An ultrasonic gas flow measurement device

Abstract

The invention discloses an ultrasonic gas flow measurement device. The device comprises a shell, an air inlet and an air outlet are arranged on the shell, an ultrasonic flow measurement pipeline is arranged in the shell, and the device is characterized in that: an airflow diffuse reflection device is also arranged in the shell, the airflow diffuse reflection device comprises an airflow three-dimensional diffuse reflection structure and an airflow guide structure, the airflow three-dimensional diffuse reflection structure is formed by a plurality of three-dimensional diffuse reflection curved surface unit arrays, the surface of the three-dimensional diffuse reflection curved surface unit is formed as an airflow three-dimensional diffuse reflection curved surface, the airflow guide structure is connected to the air inlet on the shell, the airflow guide structure has an air outlet, a certain distance and a certain angle are formed between the two-dimensional aperture surface of the air outlet of the airflow guide structure and the airflow three-dimensional diffuse reflection curved surface of the airflow three-dimensional diffuse reflection structure, so that the airflow flowing out of the air outlet of the airflow guide structure can be sprayed to the airflow three-dimensional diffuse reflection curved surface of the airflow three-dimensional diffuse reflection structure.

Description

Technical Field

[0001] The invention relates to an ultrasonic gas flow measurement device, belonging to the technical field of ultrasonic measurement. Background Art

[0002] Ultrasonic gas meter or ultrasonic flowmeter is a widely used ultrasonic gas flow measurement device. Due to the limitation of the size of the structure of ultrasonic gas meter or ultrasonic flowmeter, after the gas enters the chamber of the meter, it will produce incident impact, reflection of the cavity wall and components. After the incident and reflection mixing process, it will cause eddy current, turbulence, laminar flow and other phenomena in the chamber and flow measurement components, and the air flow uniformity is poor, which increases the difficulty of the flow algorithm of the metering software and affects the stability and accuracy of the metering, especially in the case of large flow. The impact on the stability and accuracy of the metering is more prominent. In addition, the density distribution law of the air flow in the flow measurement pipeline of the existing ultrasonic gas meter or ultrasonic flowmeter is: the middle layer is the densest, and as the distance from the middle layer increases, the air flow density will continue to decrease, and the air flow density is the lowest near the pipe wall, that is, a laminar distribution is formed. Due to the limitations of the structure, the laminar symmetry is usually not good, which also increases the difficulty of the flow algorithm of the metering software and affects the metering accuracy. Summary of the invention

[0003] In view of the above-mentioned defects existing in the prior art, the present invention provides an ultrasonic gas flow measurement device which can improve the uniformity of air flow distribution in a chamber and a flow measurement pipeline, and can improve the measurement stability and measurement accuracy.

[0004] The present invention is realized through the following technical scheme: an ultrasonic gas flow measurement device, comprising a shell, an air inlet and an air outlet are arranged on the shell, an ultrasonic flow measurement pipeline is arranged in the shell, and the characteristic is that: an airflow diffuse reflection device is also arranged in the shell, the airflow diffuse reflection device comprises an airflow three-dimensional diffuse reflection structure and an airflow guiding structure, the airflow three-dimensional diffuse reflection structure is formed by a plurality of three-dimensional diffuse reflection surface unit arrays, the surface of the three-dimensional diffuse reflection surface unit is formed as an airflow three-dimensional diffuse reflection surface, the airflow guiding structure is connected to the air inlet on the shell, the airflow guiding structure has an air outlet, the two-dimensional aperture surface of the air outlet of the airflow guiding structure is at a certain distance from the airflow three-dimensional diffuse reflection surface of the airflow three-dimensional diffuse reflection structure and a certain angle is formed so that the airflow flowing out of the air outlet of the airflow guiding structure can be sprayed to the airflow three-dimensional diffuse reflection surface of the airflow three-dimensional diffuse reflection structure.

[0005] In the present invention, an airflow diffuse reflection device is provided, and the gas flowing in from the air inlet and flowing out through the airflow guide structure is sprayed onto the airflow three-dimensional diffuse reflection surface of the airflow three-dimensional diffuse reflection structure. Through the reflection effect of the airflow diffuse reflection surface, the uniformity of the airflow distribution entering the shell and the flow measurement pipeline is improved, and the airflow distribution tends to be uniform.

[0006] The two-dimensional aperture surface of the air outlet of the airflow guiding structure in the present invention can be regarded as the air source wavefront, and the air source wavefront can be regarded as a two-dimensional air element array composed of many air source units, and the air source unit is simply referred to as an air element. The three-dimensional diffuse reflection surface of the airflow three-dimensional diffuse reflection structure can be regarded as a diffuse reflection array composed of many three-dimensional diffuse reflection surface units. Figure 1 As shown, the gas element constituting the two-dimensional gas element array is taken as ds. Each three-dimensional diffuse reflection surface unit can be regarded as a plurality of normal It is composed of different two-dimensional plane reflection elements da.

[0007] According to the principles of geometric optics, Snell reflection theorem and Huygens principle, when the airflow emitted by a single air element ds hits the two-dimensional plane reflection element da, θi = θr. Since the normal of the two-dimensional plane reflection element da is Different, that is, θi is different, the resulting reflection direction is different, such as the attached Figure 2 shown.

[0008] in, is the unit normal vector of the plane reflection element, θi is the incident angle of the airflow beam emitted by the air element, and θr is the reflection angle of the airflow beam passing through the plane reflection element. Figure 2 It can be seen that under the same gas element, due to the normal of the plane reflection element If the reflection is different, the direction of the airflow after reflection will be different.

[0009] Since the normal direction of the two-dimensional plane reflection element da that constitutes the three-dimensional diffuse reflection surface unit The reflection direction is not parallel, which results in multi-directional reflection. Figure 3 shown.

[0010] It can be seen that the superposition of the air flow beams of all the air elements on the air element array after being reflected by the three-dimensional diffuse reflection surface units on the three-dimensional diffuse reflection surface array makes the air flow distribution in the cavity and flow measurement components of the entire ultrasonic gas meter or ultrasonic flow meter tend to be uniform.

[0011] Furthermore, in order to improve the uniformity of airflow distribution, the shape of the three-dimensional diffuse reflection surface unit is a gyroscopic body or a translation body of a local curve of a trigonometric function; or a gyroscopic body or a translation body of a local curve of a hyperbolic function; or a gyroscopic body or a translation body of a local curve of a logarithmic function; or a gyroscopic body or a translation body of a local curve of an exponential function; or a gyroscopic body or a translation body of a local curve of a parabola.

[0012] Furthermore, in order to further improve the uniformity of airflow distribution, the airflow three-dimensional diffuse reflection structure is arranged on the inner upper surface of the shell.

[0013] Furthermore, the shape of the two-dimensional aperture surface of the air outlet of the airflow guiding structure is a circular plane aperture or a circular curved surface aperture or an elliptical plane aperture or an elliptical curved surface aperture or a rectangular plane aperture or a rectangular curved surface aperture.

[0014] Furthermore, in order to prevent the airflow from rotating in the airflow guiding structure, it is preferred that the shape of the two-dimensional aperture surface of the air outlet of the airflow guiding structure is a rectangular plane aperture or a rectangular curved surface aperture.

[0015] Furthermore, a laminar flow balancing structure is also provided in the shell, and the laminar flow balancing structure is provided at the opposite position of the inlet of the ultrasonic flow measurement pipeline, and the side of the laminar flow balancing structure opposite to the inlet of the ultrasonic flow measurement pipeline is a convex surface structure. The density distribution law of the airflow in the flow measurement pipeline of an ordinary ultrasonic gas meter or an ultrasonic flow meter is: the middle layer is the densest, and as the distance from the middle layer increases, the airflow density will continue to decrease, and the airflow density near the pipe wall is the lowest, that is, a laminar flow distribution is formed. Due to the limitations of the structure, the laminar flow symmetry is usually not good. From the relevant principles of acoustics, electromagnetic waves and optics and Snell's reflection theorem, it is known that the concave surface has a reflection bunching effect, and the convex surface has a reflection beam spreading effect. The present invention sets a laminar flow balancing structure at the opposite position of the inlet of the ultrasonic flow measurement pipeline, and uses the convex surface structure of the laminar flow balancing structure to change the reflection direction of the airflow, which can effectively change the laminar flow distribution of the airflow in the flow measurement pipeline, so that it has good uniformity and laminar symmetry, can reduce the calculation difficulty of the metering software, and effectively improve the metering accuracy.

[0016] Furthermore, in order to further effectively improve the laminar gradient and laminar symmetry of the airflow in the flow measurement pipeline, the convex surface structure is an ellipsoid, a spherical surface, a parabola, or a hyperbolic surface.

[0017] Furthermore, in order to improve the effect of improving the airflow in the flow measurement pipeline, the positive projection of the convex surface structure of the laminar flow balancing structure in the inlet direction of the ultrasonic flow measurement pipeline is greater than or equal to the inlet diameter of the ultrasonic flow measurement pipeline.

[0018] Furthermore, in order to enhance the effect of improving the airflow, the laminar flow balancing structure is arranged on the inner side wall of the shell.

[0019] The beneficial effects of the present invention are as follows: the present invention sets an airflow diffuse reflection device so that the gas flowing out of the air outlet of the guide structure is sprayed onto the airflow three-dimensional diffuse reflection surface of the airflow three-dimensional diffuse reflection structure. The airflow distribution entering the shell and the flow measurement pipeline tends to be uniform through the reflection effect of the airflow diffuse reflection surface, which can effectively reduce the eddy current, turbulence and laminar flow in the shell and the flow measurement pipeline, greatly reduce the difficulty of the flow algorithm within the flow range, and improve the stability and accuracy of measurement. The present invention sets a laminar flow balancing structure at the opposite position of the inlet of the flow measurement pipeline, and uses the convex surface structure of the laminar flow balancing structure to change the reflection direction of the airflow, which effectively improves the laminar distribution of the airflow in the flow measurement pipeline, making it have good uniformity and laminar symmetry, greatly reducing the calculation difficulty of the metering software, and effectively improving the metering accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a three-dimensional diffuse reflection surface array and a two-dimensional gas element array;

[0021] Figure 2 It is a schematic diagram of the reflection of the air flow beam of the air element through the two-dimensional plane reflection element;

[0022] Figure 3 It is a reflection schematic diagram of the air flow beam of the air element passing through the three-dimensional diffuse reflection surface unit formed by the two-dimensional plane reflection element;

[0023] Figure 4 It is a structural schematic diagram of a specific implementation mode of the present invention;

[0024] Figure 5 is a side view of an airflow guide elbow in a specific embodiment of the present invention;

[0025] Figure 6 It is a front view of the three-dimensional diffuse reflection structure of airflow in a specific embodiment of the present invention;

[0026] Figure 7 It is another form of the front view of the three-dimensional diffuse reflection surface in the present invention;

[0027] Figure 8 yes Figure 7 A top view of

[0028] In the figure, 1. air inlet, 2. air flow guide elbow, 21. air outlet of air flow guide elbow, 3. three-dimensional diffuse reflection structure of air flow, 31. three-dimensional diffuse reflection surface unit, 4. laminar flow balance structure, 5. inlet of ultrasonic flow measurement pipeline, 6. ultrasonic flow measurement pipeline, 7. ultrasonic upstream transducer, 8. ultrasonic downstream transducer, 9. pressure sensor, 10. temperature sensor, 11. PCB, 12. gas outlet elbow of flow measurement pipeline, 13. valve body, 14. shell, 15. air outlet. DETAILED DESCRIPTION

[0029] The present invention will be further described below by way of non-limiting embodiments and in conjunction with the accompanying drawings:

[0030] As attached Figure 4 The figure shows a schematic diagram of the internal structure of an ultrasonic gas meter or an ultrasonic flowmeter, which mainly includes a shell 14, on which an air inlet 1 and an air outlet 15 are arranged, and an ultrasonic flow measurement pipeline 6 is arranged in the shell 14. The front end of the ultrasonic flow measurement pipeline 6 is the inlet 5 of the ultrasonic flow measurement pipeline, and the ultrasonic flow measurement pipeline 6 is provided with an ultrasonic upstream transducer 7, an ultrasonic downstream transducer 8, a pressure sensor 9, a temperature sensor 10, and a PCB 11. The rear end of the ultrasonic flow measurement pipeline 6 is connected to a gas outlet elbow 12 and a valve body 13, and the valve body 13 is connected to the air outlet 15 on the shell 14. The above-mentioned settings in this embodiment are all prior art. Different from the prior art, in this embodiment, an airflow diffuse reflection device is also arranged in the shell 14, and the airflow diffuse reflection device includes an airflow three-dimensional diffuse reflection structure 3 and an airflow guide elbow 2. The airflow three-dimensional diffuse reflection structure 3 is formed by an array of a plurality of three-dimensional diffuse reflection surface units 31, and the surface of the three-dimensional diffuse reflection surface unit 31 is formed as an airflow three-dimensional diffuse reflection surface, as shown in the attached figure. Figure 6 The shape of the three-dimensional diffuse reflection surface unit 31 can be a gyroid or translation body of a local curve of a trigonometric function, a gyroid or translation body of a local curve of a hyperbolic function, a gyroid or translation body of a local curve of a logarithmic function, a gyroid or translation body of a local curve of an exponential function, or a gyroid or translation body of a local curve of a parabola, as shown in the attached figure. Figure 7 and attached Figure 8 The three-dimensional diffuse reflection surface is another form. The size of the three-dimensional diffuse reflection surface unit is determined by the size of the chamber in the shell of the actual gas meter or flow meter, the internal structure and the actual diffuse reflection performance. The material property of the three-dimensional diffuse reflection structure of the airflow can be metal or non-metal. Figure 4-Figure 5As shown, the airflow guiding elbow 2 is connected to the air inlet 1 on the shell 14, and the airflow guiding elbow 2 has an air outlet 21. There is a certain distance and a certain angle between the two-dimensional aperture surface of the air outlet 21 of the airflow guiding elbow 2 and the airflow three-dimensional diffuse reflection curved surface of the airflow three-dimensional diffuse reflection structure 3, so that the airflow flowing out of the air outlet 21 of the airflow guiding elbow 2 can be sprayed onto the airflow three-dimensional diffuse reflection curved surface of the airflow three-dimensional diffuse reflection structure. The shape of the two-dimensional aperture surface of the air outlet 21 of the airflow guiding elbow 2 can be a circular plane aperture or a circular curved surface aperture or an elliptical plane aperture or an elliptical curved surface aperture or a rectangular plane aperture or a rectangular curved surface aperture. Since the airflow is easy to rotate in a circular or elliptical pipe, it is preferred that the shape of the two-dimensional aperture surface of the air outlet 21 of the airflow guiding elbow 2 is a rectangular plane aperture or a rectangular curved surface aperture. The distance between the two-dimensional aperture surface of the air outlet 21 of the airflow guiding elbow 2 and the airflow three-dimensional diffuse reflection surface of the airflow three-dimensional diffuse reflection structure 3 and the angle formed therebetween are actually determined according to the chamber size and internal structure of the actual gas meter or flow meter, so that the two-dimensional aperture surface of the air outlet 21 and the airflow three-dimensional diffuse reflection surface can form an airflow diffuse reflection with good performance. In this embodiment, preferably, the airflow three-dimensional diffuse reflection structure 3 is arranged on the inner upper surface of the shell 14, the two-dimensional aperture surface of the air outlet 21 of the airflow guiding elbow 2 is selected as a rectangular plane aperture, and the two-dimensional aperture surface of the air outlet 21 is obliquely located at the side and lower side of the airflow three-dimensional diffuse reflection structure 3, so that the airflow flowing out of the air outlet 21 of the airflow guiding elbow 2 can be sprayed onto the airflow three-dimensional diffuse reflection surface of the airflow three-dimensional diffuse reflection structure 3 at a certain angle, and the airflow is reflected in multiple directions by the reflection effect of the airflow diffuse reflection surface, so that the airflow distribution in the chamber and flow measurement component of the entire ultrasonic gas meter or ultrasonic flowmeter tends to be uniform.

[0031] In order to improve the airflow distribution state in the ultrasonic flow measurement pipeline 6, in this embodiment, a laminar flow equalization structure 4 is also provided in the housing 14. The laminar flow equalization structure 4 is provided at the opposite position of the inlet 5 of the ultrasonic flow measurement pipeline 6, and the side of the laminar flow equalization structure 4 opposite to the inlet 5 of the ultrasonic flow measurement pipeline is a convex surface structure. The convex surface structure can be an ellipsoid, a sphere, a parabola, or a hyperboloid. The laminar flow equalization structure 4 can be a solid structure or a hollow structure. The material properties of the laminar flow equalization structure 4 can be metal or non-metal. In order to ensure the improvement effect on the airflow in the flow measurement pipeline, the positive projection of the convex surface structure of the laminar flow equalization structure 4 in the inlet direction of the ultrasonic flow measurement pipeline should be greater than or equal to the caliber of the inlet 5 of the ultrasonic flow measurement pipeline 6. The size of the laminar flow equalization structure and the distance from the inlet 5 of the ultrasonic flow measurement pipeline 6 are determined according to the size of the chamber in the housing of the ultrasonic gas meter or the ultrasonic flow meter. In this embodiment, the laminar flow balancing structure 4 is arranged on the inner wall of the housing 14 opposite to the inlet 5 of the ultrasonic flow measurement pipeline 6, which can save space in the housing and reduce interference with the airflow.

[0032] The airflow direction in the present invention is: the air source flows from the air inlet 1 through the airflow guide elbow 2, and the airflow is sprayed toward the airflow three-dimensional diffuse reflection structure 3 on the two-dimensional aperture surface of the airflow guide elbow 2. After being reflected by the three-dimensional diffuse reflection surface of the airflow, the uniformity of the airflow distribution in the shell is improved. Part of the airflow is then reflected by the laminar flow balance structure 4 and mixed with the straight airflow to enter the inlet 5 of the ultrasonic flow measurement pipeline 6, and then flows through the ultrasonic flow measurement pipeline 6, so that the airflow distribution in the ultrasonic flow measurement pipeline 6 is more uniform and has good symmetry. The airflow flows through the gas outlet elbow 12, valve body 13, and air outlet 15 of the flow measurement pipeline and enters the user's stove.

[0033] This embodiment tests the airflow distribution and laminar flow distribution in the chamber and measuring pipeline of three types of ultrasonic gas meters or ultrasonic flow meters: an existing ordinary ultrasonic gas meter or ultrasonic flow meter, an ultrasonic gas meter or ultrasonic flow meter with an additional airflow diffuse reflection device, and an ultrasonic gas meter or ultrasonic flow meter with an additional airflow diffuse reflection device and a laminar flow balancing structure. The test results are compared and the test results are shown in Table 1.

[0034] From Table 1, we can see that:

[0035] In the test of air flow distribution and laminar flow distribution in the chamber and measuring pipeline of ordinary ultrasonic gas meter or ultrasonic flow meter, it can be seen that the air flow distribution uniformity in the chamber of ordinary ultrasonic gas meter or ultrasonic flow meter is not good, the air flow in the flow measurement pipeline is uneven, the laminar flow is obvious, and the symmetry is not good. The highest sound speed is at the coordinate -2.64mm, the maximum sound speed is 13.846m / s, and the minimum is 10.346m / s.

[0036] In the test of the airflow distribution and laminar distribution in the chamber and measuring pipeline of an ultrasonic gas meter or ultrasonic flow meter with an added airflow diffuse reflection device, it can be seen that the addition of the airflow diffuse reflection device makes the airflow distribution in the chamber and the flow measurement pipeline relatively uniform, and the laminar distribution in the flow measurement pipeline is improved, but the improvement effect is not very ideal. This shows that the diffuse reflection device only improves the airflow uniformity in the chamber and the flow measurement pipeline, and has little effect on the laminar distribution in the flow measurement pipeline. The laminar gradient is large and the laminar flow is asymmetric. The highest sound velocity is still at the coordinate -2.65mm, with a maximum of 14.022m / s and a minimum of 10.371m / s.

[0037] In the test of the airflow distribution and laminar distribution in the chamber and measuring pipeline of the ultrasonic gas meter or ultrasonic flow meter with the added airflow diffuse reflection device and laminar flow balance structure, it can be known that the airflow after passing through the airflow diffuse reflection device is reflected and mixed by the laminar flow balance structure, so that the airflow entering the measuring pipeline tends to be uniform, the laminar flow gradient is significantly reduced, the highest sound velocity is at the coordinate 0mm position, and the laminar flow has good symmetry, with a maximum of 13.923m / s and a minimum of 11.326m / s. It can be seen that the laminar flow balance structure greatly improves the laminar flow uniformity and symmetry of the airflow in the flow measurement pipeline.

[0038] It can be seen from the above test results that the present invention not only greatly improves the uniformity of airflow distribution in the chamber and the measuring pipeline, but also makes the laminar symmetry in the measuring pipeline reach a quasi-ideal level, creating conditions for effectively reducing the difficulty of the ultrasonic flow algorithm while improving the accuracy and stability of measurement.

[0039] Table 1 Results of air flow and laminar flow distribution in ultrasonic gas meter or ultrasonic flow meter chamber and flow measurement pipeline

[0040]

[0041]

[0042] The other parts of this embodiment are all prior art and will not be described in detail here.

Claims

1. An ultrasonic gas flow measurement device, comprising a housing, the housing being provided with an air inlet and an air outlet, and the housing being provided with an ultrasonic flow measurement pipeline, wherein: An airflow diffuse reflection device is also arranged in the shell, and the airflow diffuse reflection device includes an airflow three-dimensional diffuse reflection structure and an airflow guiding structure. The airflow three-dimensional diffuse reflection structure is formed by an array of several three-dimensional diffuse reflection curved surface units, and the surface of the three-dimensional diffuse reflection curved surface unit is formed as an airflow three-dimensional diffuse reflection curved surface. The airflow guiding structure is connected to the air inlet on the shell, and the airflow guiding structure has an air outlet. The two-dimensional aperture surface of the air outlet of the airflow guiding structure is at a certain distance from the airflow three-dimensional diffuse reflection curved surface of the airflow three-dimensional diffuse reflection structure, and a certain angle is formed so that the airflow flowing out of the air outlet of the airflow guiding structure can be sprayed onto the airflow three-dimensional diffuse reflection curved surface of the airflow three-dimensional diffuse reflection structure.

2. The ultrasonic gas flow measurement device according to claim 1, characterized in that: The shape of the three-dimensional diffuse reflection surface unit is a gyroscopic or translational body of a local curve of a trigonometric function; or a gyroscopic or translational body of a local curve of a hyperbolic function; or a gyroscopic or translational body of a local curve of a logarithmic function; or a gyroscopic or translational body of a local curve of an exponential function; or a gyroscopic or translational body of a local curve of a parabola.

3. The ultrasonic gas flow measurement device according to claim 1, characterized in that: The airflow three-dimensional diffuse reflection structure is arranged on the inner upper surface of the shell.

4. The ultrasonic gas flow measurement device according to claim 1, characterized in that: The shape of the two-dimensional aperture surface of the air outlet of the airflow guiding structure is a circular plane aperture or a circular curved surface aperture or an elliptical plane aperture or an elliptical curved surface aperture or a rectangular plane aperture or a rectangular curved surface aperture.

5. The ultrasonic gas flow measurement device according to claim 4, characterized in that: The shape of the two-dimensional aperture surface of the air outlet of the airflow guiding structure is a rectangular plane aperture or a rectangular curved surface aperture.

6. The ultrasonic gas flow measurement device according to claim 1, 2, 3, 4 or 5, characterized in that: A laminar flow balancing structure is also provided in the shell, and the laminar flow balancing structure is arranged at a position opposite to the inlet of the ultrasonic flow measurement pipeline. The side of the laminar flow balancing structure opposite to the inlet of the ultrasonic flow measurement pipeline is a convex surface structure.

7. The ultrasonic gas flow measurement device according to claim 6, characterized in that: The convex surface structure is an ellipsoid, a sphere, a parabola or a hyperboloid.

8. The ultrasonic gas flow measurement device according to claim 6, characterized in that: The orthographic projection of the convex surface structure of the laminar flow balancing structure in the inlet direction of the ultrasonic flow measurement pipeline is greater than or equal to the inlet diameter of the ultrasonic flow measurement pipeline.

9. The ultrasonic gas flow measurement device according to claim 7, characterized in that: The laminar flow balancing structure is arranged on the inner side wall of the shell.

Images