Method for reinforcing impeller rear disc of ventilator

Abstract

The invention belongs to the technical field of ventilators, and particularly relates to a ventilator impeller rear disc reinforcing method. The method includes the following steps of firstly, conducting strength analysis on the ventilator impeller through finite element analysis, and establishing a finite element simulation model, secondly, conducting topological optimization on the ventilator impeller model which does not pass simulation checking, conducting topological optimization analysis on the ventilator impeller structure, determining material distribution of the structure, and calculating the structure of the ventilator impeller according to the material distribution. 3, designing a rear disc patch according to a topological optimization result, reinforcing the rear disc of the impeller through the rear disc patch, and performing simulation check on the optimized impeller structure again until the check is passed; compared with the prior art, the method has the advantages and positive effects that the part, which is large in stress, low in strength and further required to be reinforced, of the impeller rear disc can be visually found out, and the weight of the fan impeller is reduced by locally reinforcing the weak part of the impeller rear disc.

Description

Technical Field

[0001] The invention belongs to the technical field of ventilators, and in particular relates to a method for reinforcing a rear disc of an impeller of a ventilator. Background Art

[0002] During the fan structure design process, the strength of the fan impeller must be checked. The traditional checking method can only check the wheel cover, blades, and rear disc as a whole. It is impossible to intuitively determine the strength of each component or the magnitude of the force. As a result, when it is checked that the strength of the rear disc is not enough, the entire rear disc is usually thickened. Since the rear disc is the component on the impeller that connects the front disc and blades and transmits torque, its thickness is thicker than the front disc and blades, and it accounts for a large proportion of the impeller weight. The overall thickening of the rear disc will lead to a significant increase in the weight of the entire impeller, which in turn leads to a large starting torque of the impeller. On the one hand, it prolongs the starting time of the fan and causes severe heating of the motor when the fan starts; on the other hand, it increases the force on the main shaft and the load on the bearings, which increases the cost.

[0003] In addition, the increase in the weight of the impeller rear disc will lead to a decrease in safety and stability. Therefore, there is an urgent need for a fan impeller rear disc reinforcement method with low impeller rear disc weight and high stability. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for reinforcing a rear disc of an impeller of a fan.

[0005] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is: a method for reinforcing the rear disc of a ventilator impeller, the ventilator impeller to be reinforced comprises an impeller rear disc and a shaft disc, the impeller rear disc and the shaft disc are detachably connected, the ventilator impeller to be reinforced also comprises a rear disc patch, the rear disc patch is welded to the impeller rear disc, and the ventilator impeller rear disc reinforcement method comprises the following steps: Step 1: Perform strength analysis on the fan impeller through finite element analysis to check whether the material strength meets the structural requirements, and establish a finite element simulation model based on the stress conditions of the fan impeller; Step 2: Perform topology optimization on the fan impeller model that fails the simulation verification, and determine the material distribution of the structure by performing topology optimization analysis on the fan impeller structure; Step 3: Design the rear disc patch according to the results of topology optimization. Combined with the stress distribution in the simulation results and the material distribution of the impeller rear disc in the topology optimization, the impeller rear disc is reinforced by the rear disc patch. The optimized impeller structure is re-simulated and checked until it passes the check.

[0006] Preferably, step one includes: structurally designing the fan impeller to obtain a three-dimensional model of the fan impeller; obtaining 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, and establishing a finite element simulation model; calculating the structural strength of the fan impeller according to the finite element simulation model, and setting boundary conditions according to the rotation conditions of the fan impeller; analyzing the overall stress condition of the fan impeller and selecting the impeller rear disc for analysis.

[0007] Preferably, the fan impeller material parameters and operating condition parameters include the density, elastic modulus, Poisson's ratio, rotation speed and gravitational acceleration of the fan impeller material.

[0008] Preferably, the stress on the entire fan impeller under centrifugal force and gravity load is calculated, and the value is compared with the yield limit of the fan impeller material.

[0009] Preferably, the shaft disc is connected to the impeller rear disc by bolts, and the bolt connection between the shaft disc and the impeller rear disc is simplified to two-sided fitting in the finite element simulation model, that is, a binding connection is performed using Tie.

[0010] Preferably, step 2 includes the following steps: obtaining the optimized material parameters and operating condition parameters of the fan impeller; using finite element optimization software, importing the material parameters and operating condition parameters of the fan impeller into the finite element optimization software, and establishing a topology optimization model; seeking material distribution according to the topology optimization model, and setting boundary conditions according to the rotation conditions of the fan impeller; defining design variables for topology optimization, setting the optimization response of topology optimization, setting the optimization constraints of topology optimization, setting the optimization goals of topology optimization, and redesigning the structure according to the topology optimization results.

[0011] Preferably, the design variables of the topology optimization include defining a minimum size constraint, a maximum size constraint and a symmetry constraint; The optimization response of the topology optimization includes defining volume fraction response, compliance response and stress response; The optimization constraints of the topology optimization include defining a minimum size constraint, a maximum size constraint and a symmetry constraint; The optimization goal of the topology optimization includes minimum flexibility corresponding to maximum stiffness, and defines that the impeller structure has minimum flexibility.

[0012] Preferably, the optimized fan impeller material parameters and operating condition parameters 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 the non-design domain are set.

[0013] Preferably, the stress on the entire fan impeller under the centrifugal load is calculated, and the material distribution is performed according to the stress.

[0014] Preferably, step three includes attaching a rear disc patch to the rear disc of the impeller, the diameter of the rear disc patch is determined according to the material distribution of topological optimization, the rear disc patch is attached to and welded to the rear disc of the impeller, the rear disc patch and the rear disc of the impeller have an inner hole of the same size, and the inner hole of the rear disc patch and the inner hole of the rear disc of the impeller are located on the same axis, and then the optimized structure is simulated and verified to obtain a fan impeller with strength that meets the requirements.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are: (1) Strength analysis of the fan impeller through finite element analysis can directly reflect the stress condition of the fan impeller. Topological optimization of the fan impeller model that fails the simulation verification can directly find out the parts of the impeller rear disc that are subjected to large forces and weak strength and need to be reinforced. By locally strengthening the weak parts of the impeller rear disc, the overall weight of the fan impeller can be reduced, which has important guiding significance for improving the stability of the fan impeller and reducing the production cost in actual production; (2) The rear disc patch is bonded and welded to the impeller rear disc. By using the method of bonding the plate in the local area of ​​the rear disc, 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 processing a tapered rear disc, it reduces the process of turning the tapered disc and thus has no processing cost. At the same time, the production period is short. (3) Topological optimization was performed on the fan impeller model that failed the simulation verification. Although the fan impeller would be thinner in the optimized design, accurate topological optimization could ensure that the material distribution met the strength requirements and avoid structural failure caused by material reduction. According to the stress area display, the middle area of ​​the impeller rear disc was thickened by attaching a patch to the rear disc to improve the stress condition of the impeller rear disc and increase its strength. (4) By performing topological optimization analysis on the impeller structure and determining the material distribution of the structure, the fan impeller structure can be designed according to the topological optimization results, which can reduce the overall weight of the fan impeller. This is of great significance to the operation of the fan, especially in applications that require high speeds. Lightweight design can reduce the moment of inertia, thereby improving response speed and stability. The optimized design can reduce the use of materials while ensuring structural strength and stiffness, which helps to reduce production costs. (5) The optimized impeller structure is re-simulated and checked until it passes the check. The optimized structure is verified by the finite element analysis method to ensure that it can maintain good anti-deformation ability and stability under various working conditions. This method can minimize the area of ​​thickening of the impeller rear disc, effectively save material costs and production costs, and has good economy and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following is a brief introduction to the drawings required for describing the embodiment: Figure 1 This is a flowchart of the fan impeller rear disc reinforcement method. DETAILED DESCRIPTION

[0017] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below with reference to the accompanying drawings and embodiments.

[0018] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0019] Example 1 Combine the following Figure 1 Specifically explain the method of reinforcing the rear disc of the fan impeller, such as Figure 1 As shown, a method for reinforcing the rear disc of a ventilator impeller is provided. 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. The ventilator impeller to be reinforced also includes a rear disc patch, wherein the rear disc patch is welded to the impeller rear disc. The method for reinforcing the rear disc of the ventilator impeller includes the following steps: Step 1: Perform strength analysis on the fan impeller through finite element analysis to check whether the material strength meets the structural requirements, and establish a finite element simulation model based on the stress conditions of the fan impeller; Step 2: Perform topology optimization on the fan impeller model that fails the simulation verification, and determine the material distribution of the structure by performing topology optimization analysis on the fan impeller structure; Step 3: Design the rear disc patch according to the results of topology optimization. Combined with the stress distribution in the simulation results and the material distribution of the impeller rear disc in the topology optimization, the impeller rear disc is reinforced by the rear disc patch. The optimized impeller structure is re-simulated and checked until it passes the check.

[0020] Step one includes: structurally designing the fan impeller to obtain a three-dimensional model of the fan impeller; obtaining 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, and establishing a finite element simulation model; calculating the structural strength of the fan impeller according to the finite element simulation model, and setting boundary conditions according to the rotation conditions of the fan impeller; analyzing the overall stress condition of the fan impeller and selecting the impeller rear disc for analysis.

[0021] The fan impeller material parameters and operating condition parameters include the density, elastic modulus, Poisson's ratio, rotation speed and gravitational acceleration of the fan impeller material.

[0022] By calculating the stress on the fan impeller as a whole under centrifugal force and gravity load, this value is compared with the yield limit of the fan impeller material.

[0023] The shaft disc and the impeller rear disc are connected by bolts. The bolt connection between the shaft disc and the impeller rear disc is simplified to two-sided fitting in the finite element simulation model, that is, Tie is used for binding connection.

[0024] Step 2 includes the following steps: obtaining the optimized material parameters and operating condition parameters of the fan impeller; using finite element optimization software, importing the material parameters and operating condition parameters of the fan impeller into the finite element optimization software, and establishing a topology optimization model; seeking material distribution according to the topology optimization model, and setting boundary conditions according to the rotation conditions of the fan impeller; defining the design variables of the topology optimization, setting the optimization response of the topology optimization, setting the optimization constraints of the topology optimization, setting the optimization goals of the topology optimization, and redesigning the structure according to the topology optimization results.

[0025] The design variables of the topology optimization include defining a minimum size constraint, a maximum size constraint and a symmetry constraint; The optimization response of the topology optimization includes defining volume fraction response, compliance response and stress response; The optimization constraints of the topology optimization include defining a minimum size constraint, a maximum size constraint and a symmetry constraint; The optimization goal of the topology optimization includes minimum flexibility corresponding to maximum stiffness, and defines that the impeller structure has minimum flexibility.

[0026] Obtain the optimized fan impeller material parameters and operating condition parameters, including the density, elastic modulus, Poisson's ratio and rotation speed of the fan impeller material, and set the material properties of the design domain and non-design domain.

[0027] Calculate the stress on the fan impeller as a whole under the centrifugal load, and distribute the material according to the stress.

[0028] Step three includes attaching a rear disc patch to the rear disc of the impeller. The diameter of the rear disc patch is determined according to the material distribution of topological optimization. The rear disc patch is attached to and welded to the rear disc of the impeller. The rear disc patch and the rear disc of the impeller have an inner hole of the same size, and the inner hole of the rear disc patch and the inner hole of the rear disc of the impeller are located on the same axis. The optimized structure is then simulated and verified to obtain a fan impeller with strength that meets the requirements.

[0029] When comparing the stress magnitude of the entire fan impeller with the yield limit of the fan impeller material, a safety factor of 1.3 times is retained, and the ratio of the material yield strength to 1.3 times the yield limit of the fan impeller material is used as the standard value for evaluating the fan impeller strength.

[0030] Topology optimization is a mathematical method that optimizes material distribution in a given area based on given load conditions, constraints and performance indicators. It is a type of structural optimization.

[0031] Boundary conditions are used to constrain the movement and rotation of the fan impeller during the topology optimization process. Boundary conditions are imposed on the finite element optimization model. The fan impeller is topologically optimized using the finite element optimization model with imposed boundary conditions to obtain the most reasonable material distribution. Finite element optimization is specifically based on analyzing the response of the fan impeller to the centrifugal load during operation to distribute materials, set the design variables for topology optimization, optimize the response, optimize the constraints, and optimize the goals. Topology optimization is a structural optimization method based on the variable density method. This method achieves design goals by adjusting the density distribution of materials in the design area, such as increasing strength, reducing weight, or improving performance. The variable density method represents the distribution of materials by assigning a material density value to each cell in the design domain. During the optimization process, the density value will be adjusted according to the optimization goal and constraints to obtain the best material distribution plan.

[0032] In finite element simulation, Tie constraint is a boundary condition used to define the relationship between different parts or regions. The main function of Tie is to connect two or more surfaces together so that these connected parts behave like a continuum during the analysis process. This constraint forces the bound surfaces to remain consistent in displacement to ensure that there is no relative sliding or separation during loading and deformation.

[0033] Define the design variables for 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.

[0034] Set the optimization response of topology optimization. The optimization response in topology optimization is an indicator used to measure the quality of the design scheme. The optimization response of topology optimization is an output generated based on the change of design variables. By setting these responses, the topology optimization process can be guided in the desired direction to meet specific design goals.

[0035] Set the optimization constraints for topology optimization. The optimization constraints in topology optimization are the restrictions on the optimization process. These constraints ensure that the optimized design not only meets the performance requirements, but also complies with various restrictions in actual engineering, such as manufacturing process, material properties, structural integrity and other aspects. The optimization constraints are closely related to the optimization response. The optimization constraints and the optimization response jointly guide the topology optimization algorithm to find a feasible and reasonable optimal solution.

[0036] Set the optimization goal of topology optimization. The optimization goal of topology optimization is a mathematical description of the final state that the entire optimization process expects to achieve. The optimization goal clarifies the direction of the design and is to achieve the optimal goal of one or more performance indicators while satisfying various constraints.

[0037] The boundary conditions are used to constrain the movement and rotation of the fan impeller in the process of calculating the structural strength of the impeller; the boundary conditions are applied to the finite element analysis model, and the structural strength analysis of the fan impeller is performed using the finite element analysis model to which the boundary conditions are applied, and the structural strength of the fan impeller is calculated. The finite element analysis is specifically performed by simulating and analyzing the response of the fan impeller under the centrifugal force load and gravity load during operation, and specifically calculating the magnitude of the stress on the impeller based on the given centrifugal force and gravitational acceleration.

[0038] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes for application in other fields. However, any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for reinforcing a rear disc of a ventilator impeller, wherein the ventilator impeller to be reinforced comprises an impeller rear disc and a shaft disc, wherein the impeller rear disc and the shaft disc are detachably connected, and wherein: The fan impeller to be reinforced also includes a rear disc patch, which is welded to the impeller rear disc. The fan impeller rear disc reinforcement method includes the following steps: Step 1: Perform strength analysis on the fan impeller through finite element analysis to check whether the material strength meets the structural requirements, and establish a finite element simulation model based on the stress conditions of the fan impeller; Step 2: Perform topology optimization on the fan impeller model that fails the simulation verification, and determine the material distribution of the structure by performing topology optimization analysis on the fan impeller structure; Step 3: Design the rear disc patch according to the results of topology optimization. Combined with the stress distribution in the simulation results and the material distribution of the impeller rear disc in the topology optimization, the impeller rear disc is reinforced by the rear disc patch. The optimized impeller structure is re-simulated and checked until it passes the check.

2. A method for reinforcing the rear disc of a ventilator impeller according to claim 1, characterized in that: Step one includes: structurally designing the fan impeller to obtain a three-dimensional model of the fan impeller; obtaining 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, and establishing a finite element simulation model; calculating the structural strength of the fan impeller according to the finite element simulation model, and setting boundary conditions according to the rotation conditions of the fan impeller; analyzing the overall stress condition of the fan impeller and selecting the impeller rear disc for analysis.

3. A method for reinforcing the rear disc of a ventilator impeller according to claim 2, characterized in that: The fan impeller material parameters and operating condition parameters include the density, elastic modulus, Poisson's ratio, rotation speed and gravitational acceleration of the fan impeller material.

4. A method for reinforcing the rear disc of a ventilator impeller according to claim 2, characterized in that: By calculating the stress on the fan impeller as a whole under centrifugal force and gravity load, this value is compared with the yield limit of the fan impeller material.

5. A method for reinforcing the rear disc of a ventilator impeller according to claim 2, characterized in that: The shaft disc and the impeller rear disc are connected by bolts. The bolt connection between the shaft disc and the impeller rear disc is simplified to two-sided fitting in the finite element simulation model, that is, Tie is used for binding connection.

6. A method for reinforcing the rear disc of a ventilator impeller according to claim 1, characterized in that: Step 2 includes the following steps: obtaining the optimized material parameters and operating condition parameters of the fan impeller; using finite element optimization software, importing the material parameters and operating condition parameters of the fan impeller into the finite element optimization software, and establishing a topology optimization model; seeking material distribution according to the topology optimization model, and setting boundary conditions according to the rotation conditions of the fan impeller; defining the design variables of the topology optimization, setting the optimization response of the topology optimization, setting the optimization constraints of the topology optimization, setting the optimization goals of the topology optimization, and redesigning the structure according to the topology optimization results.

7. A method for reinforcing the rear disc of a ventilator impeller according to claim 6, characterized in that: The design variables of the topology optimization include defining a minimum size constraint, a maximum size constraint and a symmetry constraint; The optimization response of the topology optimization includes defining volume fraction response, compliance response and stress response; The optimization constraints of the topology optimization include defining a minimum size constraint, a maximum size constraint and a symmetry constraint; The optimization goal of the topology optimization includes minimum flexibility corresponding to maximum stiffness, and defines that the impeller structure has minimum flexibility.

8. A method for reinforcing the rear disc of a ventilator impeller according to claim 6, characterized in that: Obtain the optimized fan impeller material parameters and operating condition parameters, including the density, elastic modulus, Poisson's ratio and rotation speed of the fan impeller material, and set the material properties of the design domain and non-design domain.

9. A method for reinforcing the rear disc of a ventilator impeller according to claim 6, characterized in that: Calculate the stress on the fan impeller as a whole under the centrifugal load, and distribute the material according to the stress.

10. A method for reinforcing the rear disc of a ventilator impeller according to claim 1, characterized in that: Step three includes attaching a rear disc patch to the rear disc of the impeller. The diameter of the rear disc patch is determined according to the material distribution of topological optimization. The rear disc patch is attached to and welded to the rear disc of the impeller. The rear disc patch and the rear disc of the impeller have an inner hole of the same size, and the inner hole of the rear disc patch and the inner hole of the rear disc of the impeller are located on the same axis. The optimized structure is then simulated and verified to obtain a fan impeller with strength that meets the requirements.

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