CN216518159U - Gas film cooling structure for gas turbine blade - Google Patents

Abstract

The utility model discloses a gas film cooling structure for gas turbine turbine blades, which comprises gas film holes arranged on the turbine blades and end walls and a protruding structure upstream of the gas film holes. The axis of the outlet parallel to the main flow direction is the axis of symmetry, and the section of the raised structure is composed of two smooth transition arcs.

and

constitute. The utility model improves the air film cooling efficiency of the turbine blade without introducing additional aerodynamic losses by arranging a convex structure whose section is composed of two smoothly connected circular arcs on the upstream of the air film hole outlet.

Description

A film cooling structure for gas turbine turbine blades

technical field

The utility model belongs to the technical field of gas turbine blade cooling, in particular to a gas film cooling structure for gas turbine turbine blades, which can provide an efficient gas film cooling effect for gas turbine turbine blades.

Background technique

At present, the initial temperature of the turbine of heavy-duty gas turbines continues to increase, which puts forward higher requirements for blade design. The temperature of the gas in the turbine has far exceeded the allowable temperature of the blade material, and the increase in the gas temperature also leads to an increase in the thermal load and thermal stress of the blade, and the increase in the initial temperature of the turbine inlet is much faster than that through material technology. The speed of the allowable temperature of the material, so the gas turbine cooling technology has become an extremely important part of the gas turbine technology.

Air film cooling is a commonly used cooling method in turbine blades. Cold air is injected into the mainstream through the air film holes or slot structures on the surface of the turbine blades, and a layer of air film is formed on the outer surface of the blade, which separates the metal blades from the high temperature. The main flow is isolated and blended with the high temperature main flow to reduce its temperature so that the high temperature components are within the temperature tolerance range. Film cooling has always been a hot issue in the design of turbine blade cooling structures because it involves the mixing and interaction of cold air and the mainstream, and the flow field structure is complex and directly related to the working conditions of the turbine.

According to the analysis of the flow field structure upstream and downstream of the air film hole outlet, it is found that due to the mutual mixing of the mainstream and the cold air, a pair of counter-rotating vortices (kidney-shaped vortex pair) will be formed downstream of the air film hole outlet, as shown in Figure 1. By weakening the strength of the kidney-shaped vortex pairs, the film cooling effect can be significantly improved. The protruding structure is arranged upstream of the air film hole, and by changing the shape and height of the protrusion, the effect of the cold air adhering to the wall surface and the lateral coverage area of the cold air can be increased. A positive secondary flow kidney vortex is formed near the outlet, thereby weakening the strength of the cooling airflow kidney vortex pair and improving the cooling efficiency of the air film holes. Therefore, upstream structures of gas film holes with different shapes are proposed, but although the existing structures can effectively improve the cooling efficiency of the gas film, some structures are difficult to process and costly, and are not easy to use in actual turbines, and some structures have a greater impact on the mainstream. bring additional aerodynamic losses.

Utility model content

Aiming at the deficiencies of the prior art, the utility model provides a film cooling structure for gas turbine turbine blades. Film cooling efficiency of turbine blades.

The utility model adopts the following technical scheme to realize:

与

构成。A gas film cooling structure for gas turbine turbine blades, comprising gas film holes arranged on the turbine blades and the end wall and a protruding structure upstream of the gas film holes, the protruding structure is parallel to the main flow from the outlet of the gas film holes The axis of the flow direction is the axis of symmetry, and the section of the raised structure consists of two smooth transition arcs.

and

constitute.

以O₁为圆心，r₁为半径，该圆弧右侧与壁面交点记为A，左侧端点记为B。A further improvement of the utility model is that: the first arc of the raised structure section is

Taking O ₁ as the center and r ₁ as the radius, the intersection point on the right side of the arc with the wall is marked as A, and the left end point is marked as B.

的圆心O₁与下游气膜孔前端距离S的取值范围为0.5D～3D，圆心O₁与壁面垂直距离h的取值范围为0.5D～2D，半径r₁的取值范围为1.2h～2.2h。The further improvement of the utility model is: the arc

The value range of the distance S between the center O1 _of the circle and the front end of the downstream gas film hole is 0.5D～3D, the value range of the vertical distance h between the circle center O1 and the wall is 0.5D～2D, and the value range _of the radius _r1 is 1.2h ~2.2h.

左侧端点B与圆心O₁的连线与壁面交于D点，BD与垂直于壁面方向的夹角为θ，θ的取值范围为0°～30°。The further improvement of the utility model is: the arc

_The line connecting the left end point B and the circle center O1 intersects the wall at point D, the angle between BD and the direction perpendicular to the wall is θ, and the value of θ ranges from 0° to 30°.

以位于BD连线上的点O₂为圆心，以r₂为半径，作圆弧与壁面相交于C点。A further improvement of the utility model is that: the second arc of the convex section is

Taking the point O ₂ on the connecting line of BD as the center and r ₂ as the radius, draw an arc to intersect the wall at point C.

的圆心O₂位于BD连线的中点，半径r₂的值为BO₂的长度。A further improvement of the utility model is that: the second arc of the convex section is

The center _O2 of the circle is located at the midpoint of the line connecting BD, and the value of the radius _r2 is the length of _BO2 .

A further improvement of the present invention is that: the width of the protruding structure in the spanwise direction is W, and the value of W ranges from 0.5D to 1.2D.

The further improvement of the utility model is that: the air film hole outlet has a spanwise width D, and the inclination angle α between the cooling airflow and the main flow direction is 0-90°.

The utility model at least has the following beneficial technical effects:

The utility model provides a gas film cooling structure for gas turbine turbine blades. By arranging a convex structure with a cross section composed of two smoothly connected arcs on the upstream of the gas film hole outlet, without introducing additional aerodynamic losses It can improve the film cooling efficiency of the turbine blades.

The advantage of the utility model is that, different from other methods in the past, the structure is simple, the effect is obvious, and the implementation is convenient, and at the same time, due to the small size of the protrusion and the smooth transition, the additional aerodynamic loss can be ignored.

Description of drawings

Figure 1 is a schematic diagram of the formation of vortex pairs downstream of the gas film holes.

FIG. 2 is a three-dimensional schematic diagram of the utility model.

FIG. 3 is a top view of the utility model.

Figure 4 is a side view of the utility model.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present utility model more clearly understood, the present utility model will be further described in detail below with reference to the accompanying drawings and examples.

The utility model provides a gas film cooling structure for gas turbine turbine blades, which comprises gas film holes arranged on the turbine blades and end walls and a protruding structure upstream of the gas film holes.

The spanwise width of the air film hole is D, and the angle between it and the wall is α. In this embodiment, the spanwise width D is 1 mm, and the included angle α is 30°.

与

构成。凸起剖面的第一段圆弧

以O₁为圆心，r₁为半径，该圆弧右侧与壁面交点记为A，左侧端点记为B。The convex structure takes the axis of the air film hole outlet parallel to the main flow direction as the axis of symmetry, and the section is composed of two smooth transition arcs.

and

constitute. The first arc of the raised profile

Taking O ₁ as the center and r ₁ as the radius, the intersection point on the right side of the arc with the wall is marked as A, and the left end point is marked as B.

的圆心O₁与下游气膜孔前端距离S的取值范围为0.5D～3D，本实施实例中优选S为2.5mm。arc

The value range of the distance S between the center O1 _of the circle and the front end of the downstream gas film hole is 0.5D to 3D, and in this embodiment, S is preferably 2.5mm.

The value range of the vertical distance h between the center O ₁ and the wall surface is 0.5D to 2D, and in this embodiment, h is preferably 1 mm.

The value range of the radius r ₁ is 1.2h˜2.2h, and in this embodiment, r ₁ is preferably 1.5 mm.

左侧端点B与圆心O₁的连线与壁面交于D点，BD与垂直于壁面方向的夹角为θ，θ的取值范围为0°～30°，本实施实例中优选θ为15°。arc

_The connecting line between the left end point B and the center O1 intersects the wall at point D, the angle between BD and the direction perpendicular to the wall is θ, and the value of θ ranges from 0° to 30°. In this embodiment, the preferred θ is 15 °.

以位于BD连线上的中点O₂为圆心，以BO₂为半径，作圆弧与壁面相交于C点。The second arc of the raised profile

Taking the midpoint O ₂ on the connecting line of BD as the center, and taking BO ₂ as the radius, draw an arc to intersect the wall at point C.

The width of the protruding structure in the spanwise direction is W, and the value of W ranges from 0.5D to 1.2D. In this embodiment, W is preferably 0.8 mm.

In this embodiment, by arranging a convex structure composed of two smoothly connected arcs upstream of the air film hole outlet, the air film cooling efficiency of the turbine blade is improved without introducing additional aerodynamic losses.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall include within the scope of the present invention.

Claims (8)

1. The gas film cooling structure for the turbine blade of the gas turbine is characterized by comprising gas film holes arranged on the turbine blade and the end wall and a convex structure at the upstream of the gas film holes, wherein the convex structure takes the axis of the outlet of the gas film holes parallel to the incoming flow direction of a main flow as a symmetrical axis, and the section of the convex structure is formed by two sections of arc in smooth transition

And

and (4) forming.

2. The film cooling structure for a turbine blade of a gas turbine according to claim 1, wherein: the first section of arc of the section of the convex structure

With O₁As a center of circle, r₁The intersection point of the right side of the arc and the wall surface is denoted as A, and the left end point is denoted as B.

3. The film cooling structure for a turbine blade of a gas turbine according to claim 2, wherein: circular arc

Center of circle O of₁The distance S from the front end of the downstream air film hole ranges from 0.5D to 3D, and the center of the circle is O₁The vertical distance h from the wall surface ranges from 0.5D to 2D, and the radius r₁The value range of (A) is 1.2 h-2.2 h.

4. The film cooling structure for a turbine blade of a gas turbine according to claim 2, wherein: circular arc

Left end point B and circle center O₁The connecting line of (A) intersects with the wall surface at a point D, the included angle between the BD and the direction vertical to the wall surface is theta, and the value range of theta is 0-30 degrees.

5. The film cooling structure for a turbine blade of a gas turbine according to claim 2, wherein: the second section of arc of the section of the convex structure

To be located at point O on the BD line₂As the center of circle, in r₂The radius is defined as the radius, and the arc intersects the wall surface at the point C.

6. The film cooling structure for a turbine blade of a gas turbine according to claim 5, wherein: the second section of arc of the section of the convex structure

Center of circle O of₂At the midpoint of the BD line, radius r₂Has a value of BO₂Length of (d).

7. The film cooling structure for a turbine blade of a gas turbine according to claim 1, wherein: the width of the protruding structure in the spanwise direction is W, and the value range of W is 0.5D-1.2D.

8. The film cooling structure for a turbine blade of a gas turbine according to claim 1, wherein: the outlet of the film hole has a width D in the spanwise direction, and the inclination angle alpha between the cooling airflow and the main flow direction is 0-90 degrees.

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