Valve inlet uniformity runner design method based on fluid diffusion effect

Abstract

The invention relates to a valve inlet uniformity flow channel design method based on the fluid diffusion effect, a flow channel structure of a valve inlet comprises a horizontal flow channel close to the inlet end and a vertical flow channel close to the outlet end, and the method comprises the following steps that firstly, a buffer mixed flow transition area is arranged between the horizontal flow channel and the vertical flow channel, the buffer mixed flow transition area comprises a cylindrical section communicated with the horizontal flow channel and a conical section communicated with the vertical flow channel; a transition area for buffering mixed flow is introduced between the horizontal inlet and the vertical main flow channel, so that the shrinkage nozzle effect and boundary layer separation caused by sudden shrinkage in a traditional structure are avoided, and the vertical flow channel of the inlet flow channel is in an axial symmetry layer flow state; therefore, the problems of vortex and non-uniform speed distribution at the outlet of the valve inlet runner are avoided, the piston part is ensured not to be subjected to fluid load in the horizontal direction, and the stability of the piston during opening is improved.

Description

Technical Field

[0001] The present application relates to the field of solenoid valve engineering technology, and in particular to a method for designing a uniform flow channel at a valve inlet based on a fluid diffusion effect. Background Art

[0002] In existing solenoid valve structures, the inlet flow channel is typically connected to a horizontal external pipe, while the flow channel within the valve core is mostly arranged vertically, inevitably resulting in a horizontal-vertical angle structure. Furthermore, in existing valve body designs, especially in solenoid valves (proportional valves, pneumatic control valves, and pilot servo valves) with high control precision requirements, the inlet flow channel is often viewed as a simple conduction and connection structure, rather than a functional area with a critical impact on flow field quality. The impact of the inlet flow channel structure on downstream flow is often overlooked during the design process, which can easily lead to the following problems:

[0003] 1. Uneven flow velocity distribution: When the fluid transfers from a larger diameter horizontal channel to a smaller diameter vertical channel, a "jet-like" flow will be formed in the corners and cross-sectional mutation areas, resulting in excessively high velocity in the center area and stagnant flow in the boundary area. The overall flow velocity profile is saddle-shaped or eccentric, resulting in nonlinear fluctuations in the flow rate of the solenoid valve with high control precision requirements as the opening changes.

[0004] 2. Eccentric force on the piston: Due to the asymmetric velocity field in front of the valve core (inlet flow channel outlet), the piston or valve plate is subjected to uneven fluid impact, generating a significant horizontal load, which in turn causes the piston to deviate laterally, resulting in jitter and affecting the stability of the flow.

[0005] 3. Magnetic circuit asymmetry and additional friction: In the structure where the piston is connected to the movable iron core, lateral offset will cause the iron core to deviate from the center of the magnetic axis, resulting in uneven magnetic field distribution or local saturation, further exacerbating the insufficient magnetic attraction required in the opening direction, and may even cause friction between the iron core and the side wall of the cavity, reducing the service life.

[0006] To solve the above problems, the following three solutions are adopted in the prior art:

[0007] 1. A centering spring is added between the piston and the movable core. However, as the solenoid valve's operating pressure increases, the centering function required by the spring also increases accordingly. This results in an increase in the thickness of the spring, which in turn increases the vertical load on the spring when the piston is opened, increasing the magnetic force required for opening the valve, or placing higher requirements on the pattern design of the spring. This significantly increases the design difficulty of the solenoid valve and places higher demands on its processing.

[0008] 2. By increasing the length of the vertical flow channel, the horizontal effect of the horizontal section flow channel on the fluid at the inlet and outlet of the flow channel is reduced, but this will increase the flow channel resistance and reduce the maximum flow value under the same inlet and outlet pressure difference conditions.

[0009] 3. Add a rectifier network structure at the outlet of the inlet flow channel. The eccentric flow field distribution in the vertical flow channel is alleviated through the rectifier network structure. This requires high processing accuracy and has a complex structure, which increases assembly costs and is difficult to promote in medium and low-cost products. Summary of the Invention

[0010] In order to solve the problems of uneven flow velocity distribution at the horizontal-vertical corner, eccentric force on the valve core piston and magnetic circuit offset in the existing solenoid valve structure proposed in the above background technology, the present application provides a valve inlet uniformity flow channel design method based on fluid diffusion effect.

[0011] The present application provides a valve inlet uniformity flow channel design method based on fluid diffusion effect, which adopts the following technical solutions:

[0012] A method for designing a uniform flow channel at a valve inlet based on a fluid diffusion effect, wherein the flow channel structure of the valve inlet includes a horizontal flow channel near the inlet end and a vertical flow channel near the outlet end. The method comprises the following steps:

[0013] Step 1: Setting a buffer mixed flow transition zone between the horizontal flow channel and the vertical flow channel. The buffer mixed flow transition zone includes a cylindrical section connected to the horizontal flow channel and a conical section connected to the vertical flow channel. The flow channel diameter of the buffer mixed flow transition zone is between the diameters of the horizontal flow channel and the vertical flow channel.

[0014] Step 2: According to the inlet diameter of the valve inlet , outlet diameter and design flow , calculate the average flow velocity at the inlet and outlet of the inlet flow channel; get

[0015] Average flow velocity at the inlet :

[0016] Average flow rate at outlet : ;

[0017] Step 3: Based on the average flow rate, fluid type and fluid viscosity obtained in step 2 , calculate the Reynolds number , and combined with the Reynolds number and compressibility correction factor , determine the comprehensive correction factor ; Step 4: Based on the comprehensive correction factor and the Reynolds number , calculate the structural parameters of the buffer mixed flow transition zone, including the diameter of the cylindrical section , cylindrical segment height and the height of the tapered section , used to improve the uniformity of fluid velocity distribution in the valve inlet flow channel, where Cylindrical segment diameter :

[0018] Cylindrical segment height :

[0019] Cone section height : .

[0020] By adopting the above technical solution, a buffer mixed flow transition zone is set between the horizontal flow channel and the vertical flow channel, and combined with the calculated structural parameters (including the diameter and height of the cylindrical section and the height of the conical section), the uneven flow velocity distribution, flow disturbance and local vortex phenomenon caused by the sudden change of the flow channel cross-section can be effectively reduced, the velocity field at the valve inlet can be homogenized, and the fluid response consistency and control stability of the overall valve system can be improved. It is particularly suitable for application scenarios with high precision requirements in hydraulic or pneumatic control systems.

[0021] Optionally, in step 3, the fluid type is liquid, and its density is , the calculated Reynolds number for:

[0022] Compressibility correction factor for liquids =1, and the comprehensive correction factor is obtained for: .

[0023] By adopting the above technical solution, specific modeling is performed for working conditions where the fluid type is liquid. Liquid-specific density parameters and compressibility correction coefficients are used to more accurately reflect the inertial effects and flow velocity changes generated by the liquid during the flow process, making the calculated Reynolds number and comprehensive correction factor more consistent with the actual flow characteristics of the liquid, thereby further optimizing the adaptability and effectiveness of the structural design of the buffer mixed flow transition zone and improving the flow channel uniformity under the liquid medium.

[0024] Optionally, in step 3, the fluid type is gas, and its density for:

[0025] Speed ​​of sound for:

[0026] in, is the gas inlet pressure, is the gas inlet temperature, is the gas constant, is the gas specific heat ratio; Calculated Reynolds number for:

[0027] Gas compressibility correction factor for:

[0028] Get the comprehensive correction factor for: .

[0029] By adopting the above technical solution, a mathematical model is established for gas working conditions, combining gas density, sound velocity and compressibility factors, which can accurately reflect the compressibility influence and impact characteristics of the airflow in the flow channel transition area. By introducing the correction coefficient and sound velocity, the obtained correction factor is more adapted to the gas flow characteristics, thereby ensuring that the homogenizing effect of the buffer mixing structure in high-pressure and high-speed gas media is still significant, which is conducive to improving the versatility and response stability of the valve structure in the pneumatic control system.

[0030] Optionally, the inlet diameter of the valve inlet, the cylindrical section diameter of the buffer mixed flow transition zone, and the outlet diameter of the valve inlet decrease in sequence.

[0031] By adopting the above technical solution, the diameter of each section of the valve inlet structure is limited to decrease successively from the inlet end to the outlet end. In the process of the fluid entering the transition zone from the horizontal flow channel and then flowing to the vertical flow channel, the contraction nozzle effect and boundary layer separation caused by sudden contraction in the traditional structure can be avoided by buffering the mixed flow transition zone, so that the vertical flow channel of the inlet flow channel is in an "axisymmetric laminar state", thereby avoiding the problems of vortex and uneven velocity distribution at the outlet of the valve inlet flow channel, ensuring that the piston part will not be subjected to the fluid load in the horizontal direction, and improving the stability of the piston when it is opened.

[0032] Optionally, the cylindrical section and the conical section in the buffer mixed flow transition zone are coaxially arranged, and the buffer mixed flow transition zone and the vertical flow channel are coaxially arranged to ensure that the velocity direction of the fluid gradually changes during the transition process.

[0033] By adopting the above technical solution, by setting the cylindrical section and the conical section of the buffer mixed flow transition zone coaxially, and keeping the whole coaxial with the vertical flow channel, it helps to ensure that the fluid maintains a stable axial transition path in the flow direction, thereby avoiding additional eddies and shear stresses caused by structural eccentricity or sudden changes in flow direction, further improving the uniformity of the flow velocity vector direction, and helping to improve the dynamic response performance of the valve core or control mechanism, and improving the accuracy and efficiency of the system operation.

[0034] Optionally, the buffer mixed flow transition zone is located at the junction of the horizontal flow channel and the vertical flow channel.

[0035] By adopting the above technical solution, a structural transition buffer is provided at the location where the fluid flow direction suddenly changes, so that the fluid can smoothly transition when passing through, effectively weakening the vortex, local separation and velocity eccentricity caused by the right-angle turn, thereby optimizing the flow field structure at the inlet and improving the overall flow stability of the valve body and the consistency of downstream response.

[0036] In summary, this application includes at least one of the following beneficial technical effects:

[0037] The present invention avoids the contraction nozzle effect and boundary layer separation caused by sudden contraction in the traditional structure by introducing a buffered mixed flow transition area between the horizontal inlet and the vertical main flow channel, so that the vertical flow channel of the inlet flow channel is in an "axisymmetric laminar state", thereby avoiding the problems of vortex and uneven velocity distribution at the inlet flow channel outlet of the valve, ensuring that the piston part will not be subjected to horizontal fluid loads, and improving the stability of the piston when it is opened.

[0038] The present invention introduces parameters such as the inlet diameter, outlet diameter and design flow rate, and combines them with physical properties such as fluid viscosity, density, and compressibility to calculate the Reynolds number and comprehensive correction factor, thereby achieving accurate determination of the key structural dimensions of the buffer mixed flow transition zone, so that the fluid forms a relatively symmetrical and stable flow field before entering the valve core structure, which helps to improve the response linearity and adjustment stability of high-precision control systems such as proportional valves and pneumatic control valves.

[0039] The present invention constructs independent Reynolds number and compressibility correction models for liquids and gases respectively. The designed structural parameters can adapt to fluids with different densities, viscosities and compressibility levels, and has the advantages of wide applicability and strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of the valve inlet flow channel structure of the present invention;

[0041] Figure 2 It is a cross-sectional view of the valve inlet flow channel structure of the present invention.

[0042] Description of reference numerals:

[0043] 1. Inlet end; 2. Horizontal flow channel; buffer mixed flow transition zone; 301. Cylindrical section; 302. Conical section; 4. Vertical flow channel; 5. Outlet end. DETAILED DESCRIPTION

[0044] The present application is further described in detail below with reference to the accompanying drawings.

[0045] like Figure 1-2 As shown, the embodiment of the present application discloses a method for designing a uniform flow channel at a valve inlet based on a fluid diffusion effect. The flow channel structure of the valve inlet includes a horizontal flow channel 2 near the inlet end 1 and a vertical flow channel 4 near the outlet end 5. The method includes the following steps:

[0046] Step 1: A buffer mixing transition zone 3 is set between the horizontal flow channel 2 and the vertical flow channel 4, and the buffer mixing transition zone 3 includes a cylindrical section 301 connected to the horizontal flow channel 2 and a conical section 302 connected to the vertical flow channel 4. The flow channel diameter of the buffer mixing transition zone 3 is between the diameter sizes of the horizontal flow channel 2 and the vertical flow channel 4. Specifically, in this embodiment, the buffer mixing transition zone 3 is located at the junction of the horizontal flow channel 2 and the vertical flow channel 4, and the diameter of the inlet end 1 of the valve inlet, the diameter of the cylindrical section 301 of the buffer mixing transition zone 3, and the diameter of the outlet end 5 of the valve inlet decrease successively; the cylindrical section 301 and the conical section 302 in the buffer mixing transition zone 3 are coaxially arranged, and the buffer mixing transition zone 3 and the vertical flow channel 4 are coaxially arranged to ensure that the velocity direction of the fluid gradually changes during the transition process.

[0047] Step 2: Based on the diameter of the valve inlet port 1 , outlet diameter 5 and design flow , calculate the average flow velocity at the inlet and outlet of the inlet flow channel; In this example, the diameter of the inlet port 1 ; Outlet port 5 diameter ; Design flow ; The average flow velocity at inlet 1 is obtained :

[0048] Average flow rate at outlet 5 : ; Step 3: Based on the average flow rate, fluid type and fluid viscosity obtained in step 2 , calculate the Reynolds number , and combined with the Reynolds number and compressibility correction factor , determine the comprehensive correction factor ; Step 4: Based on the comprehensive correction factor and the Reynolds number , calculate the structural parameters of the buffer mixed flow transition zone 3, including the diameter of the cylindrical section 301 , cylindrical section 301 height and the height of the tapered section 302 , used to improve the uniformity of fluid velocity distribution in the valve inlet flow channel, where Cylindrical section 301 diameter :

[0049] Height of cylindrical section 301 :

[0050] Height of tapered section 302 : .

[0051] Specifically, in step three, the fluid type is divided into two cases: liquid and gas.

[0052] 1. When the fluid is liquid (taking water as an example): The density of the fluid is ; Fluid viscosity ; Reynolds number:

[0053] Comprehensive correction factor:

[0054] The liquid is considered as an incompressible fluid ; Then the diameter of the cylindrical section 301 is obtained :

[0055] Height of cylindrical section 301 :

[0056] Height of tapered section 302 : .

[0057] 2. When the fluid is gas (taking air as an example), the known conditions are: Inlet pressure ; Inlet temperature ; Gas constant R = 287 J / (kg·K); Gas specific heat ratio ; Fluid viscosity ; Gas state correction (density and sound speed):

[0058] Reynolds number:

[0059] Compression correction factor:

[0060] Comprehensive correction factor:

[0061] Then the diameter of the cylindrical section 301 is obtained :

[0062] Height of cylindrical section 301 :

[0063] Height of tapered section 302 : .

[0064] Based on the above calculations, the specific structural parameters of the buffer mixed flow transition zone 3 in the two cases where the fluid is water and air can be obtained, as shown in the following table:

[0065]

[0066] The above calculations are the most appropriate values ​​obtained based on known conditions. In actual design, adaptive changes can be made based on factors such as processing accuracy. For example, if the height values ​​(the height of the cylindrical section 301 and the height of the conical section 302) need to be adjusted or rounded, it is recommended to round the values ​​upward (that is, increasing the height value has less impact than decreasing it).

[0067] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A valve inlet uniformity flow channel design method based on fluid diffusion effect, characterized in that: The flow channel structure of the valve inlet includes a horizontal flow channel (2) near the inlet end (1) and a vertical flow channel (4) near the outlet end (5). The method includes the following steps: Step 1: a buffer mixed flow transition zone (3) is provided between the horizontal flow channel (2) and the vertical flow channel (4), wherein the buffer mixed flow transition zone (3) comprises a cylindrical section (301) connected to the horizontal flow channel (2) and a conical section (302) connected to the vertical flow channel (4), and a flow channel diameter of the buffer mixed flow transition zone (3) is between the diameters of the horizontal flow channel (2) and the vertical flow channel (4); Step 2: Based on the diameter of the valve inlet (1) , outlet port (5) diameter and design flow , calculate the average flow velocity at the inlet and outlet of the inlet flow channel; get Average flow velocity at the inlet (1) : Average flow velocity at outlet (5) : ； Step 3: Based on the average flow rate, fluid type and fluid viscosity obtained in step 2 , calculate the Reynolds number , and combined with the Reynolds number and compressibility correction factor , determine the comprehensive correction factor ; Step 4: Based on the comprehensive correction factor and the Reynolds number , calculate the structural parameters of the buffer mixed flow transition zone (3), including the diameter of the cylindrical section (301) , cylindrical section (301) height and the height of the tapered section (302) , used to improve the uniformity of fluid velocity distribution in the valve inlet flow channel, where Cylindrical section (301) diameter : Height of cylindrical section (301) : Height of tapered section (302) : 。 2. The method for designing uniform flow channels at valve inlets based on fluid diffusion effect according to claim 1, characterized in that: In step 3, the fluid type is liquid, and its density is , the calculated Reynolds number for: Compressibility correction factor for liquids =1, and the comprehensive correction factor is obtained for: 。 3. The method for designing uniform flow channels at valve inlets based on fluid diffusion effect according to claim 1, characterized in that: In step 3, the fluid type is gas, and its density for: Speed ​​of sound for: in, is the gas inlet pressure, is the gas inlet temperature, is the gas constant, is the gas specific heat ratio; Calculated Reynolds number for: Gas compressibility correction factor for: Get the comprehensive correction factor for: 。 4. The method for designing a uniform flow channel at a valve inlet based on a fluid diffusion effect according to claim 1, characterized in that: The diameter of the inlet end (1) of the valve inlet, the diameter of the cylindrical section (301) of the buffer mixed flow transition zone (3), and the diameter of the outlet end (5) of the valve inlet decrease in sequence.

5. The method for designing uniform flow passages at valve inlets based on fluid diffusion effect according to claim 1, characterized in that: The cylindrical section (301) and the conical section (302) in the buffer mixed flow transition zone (3) are coaxially arranged, and the buffer mixed flow transition zone (3) and the vertical flow channel (4) are coaxially arranged to ensure that the velocity direction of the fluid gradually changes during the transition process.

6. The method for designing uniform flow channels at valve inlets based on fluid diffusion effect according to claim 1, characterized in that: The buffer mixed flow transition zone (3) is located at the junction of the horizontal flow channel (2) and the vertical flow channel (4).

Images