JP4930276B2 - Internal cooling structure for high temperature parts - Google Patents

Description

  The present invention relates to an internal surface cooling structure for high-temperature parts such as moving blades and stationary blades in an aeronautical or industrial gas turbine.

High temperature parts such as moving blades and stationary blades in aero or industrial gas turbines are exposed to high temperature gas (for example, 1000 ° C or higher) during operation. In some cases, a high temperature component is cooled from the inside by flowing a cooling gas (for example, cooling air).
Thus, many studies have been conducted in the past to understand the performance of such an internal cooling structure and enhance its cooling performance (for example, Patent Documents 1 and 2 and Non-Patent Documents 1 and 2).

  As shown in FIG. 7, the inner surface cooling structure of Patent Document 1 includes at least one wall 53 having an inner portion 51 and an outer portion 52, and a plurality of flow paths 54 extending between the inner portion and the outer portion of the wall. It comprises a plurality of pins 56 forming the mesh cooling structure 55 and a plurality of turbulent flow generating portions 57 provided on at least one of the inner part and the outer part.

  As shown in FIG. 8, the blade cooling structure of Patent Document 2 is provided between a back side wall portion 66 that forms a suction side surface of a stationary blade 64 and an abdominal side wall portion 67 that forms a pressure side surface. The pin fin 61 which transmits the heat of the part 66 and the abdominal side wall part 67 to the cooling air Y, and the rib 62 which is provided in the back side wall part inner surface 69 and is provided radially from the pin fin 61 and promotes cooling efficiency are provided. .

Non-Patent Document 1 is a research report on heat transfer in a flow path having dimples (concave portions) and convex portions on an opposing surface.
Non-Patent Document 2 is a research report on heat transfer of a mesh cooling structure having dimples (concave portions) and convex portions (corners, circles).

US Pat. No. 6,984,102, “HOT GAS PATH COMPONENT WITH MESH AND TURBULATED COOOLING” Japanese Unexamined Patent Publication No. 2006-242050, “Glass Turbine Blade Cooling Structure”

Gazi I.I. Mahmood and others, “Heat Transfer in a Channel with Dimpls and Propulsion on Opposite Walls”, Journal of Thermotransics and Heat Transforms. 15, no. 3, 2001 Ronald S. Bunker and others, “IN-WALL NETWORK (MESH) COOLING AUGMENTATION OF GAS TURBINE AIRFILLS”, Proceedings of ASME Turbo Expo 2004, 2004

As described above, the conventional inner surface cooling structure has a heat transfer member that directly connects the high temperature side and the low temperature side in order to transfer heat from the high temperature side to the low temperature side, or to transfer heat from both to the inside ( In the above example, the pin 18 and the pin fin 41 are used. However, because of this, there are few cavities inside the high-temperature parts, making it difficult to reduce the weight.
In addition, the trailing edge of the blades (moving blades and stationary blades) is a portion where the temperature is high among the blade surfaces, and high cooling performance is required, but because the thickness is thin and heated from both sides with high-temperature gas, A cooling wall cannot be provided inside. For this reason, conventionally, cooling enhancement by promoting turbulent flow is performed with pin fins or ribs, and the flow rate of cooling air is determined under the condition that the temperature of this portion is kept below the allowable metal value. Therefore, in order to reduce the cooling air flow rate more than before, it is necessary to apply a structure having a higher cooling effect to the part, and research on a high-performance cooling structure has been actively conducted.

  The present invention has been developed to solve the above-described problems. That is, the object of the present invention is to effectively cool a thin wall portion such as the trailing edge of the wing, there are many hollow portions inside, and the weight can be reduced. An object of the present invention is to provide an internal surface cooling structure for a high-temperature component capable of reducing the amount.

According to the present invention, an inner surface cooling structure of a high-temperature component that cools the inner surface of a high-temperature component whose outer surface is heated with a high-temperature gas with a cooling gas lower in temperature than the high-temperature gas,
A pair or a plurality of pairs of inner surfaces facing each other with a gap therebetween and through which the cooling gas flows;
A heat transfer facilitating member provided on each inner surface and arranged to increase the heat transfer rate ,
The heat transfer promotion member is composed of dimples, bumps, and ribs provided on each inner surface,
The dimples are arranged at a constant pitch in the cooling gas flow direction and in a direction perpendicular thereto,
The bumps are arranged at a constant pitch in the flow direction and in a direction perpendicular to the flow direction in a staggered arrangement with respect to the dimples,
The rib extends in a direction perpendicular to the flow direction and is connected between the bumps.
One dimple and the other bump on the inner surfaces facing each other are aligned, or are aligned within ½ pitch in the flow direction and the direction orthogonal thereto,
The bump has a truncated conical shape, and has a bottom diameter larger than the top diameter and a height less than 1/2 of the gap between the inner surfaces. .

  According to the above configuration of the present invention, the heat transfer promoting member is disposed on the inner surface of one or more pairs facing each other with a gap therebetween and through which the cooling gas flows, so that the heat transfer rate is increased. And the heat transfer coefficient between each inner surface can be increased.

Moreover, this heat transfer promotion member is composed of dimples, bumps and ribs, and various cooling structures are used in combination at a constant pitch, so that high cooling performance can be exhibited over the entire inner surface.
Further, since heat transfer members (for example, pins) that directly connect the inner surfaces facing each other are not used, there are many hollow portions inside the high-temperature component, and the weight can be reduced.
Further, the structure in which one dimple and the other bump on the inner surfaces facing each other are aligned or aligned within a ½ pitch in the flow direction and the direction perpendicular thereto can not only cause the cooling gas to flow along the inner surface. Since it has a flow component orthogonal to the inner surface, film cooling and impingement cooling can be used together, and the heat transfer rate can be further increased.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is a view showing an inner surface of a high temperature component constituting an inner surface cooling structure according to the present invention, FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. 3 is a sectional view taken along line BB in FIG.
The inner surface 10 of the high-temperature component constituting the present invention has dimples 12, bumps 14 and ribs 16 on its surface as heat transfer promoting members.
The dimples 12 are concave portions, each having a constant pitch in the flow direction of the cooling gas 1 (cooling air in this example) (the left-right direction in FIGS. 1 and 2) and the direction perpendicular thereto (up-down direction in FIGS. 1 and 2). They are arranged at p1 and p2. The cooling gas 1 is not limited to cooling air, and may be a cooling gas having a temperature lower than that of the high temperature gas.
The bumps 14 are protrusions, and are arranged in a staggered manner with respect to the dimples 12 at a constant pitch p1 and p2 in the flow direction of the cooling air 1 and in the direction perpendicular thereto.
The ribs 16 extend in a direction orthogonal to the flow direction of the cooling air 1 and are connected between the bumps 14.

In this example, the dimple 12 is a recess having a diameter d, a depth h, and a curved surface diameter D. In the example described later, h = 0.167d, D = 1.667d, p1 = 1.667d, p2 = 1. .667d.
The bump 14 has a truncated conical shape having a bottom diameter d1, a top diameter d2, and a height h1, and in the example described later, d1 = d, d2 = 0.733d, h1 = 0.133d, p1 = 1.667d, p2 = 1.667d.
The rib 16 is a rectangular bar-shaped member having a height h2 that connects the bumps 14, and in the example described later, h2 = 0.0833d.
In addition, this invention is not limited to these dimensions, It can change arbitrarily. Further, in this example, the bumps 14 are arranged in a staggered manner with a deviation of ½ pitch with respect to the dimple 12, but the present invention is not limited to this, and may be arranged with a deviation other than ½ pitch.

FIG. 4 is a view showing a first embodiment of the inner surface cooling structure of the present invention. In this figure, (A) is a cross-sectional view along the center position of the dimple 12 in the flow direction of the cooling air, and (B) is a cross-sectional view along the center position of the bump 14.
FIG. 5 is a perspective view showing the shape of the air flow path in the configuration of FIG.

4, the inner surface cooling structure of FIG. 5, and set the Reynolds number Re of the flow channel to about ^104, as a result of the Nusselt number Nu between the inner surfaces and the fluid was analyzed using CFD, approximately as compared with the case of the flat plate 1 A value of .32 times was obtained.
Therefore, it was confirmed that the inner surface cooling structure of FIGS. 4 and 5 has a higher heat transfer performance than at least the flat plates.

FIG. 6 is a view showing a second embodiment of the inner surface cooling structure of the present invention. In this example, one dimple 12 and the other bump 14 on the inner surfaces facing each other are aligned at the same position over the entire surface.
In this example, since the positions of the dimple 12 and the bump 14 coincide with each other, the cooling air not only flows along the inner surface but also has a flow component orthogonal to the inner surface. Therefore, a cooling structure similar to film cooling or impingement cooling can be used in combination, and the heat transfer coefficient can be further increased than in the first embodiment.
The present invention is not limited to this configuration, and the positions of the dimples 12 and the bumps 14 may be aligned within a ½ pitch in the flow direction and the direction orthogonal thereto.

  According to the above-described configuration of the present invention, the heat transfer promotion member (in order to increase the heat transfer rate on the pair or the plurality of pairs of inner surfaces 10 through which the cooling gas 1 (cooling air) flows with the gap H therebetween. Since the dimples 12, the bumps 14, and the ribs 16) are arranged, the heat transfer coefficient between the cooling air 1 and each inner surface 10 can be increased.

Further, the heat transfer promoting member is constituted by the dimples 12, the bumps 14, and the ribs 16, and various cooling structures are used in combination with the constant pitches p1 and p2, respectively, so that high cooling performance can be exhibited over the entire surface.
In addition, since heat transfer members (for example, pins) that directly connect the inner surfaces 10 facing each other are not used, there are many hollow portions inside the high-temperature component, and the weight can be reduced.
Further, the cooling air flows along the inner surface by the configuration in which one dimple 12 and the other bump 14 of the inner surface 10 facing each other are aligned or aligned within ½ pitch in the flow direction and the direction orthogonal thereto. In addition, since it has a flow component orthogonal to the inner surface, film cooling and impingement cooling can be used together, and the heat transfer rate can be further increased.

In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.
For example, unlike the example described above, the following configuration may be used.
(1) The bump may have a smaller diameter than the dimple.
(2) The ratio of the upper base diameter (top diameter) to the lower base diameter (bottom diameter) of the bump, the height ratio of the rib to the bump, the ratio of the gap between the bump and the two plates, the ratio of the dimple diameter to the pitch Are not limited to the examples described above.
(3) An intermediate arrangement between the first embodiment and the second embodiment may be used. That is, in the method of making the two cooling structure components face each other, the shift amount in the direction perpendicular to the flow may be a structure other than 0 pitch or 0.5 pitch.

It is a figure which shows the member inner surface which comprises the inner surface cooling structure by this invention. It is an enlarged view of the A section of FIG. It is BB sectional drawing of FIG. It is a figure which shows 1st Embodiment of the inner surface cooling structure of this invention. It is a perspective view which shows the shape of the air flow path in the structure of FIG. It is a figure which shows 1st Embodiment of the inner surface cooling structure of this invention. It is a schematic diagram of the internal surface cooling structure of patent document 1. FIG. It is a schematic diagram of the blade | wing cooling structure of patent document 2.

Explanation of symbols

1 cooling gas (cooling air), 10 inner surface,
12 dimples, 14 bumps,
16 Ribs

Claims (3)

An inner surface cooling structure for a high-temperature component that cools an inner surface of a high-temperature component whose outer surface is heated by a high-temperature gas with a cooling gas having a lower temperature than the high-temperature gas
A pair or a plurality of pairs of inner surfaces facing each other with a gap therebetween and through which the cooling gas flows;
A heat transfer facilitating member provided on each inner surface and arranged to increase the heat transfer rate ,
The heat transfer promotion member is composed of dimples, bumps, and ribs provided on each inner surface,
The dimples are arranged at a constant pitch in the cooling gas flow direction and in a direction perpendicular thereto,
The bumps are arranged at a constant pitch in the flow direction and in a direction perpendicular to the flow direction in a staggered arrangement with respect to the dimples,
The rib extends in a direction perpendicular to the flow direction and is connected between the bumps.
One dimple and the other bump on the inner surfaces facing each other are aligned, or are aligned within ½ pitch in the flow direction and the direction orthogonal thereto,
The bump has a frustoconical shape, and has a bottom diameter larger than the top diameter and a height less than half of the gap between the inner surfaces. 2. The high-temperature component according to claim 1, wherein the dimple is a concave portion having a spherical inner surface, the diameter is equal to or larger than the bottom diameter of the bump, and the depth is lower than the height of the bump. Internal cooling structure. The internal rib cooling structure for a high-temperature component according to claim 1, wherein the rib is a rectangular bar-shaped member, and the height thereof is lower than the height of the bump.

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