An ultrasonic water meter structure for realizing a UOD0 installation environment

Abstract

The present application relates to water meter equipment technical field, especially relates to a kind of ultrasonic water meter structure for realizing U0D0 installation environment, and the ultrasonic water meter is DN20 ultrasonic water meter, and the one end of DN20 ultrasonic water meter is connected with DN20 ball valve, the inside of DN20 ultrasonic water meter is equipped with the whole of movement, and the cross section of the internal flow passage of movement is multi-arc line structure.The beneficial effects of the present application are:the flow passage structure of the multi-arc combination designed in the present application can realize the U0D0 installation of ultrasonic water meter, and numerical simulation analysis can prove that the influence caused by ball valve disturbance when the ball valve opening of the present application is 30 ° is below 1%, and the pressure of U0D0 water meter can be reached, and the influence of the ball valve of 30 ° opening of the present application on measurement accuracy is 2.96%, by comparing with conventional circular flow passage structure, it is confirmed that the anti-disturbance effect of the multi-arc structure of the present application is obviously improved, and has good rectification effect.

Description

Technical Field

[0001] This invention relates to the field of water meter equipment technology, and in particular to an ultrasonic water meter structure that enables UOD0 installation environment. Background Technology

[0002] Ultrasonic water meters measure the average linear velocity of water flow along the propagation path of ultrasonic waves, and use this linear velocity to calculate the average surface velocity of the meter's cross-section. To ensure measurement accuracy, it is necessary to accurately measure the time difference between upstream and downstream propagation of the ultrasonic signal, and to maintain a stable velocity distribution across the meter's cross-section. In practical use, the front end of the water meter is often connected to flow-disrupting components such as bends and valves, causing distortion of the velocity distribution across the meter's cross-section and affecting measurement accuracy. To ensure metering accuracy, ordinary ultrasonic water meters require straight pipe sections (U10D5) with 10 times and 5 times the inner diameter before and after the meter, respectively, to eliminate the influence of flow disturbance. However, due to limited installation space, the installation conditions of U10D5 cannot be met in many cases. To solve this problem, many manufacturers have achieved installation environments where no straight pipe sections (U0D0) are needed before or after the meter by adding rectifiers and changing the flow channel structure.

[0003] Modifying the flow channel structure and using changes in the flow channel structure to weaken the influence of turbulence in front of the water meter is an important method in the development of U0D0 water meters. For example, using a necking method can reduce the influence of turbulence to a certain extent, but its effect on strong turbulence is limited. Some companies have achieved the installation conditions for U0D0 by using elliptical or rectangular flow channel designs to weaken the influence of turbulence in front of the water meter.

[0004] Among the many factors affecting the stability of the flow field, the valve in front of the water meter has a significant impact on the measurement accuracy of the water meter. Some companies install ball valves in front of the water meter, and consider that the U0D0 installation conditions have been met when the ball valve opening is 10-15° and the measurement requirements are met.

[0005] This application presents a flow channel structure and ball valve opening scheme that differs from those of other manufacturers, which can effectively reduce the impact of turbulence caused by the ball valve in front of the water meter and achieve U0D0 installation. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this invention provides an ultrasonic water meter structure that enables UOD0 installation environment.

[0007] An ultrasonic water meter structure for UOD0 installation environment, comprising an ultrasonic water meter, characterized in that:

[0008] The ultrasonic water meter is a DN20 ultrasonic water meter. A DN20 ball valve is connected in series at one end of the DN20 ultrasonic water meter. The DN20 ultrasonic water meter has an internal mechanism. The cross-section of the internal flow channel of the mechanism is a multi-segment arc structure.

[0009] Furthermore, in order to better realize the present invention, the diameter of the central part of the movement at the center of the entire movement is 19cm.

[0010] Furthermore, in order to better realize the present invention, the multi-segment arc structure is in the shape of a symmetrical gourd, including upper and lower middle arcs that are concave inward on the upper and lower sides, left and right middle arcs that protrude outward on the left and right sides, and connecting arcs connecting the two.

[0011] Furthermore, to better realize the present invention, the diameter of the upper and lower middle arcs is 8cm; the diameter of the left and right middle arcs is 8.5cm; the diameter of the connecting arc is 3cm; and the angle between the center line of the upper and lower middle arcs and the tangent of the connecting arc is 75°.

[0012] Furthermore, to better realize the present invention, the opening degree of the DN20 ball valve is 30°.

[0013] The beneficial effects of this invention are:

[0014] The multi-segment circular arc combined flow channel structure designed in this invention can realize the U0D0 installation of ultrasonic water meters. Numerical simulation analysis can prove that when the ball valve opening degree is 30°, the impact of ball valve turbulence is less than 1%, which can achieve the pressure of U0D0 water meters. The ball valve with a 30° opening degree of this invention has an impact of 2.96% on the measurement accuracy. By comparing with the conventional circular flow channel structure, it is confirmed that the anti-turbulence effect of the multi-segment circular arc structure of this invention is significantly improved, and it has a good rectification effect. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an ultrasonic water meter.

[0016] Figure 2 This is a three-dimensional structural diagram of the DN20 diameter ultrasonic water meter series ball valve of the present invention.

[0017] Figure 3 This is a three-dimensional structural diagram of the movement of the present invention;

[0018] Figure 4 This is a front view of the movement of the present invention;

[0019] Figure 5 For the present invention Figure 4 A sectional view at point 4-4;

[0020] Figure 6 This is a grid diagram of the water meter of the present invention when no ball valve is installed in front of it;

[0021] Figure 7 A grid diagram for installing a 30° opening ball valve in front of the water meter according to the present invention;

[0022] Figure 8 This is a velocity distribution diagram of the horizontal cross section when no ball valve is installed in front of the water meter according to the present invention;

[0023] Figure 9 This is a vertical cross-sectional velocity distribution diagram when no ball valve is installed before the water meter of the present invention;

[0024] Figure 10 The velocity distribution diagram of the horizontal cross section of the ball valve with a 30° opening installed in front of the water meter according to the present invention;

[0025] Figure 11 The vertical cross-sectional velocity distribution diagram of the ball valve with a 30° opening installed in front of the water meter according to the present invention;

[0026] Figure 12 This is a table showing the quantitative results of the effect of the ball valve of the present invention on measurement performance;

[0027] Figure 13 A grid diagram for installing ball valves before a standard water meter;

[0028] Figure 14 A grid diagram showing a standard water meter without a ball valve installed before it.

[0029] Figure 15 This is a velocity distribution diagram of a horizontal section before a ball valve is installed in front of a standard water meter.

[0030] Figure 16 A velocity distribution diagram of a horizontal cross-section for a ball valve installed before a standard water meter;

[0031] Figure 17 This provides quantitative results regarding the impact of ball valves on the measurement performance of ordinary water meters.

[0032] In the picture,

[0033] 1. DN20 ultrasonic water meter, 2. DN20 ball valve, 3. Mechanism as a whole, 101. Middle part of the mechanism, 102. Multi-segment arc structure, 103. Upper and lower middle arcs, 104. Left and right middle arcs, 105. Connecting arcs. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Figure 1 This is a schematic diagram of the existing ultrasonic water meter principle. As shown in the figure, most small-diameter ultrasonic water meters currently use a U-shaped reflective structure.

[0038] Two ultrasonic transducers, A and B, can both emit and receive ultrasonic signals. The ultrasonic wave emitted by transducer A is reflected by a reflector and then received by transducer B. The propagation time of the ultrasonic wave downstream is:

[0039]

[0040] The ultrasonic wave emitted by transducer B propagates backward and is received by transducer A. The time for the ultrasonic signal to propagate backward is:

[0041]

[0042] The time difference between upstream and downstream propagation is:

[0043]

[0044] In the above formulas, uL is the linear average velocity of the fluid along the sound propagation path, m / s; τ is the time delay, s; D is the pipe diameter, m; L is the distance of the ultrasonic wave propagation path, m; and c is the speed of sound, m / s.

[0045] Since the flow velocity is much smaller than the speed of sound, u is neglected. L 2 cos 2 θ, yielding the following formula:

[0046]

[0047]

[0048] In practical calculations, the K coefficient is often used to define the ratio of the linear average velocity uL to the surface average velocity uS:

[0049]

[0050] The expression for the instantaneous volumetric flow rate q is:

[0051]

[0052] In the formula, A is the cross-sectional area of ​​the measurement channel, m 2 .

[0053] As can be seen from the principle of ultrasonic water meters, the water meter measures the average linear velocity of the water flow along the propagation path of the ultrasonic wave, and uses the linear velocity to calculate the average surface velocity of the water meter's cross-section. To ensure measurement accuracy, it is necessary to accurately measure the time difference between the upstream and downstream propagation of the ultrasonic signal, and to keep the water flow velocity distribution across the water meter's cross-section stable.

[0054] Therefore, the applicant designed such as Figures 2-5 The structure shown in the figure is an ultrasonic water meter with a DN20 diameter. As shown, the movement is installed in the measuring section in the middle of the water meter. The shape of the middle part of the movement is designed as a multi-segment arc structure, and the opening degree of the connected ball valve is set to 30°.

[0055] The design calculation model is as follows:

[0056] In most cases, the flow within an ultrasonic water meter is turbulent; therefore, a turbulence model is used for numerical simulation. The turbulence model used is the k-ω turbulence model, with a wall correction function applied near the wall. The fluid model equations are as follows:

[0057]

[0058]

[0059] In the formula u j Represents the velocity in the coordinate system at x j The coordinate components of the direction are ρ, air density, P, and μ, respectively. In Equation 3-2... For Reynolds stress, turbulence models in engineering are widely based on the Boussinesp assumption, then

[0060]

[0061] The standard k-ω model is a two-equation turbulence model that solves two separate transport equations based on the turbulent kinetic energy k and ω:

[0062]

[0063]

[0064] In the formula G k G represents the turbulent kinetic energy generated due to the influence of the average velocity gradient. w Y represents the turbulent dissipation rate generated. k and Y w S represents the diffusivity of k and ω due to turbulence, respectively. k and S w Indicates a user-defined source item, Γ k and Γ w Let k and ω represent the effective diffusion equations, respectively, and their expressions are as follows:

[0065]

[0066]

[0067]

[0068] In the formula, σ k and σ ω ω represents the Prandtl number for turbulence, k, and ω, respectively.

[0069] Next, simulations were performed for two scenarios: one with interference from a ball valve in front of the ultrasonic water meter and the other without. The computational domain and mesh are shown below. Figure 6 Figure 7 A 10D straight pipe section was installed before and after the ultrasonic water meter. Figure 7 The ball valve is directly connected to the ultrasonic water meter, with no straight pipe section in between.

[0070] In the numerical simulation, four flow rates of 4 m³ / h, 2.5 m³ / h, 1.25 m³ / h, and 0.75 m³ / h were selected. A velocity inlet boundary condition was set at the inlet, and the velocity was calculated based on the flow rate. A pressure outlet was set at the inlet, and atmospheric pressure was used as the outlet pressure.

[0071] Figures 8-11 The velocity distribution within the flow channel is presented in simulations with and without a ball valve. Figure 8 Figure 9 As shown, without the ball valve causing flow disturbance, the velocity is symmetrically distributed after passing through the straight pipe section, and the velocity is also symmetrically distributed in the measurement section behind the reflector. Figure 10 Figure 11 The flow pattern is shown by a ball valve with a 30° opening connected in series before the water meter. It can be seen that the velocity distribution after passing through the ball valve is highly uneven. Figure 10 In the middle section, the velocity above the ball valve decreases significantly while the velocity below increases significantly. However, upon entering the measurement section, the velocity distribution gradually becomes symmetrical, and in the measurement section after passing the reflector, the velocity distribution is basically symmetrical. (Comparison) Figure 9 and Figure 11 It can also be seen that the two have become largely the same.

[0072] Figures 8-11 The comparison shows that the multi-segment arc-shaped flow channel structure can effectively reduce the turbulence caused by the ball valve, and quantitative analysis can be performed using the results of numerical simulation. The ultrasonic signal propagates between two reflectors with a diameter of 10 mm. Five streamlines are drawn between the reflectors, with one streamline positioned at the center of the reflector and the other four at a distance of 2.5 mm from the center. The average velocity of these five streamlines represents the flow velocity of the water between the reflectors. A quantitative result can be obtained by comparing the streamline velocities with and without the ball valve. The calculation results are shown in [the table below]. Figure 12 .

[0073] Depend on Figure 12 It can be seen that the difference in the average value of the five streamlines at each flow point is less than 1% when there is a ball valve before the water meter and when there is no ball valve. According to the requirements for Class 2 accuracy of ultrasonic water meters, the measurement error must be less than ±2% when the flow rate exceeds the boundary flow point. Based on this standard, if the error is controlled within ±0.5% when there is no ball valve, the installation conditions for U0D0 can be met.

[0074] To clarify the anti-turbulence characteristics of the multi-segment circular arc structure in this embodiment, numerical simulations were also performed on common water meters with circular flow channel structures. The calculation model is shown below. Figure 13 Figure 14 The cross-section of the measuring channel in the middle of the reflector is circular.

[0075] Figure 15 Figure 16 The velocity distribution from the numerical simulation is presented. It can be seen that even after installing a ball valve in front of the water meter, the uneven water flow entering the measuring section still exhibits asymmetry behind the reflector. Figure 16 It can be seen that the asymmetry of the water flow is more obvious in front of (on the right side) of the measurement section. As the flow distance increases, the asymmetry is improved behind the measurement section, indicating that the effect of eliminating turbulence is poor.

[0076] Figure 17 The quantitative analysis is presented, using the same method as above. Five streamlines are taken between the two reflectors, and the influence of the ball valve on the measurement characteristics is analyzed by the average velocity of the five streamlines. Figure 17 The data listed shows that ordinary water meters with a circular measuring section have a poor effect on reducing the turbulence caused by ball valves. The impact of ball valves reaches 2.96%, which is close to 3%, and cannot meet the installation requirements of U0D0.

[0077] This embodiment achieves U0D0 installation of the ultrasonic water meter through structural optimization, designing a multi-segment circular arc flow channel structure. Numerical simulation analysis was used to analyze the effect of the multi-segment circular arc flow channel on reducing turbulence interference. The simulation results show that when the ball valve opening is 30°, the impact of ball valve turbulence is less than 1%, which can achieve the pressure of the U0D0 water meter. Numerical simulation analysis was also used to analyze the anti-turbulence characteristics of a conventional circular flow channel. The impact of a 30° ball valve opening on measurement accuracy is 2.96%. Comparison with the conventional circular flow channel structure confirms that the multi-segment circular arc structure significantly improves the anti-turbulence effect and has good rectification performance.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. An ultrasonic water meter structure for UOD0 installation environment, comprising an ultrasonic water meter, characterized in that: The ultrasonic water meter is a DN20 ultrasonic water meter (1). A DN20 ball valve (2) is connected in series at one end of the DN20 ultrasonic water meter (1). The DN20 ultrasonic water meter (1) has a core assembly (3) inside. The cross-section of the internal flow channel of the core assembly (3) is a multi-segment arc structure (102). The multi-segment arc structure (102) is symmetrically gourd-shaped, including upper and lower middle arcs (103) that are concave inward on the upper and lower sides, left and right middle arcs (104) that protrude outward on the left and right sides, and connecting arcs (105) that connect the two. The opening degree of the DN20 ball valve (2) is 30°. The diameter of the core middle part (101) at the center of the core assembly (3) is 19cm. The diameter of the upper and lower middle arcs (103) is 8cm. The diameter of the left and right middle arcs (104) is 8.5cm; The diameter of the connecting arc (105) is 3cm; The angle between the center line of the upper and lower middle arcs (103) and the tangent of the connecting arc (105) is 75°.

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