A method for reinforcing a fan impeller back plate

Abstract

The application belongs to the technical field of ventilators, and particularly relates to a reinforcing method for a rear disc of a ventilator impeller; the method comprises the following steps: step one, strength analysis of the ventilator impeller is performed through finite element analysis, and a finite element simulation model is established; step two, topological optimization is performed on the ventilator impeller model that fails to pass simulation checking, material distribution of the structure is determined through topological optimization analysis of the ventilator impeller structure; step three, a rear disc patch is designed according to the topological optimization result, the rear disc patch is used to reinforce the rear disc of the impeller, and the optimized impeller structure is rechecked through simulation until the checking is passed; compared with the prior art, the application has the advantages and positive effects that the positions of the rear disc of the impeller that need to be reinforced due to large stress and weak strength can be intuitively found out, the weak positions of the rear disc of the impeller are locally reinforced, and the weight of the ventilator impeller is reduced.

Description

Technical Field

[0001] This invention belongs to the field of ventilation fan technology, specifically relating to a method for reinforcing the rear disc of a ventilation fan impeller. Background Technology

[0002] During the design of a wind turbine structure, the strength of the impeller must be checked. Traditional checking methods can only check the impeller cover, blades, and rear disc as a whole, which cannot intuitively determine the strength or stress of each component. As a result, when the strength of the rear disc is insufficient, the entire rear disc usually needs to be thickened. Since the rear disc is the part on the impeller that connects the front disc and blades and transmits torque, its thickness is inherently greater than that of the front disc and blades, and it accounts for a large proportion of the impeller's weight. Thickening the rear disc as a whole leads to a significant increase in the overall weight of the impeller, which in turn leads to a large starting torque of the impeller. On the one hand, this results in a longer start-up time for the wind turbine, causing severe motor overheating during start-up; on the other hand, it increases the stress on the main shaft and the load on the bearings, leading to increased costs.

[0003] In addition, the increased weight of the impeller back plate leads to a decrease in safety and stability. Therefore, there is an urgent need for a method to reinforce the impeller back plate of a fan with low weight and high stability. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for reinforcing the rear disc of a ventilation fan impeller.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for reinforcing the rear disc of a ventilator impeller, wherein the ventilator impeller to be reinforced includes an impeller rear disc and a shaft disc, the impeller rear disc and the shaft disc being detachably connected, and the ventilator impeller to be reinforced also includes a rear disc patch, the rear disc patch being welded to the impeller rear disc, and the method for reinforcing the rear disc of the ventilator impeller includes the following steps:

[0006] Step 1: Perform strength analysis on the fan impeller using finite element analysis to verify whether the material strength meets the structural requirements. Based on the stress conditions of the fan impeller, establish a finite element simulation model.

[0007] Step 2: Perform topology optimization on the fan impeller model that fails the simulation verification. By performing topology optimization analysis on the fan impeller structure, determine the material distribution of the structure.

[0008] Step 3: Design the rear disk patch based on the topology optimization results. Combine the stress distribution in the simulation results and the material distribution of the impeller rear disk in the topology optimization, and reinforce the impeller rear disk with the rear disk patch. The optimized impeller structure is then re-simulated and verified until it passes the verification.

[0009] Preferably, step one includes: structural design of the fan impeller to obtain a three-dimensional model of the fan impeller; obtaining the material parameters and operating condition parameters of the designed fan impeller; using finite element analysis software, importing the material parameters and operating condition parameters of the fan impeller into the finite element analysis software to establish a finite element simulation model; calculating the structural strength of the fan impeller based on the finite element simulation model, and setting boundary conditions according to the rotational conditions of the fan impeller; analyzing the overall stress on the fan impeller and selecting the impeller back plate for analysis.

[0010] Preferably, the material parameters and operating condition parameters of the fan impeller include the density, elastic modulus, Poisson's ratio, rotational speed, and gravitational acceleration of the fan impeller material.

[0011] As a preferred method, the stress on the fan impeller under centrifugal force and gravity load is calculated, and this value is compared with the yield strength of the fan impeller material.

[0012] Preferably, the shaft disk and the impeller rear disk are connected by bolts. In the finite element simulation model, the bolt connection between the shaft disk and the impeller rear disk is simplified to two-sided bonding, that is, using a tie for binding connection.

[0013] Preferably, step two includes the following steps: obtaining the optimized fan impeller material parameters and operating condition parameters; using finite element optimization software, importing the fan impeller material parameters and operating condition parameters into the finite element optimization software to establish a topology optimization model; seeking the material distribution based on the topology optimization model, and setting boundary conditions based on the fan impeller rotation conditions; defining the design variables for topology optimization, setting the optimization response for topology optimization, setting the optimization constraints for topology optimization, setting the optimization objective for topology optimization, and redesigning the structure based on the topology optimization results.

[0014] Preferably, the design variables for topology optimization include defining minimum size constraints, maximum size constraints, and symmetry constraints;

[0015] The optimized response of the topology optimization includes defining the volume fraction response, compliance response, and stress response;

[0016] The optimization constraints for the topology optimization include defining minimum size constraints, maximum size constraints, and symmetry constraints.

[0017] The optimization objectives of the topology optimization include minimum compliance corresponding to maximum stiffness, and defining the impeller structure as having minimum compliance.

[0018] As a preferred option, the material parameters and operating condition parameters of the optimized fan impeller are obtained, including the density, elastic modulus, Poisson's ratio and rotational speed of the fan impeller material, and the material properties of the design domain and non-design domain are set.

[0019] As a preferred method, the stress on the fan impeller under centrifugal load is calculated, and the material distribution is determined based on the stress.

[0020] As a preferred option, step three includes attaching a back plate patch to the impeller back plate. The diameter of the back plate patch is determined according to the material distribution of topology optimization. The back plate patch is attached to and welded to the impeller back plate. The back plate patch and the impeller back plate have the same size inner hole, and the inner hole of the back plate patch and the inner hole of the impeller back plate are located on the same axis. Then, the optimized structure is simulated and verified to obtain a fan impeller with sufficient strength.

[0021] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0022] (1) Strength analysis of the fan impeller by finite element analysis can intuitively reflect the stress of the fan impeller. Topology optimization of the fan impeller model that fails the simulation verification can intuitively identify the parts of the impeller back plate that are under great stress and have weak strength and therefore need to be reinforced. By locally strengthening the weak parts of the impeller back plate, the overall weight of the fan impeller can be reduced. This has important guiding significance for improving the stability of the fan impeller and reducing the manufacturing cost in actual production.

[0023] (2) The rear disc patch is attached to the impeller rear disc and welded together. By using the method of patching the rear disc in a local area, the structure is relatively simple, and it is convenient to weld and manufacture on site. The cost is low and the processing is simple. Compared with the traditional overall thickened rear disc, it effectively saves material costs. Compared with the processing of conical rear disc, it reduces the process of turning the conical disc, thus eliminating processing costs. At the same time, the production cycle is short.

[0024] (3) Topology optimization is performed on the fan impeller model that fails the simulation verification. Although the fan impeller will be thinned in the optimization design, the material distribution can be ensured to meet the strength requirements through precise topology optimization, and structural failure caused by material reduction can be avoided. According to the stress area display, the back plate patch is used to thicken the middle area of ​​the impeller back plate to improve the stress situation of the impeller back plate and increase its strength.

[0025] (4) By performing topology optimization analysis on the impeller structure, the material distribution of the structure is determined. The impeller structure of the ventilator is designed according to the topology optimization results, which can reduce the overall weight of the ventilator impeller. This is of great significance to the operation of the ventilator, especially in applications that require high speed. Lightweight design can reduce rotational inertia, thereby improving response speed and stability. Optimized design can reduce the use of materials while ensuring structural strength and stiffness, which helps to reduce production costs.

[0026] (5) The optimized impeller structure is re-simulated and verified until it passes the verification. The optimized structure is verified by finite element analysis to ensure that it can maintain good deformation resistance and stability under various working conditions. This method can minimize the size of the thickened area of ​​the impeller back plate, effectively save material and manufacturing costs, and has good economic efficiency and practicality. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below:

[0028] Figure 1 A flowchart illustrating the method for reinforcing the rear disc of a ventilation fan impeller. Detailed Implementation

[0029] To better understand the above-mentioned objectives, features and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways than those described herein, and therefore the invention is not limited to the specific embodiments disclosed in the following specification.

[0031] Example 1

[0032] The following is combined Figure 1 Specific instructions on how to reinforce the rear disc of the fan impeller, such as... Figure 1 As shown, a method for reinforcing the rear disc of a ventilator impeller includes a rear disc and a shaft disc, wherein the rear disc and the shaft disc are detachably connected. The impeller also includes a rear disc patch, which is welded to the rear disc. The method for reinforcing the rear disc of the ventilator impeller includes the following steps:

[0033] Step 1: Perform strength analysis on the fan impeller using finite element analysis to verify whether the material strength meets the structural requirements. Based on the stress conditions of the fan impeller, establish a finite element simulation model.

[0034] Step 2: Perform topology optimization on the fan impeller model that fails the simulation verification. By performing topology optimization analysis on the fan impeller structure, determine the material distribution of the structure.

[0035] Step 3: Design the rear disk patch based on the topology optimization results. Combine the stress distribution in the simulation results and the material distribution of the impeller rear disk in the topology optimization, and reinforce the impeller rear disk with the rear disk patch. The optimized impeller structure is then re-simulated and verified until it passes the verification.

[0036] Step one includes: designing the structure of the fan impeller to obtain a three-dimensional model of the fan impeller; obtaining the material parameters and operating condition parameters of the designed fan impeller; using finite element analysis software, importing the material parameters and operating condition parameters of the fan impeller into the finite element analysis software to establish a finite element simulation model; calculating the structural strength of the fan impeller based on the finite element simulation model, and setting boundary conditions according to the rotational conditions of the fan impeller; analyzing the overall stress on the fan impeller and selecting the impeller back plate for analysis.

[0037] The material parameters and operating parameters of the fan impeller include the density, elastic modulus, Poisson's ratio, rotational speed, and gravitational acceleration of the fan impeller material.

[0038] By calculating the stress on the fan impeller under centrifugal force and gravity load, this value is compared with the yield strength of the fan impeller material.

[0039] The shaft disk and the impeller rear disk are connected by bolts. In the finite element simulation model, the bolt connection between the shaft disk and the impeller rear disk is simplified to two-sided bonding, that is, using a tie for binding connection.

[0040] Step two includes the following steps: obtaining the optimized fan impeller material parameters and operating condition parameters; using finite element optimization software, importing the fan impeller material parameters and operating condition parameters into the finite element optimization software to establish a topology optimization model; seeking the material distribution based on the topology optimization model, and setting boundary conditions based on the fan impeller rotation conditions; defining the design variables for topology optimization, setting the optimization response for topology optimization, setting the optimization constraints for topology optimization, setting the optimization objective for topology optimization, and redesigning the structure based on the topology optimization results.

[0041] The design variables for topology optimization include defining minimum size constraints, maximum size constraints, and symmetry constraints;

[0042] The optimized response of the topology optimization includes defining the volume fraction response, compliance response, and stress response;

[0043] The optimization constraints for the topology optimization include defining minimum size constraints, maximum size constraints, and symmetry constraints.

[0044] The optimization objectives of the topology optimization include minimum compliance corresponding to maximum stiffness, and defining the impeller structure as having minimum compliance.

[0045] Obtain the optimized fan impeller material parameters and operating condition parameters, including the fan impeller material density, elastic modulus, Poisson's ratio, and rotational speed, and set the material properties for the design domain and non-design domain.

[0046] Calculate the overall stress on the fan impeller under centrifugal load, and distribute the material according to the stress magnitude.

[0047] Step 3 involves attaching a back plate patch to the impeller back plate. The diameter of the back plate patch is determined according to the material distribution of topology optimization. The back plate patch is attached to and welded to the impeller back plate. The back plate patch and the impeller back plate have the same size inner hole, and the inner hole of the back plate patch and the inner hole of the impeller back plate are located on the same axis. Then, the optimized structure is simulated and verified to obtain a fan impeller with sufficient strength.

[0048] When comparing the magnitude of the stress on the overall fan impeller with the yield strength of the fan impeller material, a safety factor of 1.3 is retained, and the ratio of the material yield strength to 1.3 times the yield strength of the fan impeller material is used as the evaluation standard value for the strength of the fan impeller.

[0049] Topology optimization is a mathematical method that optimizes the distribution of materials within a given region based on given load conditions, constraints, and performance indicators. It is a type of structural optimization.

[0050] Boundary conditions are used to constrain the movement and rotation of the fan impeller during topology optimization. Boundary conditions are applied to the finite element optimization model, and the impeller is then topologically optimized using this model to obtain the most reasonable material distribution. Finite element optimization specifically involves material allocation based on analyzing the response of the fan impeller to centrifugal loads during operation. Design variables for topology optimization are set, including optimization response, optimization constraints, and optimization objectives. Topology optimization is a structural optimization method based on the variable density method. This method achieves design objectives, such as increasing strength, reducing weight, or improving performance, by adjusting the density distribution of materials within the design domain. The variable density method represents the material distribution by assigning a material density value to each cell in the design domain. During optimization, the density values ​​are adjusted according to the optimization objectives and constraints to obtain the optimal material distribution scheme.

[0051] In finite element simulation, a tie constraint is a boundary condition used to define the relationship between different components or regions. The main function of a tie is to connect two or more surfaces together, so that these connected parts behave like a continuum during the analysis. This constraint forces the bound surfaces to maintain consistent displacement, ensuring that there is no relative slippage or separation during loading and deformation.

[0052] Design variables are defined in topology optimization. In topology optimization, design variables are key factors used to describe changes in structural shape. Design variables determine the distribution of materials in the design domain and are parameters that need to be adjusted during the optimization process. By changing the values ​​of design variables, different material distribution schemes can be obtained, thereby finding the optimal structural topology.

[0053] Setting the optimization response in topology optimization is an indicator used to measure the quality of a design. The optimization response is an output quantity generated based on changes in design variables. By setting these responses, the topology optimization process can be guided in the desired direction to meet specific design objectives.

[0054] Setting optimization constraints in topology optimization involves defining the limitations on the optimization process. These constraints ensure that the optimized design meets performance requirements while also complying with various constraints in practical engineering, such as requirements for manufacturing processes, material properties, and structural integrity. Optimization constraints and optimization responses are closely related, and together they guide the topology optimization algorithm to find a feasible and reasonable optimal solution.

[0055] The optimization objective of topology optimization is a mathematical description of the final state that is expected to be achieved in the entire optimization process. The optimization objective clarifies the direction of the design and is the pursuit of achieving the optimal performance index under various constraints.

[0056] The boundary conditions are used to constrain the movement and rotation of the fan impeller during the calculation of the impeller structural strength. Boundary conditions are applied to the finite element analysis model, and the structural strength of the fan impeller is analyzed using the finite element analysis model with the boundary conditions applied. The structural strength of the fan impeller is calculated. Specifically, the finite element analysis is performed by simulating and analyzing the response of the fan impeller under centrifugal force load and gravity load during operation. Specifically, the magnitude of the stress on the impeller is calculated based on the given centrifugal force and gravitational acceleration.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for reinforcing the rear disc of a ventilator impeller, wherein the ventilator impeller to be reinforced includes an impeller rear disc and a shaft disc, wherein the impeller rear disc and the shaft disc are detachably connected, characterized in that: The fan impeller to be reinforced also includes a rear disc patch, which is welded to the rear disc of the impeller. The method for reinforcing the rear disc of the fan impeller includes the following steps: Step 1: Perform strength analysis on the fan impeller using finite element analysis to verify whether the material strength meets the structural requirements. Based on the stress conditions of the fan impeller, establish a finite element simulation model. Step 2: Perform topology optimization on the fan impeller model that fails the simulation verification. By performing topology optimization analysis on the fan impeller structure, determine the material distribution of the structure. Step 3: Design the rear disk patch based on the topology optimization results. Combine the stress distribution in the simulation results and the material distribution of the impeller rear disk in the topology optimization, and reinforce the impeller rear disk with the rear disk patch. The optimized impeller structure is then re-simulated and verified until the verification passes. Step one includes: designing the structure of the fan impeller to obtain a three-dimensional model of the fan impeller; obtaining the material parameters and operating condition parameters of the designed fan impeller; using finite element analysis software, importing the material parameters and operating condition parameters of the fan impeller into the finite element analysis software to establish a finite element simulation model; calculating the structural strength of the fan impeller based on the finite element simulation model, and setting boundary conditions according to the rotational conditions of the fan impeller; analyzing the overall stress on the fan impeller and selecting the impeller back plate for analysis; The material parameters and operating parameters of the fan impeller include the density, elastic modulus, Poisson's ratio, rotational speed, and gravitational acceleration of the fan impeller material; By calculating the stress on the fan impeller under centrifugal force and gravity load, this value is compared with the yield strength of the fan impeller material. Step two includes the following steps: obtaining the optimized fan impeller material parameters and operating condition parameters; using finite element optimization software, importing the fan impeller material parameters and operating condition parameters into the finite element optimization software to establish a topology optimization model; seeking the material distribution based on the topology optimization model, and setting boundary conditions based on the fan impeller rotation conditions; defining the design variables for topology optimization, setting the optimization response for topology optimization, setting the optimization constraints for topology optimization, setting the optimization objective for topology optimization, and redesigning the structure based on the topology optimization results; Calculate the overall stress on the fan impeller under centrifugal load, and distribute the material according to the stress magnitude; Step 3 involves attaching a back plate patch to the impeller back plate. The diameter of the back plate patch is determined according to the material distribution of topology optimization. The back plate patch is attached to and welded to the impeller back plate. The back plate patch and the impeller back plate have the same size inner hole, and the inner hole of the back plate patch and the inner hole of the impeller back plate are located on the same axis. Then, the optimized structure is simulated and verified to obtain a fan impeller with sufficient strength.

2. The method for reinforcing the rear disc of a ventilation fan impeller according to claim 1, characterized in that: The shaft disk and the impeller rear disk are connected by bolts. In the finite element simulation model, the bolt connection between the shaft disk and the impeller rear disk is simplified to two-sided bonding, that is, using a tie for binding connection. In finite element simulation, a tie constraint is a boundary condition used to define the relationship between different components or regions. The main function of a tie is to connect two or more surfaces together, so that these connected parts behave like a continuum during the analysis. This constraint forces the bound surfaces to maintain consistent displacement, ensuring that there is no relative slippage or separation during loading and deformation.

3. The method for reinforcing the rear disc of a ventilation fan impeller according to claim 1, characterized in that: The design variables for topology optimization include defining minimum size constraints, maximum size constraints, and symmetry constraints; The optimized response of the topology optimization includes defining the volume fraction response, compliance response, and stress response; The optimization constraints for the topology optimization include defining minimum size constraints, maximum size constraints, and symmetry constraints. The optimization objectives of the topology optimization include minimum compliance corresponding to maximum stiffness, and defining the impeller structure as having minimum compliance.

4. The method for reinforcing the rear disc of a ventilator impeller according to claim 1, characterized in that: Obtain the optimized fan impeller material parameters and operating condition parameters, including the fan impeller material density, elastic modulus, Poisson's ratio, and rotational speed, and set the material properties for the design domain and non-design domain.

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