Structure optimization design method for vortex street flow sensor

Abstract

The invention discloses a vortex street flow sensor structure optimization design method. The method comprises the following steps: constructing a simulation structure model of a vortex street flow sensor; constructing an acceleration axial distribution curve equation of the vortex street flow sensor structure; randomly setting the position of the maximum acceleration of the curve contraction structure based on the maximum acceleration limit value of the fluid in the vortex flow sensor, and setting the length of the combined contraction section component based on the size of the vortex flow sensor; based on the acceleration axial distribution curvilinear equation, solving and obtaining structural design parameters of the vortex street flow sensor to confirm a structural contraction curvilinear equation; obtaining the fluid flow velocity of the vortex street flow sensor according to the structure shrinkage curve equation; on the basis of the constructed structure evaluation index model, the structure optimization design meeting the preset expected index is determined according to the fluid flow velocity and the structure design parameters, the stable transition of the fluid flow velocity can be ensured, the turbulence and fluid separation phenomena can be reduced, the flexible optimization design of the vortex street flow sensor structure is realized according to different occasions, and the design efficiency is improved. The stability and the measurement precision of vortex street signals of the vortex street flow sensor are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of vortex flowmeters, and in particular to a structural optimization design method for a vortex flow sensor. Background Art

[0002] Vortex flowmeter is a flow measurement instrument widely used in petroleum, chemical, electric power, water treatment and other industries. It has the advantages of simple structure, high precision, wide application range and easy maintenance. The core principle of vortex flowmeter is to use the Karman vortex phenomenon generated when the fluid passes through the contraction section, and to achieve flow measurement by measuring the relationship between the frequency of the vortex and the flow rate. The stability and accuracy of the vortex signal are closely related to the design of the contraction section. Therefore, the optimization design of the contraction section is the key to improving the performance of the vortex flowmeter. In fluid mechanics, the turbulence of the fluid is an important parameter to measure the degree of flow chaos. When the turbulence is high, the flow of the fluid becomes chaotic and unstable, and the formation of the vortex may be disturbed, resulting in vortex frequency fluctuations, which in turn affects the measurement accuracy of the flow; when the turbulence is low, the liquid flows more smoothly, and the vortex signal is stable and easy to extract, thereby improving the accuracy and reliability of the measurement. Therefore, when designing the contraction section of the vortex flowmeter, it is necessary to focus on the influence of the fluid turbulence on the stability and accuracy of the measurement and the overall performance of the flowmeter.

[0003] At present, the most common contraction section structure designs in vortex flowmeters include three forms: straight necking, cross-sectional necking and de-curved necking. The straight necking structure adopts a simple linear contraction shape to gradually reduce the cross-sectional area of ​​the pipe. This structure has the advantages of simple design and low manufacturing cost, but this structure will cause the fluid velocity to increase continuously in the contraction section, and the fluid will still have acceleration when entering the measurement area, resulting in separation or turbulence. This will cause the flow velocity of the fluid to be unevenly distributed, forming vortices or local turbulence, causing measurement errors, and thus affecting the stability of the vortex signal.

[0004] The cross-sectional necking structure does not have a traditional contraction section, but directly reduces the pipe diameter from a large size to a small size, causing the fluid flow rate to accelerate rapidly to the maximum value. This change mainly occurs at the entrance of the measuring section. Therefore, flow layers with different flow rates will appear at the entrance of the measuring section, which will trigger the formation of vortices and increase the turbulence of the fluid. The curved necking structure uses a gradual curve shape to guide the fluid flow, which can better reduce the sudden change of flow rate and avoid violent turbulence and separation. Therefore, the vortex street signal is relatively stable. However, the manufacturing process of the curved contraction is relatively complicated, and for applications with a large flow range, its contraction ratio may be insufficient, resulting in limited measurement accuracy.

[0005] In summary, the current vortex flowmeter structures cannot ensure a smooth transition of the fluid flow rate while reducing turbulence and fluid separation. Summary of the invention

[0006] The present invention provides a method for optimizing the structure design of a vortex flow sensor to overcome the above technical problems.

[0007] In order to achieve the above object, the technical solution of the present invention is:

[0008] A method for optimizing the structure of a vortex flow sensor comprises the following steps:

[0009] S1: Construct the simulation structure model of vortex flow sensor;

[0010] The simulation structure model includes a stabilizing segment component for rectifying the fluid, a combined contraction segment component for optimizing the flow velocity distribution of the fluid output by the stabilizing segment component and reducing the turbulence to obtain a fluid vortex signal, and a measuring segment component for detecting the fluid vortex signal.

[0011] The combined contraction section component includes a linear contraction structure and a curved contraction structure;

[0012] S2: Construct the acceleration axial distribution curve equation of the vortex flow sensor structure;

[0013] S3: Based on the maximum acceleration limit value of the fluid in the vortex flow sensor, the maximum acceleration position of the curve contraction structure is randomly set, and the length of the combined contraction section component is set based on the size of the vortex flow sensor;

[0014] S4: Based on the acceleration axial distribution curve equation, according to the location of the maximum acceleration and the length of the combined contraction section component, solve and obtain the structural design parameters of the vortex flow sensor, and confirm the structural contraction curve equation based on the structural design parameters;

[0015] S5: Obtain the fluid flow rate of the vortex flow sensor according to the structural contraction curve equation;

[0016] S6: Based on the constructed structural evaluation index model, confirm whether the preset expected indicators are met according to the fluid flow rate and structural design parameters;

[0017] If the preset expected index is met, the structural contraction ratio of the vortex flow sensor is confirmed based on the fluid flow rate, and the confirmed structural contraction ratio, the position of the maximum acceleration of the curve contraction structure set at this time, and the length of the combined contraction section component are the results of the geometric structure optimization design of the vortex flow sensor;

[0018] Otherwise, the position of the maximum acceleration and the length of the contraction section are reselected, and step S4 is repeated.

[0019] Furthermore, the method for constructing the acceleration axial distribution curve equation of the vortex flow sensor structure in S2 specifically includes the following steps:

[0020] S21: obtaining the axial acceleration function and function restriction condition of the vortex flow sensor structure;

[0021] The axial acceleration function includes the acceleration axial distribution function of the linear contraction section structure and the acceleration axial distribution function of the curved contraction section structure, and its expression is:

[0022] l1=a1x(1)

[0023] l2=a2x 2 +b2x+c2(2)

[0024] Where: l1 represents the acceleration of the linear contraction section; l2 represents the acceleration of the curved contraction section; a1, a2, b2, c2 represent the constant coefficients of the axial acceleration function; x represents the distance from the section to the entrance of the combined contraction section;

[0025] The expression of the function restriction condition is

[0026] a1>0,a2<0;b2>0(3)

[0027]

[0028] x2=L(7)

[0029] Where: x1, x2 represent the analytical solution of the acceleration axial distribution function of the contraction section of the curve; L represents the length of the combined contraction section; m represents the position where the acceleration reaches the maximum;

[0030] S22: Simplify equation (4) to get the expression:

[0031]

[0032] Combining equation (8) with equation (6), we can get equation (9):

[0033]

[0034] S23: Combining equations (9), (6) and (7), we can obtain equation (10):

[0035]

[0036] And further combining equation (10) and equation (6) we can get equation (11):

[0037]

[0038] S24: Combining equation (11) with equation (10), we can get equation (12):

[0039]

[0040] And further combining equation (12) and equation (8) we can get equation (13):

[0041]

[0042] S25: According to step S24, the acceleration axial distribution curve equation of the vortex flow sensor structure is constructed, and its expression is:

[0043]

[0044] Furthermore, the S4 specifically includes the following steps:

[0045] S41: Obtain the one-dimensional fluid acceleration equation for the fluid input into the vortex flow sensor, which is expressed as follows:

[0046]

[0047] And simplify it to obtain formula (16):

[0048] Kadx=udu(16)

[0049] Where: u represents the fluid flow rate; K represents the structural design parameters of the vortex flow sensor to be solved; a represents the fluid acceleration;

[0050] S42: Substitute equation (14) into equation (16) for piecewise integration operation to solve and obtain the fluid flow field, which is expressed as

[0051] In the range of x≤m, when x=m, u=u1, and the fluid flow field is obtained as:

[0052] u1 2 =u0 2 +Km 2 (Lm) 2 (17)

[0053] In the range of m<x≤L, when x=L, u=u2, the fluid flow field is obtained as:

[0054]

[0055] S43: Combine equation (17) and equation (18) to obtain the structural design parameters of the vortex flow sensor, which is expressed as

[0056]

[0057] The obtained structural design parameters of the vortex flow sensor are substituted into equations (17) and (18) to obtain the structural contraction curve equation of the vortex flow sensor.

[0058] Furthermore, in S6, based on the constructed structural evaluation index model, it is confirmed whether the preset expected index is met according to the fluid flow rate and the structural design parameters, specifically:

[0059] Based on the constructed structural evaluation index model, confirm whether the preset expected indicators are met according to the fluid flow rate and structural design parameters;

[0060] And the preset expected index includes a preset vortex frequency threshold and a preset volume flow threshold;

[0061] If the preset expected index is met, the structural contraction ratio of the vortex flow sensor is confirmed based on the fluid flow rate, and the confirmed structural contraction ratio, the position of the maximum acceleration of the curve contraction structure set at this time, and the length of the combined contraction section component are the results of the geometric structure optimization design of the vortex flow sensor;

[0062] And the expression for confirming the structural contraction ratio of the vortex flow sensor is:

[0063] u0S0=u1S1=u2S2=n(20)

[0064] Wherein: n represents the contraction ratio; u0 represents the velocity of the fluid flowing into the combined contraction section component; S0 represents the cross-sectional area of ​​the fluid flowing into the combined contraction section component; u2 represents the velocity of the fluid flowing out of the combined contraction section component; S2 represents the cross-sectional area of ​​the fluid flowing out of the combined contraction section component; u1 represents the velocity at the point m where the fluid acceleration is the largest on the contraction section component; S1 represents the cross-sectional area at the point m where the fluid acceleration is the largest on the contraction section component;

[0065] Otherwise, the position of the maximum acceleration and the length of the contraction section are reselected, and step S4 is repeated.

[0066] Furthermore, the structural evaluation index model constructed in S6 is expressed as

[0067]

[0068] Where: f represents the vortex frequency; U represents the fluid flow rate, which is the output of the structural contraction curve equation of the vortex flow sensor; D represents the characteristic size of the vortex generator, i.e., the combined contraction section component; S t represents the Strouhal number and is a constant; Q represents the volume flow rate of the vortex flow sensor; K represents the structural design parameters of the vortex flow sensor.

[0069] Beneficial effect: The present invention provides a method for optimizing the design of the structure of a vortex flow sensor. By combining a contraction section component, that is, combining a linear contraction structure with a curved contraction structure, the manufacturing complexity and cost are reduced while reducing the sharp change in flow velocity during the contraction process, ensuring that the fluid can enter the measuring section component smoothly and without eddy currents. The structural design parameters of the vortex flow sensor are solved and obtained based on the acceleration axial distribution curve equation to confirm the structural contraction curve equation and then obtain the fluid flow velocity of the vortex flow sensor; based on the constructed structural evaluation index model, the contraction ratio, contraction section length and maximum position of the fluid acceleration that meet the preset expected indicators are confirmed according to the fluid flow velocity and the structural design parameters, so as to realize flexible optimization design of the vortex flow sensor structure according to different occasions, thereby providing more accurate and stable measurement results under various complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0071] Figure 1 A flow chart of the structural optimization design method of the vortex flow sensor of the present invention;

[0072] Figure 2 Schematic diagram of the structural model of the vortex flow sensor in this embodiment;

[0073] Figure 3 This is a schematic structural diagram of the combined contraction section component in this embodiment;

[0074] Figure 4 : is the axial acceleration distribution curve diagram in this embodiment;

[0075] Figure 5 This is a flowchart of the overall design process of the vortex flow sensor structure in this embodiment. DETAILED DESCRIPTION

[0076] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of 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.

[0077] This embodiment provides a method for optimizing the structure design of a vortex flow sensor. Figures 1 to 3 As shown, the specific steps include:

[0078] S1: Construct the simulation structure model of vortex flow sensor;

[0079] The simulation structure model includes a stabilizing segment component for rectifying the fluid, a combined contraction segment component for optimizing the flow velocity distribution of the fluid output by the stabilizing segment component and reducing the turbulence to obtain a fluid vortex signal, and a measuring segment component for detecting the fluid vortex signal, and the combined contraction segment component includes a linear contraction structure and a curved contraction structure.

[0080] Specifically, according to the fluid turbulence theory, in this embodiment, in the straight contraction section, the fluid acceleration is greater than zero and is increasing all the time, and the velocity reaches the maximum at the entrance of the measuring section. There are velocity differences between the layers and turbulence exists; in the curved contraction section, the fluid acceleration is greater than zero and shows a trend of gradually increasing from zero, reaching a maximum value, and then gradually decreasing. Ideally, the fluid acceleration in the contraction section increases from zero to a maximum value, and then decreases to zero. This means that the flow velocity of the fluid in the contraction section is constantly increasing, and at the moment when the fluid flows out of the contraction section, the flow velocity between the flow layers is consistent, there is no velocity difference, and the turbulence degree of the fluid remains unchanged. Therefore, the new contraction section structure designed in this embodiment, that is, the combined contraction section component, adopts a front straight contraction and a rear curved contraction to ensure that there is no turbulence when the fluid enters the measuring section; such as Figure 2As shown in the figure, the functions of the stabilizing section are as follows: (1) Rectification: The stabilizing section can eliminate the uneven velocity distribution or turbulence caused by external interference (such as elbows, valves, etc.) before the fluid enters the flow meter, so that the fluid forms a uniform and stable velocity field; (2) Reduce turbulence: The stabilizing section reduces the turbulence of the fluid by eliminating excess vortices or local turbulence, thereby providing a stable flow environment for the generation of vortex signals; (3) Optimize the conditions for vortex generation: By stabilizing the flow velocity and pressure distribution, the conditions for vortex formation are ensured to be more ideal, thereby improving the measurement accuracy and signal stability. The combined contraction section is a design that combines a linear contraction structure with a curved contraction structure. Its main function is to optimize the velocity distribution of the fluid and reduce the turbulence. The specific functions are: (1) Smooth transition of flow velocity: The combined design makes the change of fluid velocity from a large cross section to a small cross section smoother, reducing turbulence or separation caused by sudden contraction; (2) Pressure loss control: Reduce the pressure drop when the fluid flows through the contraction section and reduce energy loss; (3) Improve measurement accuracy: Provide uniform and stable flow field conditions for subsequent measurement sections to ensure that the generation of vortex street signals is stable and reliable; (4) Adapt to different flow ranges: The combined design can adapt to the measurement requirements of different flow velocities and flow rates, providing a wider range of applications. The measuring section component is the area in the vortex flowmeter that is directly used to detect the vortex signal of the fluid. Its main function is to collect vortex signals and convert them into measurable physical quantities. Its specific functions are: (1) Vortex signal generation: The measuring section induces the fluid to generate a Karman vortex street through the built-in vortex generator, and the vortex signal is clearly and stably formed in this section; (2) Signal acquisition and transmission: The measuring section is equipped with a sensor to detect the frequency, amplitude and other characteristics of the vortex street, and convert the signal into an electrical signal for output; (3) Flow calculation: The vortex frequency collected by the measuring section is proportional to the flow rate of the fluid. Based on this relationship, the flow rate of the fluid can be obtained; (4) Ensure measurement stability: The design of the measuring section directly affects the quality and stability of the vortex signal, and plays a decisive role in the measurement accuracy of the overall flowmeter; and the measuring section component is provided with a generator A, which is one of the core components of the vortex flowmeter. Its main function is to induce the fluid to form a stable Karman vortex street, thereby realizing flow measurement.

[0081] S2: Construct the acceleration axial distribution curve equation of the vortex flow sensor structure, which specifically includes the following steps

[0082] S21: obtaining the axial acceleration function and function restriction condition of the vortex flow sensor structure;

[0083] The axial acceleration function includes the acceleration axial distribution function of the linear contraction segment and the acceleration axial distribution function of the curved contraction segment, and its expression is:

[0084] l1=a1x(1)

[0085] l2=a2x2 +b2x+c2(2)

[0086] In the formula: l1 represents the acceleration function of the straight contraction section; l2 represents the acceleration function of the curve contraction section, and passes through the point (L, 0); a1, a2, b2, c2 represent the constant term coefficients of the axial acceleration function; x represents the distance of the cross section from the entrance of the combined contraction section construction; this embodiment is based on the design concept of the wind tunnel contraction section and the ideal fluid flow equation. It is necessary to determine an axial acceleration of the fluid in the structure, calculate the entire flow field, and select a suitable streamline as the contraction section wall curve. Since the combined contraction section designed in this embodiment ends with curve contraction, the acceleration is 0 in an ideal state; due to the characteristics of curve contraction, the flow velocity at the end of the curve contraction section changes relatively slowly. Therefore, at the end of the contraction section, the flow velocity reaches a stable value, and the fluid no longer undergoes an acceleration process, so the acceleration is zero in an ideal state. Therefore, the axial acceleration function is determined to be a combination of a direct proportional function passing through the origin and a quadratic function, where the quadratic function opens downward, the direct proportional function is coaxial with the quadratic function, and the highest point coincides with the vertex of the quadratic function; the combined curve is as follows Figure 3 As shown, a represents the fluid acceleration, and x represents the distance from the cross section to the inlet of the contraction section. Figure 3 The new combined contraction section designed based on the central axial acceleration distribution curve is as follows Figure 2 As shown;

[0087] The expression of the function restriction condition is

[0088] a1>0,a2<0;b2>0(3)

[0089]

[0090]

[0091] x2=L(7)

[0092] Where: x1, x2 represent the analytical solution of the acceleration axial distribution function of the contraction section of the curve; L represents the length of the combined contraction section; m represents the position where the acceleration reaches the maximum;

[0093] S22: Simplify equation (4) to get the expression:

[0094]

[0095] Combining equation (8) with equation (6), we can get equation (9):

[0096]

[0097] S23: Combining equations (9), (6) and (7), we can obtain equation (10):

[0098]

[0099] And further combining equation (10) and equation (6) we can get equation (11):

[0100]

[0101] S24: Combining equation (11) with equation (10), we can get equation (12):

[0102]

[0103] And further combining equation (12) and equation (8) we can get equation (13):

[0104]

[0105] S25: According to step S24, the acceleration axial distribution curve equation of the vortex flow sensor structure is constructed, and its expression is:

[0106]

[0107] S3: Based on the maximum acceleration limit value of the given fluid in the vortex flow sensor, the maximum acceleration position of the curve contraction structure is randomly set, and the length of the combined contraction section component is randomly set based on the size of the vortex flow sensor;

[0108] S4: Based on the acceleration axial distribution curve equation, according to the location of the maximum acceleration and the length of the combined contraction section component, solve and obtain the structural design parameters of the vortex flow sensor, and confirm the structural contraction curve equation based on the structural design parameters, which specifically includes the following steps:

[0109] S41: Obtain the one-dimensional fluid acceleration equation for the fluid input into the vortex flow sensor, which is expressed as follows:

[0110]

[0111] And simplify it to obtain formula (16):

[0112] Kadx=udu(16)

[0113] Where: u represents the fluid flow rate; K represents the structural design parameters of the vortex flow sensor to be solved; a represents the fluid acceleration;

[0114] S42: Substitute equation (14) into equation (16) for piecewise integration operation to solve and obtain the fluid flow field, which is expressed as

[0115] In the range of x≤m, when x=m, u=u1, and the fluid flow field is obtained as:

[0116] u1 2 =u0 2 +Km 2 (Lm) 2 (17)

[0117] In the range of m<x≤L, when x=L, u=u2, the fluid flow field is obtained as:

[0118]

[0119] S43: Combine equation (17) and equation (18) to obtain the structural design parameters of the vortex flow sensor, which is expressed as

[0120]

[0121] Substitute the obtained structural design parameters of the vortex flow sensor into equations (17) and (18) to obtain the structural contraction curve equation of the vortex flow sensor; Figure 4 As shown, this embodiment is based on the structural contraction curve equation of the vortex flow sensor, and can adjust the new contraction section structure proposed by the present invention by selecting a suitable contraction ratio n, contraction section length L and maximum fluid acceleration position m according to different actual conditions;

[0122] S5: Obtain the fluid flow rate of the vortex flow sensor according to the structural contraction curve equation;

[0123] S6: Based on the constructed structural evaluation index model, confirm whether the preset expected indicators are met according to the fluid flow rate and structural design parameters;

[0124] In a specific embodiment, the constructed structural evaluation index model in S6 is used to determine whether the preset expected index is met according to the fluid flow rate and the structural design parameters. Specifically,

[0125] Based on the constructed structural evaluation index model, confirm whether the preset expected indicators are met according to the fluid flow rate and structural design parameters;

[0126] And the preset expected index includes a preset vortex frequency threshold and a preset volume flow threshold;

[0127] The structural evaluation index model specifically constructed is expressed as follows:

[0128]

[0129] Where: f represents the vortex frequency; U represents the fluid flow rate, which is the output of the structural contraction curve equation of the vortex flow sensor; D represents the characteristic size of the vortex generator, i.e., the combined contraction section component; S trepresents the Strouhal number and is a constant; Q represents the volume flow rate of the vortex flow sensor; K represents the structural design parameters of the vortex flow sensor;

[0130] If the preset expected index is met, the structural contraction ratio of the vortex flow sensor is confirmed based on the fluid flow rate, and the confirmed structural contraction ratio, the position of the maximum acceleration of the curve contraction structure set at this time, and the length of the combined contraction section component are the results of the geometric structure optimization design of the vortex flow sensor;

[0131] And the expression for confirming the structural contraction ratio of the vortex flow sensor is:

[0132] u0S0=u1S1=u2S2=n(20)

[0133] Wherein: n represents the contraction ratio; u0 represents the speed of the fluid flowing into the combined contraction section component; S0 represents the cross-sectional area of ​​the fluid flowing into the combined contraction section component; u2 represents the speed of the fluid flowing out of the combined contraction section component; S2 represents the cross-sectional area of ​​the fluid flowing out of the combined contraction section component; u1 represents the speed at the point m where the fluid acceleration is maximum on the contraction section component; S1 represents the cross-sectional area at the point m where the fluid acceleration is maximum on the contraction section component; the cross-sectional velocity uniformity refers to the degree of difference in the flow velocity of the fluid at each position within a certain cross-section, and the standard for judging the appropriate contraction ratio is whether the cross-sectional velocity uniformity is optimal (that is, the degree of difference in the flow velocity at each position is the lowest); the cross-sectional velocity uniformity under different situations and different contraction ratios will be different, so it is necessary to design the cross-sectional area and contraction ratio according to the actual situation and the structural contraction curve equation of the vortex flow sensor;

[0134] Otherwise, reselect the position of the maximum acceleration and the length of the contraction section, and repeat step S4. Figure 5 As shown, in this embodiment, the measurement target of the vortex flowmeter is first determined according to the project requirements, and the type, density, viscosity, etc. of the fluid are clarified. Secondly, appropriate assumptions are made about the flow conditions according to the environment, that is, the fluid is assumed to be an incompressible fluid (for most liquids and low-speed gases), and then the values ​​of n, L, and m are preliminarily determined, and the equation of the axial distribution curve of the acceleration of the designed new contraction section is calculated, and then the geometric shape of the vortex generator is set, and then the relationship between the vortex frequency, flow rate and frequency is calculated, and finally the results are verified and optimized. If the expected engineering accuracy and requirements are not met, the values ​​of n, L, and m need to be redesigned.

[0135] This embodiment combines the contraction section component, that is, combines the linear contraction structure with the curved contraction structure, to reduce the manufacturing complexity and cost while reducing the sharp change of flow velocity during the contraction process, to ensure that the fluid can enter the measuring section component smoothly and without eddy currents, and solves and obtains the structural design parameters of the vortex flow sensor based on the acceleration axial distribution curve equation to confirm the structural contraction curve equation and then obtain the fluid flow velocity of the vortex flow sensor; based on the constructed structural evaluation index model, the contraction ratio, contraction section length and maximum fluid acceleration position that meet the preset expected indicators are confirmed according to the fluid flow velocity and the structural design parameters, so as to realize the flexible optimization design of the vortex flow sensor structure according to different occasions, thereby providing more accurate and stable measurement results under various complex working conditions.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing the structure of a vortex flow sensor, characterized in that: The specific steps include: S1: Construct the simulation structure model of vortex flow sensor; The simulation structure model includes a stabilizing segment component for rectifying the fluid, a combined contraction segment component for optimizing the flow velocity distribution of the fluid output by the stabilizing segment component and reducing the turbulence to obtain a fluid vortex signal, and a measuring segment component for detecting the fluid vortex signal. The combined contraction section component includes a linear contraction structure and a curved contraction structure; S2: Construct the acceleration axial distribution curve equation of the vortex flow sensor; S3: Based on the maximum acceleration limit value of the fluid in the vortex flow sensor, the maximum acceleration position of the curve contraction structure is randomly set, and the length of the combined contraction section component is set based on the size of the vortex flow sensor; S4: Based on the acceleration axial distribution curve equation, according to the location of the maximum acceleration and the length of the combined contraction section component, solve and obtain the structural design parameters of the vortex flow sensor, and confirm the structural contraction curve equation based on the structural design parameters; S5: Obtaining the fluid flow velocity of the vortex flow sensor according to the structural contraction curve equation; S6: Based on the constructed structural evaluation index model, confirm whether the preset expected indicators are met according to the fluid flow rate and structural design parameters; If the preset expected index is met, the structural contraction ratio of the vortex flow sensor is confirmed based on the fluid flow rate, and the confirmed structural contraction ratio, the position of the maximum acceleration of the curve contraction structure set at this time, and the length of the combined contraction section component are the results of the geometric structure optimization design of the vortex flow sensor; Otherwise, the position of the maximum acceleration and the length of the contraction section are reselected, and step S4 is repeated.

2. A vortex flow sensor structure optimization design method according to claim 1, characterized in that: The method for constructing the acceleration axial distribution curve equation of the vortex flow sensor structure in S2 specifically includes the following steps S21: obtaining the axial acceleration function and function restriction condition of the vortex flow sensor structure; The axial acceleration function includes the acceleration axial distribution function of the linear contraction section structure and the acceleration axial distribution function of the curved contraction section structure, and its expression is l1=a1x(1) <h2 style=";text-align:left;direction:ltr">l2 = a2x<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +b2x+c2(2) Where: l1 represents the acceleration of the linear contraction section; l2 represents the acceleration of the curved contraction section; a1, a2, b2, c2 represent the constant term coefficients of the axial acceleration function; x represents the distance from the section to the entrance of the combined contraction section; The expression of the function restriction condition is a1>0, a2<0; b2>0(3) x2=L(7) Where: x1, x2 represent the analytical solution of the acceleration axial distribution function of the contraction section of the curve; L represents the length of the combined contraction section; m represents the position where the acceleration reaches the maximum; S22: Simplify equation (4) to get the expression: Combining equation (8) with equation (6), we can get equation (9): S23: Combining equations (9), (6) and (7), we can obtain equation (10): And further combining equation (10) and equation (6) we can get equation (11): S24: Combining equation (11) with equation (10), we can get equation (12): And further combining equation (12) and equation (8) we can get equation (13): S25: According to step S24, the acceleration axial distribution curve equation of the vortex flow sensor structure is constructed, and its expression is:

3. A vortex flow sensor structure optimization design method according to claim 2, characterized in that: The S4 specifically includes the following steps S41: Obtain the one-dimensional fluid acceleration equation for the fluid input into the vortex flow sensor, which is expressed as follows: And simplify it to obtain formula (16) as Kadx = udu (16) Where: u represents the fluid flow rate; K represents the structural design parameters of the vortex flow sensor to be solved; a represents the fluid acceleration; S42: Substitute equation (14) into equation (16) for piecewise integration operation to solve and obtain the fluid flow field, which is expressed as In the range of x≤m, when x=m, u=u1, and the fluid flow field is obtained as: u1 2 =u0 2 +Km 2 (L-m) 2 (17) In the range of m<x≤L, when x=L, u=u2, the fluid flow field is obtained as: S43: Combine equation (17) and equation (18) to obtain the structural design parameters of the vortex flow sensor, which is expressed as The obtained structural design parameters of the vortex flow sensor are substituted into equations (17) and (18) to obtain the structural contraction curve equation of the vortex flow sensor.

4. A vortex flow sensor structure optimization design method according to claim 3, characterized in that: In S6, based on the constructed structural evaluation index model, it is confirmed whether the preset expected index is met according to the fluid flow rate and the structural design parameters, specifically: Based on the constructed structural evaluation index model, confirm whether the preset expected indicators are met according to the fluid flow rate and structural design parameters; And the preset expected index includes a preset vortex frequency threshold and a preset volume flow threshold; If the preset expected index is met, the structural contraction ratio of the vortex flow sensor is confirmed based on the fluid flow rate, and the confirmed structural contraction ratio, the position of the maximum acceleration of the curve contraction structure set at this time, and the length of the combined contraction section component are the results of the geometric structure optimization design of the vortex flow sensor; And the expression for confirming the structural contraction ratio of the vortex flow sensor is u0S0=u1S1=u2S2=n(20) Wherein: n represents the contraction ratio; u0 represents the velocity of the fluid flowing into the combined contraction section component; S0 represents the cross-sectional area of ​​the fluid flowing into the combined contraction section component; u2 represents the velocity of the fluid flowing out of the combined contraction section component; S2 represents the cross-sectional area of ​​the fluid flowing out of the combined contraction section component; u1 represents the velocity at the point m where the fluid acceleration is the largest on the contraction section component; S1 represents the cross-sectional area at the point m where the fluid acceleration is the largest on the contraction section component; Otherwise, the position of the maximum acceleration and the length of the contraction section are reselected, and step S4 is repeated.

5. A vortex flow sensor structure optimization design method according to claim 4, characterized in that: The structural evaluation index model constructed in S6 is expressed as follows: Where: f represents the vortex frequency; U represents the fluid flow rate, which is the output of the structural contraction curve equation of the vortex flow sensor; D represents the characteristic size of the vortex generator, i.e., the combined contraction section component; S t represents the Strouhal number and is a constant; Q represents the volume flow rate of the vortex flow sensor; K represents the structural design parameters of the vortex flow sensor.

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