Twin side-by-side dimpled film cooling hole and turbine blade
By designing twin parallel exhaust film holes with recesses, the problems of small coverage area of single circular holes and high processing difficulty of traditional bifurcated holes are solved, achieving a larger coverage area and higher cooling efficiency, which is suitable for turbine blades of gas turbines and aero engines.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENYANG AEROSPACE UNIVERSITY
- Filing Date
- 2023-01-30
- Publication Date
- 2026-06-02
AI Technical Summary
In existing film cooling technologies, single circular holes have a small span of coverage area and limited cooling effect, while traditional bifurcated holes are difficult to process and are prone to metal fatigue.
A twin parallel air film vent with a recess is designed, including twin vents and a recess structure at the outlet end. The recess is surrounded by a hump-shaped wall and a concave wall, which improves the spanwise coverage and vortex resistance of the air film and reduces the processing difficulty.
It enhances the wall adhesion effect of the cooling jet, increases the lateral coverage area of the air film, reduces the processing difficulty, and is suitable for turbine blade cooling systems of gas turbines and aero engines.
Smart Images
Figure CN115977745B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of gas turbine and aero-engine technology, and particularly to a twin parallel exhaust film orifice with recesses and a turbine blade. Background Technology
[0002] According to thermodynamic principles, increasing the turbine inlet temperature is an effective way to increase engine thrust and improve engine efficiency. However, excessively high temperatures can cause creep or even melting of the turbine blade material, seriously threatening engine safety. Therefore, taking effective cooling measures is crucial. The application of film cooling technology not only isolates the high-temperature combustion gas from the turbine wall, reducing direct contact between the gas and the wall, but also allows for direct heat exchange with the blade wall, lowering the blade's own temperature. As an effective method to ensure turbine safety, it is widely adopted by engineers.
[0003] In the development of film cooling technology, the single circular orifice, as the most classic orifice type, has been used to this day. However, due to its overly concentrated jet and small spanwise coverage area, the film air mixes with the mainstream air at high blowing ratios and detaches from the blade surface, thus limiting its cooling effect. Traditional bifurcated orifices form an acute angle at the connection with the main orifice, where the momentum of the cooling jet is large, which can easily cause metal fatigue and is also difficult to process.
[0004] Therefore, in order to solve the problems of poor spanwise coverage and low cooling effect of single circular holes as well as the problems of traditional bifurcated holes, it is necessary to improve the air film hole structure to meet higher design requirements. Summary of the Invention
[0005] To address the problems existing in the prior art, this invention provides a twin parallel air film vent with recesses and turbine blades. It is simple in design and easy to process, and has greatly improved anti-vortex properties and lateral coverage area. It can accumulate cooling jets and enhance the flow direction and wall adhesion effect of the air film.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows:
[0007] A twin parallel exhaust membrane orifice with a recess includes twin orifices and a recess structure disposed at the outlet end of the twin orifices;
[0008] The twin apertures comprise two single circular apertures whose radial portions intersect;
[0009] The recessed structure is a circumferentially closed structure formed by a camel-hump-shaped wall and a concave wall.
[0010] Furthermore, the concave wall surface includes a middle wall surface and side walls perpendicularly disposed at both ends of the middle wall surface. The middle wall surface is perpendicular to the intersection line A, and the side walls are parallel to the intersection line A. The intersection line A is the projection of the center line of the twin holes onto the plane where the exit end of the twin holes is located.
[0011] Furthermore, the walls of the two single circular holes intersect at a front intersection line and a rear intersection line. The intersection of the front intersection line with the plane where the exit end of the twin holes is located is the front intersection point, and the intersection of the rear intersection line with the plane where the exit end of the twin holes is located is the rear intersection point.
[0012] Furthermore, the hump-shaped wall surface includes a rear convex arc wall surface and two front convex arc wall surfaces symmetrically arranged on both sides of the rear convex arc wall surface. The front convex arc wall surfaces and the concave wall surface are connected by a spline curve transition.
[0013] Furthermore, the angle between the straight line passing through the center of the convex arc wall and the intersection point and the intersection line A is α, where α is 50° to 60°.
[0014] Furthermore, the diameter of the single circular hole is D; the depth H of the recessed structure is 0.5D to 1D, and the width is L1; the vertical distance between the rear intersection point and the middle wall is L2; the distance between the side wall and the tangent of the adjacent twin holes is L3, where L3 is 0.25D to 1D; the distance between the tangent at the vertex of the convex arc wall and the tangent at the leading edge of the exit end of the twin holes is L4, where L4 is 0.75D to 1D; the center distance L5 between the two single circular holes that make up the twin holes is 0.5D to 0.9D; the hole length L of the twin holes is 2D to 8D; the diameter of the convex arc wall is 0.5D, and the diameter of the rear convex arc wall is 0.75D.
[0015] Furthermore, the plane where the twin-hole outlet end is located is coplanar with the bottom surface of the pit structure, the plane where the twin-hole outlet end is located is parallel to the top surface of the pit structure, and both the hump-shaped wall and the concave wall are perpendicular to the plane where the twin-hole outlet end is located.
[0016] Furthermore, the twin aperture and recess structure as a whole is a symmetrical structure about the intersection line A.
[0017] Furthermore, the centerline of the twin apertures is arranged at an angle to the main flow, and the angle between the centerline of the twin apertures and the direction of the main flow is 15° to 60°.
[0018] A turbine blade includes a turbine blade body, wherein the turbine blade body is provided with a plurality of twin parallel exhaust film holes with recesses.
[0019] The beneficial effects of this invention are:
[0020] 1) The twin parallel air film cooling structure with recesses of the present invention is applied to the cooling system of turbine blades of gas turbines and aero engines. It can effectively increase the coverage of the air film, effectively suppress the rise of airflow under high blowing ratio, and is easy to process.
[0021] 2) Compared with traditional round holes, the twin parallel air film holes with recesses of the present invention have improved anti-vortex performance and significantly increased lateral coverage area compared with single round holes. Compared with traditional bifurcated holes, the special recessed structure of the twin recessed holes can accumulate cooling jets to a certain extent. Under the same incident angle, the cooling jets enhance the flow direction and wall adhesion effect of the air film, which is also true under high blowing ratio. Moreover, compared with bifurcated holes and other irregular holes, the twin recessed holes are much easier to process and have excellent application prospects.
[0022] 3) The twin bore of the present invention is composed of two intersecting cylindrical bores with a center distance L5 of 0.5D to 0.9D, which increases its lateral area while considering the feasibility of processing; the concave contour is provided with a hump-shaped wall, including two forward convex arc walls and one backward convex arc wall. The diameter of the forward convex arc wall is 0.5D and the diameter of the backward convex arc wall is 0.75D. After the cold air is ejected through the twin bore, part of it hits the concave wall and flows to both sides, flowing out of the concave from both sides. Part of it crosses the concave and flows out from the middle, forming a cooling air film on the outer wall, which plays a role in cooling the hot end components of the turbine.
[0023] Other features and advantages of the present invention will be described in detail in part in the following detailed description. Attached Figure Description
[0024] Figure 1 This is a perspective view of the twin parallel exhaust membrane pores with recesses provided in an embodiment of the present invention;
[0025] Figure 2 This is a top view of the twin parallel exhaust film holes with recesses provided in an embodiment of the present invention;
[0026] Figure 3 This is a side cross-sectional view of a twin parallel exhaust film vent with recesses provided in an embodiment of the present invention. Detailed Implementation
[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0028] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0029] In order to solve the problems existing in the current technology, such as Figures 1 to 3 As shown, the present invention provides a twin parallel exhaust membrane orifice with a recess, including twin orifices and a recess structure disposed at the outlet end of the twin orifices;
[0030] A twin-hole consists of two intersecting single-circular holes with radial portions;
[0031] The pit structure is a circumferentially closed structure formed by camel-hump-shaped walls and concave walls.
[0032] This embodiment uses a recessed twin-tube parallel film cooling orifice for turbine blades, which is an irregularly shaped orifice composed of twin tubes and a recessed structure. The recessed structure is connected to the outlet end of the twin tubes. Two overlapping single circular holes form the twin tubes, which are cylindrical. The recessed structure is located above the outlet end of the twin tubes, surrounding it; the twin tubes are essentially embedded holes within the recessed structure. The recessed structure consists of two parts, front and rear, with the line connecting the centers of the two single circular holes at the outlet end of the twin tubes serving as the dividing line. The front part has a hump-shaped wall, and the rear part has a concave wall. Compared to traditional single-circle film cooling orifices, this embodiment of a recessed twin-tube parallel film cooling orifice significantly improves air cooling efficiency and spanwise efficiency. Furthermore, compared to some irregularly shaped orifices, the manufacturing difficulty is greatly reduced, meeting higher design requirements.
[0033] The concave wall includes a middle wall and side walls perpendicularly disposed at both ends of the middle wall. The middle wall is perpendicular to the intersection line A, and the side walls are parallel to the intersection line A. The intersection line A is the projection of the center line of the twin holes onto the plane where the exit end of the twin holes is located. Both side walls of the concave wall are parallel to the intersection line A.
[0034] The walls of the two single circular holes intersect at the front intersection line and the rear intersection line. The intersection of the front intersection line with the plane where the exit end of the twin holes is located is the front intersection point, and the intersection of the rear intersection line with the plane where the exit end of the twin holes is located is the rear intersection point.
[0035] The hump-shaped wall includes a rear convex arc wall and two front convex arc walls symmetrically arranged on both sides of the rear convex arc wall. The front convex arc walls and the concave wall are connected by a spline curve transition. Specifically, the hump-shaped wall includes two front convex arc walls and one rear convex arc wall. The two front convex arc walls are symmetrically arranged on the left and right sides of the rear convex arc wall.
[0036] like Figure 2 As shown, the angle between the straight line passing through the center of the front convex arc wall and the front intersection point and the intersection line A is α, where α is 50° to 60°. The larger the angle α is, the wider the span of the air film formed. The center of the rear convex arc wall (in the plane where the twin-hole outlet end is located) is collinear with the intersection line A.
[0037] like Figure 2 and Figure 3 As shown, the diameter of the single circular hole is D; the depth H of the recessed structure is 0.5D to 1D, and the width is L1; the vertical distance between the rear intersection point and the intermediate wall is L2; the distance between the side wall and the tangent of the adjacent twin holes is L3, where L3 is 0.25D to 1D; the distance between the tangent at the vertex of the convex arc wall and the tangent at the leading edge of the twin hole outlet is L4, where L4 is 0.75D to 1D; the center distance L5 between the two single circular holes forming the twin holes is 0.5D to 0.9D; the hole length L of the twin holes is 2D to 8D; the diameter of the convex arc wall is 0.5D, and the diameter of the rear convex arc wall is 0.75D. In this embodiment, the tangent of the twin holes adjacent to the side wall is parallel to the intersection line A, and the tangent at the vertex of the convex arc wall and the tangent at the leading edge of the twin hole outlet are both parallel to the intermediate wall.
[0038] The plane at the outlet end of the twin apertures is coplanar with the bottom surface of the recessed structure, and the plane at the outlet end of the twin apertures is parallel to the top surface of the recessed structure. That is, the top surface of the recessed structure is flush with the turbine blade wall, and both the hump-shaped wall and the concave wall are perpendicular to the plane at the outlet end of the twin apertures.
[0039] The twin aperture and recessed structure are symmetrical about the intersection line A.
[0040] The centerlines of the twin apertures are arranged at an angle to the main flow, with the angle between the centerlines of the twin apertures and the direction of the main flow being 15° to 60°.
[0041] The present invention also provides a turbine blade, including a turbine blade body, wherein the turbine blade body is provided with a plurality of twin parallel air film perforations with recesses. The turbine blade body is a turbine blade in the prior art; this embodiment only improves the air film perforation structure.
[0042] Example
[0043] The diameter of the single circular hole is D = 4 mm; the hole length is L = 10 mm; the center distance is L5 = 3.5 mm; the perpendicular distance between the tangent at the vertex of the convex arc wall and the tangent at the exit end of the twin holes is L4 = 2.96 mm; the distance between the rear intersection point and the middle wall is L2 = 4.66 mm; the distance between the side wall and the tangent of the adjacent twin holes is L3 = 3 mm; the width of the recessed structure is L1 = 13.5 mm; the depth of the recessed structure is H = 4 mm; the angle α between the center of the convex arc wall and the center line of the twin holes is 53°.
[0044] The twin parallel air film orifice with recesses used in this embodiment increases the lateral expansion of its outlet end and the stability of the air film compared to a single circular orifice. At the same time, the recessed structure allows the cooling jet to undergo secondary expansion, effectively reducing the momentum of the cooling jet and suppressing its rise under high blowing ratios. The convex arc wall can guide the cooling jet to both sides, thereby generating beneficial vortices. Through the combination of several structures, the entire structure can play a greater role.
[0045] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims
1. A twin-tube parallel exhaust film vent with recesses, characterized in that, Includes a twin aperture and a recessed structure disposed at the outlet end of the twin aperture; The twin apertures comprise two single circular apertures whose radial portions intersect; The recessed structure is a circumferentially closed structure formed by a camel-hump-shaped wall and a concave wall; The concave wall surface includes a middle wall surface and side walls perpendicularly disposed at both ends of the middle wall surface. The middle wall surface is perpendicular to the intersection line A, and the side walls are parallel to the intersection line A. The intersection line A is the projection of the center line of the twin holes onto the plane where the exit end of the twin holes is located. The walls of the two single circular holes intersect at a front intersection line and a rear intersection line. The intersection of the front intersection line with the plane where the exit end of the twin holes is located is the front intersection point, and the intersection of the rear intersection line with the plane where the exit end of the twin holes is located is the rear intersection point. The hump-shaped wall includes a rear convex arc wall and two front convex arc walls symmetrically arranged on both sides of the rear convex arc wall. The front convex arc walls and the concave wall are connected by a spline curve transition. The diameter of the single circular hole is D; the depth H of the recessed structure is 0.5D~1D, and the width is L1; the vertical distance between the rear intersection point and the middle wall is L2; the distance between the side wall and the tangent of the adjacent twin holes is L3, where L3 is 0.25D~1D; the distance between the tangent at the vertex of the convex arc wall and the tangent at the leading edge of the exit end of the twin holes is L4, where L4 is 0.75D~1D; the center distance L5 between the two single circular holes that make up the twin holes is 0.5D~0.9D; the hole length L of the twin holes is 2D~8D; the diameter of the convex arc wall is 0.5D, and the diameter of the rear convex arc wall is 0.75D.
2. The twin parallel exhaust film vent with recesses according to claim 1, characterized in that, The angle between the straight line passing through the center of the convex arc wall and the intersection point and the intersection line A is α, where α is 50°~60°.
3. The twin parallel exhaust film vent with recesses according to claim 2, characterized in that, The plane containing the twin-hole outlet end is coplanar with the bottom surface of the recessed structure, the plane containing the twin-hole outlet end is parallel to the top surface of the recessed structure, and both the hump-shaped wall and the concave wall are perpendicular to the plane containing the twin-hole outlet end.
4. The twin parallel exhaust film pores with recesses according to claim 2, characterized in that, The twin aperture and recess structure are symmetrical about the intersection line A.
5. The twin parallel exhaust film vent with recesses according to claim 2, characterized in that, The centerline of the twin apertures is inclined to the main stream, and the angle between the centerline of the twin apertures and the direction of the main stream is 15°~60°.
6. A turbine blade, comprising a turbine blade body, characterized in that, The turbine blade body is provided with a plurality of twin parallel exhaust film holes with pits as described in claim 1.