A flow field adaptive adjustment device for a dual-channel ultrasonic gas flowmeter

Abstract

The present invention relates to the technical field of flow field regulation, and specifically relates to a flow field adaptive regulation device for a dual-channel ultrasonic gas flowmeter, which includes a first circular pipe section, a second circular pipe section, and a square pipe section connecting the first circular pipe section and the second circular pipe section. The square pipe section is provided with a first downstream transducer and a second downstream transducer arranged side by side, and a first upstream transducer and a second upstream transducer arranged side by side. The design of the square pipe at the ultrasonic flowmeter simplifies the correction calculation of the flow velocity, and the flow equalizing device regulates the flow field within the pipe cross-section, ensuring the measurement accuracy of the ultrasonic flowmeter.

Description

Technical Field

[0001] The present invention relates to the technical field of flow field regulation, and specifically to a flow field adaptive regulation device for a dual-channel ultrasonic gas flowmeter. Background Art

[0002] The dual-channel ultrasonic flowmeter is based on the Time-of-Flight (TOF) principle. It calculates the flow velocity by measuring the time difference between the ultrasonic waves propagating in the fluid in the downstream and upstream directions. Its core structure is to symmetrically install two pairs of transducers (transmitters / receivers) on both sides of the pipeline, forming two independent acoustic wave paths. When the fluid flows, the propagation speed of the ultrasonic wave in the downstream direction will increase (speed of sound + flow velocity), while in the upstream direction it will decrease (speed of sound - flow velocity). The time difference between the two paths is proportional to the fluid flow velocity. By measuring the two sets of time differences and taking the average value, the error caused by the asymmetric flow field or installation deviation in the single channel can be significantly reduced, and the measurement accuracy can be improved (typical error ±0.5% - 1%). The dual-channel design can also exclude local eddy current or impurity interference through cross-verification, and is applicable to various media such as gases and liquids. Especially when the pipeline flow field is uneven, it is more reliable than the single channel.

[0003] Traditional ultrasonic flowmeters use a circular pipeline design. However, in the case of low flow velocity or laminar flow, the right-angle structure of the square pipeline can suppress the common secondary flow in the circular pipeline. Moreover, the square pipeline is convenient for arranging multiple pairs of ultrasonic transducers (such as 4 channels or 8 channels). By measuring through multiple paths, the flow field information can be captured more comprehensively, reducing the error caused by the asymmetric velocity distribution. In addition, the square pipeline design makes the flow field change in the pipeline more smooth, and the square cross-section simplifies the correction calculation method when calculating the flow velocity. However, when the fluid enters the square pipeline from the circular pipeline, disturbances will occur, and corresponding devices need to be set up to regulate the flow field. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a flow field adaptive regulation device for a dual-channel ultrasonic gas flowmeter. The square pipeline design at the ultrasonic flowmeter simplifies the correction calculation of the flow velocity, and the flow equalizing device regulates the flow field within the pipeline cross-section, ensuring the measurement accuracy of the ultrasonic flowmeter.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A flow field adaptive adjustment device for a dual-channel ultrasonic gas flowmeter, comprising a first circular pipe section, a second circular pipe section, and a square pipe section connecting the first circular pipe section and the second circular pipe section. A first downstream transducer and a second downstream transducer arranged side by side, and a first upstream transducer and a second upstream transducer arranged side by side are provided on the square pipe section. A flow straightening device and an inlet device are arranged in the first circular pipe section. The fluid enters the flow straightening device from the inlet device, and the fluid enters the square pipe section from the first circular pipe section through the flow straightening device to stabilize the flow field. A rectifying device is arranged at the upstream positions of the first upstream transducer and the second upstream transducer in the square pipe section. An actuating component is further arranged on one side of the first upstream transducer and the second upstream transducer on the square pipe section. The actuating component can cover the concave area on one side of the first upstream transducer and the second upstream transducer.

[0007] Further, the inlet device includes a support ring located upstream and an inlet pipe facing downstream. The flow straightening device includes an outlet pipe facing upstream and a drainage ring located downstream. The inner wall of the inlet pipe forms a conical surface, and the inner diameter of the inlet pipe is larger than the outer diameter of the outlet pipe.

[0008] Further, a second cavity is formed by enclosing the support ring, the inlet pipe, and the inner wall of the first circular pipe section. A first cavity is formed by enclosing the drainage ring, the outlet pipe, and the inner wall of the first circular pipe section. The first cavity and the second cavity are arranged facing each other. After being guided by the conical surface of the inlet pipe, part of the fluid can enter the first cavity, and after being reflected by the drainage ring, it can enter the second cavity and generate a circulating flow.

[0009] Further, a plurality of diversion holes are evenly arranged on the drainage ring of the flow straightening device. The diversion holes are composed of circular holes and hemispherical plates arranged on the circular holes. After the fluid passes through the circular holes of the diversion holes, it is acted on by the hemispherical plates and changes direction. And the drainage ring is divided into multiple intervals, and the diversion directions of the diversion holes in different intervals are different.

[0010] Further, the cross-sectional area of the outlet pipe of the flow straightening device is the first area. The cross-sectional area of the square pipe section is the second area. The area in the second area excluding the projection of the first area in the second area is the drainage area. The diversion holes in different intervals of the drainage ring evenly guide the fluid into the drainage areas at different positions in the second area.

[0011] Further, the direction extending from the center of the square pipe section to a right-angle vertex is the third direction. The vertical direction adjacent to the third direction is the first direction. The horizontal direction adjacent to the third direction is the second direction. The diversion holes in the interval between the first direction and the third direction on the drainage ring of the flow straightening device are arranged facing the third direction. The diversion holes in the interval between the second direction and the third direction on the drainage ring of the flow straightening device are arranged facing the third direction.

[0012] Furthermore, the opening of the hemispherical plate on the circular hole of the diversion hole in the interval between the first direction and the third direction faces the third direction; the opening of the hemispherical plate on the circular hole of the diversion hole in the interval between the second direction and the third direction faces the third direction; no hemispherical plate is provided on the circular hole of the diversion hole distributed along the third direction.

[0013] Furthermore, the first downstream transducer, the second downstream transducer, the first upstream transducer, and the second upstream transducer are inclined; after the ultrasonic waves are emitted from the first upstream transducer and the second upstream transducer, they are received by the first downstream transducer and the second downstream transducer along a straight path; the straight path of the ultrasonic waves is perpendicular to the transmitting / receiving end face of the transducer; a recessed area is formed between the transmitting / receiving end face of the transducer and the pipe wall of the square pipe section; a slider of the actuating assembly is provided in the recessed area.

[0014] Furthermore, the slider of the actuating assembly is connected to the sealing plate through an elastomer; an electromagnetic coil is installed outside the sealing plate, and the slider is driven to move and reset through the electromagnetic coil and the elastomer.

[0015] Furthermore, the slider slides along the channel in the square pipe section, and limiting grooves are provided on both sides of the channel; limiting parts are provided on both sides of the slider, and the limiting parts cooperate with the limiting grooves; a groove is also provided on the slider.

[0016] Compared with the prior art, the present invention provides a flow field adaptive adjustment device for a dual-channel ultrasonic gas flowmeter, which has the following beneficial effects: the square pipe design at the ultrasonic flowmeter of the present invention makes the change of the flow field in the pipe smoother, and the square cross-section simplifies the correction calculation method during the calculation of the flow velocity. The flow field in the square pipe can be adjusted through the flow equalizing device to ensure that the fluid in each area of the square cross-section passes through the rectifying device at a uniform speed. At the same time, the inlet device and the flow equalizing device can reduce the liquid water and solid impurities in the natural gas; an actuating device is provided at the ultrasonic transducer to clean the deposited liquid water and impurities, which can prevent the ultrasonic waves from being interfered by refraction and occlusion, and ensure the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the flow field adaptive adjustment device for the dual-channel ultrasonic gas flowmeter of the present invention;

[0018] Figure 2 It is a sectional view of the flow field adaptive adjustment device for the gas flowmeter of the present invention;

[0019] Figure 3 It is a cross-sectional view of the flow field adaptive adjustment device for the gas flowmeter of the present invention;

[0020] Figure 4 Schematic diagram of the flow field at the flow equalizing device of the present invention;

[0021] Figure 5 Schematic structural diagram of the inlet device and the flow equalizing device of the present invention;

[0022] Figure 6 Schematic structural diagram of the flow equalizing device of the present invention;

[0023] Figure 7 Schematic structural diagram of the diversion holes on the flow equalizing device of the present invention;

[0024] Figure 8 Schematic structural diagram at the upstream transducer of the present invention;

[0025] Figure 9 Schematic structural diagram at the upstream transducer after the slider is ejected of the present invention;

[0026] Figure 10 Exploded structural diagram of the actuating assembly of the present invention;

[0027] Figure 11 Schematic structural diagram of the flowmeter tube body of the present invention;

[0028] Figure 12 Schematic structural diagram of the slider of the actuating assembly of the present invention;

[0029] In the figure:

[0030] First circular tube section 1, first direction 11, second direction 12, third direction 13, second circular tube section 10;

[0031] Square tube section 2, first area 21, second area 22, drainage area 20;

[0032] First downstream transducer 3, second downstream transducer 30;

[0033] First upstream transducer 4, second upstream transducer 40, recessed area 400, limiting groove 41, channel 42;

[0034] Actuating assembly 5, slider 51, limiting part 511, groove 512, elastic body 52, sealing plate 53, electromagnetic coil 54;

[0035] Flow equalizing device 6, outlet pipe 61, drainage ring 62, first cavity 63, diversion hole 60, first diversion area 601, second diversion area 602, round hole 621, hemispherical plate 622;

[0036] Inlet device 7, inlet pipe 71, conical surface 710, support ring 72, second cavity 73;

[0037] Rectifying device 8; Detailed implementation mode

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] Next, according to the attached Figures 1 - 12 The present invention will be described in detail. The flow field adaptive adjustment device of the dual-channel ultrasonic gas flowmeter of the present invention includes a first circular pipe section 1 and a second circular pipe section 10, and a square pipe section 2 connecting the first circular pipe section 1 and the second circular pipe section 10. The square pipe section 2 is provided with a first downstream transducer 3 and a second downstream transducer 30 arranged side by side, and a first upstream transducer 4 and a second upstream transducer 40 arranged side by side; a flow straightening device 6 and an inlet device 7 are arranged in the first circular pipe section 1; the fluid enters the flow straightening device 6 from the inlet device 7, and the fluid enters the square pipe section 2 from the first circular pipe section 1 through the flow straightening device 6 to stabilize the flow field; a rectifying device 8 is arranged at the upstream positions of the first upstream transducer 4 and the second upstream transducer 40 in the square pipe section 2; an actuating assembly 5 is further arranged on one side of the first upstream transducer 4 and the second upstream transducer 40 on the square pipe section 2; the actuating assembly 5 can cover the recessed area 400 on one side of the first upstream transducer 4 and the second upstream transducer 40.

[0040] Specifically, the flow straightening device 6 of the present invention is arranged at a position close to the fluid entering the square pipe section 2 from the first circular pipe section 1. Due to the sudden change in the cross-sectional shape of the first circular pipe section 1 and the square pipe section 2, that is, from circular to square, the fluid is prone to separation and vortex formation at the corner, and the flow velocity in the corner area of the square pipe is low while the flow velocity in the center is high, which will lead to uneven velocity distribution. The rectifying device 8 in the present invention is a honeycomb structure, which consists of a plurality of densely arranged long straight holes. Refer to the attached Figure 2 And 3 , by setting the rectifying device 8, the vortices and secondary flows in the flow field can be reduced, but the problem that the flow velocity in the central area of the square pipe section 2 is high while the flow velocity in the corner area is low cannot be changed. In the present invention, a flow straightening device 6 is arranged upstream of the rectifying device 8 and at a position close to the fluid entering the square pipe section 2 from the first circular pipe section 1, which can guide the flow field in the cross-sectional area of the first circular pipe section 1 outside the cross-section of the square pipe section 2 to the corner area of the cross-section of the square pipe section 2. Refer to the attached Figure 7 , so that the flow velocities in each area of the flow field in the square pipe section 2 are evenly distributed, improving the measurement accuracy of the ultrasonic gas flowmeter.

[0041] In addition, due to factors such as the original water content in the formation, residual during exploitation, condensation during transportation, and external intrusion, liquid water is contained in natural gas. Solid impurities (such as dust) or liquid water in natural gas deposit on the inner wall of the flowmeter. If deposited in the concave area 400 as shown in Figures 8 - 11 , it will interfere with the reflection path of ultrasonic waves, resulting in signal attenuation or refraction, and reducing the measurement accuracy. When the liquid water covers the probes of the first upstream transducer 4 and the second upstream transducer 40, refraction occurs when ultrasonic waves enter and exit the water layer, and the sensor cannot effectively receive the signal, causing measurement errors or signal loss. The actuating assembly 5 in the present invention can cover the concave area 400 on one side of the first upstream transducer 4 and the second upstream transducer 40, eject the deposited liquid water and let it be carried away by the fluid. Refer to Figure 9 , which can prevent the probes of the first upstream transducer 4 and the second upstream transducer 40 from being covered by liquid water, ensuring the measurement accuracy of the ultrasonic gas flowmeter.

[0042] The inlet device 7 includes a support ring 72 located upstream and an inlet pipe 71 facing downstream; the flow equalizing device 6 includes an outlet pipe 61 facing upstream and a diversion ring 62 located downstream; a conical surface 710 is formed on the inner wall of the inlet pipe 71, and the inner diameter of the inlet pipe 71 is larger than the outer diameter of the outlet pipe 61.

[0043] The support ring 72, the inlet pipe 71 and the inner wall of the first circular pipe section 1 enclose a second cavity 73; the diversion ring 62, the outlet pipe 61 and the inner wall of the first circular pipe section 1 enclose a first cavity 63; the first cavity 63 and the second cavity 73 are arranged facing each other; after being guided by the conical surface 710 of the inlet pipe 71, part of the fluid can enter the first cavity 63, and after being reflected by the diversion ring 62, it can enter the second cavity 73 and generate a circulating flow.

[0044] Specifically, refer to Figures 2 - 4 , the inlet pipe 71 of the inlet device 7 and the outlet pipe 61 of the flow equalizing device 6 are arranged facing each other, so that after the fluid enters the first cavity 63 and the second cavity 73, it can circulate between the first cavity 63 and the second cavity 73, causing deposition of a small amount of liquid water and solid particles and other impurities in the fluid, and reducing the interference of impurities in natural gas on the downstream flowmeter. The inlet pipe 71 is of a cylindrical structure, one end of the support ring 72 is connected to the upstream end of the inlet pipe, and the other end is connected to the pipe wall of the first circular pipe section 1; the outlet pipe 61 is also of a cylindrical structure with a smaller diameter, one end of the diversion ring 62 is connected to the downstream end of the outlet pipe 61, and the other end is connected to the pipe wall of the first circular pipe section 1.

[0045] A plurality of diversion holes 60 are uniformly arranged on the diversion ring 62 of the flow equalizing device 6; the diversion holes 60 are composed of circular holes 621 and hemispherical plates 622 arranged on the circular holes 621; after the fluid passes through the circular holes 621 of the diversion holes 60, it is acted on by the hemispherical plates 622 and changes direction; and the diversion ring 62 is divided into a plurality of intervals, and the diversion directions of the diversion holes 60 in different intervals are different.

[0046] Specifically, the diversion holes 60 on the flow equalizing device 6 in the present invention can change the flow direction of the passing fluid so as to play a role in diversion and speed equalization. The cross-sectional area of the inlet pipe 71 of the device 7 is larger than the cross-sectional area of the square pipe section 2. In order to increase the flow velocity in the corner area of the square pipe section 2, the fluid passing through the outlet pipe 61 of the flow equalizing device 6 enters the central area of the square pipe section 2, and the fluid passing through the diversion ring 62 of the flow equalizing device 6 enters the corner area of the square pipe section 2. Refer to Figure 7 , and the diversion holes 60 with different orientations in different areas of the diversion ring 62 guide the passing fluid to flow towards the four corner areas of the square pipe section 2, thereby reducing the velocity difference between the central area and the corner area of the rectifying device 8.

[0047] The cross-sectional area of the outlet pipe 61 of the flow equalizing device 6 is the first area 21; the cross-sectional area of the square pipe section 2 is the second area 22; the area in the second area 22 excluding the projection of the first area 21 in the second area 22 is the diversion area 20; the diversion holes 60 in different intervals of the diversion ring 62 uniformly guide the fluid into the diversion areas 20 at different positions in the second area 22.

[0048] Specifically, as Figure 7 shown, the first area 21 is the circular cross-section of the outlet pipe 61 of the flow equalizing device 6, the second area 22 is the square cross-section of the square pipe section 2, and the areas at the four corners outside the first area 21 in the second area 22 are the diversion areas 20, that is, the corner areas of the square pipe section 2. When the fluid enters the square pipe section 2 from the first circular pipe section 1, the flow velocity in the first area 21 of the square pipe section 2 will be greater than the flow velocity in the diversion area 20. The diversion holes 60 guide more fluid into the diversion area 20, thereby increasing the flow velocity in the diversion area 20 and balancing the velocity difference between the central area and the corner area of the square pipe section 2.

[0049] The direction extending from the center of the square pipe section 2 to a right-angled vertex is the third direction 13; the vertical direction adjacent to the third direction 13 is the first direction 11; the horizontal direction adjacent to the third direction 13 is the second direction 12; the diversion holes 60 in the interval between the first direction 11 and the third direction 13 on the diversion ring 62 of the flow equalizing device 6 are arranged towards the third direction 13; the diversion holes 60 in the interval between the second direction 12 and the third direction 13 on the diversion ring 62 of the flow equalizing device 6 are arranged towards the third direction 13.

[0050] Specifically, as Figure 7 shown, the first direction 11 is the vertically upward direction, the second direction 12 is the horizontally rightward direction, and the third direction 13 is the direction that coincides with the vertex of the right angle in the upper right of the square pipe section 2. The diversion holes 60 in the interval between the first direction 11 and the third direction 13 guide the fluid into the diversion area 20 corresponding to the third direction 13, and the diversion holes 60 in the interval between the second direction 12 and the third direction 13 guide the fluid into the diversion area 20 corresponding to the third direction 13. Similarly, there are the same number of diversion holes 60 in the diversion areas 20 in other directions to introduce the fluid into them, so that the fluid passing through the diversion ring 62 of the flow equalization device 6 can be evenly guided into the diversion areas 20 in four different directions, thereby increasing the flow velocity in the diversion area 20 and balancing the velocity difference between the central area and the corner area of the square pipe section 2.

[0051] The opening of the hemispherical plate 622 on the round hole 621 of the diversion hole 60 in the interval between the first direction 11 and the third direction 13 faces the third direction 13; the opening of the hemispherical plate 622 on the round hole 621 of the diversion hole 60 in the interval between the second direction 12 and the third direction 13 faces the third direction 13; no hemispherical plate 622 is provided on the round hole 621 of the diversion hole 60 distributed along the third direction 13.

[0052] Specifically, see Figure 7 , the third direction 13 is the four directions towards the four right angles of the cross-section of the square pipe section 2, and no hemispherical plate 622 is provided on the round hole 621 of the diversion hole 60 distributed in these directions. The hemispherical plate 622 can be formed by stamping the excess material by a punch when punching the round hole 621, and the manufacturing process is simple and practical.

[0053] The first downstream transducer 3, the second downstream transducer 30, the first upstream transducer 4 and the second upstream transducer 40 are inclined; the ultrasonic waves are emitted from the first upstream transducer 4 and the second upstream transducer 40 and are received by the first downstream transducer 3 and the second downstream transducer 30 along a straight path; the straight path of the ultrasonic waves is perpendicular to the transmitting / receiving end face of the transducer; the transmitting / receiving end face of the transducer forms a recessed area 400 with the pipe wall of the square pipe section 2; a slider 51 of the actuating assembly 5 is arranged in the recessed area 400.

[0054] The inclined transducer can obtain a longer measurement path in a smaller volume, thereby improving the measurement accuracy of the ultrasonic flowmeter. To reduce the refraction of ultrasonic waves, it is necessary to make the moving path of the ultrasonic waves perpendicular to the transmitting / receiving end face of the transducer. Therefore, an indentation area 400 is inevitably formed at the transmitting / receiving end face of the transducer and the pipe wall of the square pipe section 2. When liquid water or other natural gas impurities are deposited in the indentation area 400, the passing ultrasonic waves will be refracted or blocked, affecting the measurement of the ultrasonic flowmeter.

[0055] The slider 51 of the actuating assembly 5 is connected to the sealing plate 53 through an elastomer 52; an electromagnetic coil 54 is installed outside the sealing plate 53, and the slider 51 is driven to move and reset through the electromagnetic coil 54 and the elastomer 52.

[0056] Specifically, the pipe wall of the square pipe section 2 and the sealing plate 53 in the present invention are made of non-magnetic materials, the slider 51 is made of magnetic materials, and the electromagnetic coil 54 generates a thrust on the slider 51 after being energized. The slider 51 covers the indentation area 400 and pushes out the deposited liquid water / other impurities. At this time, the slider 51 will temporarily block the ultrasonic waves emitted by the transducer. See the appendix Figure 9 , and the fluid is used to remove the pushed liquid water / impurities. After the electromagnetic coil 54 is de-energized, the elastomer 52 is used to restore the slider 51 to its initial position. The braking assembly 5 of the present invention uses the electromagnetic coil 54 for non-contact driving, and can use the sealing plate 53 to achieve better sealing, preventing the leakage of natural gas at the actuating mechanism.

[0057] The slider 51 slides along the channel 42 in the square pipe section 2, and limiting grooves 41 are provided on both sides of the channel 42; limiting portions 511 are provided on both sides of the slider 51, and the limiting portions 511 cooperate with the limiting grooves 41; a groove 512 is also provided on the slider 51.

[0058] Specifically, the channel 42 is perpendicular to the ultrasonic wave path generated by the first upstream transducer 4. See the appendix Figure 10 , the limiting grooves 41 and the limiting portions 511 on both sides of the channel 42 limit the pushing position of the slider 51 and the original position after reset. When the slider 51 is in the original position, the groove 512 on it forms the ultrasonic wave emission channel of the transducer.

[0059] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A flow field adaptive adjustment device for a dual-channel ultrasonic gas flowmeter, comprising a first circular pipe section (1) and a second circular pipe section (10), as well as a square pipe section (2) connecting the first circular pipe section (1) and the second circular pipe section (10), characterized in that: On the square pipe section (2), a first downstream transducer (3) and a second downstream transducer (30) are arranged side by side, and a first upstream transducer (4) and a second upstream transducer (40) are arranged side by side; A flow straightening device (6) and an inlet device (7) are arranged in the first circular pipe section (1); The fluid enters the flow straightening device (6) from the inlet device (7), and the fluid enters the square pipe section (2) from the first circular pipe section (1) through the flow straightening device (6) to stabilize the flow field; A rectifying device (8) is arranged at the upstream position of the first upstream transducer (4) and the second upstream transducer (40) in the square pipe section (2); An actuating component (5) is further arranged on one side of the first upstream transducer (4) and the second upstream transducer (40) on the square pipe section (2); The actuating component (5) can cover the recessed area (400) on one side of the first upstream transducer (4) and the second upstream transducer (40); The flow straightening device (6) includes an outlet pipe (61) facing upstream and a drainage ring (62) located downstream; The cross-sectional area of the outlet pipe (61) of the flow straightening device (6) is a first area (21); The cross-sectional area of the square pipe section (2) is a second area (22); The area in the second area (22) excluding the projection of the first area (21) in the second area (22) is the drainage area (20); The diversion holes (60) in different intervals of the drainage ring (62) evenly guide the fluid into the drainage areas (20) at different positions in the second area (22).

2. The flowmeter flow field adaptive adjustment device according to claim 1, characterized in that: The inlet device (7) includes a support ring (72) located upstream and an inlet pipe (71) facing downstream; The inner wall of the inlet pipe (71) forms a conical surface (710), and the inner diameter of the inlet pipe (71) is larger than the outer diameter of the outlet pipe (61).

3. The flowmeter flow field adaptive adjustment device according to claim 2, characterized in that: The support ring (72), the inlet pipe (71) and the inner wall of the first circular pipe section (1) enclose a second cavity (73); The drainage ring (62), the outlet pipe (61) and the inner wall of the first circular pipe section (1) enclose a first cavity (63); The first cavity (63) and the second cavity (73) are arranged facing each other; After being guided by the conical surface (710) of the inlet pipe (71), part of the fluid can enter the first cavity (63), and after being reflected by the drainage ring (62), it can enter the second cavity (73) and generate a circulating flow.

4. The flowmeter flow field adaptive adjustment device according to claim 3, characterized in that: A plurality of diversion holes (60) are evenly arranged on the drainage ring (62) of the flow straightening device (6); The diversion hole (60) is composed of a round hole (621) and a hemispherical plate (622) provided on the round hole (621); After the fluid passes through the round hole (621) of the diversion hole (60), it is affected by the hemispherical plate (622) and changes direction; And the diversion ring (62) is divided into multiple intervals, and the diversion directions of the diversion holes (60) in different intervals are different.

5. The flowmeter flow field adaptive adjustment device according to claim 4, characterized in that: The direction extending from the center of the square pipe section (2) to a right-angled vertex is the third direction (13); The vertical direction adjacent to the third direction (13) is the first direction (11); The horizontal direction adjacent to the third direction (13) is the second direction (12); The diversion holes (60) in the interval between the first direction (11) and the third direction (13) on the diversion ring (62) of the flow equalizing device (6) are arranged facing the third direction (13); The diversion holes (60) in the interval between the second direction (12) and the third direction (13) on the diversion ring (62) of the flow equalizing device (6) are arranged facing the third direction (13).

6. The flowmeter flow field adaptive adjustment device according to claim 5, characterized in that: The opening of the hemispherical plate (622) on the round hole (621) of the diversion hole (60) in the interval between the first direction (11) and the third direction (13) faces the third direction (13); The opening of the hemispherical plate (622) on the round hole (621) of the diversion hole (60) in the interval between the second direction (12) and the third direction (13) faces the third direction (13); No hemispherical plate (622) is provided on the round hole (621) of the diversion hole (60) distributed along the third direction (13).

7. The flowmeter flow field adaptive adjustment device according to claim 6, characterized in that: The first downstream transducer (3), the second downstream transducer (30), the first upstream transducer (4) and the second upstream transducer (40) are inclined; After the ultrasonic waves start from the first upstream transducer (4) and the second upstream transducer (40), they are received by the first downstream transducer (3) and the second downstream transducer (30) along a straight path; The straight path of the ultrasonic wave is perpendicular to the transmitting / receiving end face of the transducer; A recessed area (400) is formed between the transmitting / receiving end face of the transducer and the pipe wall of the square pipe section (2); A slider (51) of the actuating component (5) is arranged in the recessed area (400).

8. The flowmeter flow field adaptive adjustment device according to claim 7, characterized in that: The slider (51) of the actuating component (5) is connected to the sealing plate (53) through an elastic body (52); An electromagnetic coil (54) is installed on the outer side of the sealing plate (53), and the slider (51) is driven to move and reset through the electromagnetic coil (54) and the elastic body (52).

9. The flowmeter flow field adaptive adjustment device according to claim 8, characterized in that: The slider (51) slides along the channel (42) in the square pipe section (2), and limiting grooves (41) are arranged on both sides of the channel (42); Limiting parts (511) are arranged on both sides of the slider (51), and the limiting parts (511) are matched with the limiting grooves (41); A groove (512) is further arranged on the slider (51).

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