Turbine blade body three-dimensional outer heat exchange boundary construction method based on air film hole distribution

Abstract

The invention provides a turbine blade body three-dimensional outer heat exchange boundary construction method based on air film hole distribution. The turbine blade body three-dimensional outer heat exchange boundary construction method comprises the steps that 1, a preset number of two-dimensional S1 section initial heat exchange boundaries are obtained; 2, geometric parameters and outflow parameters of the air film holes of the blade body are obtained; 3, according to the step 1 and the step 2, interpolating turbine blade three-dimensional exterior surface grid nodes and initial three-dimensional heat exchange boundaries on the turbine blade three-dimensional exterior surface grid nodes, and then drawing actual air film hole distribution on turbine blade three-dimensional exterior surface grids; 4, classifying the drawn actual gas film holes, and determining the influence area of the outflow parameters of the gas film holes; 5, correcting the initial three-dimensional heat exchange boundary in the influence area of the outflow parameters of the air film hole; and 6, the blade body three-dimensional heat exchange boundary structure based on actual air film hole distribution is completed. According to the method, the influence of actual film hole distribution on the temperature of the turbine blade can be reflected, and refined cooling design and high-precision temperature evaluation of the blade are supported.

Description

Technical Field

[0001] The invention relates to the technical field of aeroengines, and in particular to a method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on air film hole distribution. Background Art

[0002] As an efficient cooling measure, film cooling can reduce the gas temperature on the outer wall of the blade by the cold air flowing out of the film holes, avoid direct erosion of the gas on the turbine blades, and play an important protective role for the blades. It is widely used in modern high-performance air-cooled turbine blades.

[0003] In order to evaluate the influence of the cold air flowing out of the film holes on the temperature field of the turbine blades, the industry usually needs to construct the three-dimensional heat transfer boundary of the blade surface required for the calculation of the blade temperature field, and consider the influence of the cold air flowing out of the film holes on the heat transfer boundary. In order to construct the three-dimensional heat transfer boundary of the outer surface corrected by the cold air flowing out of the film holes, the industry currently mainly adopts the method of interpolating the three-dimensional outer surface parameters from the two-dimensional S1 section parameters, that is, first calculate the initial heat transfer boundary on the two-dimensional S1 section without considering the influence of the cold air flowing out of the film holes, and then use the cold air flowing out of the film holes to correct the initial heat transfer boundary on the two-dimensional S1 section without considering the influence of the cold air, and finally use the corrected two-dimensional S1 section heat transfer boundary to interpolate the three-dimensional outer surface heat transfer boundary for subsequent blade temperature field calculations. This method mainly has the following problems:

[0004] 1) It cannot reflect the actual three-dimensional distribution of the film holes, which will lead to over-correction in areas such as the blade tip and blade root that are not affected by the cold air flowing out of the film holes, causing the temperature field evaluation results of the turbine blade to deviate from the actual situation.

[0005] 2) The influence of individual discrete film holes on blade temperature cannot be considered, which is not suitable for the detailed design and evaluation of advanced turbine blade film cooling schemes. Summary of the invention

[0006] In view of this, the present invention provides a method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on the distribution of film holes. The method can efficiently construct a three-dimensional external surface heat exchange boundary of a main channel blade body required for calculating the temperature field of the turbine blade according to the actual distribution of film holes, taking into account the influence of the outflow cooling air from the actual distribution of film holes. The method solves the problem of over-correction of traditional methods in areas not affected by the outflow cooling air from the film holes, and improves the accuracy and reliability of the turbine blade temperature field calculation. At the same time, the method can take into account the influence of individual discrete film holes on the blade temperature, and is suitable for the refined design and evaluation of advanced turbine blade film cooling schemes, and has important engineering practical value.

[0007] The present invention provides the following technical solutions: a method for constructing a three-dimensional external heat exchange boundary of a turbine blade based on film hole distribution, comprising: step 1, obtaining a predetermined number of two-dimensional S1 section initial heat exchange boundaries; step 2, obtaining blade body film hole geometric parameters and film hole outflow parameters; step 3, interpolating the turbine blade three-dimensional outer surface grid nodes and the initial three-dimensional heat exchange boundary on the turbine blade three-dimensional outer surface grid nodes according to step 1 and step 2, and then drawing the actual film hole distribution on the turbine blade three-dimensional outer surface grid; step 4, classifying the drawn actual film holes and determining the influence area of ​​the film hole outflow parameters; step 5, correcting the initial three-dimensional heat exchange boundary within the influence area of ​​the film hole outflow parameters; step 6, completing the construction of the three-dimensional heat exchange boundary of the blade based on the actual film hole distribution.

[0008] Furthermore, the initial heat transfer boundary of the two-dimensional S1 section includes: the node coordinates constituting the S1 section curve and the heat transfer temperature and heat transfer coefficient at the nodes without considering the influence of the film hole outflow parameters.

[0009] Furthermore, the geometric parameters of the film holes on the blade body include the coordinates of the hole center, the hole vector angle and the aperture; the outflow parameters of the film holes include the cold air temperature, density and flow rate.

[0010] Furthermore, step 3 includes: using a predetermined number of two-dimensional S1 section initial heat transfer boundaries obtained in step 1, and using the Lagrangian method to interpolate and construct the turbine blade three-dimensional outer surface mesh nodes and the initial three-dimensional heat transfer boundaries on the turbine blade three-dimensional outer surface mesh nodes.

[0011] Furthermore, step 3 also includes: according to the geometric parameters of the blade film holes obtained in step 2, interpolating and drawing the actual distribution of each film hole.

[0012] Further, step 4 is specifically as follows: according to the longitudinal arrangement or transverse arrangement characteristics of the actual film holes drawn, the blade film holes are classified into a plurality of longitudinally arranged film holes or a plurality of transversely arranged film holes, and the influencing area of ​​the film hole outflow parameters is determined.

[0013] Furthermore, step 5 includes: when multiple film holes affect the same area, the initial three-dimensional heat exchange boundary in the area affected by the film hole outflow parameters is corrected using the superposition effect of the cold air outflow of the film holes.

[0014] Furthermore, step 5 also includes: using the corrected initial three-dimensional heat exchange boundary as the boundary for obtaining the film hole outflow parameters in step 2 to update and calculate the film hole outflow parameters, and then repeating steps 3 to 5 until the film hole outflow parameters change to reach a set value.

[0015] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted in the present invention include at least: according to the actual distribution of film holes, efficiently constructing the three-dimensional external surface heat exchange boundary of the main channel blade body required for the calculation of the temperature field of the turbine blade, which takes into account the influence of the outflow cooling air of the actual distribution of film holes, thereby solving the over-correction problem of traditional methods in the area not affected by the outflow cooling air of the film holes, and improving the accuracy and reliability of the calculation of the temperature field of the turbine blade. At the same time, the method can also consider the influence of individual discrete film holes on the blade temperature, which is suitable for the refined design and evaluation of advanced turbine blade film cooling schemes, and has important engineering practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a specific design flow chart of the method of the present invention;

[0018] Figure 2 is a two-dimensional cross-sectional curve;

[0019] Figure 3 is the initial heat transfer boundary distributed along the 2D cross-sectional curve;

[0020] Figure 4 Reconstruction of 3D surface boundary mesh and actual air film holes;

[0021] Figure 5 It is the initial heat transfer boundary structure of the three-dimensional outer surface;

[0022] Figure 6 It is the classification of air film holes on three-dimensional external surfaces;

[0023] Figure 7 It is the three-dimensional surface partition and air film hole classification;

[0024] Figure 8 This is a schematic diagram for determining the influence area of ​​the entire exhaust film hole;

[0025] Fig. 9 This is a schematic diagram of determining the influence area of ​​a single air film hole in a longitudinal row;

[0026] Fig.10 This is a schematic diagram of determining the influence area of ​​a single air film hole in a horizontal row;

[0027] Fig.11 It is a comparison between the heat exchange boundary constructed by the method of the present invention and the traditional heat exchange boundary. DETAILED DESCRIPTION

[0028] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0029] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0030] like Figure 1-11 As shown, an embodiment of the present invention provides a method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on film hole distribution, comprising:

[0031] Step 1: Obtain a predetermined number of two-dimensional S1 section initial heat exchange boundaries.

[0032] Step 2: Obtain the blade film hole geometric parameters and film hole outflow parameters.

[0033] Step 3: interpolate the initial three-dimensional heat exchange boundary and draw the actual air film pore distribution.

[0034] Step 4: classify the air film holes and determine the influence area of ​​the air film hole outflow parameters.

[0035] Step 5: Correct the initial three-dimensional heat exchange boundary according to the outflow parameters of the air film hole.

[0036] Step 6: Complete the three-dimensional heat exchange boundary construction of the blade body based on the actual air film hole distribution.

[0037] Step 1, according to the requirements of turbine blade heat transfer design, according to the existing method, obtain a predetermined number of two-dimensional S1 section initial heat transfer boundaries on the outer surface of the turbine blade, including the node coordinates x, y, z that constitute the S1 section curve and the initial heat transfer boundaries on the nodes. The initial heat transfer boundaries include the heat transfer temperature and heat transfer coefficient that do not consider the influence of the film hole outflow parameters. The S1 section curve is divided into a blade basin curve PS and a blade back curve SS according to the leading edge endpoint front and the trailing edge endpoint rear, and the relative position of the curve node is defined from the leading edge endpoint front to the trailing edge endpoint rear. The relative position of the leading edge endpoint front is 0.0, and the relative position of the trailing edge endpoint rear is 1.0, such as Figure 2 , Figure 3shown.

[0038] Step 2, obtain the geometric parameters such as the hole center coordinates, hole vector angle and aperture of each air film hole on the outer surface of the turbine blade, and use the existing methods in the industrial sector to solve the cold air outflow parameters flowing through each air film hole, the cold air outflow parameters include cold air temperature, density, flow rate, etc.

[0039] Step 3, using the predetermined number of two-dimensional cross-section initial heat transfer boundaries obtained in step 1, the Lagrangian method is used to interpolate and construct the three-dimensional outer surface grid nodes of the turbine blade and the initial three-dimensional heat transfer boundaries on the outer surface grid nodes. The grid nodes are orthogonal grid nodes in the Cartesian coordinate system, which are used in the subsequent step 4 to locate and determine the influence area of ​​the air film hole. The influence area is represented by the grid nodes that constitute the three-dimensional outer surface. According to the geometric parameters of the air film hole obtained in step 2, the actual distribution of each air film hole is interpolated and drawn, such as Figure 4 , Figure 5 shown.

[0040] Step 4, classifying the actual air film holes and the initial three-dimensional heat exchange boundary partitions, and determining the influence area of ​​the outflow cold air of the air film holes along the flow direction, includes the following steps:

[0041] Step 41, classify the film holes, and classify the film holes of the blade body into a plurality of longitudinally arranged film holes or transversely arranged film holes according to the longitudinal 001 arrangement or transverse 100 arrangement characteristics of the film holes, such as Figure 6 As shown, the air film holes are classified into 6 longitudinally arranged air film hole rows H1 to H6, and 1 transversely arranged air film hole row H7, wherein H1 consists of 3 longitudinally distributed air film holes, H2 consists of 6 longitudinally distributed air film holes, and H7 consists of 5 transversely distributed air film holes.

[0042] Step 42, as Figure 7 As shown in the figure, according to the actual distribution of the film holes and the outflow characteristics of the film holes, the three-dimensional outer surface is divided into 9 characteristic areas Z1~Z9, specifically: including the leading edge film hole distribution area Z1 where H4~H6 are located, the middle and rear chord area Z6 of the blade basin where H1~H3 are located, the basin side blade tip area Z5 where H7 is located, the area Z4 without film holes at the root of the blade basin, the area Z2 without film holes at the root of the leading edge, the area Z3 without film holes at the tip of the leading edge, and similar root, middle and tip areas distributed radially on the back of the blade.

[0043] Step 43, as Figure 8As shown, the influence area of ​​the outflow cold air of each film hole is determined. The following assumptions are made: the outflow cold air of the transversely distributed film holes mainly affects the heat exchange boundary on the longitudinally distributed three-dimensional external surface grid nodes in the downstream direction of the cold air flow, for example, the outflow cold air of the H7 film hole mainly affects the three-dimensional external surface grid nodes in the 001 direction in the Z5 area; the outflow cold air of the longitudinally distributed film holes mainly affects the heat exchange boundary on the transverse three-dimensional external surface grid nodes in the downstream direction of the cold air flow, for example, the outflow cold air of the H1~H3 film holes mainly affects the three-dimensional external surface grid nodes in the 100 direction in the Z6 area; and H4~H6, in addition to affecting the leading edge area Z1 where they are located, also affects the downstream areas Z3 and Z6; Z2 and Z4, based on the experience of the industrial sector, have a certain attenuation effect on the outflow cold air of the film holes in the Z5 and Z6 areas on the blade body close to Z2 and Z4.

[0044] Step 43, determining the influence area of ​​the cold air outflow from each air film hole in each row arranged longitudinally or transversely, using the following method: according to the cold air outflow of adjacent air film holes i and air film holes j, determine the influence width d between the specific air film hole i and the air film hole j ij The downstream impact areas are: T ij is the hole center distance between air film hole i and air film hole j, m i is the cooling air flow rate of the ith air film hole, c i is the influence width weight of the i-th air film hole, m j is the cooling air flow rate of the jth air film hole, c j is the weight of the influence width of the j-th air film hole. The weight can be determined based on the experience of the industrial sector, for example, considering the angle between the air film hole and the three-dimensional outer surface. The smaller the angle, the greater the weight. Preferably, the shape of the air film hole can also be considered. For example, the weight of a fan-shaped hole is greater than that of a circular hole. When the angle and shape of adjacent air film holes are consistent, the weight value can be taken as 1. Fig. 9 In the figure, the air film hole numbered H2-5 has an impact area of ​​the grid nodes within the range of Inf2-5 downstream of it, and the impact width is determined by factors such as the flow rate of air film holes H2-4, H2-5 and H2-6, the angle with the mold surface, and the hole shape. Fig. 9 For H1-H3 and Inf2-6, refer to the above and so on.

[0045] If a film hole is on the outermost side of its row, its influence width in the outer direction of the row can be given according to the influence width on the side with the adjacent film hole in the row, affecting the heat exchange boundary on the three-dimensional outer surface grid node downstream of its cold air outflow.

[0046] If a certain air film hole has no adjacent air film holes, that is, it is a single air film hole, and according to the experience of the industrial sector, its influence width can be considered to be a specific multiple of its aperture, such as usually 2 to 4 times the aperture width, which affects the heat exchange boundary on the three-dimensional external surface grid node downstream of the cold air outflow.

[0047] Step 5, using the outflow parameters of each air film hole obtained in step 2, and according to the existing method for correcting the heat exchange boundary of the cold air outflow from the air film hole, correct the initial heat exchange boundary determined in step 3 at the node within the flow direction influence area of ​​each air film hole determined in step 4.

[0048] When multiple air film holes affect the same area, the superposition effect of the cold air outflow from the air film holes is required, and the method for superimposing the impact effects adopts the existing methods in the industrial sector.

[0049] After completing step 5, the corrected three-dimensional heat exchange boundary of the blade body is used as the calculation input boundary of step 2. The existing method of the industrial sector in step 2 is used to solve the cold air outflow parameters flowing through each film hole again. The newly obtained cold air outflow parameters of the film hole are used as the input of step 5 to correct the initial three-dimensional heat exchange boundary of step 3. Repeat this process so that the cold air outflow parameters of the film hole before and after the iteration of step 2 do not change. The implementation case of the present invention iterates twice, that is, the cold air outflow parameters of the film hole before and after the iteration of step 2 do not change, and the required accuracy requirements are met.

[0050] Step 6. According to the boundary file loading format requirements for calculating the solid domain temperature field of the blade, such as the xx.prof file format required for calculating the solid domain temperature field under the fluent software, output the three-dimensional outer surface mesh node coordinates generated in step 3 and the heat transfer boundaries such as the heat transfer temperature and heat transfer coefficient corrected according to step 5 on each mesh node. This can realize the three-dimensional outer surface heat transfer boundary construction required for the blade temperature field calculation based on the actual film hole distribution, which can be used for the refined design and evaluation of the turbine blade film cooling scheme.

[0051] According to the above description, the present invention provides a method for constructing the heat exchange boundary of the three-dimensional outer surface of the turbine blade body based on the actual distribution of the air film holes. Figures 1 to 11 It can be seen that the feasibility of the present invention.

[0052] It should be noted that, in the figure, S1-1, S1-2, and S1-3 are the first, second, and third two-dimensional S1 cross-sectional curves selected by the example of the method of the present invention, front and rear are the leading edge and trailing edge endpoints of the two-dimensional cross-sectional curve, PS and SS are the blade basin curve and blade back curve of the two-dimensional cross-sectional curve, root and tip are the root area and the tip area of ​​the blade body outer surface, 100 and 001 represent the transverse direction and the longitudinal direction respectively, H1, H2, and H3 are the rows of film holes distributed longitudinally on the blade basin side, H4, H5, and H6 are the rows of film holes distributed longitudinally in the leading edge area, H7 is the row of film holes distributed transversely in the tip area, and Z1, Z 2. Z3 represents the middle area of ​​the leading edge, the root area of ​​the leading edge, and the tip area of ​​the leading edge. Z4, Z5, and Z6 represent the root area of ​​the blade basin, the tip area of ​​the blade basin, and the middle area of ​​the blade basin. Inf1, Inf2, and Inf3 are the influence areas of the longitudinal air film hole rows H1, H2, and H3. Inf7 is the influence area of ​​the transverse air film hole row H7. Inf2-5 and Inf2-6 are the influence areas of the 5th hole H2-5 and the 6th hole H2-6 of the longitudinal air film hole row H2. Inf7-1, Inf7-2, and Inf7-3 are the influence areas of the 1st hole H7-1, the 2nd hole H7-2, and the 3rd hole H7-3 of the transverse air film hole row H7.

[0053] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on film hole distribution, characterized in that: include: Step 1, obtaining a predetermined number of two-dimensional S1 section initial heat exchange boundaries; Step 2, obtaining the blade film hole geometric parameters and the film hole outflow parameters; Step 3, interpolating the three-dimensional outer surface mesh nodes of the turbine blade and the initial three-dimensional heat exchange boundary on the three-dimensional outer surface mesh nodes of the turbine blade according to the steps 1 and 2, and then drawing the actual film hole distribution on the three-dimensional outer surface mesh of the turbine blade; Step 4, classify the drawn actual air film holes and determine the influence area of ​​the air film hole outflow parameters; Step 5, correcting the initial three-dimensional heat exchange boundary in the influence area of ​​the film hole outflow parameters; Step 6: Complete the three-dimensional heat exchange boundary construction of the blade body based on the actual air film hole distribution.

2. The method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on film hole distribution according to claim 1, characterized in that: The two-dimensional S1 section initial heat exchange boundary includes: the node coordinates constituting the S1 section curve and the heat exchange temperature and heat exchange coefficient at the node without considering the influence of the film hole outflow parameters.

3. The method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on film hole distribution according to claim 2, characterized in that: The geometric parameters of the film hole of the blade body include the coordinates of the hole center, the hole vector angle and the hole diameter; the outflow parameters of the film hole include the cold air temperature, density and flow rate.

4. The method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on film hole distribution according to claim 3, characterized in that: The step 3 comprises: Using the predetermined number of two-dimensional S1 section initial heat transfer boundaries obtained in step 1, the three-dimensional outer surface mesh nodes of the turbine blade and the initial three-dimensional heat transfer boundaries on the three-dimensional outer surface mesh nodes of the turbine blade are interpolated and constructed using the Lagrangian method.

5. The method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on film hole distribution according to claim 4, characterized in that: The step 3 also includes: According to the geometric parameters of the blade film holes obtained in step 2, the actual distribution of each film hole is interpolated and drawn.

6. The method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on film hole distribution according to claim 5, characterized in that: The step 4 is specifically as follows: According to the longitudinal arrangement or transverse arrangement characteristics of the actual film holes drawn, the film holes on the blade body are classified into a plurality of longitudinally arranged film holes or a plurality of transversely arranged film holes, and the influencing area of ​​the film hole outflow parameters is determined.

7. The method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on film hole distribution according to claim 5, characterized in that: The step 5 comprises: When multiple film holes affect the same area, the superposition effect of the cold air outflow from the film holes is used to correct the initial three-dimensional heat exchange boundary in the area affected by the film hole outflow parameters.

8. The method for constructing a three-dimensional external heat exchange boundary of a turbine blade body based on film hole distribution according to claim 5, characterized in that: The step 5 also includes: using the corrected initial three-dimensional heat exchange boundary as the boundary for obtaining the film hole outflow parameters in step 2 to update and calculate the film hole outflow parameters, and then repeating steps 3 to 5 until the film hole outflow parameters change to reach a set value.

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