Magnus device and method for measuring speed deviation and air volume of large-section air duct

Abstract

The invention relates to the technical field, and provides a Magnus device and method for measuring the speed deviation and the air volume of a large-section air duct, and the Magnus device comprises a plurality of hollow Magnus rollers which are arranged along the section of the air duct in an array manner, and the plurality of Magnus rollers rotate in the direction perpendicular to the air duct. Closed slideways are respectively arranged above and below the Magnus rollers in the same horizontal direction, the top and the bottom of each Magnus roller are respectively connected with an upper connecting block and a lower connecting block, a motor is arranged in each lower connecting block, and an output shaft of each motor is rotatably connected with the corresponding Magnus roller through a roller connecting rod; the end, away from the Magnus roller, of the roller connecting rod extends out of the Magnus roller and is connected with a motor output shaft, and a displacement measuring mechanism or a pressure measuring mechanism is arranged in the closed sliding way on one side of the Magnus roller. According to the scheme, the wind speed distribution condition of the section at any moment under different wind volumes can be evaluated at any time, the accuracy of original data acquisition is improved, and the method has practical significance for researching wind channel flow field distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of wind speed and wind direction, and specifically to a Magnus device and method for measuring velocity deviation and air volume in a large-section wind duct. Background Art

[0002] Due to the large cross-section of the air duct, the wind speed distribution of the cross-section is very uneven. The currently commonly used matrix air volume measurement device can only measure the air volume value, and cannot measure the wind speed in different areas of the cross-section, so it is impossible to effectively evaluate the wind speed distribution of the cross-section. Conventional manual measurement requires opening a measurement hole in the corresponding air duct, inserting backrest tubes of different depths and using a micromanometer to perform manual point measurement. The disadvantage of this method is that the cross-sectional wind speed is in a process of rapid fluctuation and change, and the reading of the micromanometer is also constantly changing. Therefore, the dynamic pressure value read is greatly affected by human subjectivity, and the wind speed of the original measured point may have changed during the process of inserting the backrest tube or changing the measuring point. Therefore, the data obtained by this method is often quite different from the actual situation, and it is impossible to make an accurate assessment of the cross-section and air volume value of the air duct, which affects the subsequent data analysis. Summary of the invention

[0003] In order to solve the problems existing in the background technology, the present invention proposes a Magnus device and method for measuring the velocity deviation and air volume of a large-section wind duct, which can evaluate the wind speed distribution of the cross-section at any time under different air volumes, improve the accuracy of raw data acquisition, and have practical significance for studying the flow field distribution of the wind duct.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following scheme: a Magnus device for measuring velocity deviation and air volume of a large-section air duct, the device is arranged horizontally, and the device includes a plurality of hollow Magnus rollers arranged along the cross-section array of the air duct, the plurality of Magnus rollers rotate in a direction perpendicular to the air duct, and closed slideways are respectively provided above and below the Magnus rollers in the same horizontal direction, and each of the Magnus rollers is respectively connected to an upper connecting block and a lower connecting block at the top and bottom, and the upper connecting block and the lower connecting block are respectively arranged in the closed slideways at the upper and lower parts, and a motor is arranged in the lower connecting block, and the output shaft of the motor is rotationally connected to the Magnus roller through a roller connecting rod, and the roller connecting rod is arranged in the Magnus roller, and one end of the roller connecting rod away from the Magnus roller extends out of the Magnus roller and is connected to the output shaft of the motor, and a displacement measuring mechanism or a pressure measuring mechanism is provided in the closed slideway on one side of the Magnus roller.

[0005] Furthermore, the displacement measuring mechanism includes a compression spring and an indicator line, the upper connecting block is fixedly connected to the Magnus roller, the upper connecting block and the lower connecting block are respectively slidably connected to the upper and lower closed slideways, two compression springs are provided on the same side, one ends of the two compression springs are respectively connected to the upper connecting block and the lower connecting block, the other ends of the two compression springs are fixed to the inner wall of the closed slideway, the indicator line is provided on the same side as the compression spring, one end of the indicator line is fixed to the upper connecting block or the lower connecting block, the other end of the indicator line extends out of the air duct, and the indicator line is provided with a scale.

[0006] Furthermore, when the wind direction of the air duct is in the windward direction relative to the air duct cross-section, the compression spring and the indicator line are arranged on the left side of the Magnus roller to drive the Magnus roller to rotate counterclockwise; when the wind direction of the air duct is in the leeward direction relative to the air duct cross-section, the compression spring and the indicator line are arranged on the right side of the Magnus roller to drive the Magnus roller to rotate clockwise.

[0007] Further, the pressure measuring mechanism includes a pressure sensor, one end of the upper connecting block and the lower connecting block away from the Magnus roller is fixed to the inner wall of the closed slideway, and the upper connecting block is rotatably connected to the Magnus roller through a bearing;

[0008] When the wind direction of the air duct is in the windward direction relative to the air duct cross section, the pressure sensor is fixed in any one of the upper and lower closed slideways close to the left side of the Magnus roller, driving the Magnus roller to rotate counterclockwise; when the wind direction of the air duct is in the leeward direction relative to the air duct cross section, the pressure sensor is fixed in any one of the upper and lower closed slideways close to the right side of the Magnus roller, driving the Magnus roller to rotate clockwise; the pressure sensor is electrically connected to a controller.

[0009] Furthermore, the motor is connected to a power supply, and the device is arranged at 3-5 times the equivalent diameter upstream or downstream of the elbow.

[0010] Furthermore, when the air duct is a high-temperature air duct, the device is made of Q345B, and when the air duct is a normal-temperature air duct, the device is made of Q235 or PVC plastic lightweight material.

[0011] The method for measuring velocity deviation of a large cross-section air duct comprises the following steps:

[0012] Step A1, selecting a plurality of cross sections at intervals along the length direction of the air duct, and arranging the Magnus device in each cross section;

[0013] Step A2, according to the wind direction in the air duct, a displacement measuring mechanism is arranged on the left or right side of the Magnus drum, and at the same time, the Magnus drum is driven to rotate counterclockwise or clockwise according to the wind direction in the air duct. At this time, the Magnus drum is subjected to pressure to the left or right, so that the compression spring is deformed, and at the same time, the indicator line is displaced. The displacement value of the indicator line is obtained according to the scale change on the indicator line, and the displacement value of the indicator line is used to represent the air duct velocity value of the sampling point in the area where the Magnus drum is located;

[0014] Step A3, obtaining the indicator line displacement values ​​of all Magnus rollers in the cross section in the manner described in step A2, and then calculating the average indicator line displacement value, and also using the indicator line average displacement value to represent the average velocity value of the air duct in the cross section;

[0015] Step A4: Substitute the displacement value of the indicator line at the sampling point in step A3 and the average displacement value of the indicator line of the cross section into the calculation formula Get the velocity standard deviation, where The average displacement of the indicator line represents the average velocity of the wind duct in this section, V J The displacement of the sampling point indicator line represents the speed of the sampling point J, S is the speed standard deviation, and n is the number of partitions; the calculation formula is Get the relative standard deviation rate, where S is the speed standard deviation, is the average velocity of the air duct in this section; CV is the relative standard deviation rate.

[0016] The method for measuring the air volume of a large cross-section air duct comprises the following steps:

[0017] Step B1, selecting a plurality of cross sections at intervals along the length direction of the air duct, and arranging the Magnus device in each cross section;

[0018] Step B2, according to the wind direction in the air duct, a pressure sensor is arranged in the closed slideway on the left or right side of the Magnus roller, and at the same time, the Magnus roller is driven to rotate counterclockwise or clockwise according to the wind direction in the air duct. At this time, the Magnus roller is subjected to pressure to the left or right, and a pressure value, i.e., the pressure value of the Magnus roller, is obtained through the pressure sensor, and the pressure sensor converts the force condition of the Magnus roller into an electrical signal in real time and transmits it to the controller;

[0019] Step B3, calculating the air duct velocity value of the sampling point in the area where the Magnus roller is located through the pressure value of the Magnus roller;

[0020] Step B4, obtaining the air duct velocity values ​​of the sampling points in the area where all Magnus rollers of the cross section are located in the manner described in step B3, and then calculating the average air duct velocity value of the cross section;

[0021] Step B5, substituting the average duct velocity value obtained in step B4 into the calculation formula Q=VA to obtain the air volume of the duct cross section, wherein Q is the air volume, V is the average duct velocity, and A is the duct cross-sectional area.

[0022] Furthermore, the method for calculating the fluid velocity value in the area where the Magnus cylinder is located by using the pressure value of the Magnus cylinder is as follows: firstly, the radius and the angular velocity of the Magnus cylinder are measured and substituted into the calculation formula Γ=2πr 2 w is used to obtain the circulation of the Magnus cylinder, where Γ is the circulation, r is the radius of the Magnus cylinder, and w is the angular velocity of the Magnus cylinder. Secondly, the pressure value of the Magnus cylinder and the circulation of the Magnus cylinder are substituted into the calculation formula L = -ρV ∞ The fluid velocity value in the area where the Magnus roller is located is obtained as the air duct velocity value of the sampling point, where ρ is the fluid density, V is the fluid velocity, Γ is the circulation, and L is the pressure.

[0023] The beneficial effects of the present invention are as follows: This solution utilizes the principle that the rotating Magnus roller is subjected to lateral force in the fluid, converts the wind speed that cannot be directly measured into force and measures it to characterize the wind speed. The wind speed distribution of the cross section at any time under different air volumes can be evaluated at any time, which improves the accuracy of the original data acquisition and has practical significance for studying the distribution of the air duct flow field. The Magnus device with a displacement measuring mechanism can measure the velocity deviation of the large cross-section air duct, and characterize the air duct velocity value of the sampling point in the area where the Magnus roller is located by the displacement value of the indicator line. There is no need to convert the displacement into speed, and data acquisition is convenient. In addition, the displacement measuring mechanism can be replaced with a pressure measuring mechanism, which is converted into an electrical signal in real time and transmitted to the controller, and can be converted into regional wind speed according to the formula, and then the air volume of the air duct can be calculated. The entire device structure is simple and easy to operate, and the data is timely, which can make an accurate assessment of the air duct cross-section velocity deviation and air volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the present invention;

[0025] Figure 2 The figure is a schematic diagram of the force condition of a single Magnus roller provided with a displacement measuring mechanism according to an embodiment of the present invention. The numbers in the figure are: 1, air duct section; 2, Magnus roller; 3, indicator line; 4, closed slideway; 5, compression spring; 6, power supply; 7, motor; 8, roller connecting rod; 9, upper connecting block; 10, lower connecting block. DETAILED DESCRIPTION

[0026] In order to make the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the given embodiment is only one implementation method and does not represent all embodiments.

[0027] Embodiment 1

[0028] Combination Figure 1-Figure 2 This embodiment provides a Magnus device for measuring velocity deviation and air volume of a large cross-section wind duct. The device is arranged horizontally, and the airflow should not have reverse backflow at the arrangement position. The device is arranged 3-5 times the equivalent diameter upstream or downstream of the elbow. The conventional wind duct section 1 is 3*3, 4*4 or 3*5. The size of the wind duct section 1 is used as an array unit, and multiple array units are arranged at intervals along the length direction of the wind duct. The wind speed distribution of each cross section at any time under different air volumes can be evaluated at any time, which improves the accuracy of the original data acquisition and is practical for studying the distribution of the wind duct flow field.

[0029] The device includes a plurality of hollow Magnus rollers 2 arranged in an array along the air duct cross section 1, the plurality of Magnus rollers 2 rotate in a direction perpendicular to the air duct, closed slideways 4 are respectively provided above and below the Magnus rollers 2 in the same horizontal direction, the top and bottom of each Magnus roller 2 are respectively connected with an upper connecting block 9 and a lower connecting block 10, the upper connecting block 9 and the lower connecting block 10 are respectively arranged in the closed slideways 4 at the upper and lower parts, a motor 7 is provided in the lower connecting block 10, the output shaft of the motor 7 is rotationally connected to the Magnus roller 2 through a roller connecting rod 8, the roller connecting rod 8 is arranged in the Magnus roller 2, one end of the roller connecting rod 8 away from the Magnus roller 2 extends out of the Magnus roller 2 and is connected to the output shaft of the motor 7, a displacement measuring mechanism or a pressure measuring mechanism is provided in the closed slideway 4 on one side of the Magnus roller 2, and the motor 7 is connected to a power supply 6. The Magnus device with a displacement measuring mechanism can measure the velocity deviation of a large cross-section air duct, and the Magnus device with a pressure measuring mechanism can measure the air volume of a large cross-section air duct. The device has no sampling holes, which avoids the risk of pipe blocking of conventional matrix measuring devices and other types of measuring devices, and can be used in air ducts or flues with relatively large dust content. The Magnus drum 2 in this embodiment is cylindrical and hollow. In order to reduce the deadweight of the drum, the height and diameter of the Magnus drum 2 are reasonably selected according to the size of the air duct.

[0030] Specifically, the displacement measuring mechanism includes a compression spring 5 and an indicator line 3. The upper connecting block 9 is fixedly connected to the Magnus roller 2. The upper connecting block 9 and the lower connecting block 10 are respectively slidably connected to the upper and lower closed slideways 4. Two compression springs 5 ​​are arranged on the same side. One end of the two compression springs 5 ​​is respectively connected to the upper connecting block 9 and the lower connecting block 10. The other ends of the two compression springs 5 ​​are fixed to the inner wall of the closed slideway 4. The indicator line 3 is arranged on the same side as the compression spring 5. One end of the indicator line 3 is fixed to the upper connecting block 9 or the lower connecting block 10. The other end of the indicator line 3 extends out of the air duct. The indicator line 3 is provided with a scale. It should be understood that the indicator line 3 can be provided on both the upper connecting block 9 and the lower connecting block 10, but as a preferred embodiment, Figure 1-2 The indicator line 3 is selected to be arranged on the lower connecting block 10, but is not limited to that shown in the figure. The sliding friction coefficient between the closed slideway 4 and the upper connecting block 9 and the lower connecting block 10 is as small as possible, and the compression spring 5 can be directly welded to the closed slideway 4.

[0031] In this embodiment, when the wind direction of the air duct is in the windward direction relative to the air duct cross section 1, the compression spring 5 and the indicator line 3 are arranged on the left side of the Magnus roller 2 to drive the Magnus roller 2 to rotate counterclockwise; when the wind direction of the air duct is in the leeward direction relative to the air duct cross section 1, the compression spring 5 and the indicator line 3 are arranged on the right side of the Magnus roller 2 to drive the Magnus roller 2 to rotate clockwise. The above arrangement is mainly for arranging the compression spring 5 and the indicator line 3 in the pressure area, because the indicator line 3 will move out of the air duct under pressure and move into the air duct under tension, and moving out of the air duct is more conducive to the reading of the displacement of the indicator line 3.

[0032] like Figure 2 The wind direction of the air duct is inward from the paper surface, that is, the windward direction relative to the air duct section 1. According to the Kutta-Joukowski theorem, a low wind speed and high pressure area is formed on the right side of the Magnus drum 2, and a high wind speed and low pressure area is formed on the left side of the Magnus drum 2. The force direction is from right to left. At this time, the Magnus drum 2 is pushed to the left to squeeze the compression spring 5, and the indicator line 3 with scale also changes in displacement.

[0033] In this embodiment, the displacement measuring mechanism can also be replaced with a pressure measuring mechanism. Specifically, the pressure measuring mechanism includes a pressure sensor. The ends of the upper connecting block 9 and the lower connecting block 10 away from the Magnus roller 2 are fixed to the inner wall of the closed slide 4. The upper connecting block 9 is rotatably connected to the Magnus roller 2 through a bearing. When the wind direction of the duct is in the windward direction relative to the duct section 1, the pressure sensor is fixed in any of the upper and lower closed slides 4 near the left side of the Magnus roller 2 to drive the Magnus roller 2 to rotate counterclockwise. When the wind direction of the duct is in the leeward direction relative to the duct section 1, the pressure sensor is fixed in any of the upper and lower closed slides 4 near the right side of the Magnus roller 2 to drive the Magnus roller 2 to rotate clockwise. The pressure sensor is electrically connected to a controller. The pressure sensor is provided to measure the air volume of the duct section 1. It is only necessary to ensure that the Magnus roller 2 rotates in place. The upper connecting block 9 and the lower connecting block 10 do not need to slide in the closed slide 4. In order to simply realize the rotation of the Magnus roller 2 and the upper connecting block 9, a slot can be set at the bottom of the upper connecting block 9, and the bearing is fixed in the slot, and the rotation relationship between the two is realized through the bearing. The position setting of the pressure sensor is also based on setting the pressure sensor in the pressure area.

[0034] As an optimization, key materials such as the Magnus roller 2 in this device need to be selected according to the temperature of the medium. Q345B is used for high-temperature air ducts, and Q235 or PVC plastic lightweight materials are used for normal temperature air ducts.

[0035] Embodiment 2

[0036] This embodiment provides a method for measuring velocity deviation of a large cross-section wind duct based on a Magnus device provided with a displacement measuring mechanism, comprising the following steps:

[0037] Step A1, select multiple cross sections at intervals along the length direction of the wind duct, and arrange the Magnus device in each cross section. The multiple cross sections here are multiple array units, and the Magnus device for measuring the velocity deviation of the large cross section wind duct is a device with a displacement measurement mechanism.

[0038] Step A2, according to the wind direction in the air duct, the displacement measuring mechanism is set on the left or right side of the Magnus drum 2, and the Magnus drum 2 is driven to rotate counterclockwise or clockwise according to the wind direction in the air duct. At this time, the Magnus drum 2 is subjected to pressure to the left or right, causing the compression spring 5 to deform, and the indicator line 3 to shift. The displacement value of the indicator line 3 is obtained according to the scale change on the indicator line 3. The displacement value of the indicator line 3 is used to represent the air duct velocity value of the sampling point in the area where the Magnus drum 2 is located, and there is no need to convert the displacement into velocity. It should be understood that the position of the displacement measuring mechanism needs to ensure that it is in the pressure area.

[0039] Step A3, obtain the displacement values ​​of the indicator line 3 of all Magnus rollers 2 in the cross section in the manner described in step A2, and then calculate the average displacement value of the indicator line 3. The average displacement value of the indicator line 3 is also used to represent the average velocity value of the air duct in the cross section. The formula is as follows: in, is the average displacement representing the average speed, V1, V2...Vn are the displacements of the sampling point indicator line 3 representing the air duct speed at the sampling point, and n is the number of sampling points;

[0040] Step A4: Substitute the displacement value of the sampling point indicator line 3 in step A3 and the average displacement value of the indicator line 3 of the cross section into the calculation formula Get the velocity standard deviation, where The average displacement of the indicator line 3 represents the average velocity of the wind duct in this section, V J The displacement of sampling point indicator line 3 represents the air duct velocity at sampling point J, S is the velocity standard deviation, and n is the number of partitions; the calculation formula is Get the relative standard deviation rate, where S is the speed standard deviation, is the average velocity of the air duct in this section; CV is the relative standard deviation rate.

[0041] Embodiment 3

[0042] This embodiment provides a method for measuring velocity deviation of a large cross-section wind duct based on a Magnus device provided with a pressure measuring mechanism, comprising the following steps:

[0043] Step B1, select multiple cross sections at intervals along the length direction of the wind duct, and arrange the Magnus device in each cross section. The multiple cross sections here are multiple array units, and the Magnus device for measuring the velocity deviation of the large cross-section wind duct is a device with a pressure measurement mechanism.

[0044] Step B2, according to the wind direction in the air duct, a pressure sensor is set in the closed slideway 4 on the left or right side of the Magnus roller 2, and the Magnus roller 2 is driven to rotate counterclockwise or clockwise according to the wind direction in the air duct. At this time, the Magnus roller 2 is subjected to pressure to the left or right, and the pressure value, i.e., the pressure value of the Magnus roller 2, is obtained through the pressure sensor, and the pressure sensor converts the force condition of the Magnus roller 2 into an electrical signal in real time and transmits it to the controller. It should be understood that the position of the pressure measuring mechanism needs to ensure that it is in the pressure area.

[0045] Step B3, calculate the air duct velocity value of the sampling point in the area where the Magnus roller 2 is located by the pressure value of the Magnus roller 2. The specific method is: firstly measure the radius and the angular velocity of the Magnus roller 2 and substitute them into the calculation formula Γ=2πr 2w is used to obtain the circulation of the Magnus cylinder 2, where Γ is the circulation, r is the radius of the Magnus cylinder 2, and w is the angular velocity of the Magnus cylinder 2; secondly, the pressure value of the Magnus cylinder 2 and the circulation of the Magnus cylinder 2 are substituted into the calculation formula L=-ρV ∞ The fluid velocity value in the area where the Magnus roller 2 is located is obtained by Γ as the air duct velocity value of the sampling point, where ρ is the fluid density, V is the fluid velocity, Γ is the circulation, and L is the pressure.

[0046] Step B4, obtain the air duct velocity values ​​of all sampling points in the area where the Magnus rollers 2 of the cross section are located in the manner described in step B3, and then calculate the average air duct velocity value of the cross section. Formula reference: in, is the average velocity, V1, V2...Vn are the air duct velocities at the sampling points, and n is the number of sampling points.

[0047] Step B5, substituting the average duct velocity value obtained in step B4 into the calculation formula Q=VA to obtain the air volume of the duct section 1, wherein Q is the air volume, V is the average duct velocity, and A is the duct cross-sectional area.

[0048] The specific embodiments of the present invention are described in detail above with reference to the drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A Magnus device for measuring velocity deviation and air volume in a large cross-section air duct, the device being arranged horizontally and characterized by: The device comprises a plurality of hollow Magnus rollers (2) arranged in an array along a cross section of an air duct (1); the plurality of Magnus rollers (2) rotate in a direction perpendicular to the air duct; closed slideways (4) are respectively arranged above and below the Magnus rollers (2) in the same horizontal direction; an upper connecting block (9) and a lower connecting block (10) are respectively connected to the top and bottom of each Magnus roller (2); the upper connecting block (9) and the lower connecting block (10) are respectively arranged in the upper and lower closed slideways (4); the lower connecting block (10) and the upper and lower closed slideways (4) are respectively arranged in the upper and lower closed slideways (4); the upper and lower connecting blocks (10 ... A motor (7) is arranged in the connection block (10), and an output shaft of the motor (7) is rotationally connected to the Magnus roller (2) through a roller connecting rod (8), and the roller connecting rod (8) is arranged in the Magnus roller (2), and one end of the roller connecting rod (8) away from the Magnus roller (2) extends out of the Magnus roller (2) and is connected to the output shaft of the motor (7), and a displacement measuring mechanism or a pressure measuring mechanism is arranged in a closed slideway (4) on one side of the Magnus roller (2).

2. The Magnus device for measuring velocity deviation and air volume in a large cross-section air duct according to claim 1, characterized in that: The displacement measuring mechanism comprises a compression spring (5) and an indicator line (3); the upper connecting block (9) is fixedly connected to the Magnus roller (2); the upper connecting block (9) and the lower connecting block (10) are respectively slidably connected to the upper and lower closed slideways (4); two compression springs (5) are arranged on the same side; one end of the two compression springs (5) is respectively connected to the upper connecting block (9) and the lower connecting block (10); the other end of the two compression springs (5) is fixed to the inner wall of the closed slideway (4); the indicator line (3) is arranged on the same side as the compression spring (5); one end of the indicator line (3) is fixed to the upper connecting block (9) or the lower connecting block (10); the other end of the indicator line (3) extends out of the air duct; and a scale is provided on the indicator line (3).

3. The Magnus device for measuring velocity deviation and air volume in a large cross-section air duct according to claim 2, characterized in that: When the wind direction of the air duct is in the windward direction relative to the air duct cross section (1), the compression spring (5) and the indicator line (3) are arranged on the left side of the Magnus roller (2) to drive the Magnus roller (2) to rotate counterclockwise; when the wind direction of the air duct is in the leeward direction relative to the air duct cross section (1), the compression spring (5) and the indicator line (3) are arranged on the right side of the Magnus roller (2) to drive the Magnus roller (2) to rotate clockwise.

4. The Magnus device for measuring velocity deviation and air volume in a large cross-section air duct according to claim 1, characterized in that: The pressure measuring mechanism comprises a pressure sensor, the ends of the upper connecting block (9) and the lower connecting block (10) away from the Magnus roller (2) are fixed to the inner wall of the closed slideway (4), and the upper connecting block (9) is rotatably connected to the Magnus roller (2) via a bearing; When the wind direction of the air duct is in the windward direction relative to the air duct cross section (1), the pressure sensor is fixed in any one of the upper and lower closed slideways (4) close to the left side of the Magnus roller (2), driving the Magnus roller (2) to rotate counterclockwise; when the wind direction of the air duct is in the leeward direction relative to the air duct cross section (1), the pressure sensor is fixed in any one of the upper and lower closed slideways (4) close to the right side of the Magnus roller (2), driving the Magnus roller (2) to rotate clockwise; the pressure sensor is electrically connected to a controller.

5. The Magnus device for measuring velocity deviation and air volume in a large cross-section air duct according to claim 1, characterized in that: The motor (7) is connected to a power source (6), and the device is arranged at 3-5 times the equivalent diameter upstream or downstream of the elbow.

6. The Magnus device for measuring velocity deviation and air volume in a large cross-section air duct according to claim 1, characterized in that: When the air duct is a high-temperature air duct, the device is made of Q345B, and when the air duct is a normal-temperature air duct, the device is made of Q235 or PVC plastic lightweight material.

7. The method for measuring velocity deviation of a large cross-section wind duct using a Magnus device according to claim 3, characterized in that: The steps include: Step A1, selecting a plurality of cross sections along the length direction of the air duct, and arranging the Magnus device in each cross section; Step A2, according to the wind direction in the air duct, a displacement measuring mechanism is arranged on the left or right side of the Magnus roller (2), and at the same time, the Magnus roller (2) is driven to rotate counterclockwise or clockwise according to the wind direction in the air duct. At this time, the Magnus roller (2) is subjected to pressure to the left or right, causing the compression spring (5) to deform, and at the same time, the indicator line (3) is displaced. The displacement value of the indicator line (3) is obtained according to the scale change on the indicator line (3), and the air duct velocity value of the sampling point in the area where the Magnus roller (2) is located is represented by the displacement value of the indicator line (3); Step A3, obtaining the displacement values ​​of the indicator line (3) of all Magnus rollers (2) in the cross section in the manner described in step A2, and then calculating the average displacement value of the indicator line (3), and also using the average displacement value of the indicator line (3) to represent the average velocity value of the air duct in the cross section; Step A4, substitute the displacement value of the sampling point indicator line (3) in step A3 and the average displacement value of the indicator line (3) of the cross section into the calculation formula Get the velocity standard deviation, where The average displacement of the indicator line (3) represents the average velocity of the wind tunnel in this section, V J The displacement of the sampling point indicator line (3) represents the velocity of the sampling point J, S is the velocity standard deviation, and n is the number of partitions; the calculation formula is Get the relative standard deviation rate, where S is the speed standard deviation, is the average velocity of the air duct in this section; CV is the relative standard deviation rate.

8. The method for measuring the air volume of a large cross-section air duct using a Magnus device according to claim 4, characterized in that: The steps include: Step B1, selecting a plurality of cross sections along the length direction of the air duct, and arranging the Magnus device in each cross section; Step B2, according to the wind direction in the air duct, a pressure sensor is arranged in the closed slideway (4) on the left or right side of the Magnus roller (2), and at the same time, the Magnus roller (2) is driven to rotate counterclockwise or clockwise according to the wind direction in the air duct. At this time, the Magnus roller (2) is subjected to pressure to the left or right, and a pressure value, i.e., the pressure value of the Magnus roller (2), is obtained through the pressure sensor, and the pressure sensor converts the force condition of the Magnus roller (2) into an electrical signal in real time and transmits it to the controller; Step B3, calculating the air duct velocity value of the sampling point in the area where the Magnus roller (2) is located through the pressure value of the Magnus roller (2); Step B4, obtaining the air duct velocity values ​​of the sampling points in the area where all the Magnus rollers (2) of the cross section are located in the manner described in step B3, and then calculating the average air duct velocity value of the cross section; Step B5, substituting the average duct velocity value obtained in step B4 into the calculation formula Q=VA to obtain the air volume of the duct section (1), wherein Q is the air volume, V is the average duct velocity, and A is the area of ​​the duct section (1).

9. The method for measuring a large cross-section air duct according to claim 8, characterized in that: In step B3, the method for calculating the fluid velocity value in the area where the Magnus roller (2) is located by using the pressure value of the Magnus roller (2) is as follows: firstly, the radius and the angular velocity of the Magnus roller (2) are measured and substituted into the calculation formula Γ=2πr 2 w is used to obtain the circulation of the Magnus roller (2), where Γ is the circulation, r is the radius of the Magnus roller (2), and w is the angular velocity of the Magnus roller (2). Secondly, the pressure value of the Magnus roller (2) and the circulation of the Magnus roller (2) are substituted into the calculation formula L=-ρV ∞ The fluid velocity value in the area where the Magnus roller (2) is located is obtained as the air duct velocity value of the sampling point, where ρ is the fluid density, V is the fluid velocity, Γ is the circulation, and L is the pressure.

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