Hydraulic torque converter blade modeling method based on PARSEC function

Abstract

The invention belongs to the technical field of hydraulic transmission of engineering machinery, and particularly discloses a PARSEC function-based hydraulic torque converter blade modeling method, which comprises the following steps of: introducing a PARSEC function curve into the design of a hydraulic torque converter blade profile, and designing a two-dimensional unit blade bone line and a blade thickness distribution curve by utilizing the PARSEC function. A two-dimensional real blade molded line is obtained by rotating and zooming the two-dimensional unit blade molded line, and the whole blade is subjected to full parameterization expression, so that accurate design of the blade is facilitated; and meanwhile, the PARSEC parameter curve is used for blade design, the defects that the blade shape design of a traditional hydraulic torque converter is inaccurate and tedious are overcome, and the transmission performance of the hydraulic torque converter is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic transmission of construction machinery, and particularly relates to a blade modeling method of a torque converter based on the PARSEC function. Background Art

[0002] The torque converter is an important transmission component in the transmission system of construction machinery. Because of its advantages such as torque multiplication, vibration isolation and shock absorption, and stepless speed change, it is widely used in industries such as city buses, loaders, heavy trucks and military tanks. Modern construction machinery is developing towards high speed and heavy load, and more stringent requirements are put forward for high transmission performance and high adaptability performance under extreme working conditions; in order to match the performance of modern construction machinery devices, user requirements put forward higher requirements for the transmission performance of torque converters at high rotational speeds and high power densities. The transmission performance of the torque converter mainly depends on the blade design system of the torque converter. Therefore, developing a new set of blade design methods for torque converters can not only shorten the design cycle of the torque converter and reduce production costs, but also improve the flexibility of the blade profile design of the torque converter and achieve a wider range of transmission performance regulation, greatly enhancing the market competitiveness of the torque converter in the field of construction machinery.

[0003] The design of the torque converter mainly includes the design of the circulating circle and the design of the blades. Among these two designs, the blade design is the most important and also the most complex part, and the performance of the torque converter is directly determined by the quality of the blade design. In the traditional blade modeling method of the torque converter, usually only the blade shape symmetrical about the backbone line can be designed, and the design of asymmetric blade profiles is rarely mentioned, which makes the traditional method have limitations and cannot take into account the design of all types of blade profiles. Secondly, the traditional blade profile design methods do not meet the design theory of streamlined blade profiles, because they mostly use curves such as straight lines, parabolas and arcs for splicing, resulting in poor curvature continuity of the blade profile and the phenomenon of unevenness at the connection of the blade profiles. In addition, when the traditional blade profile design methods are used to design blade profiles with a large bending degree, the phenomena of blade profile distortion and curve winding into a loop are likely to occur, which is a technical defect.

[0004] Therefore, if a new type of blade profile design method can be proposed to achieve high bending degree, high continuity modeling, wide power spectrum range adjustment and simple and rapid design of the torque converter, it is of great significance for enhancing the competitiveness of the torque converter in the field of construction machinery and improving social and economic benefits. Summary of the Invention

[0005] Technical Problems to be Solved

[0006] In view of this, the purpose of the present invention is to provide a method for shaping the blades of a hydrodynamic torque converter based on the PARSEC function, which can achieve the shaping of the hydrodynamic torque converter with a large bending degree, high continuity, adjustment of a wide power spectrum range, and simple and rapid design.

[0007] Technical solution

[0008] To achieve the above purpose, the present invention provides a method for shaping the blades of a hydrodynamic torque converter based on the PARSEC function. This method introduces the PARSEC function into the blade profile design of the hydrodynamic torque converter, uses the PARSEC function to design the backbone curve of the unit blade, the pressure surface thickness distribution curve of the blade, and the suction surface thickness distribution curve of the blade, and then thickens the backbone curve respectively to obtain the two-dimensional unit blade profile curve; when the pressure surface thickness distribution curve and the suction surface thickness distribution curve of the blade are the same, a symmetric two-dimensional blade profile is obtained. In addition, the PARSEC method can also construct an asymmetric blade profile. By analyzing the required asymmetric blade profile and then adjusting the blade thickness factor to adjust the blade thickness, the peak position and height of the unit blade thickness distribution are adjusted, thereby performing local adjustment of the blade thickness distribution. Then, different thickness distribution curves are superimposed on the same backbone curve to obtain an asymmetric two-dimensional blade profile. Then, by performing operations such as rotation, scaling, and mirroring on the nodes of the unit blade profile line, the true two-dimensional blade profile curve is obtained, and the relationship between the control parameters of the unit blade backbone curve (blade inlet angle α in , blade outlet angle α out , peak height y of the blade backbone curve g * and peak position x of the blade backbone curve g * ) and the PARSEC curve is established; the relationship between the control parameters of the unit blade thickness distribution (leading edge radius h of the blade thickness R1 , trailing edge radius h of the blade thickness R2 , peak height h of the blade thickness * and peak position x of the blade thickness h * ) and the PARSEC curve is established; by adjusting the control parameters of the blade, precise adjustment of the unit backbone curve and thickness distribution curve of the blade can be achieved, thereby fully parameterizing the entire blade design and facilitating the precise design of the blade.

[0009] The airfoil curve designed by the PARSEC curve cannot be directly used for the design of the impeller blades of a torque converter. The airfoil curve designed by PARSEC has the characteristics of a blunt head and a pointed tail. The impeller blades of a torque converter must have the characteristics of a blunt head and a blunt tail to enable good blade casting and ensure the strength of the blades. Therefore, in the present invention, the trailing edge curve of the PARSEC curve is used for the design of the impeller blade backbone curve of the torque converter, and the leading edge curve of the PARSEC curve is used for the design of the impeller blade thickness distribution curve, thus fully applying the technical advantages of the PARSEC curve and achieving the efficient parametric design of the impeller blades of the torque converter.

[0010] A method for shaping the impeller blades of a torque converter based on the PARSEC function provided by the present invention includes the following steps:

[0011] Step 1: Specify the circular curve of the torque converter. The circular curve of the torque converter includes the inner ring curve, the outer ring curve, and the axial plane projection of the inlet and outlet edges of the blades in the circular view of the torque converter.

[0012] Step 2: Specify the control parameters of the unit blade backbone curve. The polynomial coefficients of the two segments of the unit blade backbone curve are obtained by the PARSEC method from the control parameters of the unit blade backbone curve, and then the two curves are spliced together through mirroring, translation, and scaling operations.

[0013] Step 3: Specify the control parameters of the unit blade thickness distribution. The control parameters of the unit blade thickness distribution are related to the PARSEC function to obtain the polynomial coefficients of the two segments of the unit blade thickness distribution curve, and then the two curves are spliced together through mirroring, translation, and scaling operations to obtain the complete unit blade thickness distribution curve.

[0014] Step 4: Superimpose the unit blade thickness distribution curve in the normal direction of the unit blade backbone curve to obtain the two-dimensional unit airfoil curve; the derivative of each point is obtained by differentiating the unit blade backbone curve, and the slope of the normal line of the backbone curve at each sub-point is obtained through the relationship that the derivative of each point and the slope of the normal line are perpendicular to each other. The height of the corresponding sub-point of the true blade thickness distribution curve is superimposed on the normal line at this sub-point, and finally the coordinates of the pressure surface and the suction surface of the two-dimensional blade are obtained.

[0015] Step 5: Rotate and scale the suction surface, pressure surface, and backbone of the two-dimensional unit blade into the true two-dimensional airfoil, and then obtain the three-dimensional curve of the blade through a generalized conformal transformation mapping. The final three-dimensional curved impeller blades of the torque converter are obtained through ruled surface and stitching operations.

[0016] Further, in Step 1, the design parameters of the torque converter circular curve include the effective diameter D, the minimum diameter d, and the circular curve width B of the torque converter; by the three-arc method, the radii r1 and r3 of the first and third arcs of the outer circular curve can be obtained, and the centers of the first and third arcs are on the symmetry center line. Then, the second arc can be obtained according to its tangency with the first and third arcs, that is:

[0017]

[0018] Among them, N represents the diameter ratio, N = d / D.

[0019] Further, in Step 2, the first-stage unit blade camber line is constructed using the PARSEC function, and the curve equation of the first-stage unit blade camber line is as follows:

[0020]

[0021] Among them, y g1 is the ordinate of the unit blade camber line, x g1 is the abscissa of the blade along the chord direction, a n is the polynomial coefficient; in order to solve the coefficient, 5 control parameters need to be given, which are the leading-edge radius R le of the unit blade camber line, the peak position x g * of the blade camber line, the peak height y g * of the blade camber line, the curvature 1 / ρ at the peak of the blade camber line, and the blade outlet angle α out ; the system of equations for solving the polynomial coefficients of the first-stage unit blade camber line is shown as follows:

[0022]

[0023] Among them, a1 to a6 are the coefficients in the system of equations of the first-stage unit blade camber line, 1 / ρ1 and R le1 are given constants, so there are:

[0024]

[0025] The first-stage unit blade camber line has the following conditions at the right endpoint:

[0026]

[0027] Similarly, the second-stage unit blade camber line is also constructed using the PARSEC function, and the curve equation of the second-stage unit blade camber line is as follows:

[0028]

[0029] The system of equations for solving the polynomial coefficients of the second-stage unit blade camber line is shown as follows:

[0030]

[0031] Among them, a7 to a 12 are the coefficients in the equations of the camber line of the second-stage unit blade, 1 / ρ2 and R le2 are given constants. Therefore, there is:

[0032]

[0033] The camber line of the second-stage unit blade has the following conditions at the right endpoint:

[0034]

[0035] The camber lines of the two-stage unit blades have the following relationship at the coordinate point (x g *, y g *):

[0036]

[0037] Retain the part of the camber line of the first-stage blade unit where x g1 * < x g1 < 1, and retain the part of the camber line of the second-stage blade unit where x g1 * < x g2 < 1; then, after symmetrically reflecting the part of the camber line of the second-stage blade unit where x g1 * < x g2 < 1 about x = 1, translate it, and after scaling by the scaling factor, splice it with the part of the camber line of the first-stage blade unit where x g1 * < x g1 < 1 to obtain the designed complete camber line of the unit blade, that is:

[0038]

[0039] Furthermore, in step 3, the thickness distribution curve of the first-stage unit blade is constructed using the PARSEC function. Therefore, the curve equation of the thickness distribution curve of the first-stage unit blade is as follows:

[0040]

[0041] Among them, h1 is the ordinate of the thickness distribution curve of the unit blade, x h is the abscissa of the thickness distribution curve of the unit blade, b n is the polynomial coefficient; in order to solve for the coefficients, 5 control parameters are required, namely the leading-edge radius R le of the thickness distribution of the unit blade, the peak position x h * of the thickness distribution, the peak height h* of the thickness distribution, the curvature 1 / ρ at the peak of the thickness distribution, and the exit wedge angle β out; To reflect the superposition of different thicknesses on the same bone line, denote the thickness of the pressure surface formed by superposition as h u , and the thickness of the suction surface formed by superposition as h d , and they can both be solved by solving the system of equations for the polynomial coefficients of the unit blade thickness distribution, as shown in the following formula:

[0042]

[0043] where, b1~b6 are the coefficients in the system of equations for the unit blade thickness distribution curve; 1 / ρ1 and β out1 are given constants, so there are:

[0044]

[0045] The first-segment unit blade thickness distribution curve has the following conditions at the left endpoint:

[0046]

[0047] At the same time, the radius of curvature of the first-segment unit blade thickness distribution curve at the point (0, 0) satisfies the following relationship:

[0048]

[0049] Similarly, the second-segment unit blade thickness distribution curve is also constructed using the PARSEC curve, and the equation of the second-segment unit blade thickness distribution curve is as follows:

[0050]

[0051] The system of equations for solving the polynomial coefficients of the second-segment unit blade thickness distribution curve is shown in the following formula:

[0052]

[0053] where, b7~b 12 are the coefficients in the system of equations for the unit blade thickness distribution curve; 1 / ρ2 and β in2 are given constants, so there are:

[0054]

[0055] The second-segment unit blade thickness distribution curve has the following conditions at the left endpoint:

[0056]

[0057] At the same time, the radius of curvature of the second-segment unit blade thickness distribution curve at the point (0, 0) satisfies the following relationship:

[0058]

[0059] The thickness distribution curves of the two-segment unit blades have the following relationship at the thickness peak (x h *, h*):

[0060]

[0061] Retain the part of the thickness distribution curve of the first-segment unit blade where 0 < x h1 < x h1 *, and retain the part of the thickness distribution curve of the second-segment unit blade where 0 < x h2 < x h1 *; then translate the part of the thickness distribution curve of the second-segment unit blade where 0 < x h2 < x h1 * to the right by a distance of 1, scale it by the scaling factor, and finally symmetricize it about x h = 1, and splice it with the part of the thickness distribution curve of the first-segment unit blade where 0 < x h1 < x h1 * to obtain the complete thickness distribution curve of the unit blade:

[0062]

[0063] Furthermore, in step 4, there is a perpendicular relationship between the tangents and the outer normals of the respective points on the unit blade bone line. From this, the slope of the outer normal can be obtained. The slope of the tangent of the blade bone line is the first derivative of the blade bone line. The expressions for the tangent of the bone line and the outer normal are as follows:

[0064]

[0065] where α g is the angle corresponding to the tangent slope of each point on the unit blade bone line, and α h is the angle between the outer normal of the bone line and the horizontal line; by superimposing the unit blade thickness distribution curve and the unit blade bone line, a complete unit two-dimensional blade profile is obtained. Denote the coordinates of the suction surface of the blade profile as (x d , y d ), and the coordinates of the pressure surface of the blade profile as (x u , y u ).

[0066] Furthermore, when constructing an asymmetric blade through the PARSEC function, by analyzing the asymmetric blade to be obtained, and then adjusting the blade thickness by adjusting the blade thickness factor, the peak position and height of the unit blade thickness distribution are adjusted, thereby making a local adjustment of the blade thickness distribution. Then, by superimposing different thickness distribution curves on the same bone line, an asymmetric two-dimensional blade profile curve is obtained;

[0067] The coordinate equations of the pressure surface and suction surface of the unit two-dimensional blade profile with different thickness superpositions are as follows:

[0068]

[0069] Furthermore, in step 5, the real two-dimensional blade profile curve is obtained by rotating and scaling the two-dimensional unit blade profile; the transformation from the two-dimensional unit blade profile to the real two-dimensional blade profile curve is as follows:

[0070]

[0071] In the formula, θ is the rotation angle, L is the length of the inner and outer ring curves intercepted by the inlet and outlet edges of the blade in the circular view of the circulation circle, (S u , L u ) are the coordinate of the pressure surface curve of the real two-dimensional blade profile, (S d , L d ) are the coordinate of the suction surface curve of the real two-dimensional blade profile.

[0072] Beneficial technical effects

[0073] Compared with the prior art, the present invention introduces the PARSEC function curve into the blade profile design of the hydraulic torque converter, uses the PARSEC function to design the two-dimensional unit blade backbone line and the blade thickness distribution curve, obtains the two-dimensional real blade profile by rotating and scaling the two-dimensional unit blade profile line, etc., and expresses the whole blade in a fully parametric way, which is convenient for the precise design of the blade; at the same time, using the PARSEC parametric curve for blade design solves the defects of inaccurate and cumbersome traditional hydraulic torque converter blade profile design, and greatly improves the transmission performance of the hydraulic torque converter.

[0074] Specifically, a parametric design method for the blades of a hydraulic torque converter based on the PARSEC function proposed by the present invention has the following prominent advantages compared with the traditional torque converter blade profile design method:

[0075] (1) There are many adjustable parameters for the blade; there are many adjustable control parameters for the backbone line of the blade unit and the unit thickness distribution curve. Adjusting the peak height and peak position of the blade backbone line can realize the adjustment of the blade bending degree and the blade bending position; at the same time, the deviation degree between the blade backbone line and the radial reference line can be adjusted to realize the adjustment of the blade inclination degree. Compared with the blades of traditional hydraulic torque converters, there are more control parameters for the blade profile adjustment freedom.

[0076] (2) The blade design is applicable to multiple situations; the PARSEC method can be used to design both symmetric and asymmetric blades. When designing symmetric blades, for the upper and lower profiles of two-dimensional unit blades, a single thickness curve can be used to superimpose on the unit backbone curve, thus obtaining a two-dimensional unit airfoil with symmetric upper and lower surfaces. Additionally, the PARSEC method can also construct asymmetric blades. By analyzing the desired asymmetric blade and adjusting the blade thickness factor, the thickness of the blade can be adjusted, achieving the adjustment of the peak position and height of the unit blade thickness distribution, thereby locally adjusting the blade thickness distribution. Then, different thickness distribution curves are superimposed on the same backbone curve to obtain an asymmetric two-dimensional blade; this is a major feature of the present invention.

[0077] (3) The continuity of the blade curve is good; the PARSEC method gives the blade curve designed by the present invention a high-order derivative, which is more in line with the design concept of a streamlined blade compared to the traditional hydrodynamic torque converter blade, can reduce flow resistance, lower hydraulic losses, and is more in line with the green blade design; while using the splicing method can eliminate the bending of the leading edge of the blade backbone curve (large curvature change) caused by the leading edge radius in the blade unit backbone curve constructed by the PARSEC curve and add the trailing edge radius to the rear end of the unit blade thickness distribution curve, thereby increasing the strength of the blade and improving its castability, achieving the design of the blade using the PARSEC method and making improvements according to requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute a limitation to the present invention.

[0079] Figure 1 is a flowchart for the parametric construction of the hydrodynamic torque converter blade;

[0080] Figure 2 is the design of the circulating circle of the hydrodynamic torque converter;

[0081] Figure 3 is the original blade unit backbone curve designed using the PARSEC method;

[0082] Figure 4 is the original blade thickness distribution curve designed using the PARSEC method

[0083] Figure 5 is the required hydrodynamic torque converter unit blade backbone curve after splicing;

[0084] Figure 6 is the required hydrodynamic torque converter unit blade thickness distribution curve (pressure side thickness and suction side thickness) after splicing;

[0085] Figure 7 It is a two-dimensional unit blade profile structure diagram of a hydrodynamic torque converter (superposition of the unit blade backbone curve, pressure surface thickness, and suction surface thickness);

[0086] Figure 8 It is the design of the pressure surface of the real blade in two dimensions of the hydrodynamic torque converter (scaling, mirroring, rotation);

[0087] Figure 9 It is the design of the suction surface of the real blade in two dimensions of the hydrodynamic torque converter (scaling, mirroring, rotation);

[0088] Figure 10 It is the three-dimensional blade profile design of the outer ring pressure surface of the hydrodynamic torque converter;

[0089] Figure 11 It is the three-dimensional blade profile design of the outer ring suction surface of the hydrodynamic torque converter;

[0090] Figure 12 It is the three-dimensional blade profile design of the inner ring pressure surface of the hydrodynamic torque converter;

[0091] Figure 13 It is the three-dimensional blade profile design of the inner ring suction surface of the hydrodynamic torque converter;

[0092] Figure 14 It is the three-dimensional solid of the pump impeller blades of the hydrodynamic torque converter;

[0093] In the figure: 1 - The first-segment unit blade backbone curve constructed by the PARSEC method; 2 - The second-segment unit blade backbone curve constructed by the PARSEC method; 3 - The original first-segment unit blade thickness distribution curve constructed by the PARSEC method; 4 - The second-segment unit blade thickness distribution curve constructed by the PARSEC method; 5 - The spliced unit blade backbone curve; 6 - The spliced original unit blade pressure surface thickness distribution curve; 7 - The spliced unit blade suction surface thickness distribution curve; 8 - The upper profile line of the two-dimensional blade; 9 - The lower profile line of the two-dimensional blade; 10 - The pressure surface curve of the real two-dimensional blade; 11 - The suction surface curve of the real two-dimensional blade; 12 - The pressure surface curve in the three-dimensional blade profile; 13 - The suction surface curve in the three-dimensional blade profile; 14 - The outer ring pressure surface curve in the three-dimensional blade; 15 - The outer ring suction surface curve in the three-dimensional blade; 16 - The inner ring pressure surface curve in the three-dimensional blade; 17 - The inner ring suction surface curve in the three-dimensional blade; 18 - The three-dimensional model of the pump impeller blades constructed by the PARSEC method. Detailed implementation manners

[0094] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0095] Those skilled in the art will know that the PARSEC (Parametric Section) function is a parametric function used to describe two-dimensional or three-dimensional curves. It defines the shape of the curve through several key parameters, including the leading-edge radius, trailing-edge radius, maximum thickness position, maximum thickness value, etc. By adjusting these parameters, the shape and characteristics of the curve can be precisely controlled.

[0096] As Figures 1 to 14 shown: A parametric design method for the curved blades of a hydraulic torque converter based on the PARSEC function provided by the present invention has the following core content:

[0097] First, five blade control parameters of the unit skeleton line are given, including the leading-edge radius R of the unit blade skeleton line le (auxiliary design parameter), the peak position x of the blade skeleton line g *, the peak height y of the blade skeleton line g *, the curvature 1 / ρ at the peak of the blade skeleton line, and the blade outlet angle α out . These parameters are related to the PARSEC function to obtain two sections of the unit blade skeleton line. Retain the part of the first section of the blade unit skeleton line where x g1 * < x g1 < 1 and the part of the second section of the blade unit skeleton line where x g1 * < x g2 < 1. The part of the second section of the unit blade skeleton line where x g1 * < x g2 < 1 is symmetrically transformed, translated, and scaled and then spliced with the part of the first section of the unit blade skeleton line where x g1 * < x g1 < 1 at (x g *, y g *) to obtain the designed complete unit blade skeleton line.

[0098] Similarly, five control parameters of the unit thickness distribution curve are given, including the leading-edge radius R of the unit blade thickness distribution le , the peak position x of the thickness distribution h *, the peak height h* of the thickness distribution, the curvature 1 / ρ at the peak of the thickness distribution, and the thickness distribution outlet wedge angle β out (auxiliary design parameter); these parameters are related to the PARSEC function to obtain two sections of the unit thickness distribution curve. Retain the part of the first section of the unit blade thickness distribution curve where 0 < x h1 < x h1 * and the part of the second section of the unit blade thickness distribution curve where 0 < x h2 < x h1 *. Then, the part of the second section of the unit blade thickness distribution curve where 0 < x h2 < x h1The part of * is translated, scaled, and symmetrically operated, and it is combined with the 0 < x of the first-stage unit thickness distribution curve h1 <x h1 The part of * is spliced at (x h *, h*) to obtain the complete unit blade thickness distribution curve.

[0099] Next, through the geometric relationship between the unit blade camber line and the outer normal, the thickness is superimposed on the unit blade camber line to complete the parametric design of the unit blade camber line and the blade thickness distribution curve. At the same time, asymmetric blade profiles can be obtained by constructing different unit thickness distribution curves. Then, the unit blade curve is scaled, mirrored, and rotated to obtain the real 2D blade profile.

[0100] Finally, the 2D blade profile is mapped to the 3D space through conformal transformation, and the 3D blade entity of the torque converter is constructed through operations such as ruled surface and stitching.

[0101] Embodiment

[0102] Since all impellers are designed by this method, only the design of the pump impeller blade is taken as an example below, combined with the appendix Figure 1 The method for designing the torque converter blade based on the PARSEC method is specifically introduced and described in detail.

[0103] Step 1: Design of the torque converter circulating circle (as Figure 2 shown).

[0104] Given the design parameters of the torque converter circulating circle curve, including the known effective diameter D, minimum diameter d, and circulating circle width B of the torque converter, by the three-arc method, the radii r1 and r3 of the first and third arcs of the outer ring of the circulating circle can be obtained, and the centers of the first and third arcs are on the symmetry center line. Then, the second arc can be obtained according to its tangency with the first and third arcs.

[0105]

[0106] Among them, N represents the diameter ratio, N = d / D.

[0107] Step 2: Design of the unit blade camber line (as Figure 3 , Figure 4 shown).

[0108] The first-stage unit blade camber line is constructed using the PARSEC function, and the curve equation of the first-stage unit blade camber line is as follows:

[0109]

[0110] Among them, y g1 is the ordinate of the unit camber line, x g1is the abscissa of the blade along the chord direction, a n is the polynomial coefficient; to solve for the coefficients, 5 control parameters (blade control parameters) need to be given, which are the leading edge radius R of the unit blade camber line le (auxiliary design parameter), the peak position x of the blade camber line g *, the peak height y of the blade camber line g *, the curvature 1 / ρ at the peak of the blade camber line, and the blade outlet angle α out . The system of equations for solving the polynomial coefficients of the first-stage unit blade camber line is shown in Equation (3):

[0111]

[0112] where, a1~a6 are the coefficients in the system of equations for the first-stage unit camber line, 1 / ρ1 and R le1 are given constants and there are:

[0113]

[0114] The first-stage unit blade camber line has the following conditions at the right endpoint:

[0115]

[0116] Similarly, the second-stage unit blade camber line is also constructed using the PARSEC function, and the curve equation of the second-stage unit blade camber line is as follows:

[0117]

[0118] The system of equations for solving the polynomial coefficients of the second-stage unit camber line is shown in Equation (7):

[0119]

[0120] where, a7~a 12 are the coefficients in the system of equations for the second-stage unit camber line, 1 / ρ2 and R le2 are given constants and there are:

[0121]

[0122] The second-stage unit blade camber line has the following conditions at the right endpoint:

[0123]

[0124] The two-stage unit blade camber lines have the following relationship at the coordinate point (x g *, y g *):

[0125]

[0126] Retain the camber line x of the first-stage blade unit g1 *<x g1 Retain the part where <1, and retain the camber line x of the second-stage blade unit g1 *<x g2 <1. Then, symmetricize the camber line x of the second-stage blade unit g1 *<x g2 <1 about x = 1, then translate it 1 unit to the left, and after scaling by the scaling factor, splice it with the camber line x of the first-stage blade unit g1 *<x g1 <1 to obtain the designed complete camber line of the unit blade:

[0127]

[0128] Step 3: Design the thickness distribution of the unit blade (as shown in Figure 5 、 Figure 6 ).

[0129] The thickness distribution curve of the first-stage unit blade is constructed using the PARSEC function. Therefore, the curve equation of the thickness distribution curve of the first-stage unit blade is as follows:

[0130]

[0131] where h1 is the ordinate of the thickness distribution curve of the unit blade, x h is the abscissa of the thickness distribution curve of the unit blade, and b n is the polynomial coefficient. To solve for the coefficients, 5 control parameters (blade thickness distribution control parameters) are also required, namely the leading-edge radius R of the unit blade thickness distribution le 、the peak position x of the thickness distribution h *, the peak height h* of the thickness distribution, the curvature 1 / ρ at the peak of the thickness distribution, and the exit wedge angle β of the thickness distribution out (auxiliary design parameters). To reflect the superposition of different thicknesses on the same camber line, denote the thickness forming the pressure surface by h u , and the thickness forming the suction surface by h d , and they can both be solved by solving the system of equations for the polynomial coefficients of the unit blade thickness distribution, as shown in Equation (13):

[0132]

[0133] where b1~b6 are the coefficients in the system of equations for the thickness distribution curve of the unit blade. 1 / ρ1 and β out1 are given constants and there are:

[0134]

[0135] The first - stage unit blade thickness distribution curve has the following conditions at the left - hand end point:

[0136]

[0137] Meanwhile, the radius of curvature of the first - stage unit blade thickness distribution curve at the point (0, 0) satisfies the following relationship:

[0138]

[0139] Similarly, the second - stage unit blade thickness distribution curve is also constructed using the PARSEC curve. The equation of the second - stage unit blade thickness distribution curve is as follows:

[0140]

[0141] The system of equations for solving the polynomial coefficients of the second - stage unit blade thickness distribution curve is shown in Equation (18):

[0142]

[0143] where b7~b 12 are the coefficients in the system of equations of the unit blade thickness distribution curve. 1 / ρ2 and β in2 are given constants. Therefore, we have:

[0144]

[0145] The second - stage unit blade thickness distribution curve has the following conditions at the left - hand end point:

[0146]

[0147] Meanwhile, the radius of curvature of the second - stage unit blade thickness distribution curve at the point (0, 0) satisfies the following relationship:

[0148]

[0149] The two - stage unit blade thickness distribution curves have the following relationship at the blade thickness peak (x h *, h*):

[0150]

[0151] Retain the part of the first - stage unit blade thickness distribution curve where 0 < x h1 < x h1 *. Retain the part of the second - stage unit blade thickness distribution curve where 0 < x h2 < x h1 *. Then, for the second - stage unit blade thickness distribution curve where 0 < x h2 < x h1The part of * is translated 1 unit to the right, scaled by the scaling factor, and finally symmetric about x h = 1. Then splice it with the part of 0 < x of the first-stage unit thickness distribution curve h1 <x h1 * to obtain the complete unit blade thickness distribution curve:

[0152]

[0153] Step 4: Perform thickness superposition on the obtained camber line to obtain the suction surface and pressure surface of the unit blade (as Figure 7 shown).

[0154] There is a perpendicular relationship between the tangents and outer normals of the points on the camber line of the unit blade. In this way, the slope of the outer normal can be obtained. The slope of the camber line tangent is the first derivative of the camber line. The expressions of the camber line tangent and the outer normal are as follows:

[0155]

[0156] where a g is the angle corresponding to the tangent slope of each point on the camber line of the unit blade, and a h is the angle between the outer normal of the camber line and the horizontal line. By superposing the unit blade thickness curve and the unit blade camber line, a complete unit two-dimensional airfoil is obtained. Denote the coordinates of the suction surface of the airfoil as (x d , y d ), and the coordinates of the pressure surface of the airfoil as (x u , y u ).

[0157] The coordinate equations of the suction surface and pressure surface of the unit two-dimensional airfoil are:

[0158]

[0159] Step 5: Design the three-dimensional blade entity.

[0160] Obtain the true two-dimensional airfoil curve (camber line, pressure surface curve, and suction surface curve) by rotating and scaling the unit two-dimensional airfoil. As Figure 8 , Figure 9 shown, the transformation from the unit two-dimensional airfoil to the true two-dimensional airfoil curve is as follows:

[0161]

[0162] where θ is the rotation angle, L is the length of the inner and outer ring curves intercepted by the inlet and outlet edges of the blade in the circular view of the circulation circle, (S u , L u ) are the coordinates of the pressure surface of the true two-dimensional airfoil, and (S d , L d) are the coordinates of the suction surface of the real two-dimensional blade profile.

[0163] After being mapped by the generalized conformal transformation, the curves of the pressure surface and the suction surface of the outer ring and the curves of the pressure surface and the suction surface of the inner ring of the three-dimensional blade profile as shown in Figures 10 to 13 are obtained respectively. Finally, through steps such as ruled surface and stitching, the three-dimensional blade as shown in Figure 14 is obtained.

[0164] Finally, it should be noted that specific examples are used in this article to elaborate on the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention. Without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A method for modeling a hydraulic torque converter blade based on a PARSEC function, characterized in that: The PARSEC function is used to design the unit blade skeleton, the blade pressure surface thickness distribution curve and the blade suction surface thickness distribution curve, and then the skeleton is thickened to obtain a two-dimensional unit blade profile curve; then the nodes of the unit blade profile are rotated, scaled and mirrored to obtain the real two-dimensional blade profile curve, and the relationship between the unit blade skeleton control parameters, the unit blade thickness distribution control parameters and the PARSEC curve is established. By adjusting the blade control parameters, the unit skeleton and thickness distribution curve of the blade can be adjusted, thereby fully parametrically expressing the entire blade design.

2. The method for modeling a hydraulic torque converter blade based on PARSEC function according to claim 1, characterized in that: The following steps are involved: Step 1: Given a torque converter circulation circle curve, the circulation circle curve includes an inner ring curve, an outer ring curve, and the axial projection of the blade inlet and outlet edges on the circulation circle view; Step 2: Given the unit blade bone line control parameters, the polynomial coefficients of the two segments of the unit blade bone line are obtained by the unit blade bone line control parameters through the PARSEC method, and then the two segments of the curve are spliced ​​together through mirroring, translation, and scaling operations; Step 3: Given the control parameters of the unit blade thickness distribution, the blade thickness distribution control parameters are linked to the PARSEC function to obtain the polynomial coefficients of the two segments of the unit blade thickness distribution curves, and then the two segments of the curves are spliced ​​together through mirroring, translation, and scaling operations to obtain a complete unit blade thickness distribution curve; Step 4: Superimpose the unit blade thickness distribution curve on the unit blade bone line normal to obtain a two-dimensional unit blade profile curve; obtain the derivative of each point by deriving the unit blade bone line curve, and then calculate the slope of the bone line normal at each point through the relationship that the derivative of each point and the normal slope are perpendicular to each other, and superimpose the height of the corresponding point of the real blade thickness distribution curve on the normal line of the point, and finally obtain the coordinates of the pressure surface and suction surface of the two-dimensional blade; Step 5: The suction surface, pressure surface and bone line of the two-dimensional unit blade are rotated and scaled into a real two-dimensional blade shape, and then mapped through generalized angle-preserving transformation to obtain the three-dimensional space curve of the blade. The final three-dimensional curved blade of the torque converter is obtained through straight line and stitching operations.

3. The method for modeling a hydraulic torque converter blade based on a PARSEC function according to claim 2, characterized in that: In step 1, the design parameters of the torque converter circulation circle curve include the torque converter effective diameter D, the minimum diameter d and the circulation circle width B; by the three-arc method, the radii r1 and r3 of the first and third arcs of the outer ring curve of the circulation circle can be obtained, and the centers of the first and third arcs are on the symmetric center line, and then the second arc can be obtained based on its tangency with the first and third arcs, that is: Here, N represents the diameter ratio, N=d / D.

4. The method for modeling a hydraulic torque converter blade based on a PARSEC function according to claim 2, characterized in that: In step 2, the first section of the unit leaf skeleton is constructed using the PARSEC function, and the curve equation of the first section of the unit leaf skeleton is as follows: Among them, y g1 is the ordinate of the unit blade bone line, x g1 is the horizontal coordinate of the blade along the chord direction, a n are the polynomial coefficients; in order to solve the coefficients, five control parameters need to be given, namely, the leading edge radius R of the unit blade bone line le , blade bone line peak position x g *, blade bone line peak height y g *, the curvature 1 / ρ at the peak of the blade bone line, and the blade outlet angle α out ; The equations for solving the polynomial coefficients of the first segment of the unit blade bone line are as follows: Among them, a1~a6 are the coefficients of the first section of the unit blade bone line equation group, 1 / ρ1 and R le1 is a given constant, so: The first segment of the unit blade bone line has the following conditions at the right endpoint: Similarly, the second section of the unit blade skeleton is also constructed using the PARSEC function. The curve equation of the second section of the unit blade skeleton is as follows: The equations for solving the polynomial coefficients of the second-segment blade bone line are as follows: Among them, a7~a 12 are the coefficients of the second-segment blade bone equations, 1 / ρ2 and R le2 is a given constant, so: The second segment of the unit blade bone line has the following conditions at the right endpoint: The two-segment blade bone line is at the coordinate point (x g *,y g *) has the following relationship: Keep the first blade unit bone line x g1 * <x g1 <1, retain the second segment blade unit bone line x g1 * <x g2 <1; then the second section unit leaf bone line x g1 * <x g2 The part < 1 is symmetrical about x = 1, and then translated, and scaled by the scaling factor to match the first segment of the unit leaf bone line x g1 * <x g1 The designed complete unit blade skeleton can be obtained by splicing the parts <1, that is:

5. The method for modeling a hydraulic torque converter blade based on a PARSEC function according to claim 2, characterized in that: In step 3, the first section of the unit leaf thickness distribution curve is constructed using the PARSEC function, so the curve equation of the first section of the unit leaf thickness distribution curve is as follows: Among them, h1 is the ordinate of the unit leaf thickness distribution curve, x h is the abscissa of the unit blade thickness distribution curve, b n are the polynomial coefficients; in order to solve the coefficients, five control parameters are needed, namely the leading edge radius R of the unit blade thickness distribution le , thickness distribution peak position x h *, thickness distribution peak height h*, curvature 1 / ρ at the thickness distribution peak and thickness distribution exit wedge angle β out ; In order to reflect the different thicknesses superimposed on the same bone line, the thickness of the superimposed pressure surface is denoted as h u , the thickness of the superimposed suction surface is h d , which can be solved by solving the equations of the unit blade thickness distribution polynomial coefficients, as shown in the following equations: Among them, b1~b6 are the coefficients in the unit blade thickness distribution curve equation group; 1 / ρ1 and β out1 is a given constant, so: The first section of the unit blade thickness distribution curve has the following conditions at the left endpoint: At the same time, the radius of curvature of the first section unit blade thickness distribution curve at point (0, 0) satisfies the following relationship: Similarly, the second section unit leaf thickness distribution curve is also constructed using the PARSEC curve, and the equation of the second section unit leaf thickness distribution curve is as follows: The equations for solving the polynomial coefficients of the second segment unit blade thickness distribution curve are as follows: Among them, b7~b 12 are the coefficients in the equations for the unit blade thickness distribution curve; 1 / ρ2 and β in2 is a given constant, so: The second section of the unit blade thickness distribution curve has the following conditions at the left endpoint: At the same time, the radius of curvature of the second section unit blade thickness distribution curve at point (0, 0) satisfies the following relationship: The thickness distribution curve of the two-segment unit blade is at the thickness peak (x h *, h*) have the following relationship: Keep the first section unit blade thickness distribution curve 0 <x h1 <x h1 * The part retains the second segment unit leaf thickness distribution curve 0 <x h2 <x h1 * part; then the second segment unit blade thickness distribution curve 0 <x h2 <x h1 The * part is translated to the right by a distance of 1, and then scaled by the scaling factor. h = 1 to be symmetrical and to be compared with the 0 of the first section unit blade thickness distribution curve <x h1 <x h1 The complete unit blade thickness distribution curve can be obtained by splicing the parts with *:

6. The method for modeling a hydraulic torque converter blade based on a PARSEC function according to claim 2, characterized in that: In step 4, the tangents and the external normals of each point on the unit blade bone line are perpendicular to each other, from which the slope of the external normal can be obtained. The slope of the blade bone line tangent is the first-order derivative of the blade bone line. The expressions of the bone line tangent and the external normal are as follows: Among them, α g is the angle of the tangent slope corresponding to each point of the unit blade bone line, α h is the angle between the outer normal of the bone line and the horizontal line; by superimposing the unit blade thickness distribution curve and the unit blade bone line, the complete unit two-dimensional blade shape is obtained, and the blade suction surface coordinate is recorded as (x d ,y d ), the blade pressure surface coordinates are (x u ,y u ).

7. The method for modeling a hydraulic torque converter blade based on a PARSEC function according to claim 6, characterized in that: When constructing asymmetric blades through the PARSEC function, the desired asymmetric blades are analyzed, and then the blade thickness is adjusted by adjusting the blade thickness factor, so as to adjust the peak position and height of the unit blade thickness distribution, thereby making local adjustments to the blade thickness distribution, and then superimposing different thickness distribution curves on the same bone line to obtain an asymmetric two-dimensional blade curve; The coordinate equations of the pressure and suction surfaces of the two-dimensional blades with different thicknesses are:

8. The method for modeling a hydraulic torque converter blade based on a PARSEC function according to claim 2, characterized in that: In step 5, the real two-dimensional blade profile curve is obtained by rotating and scaling the two-dimensional unit blade profile; the transformation from the two-dimensional unit blade profile to the real two-dimensional blade profile curve is as follows: Where θ is the rotation angle, L is the length of the inner and outer ring curves intercepted by the inlet and outlet edges of the blade on the circular view, (S u , L u ) is the curve coordinate of the pressure surface of the real two-dimensional blade, (S d , L d ) is the curve coordinate of the suction surface of the real two-dimensional blade.

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