Optimization design method of bidirectional flow wide-range venturi flowmeter

Abstract

The invention discloses an optimization design method of a bidirectional flow wide-range Venturi flowmeter. The optimization design method comprises the following steps: (1) preliminary design; (2) simulation optimization; (3) manufacturing the venturi tube for the test: designing and manufacturing the venturi tube for the test, taking the geometric dimensions of the inner holes of the inlet section, the contraction section, the throat section, the diffusion section and the outlet section of the venturi tube obtained through simulation optimization as initial data of the geometric dimensions of the inner holes of the venturi tube for the test, and arranging a geometric dimension adjusting device on the venturi tube for the test, the Venturi tube for the test becomes a size-adjustable Venturi tube for the test; the size-adjustable test venturi tube is also provided with a geometric dimension on-line measurement module for dynamically measuring the geometric dimensions of the inner holes of the contraction section, the throat section and the diffusion section of the venturi tube during the test; (4) test verification; and (5) dynamic adjustment. The two-way flow wide-range high-precision measurement of the Venturi flow meter is realized.

Description

Technical Field

[0001] The invention relates to the technical field of venturi flowmeters, and in particular to an optimization design method for a bidirectional wide-range venturi flowmeter. Background Art

[0002] The Venturi Flow Meter is a differential pressure flow measurement device designed based on the Venturi effect. It calculates the flow rate of the fluid by measuring the pressure difference generated when the fluid passes through a gradually contracting and then expanding pipe section. The Venturi flow meter is widely used in industrial and laboratory environments for the flow measurement of liquids and gases due to its simple structure, high accuracy, and low pressure loss.

[0003] Conventional Venturi flowmeters include a Venturi tube consisting of an inlet section, a contraction section, a throat section, a diffusion section, and an outlet section; the inner holes of the contraction section and the diffusion section are both conical holes. The typical Venturi flow tube structure is a large-scale high-precision main water supply Venturi tube assembly (publication number CN111750938A) that our company has developed and authorized in the early stage; it reduces the disturbance of the fluid under high temperature and high pressure by setting a flow straightening plate and an upstream straight pipe at the front end of the Venturi tube section, and setting a downstream straight pipe at the rear end of the Venturi tube section, so that the fluid forms a more stable flow state on both sides of the Venturi tube section, thereby improving the measurement accuracy of the large Venturi tube flowmeter. However, this large Venturi tube flowmeter is specially designed for unidirectional flow of fluid, and cannot realize measurement under bidirectional flow of fluid (that is, sometimes forward flow and sometimes reverse flow).

[0004] In order to achieve bidirectional measurement, the conical hole of the contraction section and the conical hole of the diffusion section of the venturi tube can be made into a symmetrical structure. However, the experimental structure shows that the symmetrical structure of the venturi tube improved on the basis of the conventional venturi flowmeter is limited by the measurement accuracy and its range is relatively narrow.

[0005] In addition, the large-scale high-precision main water supply Venturi tube assembly also optimizes the inner diameter size of the closing cylinder section (throat cylinder section) of the product Venturi tube section by setting the technology of debugging the Venturi tube section, so as to improve the performance of the Venturi tube flowmeter. However, the technology of debugging the Venturi tube section still has the following shortcomings: One is to use the film sticking method to obtain the experimental size of the inner hole of the new closed cylindrical section (throat cylindrical section), but the film sticking method requires the debugging Venturi tube section to be disassembled, and the operation is more troublesome and time-consuming; in addition, the performance and roughness of the membrane wall are quite different from the performance and roughness of the metal tube wall of the actual product Venturi tube, and after the film is stuck, the two ends of the membrane hole may have defects such as uneven connection and step difference, which will affect the accuracy of the test.

[0006] Second, a liquid plastic expansion ring is used to adjust the inner hole diameter of the necking cylinder section (throat cylinder section). Its adjustment amount is small. If the adjustment amount is increased, a large non-linear deformation error (a drum-shaped error where the middle bulges towards the inner hole) will occur. There is a large difference between this and the straight hole shape in the simulation design. Applying this non-linear shape to the actual product, the Venturi tube may cause processing difficulties. Moreover, if the inner hole in the throat section adopts a special non-linear shape, it may also affect the stability of the fluid, which is not conducive to improving the performance of the actual product, the Venturi tube.

[0007] Third, the optimized inner hole size of the Venturi tube section after debugging cannot be measured online. The debugged Venturi tube section needs to be removed from the test bench to be measured. However, since the deformation shape and size of the liquid plastic expansion ring are the result of the combined action of the pressure of the internal liquid plastic and the fluid pressure inside the debugged Venturi tube section to form an equilibrium, when the debugged Venturi tube section is removed, the balance of the fluid pressure is lost. Therefore, the inner hole size of the debugged Venturi tube obtained will be different from the size during the actual test, which has a greater impact on the test accuracy. Summary of the Invention

[0008] To solve the above problems, the present invention proposes an optimized design method for a two-way flow wide-range Venturi flowmeter, aiming to overcome the above deficiencies of the existing Venturi flowmeter and achieve high-precision measurement of the two-way flow wide range of the Venturi flowmeter. The specific technical solutions are as follows: A two-way flow wide-range Venturi flowmeter includes a Venturi tube and flange connection components provided at the left and right ends of the Venturi tube. The Venturi tube includes an inlet section, a contraction section, a throat section, a diffusion section, and an outlet section that are sequentially arranged and connected from left to right. Among them, the contraction section is a double-taper contraction section, the diffusion section is a double-taper diffusion section, and the inlet section, the double-taper contraction section, the double-taper diffusion section, and the outlet section are symmetrically arranged at both ends of the throat section with respect to the throat section; on the outer circumference of the throat section of the Venturi tube, a plurality of throat section pressure measurement holes communicating with the fluid through holes of the throat section are arranged circumferentially. On the outer circumference of the inlet section of the Venturi tube, a plurality of inlet section pressure measurement holes communicating with the fluid through holes of the inlet section are arranged circumferentially. On the outer circumference of the outlet section of the Venturi tube, a plurality of outlet section pressure measurement holes communicating with the fluid through holes of the outlet section are arranged circumferentially; on the outer circumference of the Venturi tube, a first pressure measurement ring, a second pressure measurement ring, and a third pressure measurement ring with inner annular grooves are also respectively provided. The inlet section pressure measurement holes communicate with the inner annular groove of the first pressure measurement ring, the throat section pressure measurement holes communicate with the inner annular groove of the second pressure measurement ring, and the outlet section pressure measurement holes communicate with the inner annular groove of the third pressure measurement ring; pressure taking pipes communicating with the inner annular grooves are respectively led out from the first pressure measurement ring, the second pressure measurement ring, and the third pressure measurement ring.

[0009] Preferably, the number of the pressure measuring holes in the inlet section, the throat section and the outlet section is four each, and they are evenly distributed along the outer circumference of the Venturi tube.

[0010] Preferably, the first pressure measuring ring, the second pressure measuring ring and the third pressure measuring ring are all sleeved on the outer circle of the Venturi tube, and the inner ring grooves are closed by welding.

[0011] In the present invention, the fluid through holes in the inlet section and the throat section are straight holes, and the fluid through hole in the double-taper contraction section includes a large-taper conical hole with a relatively large taper and a small-taper conical hole with a relatively small taper arranged in sequence from left to right; the fluid passage in the double-taper diffusion section includes a small-taper conical hole with a relatively small taper and a large-taper conical hole with a relatively large taper arranged in sequence from left to right.

[0012] Preferably, the cone angle of the large-taper conical hole is 80°±5°, and the cone angle of the small-taper conical hole is 14°±2°.

[0013] Preferably, the ratio of the aperture of the straight hole in the inlet section to the aperture of the straight hole in the throat section is 1.75:1 to 2.15:1.

[0014] Preferably, the pressure measuring hole in the inlet section is exactly located at the edge position of the adjacent junction of the inlet section and the contraction section on the outer circle of the inlet section, the pressure measuring hole in the throat section is located at the middle position of the outer circle of the throat section, and the pressure measuring hole in the outlet section is exactly located at the edge position of the adjacent junction of the outlet section and the diffusion section on the outer circle of the outlet section.

[0015] In the present invention, the flange connection assembly includes a pair of connection flanges respectively arranged at the left and right ends of the Venturi tube and clamped and butted by connection screws, and one of the pair of connection flanges is welded to the end of the Venturi tube.

[0016] Preferably, an end face ring groove is formed between the clamping surfaces of the pair of connection flanges, and an annular sealing ring is arranged in the end face ring groove.

[0017] Preferably, the geometric dimensions of the inlet section, the contraction section, the throat section, the diffusion section and the outlet section of the Venturi tube are the geometric dimensions obtained through simulation optimization.

[0018] Preferably, the geometric dimensions of the inlet section, the contraction section, the throat section, the diffusion section and the outlet section of the Venturi tube are also verified by tests after simulation optimization, and the geometric dimensions of the contraction section, the throat section and the diffusion section of the Venturi tube are further optimized through test verification.

[0019] An optimization design method for a two-way flow wide-range Venturi flowmeter includes the following steps: (1)Preliminary design: Design the basic structure of the Venturi tube. The basic structure of the Venturi tube includes an inlet section, a contraction section, a throat section, a diffuser section, and an outlet section. Among them, the contraction section is a double-taper contraction section, the diffuser section is a double-taper diffuser section, and the inlet section, the double-taper contraction section, the double-taper diffuser section, and the outlet section are symmetrically arranged at both ends of the throat section with respect to the throat section; (2)Simulation optimization: Establish a simulation model of a two-way flow wide-range Venturi flowmeter aiming at improving the measurement accuracy under a wide range. Simulate and optimize the inner hole geometric dimensions of the inlet section, contraction section, throat section, diffuser section, and outlet section of the Venturi tube to obtain the simulation optimization dimension data of the Venturi tube; (3)Fabrication of the test Venturi tube: According to the simulation optimization dimension data of the Venturi tube, design and fabricate a test Venturi tube. Take the inner hole geometric dimensions of the inlet section, contraction section, throat section, diffuser section, and outlet section of the Venturi tube obtained by simulation optimization as the initial data of the inner hole geometric dimensions of the test Venturi tube, and set a geometric dimension adjusting device on the test Venturi tube, so that the test Venturi tube becomes a dimension-adjustable test Venturi tube whose inner hole geometric dimensions of the contraction section, throat section, and diffuser section are synchronously adjustable; A geometric dimension on-line measurement module for dynamically measuring the inner hole geometric dimensions of the contraction section, throat section, and diffuser section of the Venturi tube during the test is also provided on the dimension-adjustable test Venturi tube; (4)Test verification: Install the dimension-adjustable test Venturi tube on the Venturi tube test bench for performance testing and verification to obtain the actual flow measurement accuracy data under a wide range; (5)Dynamic adjustment: Through the geometric dimension adjusting device on the test Venturi tube, synchronously adjust the geometric dimensions of the contraction section, throat section, and diffuser section of the test Venturi tube on-line, and test and verify its actual flow measurement accuracy under a wide range after the dimension adjustment; Through continuous adjustments for several times, obtain the optimal geometric dimensions of the contraction section, throat section, and diffuser section of the test Venturi tube with the optimal actual flow measurement accuracy under a wide range; The optimal geometric dimensions are measured by the geometric dimension on-line measurement module through an optoelectronic distance measuring sensor; (6)Final design: Take the optimal geometric dimensions of the test Venturi tube obtained in the dynamic adjustment in step (5) as the final design dimensions of the Venturi tube of the two-way flow wide-range Venturi flowmeter.

[0020] Among them, the actual flow measurement accuracy of the two-way flow wide-range Venturi flowmeter is obtained by comparing with a standard flowmeter on the test bench.

[0021] Preferably, a plurality of high-precision narrow-range Venturi flowmeters are arranged on the test bench as standard flowmeters with different ranges, and the series combination of the plurality of narrow-range Venturi flowmeters covers the wide-range measurement range of the bidirectional flow wide-range Venturi flowmeter.

[0022] In the present invention, the size-adjustable test Venturi tube includes a circular straight cylinder and a composite-shaped thin-walled tube connected to the middle position of the inner hole wall of the circular straight cylinder. The composite-shaped thin-walled tube includes a contraction-section thin-walled tube for forming the inner hole of the contraction section, a throat-section thin-walled tube for forming the inner hole of the throat section, and a diffuser-section thin-walled tube for forming the inner hole of the diffuser section, which are arranged and connected in sequence from left to right; the contraction-section thin-walled tube is formed by connecting a large-taper thin-walled tube with a relatively large taper and a small-taper thin-walled tube with a relatively small taper arranged in sequence from left to right; the diffuser-section thin-walled tube is formed by connecting a small-taper thin-walled tube with a relatively small taper and a large-taper thin-walled tube with a relatively large taper arranged in sequence from left to right; a sealed annular cavity is formed between the composite-shaped thin-walled tube and the inner hole of the circular straight cylinder. The geometric dimension adjustment device of the size-adjustable test Venturi tube includes a vacuum suction port arranged on the circular straight cylinder and communicating with the annular cavity, and a vacuum pumping system connected to the vacuum suction port through a vacuum pumping pipeline; a vacuum degree adjustment device for adjusting the internal vacuum degree of the annular cavity is arranged on the vacuum pumping pipeline.

[0023] Preferably, the number of the vacuum suction ports is multiple and they are evenly distributed on the outer circle of the middle section of the test Venturi tube.

[0024] Preferably, the connection between the two ends of the wall of the composite-shaped thin-walled tube and the inner hole wall of the circular straight cylinder is welded.

[0025] In order to enable the composite-shaped thin-walled tube to obtain a large elastic tensile deformation amount when being stretched outward under the action of vacuum, the composite-shaped thin-walled tube can be a composite-shaped thin-walled tube made of an elastic metal material, so that different test conditions can be verified repeatedly. Of course, a composite-shaped thin-walled tube made of a non-elastic metal material with good elongation performance can also be used. The test can start from the smallest tensile deformation until a large tensile deformation. For such a test, each size can only be tested once (because the composite-shaped thin-walled tube no longer shrinks and resets after plastic deformation caused by stretching). Its advantage is that a larger diameter change range can be obtained, so as to obtain more test data.

[0026] Preferably, the vacuum degree adjusting device includes a first electric regulating valve connected in series to the vacuum suction pipeline for cutting off or connecting the vacuum suction pipeline, a vacuum pressure gauge connected transversely to the vacuum suction pipeline for measuring the vacuum degree inside the annular cavity, and a second electric regulating valve for air intake connected transversely to the vacuum suction pipeline for adjusting the vacuum degree inside the annular cavity.

[0027] In the present invention, the geometric dimension online measurement module comprises a plurality of photoelectric distance measuring sensors which are arranged on the circular straight cylinder at intervals along the axial direction.

[0028] Preferably, a plurality of photoelectric distance measuring sensors arranged at intervals along the circumferential direction are provided on the same circumference of the circular straight cylinder.

[0029] Preferably, based on the inner hole geometric dimensions of the inlet section, contraction section, throat section, diffusion section and outlet section of the Venturi tube obtained by simulation optimization, when manufacturing the test Venturi tube, based on the inner hole geometric dimensions of the contraction section, throat section and diffusion section of the Venturi tube obtained by simulation optimization, the inner hole dimension D of the throat section is appropriately reduced by a predetermined value e; during the test, the test verification is started from the smallest throat inner hole geometric dimension (De), and the composite-shaped thin-walled tube is gradually stretched in the longitudinal direction by gradually increasing the vacuum degree inside the annular cavity, so that the inner hole geometric dimensions of the contraction section, throat section and diffusion section of the test Venturi tube are gradually expanded until the largest throat section inner hole geometric dimension (D+e).

[0030] As a further improvement, the optimization design method of a bidirectional flow width range Venturi flowmeter of the present invention also includes an aperture linear smoothing processing module for compensating for the nonlinear deformation of the composite shape thin-walled tube of the test Venturi tube under the vacuum action inside the annular cavity; the aperture linear smoothing processing module includes a breathable elastic thermal expansion foamed porous material filled inside the annular cavity, and a number of power-adjustable annular low-temperature heating plates arranged along the axial direction are pre-embedded inside the breathable elastic thermal expansion foamed porous material, and the power-adjustable annular low-temperature heating plates are connected to the temperature control system.

[0031] Preferably, the air-permeable elastic thermal expansion foam porous material is a silicone rubber air-permeable elastic thermal expansion foam porous material containing 10-30% aluminum powder.

[0032] Preferably, the silicone rubber breathable elastic thermal expansion foamed porous material is formed by mixing aluminum powder, a foaming agent, a vulcanizing agent and a silicone rubber matrix, filling the mixture into the annular cavity of the venturi tube, and decomposing the foaming agent at a certain temperature and pressure to trigger a vulcanization reaction.

[0033] In order to realize the filling of the foaming material, a filling port can be opened on the circular straight cylinder, and a sealing plug can be arranged on the filling port. The sealing plug can be closed by welding after the filling is completed to enhance the sealing performance.

[0034] Preferably, in order to prevent deformation of the composite-shaped thin-walled sleeve during the foaming process, a pair of anti-deformation mandrels that are compatible with the inner hole of the composite-shaped thin-walled tube (including the tapered hole) can be installed at the inner hole of the composite-shaped thin-walled tube of the experimental Venturi tube during the foaming process (the anti-deformation mandrels are respectively installed from both ends).

[0035] In the present invention, a detection avoidance hole for the detection light of the photoelectric ranging sensor to pass through is provided on the breathable elastic thermal expansion foam porous material; a metal corrugated telescopic tube for forming a pressure measuring hole in the throat section is connected between the circular straight cylinder and the throat section thin-walled tube.

[0036] Preferably, during the dynamic adjustment of step (5), the nonlinear deformation (drum shape or concave shape) of the thin-walled tube of the contraction section, throat section and diffusion section of the experimental venturi tube under the vacuum inside the annular cavity is corrected as follows by an aperture linear smoothing processing module; S1. Measurement: The aperture size data of the contraction section, throat section, and diffusion section of the thin-walled tube of the test venturi tube are measured online by a photoelectric distance measuring sensor at several locations in the axial direction. S2. Calculation: Calculate the nonlinear deformation error of the contraction section thin-walled tube (including the large-taper thin-walled tube and the small-taper thin-walled tube), the nonlinear deformation error of the throat section thin-walled tube, and the nonlinear deformation error of the diffusion section thin-walled tube (including the large-taper thin-walled tube and the small-taper thin-walled tube) respectively; S3. Correction: According to the nonlinear deformation error data of different parts on the composite-shaped thin-walled sleeve, the temperature control system of the aperture linear smoothing processing module is turned on, and different heating powers are applied to different positions of the breathable elastic thermal expansion foamed porous material through the power-adjustable annular low-temperature heating sheets pre-buried in different parts inside the breathable elastic thermal expansion foamed porous material, so that the breathable elastic thermal expansion foamed porous material forms a gradient temperature difference, thereby obtaining different elastic deformation compensation amounts at different parts. The elastic deformation compensation amount acts on the composite-shaped thin-walled sleeve, so that the nonlinear deformation of the thin-walled tubes of the contraction section, throat section and diffusion section of the experimental Venturi tube is corrected.

[0037] The beneficial effects of the present invention are: First, an optimized design method for a two-way flow wide-range Venturi flowmeter according to the present invention. The inlet section, contraction section, throat section, diffuser section, and outlet section of the Venturi tube are arranged in sequence and symmetrically arranged on both sides with the throat section as the center, enabling two-way measurement of flow rate. Moreover, both the contraction section and the diffuser section adopt a double-taper structure, which is beneficial to improving the stability of the fluid and realizing two-way flow wide-range measurement.

[0038] Second, an optimized design method for a two-way flow wide-range Venturi flowmeter according to the present invention. The debug Venturi tube adopted uses the principle of vacuum stretching deformation to achieve variable diameter design. Its deformation range is large, which is beneficial to finding optimization points within a relatively wide size range and improving the performance of the Venturi flowmeter.

[0039] Third, an optimized design method for a two-way flow wide-range Venturi flowmeter according to the present invention. The variable diameter operation of the debug Venturi tube can be carried out online dynamically without disassembly. The internal hole size measurement after variable diameter is dynamically measured by an optoelectronic ranging sensor (measuring a composite-shaped thin-walled tube and obtaining the result through conversion based on the wall thickness), overcoming the drawback of size distortion caused by the need to disassemble for measurement after experiments in the prior art (CN111750938A, a large-scale high-precision main feed water Venturi tube assembly).

[0040] Fourth, an optimized design method for a two-way flow wide-range Venturi flowmeter according to the present invention. An aperture linear smoothing processing module is provided on the debug Venturi tube. By controlling the heating power of the power-adjustable annular low-temperature heat tracing sheets at different positions, a temperature gradient can be formed inside the debug Venturi tube, enabling the thermal expansion amounts of the breathable elastic thermal expansion foamed porous material inside the annular cavity to be different at each location. The breathable elastic thermal expansion foamed porous material's thermal expansion is used to reversely offset or reduce the non-linear deformation error during the vacuum stretching deformation of the composite-shaped thin-walled tube, playing a role in smoothing and correcting the conical holes and straight holes on the composite-shaped thin-walled tube, thereby realizing the optimal design of the two-way flow wide-range Venturi flowmeter. Description of the Drawings

[0041] Figure 1 is a schematic structural diagram of a two-way flow wide-range Venturi flowmeter in the present invention; Figure 2 is a schematic structural diagram of the test Venturi tube in the present invention; Figure 3 is Figure 1 and Figure 2 is a schematic structural diagram of the pressure measurement ring in

[0042] In the figure: 100, Venturi tube; 101, Flange connection assembly; 102, Inlet section; 103, Converging section; 104, Throat section; 105, Diverging section; 106, Outlet section; 107, Pressure measurement hole in the throat section; 108, Pressure measurement hole in the inlet section; 109, Pressure measurement hole in the outlet section; 110, Inner annular groove; 111, First pressure measurement ring; 112, Second pressure measurement ring; 113, Third pressure measurement ring; 114, Pressure tapping pipe; 115, Large taper conical hole; 116, Small taper conical hole; 117, Connecting screw; 118, Connecting flange; 119, Annular sealing ring; 200, Venturi tube for experiment; 201, Circular straight cylinder; 202, Composite shape thin-walled tube; 203, Converging section thin-walled tube; 204, Throat section thin-walled tube; 205, Diverging section thin-walled tube; 206, Large taper thin-walled tube; 207, Small taper thin-walled tube; 208, Annular cavity; 209, Vacuum suction port; 210, Vacuum suction pipeline; 211, Vacuum pumping system; 212, Vacuum degree regulating device; 213, First electric control valve; 214, Vacuum pressure gauge; 215, Second electric control valve; 216, Photoelectric distance measurement sensor; 217, Aperture linear smoothing processing module; 218, Breathable elastic thermal expansion foamed porous material; 219, Power adjustable annular low-temperature heat tracing sheet; 220, Temperature control system; 221, Detection avoidance hole; 222, Metal bellows expansion joint. Specific implementation mode

[0043] The following combines the drawings and embodiments to further describe the specific implementation mode of the present invention. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0044] Embodiment 1: As Figures 1 to 3The following shows an embodiment of a two-way flow wide-range Venturi flowmeter of the present invention, which includes a Venturi tube 100 and flange connection components 101 provided at the left and right ends of the Venturi tube 100. The Venturi tube 100 includes an inlet section 102, a contraction section 103, a throat section 104, a diffusion section 105, and an outlet section 106 that are sequentially arranged and connected from left to right. Among them, the contraction section 103 is a double-taper contraction section, the diffusion section 105 is a double-taper diffusion section, and the inlet section 102, the double-taper contraction section 103, the double-taper diffusion section 105, and the outlet section 106 are symmetrically arranged at both ends of the throat section 104 with respect to the throat section 104; on the outer circumference of the throat section 104 of the Venturi tube 100, a plurality of throat section pressure measurement holes 107 communicating with the fluid through holes of the throat section 104 are arranged circumferentially. On the outer circumference of the inlet section 102 of the Venturi tube 100, a plurality of inlet section pressure measurement holes 108 communicating with the fluid through holes of the inlet section 102 are arranged circumferentially. On the outer circumference of the outlet section 106 of the Venturi tube 100, a plurality of outlet section pressure measurement holes 109 communicating with the fluid through holes of the outlet section 106 are arranged circumferentially; on the outer circumference of the Venturi tube 100, a first pressure measurement ring 111, a second pressure measurement ring 112, and a third pressure measurement ring 113 with inner ring grooves 110 are respectively provided. The inlet section pressure measurement holes 108 communicate with the inner ring groove 110 of the first pressure measurement ring 111, the throat section pressure measurement holes 107 communicate with the inner ring groove 110 of the second pressure measurement ring 112, and the outlet section pressure measurement holes 109 communicate with the inner ring groove 110 of the third pressure measurement ring 113; pressure tapping tubes 114 communicating with the inner ring groove 110 are respectively led out from the first pressure measurement ring 111, the second pressure measurement ring 112, and the third pressure measurement ring 113.

[0045] Preferably, the number of the inlet section pressure measurement holes 108, the throat section pressure measurement holes 107, and the outlet section pressure measurement holes 109 is four each, and they are evenly distributed along the outer circumference of the Venturi tube 1000.

[0046] Preferably, the first pressure measurement ring 111, the second pressure measurement ring 112, and the third pressure measurement ring 113 are all sleeved on the outer circumference of the Venturi tube 100, and the inner ring groove 110 is hermetically arranged by welding.

[0047] In the present invention, the fluid through holes of the inlet section 102 and the throat section 104 are both straight holes. The fluid through hole of the double-taper contraction section 103 includes a large-taper conical hole 115 with a relatively large taper and a small-taper conical hole 116 with a relatively small taper that are sequentially arranged from left to right; the fluid passage of the double-taper diffusion section 105 includes a small-taper conical hole 116 with a relatively small taper and a large-taper conical hole 115 with a relatively large taper that are sequentially arranged from left to right.

[0048] Preferably, the cone angle of the large-taper cone hole 115 is 80° ± 5°, and the cone angle of the small-taper cone hole 116 is 14° ± 2°.

[0049] Preferably, the ratio of the aperture of the straight hole of the inlet section 102 to that of the straight hole of the throat section 104 is 1.75:1 to 2.15:1.

[0050] Preferably, the pressure measurement hole 108 of the inlet section is exactly located at the edge position of the outer circle of the inlet section 102 where the inlet section 102 is adjacent to the contraction section 103, the pressure measurement hole 107 of the throat section is located at the middle position of the outer circle of the throat section 104, and the pressure measurement hole 109 of the outlet section is exactly located at the edge position of the outer circle of the outlet section 106 where the outlet section 106 is adjacent to the diffusion section 105.

[0051] In the present invention, the flange connection assembly 101 includes a pair of connection flanges 118 respectively arranged at the left and right ends of the venturi tube 100 and clamped and docked by connection screws 117, and one of the pair of connection flanges 118 is welded to the end of the venturi tube 100.

[0052] Preferably, an end face ring groove is provided between the clamping surfaces of the pair of connection flanges 118, and an annular sealing ring 119 is arranged in the end face ring groove.

[0053] Preferably, the geometric dimensions of the inlet section 102, contraction section 103, throat section 104, diffusion section 105, and outlet section 106 of the venturi tube 100 are geometric dimensions obtained through simulation optimization.

[0054] Preferably, the geometric dimensions of the inlet section 102, contraction section 103, throat section 104, diffusion section 105, and outlet section 106 of the venturi tube 100 are also experimentally verified after simulation optimization, and the geometric dimensions of the contraction section 103, throat section 104, and diffusion section 105 of the venturi tube 100 are further optimized through experimental verification.

[0055] Embodiment 2: An optimization design method for a two-way flow wide-range venturi flowmeter includes the following steps: (1) Preliminary design: Design the basic structure of the venturi tube 100. The basic structure of the venturi tube 100 includes an inlet section 102, a contraction section 103, a throat section 104, a diffusion section 105, and an outlet section 106. Among them, the contraction section 103 is a double-taper contraction section, the diffusion section 105 is a double-taper diffusion section, and the inlet section 102, the double-taper contraction section 103, the double-taper diffusion section 105, and the outlet section 106 are symmetrically arranged at both ends of the throat section 105 with respect to the throat section 105. (2) Simulation optimization: Establish a simulation model of a two-way flow wide-range Venturi flowmeter aiming at improving measurement accuracy under a wide range, and conduct simulation optimization on the inner hole geometric dimensions of the inlet section 102, contraction section 103, throat section 104, diffusion section 105 and outlet section 106 of the Venturi tube 100 to obtain the simulation-optimized dimension data of the Venturi tube 100; (3) Fabrication of the test Venturi tube: According to the simulation-optimized dimension data of the Venturi tube 100, design and fabricate a test Venturi tube 200. Take the inner hole geometric dimensions of the inlet section 102, contraction section 103, throat section 104, diffusion section 105 and outlet section 106 of the Venturi tube 100 obtained by simulation optimization as the initial data of the inner hole geometric dimensions of the test Venturi tube 200, and set a geometric dimension adjustment device on the test Venturi tube 200, so that the test Venturi tube 200 becomes a dimension-adjustable test Venturi tube whose inner hole geometric dimensions of the contraction section 103, throat section 104 and diffusion section 105 are synchronously adjustable; A geometric dimension on-line measurement module for dynamically measuring the inner hole geometric dimensions of the contraction section 103, throat section 104 and diffusion section 105 of the Venturi tube during the test is also provided on the dimension-adjustable test Venturi tube; (4) Test verification: Install the dimension-adjustable test Venturi tube 200 on a Venturi tube test bench for performance testing and verification to obtain the actual flow measurement accuracy data under a wide range; (5) Dynamic adjustment: Through the geometric dimension adjustment device on the test Venturi tube 200, synchronously adjust the geometric dimensions of the contraction section 103, throat section 104 and diffusion section 105 of the test Venturi tube 200 on-line, and verify the actual flow measurement accuracy under a wide range after the dimension adjustment; Through continuous adjustment several times, obtain the optimal geometric dimensions of the contraction section 103, throat section 104 and diffusion section 105 of the test Venturi tube 200 with the optimal actual flow measurement accuracy under a wide range; The optimal geometric dimensions are measured by the geometric dimension on-line measurement module through the photoelectric distance measurement sensor 216; (6) Final design: Take the optimal geometric dimensions of the test Venturi tube 200 obtained in the dynamic adjustment in step (5) as the final design dimensions of the Venturi tube 100 of the two-way flow wide-range Venturi flowmeter.

[0056] Among them, the actual flow measurement accuracy of the two-way flow wide-range Venturi flowmeter is obtained by comparing with a standard flowmeter on the test bench.

[0057] Preferably, a plurality of high-precision narrow-range Venturi flowmeters are provided on the test bench as standard flowmeters for different ranges, and the series combination of the plurality of narrow-range Venturi flowmeters covers the wide-range measurement range of the two-way flow wide-range Venturi flowmeter.

[0058] In the present invention, the size-adjustable venturi tube 200 for experiments includes a circular straight cylinder 201 and a composite-shaped thin-walled tube 202 connected to the middle position of the inner hole wall of the circular straight cylinder 201. The composite-shaped thin-walled tube 202 includes a contraction-section thin-walled tube 203, a throat-section thin-walled tube 204, and a diffuser-section thin-walled tube 205 that are sequentially arranged and connected from left to right and are used to form the inner hole of the contraction section 103, the inner hole of the throat section 104, and the inner hole of the diffuser section 105 respectively. The contraction-section thin-walled tube 203 is formed by connecting a large-taper thin-walled tube 206 with a relatively large taper and a small-taper thin-walled tube 207 with a relatively small taper that are sequentially arranged from left to right. The diffuser-section thin-walled tube 205 is formed by connecting a small-taper thin-walled tube 207 with a relatively small taper and a large-taper thin-walled tube 206 with a relatively large taper that are sequentially arranged from left to right. A sealed annular cavity 208 is formed between the composite-shaped thin-walled tube 202 and the inner hole of the circular straight cylinder 201. The geometric dimension adjustment device of the size-adjustable venturi tube for experiments includes a vacuum suction port 209 provided on the circular straight cylinder 201 and communicating with the annular cavity 208, and a vacuum pumping system 211 connected to the vacuum suction port 209 through a vacuum pumping pipeline 210. A vacuum degree adjustment device 212 for adjusting the internal vacuum degree of the annular cavity 208 is provided on the vacuum pumping pipeline 210.

[0059] Preferably, the number of the vacuum suction ports 209 is multiple and they are evenly distributed on the outer circle of the middle section of the venturi tube 200 for experiments.

[0060] Preferably, the connection between the two ends of the composite-shaped thin-walled tube 202 and the inner hole wall of the circular straight cylinder 201 is welded.

[0061] In order to enable the composite-shaped thin-walled tube 202 to obtain a large elastic tensile deformation amount when being stretched outward under vacuum, the composite-shaped thin-walled tube 202 can be a composite-shaped thin-walled tube 202 made of an elastic metal material, so that different test conditions can be verified repeatedly. Of course, a composite-shaped thin-walled tube 202 made of a non-elastic metal material with good elongation performance can also be used. The test can start from the smallest tensile deformation until a large tensile deformation. For such a test, each size can only be tested once (because the composite-shaped thin-walled tube 202 will no longer shrink and reset after plastic deformation due to stretching). Its advantage is that a larger diameter change range can be obtained, so as to obtain more test data.

[0062] Preferably, the vacuum degree adjusting device 212 includes a first electric regulating valve 213 connected in series to the vacuum suction pipeline 210 for cutting off or connecting the vacuum suction pipeline 210, a vacuum pressure gauge 214 connected transversely to the vacuum suction pipeline 210 for measuring the vacuum degree inside the annular cavity 208, and a second electric regulating valve 215 for air intake connected transversely to the vacuum suction pipeline 210 for adjusting the vacuum degree inside the annular cavity 208.

[0063] In the present invention, the geometric dimension online measurement module includes a plurality of photoelectric distance measuring sensors 216 arranged on the circular straight cylinder 201 at intervals along the axial direction.

[0064] Preferably, a plurality of photoelectric distance measuring sensors 216 are arranged on the same circumference of the circular straight cylinder 201 and are spaced apart from each other in the circumferential direction.

[0065] Preferably, based on the inner hole geometric dimensions of the inlet section 102, the contraction section 103, the throat section 104, the diffusion section 105 and the outlet section 106 of the Venturi tube 100 obtained by simulation optimization, when manufacturing the test Venturi tube 200, based on the inner hole geometric dimensions of the contraction section 103, the throat section 104 and the diffusion section 105 of the Venturi tube 100 obtained by simulation optimization, the inner hole dimension D of the throat section is appropriately reduced by a predetermined value e; during the test, the test verification is started from the smallest throat inner hole geometric dimension (De), and the composite-shaped thin-walled tube 202 is gradually stretched in the longitudinal direction by gradually increasing the vacuum degree inside the annular cavity 208, so that the inner hole geometric dimensions of the contraction section 103, the throat section 104 and the diffusion section 105 of the test Venturi tube 200 are gradually expanded until the largest throat section inner hole geometric dimension (D+e).

[0066] As a further improvement, the optimization design method of a bidirectional flow width range Venturi flowmeter of the present invention also includes an aperture linear smoothing processing module 217 for compensating for the nonlinear deformation of the composite shape thin-walled tube 202 of the test Venturi tube 200 under the vacuum action inside the annular cavity 208; the aperture linear smoothing processing module 217 includes a breathable elastic thermal expansion foamed porous material 218 filled inside the annular cavity 208, and a number of power-adjustable annular low-temperature heating plates 219 arranged along the axial direction are pre-buried inside the breathable elastic thermal expansion foamed porous material 218, and the power-adjustable annular low-temperature heating plates 219 are connected to the temperature control system 220.

[0067] Preferably, the breathable elastic thermal expansion foam porous material 218 is a breathable elastic thermal expansion foam porous material made of silicone rubber containing 10-30% aluminum powder.

[0068] Preferably, the silicone rubber breathable elastic thermal expansion foamed porous material is formed by mixing aluminum powder, a foaming agent, a vulcanizing agent with a silicone rubber matrix, filling the mixture into the annular cavity of the Venturi tube, and decomposing the foaming agent and triggering a vulcanization reaction under certain temperature and pressure conditions.

[0069] To achieve the filling of the foamed material, a filling port can be opened on the circular straight cylinder 201, and a sealing plug is provided on the filling port. The sealing plug can be closed by welding after the filling is completed to enhance the sealing performance.

[0070] Preferably, to prevent the deformation of the composite-shaped thin-walled sleeve 202 during the foaming process, a pair of anti-deformation mandrels (the anti-deformation mandrels are inserted from both ends) adapted to the inner hole (including the tapered hole) of the composite-shaped thin-walled tube 202 of the experimental Venturi tube 200 can be installed in the inner hole of the composite-shaped thin-walled tube 202 during the foaming process.

[0071] In the present invention, a detection avoidance hole 221 for the detection light of the optoelectronic distance measurement sensor 216 to pass through is provided on the breathable elastic thermal expansion foamed porous material 218; a metal bellows expansion joint 222 for forming the throat section pressure measurement hole 107 is connected between the circular straight cylinder 201 and the throat section thin-walled tube 204.

[0072] Preferably, during the dynamic adjustment in step (5), a non-linear deformation (bulging or concave) of each part of the thin-walled tube of the contraction section 103, throat section 104, and diffusion section 105 of the experimental Venturi tube 200 under the action of vacuum inside the annular cavity 208 is corrected as follows by the aperture linear smoothing processing module 217; S1. Measurement: The aperture size data of several axial positions of the thin-walled tubes of the contraction section 103, throat section 104, and diffusion section 105 of the experimental Venturi tube 200 measured online by the optoelectronic distance measurement sensor 216, S2. Calculation: Calculate the non-linear deformation errors of the thin-walled tube of the contraction section (including the large taper thin-walled tube 206 and the small taper thin-walled tube 207), the non-linear deformation error of the thin-walled tube of the throat section 204, and the non-linear deformation error of the thin-walled tube of the diffusion section 205 (including the large taper thin-walled tube 206 and the small taper thin-walled tube 207) respectively; S3, correction: according to the nonlinear deformation error data of different parts on the composite-shaped thin-walled sleeve 202, the temperature control system 220 of the aperture linear smoothing processing module 217 is turned on, and different heating powers are applied to different positions of the breathable elastic thermal expansion foaming porous material 218 through the power-adjustable annular low-temperature heating sheet 219 pre-buried in different parts inside the breathable elastic thermal expansion foaming porous material 218, so that the breathable elastic thermal expansion foaming porous material 218 forms a gradient temperature difference, thereby obtaining different elastic deformation compensation amounts at different parts, and the elastic deformation compensation amount acts on the composite-shaped thin-walled sleeve 202, so that the nonlinear deformation of the thin-walled tubes of the contraction section 103, throat section 104, and diffusion section 105 of the experimental venturi tube 200 is corrected.

[0073] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An optimized design method for a two-way flow wide-range Venturi flowmeter, characterized in that, The steps are as follows: (1) Preliminary design: Design the basic structure of the Venturi tube. The basic structure of the Venturi tube includes an inlet section, a contraction section, a throat section, a diffuser section, and an outlet section. Among them, the contraction section is a double-taper contraction section, the diffuser section is a double-taper diffuser section, and the inlet section, the double-taper contraction section, the double-taper diffuser section, and the outlet section are symmetrically arranged at both ends of the throat section with respect to the throat section; (2) Simulation optimization: Establish a simulation model of a two-way flow wide-range Venturi flowmeter aiming at improving the measurement accuracy under a wide range. Simulate and optimize the inner hole geometric dimensions of the inlet section, the contraction section, the throat section, the diffuser section, and the outlet section of the Venturi tube to obtain the simulation-optimized dimension data of the Venturi tube; (3) Fabrication of the test Venturi tube: According to the simulation-optimized dimension data of the Venturi tube, design and fabricate a test Venturi tube. Take the inner hole geometric dimensions of the inlet section, the contraction section, the throat section, the diffuser section, and the outlet section of the Venturi tube obtained by simulation optimization as the initial data of the inner hole geometric dimensions of the test Venturi tube, and set a geometric dimension adjusting device on the test Venturi tube so that the test Venturi tube becomes a dimension-adjustable test Venturi tube whose inner hole geometric dimensions of the contraction section, the throat section, and the diffuser section are synchronously adjustable; A geometric dimension on-line measurement module for dynamically measuring the inner hole geometric dimensions of the contraction section, the throat section, and the diffuser section of the Venturi tube during the test is also provided on the dimension-adjustable test Venturi tube; (4) Test verification: Install the dimension-adjustable test Venturi tube on a Venturi tube test bench for performance testing and verification to obtain the actual flow measurement accuracy data under a wide range; (5) Dynamic adjustment: Through the geometric dimension adjusting device on the test Venturi tube, on-line synchronously adjust the geometric dimensions of the contraction section, the throat section, and the diffuser section of the test Venturi tube, and test and verify its actual flow measurement accuracy under a wide range after the dimension adjustment; Through continuous adjustment several times, obtain the optimal geometric dimensions of the contraction section, the throat section, and the diffuser section of the test Venturi tube with the optimal actual flow measurement accuracy under a wide range; The optimal geometric dimensions are measured by the geometric dimension on-line measurement module through an optoelectronic distance measuring sensor; (6) Final design: Take the optimal geometric dimensions of the test Venturi tube obtained in the dynamic adjustment in step (5) as the final design dimensions of the Venturi tube of the two-way flow wide-range Venturi flowmeter.

2. The optimization design method of a two-way flow wide-range Venturi flowmeter according to claim 1, characterized in that, The size-adjustable test venturi tube comprises a round straight cylinder and a composite-shaped thin-walled tube connected to the middle position of the inner hole wall of the round straight cylinder, wherein the composite-shaped thin-walled tube comprises a contraction section thin-walled tube for forming the inner hole of the contraction section, a throat section thin-walled tube for forming the inner hole of the throat section, and a diffusion section thin-walled tube for forming the inner hole of the diffusion section, which are arranged and connected in sequence from left to right; the contraction section thin-walled tube is formed by connecting a large-tapered thin-walled tube with a relatively large taper and a small-tapered thin-walled tube with a relatively small taper, which are arranged in sequence from left to right; the diffusion section thin-walled tube is formed by connecting a large-tapered thin-walled tube with a relatively large taper and a small-tapered thin-walled tube with a relatively small taper, which are arranged in sequence from left to right; A small-taper thin-walled tube with a relatively small taper and a large-taper thin-walled tube with a relatively large taper, which are arranged in sequence from left to right, are connected to form a closed annular cavity; the composite-shaped thin-walled tube and the inner hole of the circular straight cylinder form a closed annular cavity; the geometric dimension adjustment device of the size-adjustable test venturi tube includes a vacuum suction port arranged on the circular straight cylinder and connected to the annular cavity, and a vacuum system connected to the vacuum suction port through a vacuum suction pipeline; a vacuum degree adjustment device for adjusting the vacuum degree inside the annular cavity is arranged on the vacuum suction pipeline.

3. The optimization design method of a two-way flow wide-range Venturi flowmeter according to claim 2, characterized in that, The vacuum degree regulating device includes a first electric regulating valve connected in series to the vacuum suction pipeline for cutting off or connecting the vacuum suction pipeline, a vacuum pressure gauge connected transversely to the vacuum suction pipeline for measuring the vacuum degree inside the annular cavity, and a second electric regulating valve for air intake connected transversely to the vacuum suction pipeline for adjusting the vacuum degree inside the annular cavity.

4. The optimized design method of a two-way flow wide-range Venturi flowmeter according to claim 1, characterized in that, The geometric dimension online measurement module comprises a plurality of photoelectric distance measuring sensors which are arranged on the circular straight cylinder at intervals along the axial direction.

5. The optimization design method of a two-way flow wide-range Venturi flowmeter according to claim 4, characterized in that A plurality of photoelectric distance measuring sensors are arranged at intervals along the circumferential direction on the same circumference of the circular straight cylinder.

6. The optimized design method of a two-way flow wide-range Venturi flowmeter according to claim 2, characterized in that, Based on the inner hole geometric dimensions of the inlet section, contraction section, throat section, diffusion section and outlet section of the Venturi tube obtained by simulation optimization, when manufacturing the experimental Venturi tube, based on the inner hole geometric dimensions of the contraction section, throat section and diffusion section of the Venturi tube obtained by simulation optimization, the inner hole dimension D of the throat section is appropriately reduced by a predetermined value e; during the test, the test verification is started from the smallest throat inner hole geometric dimension (De), and the composite-shaped thin-walled tube is gradually stretched in the longitudinal direction by gradually increasing the vacuum degree inside the annular cavity, so that the inner hole geometric dimensions of the contraction section, throat section and diffusion section of the experimental Venturi tube are gradually expanded until the largest throat section inner hole geometric dimension (D+e).

7. The optimized design method of a two-way flow wide-range Venturi flowmeter according to claim 2, characterized in that A linear aperture smoothing processing module is also provided for compensating for the nonlinear deformation of the composite-shaped thin-walled tube of the experimental venturi tube under the vacuum inside the annular cavity; the linear aperture smoothing processing module includes a breathable elastic thermal expansion foaming porous material filled inside the annular cavity, and a number of power-adjustable annular low-temperature heating sheets arranged at intervals along the axial direction are pre-buried inside the breathable elastic thermal expansion foaming porous material, and the power-adjustable annular low-temperature heating sheets are connected to the temperature control system.

8. The optimization design method of a two-way flow wide-range Venturi flowmeter according to claim 7, characterized in that, The breathable elastic thermal expansion foamed porous material adopts a silicone rubber breathable elastic thermal expansion foamed porous material containing 10-30% aluminum powder; the silicone rubber breathable elastic thermal expansion foamed porous material is formed by mixing aluminum powder, foaming agent, vulcanizing agent and silicone rubber matrix, filling the mixture into the annular cavity of the venturi tube, and decomposing the foaming agent under a certain temperature and pressure to trigger a vulcanization reaction.

9. The optimized design method of a two-way flow wide-range Venturi flowmeter according to claim 7, characterized in that, The air-permeable elastic thermal expansion foam porous material is provided with a detection avoidance hole for the detection light of the photoelectric distance measuring sensor to pass through; a metal corrugated telescopic tube for forming a pressure measuring hole in the throat section is connected between the circular straight cylinder and the throat section thin-walled tube.

10. The optimized design method of a two-way flow wide-range Venturi flowmeter according to claim 7, characterized in that, During the dynamic adjustment of step (5), the following correction processing is performed on the nonlinear deformation of the thin-walled tubes of the contraction section, throat section, and diffusion section of the experimental venturi tube under the vacuum inside the annular cavity through the aperture linear smoothing processing module; S1. Measurement: The aperture size data of the contraction section, throat section, and diffusion section of the venturi tube used in the test are measured online by a photoelectric distance measuring sensor at several locations in the axial direction. S2. Calculation: Calculate the nonlinear deformation error of the thin-walled tube in the contraction section, the nonlinear deformation error of the thin-walled tube in the throat section, and the nonlinear deformation error of the thin-walled tube in the diffusion section respectively; S3. Correction: According to the nonlinear deformation error data of different parts on the composite-shaped thin-walled sleeve, the temperature control system of the aperture linear smoothing processing module is turned on, and different heating powers are applied to different positions of the breathable elastic thermal expansion foamed porous material through the power-adjustable annular low-temperature heating sheets pre-buried in different parts inside the breathable elastic thermal expansion foamed porous material, so that the breathable elastic thermal expansion foamed porous material forms a gradient temperature difference, thereby obtaining different elastic deformation compensation amounts at different parts. The elastic deformation compensation amount acts on the composite-shaped thin-walled sleeve, so that the nonlinear deformation of the thin-walled tubes of the contraction section, throat section and diffusion section of the experimental Venturi tube is corrected.

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