Method for determining distribution positions of supporting rods of fan shell by utilizing finite element analysis

Abstract

The invention belongs to the field of centrifugal fan casing manufacturing, and particularly relates to a method for determining the distribution position of a fan casing supporting rod by utilizing finite element analysis, which comprises the following steps of: 1, building a three-dimensional model of a fan casing according to customer requirements, importing fan performance parameters in a fan type selection report into finite element analysis software, and establishing a three-dimensional model of the fan casing; establishing a finite element simulation model of the ventilator casing through finite element analysis software; 2, applying boundary conditions to the finite element simulation model to perform simulation test on the structural strength of the ventilator casing; 3, supporting rods are installed at the positions, with the large deformation quantity, of the ventilator shell in the simulation test; the invention provides a fan shell finite element calculation method and a centrifugal fan shell side plate supporting device to solve the problems that in the prior art, due to the fact that a shell steel plate is thinned and the deformation amount of a shell side plate is increased, the operation stability and safety of a fan are poor.

Description

Technical Field

[0001] The invention relates to the field of centrifugal fan casing manufacturing, and in particular to a method for determining the distribution positions of support rods of a fan casing by using finite element analysis. Background Art

[0002] Manufacturing is an important pillar of a country's economic development and is known as the foundation of a country and the basis of a strong country. With the increasing pressure on the global response to climate change, achieving carbon peak and carbon neutrality (dual carbon) goals has become an important task for all countries. For China, carbon emission reduction in the manufacturing industry is particularly critical and is one of the important ways to achieve the dual carbon goals. In this context, energy conservation and emission reduction have become a means of "peaking", while energy substitution is a way to achieve "neutralization", and technological upgrading is the key to achieving the "dual carbon" goals.

[0003] The traditional centrifugal fan has a bulky structure and uses more plates than is actually needed. This not only increases production costs, but also wastes resources and fails to meet the requirements of energy conservation and emission reduction. In addition, the use of too many plates does not significantly improve the performance of the fan, but may instead cause new problems due to the non-optimal use of materials.

[0004] When trying to reduce the thickness of the plate, although it can save steel plate materials, the problem that follows is that the deformation of the casing side plate at the fan inlet installation position increases, affecting the safety and stability of the fan. Therefore, it is necessary to find a way to reduce the use of materials while ensuring the structural strength and stability of the fan.

[0005] Therefore, in response to the above-mentioned problems, a method for determining the distribution position of fan casing support rods using finite element analysis is proposed. Summary of the invention

[0006] The present invention is aimed at the above-mentioned problems and specifically designs a method for determining the distribution position of the fan casing support rods using finite element analysis, provides a fan casing finite element calculation method and a centrifugal fan casing side panel support device, so as to solve the problem in the prior art that the casing steel plate is thinned and the deformation of the casing side panel is increased, resulting in poor fan operation stability and safety.

[0007] To achieve the above object, the present invention provides a method for determining the distribution position of fan casing support rods using finite element analysis, comprising the following steps: Step 1: Build a three-dimensional model of the fan casing according to customer needs, import the fan performance parameters in the fan selection report into the finite element analysis software, and use the finite element analysis software to build a finite element simulation model of the fan casing; Step 2: Performing a simulation test on the structural strength of the fan casing by applying boundary conditions to the finite element simulation model; Step three: Install support rods at the positions of the fan casings with large deformation in the simulation test. Save the three-dimensional model generated by the design software as a step format file, then perform geometric cleaning and component assembly in the finite element pre-processing software, extract the mid-surface of the sorted geometric structure, and then divide the shell mesh. Compared with the solid mesh, the shell mesh can greatly reduce the number of units and nodes, thereby improving the calculation efficiency. Apply wind pressure loads to the inner surface of the fan casing 1, and the fan flanges need to be bound and connected. Sharing a node between wind pressure and binding will cause algorithm errors, which is time-consuming and laborious to handle. Therefore, the casing and the reinforcement are separated, and the casing is combined into a whole. The reinforcement is bound, and the high-order tetrahedral solid mesh is divided in this way.

[0008] In the above manner, the finite element analysis software can be used to simulate and calculate the working state of the fan casing in a specified environment, and support components can be installed at locations with large deformation to support the plate, strengthen the overall structure, reduce the deformation, and improve structural stability.

[0009] Furthermore, in step 2, the boundary conditions are used to constrain the movement and rotation of the fan casing in the process of calculating the casing structural strength, and the mounting base located on the side of the fan casing is the constraint point of the boundary conditions. Boundary conditions are set according to the structural characteristics and load characteristics of the fan during operation, and the boundary conditions are applied to the finite element analysis model to calculate the structural strength of the fan casing.

[0010] Furthermore, the simulation test in step 2 includes: simulating the response of the fan casing under the wind pressure load and gravity load during operation by finite element analysis software; automatically calculating the stress and deformation of the fan casing according to the given wind pressure. Calculate the position of the fan casing with the largest deformation according to the data in the software simulated working environment.

[0011] Furthermore, in the step one, the fan performance parameters in the fan selection report include the fan's inlet static pressure, outlet static pressure, outlet total pressure, and material performance parameters.

[0012] Furthermore, when the finite element simulation model is created using finite element analysis software in step one, it also includes welding connections between various welding components, binding connections of mounting surfaces, equivalent mass points of air dampers and bellows, displacement constraints of mounting bases, application of wind pressure loads on the inner surface of the fan, and assignment of material performance parameters.

[0013] Furthermore, in step three, the deformation in the simulation test is the plate deformation of the fan casing, and the deformation at the air inlet of the fan casing is the largest. By calculating the casing under wind pressure and gravity load, the stress on the casing as a whole is far less than the yield limit of the material. However, the local deformation of the fan casing 1 has exceeded the plate thickness. In order to prevent the fan failure and damage problems that may be caused by large deformation, the maximum deformation of the fan needs to be reduced. Therefore, the subsequent work only uses the deformation of the fan plate as the evaluation standard for the quality of the fan casing.

[0014] Furthermore, by checking the deformation of the entire fan housing, the displacement of the upper part of the air inlet is the largest, and a support rod is arranged and installed at the position with the largest displacement. There are two support rods, two support rods are installed in each air inlet, and the two support rods are located in the same horizontal plane and parallel to each other.

[0015] The present invention also proposes a support and adjustment assembly for preventing deformation at the air inlet of the fan, including a support assembly for preventing deformation of the air inlet, the support assembly comprising: a support rod, an air inlet box side panel and a casing side panel, the air inlet box side panel is located on the outer side of the air inlet box, the casing side panel is located between the volute and the air inlet box, and the two ends of the support rod are fixedly connected between the air inlet box side panel and the casing side panel.

[0016] Furthermore, there are a plurality of support rods, and the plurality of support rods are evenly arranged on the upper portion of the air inlet.

[0017] Furthermore, the support rod is a cylindrical steel pipe.

[0018] In summary, the method for determining the distribution position of the fan casing support rods by using finite element analysis of the present invention has the following advantages and beneficial technical effects: 1. The position, quantity and structure of the support and regulating pipes are accurately analyzed and designed through finite element calculation, which effectively prevents the deformation of the fan air inlet caused by wind pressure and improves the stability and safety of the overall structure; 2. Finite element method is used to accurately calculate and design the layout of the support and regulating pipes, and the material usage is reasonably allocated, which minimizes the waste of materials, improves the utilization rate of materials, and meets the requirements of energy conservation and emission reduction; 3. The scientific design of the support and adjustment pipe can effectively disperse and balance the wind pressure when the fan is working, reduce the impact on the air inlet, improve the fan's ability to resist wind pressure, and ensure the stable operation of the ventilation system; 4. By preventing structural deformation and displacement, the support and adjustment pipe effectively protects the important parts of the fan, reduces damage caused by deformation, extends the service life of the equipment, and reduces maintenance and replacement costs; 5. The reasonable design and layout of the support and adjustment pipe not only enhances the stability of the fan, but also reduces the failure rate caused by structural deformation, improves the stability and reliability of the equipment, and thus improves production efficiency; 6. After implementing the technical solution of the present invention, the deformation of the side panel of the casing is 15.2 mm without adding support rods, and the displacement is reduced to only 4.5 mm after adding two support rods. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 It is a schematic diagram of the positions of various structural components on the housing of the ventilator of the present invention; Figure 2 It is a schematic structural diagram of the internal support and adjustment assembly of the fan housing in the cross-sectional view state of the present invention; Figure 3 is a schematic diagram of the position of the mounting base on the housing of the ventilator of the present invention; Figure 4 It is a structural schematic diagram of the support rod at the air inlet on the fan casing of the present invention.

[0020] The reference numerals in the accompanying drawings are: 1- fan casing; 2- mounting base; 3- air inlet; 4- support assembly; 5- support rod; 6- air inlet box side panel; 7- casing side panel. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the implementation of the present invention clearer, the technical solution in the embodiment of the present invention will be described in more detail below in conjunction with the drawings in the embodiment of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions; the described embodiments are part of the embodiments of the present invention, not all of the embodiments; the embodiments described below with reference to the drawings and directional terms are exemplary and are intended to be used to explain the present invention, and cannot be understood as limitations on the present invention; based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The parts and equipment all adopt conventional models in the prior art, and the circuit connections adopt conventional connection methods in the prior art, which will not be described in detail here. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field. The embodiments of the present invention are described in detail below in conjunction with the drawings: like Figure 1-Figure 4As shown, a method for determining the distribution position of the fan casing support rod using finite element analysis includes: step 1: constructing a three-dimensional model of the fan casing according to customer needs, importing the fan performance parameters in the fan selection report into the finite element analysis software, and establishing a finite element simulation model of the fan casing 1 through the finite element analysis software; Step 2: Perform a simulation test on the structural strength of the fan casing 1 by applying boundary conditions to the finite element simulation model; Step 3: Install the support rod 5 at the position of the fan casing 1 with the largest deformation in the simulation test.

[0022] The three-dimensional model generated by the design software is saved as a file in step format, and then the geometry is cleaned up and the components are combined in the finite element pre-processing software. The mid-surface of the sorted geometry is extracted and then the shell mesh is divided. Compared with the solid mesh, the shell mesh can greatly reduce the number of units and nodes, thereby improving the calculation efficiency. The wind pressure load is applied to the inner surface of the fan casing 1, and the fan flanges need to be bound. The wind pressure and the binding share a node, which will cause algorithm errors and is time-consuming and laborious to handle. Therefore, the casing and the reinforcement are separated, and the casing is combined into a whole. The reinforcement is bound, and the high-order tetrahedral solid mesh is divided in this way.

[0023] like Figure 1-Figure 4 As shown, in step two, the boundary conditions are used to constrain the movement and rotation of the fan casing 1 in the process of calculating the structural strength of the computer casing. The mounting base 2 located on the side of the fan casing 1 is the constraint point of the boundary conditions, which constrains the three degrees of freedom of movement of the four mounting bases 2 of the fan.

[0024] The simulation test in step 2 includes: simulating the response of the fan casing 1 under the wind pressure load and gravity load during operation by finite element analysis software; and automatically calculating the stress and deformation of the fan casing 1 according to the given wind pressure.

[0025] In step one, the fan performance parameters in the fan selection report include the fan's inlet static pressure, outlet static pressure, outlet total pressure, and material performance parameters.

[0026] When creating a finite element simulation model using finite element analysis software in step one, it also includes welding connections between various welded components, binding connections of mounting surfaces, equivalent mass points of air dampers and bellows, displacement constraints of mounting base 2, application of wind pressure loads on the inner surface of the fan, and assignment of material performance parameters.

[0027] In step three, the deformation in the simulation test is the plate deformation of the fan casing 1, and the deformation at the air inlet 3 of the fan casing 1 is the largest. By calculating the casing under wind pressure and gravity load, the stress on the casing as a whole is far less than the yield limit of the material. However, the local deformation of the fan casing 1 has exceeded the plate thickness. In order to prevent the fan failure and damage caused by large deformation, the maximum deformation of the fan needs to be reduced. Therefore, the subsequent work only uses the deformation of the fan plate as the evaluation standard for the quality of the fan casing.

[0028] By checking the overall deformation of the fan casing 1, the displacement of the upper part of the air inlet is the largest, and the support rod 5 is arranged and installed at the position with the largest displacement. The reason for the large deformation of this area is that the casing side panel 7 where the air inlet 3 is located is subject to the static pressure from the inside of the fan and the negative pressure of the air inlet box. The two forces act in the same direction and are perpendicular to the casing side panel 7, so the deformation of this area is large. The main purpose of adding support rods 5 inside the fan casing 1 is to enhance the stability and durability of the structure. The support rods 5 can effectively prevent the deformation or distortion of the air inlet box due to factors such as wind pressure, mechanical vibration or temperature changes during operation, and maintain the overall shape and structural stability of the air inlet box. The provision of support rods 5 helps to reduce fatigue damage and structural deformation that may occur in the air inlet box during long-term operation, thereby extending the service life of the equipment. At the same time, a stable structure also contributes to the safety of maintenance personnel and the convenience of maintenance operations.

[0029] like Figure 1-Figure 4 As shown, a support and adjustment component for preventing deformation at the air inlet of a ventilator of the present invention comprises a support component 4 for preventing deformation of the air inlet, the support component 4 comprises: a support rod 5, an air inlet box side panel 6 and a casing side panel 7, the air inlet box side panel 6 is located on the outer side of the air inlet box, the casing side panel 7 is located between the volute and the air inlet box, both ends of the support rod 5 are fixedly connected between the air inlet box side panel 6 and the casing side panel 7, the casing side panel 7 and the air inlet box side panel 6 are casing structure components, which are pre-welded to the casing volute plate and the air inlet box volute plate, and the air inlet box side panel 7 is composed of two plates welded together.

[0030] There are two support rods 5, and the two support rods 5 are evenly arranged on the upper part of the air inlet. The support rod 5 is a cylindrical steel pipe, and the two support rods 5 are located in the same horizontal plane and parallel to each other.

[0031] The principle of the present invention is: 1. The present invention uses finite element analysis software to analyze and optimize the structure of the centrifugal fan in detail. On the premise of ensuring structural strength and stability, the plate is thinned to save steel plate material and improve material utilization; 2. The present invention conducts finite element analysis and calculation on the deformation of the casing side panel under wind pressure according to the characteristics of wind pressure distribution when the fan is working. Through analysis and calculation of different models, two support pipes are arranged at the deformation position of the casing side panel on the upper side of the air inlet to reduce the displacement of the casing side panel and enhance the safety and stability of the fan. The design of the support pipe should not only meet the requirements of structural stability, but also control the number to avoid too many support pipes from having a negative impact on the fan flow field; 3. The present invention verifies the optimized structure through finite element analysis method to ensure that it can maintain good anti-deformation ability and stability under various working conditions. The number of support pipes can be reduced as much as possible, saving manpower and material costs, and further improving the economy and practicality of the design.

[0032] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the distribution position of fan casing support rods using finite element analysis, characterized in that: The steps include: Step 1: construct a three-dimensional model of the fan casing according to customer requirements, import the fan performance parameters in the fan selection report into the finite element analysis software, and establish a finite element simulation model of the fan casing (1) through the finite element analysis software; Step 2: Performing a simulation test on the structural strength of the fan casing (1) by applying boundary conditions to the finite element simulation model; Step three: installing the support rod (5) at the position of the fan casing (1) with the largest deformation in the simulation test.

2. The method for determining the distribution position of the fan casing support rods by using finite element analysis according to claim 1, characterized in that: In step 2, the boundary condition is used to constrain the movement and rotation of the fan casing (1) during the process of calculating the structural strength of the casing, and the mounting base (2) located on the side of the fan casing (1) is the constraint point of the boundary condition.

3. The method for determining the distribution position of the fan casing support rods by using finite element analysis according to claim 1, characterized in that: The simulation test in step 2 includes: simulating the response of the fan casing (1) under wind pressure load and gravity load during operation by finite element analysis software; and automatically calculating the stress and deformation of the fan casing (1) according to a given wind pressure.

4. The method for determining the distribution position of the fan casing support rods by using finite element analysis according to claim 1, characterized in that: In the step 1, the fan performance parameters in the fan selection report include the fan's inlet static pressure, outlet static pressure, outlet total pressure and material performance parameters.

5. The method for determining the distribution position of the fan casing support rods by using finite element analysis according to claim 1, characterized in that: When the finite element simulation model is created using finite element analysis software in step 1, it also includes welding connections between various welding components, binding connections of the mounting surface, equivalent mass points of the damper and the bellows, displacement constraints of the mounting base (2), application of wind pressure loads on the inner surface of the ventilator, and assignment of material performance parameters.

6. The method for determining the distribution position of the fan casing support rods by using finite element analysis according to claim 1, characterized in that: In the step three, the deformation amount in the simulation test is the plate deformation amount of the fan casing (1), and the deformation amount at the air inlet (3) of the fan casing (1) is the largest.

7. The method for determining the distribution position of the fan casing support rods by using finite element analysis according to claim 6, characterized in that: By checking the overall deformation of the fan housing (1), it is found that the displacement of the upper portion of the air inlet is the largest, and the support rod (5) is arranged and installed at the position with the largest displacement.

8. A support and adjustment assembly for preventing deformation at the air inlet of a ventilator, characterized in that: The invention comprises a support assembly (4) for preventing deformation of the air inlet, wherein the support assembly (4) comprises: a support rod (5), an air inlet box side plate (6) and a casing side plate (7), wherein the air inlet box side plate (6) is located on the outer side of the air inlet box, and the casing side plate (7) is located between the volute and the air inlet box, and the two ends of the support rod (5) are fixedly connected between the air inlet box side plate (6) and the casing side plate (7).

9. The support and adjustment assembly for preventing deformation at the air inlet of a ventilator according to claim 8, characterized in that: There are a plurality of support rods (5), and the plurality of support rods (5) are evenly arranged on the upper part of the air inlet.

10. The support and adjustment assembly for preventing deformation at the air inlet of a ventilator according to claim 8, characterized in that: The support rod (5) is a cylindrical steel pipe.

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