Quick-closing butterfly valve design method based on numerical simulation

Abstract

The invention discloses a quick-closing butterfly valve design method based on numerical simulation, which comprises the following steps of: performing three-dimensional modeling, reasonable grid division and material parameter and boundary condition setting on a quick-closing butterfly valve by applying a finite element principle to obtain a numerical simulation result of a closing process of the quick-closing butterfly valve, and designing the quick-closing butterfly valve under different impact speeds, over-closing angles and collision impact areas. Different closing processes of the quick-closing butterfly valve are analyzed, stress changes in the closing processes are obtained, optimal parameters are obtained, theoretical guidance is provided for manufacturing of the quick-closing butterfly valve, and the cost and period caused by trial-manufacturing and testing in the manufacturing process of the quick-closing butterfly valve are greatly reduced. The method is intuitive, rapid and efficient.

Description

Technical Field

[0001] The present invention belongs to the field of valve design, and particularly relates to a design method of a quick-closing butterfly valve based on numerical simulation. Background Art

[0002] The main advantages of the quick-closing butterfly valve include strong sealing performance, simple structure, long service life, and convenient maintenance. It can improve production efficiency, reduce energy consumption and maintenance costs, and is therefore widely used in industries such as indoor energy, chemical and petrochemical, metallurgy, and water treatment. The safe operation of the quick-closing butterfly valve is related to the life and property safety of the people. Especially for the quick-closing butterfly valve under high-temperature and high-pressure conditions, once it fails and leaks, causing an explosion accident, it will cause a bad social impact. Therefore, it is of great significance to optimize the design of the quick-closing butterfly valve to ensure its normal operation. Summary of the Invention

[0003] To overcome the deficiencies of the prior art, the purpose of the present invention is to provide a design method of a quick-closing butterfly valve based on numerical simulation. By using the finite element principle, a three-dimensional model of the quick-closing butterfly valve is established, reasonable meshes are divided, material parameters and boundary conditions are set, the numerical simulation results of the closing process of the quick-closing butterfly valve are obtained, the different closing processes of the quick-closing butterfly valve under different impact speeds, over-closing angles, and collision impact areas are analyzed, the stress changes during the closing process are obtained, and the optimal parameters are obtained to provide theoretical guidance for the manufacture of the quick-closing butterfly valve. It has the advantages of being intuitive, fast, and efficient.

[0004] The present invention can be realized through the following technical solutions:

[0005] A design method of a quick-closing butterfly valve based on numerical simulation, the principle is: Step 1, use ANSYS software to establish a three-dimensional numerical model of the overall quick-closing butterfly valve, simplify the model, and select the components as the research object; use SolidWorks software to establish a three-dimensional model of the quick-closing butterfly valve; Step 2, perform mesh encryption on the impact contact surface between the butterfly valve and the valve seat; Step 3, set parameters; Step 4, time condition setting, the impact problem during the closing process of the quick-closing butterfly valve is a dynamic response problem of impact damage caused by the butterfly plate rotating 90° in a certain time to collide with the valve seat, and perform transient dynamics analysis; set the conditions during the transient dynamics analysis calculation of the quick-closing butterfly valve according to the design requirements; Step 5, through theoretical derivation, it is obtained that the important parameters affecting the impact on the quick-closing butterfly valve are impact parameters, which include: impact speed v, over-closing angle δ, and collision impact area A; and perform parameter optimization and comparative analysis; Step 6, through different parameter adjustments, obtain the optimal parameters of the quick-closing butterfly valve, so as to guide the design of the quick-closing butterfly valve.

[0006] Specifically, a design method of a quick-closing butterfly valve based on numerical simulation includes the following steps:

[0007] Step 1: Use ANSYS software to establish a three-dimensional numerical model of the fast-closing butterfly valve. First, simplify the model. Since the failure caused by the impact behavior of the fast-closing butterfly valve is mainly aimed at the impact object and the target object, other components far from the impact object and the target object can be ignored. Therefore, only four components, namely the valve body, valve stem, butterfly plate, and valve seat, are selected as the research objects. Use SolidWorks software to establish a three-dimensional model of the fast-closing butterfly valve. On the premise of not affecting the structural strength and calculation accuracy, in order to ensure the mesh quality and calculation speed, features such as chamfers and small fillets in the model are ignored;

[0008] Step 2: Mesh generation. In order to obtain impact strength data with sufficient accuracy in the collision and impact contact area, the impact contact surfaces of the butterfly valve and the valve seat are subjected to mesh refinement. The mesh size along the contact surface is 0.1 mm. Through mesh independence verification, it is finally determined that the mesh model has a total of 23,736 elements.

[0009] Step 3: Set parameters. The parameters refer to the materials of the valve body, valve stem, butterfly plate, and valve seat, as well as the impact speed, over-closing angle, and collision and impact area parameters of the fast-closing butterfly valve. In addition, in order to simulate the real working conditions of the collision and impact, both the valve body and the butterfly plate are set as elastic bodies;

[0010] Step 4: Time condition setting. The impact problem during the closing process of the fast-closing butterfly valve can be considered as a dynamic response problem of the butterfly plate rotating 90° in a certain time to collide with the valve seat, causing impact damage, and perform transient dynamics analysis. When performing transient dynamics analysis and calculation on the fast-closing butterfly valve according to the design requirements, the following conditions are set: Apply displacement constraints to the inlet and outlet ends of the valve body; Apply rotational displacement to the butterfly plate; Set friction contact on the contact surface between the butterfly plate and the valve seat of the valve body, and the friction coefficient is set to 0.15; Ignore rigid damping; Set the closing time to 0.5 s; Set the impact time to 0.1 s, then the total analysis time of the transient dynamics is 0.6 s; Set the load step to two steps. The first load step is set to 0 - 0.5 s, representing the fast-closing process and the impact instant, and set the load sub-step to 180 steps; The second load step is set to 0.5 - 0.6 s, representing the dynamic response process after the impact. In order to obtain an accurate impact stress change process, the load sub-step is set to 5000 steps;

[0011] Step 5: Impact effects of different structural parameters and impact parameters on the fast-closing butterfly valve. In this section, three parameters are selected for variable parameter comparative analysis. Impact parameters: Impact speed v (achieved by changing the fast-closing time), over-closing angle δ, collision and impact area A (achieved by changing the width of the sealing surface):

[0012] Step 6: Obtain the optimal parameters of the fast-closing butterfly valve through different parameter adjustments. Furthermore, guide the design of the fast-closing butterfly valve. The specific parameter adjustments are as follows:

[0013] The impact velocity of the fast-closing butterfly valve at the moment of fast closing depends on the length of the closing time. When the fixed over-closing angle is 0° and the width of the valve seat sealing surface is 5 mm, three different fast-closing time schemes of 0.3 s, 0.5 s, and 1 s are selected for comparative study;

[0014] The size of the impact area depends on the width of the butterfly plate and the valve seat sealing surface. When the fixed over-closing angle is 0° and the fast-closing time is 0.5 s, three different valve seat sealing surface width schemes of 3 mm, 5 mm, and 7 mm are selected for comparative study;

[0015] The impact characteristics of different over-closing angles are different, which will directly affect the fast-closing performance of the butterfly valve. When the fixed fast-closing time is 0.5 s and the width of the valve seat sealing surface is 5 mm, the impact characteristics of three over-closing angles (β = 0°, 0.10°, 0.15°) within the closing time of 0.5 s are analyzed.

[0016] Advantages of the present invention:

[0017] 1) The present invention can accurately simulate the closing process of the fast-closing butterfly valve; 2) The present invention can efficiently obtain the influence of the parameters of the fast-closing butterfly valve on its performance; 3) By adjusting different parameters, it can provide theoretical guidance for the design of the fast-closing butterfly valve, and greatly reduce the cost and cycle brought by trial production and testing during the manufacturing process of the fast-closing butterfly valve. Description of the drawings

[0018] Figure 1 is the finite element model of the fast-closing butterfly valve;

[0019] Figure 2 is the mesh division in step two; (a) front view, (b) side view;

[0020] Figure 3 is the stress nephogram at different moments during the fast-closing process obtained by numerical simulation calculation in Example 1;

[0021] Figure 4 is the maximum impact stress nephogram of the valve corresponding to different fast-closing times obtained by numerical simulation calculation in Example 1;

[0022] Figure 5 is the time history curve of the contact pressure at different closing speeds in Example 1;

[0023] Figure 6 is the maximum impact equivalent stress distribution nephogram at different sealing surface widths in Example 1;

[0024] Figure 7 is the time history curve of the overall maximum equivalent stress at different sealing surface widths in Example 1;

[0025] Figure 8It is the contour map of the maximum impact stress distribution at different over-closure angles in Embodiment 1;

[0026] Figure 9 It is the time history curve of the impact stress at different over-closure angles in Embodiment 1. Specific Embodiment

[0027] In order to make the objectives and technical solutions of the present invention clearer and easier to understand, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] Embodiment 1

[0029] The applicable environmental parameters of the quick-closing butterfly valve designed in this embodiment are shown in Table 1, and the specific design process is as follows:

[0030] Table 1 Applicable environmental parameters of the quick-closing butterfly valve

[0031]

[0032]

[0033] Step 1: Use ANSYS software to establish a three-dimensional numerical model of the quick-closing butterfly valve. First, simplify the model. Since the failure caused by the impact behavior of the quick-closing butterfly valve is mainly for the impact object and the target object, other components far from the impact object and the target object can be ignored. Therefore, only four components, namely the valve body, valve stem, butterfly plate, and valve seat, are selected as the research objects. Use SolidWorks software to establish a three-dimensional model of the quick-closing butterfly valve (see Figure 1 shown). On the premise of not affecting the structural strength and calculation accuracy, in order to ensure the mesh quality and calculation speed, features such as chamfers and small fillets in the model are ignored;

[0034] Step 2: Perform mesh division. In order to obtain impact strength data with sufficient accuracy in the collision impact contact area, the impact contact surfaces of the butterfly valve and the valve seat are subjected to mesh encryption treatment. The mesh size along the contact surface is 0.1 mm. Through mesh independence verification, it is finally determined that the mesh model has a total of 23,736 elements, see Figure 2 shown.

[0035] Step 3: Set parameters as shown in Table 2. The parameters refer to determining the materials of the valve body, valve stem, butterfly plate, and valve seat according to the specific working pressure, working temperature, and medium of the quick-closing butterfly valve, as well as the impact speed, over-closure angle, and collision impact area parameters of the quick-closing butterfly valve. In addition, in order to simulate the real working conditions of the collision impact, both the valve body and the butterfly plate are set as elastic bodies;

[0036] Table 2 Material property parameters

[0037] Parameter / Component Valve body, valve cover, disc Valve stem Material A351 CF8 20Cr13 Elastic modulus (GPa) 210 193 <![CDATA[Tensile strength σ b (MPa)]]> 485 520 Poisson's ratio ν 0.29 0.32 <![CDATA[Yield strength σ s (MPa)]]> 205 245

[0038] Step 4: Set time conditions, apply displacement constraints to the inlet and outlet ends of the valve body; apply rotational displacement to the butterfly plate; set frictional contact at the contact surface between the butterfly plate and the valve seat of the valve body, and set the friction coefficient to 0.15; ignore rigid damping; set the closing time to 0.5 s; set the impact time to 0.1 s, then the total analysis time of transient dynamics is 0.6 s; set the load step to two steps, the first load step is set to 0 - 0.5 s, representing the fast closing process and the impact instant, and set the load sub-step to 180 steps; the second load step is set to 0.5 - 0.6 s, representing the dynamic response process after the impact. To obtain the accurate impact stress change process, set the load sub-step to 5000 steps.

[0039] Step 5: Analyze the impact on the fast - closing butterfly valve with different structural parameters and impact parameters. Select three parameters, namely the impact velocity v, the over - closing angle δ, and the collision impact area A, for variable parameter comparative analysis. The butterfly plate and the valve stem are connected by a pin. When the fast - closing butterfly valve works, the actuator drives the valve stem and the butterfly plate to rotate together to achieve the fast - closing process. When the butterfly plate rotates from fully open to fully closed, the valve closes with a uniform angular acceleration. After a time t, the valve is completely closed. It can be seen that when the valve closes with a uniform angular acceleration, there is an inertial force acting on it. Therefore, the angular acceleration when the fast - closing butterfly valve closes should be calculated first:

[0040]

[0041] ω = ω 0 +βt (2)

[0042] v = ωr (3)

[0043] s = rΔθ (4)

[0044] In formulas (1) - (4): θθ 0 is the initial angular displacement, θ is the final angular displacement, ωω 0 is the initial angular velocity, ω is the final angular velocity, t is the closing time, and β is the angular acceleration. v is the velocity in the tangential direction; r is the radius of the butterfly plate; s is the tangential displacement of the butterfly plate.

[0045] Next, conduct a theoretical analysis of the impact process of the rotary - type fast - closing butterfly valve. In the automatic control system, for the rotating components of the valve, the torque generated by the moment of inertia of the butterfly plate needs to be considered. By establishing a calculation model similar to the shape of the sealing surface of the butterfly plate, conduct a study on the moment of momentum of the rotational motion.

[0046] According to the theorem of moment of momentum:

[0047] J(w - w 0 ) = TΔt (5)

[0048] Since the shape of the butterfly disc of a triple-eccentric butterfly valve is neither a regular circular plate nor a regular elliptical plate, the accurate calculation of its moment of inertia is very complex. To simplify the calculation, it can be approximately replaced by the moment of inertia of an elliptical cylinder. The formula for calculating the moment of inertia of an elliptical cylinder is as follows:

[0049]

[0050] Where m is the mass of the elliptical cylinder, a is the length of the axis perpendicular to the rotation axis, and l is the thickness of the ellipse.

[0051] According to the theorem of moment of momentum

[0052] T = Fr (7)

[0053] In equations (5)-(7): J is the moment of inertia of the butterfly disc and its rotating components, which is related to the mass of the butterfly disc with different shapes; w is the angular velocity of the butterfly disc movement; T is the torque; F is the impact force; r is equivalent to the force arm, that is, the distance between the center axis and the valve seat sealing surface; Δt is the time difference when the speed decreases from the spindle rotation speed to zero, which is related to the valve seat material. Combining equations (1)-(7) gives the rotational impact force:

[0054]

[0055] At the moment when the fast-closing butterfly valve closes, the butterfly disc impacts the valve seat sealing surface, and the impact force acts not only on the valve seat sealing surface but also on the butterfly disc sealing surface. In this embodiment, the force analysis is carried out at the maximum cone angle of the butterfly disc sealing conical surface at the impact moment. The tangential reaction force F is received by the inclined conical surface of the butterfly disc, and the impact component force F 1 in the normal direction of the inclined conical surface has the greatest impact on the structural strength, and the horizontal impact component force T with less impact on the structure is ignored. Assuming that the triple-eccentric cone angle is θ, then the normal impact force:

[0056] F 1 = Ftanθ (9)

[0057] The average impact stress σ received by the entire conical surface per unit area is:

[0058]

[0059] In the formula, S is the toroidal area of the butterfly disc sealing conical surface, that is, a part of the conical surface intercepted vertically.

[0060] Use the formula to qualitatively analyze the relevant parameters of the impact influence stress. Among them, the toroidal area S is directly related to the curved surface equation of the outer surface of the butterfly disc, and the main geometric parameter is the cone angle θ, while the normal impact force F 1 depends on the total rotational impact force F and the cone angle θ, and the impact force F is also associated with the moment of inertia J of the butterfly disc, the impact angular velocity ω of the butterfly disc, the impact action time Δt, and the distance r between the valve stem and the butterfly disc sealing surface.

[0061] Based on the above analysis, it can be seen that when designing the valve, the impact velocity v, the over-closure angle δ, and the collision impact area A are important influencing parameters.

[0062] Step 6: Obtain the optimal parameters according to the simulation calculation results, where Figure 3 is the stress nephogram at different moments during the quick closing process. It can be seen from the figure that the peak stress of the butterfly valve is much greater than that of the base. The instantaneous stress of the butterfly valve is small at the beginning of closing, and it increases to 31.073 MPa at the instant of closing at 0.5 s; the stress at 0.6 s is 2.1 MPa, and the stress values at each moment are less than the allowable stress of the material, meeting the strength requirements.

[0063] By performing transient dynamic analysis on the quick-closing butterfly valve under different quick-closing time (0.3 s, 0.5 s, 1 s) conditions, the impact velocities under different quick-closing time conditions are obtained. Figure 4 is the maximum impact stress nephogram of the valve corresponding to different quick-closing times. It can be seen from the figure that the maximum impact stress corresponding to the quick-closing time of 0.3 s is 132.45 MPa, and the area where the stress value is greater than 30.0 MPa is almost distributed on the entire butterfly plate and valve seat. It can be seen that the impact influence area is very large. When closing within 0.5 s, the impact influence area is slightly smaller than that at 0.3 s. When closing within 1 s, the influence area is mainly concentrated on the sealing contact surface between the valve seat and the butterfly plate and a small part of the discontinuous parts of the butterfly plate structure. It can be seen that as the closing time shortens, the impact velocity of the butterfly plate hitting the valve seat transiently is greater, and the impact influence area is larger.

[0064] Figure 5 is the time history curve of the contact pressure under different closing speeds, where (a), (b), and (c) correspond to the quick-closing times of 0.3 s, 0.5 s, and 1 s respectively. For the condition with a quick-closing time of 0.3 s, the contact pressure increases sharply to the peak value of 56.487 MPa at the instant of closing, and then the contact pressure shows irregular oscillations and gradually decays to a stable value within 0.3 - 0.4 s, not exceeding the allowable specific pressure of the material. The change laws of the contact pressure in the remaining conditions (0.5 s, 1.0 s) are similar, and the maximum impact contact pressures are 34.365 MPa and 11.597 MPa respectively. There is no over-closure angle in all three conditions, and the final contact pressure cannot maintain the seal of the structure.

[0065] The shorter the quick-closing time, the greater the speed of the butterfly plate hitting the valve seat sealing surface at the instant of quick closing, and the greater the instantaneous peak contact pressure on the sealing surface, but there is no necessary connection with the sealing performance of the structure.

[0066] To study the influence degree of different impact areas on the impact behavior of the quick-closing butterfly valve, in this embodiment, 4 different impact seal surface widths of 1 mm, 3 mm, 5 mm, and 7 mm are selected for comparative study.

[0067] Figure 6 It is the contour map of the maximum impact equivalent stress under different sealing surface widths. It can be seen from the figure that the high stress areas all appear at the bevel angle of the butterfly plate sealing conical surface. There is a large stress concentration phenomenon on the butterfly plate corresponding to the impact area with a sealing surface width of 1 mm, that is, the safety margin of the butterfly valve is the smallest.

[0068] Figure 7 It is the time history curve of the overall maximum equivalent stress under different sealing surface widths. (a), (b), and (c) correspond to widths of 3 mm, 5 mm, and 7 mm respectively. It can be seen from the figure that when the sealing surface width is 1 mm, the stress increases sharply to the peak value of 116.61 MPa at the moment of closing, that is, at 0.5 s, and then the stress oscillates irregularly and gradually decays to a stable value within the time range of 0.5 - 0.6 s. The maximum impact stress meets the allowable stress of the material; when the sealing surface width is 3 mm, the stress increases sharply to the peak value of 108.78 MPa at the moment of closing, and then the stress decays and oscillates to stability within the time range of 0.5 - 0.6 s. The maximum impact stress is less than the allowable stress of the material; when the sealing surface width is 7 mm, the stress increases to the peak value of 103.32 MPa at the moment of closing, and then the stress decays and oscillates to stability within the time range of 0.5 - 0.6 s. The maximum impact stress is less than the allowable stress of the material. It can be seen that with the increase of the sealing surface width, the impact area increases and the maximum impact stress decreases. The structures of all three working conditions meet the strength requirements.

[0069] Analyze the impact characteristics at different over - closing angles (δ = 0°, 0.10°, 0.15°) within the closing time of 0.5 s.

[0070] Figure 8 It is the contour map of the maximum impact stress under different over - closing angles. Taking the closing angle of 90.10° as an example, the maximum impact stress is 313.78 MPa, which is greater than the allowable stress value of the material, and the area where the stress value is greater than 50.0 MPa is mainly concentrated in the discontinuous part of the butterfly plate structure; when the closing angle is 90.15°, the maximum impact stress is 438.69 MPa, which is greater than the allowable stress value of the material, and the area where the stress value is greater than 50.0 MPa increases compared with 90.05°; it can be seen that with the increase of the over - closing angle, the impact influence area of the butterfly plate transiently hitting the valve seat is larger. Among them, the impact stress concentration phenomenon of the butterfly valve corresponding to 90.15° (i.e., over - closing 0.15°) is the most serious. The larger impact stress is distributed on the impact surface, that is, the sealing contact ring surface and the corner part of the butterfly plate; the impact stress distribution of the 90° butterfly valve is the most uniform, and the range of the high - stress area is small. Therefore, the precise positioning of the fast - closing angle of the butterfly valve is very important. Once the over - closing angle is too large, it may cause damage to the butterfly plate and the valve body.

[0071] Figure 9The following are the time-history curves of impact stress under different over-closing angles, where (a), (b), and (c) correspond to over-closing angles of 0°, 0.10°, and 0.15°, respectively. When the closing angle is over 0.10°, the impact stress increases sharply to a peak value of 313.78MPa at the moment of closing, i.e., 0.5s, and then the stress shows irregular oscillations and gradually decays to a stable value within 0.5-0.6s. The maximum impact stress exceeds the allowable stress of the material. When the closing angle is over 0.15°, the stress increases sharply to a peak value of 271.57MPa at the moment of closing, i.e., 0.5s, and then the stress shows irregular oscillations and gradually decays to a stable value within 0.5-0.6s. The maximum impact stress is 475.96MPa, which exceeds the allowable stress of the material.

[0072] As the over-closing angle increases, the impact stress peak value (108.78MPa, 313.78MPa, 475.16MPa) increases, and the impact stress finally stabilizes (about 1.0MPa, 300MPa, 400MPa). The impact stress oscillation corresponding to the normal 90° closure is the largest, but the amplitude is the smallest. From the perspective of the dynamic response of the impact stress, the larger the over-closing angle, the more unfavorable it is to the structure, but a too small over-closing angle will also cause the peak contact pressure of the sealing surface to be too small, causing the seal to fail.

[0073] Therefore, after comprehensive consideration, the optimal design parameters for the fast closing butterfly valve under this working condition are an over-closing angle of 0.10°, a sealing surface width of 7mm, and an over-closing time of 1s. This is because the slower the speed, the larger the area, and the less stress the structure bears, and an over-closing angle of 0.1° can ensure that the sealing performance after stabilization meets the requirements.

[0074] It should be noted that the above examples 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 aforementioned embodiments, it should be understood by those skilled in the art that they can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein by equivalents. These modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A design method for a fast-closing butterfly valve based on numerical simulation, characterized in that: The finite element principle is used to perform three-dimensional modeling of the fast-closing butterfly valve, divide the grid reasonably, set material parameters and boundary conditions, and obtain the numerical simulation results of the closing process of the fast-closing butterfly valve. The different closing processes of the fast-closing butterfly valve under different impact speeds, closing angles, and collision impact areas are analyzed to obtain the stress changes during the closing process, obtain the optimal parameters, and provide theoretical guidance for the manufacturing of fast-closing butterfly valves.

2. A method for designing a fast-closing butterfly valve based on numerical simulation according to claim 1, characterized in that: The following steps are involved: Step 1: Use ANSYS software to establish a three-dimensional numerical model of the fast-closing butterfly valve as a whole, simplify the model, and select the components as the research object; use SolidWorks software to establish a three-dimensional model of the fast-closing butterfly valve; Step 2: Mesh division. In order to obtain impact strength data with sufficient accuracy in the collision impact contact area, mesh encryption is performed on the impact contact surface between the butterfly valve and the valve seat. Step 3, setting parameters; the parameters refer to the parameters including but not limited to the materials of the valve body, valve stem, butterfly plate and valve seat, as well as the impact speed v, over-closing angle δ, and collision impact area A of the fast-closing butterfly valve according to the working pressure P, working temperature T, and medium of the fast-closing butterfly valve; in addition, in order to simulate the real working conditions of the collision impact, the valve body and butterfly plate are set to be elastic; Step 4: Time condition setting. The impact problem of the closing process of the fast-closing butterfly valve is the dynamic response problem of the impact damage caused by the butterfly plate rotating 90° and colliding with the valve seat in a certain time t. Transient dynamic analysis is performed; the conditions for transient dynamic analysis calculation of the fast-closing butterfly valve are set according to the design requirements; Step 5: Through theoretical derivation, it is concluded that the important parameter affecting the impact of the fast closing butterfly valve is the impact parameter, and a comparative analysis of parameter optimization is performed; Step 6. By adjusting different parameters, the optimal parameters of the quick-closing butterfly valve are obtained to guide the design of the quick-closing butterfly valve.

3. The method for designing a fast-closing butterfly valve based on numerical simulation according to claim 2 is characterized in that: In step one, the model is simplified to minimize the calculation time and save calculation costs without affecting the calculation accuracy; only four components, namely the valve body, valve stem, butterfly plate and valve seat, are selected as research objects, and the features of chamfers and small fillets in the model are ignored.

4. The method for designing a fast-closing butterfly valve based on numerical simulation according to claim 2 is characterized in that: The impact parameters in step five are the impact speed v of the fast-closing butterfly valve, the over-closing angle δ, and the collision impact area A.

5. The method for designing a fast-closing butterfly valve based on numerical simulation according to claim 2 is characterized in that: In step five, the impact velocity v is achieved by changing the fast closing time t, and the collision impact area A is achieved by changing the sealing surface width.

6. The method for designing a fast-closing butterfly valve based on numerical simulation according to claim 4 is characterized in that: In step five, the impact velocity v, over-closing angle δ, and collision impact area A on the sealing performance are analyzed as follows: (1) The collision impact velocity of the fast-closing butterfly valve at the moment of fast closing depends on the length of the closing time t. The over-closing angle is fixed at 0°, the collision impact area is 5 mm, and three different fast-closing time schemes of 0.3s, 0.5s and 1s are selected for comparative study; (2) The fast-closing time is fixed at 0.5s, the over-closing angle is 0°, and three different impact area schemes of 3mm, 5mm and 7mm are selected for comparative study; (3) The fast-closing time is fixed at 0.5s, the collision impact area is 5, and the impact characteristics within the closing time of 0.5s are analyzed when the over-closing angle δ = 0°, 0.10°, and 0.15°.

7. The method for designing a fast-closing butterfly valve based on numerical simulation according to claim 2 is characterized in that: In step 4, the following conditions are set for the transient dynamic analysis calculation of the fast-closing butterfly valve: apply displacement constraints to the inlet and outlet ends of the valve body; apply rotational displacement to the butterfly plate; set friction contact between the contact surface of the butterfly plate and the valve seat of the valve body, and the friction coefficient is set to 0.15; ignore rigid damping; set the closing time to 0.5s; set the impact time to 0.1s, and the total transient dynamic analysis time to 0.6s; set the load step to two steps: The first load step is set to 0-0.5s, representing the fast closing process and the impact moment, and the load substep is set to 180 steps; The second load step is set to 0.5-0.6s, representing the dynamic response process after impact. In order to obtain the accurate impact stress change process, the load sub-step is set to 5000 steps; Afterwards, the impact response of the fast-closing butterfly valve under different impact velocities was studied. The load and boundary condition settings only changed the fast-closing time to 0.3s and 1s, and the other settings remained unchanged.

8. The method for designing a fast-closing butterfly valve based on numerical simulation according to claim 2 is characterized in that: In step six, the parameter adjustment process is as follows: (1) The collision impact speed of the fast-closing butterfly valve at the moment of fast closing depends on the length of the closing time. Three different fast-closing time schemes of 0.3s, 0.5s and 1s are selected for comparative study; (2) In order to study the influence of different impact areas on the impact behavior of the fast-closing butterfly valve, 4 different impact area schemes of 1mm, 3mm, 5mm and 7mm are selected for comparative study; (3) Different over-closing angles have different impact characteristics, which will directly affect the fast-closing performance of the butterfly valve; analyze the impact characteristics of three over-closing angles δ = 0°, 0.10°, 0.15° within a closing time of 0.5s; The optimal design parameters are an over-closing angle of 0.10°, a sealing surface width of 7mm, and an over-closing time of 1s; this is because the slower the speed, the larger the area, and the less stress the structure bears, and an over-closing angle of 0.1° can ensure that the sealing meets the requirements after stabilization.

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