A method for designing a single pivot flexible wall nozzle profile curve

Abstract

The application discloses a single fulcrum flexible wall nozzle profile curve design method. The method comprises the following steps: obtaining design parameters and a target profile curve of a single fulcrum flexible wall nozzle; determining initial values of support rod parameters according to the design parameters; writing a profile curve calculation program by using MAPLE software, inputting the design parameters and the initial values of the support rod parameters into the profile curve calculation program, and calculating the profile curve; subtracting the target profile curve from the profile curve to obtain a profile curve deviation; when the profile curve deviation is greater than a maximum profile curve deviation, adjusting the numerical values of the support rod parameters according to the profile curve deviation, repeatedly performing iterative calculation by using the MAPLE software, and obtaining the profile curve deviation between the profile curve and the target profile curve being less than the maximum profile curve deviation until the profile curve is obtained. The application does not use a finite element modeling simulation process, has the advantage of short design period, and guarantees the solving precision through elliptic integral solving derived according to the Euler-Bernoulli beam large deformation theory.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of single-support-point flexible-wall nozzle design in a wind tunnel, and particularly relates to a single-support-point flexible-wall nozzle profile curve design method. BACKGROUND

[0002] A nozzle is an important component of a transonic wind tunnel, and its function is to adjust the flow rate of fluid to a specific Mach number for test and test. The traditional nozzle is designed to be an upper and lower symmetrical streamlined thin wall, and the wall surface of the nozzle cannot be deformed. For each Mach number flow rate working condition, there is a specific nozzle corresponding thereto, and the corresponding nozzle needs to be replaced before the test, which brings many inconveniences to the test. In order to solve this drawback, improve the test efficiency and the test environment, a technology of adjusting the Mach number by relying on the deformation or movement of the nozzle itself gradually appears. This technology can continuously adjust the Mach number, and only one nozzle can provide fluid of multiple Mach numbers. There are many methods to realize the variable fluid Mach number nozzle, and the most typical ones are two kinds: one is to place the upper and lower walls asymmetrically, rely on the relative rigid displacement between each other to adjust the caliber of the nozzle, so as to achieve the purpose of adjusting the Mach number, and the schematic diagram of the nozzle is as shown in Figure 1 ; and the other is the design of the upper and lower symmetrical flexible plate, the nozzle itself can be deformed under the action of external load, and the Mach number can be adjusted by adjusting the profile curve of the upper and lower walls, as shown in Figure 2 . The former has very strict requirements for design, because the nozzle itself will not deform, how to design the wall surface and how to move the wall surface becomes extremely critical, the profile of the nozzle must be optimized, the relationship between the relative motion and the Mach number is obtained through complex calculation, and the design difficulty is extremely great. The latter is relatively easy to realize, and becomes the mainstream of nozzle design. The flexible-wall nozzle makes the upper and lower walls symmetrically deform through the joint action of multiple support rods, so as to obtain the target profile curve corresponding to the Mach number. Therefore, only the number and corresponding position of the support rods and the elongation of each support rod need to be given, the design of the nozzle can be completed. The simplest form of the flexible-wall nozzle is a single-support-point flexible-wall nozzle, which deforms the flexible wall through the action of a single support rod, is not only simple to operate, but also high in efficiency, and can quickly adjust the Mach number.

[0003] At present, the methods mainly used for the profile design of single-strut flexible wall nozzle are finite element modeling simulation, empirical formula and engineering simplification. The finite element simulation used in the design of single-strut flexible wall nozzle is a relatively mature method. The most commonly used is computational fluid dynamics software, which is used to solve the flow behavior of fluid and fluid-structure coupling problems. For the analysis of the deformation and stress of the flexible wall, the finite element with solid mechanics module is needed to simulate, such as ABAQUS and ANSYS. Due to the complex structure of the flexible wall nozzle and the many working conditions, and the need for separate modeling for different types of nozzles, regardless of the type of finite element software, a long modeling cycle is needed, and the simplification of the model in the finite element may affect the accuracy of the results. The method commonly used for solving the profile curve of the flexible wall nozzle through theory is the polynomial fitting method. For small deformation problems, linear elasticity theory is directly used, and for large deformation conditions, piecewise linear method or cubic function fitting is used. Although these methods facilitate calculation to some extent, they are obviously inaccurate in predicting the flexible wall nozzle under large deformation conditions. Empirical formula and engineering simplification are based on experience and may be applicable in most cases. However, due to the lack of theoretical guidance, especially when the existing model has not been encountered before, it is easy to have the case that the empirical formula does not match the actual situation. SUMMARY

[0004] The embodiment of the present application provides a single support point flexible wall nozzle profile curve design method, which aims at the long design cycle of the above finite element modeling simulation method and the small precision of the combination method of empirical formula and engineering simplification. Starting from the theory of large deformation beam, the control equation of single support point flexible wall is derived and expressed as an elliptic integral form. The profile curve of the single support point flexible wall nozzle is obtained by solving the elliptic integral equation set. The solving process is realized by using mathematical software MAPLE / MATLAB, achieving the purpose of quickly calculating and designing the profile curve of the single support point flexible wall nozzle.

[0005] In the first aspect, the embodiment of the present application provides a single support point flexible wall nozzle profile curve design method, comprising:

[0006] obtaining the design parameters of the single support point flexible wall nozzle;

[0007] determining the initial value of the strut parameter according to the design parameters;

[0008] obtaining the target profile curve;

[0009] writing a profile curve calculation program by using MAPLE software, substituting the design parameters of the single support point flexible wall nozzle and the initial value of the strut parameter into the profile curve calculation program, and calculating the profile curve;

[0010] subtracting the target profile curve from the profile curve to obtain the profile curve deviation;

[0011] When the profile curve deviation is greater than the maximum profile curve deviation, the strut parameter value is adjusted according to the profile curve deviation, and iterative calculation is repeatedly performed by using the MAPLE software until the profile curve deviation between the profile curve and the target profile curve is less than or equal to the maximum profile curve deviation, and the profile curve of the single-support-point flexible-wall nozzle is obtained.

[0012] In a possible implementation, the obtaining the design parameters of the single-support-point flexible-wall nozzle comprises:

[0013] obtaining the width of the single-support-point flexible-wall nozzle;

[0014] obtaining the length of the single-support-point flexible-wall nozzle;

[0015] obtaining the thickness of the single-support-point flexible-wall nozzle;

[0016] obtaining the elastic modulus of the single-support-point flexible-wall nozzle.

[0017] In a possible implementation, the strut parameter comprises a strut length and a strut elongation.

[0018] In a possible implementation, the writing the profile curve calculation program by using the MAPLE software, and substituting the design parameters of the single-support-point flexible-wall nozzle and the initial parameters of the strut into the profile curve calculation program to calculate the profile curve comprises:

[0019] 1) simplifying the single-support-point flexible-wall nozzle into a single-strut cantilever beam, and obtaining the balance equation of the single-strut cantilever beam in a curve coordinate system according to the Euler-Bernoulli beam large deformation theory:

[0020]

[0021] wherein α is the inclination angle of the single-strut cantilever beam, s is the curve coordinate of the profile curve, M is the bending moment of the single-strut cantilever beam, E is the elastic modulus of the single-support-point flexible-wall nozzle, b is the width of the single-support-point flexible-wall nozzle, and h is the thickness of the single-support-point flexible-wall nozzle.

[0022] 2) expressing the profile curve as a first-type incomplete elliptic integral and a second-type incomplete elliptic integral through the balance equation, and obtaining a formula expression form of the profile curve equation group:

[0023]

[0024] wherein:

[0025] l is the length of the single-strut cantilever beam, F(k, γ) represents the first-type incomplete elliptic integral, E(k, γ) represents the second-type incomplete elliptic integral, f is the interval [γ0, γ sthe first kind of incomplete elliptic integral of the first kind, e is the interval of the profile curve on the surface of [γ0, γ s the second kind of incomplete elliptic integral of the first kind, S0 is the initial value of the strut length, ΔS is the strut elongation, θ is the angle of strut rotation, P is the force of the strut on the cantilever beam, α L is the inclination angle of the right end point of the single strut cantilever beam, k is the modulus of the elliptic integral, γ is the upper limit of the integral;

[0026] 4) Substitute the design parameters of the single support flexible wall nozzle and the initial values of the strut parameters into the profile curve equation set, solve the equation set, and obtain the profile curve.

[0027] In a possible implementation, when the profile curve deviation is greater than the maximum profile curve deviation, the numerical value of the strut parameter is adjusted according to the profile curve deviation, and the MAPLE software is repeatedly used for iterative calculation until the profile curve deviation between the profile curve and the target profile curve is less than the maximum profile curve deviation, and the profile curve of the single support flexible wall nozzle is obtained.

[0028] The maximum profile curve deviation refers to the maximum value of the difference between the calculated profile curve and the target profile curve,

[0029] The maximum profile curve deviation is ε, and the value range of ε is set to 0.1-0.5mm,

[0030] y i and respectively represent the longitudinal coordinate values of the calculated profile curve and the target profile curve, the profile curve deviation is the difference between the coordinate values, and if:

[0031]

[0032] The strut elongation is reduced by

[0033]

[0034] If

[0035]

[0036] The strut elongation is increased by

[0037]

[0038] The strut adjustment parameter value is substituted into the MAPLE software for iterative calculation again, and the above strut parameter value adjustment and MAPLE software iterative calculation are repeatedly performed until the profile curve deviation is less than the maximum profile curve deviation, and the profile curve of the single support flexible wall nozzle is obtained.

[0039] In a possible implementation, when the profile curve deviation is greater than the maximum profile curve deviation, the value of the strut parameter is adjusted according to the profile curve deviation, and the MAPLE software is repeatedly used for iterative calculation until the profile curve deviation between the profile curve and the target profile curve is less than the maximum profile curve deviation, and the single-support-point flexible-wall nozzle profile curve is obtained, including:

[0040] The maximum profile curve deviation refers to the maximum value of the difference between the calculated profile curve and the target profile curve,

[0041] The maximum profile curve deviation is ε, and the value range of ε is set to 0.1-0.5 mm,

[0042] y i and The longitudinal coordinate values of the calculated profile curve and the target profile curve are represented by y and y, respectively, N is the number of data points, the profile curve deviation is the root mean square deviation R, and then

[0043]

[0044] If R>ε

[0045] The strut elongation is adjusted, that is, the strut adjustment parameter is substituted into the MAPLE software again for iterative calculation. If the R value becomes larger after the strut is adjusted to be elongated, the strut elongation needs to be reduced, and the MAPLE software iterative calculation is repeated. If the R value becomes larger after the strut is adjusted to be shortened, the strut elongation needs to be adjusted, and the MAPLE software iterative calculation is performed until R<ε is satisfied, and the single-support-point flexible-wall nozzle profile curve is obtained.

[0046] In the above embodiments of the present application, under the premise that the geometric parameters and mechanical parameters of the flexible wall in the given flexible-wall nozzle, the target profile curves corresponding to different Mach number fluids, and the initial parameters of the strut are given, the control equation of the profile curve is derived from the theory of large deformation beam, and is expressed as an elliptic integral form. The above known parameters are substituted into the elliptic integral equation set to obtain the profile curve of the single-support-point flexible-wall nozzle. The profile curve is compared with the target profile curve, and the profile curve is greater than the maximum profile curve deviation. The iterative calculation of the profile curve is performed to obtain the single-support-point flexible-wall nozzle profile curve. The present application does not use the process of finite element modeling simulation. Only the parameters of the flexible-wall nozzle need to be provided, and the program can give the profile curve and the profile curve deviation in a very short time, which greatly shortens the design cycle. The elliptic integral solution is obtained through strict theoretical derivation, which provides theoretical guarantee and ensures the solution accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0048] Figure 1 is a schematic diagram of an asymmetric adjustable fluid Mach number nozzle in a supersonic wind tunnel;

[0049] Figure 2 is a schematic diagram of a symmetric adjustable fluid Mach number flexible wall nozzle in a supersonic wind tunnel;

[0050] Figure 3 is a schematic diagram of a single support point flexible wall nozzle in a supersonic wind tunnel;

[0051] Figure 4 is a schematic diagram of a single support point flexible wall nozzle in a supersonic wind tunnel;

[0052] Figure 5 is a schematic diagram of a single support point flexible wall nozzle in a supersonic wind tunnel;

[0053] Figure 6 is a schematic diagram of a single support point flexible wall nozzle in a supersonic wind tunnel; DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0055] The embodiment of the present application provides a single support point flexible wall nozzle profile curve design method, which does not need modeling, and uses elliptic integral and mathematical software MAPLE software to quickly and accurately obtain the single support point flexible wall nozzle profile curve through solving and iteration.

[0056] Referring to Figure 6 The flowchart of the single support point flexible wall nozzle profile curve design method provided by the embodiment of the present application is shown in the figure, which can include the following steps:

[0057] Step 101, obtaining the design parameters of the single support point flexible wall nozzle.

[0058] Specifically, obtaining the design parameters of the single support point flexible wall nozzle includes:

[0059] obtaining a width b of the single-support flexible-wall nozzle;

[0060] obtaining a length L of the single-support flexible-wall nozzle;

[0061] obtaining a thickness h of the single-support flexible-wall nozzle;

[0062] obtaining an elastic modulus E of the single-support flexible-wall nozzle.

[0063] At the beginning of the design of the wind tunnel, according to the design requirements of the wind tunnel, the design parameters of the single-support flexible-wall nozzle are obtained, and the design parameters specifically include: the width b of the single-support flexible-wall nozzle, the length L of the single-support flexible-wall nozzle, the thickness h of the single-support flexible-wall nozzle and the elastic modulus E of the single-support flexible-wall nozzle. In this embodiment, the specific values of the parameters of the single-support flexible-wall nozzle are as follows: L is 200 mm, b is 20 mm, h is 1 mm, and E is 2.5 GPa.

[0064] Step 102, determining the initial value of the strut parameter according to the design parameter; according to the design parameter, the initial value of the strut parameter is obtained, and specifically, the strut parameter includes the strut length S0 and the strut elongation ΔS. In this embodiment, the specific values of the strut parameter are as follows: S0 is 100 mm, and ΔS is 220 mm.

[0065] Step 103, obtaining the target profile curve. According to the Mach number output by the design, the target profile curve is calculated and obtained.

[0066] Step 104, using the MAPLE software to write a profile curve calculation program, substituting the design parameters of the single-support flexible-wall nozzle and the initial parameters of the strut parameter into the profile curve calculation program, and calculating the profile curve; the single-support flexible-wall nozzle is reasonably simplified, and a mechanical model is abstracted, which is finally simplified as a single-strut cantilever beam, as shown in Figure 4 and Figure 5 The single-strut cantilever beam model is reasonably abstracted from the single-support flexible-wall nozzle, so the properties of the elastic material of the single-support flexible-wall nozzle are also embodied on the properties of the single-strut cantilever beam model, that is, the single-strut cantilever beam model has the properties of the elastic material, and the camber of the single-strut cantilever beam model is expressed as the profile curve of the single-support flexible-wall nozzle. The deflection expression of the single-strut cantilever beam model needs to be solved in the framework of the Euler-Bernoulli beam of linear elastic material and geometric nonlinearity, and the control equation obtained by the basic equation of elasticity is finally transformed into an elliptic integral form. Therefore, the profile curve of the single-support flexible-wall nozzle also needs to be solved in the framework of the Euler-Bernoulli beam of linear elastic material and geometric nonlinearity, and the control equation obtained by the basic equation of elasticity is finally transformed into an elliptic integral form. The calculation program of the profile curve is written on the MAPLE software by using the above principle. The design parameters of the single-support flexible-wall nozzle and the initial parameters of the strut parameter are substituted into the calculation program of the profile curve to calculate the profile curve. The specific formula derivation is as follows:

[0067] The flexible wall of the flexible wall nozzle is considered as a cantilever beam, the right end of which is hinged to a strut, the other end of which is hinged and fixed. The flexible wall is mainly curved, the influence of shear force and the change of length can be ignored, and it is a typical Euler-Bernoulli beam. In order to ensure the safe and normal operation of the nozzle, the deformation must be controlled within the elastic range. This problem is considered as a geometrically nonlinear problem of the linear elastic Euler beam. As long as this problem is solved, the design problem of the flexible wall nozzle profile curve can be solved.

[0068] After the flexible wall nozzle is simplified as a cantilever beam, the mechanical model of the cantilever beam is obtained as shown in Figure 4 and Figure 5 The equilibrium equation of the cantilever beam is expressed in the curvilinear coordinate system as follows:

[0069]

[0070] Wherein, α is the inclination angle of the single-strut cantilever beam, s is the profile curve coordinate, M is the bending moment of the single-strut cantilever beam, E is the elastic modulus of the single-strut flexible wall nozzle, b is the width of the single-strut flexible wall nozzle, and h is the thickness of the single-strut flexible wall nozzle.

[0071] The bending moment of the cantilever beam can be expressed as

[0072] M = P (x1-x) cos θ + P (y1-y) sin θ (2)

[0073] Wherein, P is the force of the right end point of the cantilever beam, which is expressed by a positive value, x1 and y1 are the horizontal coordinate and vertical coordinate of the right end point of the cantilever beam after deformation in the Cartesian coordinate system, and θ is the angle of rotation of the strut. (x, y) is the coordinates of any point on the cantilever beam in the Cartesian coordinate system.

[0074] The relationship between the Cartesian coordinates and the curvilinear coordinates is

[0075]

[0076] Substitute (2) into (1) and consider (3), the differential equation can be obtained

[0077]

[0078] Integrate both sides of the equation twice and bring in the boundary conditions of the two end points of the cantilever beam to obtain

[0079]

[0080] Wherein, α L is the inclination angle of the right end point of the cantilever beam after deformation

[0081] (5) is transformed into the form of elliptic integral

[0082]

[0083] where,

[0084]

[0085] F is the first kind of incomplete elliptic integral. According to (3), the coordinates of any point on the cantilever beam can be obtained

[0086]

[0087] where,

[0088]

[0089] E is the second kind of incomplete elliptic integral. Since the strut rotates around the fixed point in the process of deformation, the coordinates of the coupling point of the cantilever beam and the strut can be expressed by geometric method.

[0090]

[0091] where, L is the total length of the single support flexible wall nozzle, S0 is the initial length of the strut, and ΔS is the elongation of the strut.

[0092] Combining (7) and (8) with the coordinates of the right end point of the cantilever beam after deformation, the following equation group can be obtained

[0093]

[0094] where, l is the length of the single support flexible wall nozzle, F(k, γ) represents the first kind of incomplete elliptic integral, E(k, γ) represents the second kind of incomplete elliptic integral, f is the first incomplete elliptic integral on the profile curve with the interval [γ0, γ s ] on the profile curve, e is the second incomplete elliptic integral on the profile curve with the interval [γ0, γ s ], S0 is the initial value of the strut length, ΔS is the elongation of the strut, θ is the rotation angle of the strut, P is the force of the strut on the cantilever beam, α L is the inclination angle of the right end point of the cantilever beam, k is the modulus of the elliptic integral, γ is the upper limit of the integral, and θ is the rotation angle of the strut.

[0095] Substitute all the obtained known parameters into the equation group, and the equation group only contains three unknown quantities, which are P, α L and θ, P is the force of the strut on the cantilever beam, α L is the inclination angle of the right end point of the cantilever beam, and θ is the rotation angle of the strut.

[0096] In the present example, according to the derivation process of the above formula, a program for calculating the profile curve is written on the MAPLE software. The known parameters are obtained, including the length L of the single-support flexible wall nozzle of 200 mm, the width b of the single-support flexible wall nozzle of 20 mm, the thickness h of the single-support flexible wall nozzle of 1 mm, the elastic modulus E of the single-support flexible wall nozzle of 2.5 GPa, the initial value S0 of the strut length of 100 mm, and the elongation ΔS of the strut of 220 mm. The MAPLE calculation profile curve program is calculated by substituting the values into the MAPLE software, and the force P of the strut on the cantilever beam is 0.0819 N, the inclination angle a of the right end point of the single-strut cantilever beam is 0.057, and the angle θ of the strut rotation is 0.3786. Then, the coordinate values of the upper point of the profile curve in the rectangular coordinate system are calculated through the three parameters. L The inclination angle a of the right end point of the single-strut cantilever beam is 0.057, and the angle θ of the strut rotation is 0.3786. Then, the coordinate values of the upper point of the profile curve in the rectangular coordinate system are calculated through the three parameters.

[0097] Step 105, the target profile curve is obtained by subtracting the profile curve from the target profile curve. The target profile curve is calculated according to the design output Mach number through aerodynamic theory. The computational fluid dynamics software can be ANSYS FLUENT, CFX, PHOENICS, STAR-CCM, OpenFOAM or COMSOL, which can calculate the target profile curve. Specifically, the longitudinal and transverse coordinate values of each point on the profile curve in the rectangular coordinate system are calculated. The values of the three parameters, the angle θ of the strut rotation, the force P of the strut on the cantilever beam, and the inclination angle a of the right end point of the single-strut cantilever beam, are calculated by the mathematical software MAPLE software. The coordinate values of the points of the profile curve in the rectangular coordinate system are calculated by substituting the three parameter values into the mathematical software MAPLE software. The coordinate values of the points of the target profile curve and the calculated profile curve are subtracted to obtain the profile curve deviation. L The inclination angle a of the right end point of the single-strut cantilever beam is 0.057, and the angle θ of the strut rotation is 0.3786. Then, the coordinate values of the upper point of the profile curve in the rectangular coordinate system are calculated through the three parameters.

[0098] When the profile curve deviation is greater than the maximum profile curve deviation, the values of the strut parameters are adjusted according to the profile curve deviation, and the MAPLE software is repeatedly used for iterative calculation until the profile curve deviation between the profile curve and the target profile curve is less than the maximum profile curve deviation, and the single-support flexible wall nozzle profile curve is obtained. The maximum profile curve deviation refers to the maximum value ε of the difference between the calculated profile curve and the target profile curve, and the value range is 0.1-0.5 mm. In the present example, the specific process is as follows.

[0099] The maximum profile curve deviation refers to the maximum value ε of the difference between the calculated profile curve and the target profile curve,

[0100] The maximum profile curve deviation is ε, and the value range of ε is set to 0.1-0.5 mm,

[0101] y i and respectively represent the longitudinal coordinate values of the calculated profile curve and the target profile curve, the profile curve deviation is the coordinate value difference, if

[0102]

[0103] The reduced strut elongation is

[0104]

[0105] If

[0106]

[0107] The increased strut elongation is

[0108]

[0109] The strut adjustment parameter value is substituted into the MAPLE software again for iterative calculation, the above strut parameter value adjustment and MAPLE software iterative calculation are repeatedly performed until the profile curve deviation is less than the maximum profile curve deviation, at which time the single-support-point flexible-wall nozzle profile curve is obtained.

[0110] In step 105, the profile curve deviation can also be represented as a root mean square deviation R. Then, the process of adjusting the strut parameter value according to the profile curve root mean square deviation is:

[0111] The maximum profile curve deviation refers to the maximum value of the difference between the calculated profile curve and the target profile curve,

[0112] The maximum profile curve deviation is ε, and the value range of ε is set to 0.1-0.5mm,

[0113] y i and respectively represent the longitudinal coordinate values of the calculated profile curve and the target profile curve, N is the number of data points, the profile curve deviation is the root mean square deviation R, and then

[0114]

[0115] If R>ε

[0116] The strut elongation is adjusted, that is, the strut adjustment parameter is substituted into the MAPLE software again for iterative calculation. It is assumed that the R value becomes larger after the strut elongation is adjusted, so the strut elongation needs to be reduced, and the MAPLE software iterative calculation is repeatedly performed. Conversely, if the R value becomes larger after the strut is shortened, the strut elongation needs to be adjusted, and the MAPLE software iterative calculation is performed until R<ε is satisfied, at which time the profile curve is obtained.

[0117] It should be noted that, in the description of the embodiments of the present application, the terms "first", "second", etc. are used only to distinguish between different objects, and cannot be understood as indicating or implying relative importance or chronological order. In addition, in the description of the present application, unless otherwise stated, the meaning of "a plurality of" is at least two.

[0118] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0119] The present application is described with reference to flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as a combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 means for performing the functions specified in the flowchart and / or block diagram.

[0120] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a product including instruction means, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 means for performing the functions specified in the flowchart and / or block diagram.

[0121] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a process for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 means for performing the functions specified in the flowchart and / or block diagram.

[0122] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method of designing a profile curve of a single pivot flexible wall nozzle, characterized in that, The application relates to a method for obtaining a single-point flexible-wall nozzle curve. The method comprises the following steps: obtaining design parameters of a single-point flexible-wall nozzle; determining initial values of support rod parameters according to the design parameters; obtaining a target profile curve; compiling a profile curve calculation program by using MAPLE software, inputting the design parameters of the single-point flexible-wall nozzle and the initial values of the support rod parameters into the profile curve calculation program, and calculating the profile curve; obtaining a profile curve deviation by subtracting the target profile curve from the profile curve; when the profile curve deviation is greater than a maximum profile curve deviation, adjusting the numerical values of the support rod parameters according to the profile curve deviation, and repeatedly performing iterative calculation by using the MAPLE software until the profile curve deviation between the profile curve and the target profile curve is less than the maximum profile curve deviation, and the profile curve of the single-point flexible-wall nozzle is obtained. The method comprises the following steps: simplifying the single-point flexible-wall nozzle into a single-rod cantilever beam, obtaining a balance equation of the single-rod cantilever beam in a curve coordinate system according to the Euler-Bernoulli beam large deformation theory, obtaining a profile curve expression by the balance equation, obtaining a profile curve equation group formula expression form by a first incomplete elliptic integral and a second incomplete elliptic integral, and inputting the design parameters of the single-point flexible-wall nozzle and the initial values of the support rod parameters into the profile curve equation group to obtain the profile curve. The method comprises the following steps: obtaining the width of the single-point flexible-wall nozzle; obtaining the length of the single-point flexible-wall nozzle; obtaining the thickness of the single-point flexible-wall nozzle; and obtaining the elastic modulus of the single-point flexible-wall nozzle. The support rod parameters comprise a support rod length and a support rod elongation. When the profile curve deviation is greater than the maximum profile curve deviation, the numerical values of the support rod parameters are adjusted according to the profile curve deviation, iterative calculation is repeatedly performed by using the MAPLE software until the profile curve deviation between the profile curve and the target profile curve is less than the maximum profile curve deviation, and the profile curve of the single-point flexible-wall nozzle is obtained. The maximum profile curve deviation refers to the maximum value of the difference between the calculated profile curve and the target profile curve. The maximum profile curve deviation is epsilon, the value range of epsilon is 0.1-0.5 mm, the difference is delta, if delta is greater than epsilon, the support rod elongation is reduced by delta-epsilon, if delta is less than epsilon, the support rod elongation is increased by epsilon-delta, the numerical values of the support rod adjustment parameters are input into the MAPLE software for iterative calculation again, the above comparison process is repeated, the support rod parameter adjustment and the MAPLE software iterative calculation are repeatedly performed until the profile curve deviation is less than the maximum profile curve deviation, and the profile curve of the single-point flexible-wall nozzle is obtained. The maximum profile curve deviation refers to the maximum value of the difference between the calculated profile curve and the target profile curve. wherein: α is the angle of inclination of a single-braced cantilever beam, s is the curve coordinate of a profile curve, M is the bending moment of a single-braced cantilever beam, E is the modulus of elasticity of a single-braced flexible wall nozzle, b is the width of a single-braced flexible wall nozzle, h is the thickness of a single-braced flexible wall nozzle; ​ wherein: l L is the length of the single-brace cantilever beam, F( k , ​ ) represents the first incomplete elliptic integral, represents the second incomplete elliptic integral; f is the first incomplete elliptic integral of the interval [0, ​ , ​ s ] on the profile curve, e is the second incomplete elliptic integral of the interval [0, ​ , ​ s ] on the profile curve, S 0 is the initial value of the length of the brace, Δ S is the length of the brace, ​ is the angle of rotation of the brace, P is the force value at the intersection of the brace and the cantilever beam, α L is the inclination angle of the right end point of the single-brace cantilever beam, k is the modulus of the elliptic integral, ​ is the upper limit of integration; ​ 2. The method of claim 1, wherein, ​ ​ ​ ​ ​ 3. The method of claim 1, wherein, ​ 4. The method of claim 1, wherein, ​ ​ ​ and respectively represent the ordinate values of the calculated profile curve and the target profile curve, the profile curve deviation being the difference between the ordinate values ​ ​ . ​ ​ . ​ 5. The method of claim 1, wherein, ​ ​ The maximum deviation of the profile curve is ε, and the value range of ε is set as 0.1-0.5 mm, and denote the ordinate values of the calculated profile curve and the target profile curve, respectively, N is the number of data points, and the profile curve deviation is the root mean square deviation R then If Then the length of the adjusting support rod is adjusted, i.e. the adjusting parameter of the support rod is substituted into the MAPLE software again for iterative calculation, and the adjusting parameter of the support rod is adjusted again Adjusting the length of the strut R If the value becomes larger, the length of the strut needs to be reduced, and the MAPLE software iterative calculation is repeated; conversely, if the length of the strut is reduced R If the value becomes larger, the length of the strut needs to be adjusted, the MAPLE software iterative calculation is repeated, until , at this time, the single support flexible wall nozzle profile curve is obtained.

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