Rib wall rotational flow gas film composite cooling device

Abstract

The invention provides a rib wall rotational flow gas film composite cooling device. The rib wall rotational flow gas film composite cooling device comprises a wall body, a plurality of disc-shaped rotational flow cavities are formed in the wall body in the cold air transverse flow direction, air film holes are formed between the edges of the disc-shaped rotational flow cavities and the outer wall face of the wall body, and inclined impact holes are formed between the edges of the disc-shaped rotational flow cavities and the inner wall face of the wall body. A plurality of turbulent flow ribs are arranged on the inner wall face of the wall body in the cold air transverse flow direction. On the basis of a ribbed channel, a composite cooling structure of rotational flow cooling and air film outflow is combined, efficient cooling of the turbine moving blade in a mid-chord area is achieved, and the capacity of the turbine blade for bearing higher heat loads is improved.

Description

Technical Field

[0001] The invention belongs to the field of gas turbine turbine blade cooling structures, and in particular relates to a rib wall swirl air film composite cooling device. Background Art

[0002] As the thermal efficiency of gas turbines gradually increases, the inlet temperature of the turbine is also increasing. At present, the inlet temperature of the turbine of advanced heavy-duty gas turbines has reached 1650℃, and the next generation of heavy-duty gas turbines is expected to reach more than 1700℃, which is far higher than the allowable temperature of the blade material. More complex and efficient cooling structures are also being continuously applied to turbine blade cooling to ensure the safe operation and long life of turbine blades.

[0003] In turbine blades, due to the influence of high-speed rotation, the internal cooling air channel in the mid-chord area of ​​the blade usually adopts a serpentine ribbed channel with transverse (blade span) ventilation. The spoiler ribs increase the heat exchange area in the channel, generate complex vortex structures, destroy the development of the flow boundary layer and the thermal boundary layer, and increase the flow turbulence, thereby enhancing the internal heat exchange performance. However, as the initial temperature of the gas continues to increase, this cooling method is difficult to meet the cooling needs of the next generation of turbine blades.

[0004] The swirl cooling structure has good thermal uniformity and strong heat exchange capacity. The swirl cavity uses the curvature wall to make the cooling fluid form a swirl motion close to the wall. The strong shear effect between the vortex and the wall can effectively enhance heat exchange and improve cooling performance.

[0005] Film cooling is an efficient cooling method and is widely used in turbine blades and moving blades. Film cooling opens a series of discrete film holes on the blade surface. The cooling medium is injected into the mainstream through the film holes and adheres to the wall under the pressure of high-temperature combustion gas. A low-temperature fluid covers the high-temperature surface of the turbine blade, thereby increasing the heat transfer resistance of the blade surface and effectively blocking the invasion of the high-temperature mainstream. Summary of the invention

[0006] The purpose of the present invention is to further improve the cooling efficiency of the mid-chord area of ​​a turbine rotor blade, and to provide a rib wall swirl air film composite cooling device for the internal ventilation form along the blade span direction.

[0007] A rib-wall swirl air film composite cooling device comprises a wall body; a plurality of disc-shaped swirl cavities are arranged in the wall body along the cross-flow direction of cold air, air film holes are opened between the edge of the disc-shaped swirl cavity and the outer wall surface of the wall body, and inclined impact holes are opened between the edge of the disc-shaped swirl cavity and the inner wall surface of the wall body; a plurality of spoiler ribs are arranged on the inner wall surface of the wall body along the cross-flow direction of cold air.

[0008] Furthermore, the disc-shaped swirl chamber is centrally arranged in the wall body along the wall thickness direction.

[0009] Furthermore, the axis of the air film hole forms an acute angle of no more than 45° with the outer wall surface of the wall body, and the direction of the axis is the same as the direction of the high-temperature mainstream.

[0010] Furthermore, the inlet edge of the air film hole is tangent to the edge of the disc-shaped swirl cavity.

[0011] Furthermore, the axis of the inclined impact hole forms an acute angle of no more than 45° with the inner wall surface of the wall body, and the direction of the axis is the same as the cross-flow direction of the cold air.

[0012] Furthermore, the inlet edge of the inclined impact hole is tangent to the edge of the disc-shaped swirl chamber.

[0013] Furthermore, the angle between the axis direction of the air film hole and the axis direction of the inclined impact hole is 270°; and the entrance of the air film hole is located on the back side of the inclined impact hole.

[0014] Furthermore, the spoiler ribs and the inclined impact hole inlets are alternately arranged along the cross-flow direction of the cold air and are located between the two spoiler ribs.

[0015] Furthermore, the wall thickness of the outer wall, the arrangement density of the swirl chambers and the number of spoiler ribs can be adjusted accordingly according to the heat load on the gas side and the structural strength.

[0016] The beneficial effects of the present invention are:

[0017] 1. In the composite cooling structure of the present invention, the inflow of the disc-shaped swirl cold air cavity adopts the form of inclined impact cooling. On the one hand, the heat exchange enhancement effect at the impact stagnation point is stronger, and the enhanced heat area formed by the inclined impact wall jet is larger. On the other hand, it provides sufficient jet momentum for the swirl motion close to the wall in the swirl cavity, which helps to enhance the vortex strength, thereby further enhancing the heat exchange capacity in the swirl cavity.

[0018] 2. The cold air is discharged from the disc-shaped swirl chamber of the present invention in the form of an air film. On the one hand, the suction effect of the air film holes can further enhance the circumferential swirl motion of the fluid in the swirl chamber, and the inlet of the air film holes is located on the back side of the inclined impact hole. In addition, the larger angle between the two is beneficial to the full development of the vortex motion in the swirl chamber. On the other hand, the outflow of the air film also forms a low-temperature fluid cover in the downstream area of ​​the cold air flow, thereby protecting the downstream area of ​​the blades.

[0019] 3. In the composite cooling structure of the present invention, the swirl cold air cavity allows the cold air to be closer to the wall surface. The smaller thermal conductivity resistance helps the swirl cooling structure to better improve the heat exchange capacity, and the enhanced convection in the air film hole further enhances the heat exchange.

[0020] 4. In the composite cooling structure of the present invention, after the cold air passes through the spoiler ribs to form a complex vortex system to enhance the heat exchange capacity of the inner wall, it enters the swirl cavity to further enhance the heat exchange, and finally forms an air film covering on the outer wall, realizing the multi-stage utilization of the cold air. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the positive triaxial side view of the present invention;

[0022] Figure 2 It is a positive triaxial side view of the arrangement relationship (fluid domain) of the internally connected cavities of the present invention;

[0023] Figure 3 is a side view of the present invention;

[0024] Figure 4 It is a bottom view of the present invention.

[0025] In the figure: 1. spoiler rib, 2. inclined impact hole, 3. disc-shaped swirl cavity, 4. air film hole, 5. wall. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings.

[0027] like Figure 1-Figure 4 As shown, a rib-wall swirl air film composite cooling device is provided, in which a plurality of disc-shaped swirl cavities 3 are arranged in the wall body 5 along the cross-flow direction of cold air, air film holes 4 are opened between the edge of the disc-shaped swirl cavity 3 and the outer wall surface of the wall body 5, and inclined impact holes 2 are opened between the edge of the disc-shaped swirl cavity 3 and the inner wall surface of the wall body 5; the inner wall surface of the wall body 5 is provided with a plurality of spoiler ribs 1 along the cross-flow direction of cold air.

[0028] In this embodiment, the disc-shaped swirl chamber 3 is arranged in the center of the wall body 5 along the wall thickness direction, so that the cold air is closer to the outer wall surface, reducing the heat conduction group and improving the heat exchange performance. The diameter of the swirl chamber 3 is not greater than 4 times the diameter of the air film hole 4, and the height of the swirl chamber 3 is the same as that of the air film hole 4 and the inclined impact hole 2, both of which are 1 times the aperture (the diameter of the air film hole 4 is the same as the diameter of the inclined impact hole 2).

[0029] In this embodiment, the axis of the air film hole 4 forms an acute angle of no more than 45° with the outer wall surface of the wall body 5, and the axis direction is the same as the high-temperature mainstream direction, so that the air film cold air can better adhere to the wall surface.

[0030] Furthermore, the inlet edge of the air film hole 4 is tangent to the edge of the disc-shaped swirl chamber 3 .

[0031] In this embodiment, the axis of the inclined impact hole 2 forms an acute angle of no more than 45° with the inner wall surface of the wall body 5 to achieve a larger impact jet coverage area, promote swirl motion in the disc-shaped swirl cavity 3, thereby enhancing heat exchange, and the axis direction is the same as the cross-flow direction of the cold air to facilitate the flow between the cross-flow of the cold air and the disc-shaped swirl cavity 3.

[0032] Furthermore, the inlet edge of the inclined impact hole 2 is tangent to the edge of the disc-shaped swirl chamber 3, so that the cold air swirl generated by the impact can better adhere to the side wall surface of the swirl chamber 3.

[0033] In this embodiment, the angle between the axial direction of the air film hole 4 and the axial direction of the inclined impact hole 2 is 270°, and the entrance of the air film hole 4 is located on the back side of the inclined impact hole 2 to avoid the air film hole 4 from sucking the fluid in the vortex chamber 3 prematurely, so as to fully develop the vortex motion in the vortex chamber.

[0034] See also Figure 1 The spoiler ribs 1 are rectangular spoiler ribs to increase the flow turbulence and destroy the development of the flow boundary layer and the thermal boundary layer, thereby enhancing the heat exchange performance of the inner wall surface of the wall body 5. The spoiler ribs 1 and the inlet of the inclined impact holes 2 are alternately arranged along the cross-flow direction of the cold air and are located between the two spoiler ribs 1.

[0035] Furthermore, the wall thickness of the outer wall 5, the arrangement density of the swirl chambers and the number of the spoiler ribs can be adjusted accordingly according to the heat load on the gas side and the structural strength.

[0036] The working process of the present invention is further described below to further demonstrate the working principle and advantages of the present invention:

[0037] The cooling medium enters through the cold air cross-flow channel, and is affected by the turbulent ribs on the inner wall to generate a complex vortex system, which improves the convection heat transfer coefficient of the inner wall. Then, a cold air jet is formed through the inclined impact hole and enters the disc-shaped swirl cavity, impacting the target surface and side wall of the swirl cavity, thereby enhancing the heat exchange. At the same time, a vortex is generated in the swirl cavity to further improve the heat exchange capacity. After the vortex flow is fully developed, it finally flows out through the air film hole, and a low-temperature air film is generated on the outer wall of the wall along the mainstream direction to cover and protect the downstream area.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rib wall swirl air film composite cooling device, characterized in that: It comprises a wall body (5); a plurality of disc-shaped swirl cavities (3) are arranged inside the wall body (5) along the cross-flow direction of cold air, an air film hole (4) is provided between the edge of the disc-shaped swirl cavity (3) and the outer wall surface of the wall body (5), and an inclined impact hole (2) is provided between the edge of the disc-shaped swirl cavity (3) and the inner wall surface of the wall body (5); a plurality of spoiler ribs (1) are arranged on the inner wall surface of the wall body (5) along the cross-flow direction of cold air.

2. The rib wall swirl air film composite cooling device according to claim 1, characterized in that: The disc-shaped swirl chamber (3) is arranged centrally in the wall body (5) along the wall thickness direction.

3. The rib wall swirl air film composite cooling device according to claim 1, characterized in that: The axis of the air film hole (4) forms an acute angle of no more than 45° with the outer wall surface of the wall body (5), and the direction of the axis is the same as the direction of the high-temperature mainstream.

4. The rib wall swirl air film composite cooling device according to claim 1, characterized in that: The inlet edge of the air film hole (4) is tangent to the edge of the disc-shaped swirl chamber (3).

5. The rib wall swirl air film composite cooling device according to claim 1, characterized in that: The axis of the inclined impact hole (2) forms an acute angle of no more than 45° with the inner wall surface of the wall body (5), and the direction of the axis is the same as the cross-flow direction of the cold air.

6. The rib wall swirl air film composite cooling device according to claim 1, characterized in that: The inlet edge of the inclined impact hole (2) is tangent to the edge of the disc-shaped swirl chamber (3).

7. The rib wall swirl air film composite cooling device according to claim 1, characterized in that: The angle between the axis direction of the air film hole (4) and the axis direction of the inclined impact hole (2) is 270°; the entrance of the air film hole (4) is located on the back side of the inclined impact hole (2).

8. The rib wall swirl air film composite cooling device according to claim 1, characterized in that: The spoiler ribs (1) and the inlets of the inclined impact holes (2) are arranged alternately along the cross-flow direction of the cold air and are located between the two spoiler ribs (1).

9. The rib wall swirl air film composite cooling device according to claim 1, characterized in that: The wall thickness of the outer wall (5), the arrangement density of the swirl chambers and the number of the spoiler ribs can be adjusted accordingly according to the heat load on the gas side and the structural strength.

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