Guide vane structure optimization method, guide vane structure optimization system and guide vane structure

Abstract

The present invention discloses a guide vane structure optimization method, a guide vane structure optimization system and a guide vane structure. The structure optimization method establishes a parameterized numerical model of the guide vane structure based on a multi-physical field coupling mechanism, that is, an equivalent stress calculation model of the guide vane structure is established based on the coupling relationship between physical fields. The equivalent stress is calculated by nonlinear coupling of the fluid stress and the centrifugal stress suffered by the guide vane structure, and a quantitative correlation between the key parameters of the guide vane structure and the stress response is established. According to the guide vane structure parameters that affect the stress suffered by the guide vane structure, an explicit relationship between the guide vane structure parameters and the equivalent stress is established, and a multi-objective constraint optimization equation is constructed. Based on the equivalent stress calculation model and the explicit relationship between the guide vane structure parameters and the equivalent stress, a structural optimization equation of the guide vane structure is constructed, and sequential quadratic programming iterative optimization is implemented. Based on the structural optimization equation of the guide vane structure, an SQP algorithm is used to perform iterative calculation until the convergence condition is met to obtain the optimized value of the guide vane structure parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid mechanical engineering, and in particular to a guide vane structure optimization method, a guide vane structure optimization system, and a guide vane structure. Background Art

[0002] The guide vane of the pump is a key component in centrifugal pumps and mixed flow pumps, mainly used to guide fluid flow and realize energy conversion.

[0003] In the design of pump guide vane structures, traditional guide vane design methods mostly rely on empirical formulas or single physical field analysis, and do not fully consider the coupling effect of fluid dynamics and centrifugal force, resulting in inaccurate stress prediction. At the same time, traditional guide vane design methods lack explicit correlation models for the optimization of guide vane design parameters, making it difficult to quickly determine the optimal solution. The design cycle is long and local overstress problems are prone to occur. Summary of the Invention

[0004] In order to solve the technical problems raised in the above background technology, the purpose of the present invention is to provide a guide vane structure optimization method, a guide vane structure optimization system and a guide vane structure, so as to address the problems of complex multi-physical field coupling analysis and low optimization efficiency in the guide vane design process of traditional pumps, and propose a high-precision and rapid optimization design method for the guide vane structure.

[0005] In order to achieve the above-mentioned object, the present invention provides a guide vane structure optimization method. In the technical solution of the present invention, the guide vane structure optimization method specifically includes the following steps:

[0006] Step S1: Establishing a parameterized numerical model of the guide vane structure based on a multi-physics field coupling mechanism: Establishing an equivalent stress calculation model for the guide vane structure based on the coupling relationship between physical fields. The equivalent stress is calculated by nonlinearly coupling the fluid stress and centrifugal stress on the guide vane structure.

[0007] Step S2: Establishing a quantitative correlation between the key parameters of the guide vane structure and the stress response: Based on the guide vane structural parameters that affect the stress on the guide vane structure, establish an explicit relationship between the guide vane structural parameters and the equivalent stress;

[0008] Step S3: Constructing a multi-objective constraint optimization equation: Based on the equivalent stress calculation model and the explicit relationship between the guide vane structural parameters and the equivalent stress, constructing a structural optimization equation for the guide vane structure;

[0009] Step S4: Implement sequential quadratic programming iterative optimization: Based on the structural optimization equation of the guide vane structure, use the SQP algorithm to perform iterative calculations until the convergence conditions are met to obtain the optimized values ​​of the guide vane structural parameters.

[0010] Furthermore, in step S1, the equivalent stress is calculated by nonlinear coupling of the fluid stress and the centrifugal stress on the guide vane structure, which is specifically expressed as:

[0011] Constructing equivalent stress through nonlinear superposition principle : ;

[0012] in, Expressed as the equivalent stress of the guide vane structure, Expressed as the fluid stress of the guide vane structure, Expressed as the centrifugal stress of the guide vane structure, 、 、 Expressed as weight coefficient, Expressed as the yield strength of the guide vane structural material.

[0013] Furthermore, in the step S2, according to the guide vane structure parameters that affect the stress on the guide vane structure, specifically including:

[0014] Number of blades , inlet angle , blade thickness , blade angle and diffusion angle ;

[0015] Among them, the guide vane structural parameters and equivalent stress are established The explicit relationship, that is, the parameter mapping relationship, is specifically expressed as:

[0016] .

[0017] Furthermore, in step S3, a structural optimization equation of the guide vane structure is constructed, specifically including:

[0018] Equivalent stress Minimization is the objective function, and a multivariable optimization equation including the guide vane structural parameters is established, which is specifically expressed as:

[0019] ;

[0020] The geometric constraints and performance constraints of the guide vane structure are defined as boundary conditions of the optimization equation.

[0021] Furthermore, in step S4, the convergence condition is represented by an equivalent stress change rate being less than 1%.

[0022] Furthermore, in the technical solution of the present invention, the fluid stress It is composed of impact stress term and pressure load term to quantify the mechanical effect of fluid on the guide vane structure. Specifically expressed as:

[0023] ;

[0024] in, 、 Expressed as an empirical coefficient, Expressed as the fluid density, Expressed as flow rate, Expressed as the single flow channel area, Expressed as the flow channel pressure difference, Expressed as guide vane length.

[0025] Furthermore, in the technical solution of the present invention, centrifugal stress Used to quantify the tensile effect of the rotating inertia force on the blade, centrifugal stress Specifically expressed as:

[0026] ;

[0027] in, Expressed as the density of the guide vane structure material, Expressed as angular velocity, Expressed as the guide vane diameter.

[0028] The technical solution of the present invention further includes a guide vane structure optimization system for implementing the guide vane structure optimization method described above. The guide vane structure optimization system includes:

[0029] Parameter input module: used to receive guide vane structural parameters and operating condition parameters;

[0030] Stress calculation module: performs equivalent stress calculation based on the equivalent stress calculation model;

[0031] Optimization algorithm module: According to the structural optimization equation, the optimized values ​​of the guide vane structural parameters are calculated based on the SQP algorithm;

[0032] Structural output module: outputs the optimization results of the guide vane structure.

[0033] Another aspect of the present invention further provides a guide vane structure, which is optimized according to the guide vane structure optimization system described above.

[0034] Beneficial effects: In summary, the present invention provides a guide vane structure optimization method, a guide vane structure optimization system and a guide vane structure. In the technical solution of the present invention, a nonlinear coupling model of fluid stress and centrifugal stress is established, and based on the guide vane structure parameters that affect the stress of the guide vane structure, an explicit functional relationship between the guide vane structure parameters and the equivalent stress is established. At the same time, the SQP algorithm is combined for iterative calculation to achieve efficient optimization of the guide vane parameters. Specifically, the present invention aims at the problems of complex multi-physical field coupling analysis and low optimization efficiency in the guide vane design process of traditional pumps, and provides a high-precision and rapid optimization design method for the guide vane structure, which can significantly improve the stress prediction accuracy and shorten the design and optimization cycle of the guide vane structure.

[0035] Other features and advantages of the present invention will be set forth in the description that follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] Figure 1 is a flow chart of a guide vane structure optimization method according to an embodiment of the present invention;

[0038] Figure 2 is a schematic diagram of a guide vane structure optimization system according to an embodiment of the present invention;

[0039] Figure 3 Schematic diagram of structural optimization of a guide vane structure according to an embodiment of the present invention, wherein (a) is a top view of the guide vane structure before and after optimization, and (b) is a bottom view of the guide vane structure before and after optimization. DETAILED DESCRIPTION

[0040] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] The core of the embodiments of the present invention is to provide a guide vane structure optimization method, a guide vane structure optimization system and a guide vane structure. In response to the problems of complex multi-physical field coupling analysis and low optimization efficiency in the guide vane design process of traditional pumps, a high-precision and rapid optimization design method for the guide vane structure is proposed.

[0042] In one aspect, an embodiment of the present invention provides a guide vane structure optimization method. Figure 1 FIG. 1 is a flow chart of a guide vane structure optimization method according to an embodiment of the present invention. Figure 1 As shown, in this embodiment, the guide vane structure optimization method specifically includes the following steps:

[0043] Step S1: Establishing a parameterized numerical model of the guide vane structure based on a multi-physics field coupling mechanism: Establishing an equivalent stress calculation model for the guide vane structure based on the coupling relationship between physical fields. The equivalent stress is calculated by nonlinearly coupling the fluid stress and centrifugal stress on the guide vane structure.

[0044] Step S2: Establishing a quantitative correlation between the key parameters of the guide vane structure and the stress response: Based on the guide vane structural parameters that affect the stress on the guide vane structure, establish an explicit relationship between the guide vane structural parameters and the equivalent stress;

[0045] Step S3: Constructing a multi-objective constraint optimization equation: Based on the equivalent stress calculation model and the explicit relationship between the guide vane structural parameters and the equivalent stress, constructing a structural optimization equation for the guide vane structure;

[0046] Step S4: Implement sequential quadratic programming iterative optimization: Based on the structural optimization equation of the guide vane structure, use the SQP algorithm to perform iterative calculations until the convergence conditions are met to obtain the optimized values ​​of the guide vane structural parameters.

[0047] Specifically, in step S1, the equivalent stress is calculated by nonlinear coupling of the fluid stress and the centrifugal stress on the guide vane structure, which can be expressed as follows:

[0048] Constructing equivalent stress through nonlinear superposition principle : ;

[0049] in, Expressed as the equivalent stress of the guide vane structure, Expressed as the fluid stress of the guide vane structure, Expressed as the centrifugal stress of the guide vane structure, 、 、 Expressed as weight coefficient, Expressed as the yield strength of the guide vane structural material, It is a linear term. According to the different weights of the influence of fluid stress and centrifugal stress on the guide vane structure, it is directly weighted and summed. The nonlinear term Reflecting the dual stress coupling effect, the yield strength is introduced Normalization is performed, and after normalization, the influence of high stress areas is further amplified by squaring to improve the model accuracy of nonlinear terms.

[0050] Specifically, in step S2, according to the guide vane structure parameters that affect the stress on the guide vane structure, specifically including:

[0051] Number of blades , inlet angle , blade thickness , blade angle and diffusion angle ;

[0052] Among them, the guide vane structural parameters and equivalent stress are established The explicit relationship, that is, the parameter mapping relationship, is specifically expressed as:

[0053] ;

[0054] Guide vane structural parameters ( 、 、 、 and ) Stress on the guide vane structure The impact is shown in the following table:

[0055]

[0056] Specifically, in step S3, a structural optimization equation of the guide vane structure is constructed, which specifically includes:

[0057] Equivalent stress Minimization is the objective function, and a multivariable optimization equation including the guide vane structural parameters is established, which is specifically expressed as:

[0058] ;

[0059] Define the geometric constraints and performance constraints of the guide vane structure as boundary conditions of the optimization equation:

[0060] Geometric constraints: , , ;

[0061] The performance constraints are determined based on the head and efficiency coefficient of the pump installed with the guide vane structure;

[0062] The optimized values ​​of the guide vane structural parameters are obtained through integral solution.

[0063] Specifically, in step S4, the convergence condition is expressed as the equivalent stress change rate being less than 1%.

[0064] In this embodiment, the fluid stress It is composed of impact stress term and pressure load term to quantify the mechanical effect of fluid on the guide vane structure. Specifically expressed as:

[0065] , ;

[0066] in, 、 Expressed as an empirical coefficient, Expressed as the fluid density, Expressed as flow rate, Expressed as the single flow channel area, Expressed as the flow channel pressure difference, Expressed as the guide vane length, Expressed as the guide vane diameter, the impact stress term Converted from fluid kinetic energy, it is proportional to the square of the flow velocity ( ), it can be further concluded that the flow rate and the number of blades , single flow channel area and inlet angle Inversely proportional, increasing these parameters can reduce the impact stress; the pressure load term By flow channel pressure difference and blade aspect ratio ( ) is determined by the pressure load term, which reflects the bending stress of the guide vane structure. It can be further concluded that the aspect ratio ( ) is larger, the more significant the blade bending stress is, and the blade thickness should be reduced. This will increase the pressure load term pressure.

[0067] In this embodiment, the centrifugal stress Used to quantify the tensile effect of the rotating inertia force on the blade to avoid material overload and centrifugal stress Specifically expressed as:

[0068] ;

[0069] in, Expressed as the density of the guide vane structure material, Expressed as angular velocity, Expressed as the guide vane diameter, It is expressed as a simplified integral model of centrifugal force. The blade is approximately a rectangular plate of equal thickness. The centrifugal force is integrated along the radius. The integral result is , blade volume and blade thickness , blade angle And it is proportional to the square of the radius. The larger the volume, the higher the centrifugal stress. At the same time, the centrifugal stress is proportional to the density of the guide vane structure material. , the square of the speed proportional to; This reflects the mutual support effect of multiple blades. Increasing the number of blades will weaken the support effect and cause a slight increase in centrifugal stress.

[0070] For example, for each of the above steps, this embodiment provides a specific application scenario:

[0071] The following is a centrifugal pump according to this embodiment ( =10 5 Initial design parameters of the guide vane structure (Pa):

[0072]

[0073] Among them, the value of the weight coefficient is: 、 、 ;

[0074] The value of the empirical coefficient is: , ;

[0075] First iteration calculation (initial parameters):

[0076] Calculating fluid stress :

[0077] ;

[0078] Calculation of centrifugal stress :

[0079] ;

[0080] Calculate equivalent stress :

[0081] ;

[0082] Calculate the partial derivatives of the structural optimization equation with respect to each guide vane structural parameter:

[0083] Number of blades Partial derivatives of :

[0084] ;

[0085] Fluid stress versus blade number Partial derivatives of :

[0086] ;

[0087] Centrifugal stress versus blade number Partial derivatives of :

[0088] ;

[0089] get:

[0090] ;

[0091] Right now When, increase The value of equivalent stress The number of leaves is calculated based on the gradient descent method. Parameter optimization, due to the calculated The value is small, and the optimization uses small gradient changes: , rounded to ;

[0092] The second iteration calculation ( ):

[0093] Calculating fluid stress :

[0094] The process is the same as above, and the calculation is ;

[0095] Calculation of centrifugal stress :

[0096] The process is the same as above, and the calculation is ;

[0097] Calculate equivalent stress :

[0098] The process is the same as above, and the calculation is ;

[0099] That is, the equivalent stress decreases by about 0.14%<1% compared with the initial value, converges, and no further optimization is required. The optimized value is It should be noted that, due to and Calculate equivalent stress The gap is smaller, so The convergence condition may have been met when Further verification, similarly, the number of leaves Equivalent stress The impact is small.

[0100] Replace the guide vane structural parameters and calculate the structural optimization equation for blade thickness The partial derivative of the blade thickness is obtained by the same calculation process as above. Partial derivatives of :

[0101] ;

[0102] Centrifugal stress on blade thickness Partial derivatives of :

[0103] ;

[0104] get:

[0105]

[0106] Since the unit leaf thickness (1m) is much larger than the actual value (0.01m), so the calculated result is larger. It is a negative value, which means it increases The value of equivalent stress For a downward trend, the optimization adopts a large gradient change: ;

[0107] The third iteration calculation ( ):

[0108] Calculating fluid stress :

[0109] The process is the same as above, and the calculation is ;

[0110] Calculation of centrifugal stress :

[0111] The process is the same as above, and the calculation is ;

[0112] Calculate equivalent stress :

[0113] The process is the same as above, and the calculation is ;

[0114] That is, the equivalent stress decreases by about 44.65% compared with the initial value, which is greater than 1%. This means that the solution has not converged and needs to be optimized further. The optimization process is the same as above.

[0115] The process is the same as above, and the blade thickness is further iterated and calculated The convergence value of the guide vane structure parameters is then changed to calculate the structural optimization equation for the inlet angle , blade angle and diffusion angle The partial derivatives of are calculated in the same way as above until the guide vane structural parameters converge and the optimized values ​​of the guide vane structural parameters are obtained.

[0116] Among them, the geometric constraints and performance constraints of the guide vane structure are the boundary conditions of the optimization equation, that is, the optimized values ​​of the guide vane structure parameters need to meet the boundary conditions.

[0117] In this embodiment, a guide vane structure optimization system is also included for implementing the guide vane structure optimization method described above. Figure 2 FIG. 1 is a schematic diagram of a guide vane structure optimization system according to an embodiment of the present invention. Figure 2As shown, the guide vane structure optimization system includes:

[0118] Parameter input module: used to receive guide vane structural parameters and operating condition parameters;

[0119] Stress calculation module: performs equivalent stress calculation based on the equivalent stress calculation model;

[0120] Optimization algorithm module: According to the structural optimization equation, the optimized values ​​of the guide vane structural parameters are calculated based on the SQP algorithm;

[0121] Structural output module: outputs the optimization results of the guide vane structure.

[0122] Specifically, this embodiment also provides a guide vane structure. Figure 3 FIG. 1 is a schematic diagram of structural optimization of a guide vane structure according to an embodiment of the present invention. Figure 3 As shown, the guide vane structure is optimized according to a guide vane structure optimization system described above, wherein (a) is a top view of the structure before and after the optimization of the guide vane structure, and (b) is a bottom view of the structure before and after the optimization of the guide vane structure.

[0123] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A guide vane structure optimization method, characterized in that: The steps include: Step S1: Establish a parameterized numerical model of the guide vane structure based on the multi-physics field coupling mechanism: Establish an equivalent stress calculation model of the guide vane structure based on the coupling relationship between physical fields. The equivalent stress is calculated by the fluid stress and centrifugal stress on the guide vane structure through nonlinear coupling, which is specifically expressed as: Constructing equivalent stress through nonlinear superposition principle : ; in, Expressed as the equivalent stress of the guide vane structure, Expressed as the fluid stress of the guide vane structure, Expressed as the centrifugal stress of the guide vane structure, 、 、 Expressed as weight coefficient, Expressed as the yield strength of the guide vane structural material, It is a linear term. According to the different weights of the influence of fluid stress and centrifugal stress on the guide vane structure, it is directly weighted and summed. The nonlinear term Reflecting the dual stress coupling effect, the yield strength is introduced Normalization is performed, and after normalization, the influence of high stress areas is further amplified by squaring to improve the model accuracy of nonlinear terms; Step S2: Establishing a quantitative correlation between the key parameters of the guide vane structure and the stress response: Based on the guide vane structural parameters that affect the stress on the guide vane structure, establish an explicit relationship between the guide vane structural parameters and the equivalent stress; Step S3: Constructing a multi-objective constraint optimization equation: Based on the equivalent stress calculation model and the explicit relationship between the guide vane structural parameters and the equivalent stress, constructing a structural optimization equation for the guide vane structure; Step S4: Implement sequential quadratic programming iterative optimization: Based on the structural optimization equation of the guide vane structure, use the SQP algorithm to perform iterative calculations until the convergence conditions are met to obtain the optimized values ​​of the guide vane structural parameters.

2. A guide vane structure optimization method according to claim 1, characterized in that: In the step S2, according to the guide vane structure parameters that affect the stress on the guide vane structure, specifically including: Number of blades , inlet angle , blade thickness , blade angle and diffusion angle ; Among them, the guide vane structural parameters and equivalent stress are established The explicit relationship, that is, the parameter mapping relationship, is specifically expressed as: 。 3. A guide vane structure optimization method according to claim 2, characterized in that: In step S3, a structural optimization equation of the guide vane structure is constructed, specifically including: Equivalent stress Minimization is the objective function, and a multivariable optimization equation including the guide vane structural parameters is established, which is specifically expressed as: ； The geometric constraints and performance constraints of the guide vane structure are defined as boundary conditions of the optimization equation.

4. The guide vane structure optimization method according to claim 1, characterized in that: In step S4, the convergence condition is represented by an equivalent stress change rate being less than 1%.

5. The guide vane structure optimization method according to claim 2, characterized in that: Fluid stress It consists of impact stress term and pressure load term to quantify the mechanical effect of fluid on the guide vane structure. Specifically expressed as: ； in, 、 Expressed as an empirical coefficient, Expressed as the fluid density, Expressed as flow rate, Expressed as the single flow channel area, Expressed as the flow channel pressure difference, Expressed as guide vane length.

6. A guide vane structure optimization method according to claim 2, characterized in that: centrifugal stress Used to quantify the tensile effect of the rotating inertia force on the blade, centrifugal stress Specifically expressed as: ； in, Expressed as the density of the guide vane structure material, Expressed as angular velocity, Expressed as the guide vane diameter.

7. A guide vane structure optimization system, used to implement a guide vane structure optimization method according to any one of claims 1 to 6, characterized in that: include: Parameter input module: used to receive guide vane structural parameters and operating condition parameters; Stress calculation module: performs equivalent stress calculation based on the equivalent stress calculation model; Optimization algorithm module: According to the structural optimization equation, the optimized values ​​of the guide vane structural parameters are calculated based on the SQP algorithm; Structural output module: outputs the optimization results of the guide vane structure.

8. A guide vane structure, characterized in that: A guide vane structure optimization system according to claim 7 is optimized and implemented.

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