A method for designing a gas film cooling hole outlet profile based on a multi-segment spline curve

Abstract

The application discloses a kind of gas film cooling hole outlet pass design methods based on multi-segment spline curve, comprising the following steps: S1: determine the specified area range of the outlet pass of gas film cooling hole;S2: according to the specified area range adds the geometric constraint of multi-segment parameterization spline curve, determines the multi-segment parameterization spline curve representation of outlet pass;S3: according to the inlet pass of circle and multi-segment parameterization spline curve representation, establish the three-dimensional model of gas film cooling hole;S4: to the three-dimensional model of gas film cooling hole is simulated, obtains optimal outlet pass.This based on multi-segment spline curve gas film cooling hole outlet pass design method can obtain optimal outlet pass K2 and its design parameter, or design excellent pass outside existing pass, reach higher gas film cooling efficiency, save a lot of design, experimental cost and the like advantages.

Description

Technical Field

[0001] This invention relates to the field of film cooling technology, and in particular to a method for designing the outlet orifice shape of film cooling holes based on multi-segment spline curves. Background Technology

[0002] Film cooling (FSC) is a highly efficient method for cooling turbine blades. It involves delivering a cooler gaseous coolant to the wall surface requiring thermal protection, where it forms a thin film along the direction of the hot gas flow. This film isolates the solid wall surface from the hot gas flow, preventing overheating damage caused by direct contact with the gas. Cylindrical FSC orifices (both inlet and outlet orifices are circular) are the most common and easiest to manufacture. However, their cooling efficiency and spanwise coverage are insufficient. Researchers have developed different types of irregularly shaped FSC orifices (generally with circular inlet orifices and non-circular outlet orifices) to effectively reduce the penetration of the cooling jet into the main flow, making it easier for the cooling film to adhere to the wall surface and thus achieving better FSC performance. Designing better outlet orifice shapes to achieve better FSC performance is currently a hot research topic in FSC.

[0003] In recent years, scholars have proposed and studied a number of outlet orifice shapes, such as circular groove, fan, heart, and elliptical shapes. These outlet orifice shapes have significantly improved cooling efficiency and spanwise coverage compared to cylindrical film cooling orifices. Based on this, some scholars have also attempted to optimize the geometric parameters of these outlet orifice shapes. However, due to various factors such as the selection of the outlet orifice type and the choice of orifice design parameters, it is difficult to obtain the optimal orifice shape and its design parameters, or to design an excellent orifice shape beyond existing ones. Therefore, this invention comprehensively considers the geometric structures of different types of outlet orifice shapes and proposes a new parametric design method for outlet orifice shapes. This method can cover the design of various orifice shapes, such as circular groove, fan, heart, elliptical, and figure-eight shaped orifices, and optimize their design parameters. Furthermore, based on design and optimization requirements, it may also generate other types of excellent orifice shapes and film cooling orifice geometric parameters, achieving higher film cooling efficiency, which is of great significance for guiding engineering practice. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a gas film cooling hole outlet hole design method based on multi-segment spline curves, which can obtain the best outlet hole shape K2 and its design parameters, or design an excellent hole shape outside the existing hole shape, achieve high gas film cooling efficiency, and save a lot of design and experimental costs.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve includes the following steps:

[0007] S1: Determine the specified area range of the outlet orifice type of the film cooling hole;

[0008] S2: Based on the specified area range, add geometric constraints to multiple parametric spline curves to determine the multi-segment parametric spline curve representation of the outlet orifice;

[0009] S3: Based on the circular inlet orifice shape and the multi-segment parametric spline curve representation, establish a three-dimensional model of the air film cooling hole;

[0010] S4: Simulate the three-dimensional model of the air film cooling hole to obtain the optimal outlet hole shape.

[0011] The specified area is a rectangular range of length L and width W, where L is 1d to 6d and W is 1d to 8d, and d is the diameter of the circular inlet hole.

[0012] In S2, the multi-segment parametric spline curve of the outlet orifice K2 is an axisymmetric curve. A rectangular coordinate system is established with the central axis of symmetry of the outlet orifice K2 as the x-axis and the width direction of the air film cooling hole as the y-axis. The geometric constraints include four constraint points A, B, C, and D located on half of the multi-segment parametric spline curve. The coordinates of A in the rectangular coordinate system are (0, 0), the coordinates of B in the rectangular coordinate system are (xb, w / 2), the coordinates of C in the rectangular coordinate system are (l, yc), and the coordinates of D in the rectangular coordinate system are (xd, 0). The coordinates of xb, yc, xd, l, and w are all optimizable parametric variables. The w is the actual width of the outlet orifice (K2), and the l is the actual length of the outlet orifice (K2), where 0≤l≤L, 0≤w≤W, 0≤l≤L, 0≤xb≤l, 0≤yc≤w / 2, and 0≤xd≤l.

[0013] The geometric constraints also include multiple constraint points located between constraint points A and B, multiple constraint points located between constraint points B and C, and multiple constraint points located between constraint points C and D.

[0014] The constraint points between constraints A and B include B1, B2, and B3; the constraint points between constraints B and C include C1, C2, and C3; and the constraint points between constraints C and D include D1, D2, and D3. The coordinates of B1, B2, B3, C1, C2, C3, D1, D2, and D3 in the Cartesian coordinate system are (0, y2), (x3, y3), (x4, w / 2), (x6, w / 2), and (x7, w / 2), respectively. (l, y8), (l, y10), (x11, y11), (x12, y12), where 0≤y2≤w / 2, 0≤x3≤xb, 0≤y3≤w / 2, x3≤x4≤xb, xb≤x6≤l, x6≤x7≤l, yc≤y7≤w / 2, yc≤y8≤y7, 0≤y10≤yc, x12≤x11≤l, 0≤y11≤y10, 0≤x12≤l, 0≤y12≤y11.

[0015] In S2, the multi-segment parametric spline curves are elliptical, rectangular, sector-shaped, heart-shaped, or V-shaped curves.

[0016] In step S4, the optimal performance parameters of the air film cooling hole are obtained through simulation, and the optimal performance parameters are weighted and summed to obtain the optimal outlet hole shape.

[0017] The performance parameters of the film cooling holes include the film cooling efficiency based on area average. and aerodynamic loss coefficient Cp

[0018]

[0019] Where Tg is the mainstream temperature, Tav is the adiabatic wall temperature, and Tc is the cooling flow temperature;

[0020] Film cooling efficiency based on area average

[0021]

[0022] Where A is the downstream plane area of ​​the air film cooling hole outlet;

[0023]

[0024] Where p1, ρ1, and u1 are the average total pressure, average density, and average velocity at the outlet of the computational domain, respectively;

[0025]

[0026] Where mc and mh are the mass flow rates of the cold flow and the mainstream, respectively; p0,c,t and p0,h,t are the average total mass pressures at the inlet of the cold flow and the mainstream, respectively.

[0027] In step S4, the three-dimensional model of the air film cooling hole is simulated using computational fluid dynamics simulation software.

[0028] The computational fluid dynamics simulation software is ANSYS.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] This invention presents a method for designing the outlet orifice shape of a film cooling hole based on multi-segment spline curves. The method constructs the outlet orifice shape using multi-segment parametric spline curves and optimizes the geometric constraints of these curves through numerical simulation, 3D modeling, and 3D model simulation, thereby obtaining a high-performance outlet orifice shape. Using multi-segment parametric spline curves to design the outlet orifice shape allows for free definition of the outlet orifice shape within a specified area. By geometrically associating or fixing some constraint points on the multi-segment parametric spline curves, various orifice shapes can be obtained, including classic circular holes, elliptical holes, circular groove holes, fan-shaped holes, heart-shaped holes, and figure-eight-shaped holes. The structural parameters of these orifice shapes can then be optimized. Furthermore, by relaxing the constraints on the multi-segment parametric spline curves, even more diverse orifice shapes can be obtained beyond existing ones. Guided by this design method, the optimal outlet orifice shape and its design parameters can be obtained, or superior orifice shapes can be designed beyond existing ones, achieving high film cooling efficiency and saving significant design and experimental costs. Attached Figure Description

[0031] Figure 1 This is a flowchart of the gas film cooling hole outlet orifice design method based on multi-segment spline curves according to the present invention.

[0032] Figure 2 This is a three-dimensional model diagram of the air film cooling hole based on the air film cooling hole outlet orifice design method of the present invention based on multi-segment spline curve.

[0033] Figure 3 This invention relates to a multi-segment parametric spline curve diagram of the gas film cooling hole outlet orifice design method based on multi-segment spline curves.

[0034] Figure 4 This is a square diagram of a multi-segment parametric spline curve, which is the design method for the outlet orifice shape of a film cooling hole based on a multi-segment spline curve according to the present invention.

[0035] Figure 5 This is a sector diagram of the multi-segment parametric spline curve of the gas film cooling hole outlet orifice design method based on multi-segment spline curves of the present invention.

[0036] Figure 6 This invention relates to a cardioid diagram of a multi-segment parametric spline curve for designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve.

[0037] Figure 7 This invention presents a V-shaped diagram of a multi-segment parametric spline curve based on a multi-segment spline curve-based method for designing the outlet orifice shape of a film cooling hole.

[0038] Figure 8 This invention provides a three-dimensional model for simulating and designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve.

[0039] The labels in the diagram represent:

[0040] K1, inlet orifice type; K2, outlet orifice type; N, cold flow inlet; Z, main flow channel. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] As shown in this disclosure and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. The terms "connected" or "linked" are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect.

[0043] Figures 1 to 8 This paper illustrates an embodiment of the gas film cooling hole outlet orifice design method based on multi-segment spline curves according to the present invention. The method includes the following steps:

[0044] S1: Determine the specified area range of the outlet orifice type K2 of the film cooling hole;

[0045] S2: Based on the specified area range, add geometric constraints to multiple parametric spline curves to determine the multi-segment parametric spline curve representation of the outlet orifice K2;

[0046] S3: Based on the circular inlet orifice type K1 and the multi-segment parametric spline curve representation, establish a three-dimensional model of the air film cooling hole;

[0047] S4: Simulate the three-dimensional model of the air film cooling hole to obtain the optimal outlet hole shape K2.

[0048] This paper presents a method for designing the outlet orifice shape of a film cooling hole based on multi-segment spline curves. The method constructs the outlet orifice shape K2 of the film cooling hole using multi-segment parametric spline curves. The geometric constraints of the multi-segment parametric spline curves are optimized through numerical simulation, 3D modeling, and 3D model simulation to obtain a high-performance outlet orifice shape K2. Designing the outlet orifice shape K2 using multi-segment parametric spline curves allows for free definition of K2 within a specified area. By geometrically associating or fixing some constraint points on the multi-segment parametric spline curves, various orifice shapes such as classic circular holes, elliptical holes, circular groove holes, fan-shaped holes, heart-shaped holes, and figure-eight-shaped holes can be obtained, and the structural parameters of these orifice shapes can be optimized. Furthermore, by relaxing the constraints on the constraint points of the multi-segment parametric spline curves, even more diverse orifice shapes can be obtained beyond the existing ones. Guided by this design method, the optimal outlet orifice K2 and its design parameters can be obtained, or an excellent orifice can be designed in addition to the existing orifice, achieving high film cooling efficiency and saving a lot of design and experimental costs.

[0049] In this embodiment, the defined area is a rectangular range with length L and width W, where L is 1d to 6d and W is 1d to 8d, and d is the diameter of the circular inlet aperture. Optimally, L is 3d and W is 3d.

[0050] In this embodiment, in S2, the multi-segment parametric spline curve of the outlet orifice K2 is an axisymmetric curve. A rectangular coordinate system is established with the central axis of symmetry of the outlet orifice K2 of the air film cooling hole as the x-axis and the width direction of the air film cooling hole as the y-axis. The geometric constraints include four constraint points A, B, C, and D located on half of the multi-segment parametric spline curve. The coordinates of A in the rectangular coordinate system are (0, 0), the coordinates of B in the rectangular coordinate system are (xb, w / 2), the coordinates of C in the rectangular coordinate system are (l, yc), and the coordinates of D in the rectangular coordinate system are (xd, 0). xb, yc, xd, l, and w are all optimizable parametric variables. w is the actual width of the outlet orifice (K2), and l is the actual length of the outlet orifice (K2), where 0≤l≤L, 0≤w≤W, 0≤l≤L, 0≤xb≤l, 0≤yc≤w / 2, and 0≤xd≤l.

[0051] In this embodiment, the geometric constraints also include multiple constraint points located between constraint points A and B, multiple constraint points located between constraint points B and C, and multiple constraint points located between constraint points C and D. Multiple constraint points are set between constraint points A and B to adjust the shape of spline curve segment AB; multiple constraint points are set between constraint points B and C to adjust the shape of spline curve segment BC; and multiple constraint points are set between constraint points C and D to adjust the shape of spline curve segment CD.

[0052] In this embodiment, the constraint points between constraints A and B include B1, B2, and B3; the constraint points between constraints B and C include C1, C2, and C3; and the constraint points between constraints C and D include D1, D2, and D3. The coordinates of B1, B2, B3, C1, C2, C3, D1, D2, and D3 in the Cartesian coordinate system are (0, y2), (x3, y3), (x4, w / 2), (x6, w / 2), (x7, w / 2), (...). l, y8), (l, y10), (x11, y11), (x12, y12), where 0≤y2≤w / 2, 0≤x3≤xb, 0≤y3≤w / 2, x3≤x4≤xb, xb≤x6≤l, x6≤x7≤l, yc≤y7≤w / 2, yc≤y8≤y7, 0≤y10≤yc, x12≤x11≤l, 0≤y11≤y10, 0≤x12≤l, 0≤y12≤y11.

[0053] In this embodiment, in S2, the multi-segment parametric spline curves are elliptical, rectangular, sector-shaped, heart-shaped, or V-shaped curves.

[0054] In this embodiment, in S4, the optimal performance parameters of the air film cooling hole are obtained through simulation, and the optimal performance parameters are weighted and summed to obtain the optimal outlet hole type (K2).

[0055] In this embodiment, the performance parameters of the film cooling holes include the film cooling efficiency value based on area average. (hereinafter referred to as average film cooling efficiency) and aerodynamic loss coefficient Cp,

[0056]

[0057] Where Tg is the mainstream temperature, Tav is the adiabatic wall temperature, and Tc is the cooling flow temperature;

[0058] Film cooling efficiency based on area average

[0059]

[0060] Where A is the downstream plane area of ​​the air film cooling hole outlet;

[0061]

[0062] Where p1, ρ1, and u1 are the average total pressure, average density, and average velocity at the outlet of the computational domain, respectively;

[0063]

[0064] Where mc and mh are the mass flow rates of the cold flow and the mainstream, respectively; p0,c,t and p0,h,t are the average total mass pressures at the inlet of the cold flow and the mainstream, respectively.

[0065] This invention aims to design an outlet orifice shape for film cooling (FSR) holes that enables them to achieve superior performance. Many parameters are used to evaluate FSR hole performance, including average FSR efficiency, cooling uniformity, aerodynamic loss system, and high-efficiency airflow ratio range, among which average FSR efficiency and aerodynamic loss system are the most important. This invention uses average FSR efficiency and aerodynamic loss system as the objectives for optimizing FSR holes, but it is not limited to these parameters. Under specific conditions, other FSR hole performance evaluation indicators, such as cooling uniformity, can be used as optimization objectives. This invention uses average FSR efficiency and aerodynamic loss system as standards for dual-objective optimization. The average FSR efficiency has a weight of 0-1, and the aerodynamic loss system has a weight of 1 minus the weight of the average FSR efficiency. Optimally, the average FSR efficiency weight is 0.7, and the aerodynamic loss system weight is 0.3.

[0066] In this embodiment, in S4, the three-dimensional model of the air film cooling hole is simulated using computational fluid dynamics simulation software.

[0067] In this embodiment, the computational fluid dynamics simulation software is ANSYS.

[0068] This paper presents a design method for the outlet orifice shape of film cooling holes based on multi-segment spline curves, which is used for the design of film cooling holes for turbine blades. d represents the diameter of the inlet orifice shape K1 of the film cooling hole, and d = 3 mm.

[0069] Specifically, this design method includes: Step 1: Based on the design and processing conditions of the air film cooling hole of the turbine blade, determine the specified area range of the outlet hole type K2 of the air film cooling hole, that is, the maximum length and width boundary range of the outlet hole type K1.

[0070] The design of the outlet orifice type K2 of the air film cooling hole is limited to a rectangle with length L and width W. The maximum length L of the outlet orifice type K2 of the air film cooling hole is in the range of 1d to 6d, and 3d is generally used. The maximum width W of the outlet orifice type K2 of the air film cooling hole is in the range of 1d to 8d, and 3d is generally used.

[0071] Step 2: Represent the outlet orifice type K2 of the film cooling hole using a multi-segment parametric spline curve.

[0072] like Figure 2 and Figure 3 As shown, a rectangular coordinate system is established with the central axis of symmetry (i.e., the length direction) of the outlet orifice K2 of the air film cooling hole as the x-axis and the width direction of the outlet orifice K2 of the air film cooling hole as the y-axis.

[0073] like Figure 3 As shown, the half-side profile of the outlet orifice K2 of the film cooling hole is represented by three connected Beizer curves. Besides the first and last two control points (also called constraint points), each Beizer curve segment has three control points in the middle.

[0074] The three Beizer curves are Beizer curve AB, Beizer curve BC, and Beizer curve CD. There are a total of 13 control points on the three Beizer curves, numbered from 1 to 13. Point 1 is point A, the design starting point of the air film cooling hole outlet orifice K2; its position on the coordinate axis is (0, 0). Point 5 is point B, the widest point of the air film cooling hole outlet orifice K2, its position on the coordinate axis is (xb, w / 2), where xb is an optimizable parameter variable with a value range of 0 to 1. Point 9 is point C, the right vertex of the air film cooling hole outlet orifice K2, its position on the coordinate axis is (l, yc), where yc is an optimizable parameter variable with a value range of 0 to w / 2. Point 13 is point D, the design ending point of the air film cooling hole outlet orifice K2, located on the axis of symmetry, its position on the coordinate axis is (xd, 0), where xd is an optimizable parameter variable with a value range of 0 to 1. Points 2, 3, and 4 are intermediate control points of the Beizer curve AB, namely points B1, B2, and B3; points 6, 7, and 8 are intermediate control points of the Beizer curve BC, namely points C1, C2, and C3; and points 10, 11, and 12 are intermediate control points of the Beizer curve CD, namely points D1, D2, and D3.

[0075] The three connected Beizer curves are mirrored with the x-axis as the axis of symmetry to generate a symmetrical curve. The three Beizer curves and their symmetrical curve together form the outlet orifice shape K2 of the film cooling hole.

[0076] To ensure that the drawn air film cooling hole outlet orifice shape K2 does not exceed the specified rectangular range of length L and width W, restrictions are imposed on the position coordinates of some control points. Utilizing the tangent property of the Beizer curve, the geometric constraints for the relevant control points are as follows: For control point 2, the x-direction coordinate is x2 = 0, and the y-direction coordinate y2 ranges from 0 ≤ y2 ≤ w / 2; for control point 3, the x-direction coordinate is 0 ≤ x3 ≤ xb, and the y-direction coordinate y3 ranges from 0 ≤ y3 ≤ w / 2; for control point 4, the x-direction coordinate is x3 ≤ x4 ≤ xb, and the y-direction coordinate is y4 = w / 2; for control point 6, the x-direction coordinate is xb ≤ x6 ≤ l, and the y-direction coordinate is y6 = w / 2; for control point 7, the x-direction coordinate is xb ≤ x6 ≤ l, and the y-direction coordinate is yb ≤ x6 ≤ l; for control point 7, the x-direction coordinate is xb ≤ x6 ≤ l, and the y-direction coordinate is yb ≤ x6 ≤ l. For control point 6, x7 ≤ l, and the range of y-coordinate y7 is yc ≤ y7 ≤ w / 2; for control point 8, x8 = l, and the range of y-coordinate y8 is yc ≤ y8 ≤ y7; for control point 10, x10 = l, and the range of y-coordinate y10 is 0 ≤ y10 ≤ yc; for control point 11, x12 ≤ x11 ≤ l, and the range of y-coordinate y11 is 0 ≤ y11 ≤ y10; for control point 12, x12 ≤ l, and the range of y-coordinate y12 ≤ y11.

[0077] It contains a total of 17 variables: l, w, y2, x3, y3, x4, xb, x6, x7, y7, y8, yc, y10, x11, y11, x12, and xd.

[0078] When y2=0, x3=0, y3=w / 2, x4=l / 2, xb=l / 2, x6=l / 2, x7=l, y7=w / 2, y8=0, yc=0, y10=0, x11=l, y11=0, x12=l, xd=l, as Figure 2 As shown, the outlet orifice shape K2 of the film cooling hole, formed by the three Beizer curves and their symmetrical curves, is elliptical. Using l and w as optimization variables, an ellipsoid with length l and width w can be arbitrarily formed.

[0079] When y2 approaches w / 2, x3 = 0, y3 = w / 2, x4 approaches 0, x6 approaches 1, x7 = 1, y7 = w / 2, y8 approaches w / 2, x11 = 1, x12 = 1, and xd = 1, as follows: Figure 4 As shown, the outlet orifice shape K2 of the film cooling hole, formed by the three Beizer curves and their symmetrical curves, is rectangular. Combined with the inlet circular orifice of the film cooling hole, the resulting film cooling hole is a circular groove.

[0080] By using l and w as optimization variables, a rectangular hole with length l and width w can be arbitrarily formed. At the same time, by slightly changing the values ​​of y2, x4, x6, and y8, certain rounded corners can be formed at the four corners of the rectangular hole.

[0081] When x11 = l, x12 = l, xd = l, and the Bezier curves AB and CD are arcs, as Figure 5 shown, the outlet hole pattern K2 of the film cooling hole formed by the three Bezier curves and their symmetric curves is a sector. By taking l, w, y2, x3, y3, x4, xb, x6, x7, y7, y8, yc, y10, y11 as variables, sector holes with arbitrary structures can be designed.

[0082] When x11 < l, x12 < l, and xd < l, as Figure 6 shown, the outlet hole pattern K2 of the film cooling hole formed by the three Bezier curves and their symmetric curves is a heart shape. By taking l, w, y2, x3, y3, x4, xb, x6, x7, y7, y8, yc, y10, x11, y11, x12, xd as variables, heart-shaped holes with arbitrary structures can be designed.

[0083] When all the control points of a Bezier curve are on a straight line, this Bezier curve is a straight line. Thus, when points 1, 2, 3, 4, 5 are on a straight line, when points 5, 6, 7, 8, 9 are on a straight line, and when points 9, 10, 11, 12, 13 are on a straight line, as Figure 7 shown, the outlet hole pattern K2 of the film cooling hole formed by the three Bezier curves and their symmetric curves is a V shape. By appropriately changing the values of l, w, y2, x3, y3, x4, xb, x6, x7, y7, y8, yc, y10, y11, V-shaped holes with different divergence angles and slot widths can be obtained.

[0084] Step 3: Based on the obtained outlet hole pattern K2 of the film cooling hole and the circular hole at the inlet of the film cooling hole, use surface generation techniques such as lofting to construct a three-dimensional model of the film cooling hole. As Figure 2 shown, construct a three-dimensional model of the film cooling hole in SolidWorks.

[0085] In SolidWorks, use the lofted surface method to generate a three-dimensional model of the film cooling hole by using the inlet of the film cooling hole and the outlet hole pattern K2 obtained in Step 2.

[0086] Step 4: Generate a three-dimensional model for film cooling simulation by combining the three-dimensional model of the film cooling hole and the cold flow inlet N and the main flow channel Z, as Figure 8 shown.

[0087] The 3D model used for film cooling simulation was imported into ANSYS (a finite element analysis system), and a mesh model with 2.2 million cells was selected. Both the main hot flow and the cooling flow used ideal gases, and both inlets used constant velocity inlets. The main hot flow velocity was 25 m / s, and the temperature was 380 K. The cooling flow inlet temperature was 300 K, and the blowing ratio M = 1.

[0088] Simulation calculations and parameter optimization design are performed using the ANSYS fluid simulation module ANSYS Fluent and the parametric design module ANSYS ParameterDesign.

[0089] Using the average film cooling efficiency η and the aerodynamic loss system Cp as optimization objectives, and l and w as optimization variables, an ellipsoidal film cooling orifice was designed. Its optimal structural parameters are l = 6 mm and w = 6 mm. The average film cooling efficiency η of the orifice is 0.20312, and the aerodynamic loss system Cp is 0.030972, representing a 132% increase in average film cooling efficiency η and a 63% reduction in aerodynamic loss system Cp compared to the classic circular orifice.

[0090] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A method for designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve, characterized in that: Includes the following steps: S1: Determine the specified area range of the outlet orifice type (K2) of the film cooling hole; S2: Based on the specified area, add geometric constraints to multiple parametric spline curves to determine the multi-segment parametric spline curve representation of the outlet orifice (K2). The multi-segment parametric spline curve of the outlet orifice (K2) is an axisymmetric curve. A rectangular coordinate system is established with the central axis of symmetry of the air-film cooling hole outlet orifice (K2) as the x-axis and the width direction of the air-film cooling hole as the y-axis. The geometric constraints include four constraint points A, B, C, and D located on half of the multi-segment parametric spline curve. The coordinates of A in the rectangular coordinate system are (0, ..., ...). 0), the coordinates of B in the rectangular coordinate system are (xb, w / 2), the coordinates of C in the rectangular coordinate system are (l, yc), the coordinates of D in the rectangular coordinate system are (xd, 0), xb, yc, xd, l and w are all optimizable parameterized variables, w is the actual width of the outlet orifice (K2), l is the actual length of the outlet orifice (K2), where 0≤l≤L, 0≤w≤W, 0≤l≤L, 0≤xb≤l, 0≤yc≤w / 2, 0≤xd≤l; S3: Based on the circular inlet orifice type (K1) and the multi-segment parametric spline curve representation, establish a three-dimensional model of the air film cooling hole; S4: Simulate the 3D model of the film cooling hole to obtain the optimal performance parameters of the film cooling hole through simulation. Then, perform a weighted summation of the optimal performance parameters to obtain the optimal outlet orifice shape (K2). The performance parameters of the film cooling hole include the film cooling efficiency value based on area average. and aerodynamic loss coefficient Cp, ， Where Tg is the mainstream temperature, Tav is the adiabatic wall temperature, and Tc is the cooling flow temperature; Film cooling efficiency based on area average , ， Where A is the downstream plane area of ​​the air film cooling hole outlet; ， Among them, p1, u1 and u2 are the average total pressure, average density, and average velocity at the outlet of the computational domain, respectively. ， Where mc and mh are the mass flow rates of the cold flow and the mainstream, respectively; p0,c,t and p0,h,t are the average total mass pressures at the inlet of the cold flow and the mainstream, respectively.

2. The method for designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve according to claim 1, characterized in that: The specified area is a rectangular range of length L and width W, where L is 1d to 6d and W is 1d to 8d, and d is the diameter of the circular inlet hole.

3. The method for designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve according to claim 2, characterized in that: The geometric constraints also include multiple constraint points located between constraint points A and B, multiple constraint points located between constraint points B and C, and multiple constraint points located between constraint points C and D.

4. The method for designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve according to claim 3, characterized in that: The constraint points between constraints A and B include B1, B2, and B3; the constraint points between constraints B and C include C1, C2, and C3; and the constraint points between constraints C and D include D1, D2, and D3. The coordinates of B1, B2, B3, C1, C2, C3, D1, D2, and D3 in the Cartesian coordinate system are (0, y2), (x3, y3), (x4, w / 2), (x6, w / 2), and (x7, w / 2), respectively. (l, y8), (l, y10), (x11, y11), (x12, y12), where 0≤y2≤w / 2, 0≤x3≤xb, 0≤y3≤w / 2, x3≤x4≤xb, xb≤x6≤l, x6≤x7≤l, yc≤y7≤w / 2, yc≤y8≤y7, 0≤y10≤yc, x12≤x11≤l, 0≤y11≤y10, 0≤x12≤l, 0≤y12≤y11.

5. The method for designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve according to claim 1, characterized in that: In S2, the multi-segment parametric spline curves are elliptical, rectangular, sector-shaped, heart-shaped, or V-shaped curves.

6. The method for designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve according to any one of claims 1 to 5, characterized in that: In step S4, the three-dimensional model of the air film cooling hole is simulated using computational fluid dynamics simulation software.

7. The method for designing the outlet orifice shape of a film cooling hole based on a multi-segment spline curve according to claim 6, characterized in that: The computational fluid dynamics simulation software is ANSYS.

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