Wide-range high-precision flow blocking cone and its usage method

Abstract

This invention relates to a wide-range, high-precision flow blocking cone, comprising an upstream connector, a flow cylinder, a low-pressure connector, and a blocking cone. The upstream connector is located at one end of the flow cylinder, and the blocking cone is coaxially located at the other end of the flow cylinder via the low-pressure connector. The flow area between the flow cylinder and the blocking cone exhibits a pattern of initial contraction followed by expansion. The side of the blocking cone away from the flow cylinder is connected to a motor via a motor output shaft. The blocking cone and the motor are situated in a low-pressure environment. The invention also provides a method for using the aforementioned wide-range, high-precision flow blocking cone. This method divides flow measurement into two stages: a calibration stage and a usage stage. The calibration stage is conducted in a system with uniform incoming flow and a known flow rate. The usage stage involves directly connecting the device to be measured flow. This method can adjust the back pressure at the inlet outlet and suppress errors caused by upstream flow field distortion, thereby improving the accuracy of flow measurement.

Description

Technical Field

[0001] This invention relates to the field of fluid dynamics technology, specifically to a wide-range, high-precision flow blocking cone and its application method. Background Technology

[0002] Engine airflow is a crucial parameter for evaluating engine performance, and accurately obtaining this parameter is an important aspect of engine bench testing and flight testing. Using an inlet duct measuring rake to obtain engine airflow is one of the commonly used methods both domestically and internationally. The typical inlet airflow measurement method employs a cross-section rake, the principle of which is to measure the total pressure distribution and circumferential static pressure at the outlet cross-section to calculate the total flow rate. However, due to factors such as distortion, the accuracy of flow measurement using a cross-section rake is relatively low. Therefore, there is an urgent need to design a new technical solution to comprehensively address the problems existing in current technologies. Summary of the Invention

[0003] The purpose of this invention is to provide a wide-range, high-precision flow blocking cone and its usage method, which can effectively solve the problem of large flow measurement error in the non-uniform flow field at the air intake outlet.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A wide-range, high-precision flow blocking cone includes an upstream connector, a flow cylinder, a low-pressure connector, and a blocking cone. The upstream connector is located at one end of the flow cylinder, and the blocking cone is coaxially located at the other end of the flow cylinder via the low-pressure connector. The flow area between the flow cylinder and the blocking cone exhibits a contraction-expansion pattern. The side of the blocking cone away from the flow cylinder is connected to a motor via a motor output shaft. The blocking cone and the motor are located in a low-pressure environment.

[0006] The flow cylinder is equipped with a pressure sensor for measuring the static pressure inside the flow cylinder and a temperature sensor for measuring the static temperature inside the flow cylinder. The low-pressure connector is equipped with a pressure sensor for measuring the static pressure of the downstream low-pressure environment. The flow cylinder is connected to the flow equipment through the upstream connector and to the low-pressure environment through the low-pressure connector.

[0007] Furthermore, the wide-range high-precision flow blocking cone also includes a honeycomb element, and the upstream connector is located at one end of the flow cylinder via the honeycomb element.

[0008] Furthermore, the end of the flow cylinder near the plug cone is the tail end, and the tail edge of the tail end is chamfered with a chamfer angle of 45° to 90°.

[0009] Furthermore, the motor is a stepper motor, which is fixed on a motor support, and the flow cylinder is connected to the motor support via a motor connecting rod.

[0010] The present invention also provides a method for using the above-mentioned wide-range high-precision flow blocking cone, including a calibration stage and a usage stage; wherein, the calibration stage includes the following steps:

[0011] A1. Connect the gas source with adjustable flow and known gas supply to the gas collection tank and connect it to the upstream of the wide-range high-precision flow blocking cone through the horn mouth. The downstream of the wide-range high-precision flow blocking cone is drawn through the low-pressure chamber, and no honeycomb rectifier is installed in the flow cylinder during this stage.

[0012] A2. Predetermine the absolute zero position of the blocking cone and preset the cone position;

[0013] A3. For any blockage cone position, given the upstream standard flow rate, monitor the ratio of the total pressure in the gas collecting tank to the pressure in the low-pressure chamber to ensure that the blockage cone is blocked;

[0014] A4. After the pressure stabilizes, collect the pressure in the gas collection tank, the pressure and temperature at the preset measuring point of the flow cylinder, the pressure at the bell mouth, and the pressure in the low-pressure chamber.

[0015] A5. Change the position of the blocking cone and repeat steps A3 and A4;

[0016] A6. Calculate the Mach number at the inlet of the flow cylinder and the Mach number inside the flow cylinder based on the recorded data, and calculate the shrinkage ratio of the plug cone when it is in a fixed cone position based on the Mach number at the inlet of the flow cylinder.

[0017] A7. By using the pressure and temperature at the preset measuring points of the flow cylinder and the upstream standard flow rate, we can fit characteristic curves related to the cone position and aerodynamic cross-sectional area, as well as characteristic curves related to the cone position and Mach number inside the flow cylinder.

[0018] The usage phase includes directly connecting the upstream of the wide-range high-precision flow blocking cone to the flow device to be measured, and suctioning downstream through a low-pressure chamber. During this phase, a honeycomb rectifier is installed inside the flow cylinder. Then, at a fixed cone position, given the pressure and temperature at a preset measuring point, the flow rate at this cone position is calculated by referring to the characteristic curve of the cone position and the aerodynamic cross-sectional area.

[0019] The usage phase specifically includes the following steps:

[0020] C1. The upstream of the wide-range high-precision flow blocking cone is directly connected to the flow device to be measured, and the downstream is drawn through a low-pressure chamber. During this stage, a honeycomb rectifier is installed inside the flow cylinder.

[0021] C2. Adjust the position of the plug cone or the downstream pressure to achieve the required operating conditions upstream, and monitor the pressure and temperature inside the flow cylinder at this time;

[0022] C3. Obtain the upstream total pressure by checking the characteristic curve of the cone position and the Mach number in the flow cylinder, and calculate the pressure drop ratio before and after the cone blockage to ensure the flow obstruction at the cone throttling surface;

[0023] C4. After stabilizing the pressure, record the pressure and temperature data at the preset measuring points, and calculate the flow rate at this cone position by referring to the characteristic curve of the cone position and the aerodynamic cross-sectional area.

[0024] C5. Change the position of the blocking cone and repeat steps C2 to C4 to measure the flow rate under different operating conditions.

[0025] In addition, a flow measurement accuracy verification stage is included before the use stage, which includes the following steps:

[0026] B1. Connect the gas source with adjustable flow and known gas supply to the gas collection tank and connect it to the upstream of the wide-range high-precision flow blocking cone through the horn and distortion simulation tube, and install a honeycomb device for rectification. The downstream of the wide-range high-precision flow blocking cone is evacuated through the low-pressure chamber.

[0027] B2. Set the blocking cone position or downstream pressure, and monitor the pressure and temperature inside the flow cylinder at this time;

[0028] B3. Obtain the upstream total pressure by checking the characteristic curve of the cone position and the Mach number in the flow cylinder, and calculate the pressure drop ratio before and after the blockage cone to ensure the flow obstruction at the throttling surface of the blockage cone;

[0029] B4. After stabilizing the pressure, record the pressure and temperature data at the preset measurement points. Calculate the flow rate at this cone position by referring to the characteristic curve of the cone position and the aerodynamic cross-sectional area. Verify the flow accuracy by comparing the calculated flow rate with the standard flow rate. If the accuracy is within 1%, the flow measurement accuracy verification is successful.

[0030] B5. Change the position of the plug cone and repeat steps B2 to B4 to check the measurement accuracy of the flow rate within the width of the plug cone.

[0031] The aforementioned distortion simulation tube is used to simulate the distorted airflow field and verify the accuracy of flow rate measurement using the flow cone. It is also necessary to ensure that the size of the gas collection tank is much larger than the size of the flow cylinder.

[0032] The wide-range, high-precision flow blocking cone provided in the above technical solution is a flow blocking cone that can both adjust pressure and achieve wide-range, high-precision flow measurement. The blocking cone changes the throttling degree at the outlet of the flow cylinder under the drive of a stepper motor, thereby achieving back pressure adjustment or changing the incoming flow rate. At the same time, the flow rate is calculated by using data such as pressure and temperature measured inside the flow cylinder. Based on the gas dynamics flow rate calculation formula, a wide-range, high-precision flow rate measurement method based on a plug cone throttling is proposed. This method can measure the flow rate in the non-uniform flow field at the inlet outlet and can also change the inlet back pressure by adjusting the plug cone throttling degree. The method consists of two parts: a calibration stage and an application stage. In the calibration stage, the plug cone position, aerodynamic cross-sectional area, and inlet Mach number of the flow cylinder are used as calibration parameters to obtain the aerodynamic cross-sectional area characteristic curve and the inlet Mach number characteristic curve of the plug cone. In the application stage, when the plug cone position is determined, the flow rate is calculated by measuring the pressure and temperature and consulting the aerodynamic cross-sectional area characteristic curve of the plug cone. The calibration stage is carried out in a system with uniform incoming flow and known flow rate, while the application stage connects the device directly to the flow rate measurement device. This method can adjust the inlet outlet back pressure and suppress the error caused by upstream flow field distortion, thereby improving the flow rate measurement accuracy.

[0033] The wide-range, high-precision flow blocking cone of this invention is used to measure the intake flow rate and simulate different back pressures. Its principle is to change the throttling area at the outlet of the flow cylinder by changing the calibrated blocking cone, thereby changing the back pressure and flow rate; at the same time, the flow rate of the system is measured by parameters such as the static pressure and total temperature of the flow cylinder. Attached Figure Description

[0034] Figure 1 A schematic diagram of the structure of the wide-range high-precision flow blocking cone described in this invention;

[0035] Figure 2 This is a flowchart illustrating the usage method of the wide-range, high-precision flow blocking cone of the present invention.

[0036] Figure 3 This is a schematic diagram of the test system for the flow rate blockage cone calibration stage in Example 2;

[0037] Figure 4 Calibration curves for the geometric characteristics of the flow-blocking cone;

[0038] Figure 5 Calibration curve for Mach number inside the flow cone flow tank;

[0039] Figure 6 This is a schematic diagram of the flow rate blockage cone measurement accuracy verification test system in Example 2;

[0040] Figure 7 This is a schematic diagram of the installation of the flow blocking cone during the usage stage of Example 2.

[0041] In the diagram: 1. Upstream connecting flange; 2. Cellular unit; 3. Temperature measuring point; 4. Flow cylinder; 5. Pressure measuring point; 6. Back pressure measuring point; 7. Low-pressure connecting flange; 8. Plug cone; 9. Motor connecting rod; 10. Stepper motor; 11. Motor support; 20. Gas supply source; 30. Gas collection tank; 40. Low-pressure chamber; 50. Bell mouth; 60. Distortion simulation tube; 70. Flow device to be measured. Detailed Implementation

[0042] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention.

[0043] Example 1

[0044] The technical solution adopted in this embodiment is as follows: Figure 1 As shown, a wide-range high-precision flow blocking cone includes an upstream connecting flange 1, a honeycomb unit 2, a flow cylinder 4, a low-pressure connecting flange 7, and a blocking cone 8. The upstream connecting flange 1 is located at one end of the flow cylinder 4 via the honeycomb unit 2. The honeycomb unit 2 is installed at the front end of the flow cylinder 4. The internal connection of the flow cylinder 4 is smooth and seamless. In this embodiment, a honeycomb unit with a length L2 (0.8D) is used (the length and hole spacing of the honeycomb unit are determined by its rectification capability).

[0045] The plugging cone 8 is coaxially mounted on the other end of the flow cylinder 4 via a low-pressure connecting flange 7. The flow area between the flow cylinder 4 and the plugging cone 8 first contracts and then expands. The side of the plugging cone 8 away from the flow cylinder 4 is connected to a stepper motor 10 via a motor output shaft. The stepper motor 10 is fixed on a motor support 11. The flow cylinder 4 and the motor support 11 are connected via a motor connecting rod 9. Specifically, the plugging cone head and the plugging cone base are connected to the stepper motor 10 via the motor connecting rod 9. The two ends of the motor connecting rod 9 are fixed to the flow cylinder 4 and the motor support 11, respectively. The flow cylinder is connected to the flow equipment via an upstream connecting flange 1 and to the low-pressure environment via a low-pressure connecting flange 7. The entire downstream device includes the plugging cone, the motor connecting rod, and the motor support, wherein the motor support is connected to the flow cylinder and placed in the downstream low-pressure environment.

[0046] A pressure sensor for measuring the static pressure inside the flow tube is arranged on the flow tube 4. Since the downstream plug cone affects the flow field inside the flow tube, while the parameters in the flow field are relatively uniform after rectification by the honeycomb filter upstream, the pressure measuring point 5 on the flow tube 4 is positioned upstream, and its distance L3 from the trailing edge of the flow tube is controlled between 1D and 2D. Therefore, in this embodiment, the distance L3 from the pressure measuring point to the trailing edge of the flow tube is 1.5D. In addition, a temperature measuring point 3 is also provided on the flow tube 4. The requirements for the temperature measuring point 3 are relatively few, and it can be arranged according to the actual situation.

[0047] In addition, a pressure sensor for measuring the static pressure of the downstream low-pressure environment is arranged on the low-pressure connection flange. A corresponding back pressure measuring point 6 needs to be arranged on the low-pressure connection flange. The back pressure measuring point 6 needs to be able to accurately measure the pressure of the downstream low-pressure environment. In this embodiment, two back pressure measuring points 6 are arranged on the low-pressure connection flange. In actual experiments, the ratio of the static pressure in the flow cylinder to the downstream pressure is used to determine whether there is blockage.

[0048] The chamfering angle of the flow meter's tail edge can be selected between 45° and 90°, provided the pressure ratio is stable and sufficient. In this embodiment, the chamfering angle of the flow meter's tail edge is 45°. The chamfering transition of the flow meter's tail edge reduces the pressure ratio required for blockage by the plugging cone. Considering factors such as processing cost, installation difficulty, and the impact of flow measurement accuracy, the length of the flow meter should be controlled between 2.5D and 5D. In this embodiment, the length L1 of the flow meter is three times the maximum radius D of the plugging cone.

[0049] Example 2

[0050] The technical solution adopted in this embodiment is as follows: Figure 2 As shown, a method for using a wide-range, high-precision flow blocking cone is described. This method divides flow measurement into two stages: calibration and use. The flow is accurately measured through the blocking cone and the flow cylinder.

[0051] The principle of the calibration stage is as follows:

[0052] Gas dynamic flow measurement formula:

[0053] In the formula:

[0054]

[0055]

[0056] For air, γ = 1.4, R = 287 J / (kg·K), then p * and T * These represent the total pressure and total temperature of the sound velocity cross section of the plug cone, respectively, where A is the area of ​​the sound velocity cross section, and q(Ma 喉道 Let q(Ma) be the flow function. Since Ma = 1 for the sound velocity cross section, then q(Ma) = 1. 喉道 ) = 1.

[0057] Furthermore, since the area of ​​the aerodynamic cross-section cannot be accurately measured, the area of ​​the aerodynamic cross-section is calibrated using other known quantities.

[0058] Treating the flow process as an isentropic process, the total static pressure relationship is as follows:

[0059]

[0060] The flow rate formula can be written as:

[0061]

[0062] In this formula, p1 is the static pressure at the flow meter measuring point, T1 is the total temperature at the measuring point, and Ma... 流量管 This is the Mach number at the flow meter point.

[0063] The Mach number inside the flow meter can be uniquely determined by the flow meter area A1 and the sound velocity cross-sectional area A:

[0064] Ma 流量管 A1=A

[0065] The flow rate calculation formula at this time is:

[0066]

[0067] The left side of the formula at this time Defined as the flow characteristic value Y of the blocked cone, the value of Y can be calibrated in the calibration stage by measuring the static pressure and total temperature at the measuring points under the condition of known flow rate, and the characteristic curve of the blocked cone throttling degree and Y can be made by fitting and other methods.

[0068] Principle of usage phase:

[0069] The theoretical flow rate m can be calculated by obtaining the pressure p2 and total temperature T2* at the measuring point of the flow cylinder. 测量 :

[0070]

[0071] Define flow rate precision:

[0072]

[0073] Calibration phase test:

[0074] like Figure 3 As shown, the upstream of the wide-range high-precision flow blocking cone is connected to the gas supply source 20 with adjustable and known flow rate. The gas supply source 20 is connected to the gas collection tank 30 and drawn into the flow cylinder 4 through the horn mouth 50. The downstream is drawn into the flow cylinder 4 through the low-pressure chamber 40. At this time, the honeycomb device 2 is not installed in the flow cylinder 4 for rectification.

[0075] Among them, the gas supply source 20 has a known flow rate and is continuously adjustable. Its function is to provide a known variable flow rate during the cone calibration stage and the flow accuracy verification stage. The size of the gas collecting tank is much larger than that of the flow cylinder. The function of the gas collecting tank is to reduce the incoming flow velocity and provide total pressure data. The function of the low-pressure chamber is to provide a low-pressure environment for the cone to ensure that the cone is blocked.

[0076] The calibration phase steps are as follows:

[0077] Step 1: Predetermine the absolute zero position of the blocking cone and preset the cone position through simulation or other methods;

[0078] Step 2: For any blockage cone position x, given the upstream standard flow rate, monitor the ratio of the total pressure in the gas collecting tank to the pressure in the low-pressure chamber during the experiment, and ensure that the pressure ratio reaches 2.5 or above to ensure that the blockage cone is blocked.

[0079] Step 3: After the pressure stabilizes, collect the pressure inside the gas collection tank, the pressure at the flare opening, the pressure and temperature at the preset measuring points on the flow meter, and the pressure inside the low-pressure chamber.

[0080] Step 4: Change the position of the blocking cone and conduct a repeatability test.

[0081] Data processing during calibration phase:

[0082] S1. Treat the pressure inside the gas collecting tank as the total incoming pressure, and calculate the Mach number by the ratio of the pressure inside the gas collecting tank to the pressure at the bell mouth, and use it as the Mach number at the inlet of the flow cylinder.

[0083] S2. The Mach number is calculated by the ratio of the pressure inside the gas collecting tank to the pressure at the preset measuring point of the flow cylinder, and is used as the Mach number inside the flow cylinder;

[0084] S3. Calculate the shrinkage ratio of the plug cone at a fixed cone position based on the inlet Mach number. It should be noted that the inlet Mach number of the flow cylinder is in a one-to-one correspondence with the area ratio and the cone position.

[0085] S4. According to the flow measurement principle of the present invention, by using the pressure and temperature at a preset measuring point on the flow cylinder, and the upstream standard flow rate, characteristic curves regarding the cone position and aerodynamic cross-sectional area, as well as characteristic curves regarding the cone position and Mach number inside the flow cylinder, can be fitted. See details. Figure 4 and Figure 5 .

[0086] Flow accuracy verification test:

[0087] Installation diagram of wide-range high-precision flow meter accuracy verification test is shown below. Figure 6 As shown, the upstream of the wide-range high-precision flow blocking cone is connected to an adjustable and known air supply source 20. The air supply source 20 is connected to an air collection tank 30 and drawn into a distortion simulation tube 60 through a bell mouth 50. The distortion simulation tube 60 is directly connected to the flow cylinder 4 and a honeycomb device 2 is installed for rectification. Downstream, it is drawn into a low-pressure chamber 40. The function of the distortion simulation tube 60 is to simulate the distorted airflow field and verify the measurement accuracy of the flow blocking cone.

[0088] The flow accuracy verification test includes the following steps:

[0089] Step 1: Set the position of the plug cone (or downstream pressure) and monitor the pressure inside the flow cylinder at this time;

[0090] The second step is to determine the upstream total pressure by checking the Mach number characteristic curve, and to determine whether the pressure ratio is greater than 2.5 times to ensure that the plug cone is not blocked, and to further ensure the validity of the data.

[0091] Step 3: After stabilizing the voltage, record the pressure and temperature at the preset measuring points;

[0092] Step 4: Change the position of the blocking cone and repeat steps 1 through 3.

[0093] Flow accuracy verification data processing:

[0094] Given the pressure and temperature at a predetermined measuring point at a fixed cone position, the flow rate at this cone position can be calculated by referring to the aerodynamic cross-sectional area cone characteristic curve. The calculated flow rate is then compared with the standard flow rate to verify the flow accuracy. If the accuracy is within 1%, the flow accuracy verification is considered successful.

[0095] Usage phase trial:

[0096] like Figure 7 As shown, the upstream of the wide-range high-precision flow blocking cone is directly connected to the flow measurement device 70, and the connection is guaranteed to be smooth and seamless. Downstream, a low-pressure chamber 40 performs low-pressure suction to ensure that the blocking cone is blocked and forms a sound velocity cross section.

[0097] The usage phase includes the following steps:

[0098] Step 1: Set the blocking cone position (or downstream pressure) to achieve the required operating conditions upstream, and monitor the pressure inside the flow cylinder at this time;

[0099] The second step is to determine the upstream total pressure by checking the Mach number characteristic curve, and then determine whether the ratio of the pressure inside the flow cylinder to the downstream pressure of the plug cone is greater than 2.5 times to ensure that the plug cone is blocked and to further ensure the validity of the data.

[0100] Step 3: After stabilizing the voltage, record the pressure and temperature at the preset measuring points;

[0101] Step 4: Change the position of the blocking cone and repeat steps 1 through 3.

[0102] Data processing during the usage phase:

[0103] Given the pressure and temperature at a predetermined measuring point at a fixed cone position, the flow rate at this cone position can be calculated by referring to the aerodynamic cross-sectional area cone characteristic curve.

[0104] The wide-range, high-precision flow blocking cone usage method of this embodiment is based on the gas dynamics flow calculation formula. Flow measurement is divided into a calibration stage and a usage stage. In the calibration stage, the cone position, aerodynamic cross-sectional area, and inlet Mach number of the flow cylinder are used as calibration parameters to obtain the aerodynamic cross-sectional area characteristic curve and the inlet Mach number characteristic curve of the cone. In the usage stage, when the cone position is determined, the flow rate is calculated by measuring pressure and temperature and consulting the aerodynamic cross-sectional area characteristic curve of the cone. This method changes the throttling area at the outlet of the flow cylinder by using a calibrated cone, thereby changing the inlet back pressure and flow rate. Simultaneously, the system flow rate is measured using parameters such as pressure and temperature of the flow cylinder to accurately measure the inlet flow rate.

[0105] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. For those skilled in the art, after learning the contents described in the present invention, several equivalent changes and substitutions can be made without departing from the principle of the present invention. These equivalent changes and substitutions should also be considered to fall within the protection scope of the present invention.

Claims

1. A method of using a wide-range high-precision flow choke, characterized by: The wide-range high-precision flow choke comprises an upstream connector, a flow cylinder, a low-pressure connector and a choke, the upstream connector is arranged at one end of the flow cylinder, the choke is coaxially arranged at the other end of the flow cylinder through the low-pressure connector, the flow area between the flow cylinder and the choke is in the form of first contraction and then expansion, the side of the choke away from the flow cylinder is connected with a motor through a motor output shaft; the choke and the motor are in a low-pressure environment; a pressure sensor for measuring the static pressure in the flow cylinder and a temperature sensor for measuring the static temperature in the flow cylinder are arranged on the flow cylinder, a pressure sensor for measuring the static pressure in the downstream low-pressure environment is arranged on the low-pressure connector; the flow cylinder is connected with a flow device through the upstream connector and connected with a low-pressure environment through the low-pressure connector; The use method of the wide-range high-precision flow choke comprises a calibration stage and a use stage; wherein the calibration stage comprises the following steps: A1. connecting a gas supply source with adjustable flow and known flow to a gas collection tank and connecting the wide-range high-precision flow choke upstream through a horn, and the wide-range high-precision flow choke downstream is connected to a low-pressure cabin for suction, and no honeycomb rectifier is installed in the flow cylinder in this stage; A2. determining the absolute zero position of the choke in advance and presetting the choke position; A3. for any choke position, given the upstream standard flow, monitoring the ratio of the total pressure in the gas collection tank to the pressure in the low-pressure cabin to ensure the choke jamming; A4. after the pressure is stabilized, collecting the pressure in the gas collection tank, the preset measuring point pressure and temperature of the flow cylinder, the pressure at the horn and the pressure in the low-pressure cabin; A5. changing the choke position and repeating steps A3 and A4; A6. calculating the flow cylinder inlet Mach number and the flow cylinder internal Mach number according to the recorded data, and calculating the contraction ratio of the choke at a fixed position according to the flow cylinder inlet Mach number; A7. fitting the characteristic curves of the position and the aerodynamic cross-sectional area, and the characteristic curves of the position and the Mach number in the flow cylinder according to the pressure and temperature at the preset measuring point of the flow cylinder and the upstream standard flow; The use stage comprises directly connecting the wide-range high-precision flow choke upstream to the flow device to be measured, and the downstream is connected to the low-pressure cabin for suction, and a honeycomb rectifier is installed in the flow cylinder in this stage; then at a certain fixed position, the pressure and temperature of the preset measuring point are known, and the flow at this position is calculated by looking up the characteristic curves of the position and the aerodynamic cross-sectional area.

2. The method of using a wide range high accuracy flow choke of claim 1, wherein: The wide-range high-precision flow choke further comprises a honeycomb, and the upstream connector is arranged at one end of the flow cylinder through the honeycomb.

3. The method of using a wide range high accuracy flow choke of claim 1, wherein: The end of the flow cylinder near the choke is a tail end, the tail edge of the tail end is chamfered, and the chamfer angle is 45°-90°.

4. The method of using a wide range high accuracy flow choke of claim 1, wherein: The motor is a stepping motor, the stepping motor is fixed on a motor support, and the flow cylinder and the motor support are connected through a motor connecting rod.

5. The method of using a wide range high accuracy flow choke of claim 1, wherein, The use stage specifically comprises the following steps: C1. directly connecting the wide-range high-precision flow choke upstream to the flow device to be measured, and the downstream is connected to the low-pressure cabin for suction, and a honeycomb rectifier is installed in the flow cylinder in this stage; C2. adjusting the choke position or the downstream pressure to make the upstream reach the required working condition, and monitoring the pressure and temperature in the flow cylinder at this time; C3. Obtain the upstream total pressure by checking the characteristic curve of the cone position and the Mach number in the flow cylinder, and calculate the pressure drop ratio before and after the choke cone to ensure choked flow on the choke cone throttle surface; C4. After the pressure is stabilized, record the pressure and temperature data of the preset measuring points, and calculate the flow rate at this cone position by checking the characteristic curve of the cone position and the aerodynamic cross-sectional area; C5. Change the cone position of the choke cone and repeat steps C2 to C4 to measure the flow rate under different working conditions.

6. The method of using a wide range high accuracy flow choke of claim 1, wherein, Before the use stage, it also includes a flow measurement accuracy verification stage, which includes the following steps: B1. Connect the gas supply source with adjustable flow and known flow to the gas collection tank, and connect it to the upstream of the wide-range high-precision flow choke cone through the horn mouth and distortion simulation pipe, and install the honeycomb for flow straightening, and the downstream of the wide-range high-precision flow choke cone is sucked through the low-pressure cabin; B2. Set the choke cone position or downstream pressure, and monitor the pressure and temperature in the flow cylinder at this time; B3. Obtain the upstream total pressure by checking the characteristic curve of the cone position and the Mach number in the flow cylinder, and calculate the pressure drop ratio before and after the choke cone to ensure choked flow on the choke cone throttle surface; B4. After the pressure is stabilized, record the pressure and temperature data of the preset measuring points, and calculate the flow rate at this cone position by checking the characteristic curve of the cone position and the aerodynamic cross-sectional area; compare the calculated flow rate with the standard flow rate to verify the flow rate accuracy, and if the accuracy is within 1%, it means that the flow measurement accuracy verification is successful; B5. Change the cone position of the choke cone and repeat steps B2 to B4 to verify the measurement accuracy of the wide-range flow choke cone.

7. The method of using a wide range high accuracy flow choke of claim 6, wherein: The distortion simulation pipe is used to simulate the distorted airflow flow field and verify the measurement accuracy of the flow choke cone.

8. The method of using a wide range high accuracy flow choke of claim 1, wherein: The size of the gas collection tank is larger than the size of the flow cylinder.

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