Bird belly bionic structure of low-resistance cooling unit, low-resistance cooling unit and cooling flow channel

Abstract

The invention belongs to the technical field of internal cooling of aero-engine turbine blades, and particularly relates to a bird belly bionic structure of a low-resistance cooling unit, the low-resistance cooling unit and a cooling runner. The bionic structure comprises a first section, a second section, a third section, a fourth section and a fifth section which are integrally formed; the first section, the second section, the third section, the fourth section and the fifth section are sequentially arranged in the fluid flowing direction, and the first section is located at the fluid inflow end; the side faces of the first section and the second section form a smooth-transition inwards-concave curved surface, the side faces of the third section, the fourth section and the fifth section form a smooth-transition outwards-convex curved surface, and the inwards-concave curved surface and the outwards-convex curved surface are in smooth transition. By adopting a bionic structure, the flow resistance is reduced while the heat exchange area is increased and the contact between gas and the heat exchange surface is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of internal cooling technology for aero-engine turbine blades, and particularly relates to a bird-belly biomimetic structure for a low-resistance cooling unit, a low-resistance cooling unit, and a cooling flow channel. Background Technology

[0002] Turbine blades are subjected to loads such as high temperature and high speed of combustion gas, making them a core component of aero engines. The lifespan of turbine blades directly affects the service life of aero engines.

[0003] Currently, blades made of high-temperature alloys are prone to creep and ablation at the high temperatures of combustion gases without the support of cooling technology, leading to blade thermal failure. However, excessive use of cooling gas reduces the turbine's ability to extract power from the high-temperature combustion gases.

[0004] Internal cooling technology, as one of the core technologies of blade cooling, requires the cooling structure used to minimize the flow resistance of the cooling air while maximizing the efficiency of cooling air utilization. However, existing cooling structures have low cooling efficiency and high flow resistance.

[0005] Bionic structures, having undergone long-term evolution in nature, can bring improvements in certain aspects. The falcon is one of the fastest-flying birds in nature, especially when swooping down to hunt. Its wings gradually approach its body, and at its fastest speed, the wings are close to its sides, forming a spindle-like shape on its belly, resulting in lower drag.

[0006] We utilize the biomimetic shape of a falcon's belly as a cooling enhancement structure for the internal cooling channel wall of turbine blades, which can improve cooling performance while reducing flow resistance. Summary of the Invention

[0007] The purpose of this invention is to provide a bird's belly biomimetic structure for a low-resistance cooling unit, a low-resistance cooling unit, and a cooling channel to solve the above-mentioned problems.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] The bird belly biomimetic structure of the low-resistance cooling unit includes: a first section, a second section, a third section, a fourth section and a fifth section, which are integrally formed. The first section, the second section, the third section, the fourth section and the fifth section are arranged sequentially along the fluid flow direction. The first section is located at the fluid inlet end.

[0010] The sides of the first and second segments form a smoothly transitioning concave curved surface, and the sides of the third, fourth and fifth segments form a smoothly transitioning convex curved surface, with the concave curved surface and the convex curved surface transitioning smoothly.

[0011] Optionally, the first segment includes two concave first arc surfaces, which are symmetrically arranged. The tops of the two first arc surfaces intersect at a first ridge line. The bottom edge of the first arc surface is a straight line, and the first ridge line is a straight line. The included angle between the bottom edges of the two first arc surfaces is an acute angle, and the intersection point of the first ridge line and the bottom edges of the two first arc surfaces is located at the fluid inflow end.

[0012] Optionally, the second segment includes two concave second arc surfaces, which are symmetrically arranged. The tail end of the first arc surface smoothly transitions to the front end of the second arc surface. The tops of the two second arc surfaces intersect at a second ridge line. The bottom edge of the second arc surface is a straight line, and the bottom edge of the first arc surface is collinear with the bottom edge of the second arc surface. The second ridge line is a concave curve, and the front end of the second ridge line is tangent to the tail end of the first ridge line.

[0013] Optionally, the third segment includes two convex third arc surfaces, which are symmetrically arranged. The tail end of the second arc surface smoothly transitions to the front end of the third arc surface. The tops of the two third arc surfaces converge at a third ridge line. The bottom edge of the third arc surface is an arc, and the tail end of the bottom edge of the second arc surface is tangent to the front end of the bottom edge of the third arc surface. The third ridge line is a convex curve, and the front end of the third ridge line is tangent to the tail end of the second ridge line.

[0014] Optionally, the fourth segment includes a fourth arc surface, and the tail ends of the two third arc surfaces smoothly transition to the front end of the fourth arc surface. The fourth arc surface is an outwardly convex arc surface, and the fourth arc surface is formed by a gradual transition from the large diameter end to the small diameter end through a transition arc line. The front end of the transition arc line is tangent to the tail end of the bottom edge of the third arc surface.

[0015] Optionally, the fifth segment is a semi-elliptical cone structure, and the large-diameter end of the fifth segment is connected to the small-diameter end of the fourth segment;

[0016] The tail end of the fourth arc surface smoothly transitions to the front end of the fifth side segment;

[0017] The bottom edge of the fifth segment is a straight line, and the front end of the bottom edge of the fifth segment is tangent to the tail end of the transition arc.

[0018] The angle between the two base sides of the fifth segment is an acute angle.

[0019] Optionally, the included angle between the bottom edges of the two first arc surfaces is 60°.

[0020] Optionally, the included angle between the two bottom edges of the fifth segment is 30°.

[0021] A low-resistance cooling unit includes a base and a plurality of biomimetic unit groups arranged sequentially on the base along the fluid flow direction. The biomimetic unit groups include a plurality of bird belly biomimetic structures of the aforementioned low-resistance cooling unit arranged at intervals. The plurality of bird belly biomimetic structures are distributed at intervals along a direction perpendicular to the fluid flow direction.

[0022] Several bird belly biomimetic structures are spaced apart between two adjacent biomimetic unit groups.

[0023] Each low-resistance cooling unit is provided with two biomimetic unit groups, and the spacing between two adjacent bird belly biomimetic structures in the same biomimetic unit group is equal.

[0024] The cooling channel has several low-resistance cooling units arranged at equal intervals at both its top and bottom.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] This invention employs a biomimetic structure to increase the heat exchange area, enhance the contact between the gas and the heat exchange surface, and reduce flow resistance. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is an isometric view of the bird belly biomimetic structure of the low-resistance cooling unit of the present invention;

[0029] Figure 2 The image shows a right view of the bird's belly biomimetic structure of the low-resistance cooling unit of the present invention.

[0030] Figure 3 This is a front view of the bird's belly biomimetic structure of the low-resistance cooling unit of the present invention.

[0031] Figure 4 This is a top view of the bird's belly biomimetic structure of the low-resistance cooling unit of the present invention.

[0032] Figure 5 For the present invention Figure 2 AA section diagram;

[0033] Figure 6 For the present invention Figure 2 Middle BB section view;

[0034] Figure 7 For the present invention Figure 2 C-section view;

[0035] Figure 8 For the present invention Figure 2 Cross-sectional view of DD;

[0036] Figure 9 This is a top view of the low-resistance cooling unit of the present invention;

[0037] Figure 10 This is a diagonal view of the low-resistance cooling unit of the present invention;

[0038] Figure 11 This is a right view of the cooling channel of the present invention;

[0039] Figure 12 This is a front view of the present invention;

[0040] Figure 13 Right view of the internal cooling channels of a turbine blade with conventional straight ribs;

[0041] Figure 14 A front view of the internal cooling channels of a turbine blade with conventional straight ribs;

[0042] Figure 15 This is a comparison chart of the heat transfer coefficients of the present invention and conventional cooling channels;

[0043] Among them, 1. First paragraph; 2. Second paragraph; 3. Third paragraph; 4. Fourth paragraph; 5. Fifth paragraph. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Reference Figures 1 to 15 The present invention discloses a bird belly biomimetic structure for a low-resistance cooling unit, comprising: a first segment 1, a second segment 2, a third segment 3, a fourth segment 4 and a fifth segment 5 integrally formed, wherein the first segment 1, the second segment 2, the third segment 3, the fourth segment 4 and the fifth segment 5 are arranged sequentially along the fluid flow direction, and the first segment 1 is located at the fluid inflow end.

[0047] The sides of the first segment 1 and the second segment 2 form a smoothly transitioning concave surface, while the sides of the third segment 3, the fourth segment 4 and the fifth segment 5 form a smoothly transitioning convex surface. The concave and convex surfaces transition smoothly from each other.

[0048] This invention employs a biomimetic structure to increase the heat exchange area, enhance the contact between the gas and the heat exchange surface, and reduce flow resistance.

[0049] The main structure of this invention is composed of a biomimetic low-resistance cooling enhancement structure unit inspired by the belly of a falcon. This low-resistance cooling unit's belly-inspired structure is formed by five curved surfaces. The first segment (1) has a straight edge that is tangent to the arc of the second segment (2) at its intersection. The second segment (2), the third segment (3), and the fourth segment (4) are three arcs with different radii, their radii determined by the geometric relationship of their tangency at the intersection. The fifth segment (5) has a straight edge.

[0050] The height of the bird's belly biomimetic structure in the low-resistance cooling unit is h.

[0051] As an optional implementation, the first segment 1 includes two concave first arc surfaces, which are symmetrically arranged. The tops of the two first arc surfaces intersect at a first ridge line. The bottom edge of the first arc surface is a straight line, the first ridge line is a straight line, the included angle between the bottom edges of the two first arc surfaces is an acute angle, and the intersection point of the first ridge line and the bottom edges of the two first arc surfaces is located at the fluid inflow end.

[0052] Among them, the length 'a' of the first segment 1 satisfies a = 0.5h.

[0053] The height of the end of the first ridge furthest from the intersection point satisfies: h a =0.1h.

[0054] Among them, the cross section of section AA at the junction of the first segment 1 and the second segment 2 is a concave circular arc triangle.

[0055] The curve formula for this concave arc is (right half or left half):

[0056]

[0057] Among them, the first arc surface is a curved surface that transitions from the intersection point to the concave arc. The curvature of the side curves of each section parallel to the AA section on the first arc surface gradually decreases to the curvature of the concave arc of the AA section. The first arc surface is a part of an oblique conical surface with the intersection point as the tip and the concave arc as the base circle.

[0058] As an optional implementation, the second segment 2 includes two concave second arc surfaces, which are symmetrically arranged. The tail end of the first arc surface smoothly transitions to the front end of the second arc surface. The tops of the two second arc surfaces intersect at a second ridge line. The bottom edge of the second arc surface is a straight line, and the bottom edge of the first arc surface is collinear with the bottom edge of the second arc surface. The second ridge line is a concave curve, and the front end of the second ridge line is tangent to the tail end of the first ridge line.

[0059] The curve formula for the second ridge line satisfies:

[0060] The height of the tail end of the second ridge line satisfies: h b =0.1125h.

[0061] The second arc surface is an inwardly concave arc surface that starts from the concave arc at the tail end of the first arc surface and smoothly transitions to the straight line of the side of the triangular cross section at the tail end of the second arc surface.

[0062] Among them, the length b of the second segment 2 satisfies b = 0.25h.

[0063] As an optional implementation, the third segment 3 includes two convex third arc surfaces, which are symmetrically arranged. The tail end of the second arc surface and the front end of the third arc surface are smoothly transitioned. The tops of the two third arc surfaces meet at a third ridge line. The bottom edge of the third arc surface is an arc, and the tail end of the bottom edge of the second arc surface is tangent to the front end of the bottom edge of the third arc surface. The third ridge line is a convex curve, and the front end of the third ridge line is tangent to the tail end of the second ridge line.

[0064] The curve formula for the bottom edge of the third arc surface satisfies: R c =3h.

[0065] Among them, the length c of the third segment 3 satisfies c = 1.5h.

[0066] As an optional implementation, the fourth segment 4 includes a fourth arc surface, the tail ends of the two third arc surfaces are smoothly transitioned to the front end of the fourth arc surface, the fourth arc surface is an outwardly convex arc surface, the fourth arc surface is formed by a gradual transition from the large diameter end to the small diameter end through a transition arc line, and the front end of the transition arc line is tangent to the tail end of the bottom edge of the third arc surface.

[0067] The formula for the curve at the large diameter end of the fourth arc surface is:

[0068] The formula for the curve at the small diameter end of the fourth arc surface is:

[0069] The curve formula for the transition arc of the fourth arc surface is:

[0070] Ridge (elevation) arc formula:

[0071]

[0072] Radius of the edge arc:

[0073]

[0074] Among them, the length d of the fourth segment 4 satisfies d = 1.25h.

[0075] As an optional implementation, the fifth segment 5 is a semi-elliptical cone structure, with the large-diameter end of the fifth segment 5 connected to the small-diameter end of the fourth segment 4.

[0076] The tail end of the fourth arc surface and the front end of the fifth segment 5 sides transition smoothly;

[0077] The bottom edge of the fifth segment 5 is a straight line, and the front end of the bottom edge of the fifth segment 5 is tangent to the tail end of the transition arc.

[0078] The angle between the two bases of the fifth segment 5 is an acute angle.

[0079] The total length l satisfies l = 6h.

[0080] The formula for the curve at the large diameter end of segment 5 is:

[0081]

[0082] As an alternative implementation, the included angle between the bottom edges of the two first arc surfaces is 60°.

[0083] As an alternative implementation, the included angle between the two bottom edges of the fifth segment 5 is 30°.

[0084] As an alternative implementation, the overall height h of the bird's belly biomimetic structure of the low-resistance cooling unit is 2mm.

[0085] As an optional implementation, the total length of the bird belly biomimetic structure of the low-resistance cooling unit is l = 2h = 12mm, the length of the first segment 1 is a = 0.5h = 1mm, the length of the second segment 2 is b = 0.25h = 1mm, the length of the third segment 3 is c = 1.5h = 3mm, the length of the fourth segment 4 is d = 1.25h = 2.5mm, and the length of the fifth segment 5 is 4.5mm.

[0086] The sides of the first segment 1 and the second segment 2 form an equilateral triangle, which is then tangent to the base of the third arc of the third segment 3. The radius of the arc of the base of the third arc is R = 3h = 6mm. The side of the fourth segment 4 is an arc, i.e., a transition arc, which is tangent to the intersection of the third segment 3 and the fourth segment 4. The two sides of the fifth segment 5 form an isosceles triangle with a vertex angle of 30°.

[0087] The height at section AA is h. a =0.20mm.

[0088] The section BB is a regular triangle.

[0089] The section at point CC is a semi-ellipse.

[0090] The section DD is a semi-ellipse.

[0091] The present invention also includes:

[0092] The low-resistance cooling unit includes a base and a plurality of biomimetic unit groups arranged sequentially on the base along the fluid flow direction. The biomimetic unit groups include a plurality of bird belly biomimetic structures of the aforementioned low-resistance cooling unit arranged at intervals. The plurality of bird belly biomimetic structures are distributed at intervals along a direction perpendicular to the fluid flow direction.

[0093] Several bird belly-like bionic structures are spaced apart between two adjacent bionic unit groups.

[0094] Each low-resistance cooling unit has two biomimetic unit groups, and the spacing between two adjacent bird belly biomimetic structures in the same biomimetic unit group is equal.

[0095] As an optional implementation, the low-resistance cooling unit of the present invention includes a base, which is a copper block 30mm long and 24mm wide. A staggered bird-belly-inspired structure is disposed on the base, with a longitudinal spacing of 6mm and a transverse spacing of 10mm between the bird-belly-inspired structures.

[0096] The copper block is 5mm high to ensure the uniformity of the internal temperature of the copper block.

[0097] The cooling channel has several low-resistance cooling units arranged at equal intervals at both its top and bottom.

[0098] As an optional implementation, the cooling channel is 354 mm long and 15 mm high, with 12 copper blocks in 6 groups arranged on both sides. The copper blocks are decorated with staggered bird belly-inspired structures. The channel, except for the copper blocks, is a pure fluid domain.

[0099] Specifically, the cooling channel width is 30mm.

[0100] As a comparison, a conventional ribbed internal cooling channel for turbine blades was provided. The basic parameters of this conventional channel are the same as those of the internal cooling channel for turbine blades with a bird's belly biomimetic structure. The channel is 354 mm long and 15 mm high, with 6 groups of 12 copper blocks on both sides. The copper blocks are equipped with square cross-section ribs with the same height as the bird's belly biomimetic low-resistance cooling enhancement structure unit, with a height h = 2 mm.

[0101] A comparison of the heat transfer coefficients of two cooling channels was obtained, showing the results for the internal cooling channels of turbine blades with a biomimetic low-resistance cooling enhancement structure unit inspired by the belly of a falcon and conventional straight ribs. Numerical calculations using the two channels showed that, under the same operating conditions, the Nusselt number was increased by an average of 14.4%, while the flow resistance was only 30.5% of that of the conventional straight-rib structure.

[0102] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "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, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0103] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A bird-belly-inspired biomimetic structure for a low-resistance cooling unit, characterized in that, include: The first section (1), the second section (2), the third section (3), the fourth section (4) and the fifth section (5) are integrally formed. The first section (1), the second section (2), the third section (3), the fourth section (4) and the fifth section (5) are arranged sequentially along the fluid flow direction. The first section (1) is located at the fluid inflow end. The sides of the first segment (1) and the second segment (2) form a smoothly transitioning concave surface, and the sides of the third segment (3), the fourth segment (4) and the fifth segment (5) form a smoothly transitioning convex surface, with the concave surface and the convex surface transitioning smoothly.

2. The bird-belly biomimetic structure of the low-resistance cooling unit according to claim 1, characterized in that, The first segment (1) includes two concave first arc surfaces, which are symmetrically arranged. The tops of the two first arc surfaces intersect at a first ridge line. The bottom edge of the first arc surface is a straight line, and the first ridge line is a straight line. The included angle between the bottom edges of the two first arc surfaces is an acute angle, and the intersection of the first ridge line and the bottom edges of the two first arc surfaces is located at the fluid inflow end.

3. The bird-belly biomimetic structure of the low-resistance cooling unit according to claim 2, characterized in that, The second segment (2) includes two concave second arc surfaces, which are symmetrically arranged. The tail end of the first arc surface and the front end of the second arc surface are smoothly transitioned. The tops of the two second arc surfaces intersect at a second ridge line. The bottom edge of the second arc surface is a straight line. The bottom edge of the first arc surface and the bottom edge of the second arc surface are collinear. The second ridge line is a concave curve. The front end of the second ridge line is tangent to the tail end of the first ridge line.

4. The bird belly-inspired structure of the low-resistance cooling unit according to claim 3, characterized in that, The third segment (3) includes two convex third arc surfaces, which are symmetrically arranged. The tail end of the second arc surface smoothly transitions to the front end of the third arc surface. The tops of the two third arc surfaces intersect at a third ridge line. The bottom edge of the third arc surface is an arc, and the tail end of the bottom edge of the second arc surface is tangent to the front end of the bottom edge of the third arc surface. The third ridge line is a convex curve, and the front end of the third ridge line is tangent to the tail end of the second ridge line.

5. The bird belly-inspired structure of the low-resistance cooling unit according to claim 4, characterized in that, The fourth segment (4) includes a fourth arc surface. The tail ends of the two third arc surfaces smoothly transition to the front end of the fourth arc surface. The fourth arc surface is an outwardly convex arc surface. The fourth arc surface is formed by a gradual transition from the large diameter end to the small diameter end through a transition arc line. The front end of the transition arc line is tangent to the tail end of the bottom edge of the third arc surface.

6. The bird belly-inspired structure of the low-resistance cooling unit according to claim 5, characterized in that, The fifth segment (5) is a semi-elliptical cone structure, and the large diameter end of the fifth segment (5) is connected to the small diameter end of the fourth segment (4); The tail end of the fourth arc surface smoothly transitions to the front end of the side of the fifth segment (5); The bottom edge of the fifth segment (5) is a straight line, and the front end of the bottom edge of the fifth segment (5) is tangent to the tail end of the transition arc. The angle between the two bottom edges of the fifth segment (5) is an acute angle.

7. The bird belly-inspired structure of the low-resistance cooling unit according to claim 2, characterized in that, The included angle between the bottom edges of the two first arc surfaces is 60°.

8. The bird belly-inspired structure of the low-resistance cooling unit according to claim 6, characterized in that, The angle between the two bottom edges of the fifth segment (5) is 30°.

9. A low-resistance cooling unit, characterized in that: The device includes a base and a plurality of biomimetic unit groups arranged sequentially on the base along the fluid flow direction. The biomimetic unit groups include a plurality of bird belly biomimetic structures of low-resistance cooling units as described in any one of claims 1-8, which are spaced apart. The plurality of bird belly biomimetic structures are spaced apart along a direction perpendicular to the fluid flow direction.

10. A cooling channel, characterized in that, The top and bottom of the cooling channel are each provided with a plurality of low-resistance cooling units as described in claim 9, which are arranged at equal intervals.

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