Design method of porous throttling sleeve of steam regulating valve with multi-stage pressure drop structure

Abstract

The invention discloses a method for designing a porous throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure. The method comprises the steps that the type, working condition parameters and geometric parameters of a valve needing to be designed are obtained; the blocking pressure difference of the regulating valve is calculated, and the minimum pressure reduction stage number where choking flow does not occur is calculated according to the pressure distribution of the indexes; the throttling area needed by each stage when the pressure drop requirement is met is determined through a computational fluid mechanics method; the noise level of the regulating valve under different apertures is determined by adopting a computational fluid mechanics method, and the aperture corresponding to the minimum noise is found through a curve equation fitting method. The method is applied to the design process of the porous throttling sleeve of the steam regulating valve, the optimal stage number is determined by calculating the minimum pressure reduction stage number, the flow area of each stage and the pore diameter with the lowest noise level, the structural design of the porous sleeve of the steam regulating valve is achieved, and the method is particularly suitable for industrial scenes with high steam parameter control precision and strict noise requirements; and the method has remarkable technical value and market application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of special valve structure design, and particularly relates to a design method of a porous throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure. BACKGROUND

[0002] In the industrial field, as the core component of the steam system pressure and flow control, the running stability, noise level and service life of the steam regulating valve directly affect the safety and energy efficiency of the entire system. At present, the existing steam regulating valve pressure reduction structure design has obvious limitations. On the one hand, some designs rely on experience to determine the number of multi-stage pressure reduction, and fail to combine the blocked flow pressure difference and pressure distribution law for quantitative calculation, which easily leads to high single-stage pressure drop, causing damage to the valve core and throttling components, and shortening the service life of the equipment. On the other hand, the design of the hole diameter of the throttling sleeve often lacks a systematic noise optimization logic, making it difficult to accurately control the operating noise, especially under high pressure difference conditions, the noise level is high, which affects the production environment and personnel health (such as patent CN110185842B discloses a multi-stage pressure reduction sleeve structure parameter optimization method of a high pressure difference regulating valve). At the same time, the existing multi-stage throttling structure also has the problems of complex design process, separate calculation and processing of the hole diameters of each stage, which not only prolongs the design cycle, but also increases the processing cost and assembly difficulty. Therefore, it is urgent to propose a design method of a porous throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure, which has practical engineering application value. SUMMARY

[0003] The present application aims to overcome the defects in the prior art and provide a design method of a porous throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure. The present application proposes a calculation method for the number of stages, throttling area and hole diameter of the porous throttling sleeve of the steam regulating valve, and proposes a complete technical process to obtain the parameters of the porous throttling sleeve of the steam regulating valve with the best noise reduction performance.

[0004] To achieve the above-mentioned purpose, the specific technical solutions adopted by the present application are as follows: A design method of a porous throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure, the specific steps are as follows: S1: obtaining the valve type, working condition parameters and geometric parameters of the steam regulating valve; S2: calculating the blockage pressure difference of the target steam regulating valve according to the set pressure distribution, obtaining the minimum pressure reduction stage required by the target steam regulating valve under the given working condition; S3: according to the pressure distribution obtained in S2, using the computational fluid dynamics method to iterate the throttle area of each stage; S4: determining the recommended value of the aperture according to the aperture of the regulating valve, selecting a suitable aperture near the recommended value, calculating the number of throttle holes of each stage according to the throttle area of each stage obtained in S3 and arranging them, using the computational fluid dynamics method to obtain the noise level of the steam regulating valve corresponding to different apertures, using function fitting to obtain the aperture of the throttle hole corresponding to the lowest noise level, and rounding to obtain the best throttle hole aperture; S5: on the basis of the minimum pressure drop stage determined in S2, repeating the steps of S2-S4 by increasing different number of pressure drop stages, obtaining the pressure drop stage with the lowest noise level under different pressure drop stages, and taking the structure with the best noise control ability with the pressure drop stage as the final design structure.

[0005] Preferably, in step S1, the working condition parameters include the inlet temperature of the steam regulating valve , the inlet steam pressure , the outlet steam pressure , the required mass flow , and the geometric parameters include the valve aperture of the steam regulating valve .

[0006] Preferably, in step S2, the expression of the blockage pressure difference of the steam regulating valve is as follows:

[0007] wherein is the inlet steam pressure, is the specific heat ratio coefficient of the steam, is the pressure difference ratio coefficient of the control valve under the blockage flow condition; when the size of the control valve and the accessory connecting pipe is consistent, the is simplified as , wherein is the pressure difference ratio coefficient of the control valve without accessory connecting pipe under the blockage flow condition, which is determined by the valve type of the regulating valve; the is based on the air fluid with atmospheric pressure close to 1.40, and if the specific heat ratio of the fluid is not 1.40, the specific heat ratio coefficient is used as the coefficient for adjustment; the calculation expression of the specific heat ratio coefficient is as follows:

[0008] wherein is the specific heat ratio of the steam.

[0009] Preferably, in step S2, the pressure distribution adopts a geometrically decreasing distribution, i.e.

[0010] Right now ; Initial value of decompression stage Set to 1, calculate the pressure difference at each level based on the pressure distribution, if a certain level of pressure difference... Greater than the blocking pressure difference Then the decompression stage will be at the initial value. Add 1 to the previous step, calculate the pressure difference for each stage, and repeat this step until the pressure difference for each stage is less than the blocking pressure difference for the first time. Record the number of pressure-reducing stages of the control valve obtained at this point as . .

[0011] As a preferred embodiment, the throttling area iteration method in step S3 is as follows: Setting the first The initial throttling area of ​​the multi-hole throttling sleeve is [value missing]. , The expression is as follows:

[0012] in The pressure reduction stage in which the porous throttling sleeve is located. The valve diameter of the steam regulating valve. Through the above inlet pressure Export pressure Based on the characteristics of the pressure difference distribution at each level, the first... The pressures before and after the multi-stage porous throttling sleeve are respectively , By inputting this as a boundary condition into computational fluid dynamics software, the first boundary condition can be calculated. Multi-stage porous throttling sleeve with a throttling area of The mass flow rate at that time is According to the law of conservation of mass, if the mass flow rate of the steam regulating valve is... Then the mass flow rate of each pressure-reducing structure is also ,like Then it is believed Can be used as the first The final throttling area of ​​the multi-hole throttling sleeve Otherwise if Then set ,Will The throttling area is used for computational fluid dynamics calculations in the next iteration to obtain the corresponding mass flow rate. Otherwise if Then set , the CFD calculation is performed as the throttle area of the next iteration, and the mass flow corresponding to the next iteration is obtained .

[0013] As preferred, the boundary condition setting method of the computational fluid dynamics in step S3 is as follows: The fluid inlet is set as a pressure inlet, the fluid outlet is set as a pressure outlet, the inlet temperature is the steam medium temperature, and the outlet temperature is consistent with the inlet temperature.

[0014] As preferred, the throttle hole diameter in step S4 is The recommended value is as follows: if , the throttle hole diameter is 3mm; if , the throttle hole diameter is 5mm; if , the throttle hole diameter is 10mm; the appropriate hole diameter selection interval is , and the number of different hole diameters selected is 7, wherein the recommended hole diameter must be included.

[0015] As preferred, the number of throttle holes in step S4 is The following inequality must be satisfied: ; Wherein represents the number of throttle holes of the th stage, and the throttle hole mode must satisfy that the number of rows of throttle holes is even, if the number of holes is odd, one throttle hole is added on the basis of the calculated number of holes, and the vertical distance between the centers of the adjacent two rows of throttle holes is to ensure the continuity of flow regulation.

[0016] As preferred, the boundary condition of the computational fluid dynamics in step S4 is that the inlet pressure is , the outlet pressure is , and the noise calculation is repeated 7 times to obtain the corresponding noise value under each hole diameter; the function is a polynomial function, and a cubic function is preferentially selected as the function type, and the domain of the function is ; the rounded throttle hole diameter should not be less than the throttle hole diameter corresponding to the minimum value of the function, and the rounded throttle hole diameter should be an integer multiple of 0.1mm.

[0017] As preferred, the number of different pressure drop stages in step S5 is increased by one, two and three respectively, and the steam regulating valve structure after increasing the number of pressure drop stages is operated by S2-S4.

[0018] Compared with the prior art, the present application has the following beneficial effects: The application proposes a design method for the throttling sleeve of a steam regulating valve with multi-stage pressure drop. Only by obtaining the actual working condition parameters, geometric parameters and regulating valve type, the required minimum pressure reduction stages, throttling area of each stage, hole diameter, number of holes and arrangement of the throttling holes of the regulating valve can be calculated step by step. The calculation logic is clear and easy to understand, the parameter determination logic is rigorous, and the accuracy of the design results is ensured by combining numerical simulation calculation, ensuring the rapidity and accuracy of the multi-stage pressure drop structure design. It is especially suitable for industrial scenes with high steam parameter control accuracy and strict noise requirements, and has significant technical value and market application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural section view of a certain steam regulating valve; Figure 2 is a flowchart of step S2; Figure 3 is a flowchart of step S3; Figure 4 is a flowchart of step S4; In the figure: 1, regulating valve body; 2, regulating valve plug; 3, first-stage pressure reduction sleeve; 4, second-stage pressure reduction sleeve; 5, regulating valve seat. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application will be described in detail below with reference to the drawings. The following specific calculation formula is only one of the ways disclosed in the application. All optimization schemes implemented based on the application without producing innovative results fall within the protection scope of the application.

[0021] The application will be further described and explained below in combination with the drawings and specific embodiments.

[0022] In order to better illustrate the design method of the application, first, the structure and working principle of a certain steam regulating valve are briefly described. As shown in Figure 1 , the steam regulating valve structure mainly includes a regulating valve body 1, a regulating valve plug 2, a first-stage pressure reduction sleeve 3, a second-stage pressure reduction sleeve 4 and a regulating valve seat 5. The steam medium enters the regulating valve body 1 from the regulating valve inlet, is reduced in pressure by the first-stage pressure reduction sleeve 3, contacts the second-stage pressure reduction sleeve 4 for the second time to be reduced in pressure, and then flows into the downstream pipeline system from the regulating valve outlet.

[0023] Based on the above-mentioned steam regulating valve structure, in a preferred implementation manner of the application, the above-mentioned design method for the multi-hole throttling sleeve of the steam regulating valve with multi-stage pressure drop structure includes the following S1-S5 steps, and the specific implementation process will be described below.

[0024] S1: Obtain the valve type, working condition parameters and geometric parameters of the steam regulating valve.

[0025] As a preferred embodiment of the present application, the working condition parameters obtained in this step include the steam regulating valve inlet temperature , inlet steam pressure , outlet steam pressure , required mass flow , and the geometric parameters include the steam regulating valve port diameter .

[0026] S2: Calculate the blockage pressure difference of the target steam regulating valve according to the set pressure distribution, and obtain the minimum pressure reduction stage required by the target steam regulating valve under the given working condition, the process of which is shown in Figure 2 .

[0027] As a preferred embodiment of the present application, in this step, the expression of the blockage pressure difference of the steam regulating valve is as follows: ; wherein is the inlet steam pressure, is the specific heat ratio coefficient of steam, is the pressure difference ratio coefficient of the control valve with attached pipe fittings under the blockage flow condition; When the sizes of the control valve and the attached pipe fittings are consistent, the is simplified as , wherein is the pressure difference ratio coefficient of the control valve without attached pipe fittings under the blockage flow condition, which is determined by the valve type of the regulating valve; The is based on the air fluid with an atmospheric pressure close to 1.40, and if the specific heat ratio of the fluid is not 1.40, the specific heat ratio coefficient is used as the coefficient for adjustment; The calculation expression of the specific heat ratio coefficient is as follows: ; wherein is the specific heat ratio of steam.

[0028] In step S2, the pressure distribution adopts a geometric series decreasing distribution, i.e. ; that is, ; In step S2, the initial value of the pressure reduction stage is set to 1, and the pressure difference of each stage is calculated according to the pressure distribution, if the pressure difference of a certain stage is greater than the blockage pressure difference Then the decompression stage will be at the initial value. Add 1 to the previous step, calculate the pressure difference for each stage, and repeat this step until the pressure difference for each stage is less than the blocking pressure difference for the first time. Record the number of pressure-reducing stages of the control valve obtained at this point as . .

[0029] S3: Based on the pressure distribution at each stage calculated in S2, iterate the throttling area at each stage using computational fluid dynamics methods; the process is as follows: Figure 3 .

[0030] As a preferred embodiment of the present invention, the throttling area iteration method in this step is as follows: Setting the first The initial throttling area of ​​the multi-hole throttling sleeve is [value missing]. , The expression is as follows: ; in The pressure reduction stage in which the porous throttling sleeve is located. This refers to the valve diameter of the steam regulating valve.

[0031] Through the above inlet pressure Export pressure Based on the characteristics of the pressure difference distribution at each level, the first... The pressures before and after the multi-stage porous throttling sleeve are respectively , By inputting this as a boundary condition into computational fluid dynamics software, the first boundary condition can be calculated. Multi-stage porous throttling sleeve with a throttling area of The mass flow rate at that time is According to the law of conservation of mass, if the mass flow rate of the steam regulating valve is... Then the mass flow rate of each pressure-reducing structure is also ,like Then it is believed Can be used as the first The final throttling area of ​​the multi-hole throttling sleeve .

[0032] Otherwise if Then set ,Will The throttling area is used for computational fluid dynamics calculations in the next iteration to obtain the corresponding mass flow rate. ; Otherwise if Then set ,Will The throttling area is used for computational fluid dynamics calculations in the next iteration to obtain the corresponding mass flow rate. ; The boundary condition setting method of computational fluid dynamics in this step is as follows: The fluid inlet is set as a pressure inlet, the fluid outlet is set as a pressure outlet, the inlet temperature is the steam medium temperature, and the outlet temperature is consistent with the inlet temperature.

[0033] S4: Determine the optimal aperture of the throttling sleeve, and the process is shown in Figure 4 .

[0034] According to the aperture of the regulating valve, determine the recommended value of the aperture, select a suitable aperture near the recommended value, and the throttling aperture The recommended value is as follows: If , the throttling aperture The recommended value is 3mm; If , the throttling aperture The recommended value is 5mm; If , the throttling aperture The recommended value is 10mm.

[0035] According to the throttling area of each stage calculated in S3, calculate the number of throttling holes of each stage and arrange them, and the suitable aperture selection interval is , and the number of different apertures selected is 7, which must include the recommended aperture.

[0036] The number of throttling holes must satisfy the following inequality: ; Wherein represents the number of the th throttling hole.

[0037] The throttling hole mode needs to satisfy that the number of rows of throttling holes is even, if the number of holes is odd, then based on the calculated number of holes, one throttling hole is added, and the vertical distance between the centers of the adjacent two rows of throttling holes is to ensure the continuity of flow regulation.

[0038] The computational fluid dynamics method is used to obtain the noise level of the steam regulating valve corresponding to different apertures, and the boundary conditions of computational fluid dynamics are inlet pressure , and outlet pressure , and after repeating the noise calculation 7 times, the corresponding noise value under each aperture is obtained.

[0039] The function fitting aperture and noise corresponding curve is adopted, the function is a polynomial function, and the cubic function fitting is the preferred function type, and the definition domain of the function is The orifice hole diameter at the lowest noise level is obtained, and the best orifice hole diameter is obtained after rounding, the rounded orifice hole diameter should not be less than the orifice hole diameter corresponding to the minimum value of the function, and the rounded orifice hole diameter should be an integer multiple of 0.1 mm.

[0040] S5: On the basis of the minimum pressure drop number determined in S2, the steps of S2-S4 are repeated respectively by adding different numbers of pressure drop numbers, the pressure drop number with the lowest noise level under different pressure drop numbers is obtained, and the structure with the best noise control capability with the pressure drop number is taken as the final design structure.

[0041] The above-described embodiments are only a preferred scheme of the present application, and are not intended to limit the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, any technical scheme obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure, characterized in that, Specifically, the steps are as follows: S1: Obtain the valve type, operating parameters, and geometric parameters of the steam regulating valve; S2: Calculate the blocking pressure difference of the target steam regulating valve based on the set pressure distribution to obtain the minimum pressure reduction stage required by the target steam regulating valve under given operating conditions; S3: Based on the pressure distribution of each stage calculated in S2, iterate the throttling area of ​​each stage using computational fluid dynamics; S4: Determine the recommended orifice diameter based on the regulating valve diameter, select a suitable orifice diameter near the recommended value, calculate the number of throttling orifices at each stage based on the throttling area of ​​each stage calculated in S3, arrange them, obtain the noise level of the steam regulating valve corresponding to different orifice diameters using computational fluid dynamics, fit the orifice diameter and noise curve using a function to obtain the throttling orifice diameter with the lowest noise level, and round it to obtain the optimal throttling orifice diameter; S5: Based on the minimum pressure drop stage determined in S2, repeat steps S2-S4 for increasing different numbers of pressure drop stages to obtain the pressure drop stage with the lowest noise level under different pressure drop stages, and use the structure with the best noise control capability at this pressure drop stage as the final design structure.

2. The design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure according to claim 1, characterized in that, In S1, the operating parameters include the inlet temperature of the steam regulating valve. Inlet steam pressure outlet steam pressure Quality flow of demand Geometric parameters include the valve orifice diameter of the steam regulating valve. .

3. The design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure according to claim 1, characterized in that, In step S2, the blocking pressure differential of the steam regulating valve The expression is as follows: in The inlet steam pressure, This is the specific heat coefficient of steam. The differential pressure ratio coefficient for a control valve with an accessory fitting under choked flow conditions; when the dimensions of the control valve and the accessory fitting are the same, the... Simplified to ,in The differential pressure ratio coefficient of a control valve without auxiliary pipe fittings under choked flow conditions is determined by the valve type of the regulating valve; Based on air fluid with near atmospheric pressure and a specific heat ratio of 1.40, if the specific heat ratio of the fluid is not 1.40, then the specific heat ratio coefficient is used. The specific heat ratio is adjusted as a coefficient; The calculation expression is as follows: in This is the specific heat ratio of steam.

4. The design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure according to claim 1, characterized in that, In step S2, the pressure distribution adopts a geometrically decreasing distribution, that is... Right now Initial value of decompression stage Set to 1, calculate the pressure difference at each level based on the pressure distribution, if a certain level of pressure difference... Greater than the blocking pressure difference Then the decompression stage will be at the initial value. Add 1 to the previous step, calculate the pressure difference for each stage, and repeat this step until the pressure difference for each stage is less than the blocking pressure difference for the first time. Record the number of pressure-reducing stages of the control valve obtained at this point as . .

5. The design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure according to claim 1, characterized in that, The throttling area iteration method in step S3 is as follows: Setting the first The initial throttling area of ​​the multi-hole throttling sleeve is [value missing]. , The expression is as follows: in The pressure reduction stage in which the porous throttling sleeve is located. The valve diameter of the steam regulating valve. Through the above inlet pressure Export pressure Based on the characteristics of the pressure difference distribution at each level, the first... The pressures before and after the multi-stage porous throttling sleeve are respectively , By inputting this as a boundary condition into computational fluid dynamics software, the first boundary condition can be calculated. Multi-stage porous throttling sleeve with a throttling area of The mass flow rate at that time is According to the law of conservation of mass, if the mass flow rate of the steam regulating valve is... Then the mass flow rate of each pressure-reducing structure is also ,like Then it is believed Can be used as the first The final throttling area of ​​the multi-hole throttling sleeve Otherwise if Then set ,Will The throttling area is used for computational fluid dynamics calculations in the next iteration to obtain the corresponding mass flow rate. Otherwise if Then set ,Will The throttling area is used for computational fluid dynamics calculations in the next iteration to obtain the corresponding mass flow rate. .

6. The design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure according to claim 1, characterized in that, The boundary conditions for computational fluid dynamics in step S3 are set as follows: the fluid inlet is set as a pressure inlet, the fluid outlet is set as a pressure outlet, the inlet temperature is the steam medium temperature, and the outlet temperature is consistent with the inlet temperature.

7. The design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure according to claim 1, characterized in that, The throttling orifice in step S4 Recommended values ​​are as follows: like throttling orifice The recommended value is 3mm; if throttling orifice The recommended value is 5mm; if throttling orifice The recommended value is 10mm; the suitable aperture selection range is... The number of different apertures selected is 7, among which the recommended aperture must be included.

8. The design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure according to claim 7, characterized in that, Number of throttle orifices in step S4 The following inequalities must be satisfied: in Indicates the first The number of throttling orifices and the orifice arrangement must satisfy the condition that the number of orifice rows is even. If the number of orifices is odd, then add one more orifice to the calculated number of orifices, and the vertical distance between the centers of adjacent rows of orifices must be... To ensure the continuity of flow regulation.

9. The design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure according to claim 1, characterized in that, The computational fluid dynamics boundary condition in step S4 is the inlet pressure. Export pressure is The noise calculation was repeated 7 times to obtain the corresponding noise values ​​for each aperture; the function was a polynomial function, with cubic function fitting being the preferred function type; the domain of the function was... The rounded orifice diameter should not be less than the orifice diameter corresponding to the minimum value of the function, and the rounded orifice diameter should be an integer multiple of 0.1 mm.

10. The design method for a multi-hole throttling sleeve of a steam regulating valve with a multi-stage pressure drop structure according to claim 1, characterized in that, In step S5, different pressure drop stages are added, namely, adding one, two, and three stages respectively. The steam regulating valve structure with the added pressure drop stages is operated in steps S2-S4.

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