wall;
Turbine airfoil component.   Each of the two inner side surfaces further includes a plurality of turbulators, and the plurality of turbulators flow the cooling body toward the inner surface near the first wall and the inner surface near the second wall. The turbine airfoil component of claim 11, wherein peaks that are extruded and in the middle portion of each turbulator define the waist of the cooling channel.   The turbine airfoil component of claim 12, wherein each turbulator has a convex upstream side.   The turbine airfoil component of claim 12, wherein each turbulator has a convex upstream side and a linear downstream side.   Each of the two inner side surfaces further comprises a plurality of turbulators, each turbulator further comprising a convex upstream side and a peak at an intermediate portion of the turbulator defining the waist of the cooling channel. The turbine airfoil component of claim 11. A component comprising a cooling channel,
The cooling channel is
A first inner surface parallel to the first outer surface of the component;
A tapered transverse cross-sectional profile that is widened at the first inner surface and narrowed away from the first inner surface;
A plurality of parallel fins having a transverse height profile, wherein the transverse height profile is convex across the width of the first inner surface, and the plurality of parallel fins are A plurality of parallel fins oriented in the direction of flow of the cooling body of the channel;
The cooling channel functions to extrude a flow of cooling body in the cooling channel toward the corner of the cooling channel. A second inner surface parallel to the second outer surface of the component;
A first inner side surface and a second inner side surface extending between the first inner surface and the second inner surface;
A plurality of turbulators on each of the first inner side surface and the second inner side surface of the cooling channel, wherein the plurality of turbulators flow the cooling body between the first inner surface and the first inner surface; The peak in the middle portion of each turbulator defines the waist of the cooling channel, the waist being the width of either the first inner surface or the second inner surface 17. The component of claim 16, further comprising a plurality of turbulators that are narrower.   The component of claim 17, wherein each turbulator has a convex upstream side.   The component of claim 17, wherein each turbulator has a convex upstream side and a linear downstream side.

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