Gas flow velocity measuring device

Abstract

The invention discloses a gas flow velocity measuring device which comprises a cover plate detachably connected with a measuring section, a vertical plate is fixed on the cover plate, a guide pipe is fixed between the vertical plate and the cover plate, a lifting mechanism is detachably connected to the vertical plate, a mounting plate is detachably connected to the moving end of the lifting mechanism, and the mounting plate is detachably connected to the moving end of the lifting mechanism. An S-shaped pitot tube is fixed on the mounting plate, the S-shaped pitot tube penetrates through the guide tube and extends into the measuring section, a sealing ring is arranged between the S-shaped pitot tube and the guide tube, and the plane where a total pressure tube and a static pressure tube of the S-shaped pitot tube are located is parallel to the flowing direction of a medium in the measuring section. Compared with the prior art, the vertical moving distance of the S-shaped pitot tube is controllable through the lifting mechanism and the guide tube, the S-shaped pitot tube cannot rotate in the moving process, and the total pressure tube and the static pressure tube of the S-shaped pitot tube are small in tube diameter and small in flow field interference, so that the uniformity and the stability of the flow velocity of the section of the measurement section are accurately measured.

Description

Technical Field

[0001] The present invention relates to the technical field of gas flow measurement, and in particular to a gas flow velocity measuring device. Background Art

[0002] When a wind tunnel is operating, air is rectified before entering the measurement section, forming a uniform and stable flow field. The anemometer being tested is simultaneously installed in the measurement section, and its reading is compared with the standard wind speed to determine the indication error. To ensure accurate measurement results, the uniformity and stability of the wind tunnel flow field are crucial. Poor uniformity can lead to significant differences in the readings of the anemometer being tested at different installation locations; poor stability can also lead to significant differences in measurement results at different times. Therefore, in daily work, it is necessary to evaluate the wind tunnel's rectification results, specifically to accurately measure the uniformity and stability of the cross-sectional flow velocity.

[0003] According to the relevant technical specifications, it is necessary to measure the flow velocity at different points in the vertical cross section of the measuring section. Common measuring equipment includes Pitot tubes, thermal anemometers and laser Doppler velocimeters (LDVs). The diameter of the measuring rod of the thermal anemometer is generally 10 mm. In wind tunnels with smaller cross-sectional areas, its own interference with the flow field cannot be ignored, so its use scenarios are limited. Although the LDV has high measurement accuracy, fast response and does not interfere with the flow field, the laser beam must penetrate the wall of the tunnel to form a measuring body at the measuring point during measurement. It is required that at least one side of the measuring section be made of transparent material for transmitting the laser, which increases the difficulty of design and processing. In addition, the refractive index of the transparent material is different from that of the air. The measuring point will deviate from the position due to the refraction of the laser beam, and a large amount of correction calculations are required when processing the results. Summary of the Invention

[0004] The present invention provides a gas flow velocity measuring device, which is used to solve the problem that thermal anemometers and laser Doppler velocimeters (LDVs) have deficiencies in flow velocity measurement.

[0005] The present invention provides a gas flow rate measuring device, comprising a cover plate detachably connected to a measuring section, a vertical plate fixed on the cover plate, a guide tube fixed between the vertical plate and the cover plate, a lifting mechanism detachably connected to the vertical plate, a mounting plate detachably connected to the movable end of the lifting mechanism, an S-shaped pitot tube fixed on the mounting plate, the S-shaped pitot tube passing through the guide tube and extending into the measuring section, a sealing ring provided between the S-shaped pitot tube and the guide tube, and the planes on which the total pressure tube and the static pressure tube of the S-shaped pitot tube are located are parallel to the flow direction of the medium in the measuring section.

[0006] Preferably, the S-type Pitot tube includes a fixed tube, which is fixed on the mounting plate. The fixed tube is slidably connected to the guide tube, the sealing ring is arranged between the fixed tube and the guide tube, and the total pressure tube and the static pressure tube are respectively inserted into the fixed tube.

[0007] Preferably, the bottoms of the total pressure pipe and the static pressure pipe are both provided with inclined surfaces, and the two inclined surfaces are arranged opposite to each other.

[0008] Preferably, the angle between the inclined plane and the horizontal plane is 45°.

[0009] Preferably, the lifting mechanism is a guide rail slide, the mounting plate and the slider of the guide rail slide are fixed by bolts, and the guide rail slide is fixed to the vertical plate by bolts.

[0010] Preferably, there are multiple guide tubes distributed along the width direction of the cover plate, and the vertical plate is provided with two strip holes from top to bottom, and bolts pass through the adjustment holes to fix the vertical plate to the guide rail slide.

[0011] Preferably, a sealing gasket is provided at the lower end of the cover plate, and the length and width of the sealing gasket are respectively smaller than the length and width of the cover plate.

[0012] Preferably, a horizontal plate is fixed on the vertical plate, the guide tube is fixedly connected to the horizontal plate, and the bottom of the guide rail slide is in contact with the horizontal plate.

[0013] Preferably, a reinforcing plate is provided on the vertical plate, and the strip-shaped hole below passes through the reinforcing plate.

[0014] Preferably, the total pressure pipe and the static pressure pipe are both made of stainless steel, and the fixing pipe and the mounting plate are both made of plastic.

[0015] Compared with existing technologies, the present invention is simple overall, with the device divided into several parts, making it easy to disassemble and manufacture. The bracket and S-type pitot tube can be adjusted to different measurement section specifications. The lifting mechanism and guide tube ensure that the vertical movement distance of the S-type pitot tube is controllable and the S-type pitot tube does not rotate during movement. In addition, the total pressure pipe and static pressure pipe of the S-type pitot tube have small diameters, which minimize interference with the flow field, thereby achieving accurate measurement of the uniformity and stability of the flow velocity across the measurement section. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 This is a structural diagram of the present invention without the lifting mechanism;

[0019] Figure 3 It is a partial structural schematic diagram of the present invention;

[0020] Figure 4 This is a schematic structural diagram of an S-type pitot tube of the present invention;

[0021] Figure 5 It is a cross-sectional schematic diagram of the S-type pitot tube of the present invention.

[0022] Reference numerals:

[0023] 1. Measuring section, 2. Cover plate, 3. Vertical plate, 4. Guide tube, 5. Lifting mechanism, 6. Mounting plate, 7. S-type Pitot tube, 8. Sealing gasket, 9. Horizontal plate, 31. Strip hole, 71. Total pressure tube, 72. Static pressure tube, 73. Fixed tube, 100. Inclined surface, 200. Reinforcement plate. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0025] Refer to the attached Figure 1 The present embodiment provides a gas flow rate measuring device, comprising a cover plate 2 detachably connected to a measuring section 1, a vertical plate 3 being fixed to the upper end of the cover plate 2, a guide tube 4 being fixed between the vertical plate 3 and the cover plate 2, a lifting mechanism 5 being detachably connected to the vertical plate 3, a mounting plate 6 being detachably connected to the movable end of the lifting mechanism 5, an S-shaped pitot tube 7 being fixed to the mounting plate 6, the S-shaped pitot tube 7 passing through the guide tube 4 and extending into the measuring section 1, a sealing ring being provided between the S-shaped pitot tube 7 and the guide tube 4, as shown in the attached drawings. Figure 4The plane where the total pressure pipe 71 and static pressure pipe 72 of the S-type pitot tube 7 are located is parallel to the flow direction of the medium in the measuring section 1, and the total pressure pipe 71 and static pressure pipe 72 are both perpendicular to the measuring section 1. The cover plate 2, the riser 3 and the guide tube 4 constitute a bracket. The device in the present invention is divided into three parts: the S-type pitot tube 7, the lifting mechanism 5 and the bracket. The bracket is integrally printed using 3D printing technology and can be adjusted in size according to different specifications of the measuring section 1. The lifting mechanism 5 drives the mounting plate 6 to move up and down, driving the S-type pitot tube 7 to slide up and down along the guide tube 4, thereby adjusting the horizontal position of the total pressure pipe 71 and static pressure pipe 72 in the measuring section 1. During the lifting and lowering process of the S-type pitot tube 7, the lifting mechanism 5 and the guide tube 4 cooperate to ensure that the angle of the plane where the total pressure pipe 71 and static pressure pipe 72 are located is consistent with the flow direction of the medium, and will not be tilted or deflected due to changes in the position of the pressure tapping hole. Secondly, the flow velocity measurement position can be accurately measured by the lifting mechanism 5, ensuring that the measurement point position is accurately controllable. Third, the total pressure tube 71 and the static pressure tube 72 of the S-type pitot tube 7 have small diameters, which have little interference on the flow field and can adapt to the measurement of small-sized flow fields.

[0026] An embodiment of the S-type Pitot tube 7: The S-type Pitot tube 7 includes a fixed tube 73, which is fixed on the mounting plate 6. The fixed tube 73 is slidably connected to the guide tube 4. A sealing ring is provided between the fixed tube 73 and the guide tube 4. The total pressure tube 71 and the static pressure tube 72 are respectively inserted into the fixed tube 73, and then the gap between the total pressure tube 71 and the fixed tube 73 is sealed, and the gap between the static pressure tube 72 and the fixed tube 73 is sealed.

[0027] As another embodiment of the present invention: Figure 5 The bottoms of both the total pressure pipe 71 and the static pressure pipe 72 are provided with inclined surfaces 100, which face each other. The inclined surface 100 of the total pressure pipe 71 faces the incoming medium, while the inclined surface 100 of the static pressure pipe 72 faces the outgoing medium. This structural design ensures that the total pressure pipe 71 and the static pressure pipe 72 remain vertical, minimizing disturbance to the flow field.

[0028] Specifically, the angle between the inclined plane 100 and the horizontal plane is 45°.

[0029] As another embodiment of the present invention: the lifting mechanism 5 is a guide rail slide, the mounting plate 6 and the slider of the guide rail slide are fixed by bolts, the guide rail slide and the vertical plate 3 are fixed by bolts, and the slide slides up and down along the guide rail to drive the mounting plate 6 to move up and down.

[0030] As another embodiment of the present invention: Figure 2-3There are multiple guide tubes 4 distributed along the width of the cover plate 2. There are five guide tubes 4, one for each of the five test positions A, B, C, D, and E. The riser 3 is provided with two strip holes 31 from top to bottom. Bolts pass through the strip holes 31 to secure the riser 3 to the guide rail slide. The bolts can move laterally within the strip holes 31, allowing the lifting mechanism 5 to flexibly adjust its installation position according to the five test positions A, B, C, D, and E.

[0031] As another embodiment of the present invention: a sealing gasket 8 is provided at the lower end of the cover plate 2, the length and width of the sealing gasket 8 are respectively smaller than the length and width of the cover plate 2, and the sealing gasket 8 is used to seal the gap between the cover plate 2 and the measuring section 1. The cover plate 2 and the measuring section 1 are fixed by bolts.

[0032] As another embodiment of the present invention: a horizontal plate 9 is fixed on the vertical plate 3, the guide tube 4 is fixedly connected to the horizontal plate 9, the bottom of the guide rail slide is in contact with the horizontal plate 9, the horizontal plate 9 is part of the bracket, and the horizontal plate 9 is used to provide support for the guide rail slide.

[0033] As another embodiment of the present invention: a reinforcing plate 200 is provided on the vertical plate 3, and the strip hole 31 below passes through the reinforcing plate 200. The reinforcing plate 200 is arranged in the middle position of the vertical plate 3 to improve the structural strength there.

[0034] As another embodiment of the present invention: the total pressure pipe 71 and the static pressure pipe 72 are both made of stainless steel, the fixed pipe 73 and the mounting plate 6 are both made of plastic, and the fixed pipe 73 and the mounting plate 6 are integrally printed using 3D printing technology.

[0035] As another embodiment of the present invention, the outer diameters of the total pressure pipe 71 and the static pressure pipe 72 are 3 mm.

[0036] Specifically, measurement section 1 has a rectangular cross-section of 200 mm x 200 mm, and both total pressure tube 71 and static pressure tube 72 are 220 mm long. The S-type pitot tube 7 has a range of motion of 200 mm within measurement section 1, with test points taken every 5 mm in the height direction. The test data for the S-type pitot tube 7 within measurement section 1 is shown in Table 1.

[0037] Table 1 Pitot tube wind tunnel flow field measurement data at 10 m / s

[0038]

[0039]

[0040]

[0041] The flow rate v in the above table is calculated by the following formula:

[0042]

[0043] Where:

[0044] ρ is the air density, in kg / m 3 ;

[0045] P is the indication of the S-type Pitot tube, in Pa.

[0046] As shown in Table 1, the S-type Pitot tube in this device can accurately measure the uniformity and stability of the flow velocity in the measurement section, thereby realizing the evaluation of the rectification effect of the wind tunnel.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A gas flow rate measuring device, characterized in that: It includes a cover plate detachably connected to the measuring section, a vertical plate is fixed on the cover plate, a guide tube is fixed between the vertical plate and the cover plate, a lifting mechanism is detachably connected to the vertical plate, a movable end of the lifting mechanism is detachably connected to a mounting plate, an S-shaped pitot tube is fixed on the mounting plate, the S-shaped pitot tube passes through the guide tube and extends into the measuring section, a sealing ring is provided between the S-shaped pitot tube and the guide tube, and the plane where the total pressure pipe and the static pressure pipe of the S-shaped pitot tube are located is parallel to the flow direction of the medium in the measuring section.

2. The gas flow rate measuring device according to claim 1, characterized in that: The S-type Pitot tube includes a fixed tube, which is fixed on a mounting plate. The fixed tube is slidably connected to a guide tube. The sealing ring is arranged between the fixed tube and the guide tube. The total pressure tube and the static pressure tube are respectively inserted into the fixed tube.

3. The gas flow rate measuring device according to claim 2, characterized in that: The bottoms of the total pressure pipe and the static pressure pipe are both provided with inclined surfaces, and the two inclined surfaces are arranged opposite to each other.

4. The gas flow rate measuring device according to claim 3, characterized in that: The angle between the inclined plane and the horizontal plane is 45°.

5. The gas flow rate measuring device according to claim 4, characterized in that: The lifting mechanism is a guide rail slide, the mounting plate and the slider of the guide rail slide are fixed by bolts, and the guide rail slide is fixed to the vertical plate by bolts.

6. The gas flow rate measuring device according to claim 5, characterized in that: There are multiple guide tubes distributed along the width direction of the cover plate. The vertical plate is provided with two strip holes from top to bottom. Bolts pass through the adjustment holes to fix the vertical plate to the guide rail slide.

7. The gas flow rate measuring device according to claim 6, characterized in that: A sealing gasket is provided at the lower end of the cover plate, and the length and width of the sealing gasket are respectively smaller than the length and width of the cover plate.

8. The gas flow rate measuring device according to claim 7, characterized in that: A horizontal plate is fixed on the vertical plate, the guide tube is fixedly connected to the horizontal plate, and the bottom of the guide rail slide is in contact with the horizontal plate.

9. The gas flow rate measuring device according to claim 8, characterized in that: A reinforcing plate is provided on the vertical plate, and the strip-shaped hole below passes through the reinforcing plate.

10. The gas flow rate measuring device according to claim 9, characterized in that: The total pressure pipe and the static pressure pipe are both made of stainless steel, and the fixing pipe and the mounting plate are both made of plastic.

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