A high-precision sonic nozzle flow measuring device

Abstract

The application discloses a high-precision sonic nozzle flow measuring device, which comprises an air inlet stagnation tank and an air outlet pressure stabilizing tank, a sonic nozzle assembly is installed at the connecting position of the air inlet stagnation tank and the air outlet pressure stabilizing tank, the sonic nozzle assembly adopts multi-grade nozzle arbitrary combination, and a rectification damping net assembly is installed in the air inlet stagnation tank and the air outlet pressure stabilizing tank. The multi-layer staggered net body can attenuate airflow vortex, turbulence and pressure pulsation layer by layer, can homogenize the turbulent airflow into stable laminar flow, and can greatly reduce the measurement interference caused by flow field fluctuation. 2048 kinds of on-off combinations of 11 groups of nozzles are provided, 2047 kinds of effective flow cross sections are provided except for the invalid state of all blockages, single or multiple nozzles can be freely matched according to the size of the flow to be measured to work cooperatively, and the complete test interval from small flow to large flow is completely covered. The flow specification can be switched by only replacing the blocking plate during the test process, the nozzle body does not need to be disassembled, and the defects of the traditional device, such as narrow range and frequent replacement of test pieces, are solved.

Description

Technical Field

[0001] This invention relates to the field of nozzle flow measurement technology, specifically a high-precision sonic nozzle flow measurement device using an intelligent pressure sensor. Background Technology

[0002] Aerospace flow measurement requires extremely high accuracy and repeatability, and sonic nozzles are widely used in this field. Relying on the stable and reproducible flow characteristics under critical flow conditions, sonic nozzles are a core standard device for gas flow calibration.

[0003] Existing sonic nozzle flow measurement devices generally suffer from limitations such as narrow range coverage and low switching efficiency. When dealing with test specimens of different flow specifications, they require frequent disassembly and replacement, which is cumbersome and the repeated wear of the sealing surface can easily introduce leakage errors. At the same time, some devices have insufficient flow field rectification design, resulting in large fluctuations in stagnation parameters and low measurement accuracy. Moreover, most of them are fixed structures, which cannot flexibly adapt to multi-station testing scenarios and cannot meet the diverse testing needs of laboratories. Summary of the Invention

[0004] The purpose of this invention is to provide a high-precision sonic nozzle flow measurement device to solve the problems in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-precision sonic nozzle flow measurement device, comprising an inlet stagnation tank and an exhaust pressure stabilizing tank, wherein a sonic nozzle assembly is installed at the connection between the inlet stagnation tank and the exhaust pressure stabilizing tank, and the sonic nozzle assembly adopts an arbitrary combination of multiple nozzles; a rectifier damping mesh assembly is installed in both the inlet stagnation tank and the exhaust pressure stabilizing tank.

[0006] Preferably, the rectifier damping mesh assembly includes a bracket, a gasket, and a rectifier damping mesh. At least three rectifier damping meshes are provided, with a gasket between adjacent rectifier damping meshes. The rectifier damping meshes are fixed on the bracket, which is fixed inside the tank. The mesh openings of adjacent rectifier damping meshes are staggered.

[0007] Preferably, the sonic nozzle assembly consists of multiple sonic nozzles, and a nozzle exhaust plug is detachably installed at one end of each sonic nozzle. The nozzle exhaust plug is a solid circular plate or an annular plate, and the choice of a solid circular plate or an annular plate is made according to the needs of gas flow testing.

[0008] Preferably, a total of eleven sonic nozzles are provided, and the orifice diameters of the multiple sonic nozzles increase sequentially; therefore, the sonic nozzle assembly is arranged as follows: N 总 =2 11 =2048; The effective flow combination mode for the sonic nozzle assembly with media flow is: N 流通 =2 11 -1 = 2047.

[0009] Preferably, the sonic nozzle includes a sleeve, a first sealing ring, a second sealing ring, a sealing gasket, and a nozzle body. The sleeve is mounted on the base plate of the sonic nozzle assembly. The first sealing ring is installed between the sleeve and the base plate. The nozzle body is installed inside the sleeve. The second sealing ring is installed between the nozzle body and the sleeve. The nozzle body and the sleeve are pressed together by a nozzle exhaust plug plate, and a sealing gasket is provided between the nozzle exhaust plug plate and the nozzle body.

[0010] Preferably, the nozzle body is provided with an arc-shaped contraction section, an arc-shaped flare section and a straight flare section at the nozzle orifice, and the arc-shaped contraction section, the arc-shaped flare section and the straight flare section are arranged sequentially from the air inlet end to the air outlet end.

[0011] Preferably, both the intake stagnation tank and the exhaust pressure stabilizing tank are equipped with a pressure measuring connector and a temperature measuring connector. The pressure measuring connector is connected to a pressure gauge with an intelligent pressure sensor through a pressure measuring tube, and the temperature measuring connector is connected to a temperature measuring thermocouple through a temperature measuring cable.

[0012] Preferably, it also includes a base, and both the intake stagnation tank and the exhaust pressure stabilizing tank can be detachably installed on the base, and the bottom of the base is equipped with casters.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. Both the inlet stagnation tank and the exhaust pressure stabilizing tank are equipped with a flow-rectifying damping mesh assembly. The assembly consists of a bracket, gaskets, and three layers of flow-rectifying damping mesh, with adjacent meshes arranged in an alternating pattern. The multi-layered, staggered mesh can gradually attenuate airflow eddies, turbulence, and pressure pulsations, homogenizing turbulent airflow into a stable laminar flow, significantly reducing measurement interference caused by flow field fluctuations. At the same time, the large-volume tank buffers the airflow, and in conjunction with the pressure measuring connector, pressure measuring tube, pressure gauge with intelligent pressure sensor, temperature measuring connector, temperature measuring cable, and precision temperature measuring thermocouple, it can collect stable stagnation temperature and pressure parameters in real time. The upstream and downstream dual pressure stabilization and rectification structures work together to weaken fluctuations in operating parameters, reducing flow calculation errors from the source and achieving high-precision gas flow measurement.

[0014] 2. The sonic nozzle assembly integrates 11 sonic nozzles with gradually increasing orifice diameters. Each nozzle is paired with an independent, detachable nozzle exhaust plug. Solid plugs seal the nozzle, while annular plugs allow the nozzle to pass through. The 11 nozzle groups offer 2048 on / off combinations. Excluding the ineffective state of complete blockage, this provides 2047 effective flow cross-sections. Single or multiple nozzles can be freely combined to work in tandem, depending on the flow rate being measured, fully covering the entire testing range from low to high flow rates. During testing, only the plug needs to be replaced to switch flow specifications; there is no need to disassemble the nozzle body, overcoming the shortcomings of traditional devices such as narrow measurement range and frequent specimen changes.

[0015] 3. A single sonic nozzle employs a multi-seal structure consisting of a sleeve, a first sealing ring, a second sealing ring, and a sealing gasket: the sleeve and base plate are sealed by the first sealing ring, a second sealing ring is added between the nozzle body and the sleeve, and the nozzle exhaust plug plate presses against the end face sealing gasket to achieve channel opening and closing. When switching flow levels using the plug plate, there is no need to disassemble the sleeve and nozzle body, avoiding the problems of sealing surface wear and sealing failure caused by repeated nozzle disassembly and assembly in traditional devices. This effectively reduces system measurement deviations introduced by leakage and improves measurement repeatability.

[0016] 4. The nozzle body is sequentially configured with an arc-shaped contraction section, an arc-shaped flare section, and a straight flare section along the airflow direction. The arc-shaped contraction section gently accelerates the airflow, which can smoothly establish the throat-level sonic critical flow; the rear arc-shaped and straight flare structures can stabilize the downstream airflow, reduce the impact of the nozzle outlet airflow, ensure the stability of the upstream and downstream pressure ratio of the nozzle, and prevent the occurrence of critical flow instability. This ensures that the theoretical basis of flow calculation remains valid and further improves the stability of the measurement results.

[0017] 5. Both the inlet stagnation tank and the exhaust pressure stabilizing tank are equipped with an independent pressure and temperature measurement unit, which can simultaneously read the upstream stagnation temperature and pressure and the downstream back pressure temperature and pressure. Operators can calculate the upstream and downstream pressure ratio of the nozzle in real time, intuitively determine whether the device maintains a critical flow state, and adjust the inlet parameters in a timely manner if the operating conditions do not meet the measurement requirements, avoiding invalid tests under non-critical flow conditions and improving test efficiency and data validity.

[0018] 6. This device is equipped with dedicated pressure and temperature sensing and acquisition components, which are built-in metering sensors. Both the inlet stagnation tank and the exhaust pressure stabilizing tank have pre-installed pressure and temperature measuring connectors on their walls. The pressure measuring connector connects to a pressure gauge with an intelligent pressure sensor via a pressure measuring tube, which collects the static pressure value of the gas inside the tank in real time. The temperature measuring connector connects to a precision thermocouple via a temperature measuring cable, which acts as a temperature sensor, continuously collecting the stagnation temperature of the gas inside the tank. These two types of sensors are respectively arranged in the upstream and downstream tanks, allowing simultaneous acquisition of upstream stagnation parameters and downstream back pressure parameters. The sensors output operating condition values ​​in real time, providing continuous and intuitive basic metering data for determining the critical flow state and performing flow rate calculations. These are the core sensing components for achieving high-precision flow rate measurement. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the present invention; Figure 3This is a schematic diagram of the rectifier damping mesh assembly of the present invention; Figure 4 This is a schematic diagram of the nozzle exhaust plug plate of the present invention; Figure 5 This is a cross-sectional view of the nozzle exhaust plug plate of the present invention; Figure 6 This is a schematic diagram of the sonic nozzle and nozzle exhaust plug of the present invention; Figure 7 This is the present invention. Figure 6 A sectional view; Figure 8 This is a schematic diagram of the sonic nozzle and nozzle exhaust plug of the present invention.

[0020] In the diagram: 1. Inlet stagnation tank; 2. Exhaust pressure stabilizing tank; 3. Pressure testing connector; 4. Pressure testing tube; 5. Temperature testing connector; 6. Temperature testing cable; 7. Pressure gauge with intelligent pressure sensor; 8. Temperature measuring thermocouple; 9. Base; 10. Casters; 11. Rectifying damping mesh assembly; 12. Sonic nozzle assembly; 13. Sonic nozzle; 14. Nozzle exhaust plug; 111. Bracket; 112. Gasket; 113. Rectifying damping mesh; 131. Sleeve; 132. First sealing ring; 133. Second sealing ring; 134. Sealing gasket; 135. Nozzle body; 1351. Arc-shaped contraction section; 1352. Arc-shaped flare section; 1353. Straight flare section. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0022] Please see Figure 1-8In this embodiment of the invention, a high-precision sonic nozzle flow measurement device includes an inlet stagnation tank 1 and an exhaust pressure stabilizing tank 2. A sonic nozzle assembly 12 is installed at the connection between the inlet stagnation tank 1 and the exhaust pressure stabilizing tank 2. The sonic nozzle assembly 12 adopts an arbitrary combination of multi-stage nozzles. A rectifier damping mesh assembly 11 is installed inside both the inlet stagnation tank 1 and the exhaust pressure stabilizing tank 2. A pressure measuring connector 3 and a temperature measuring connector 5 are installed in both the inlet stagnation tank 1 and the exhaust pressure stabilizing tank 2. The pressure measuring connector 3 is connected to a pressure gauge 7 with an intelligent pressure sensor through a pressure measuring tube 4. The temperature measuring connector 5 is connected to a temperature measuring thermocouple 8 through a temperature measuring cable 6. Both the inlet stagnation tank 1 and the exhaust pressure stabilizing tank 2 are detachably mounted on a base 9. A caster wheel 10 is installed at the bottom of the base 9. This device is equipped with a dedicated pressure and temperature sensing and acquisition component, which is a built-in metering sensor component. Both the inlet stagnation tank 1 and the exhaust pressure stabilizing tank 2 have pre-installed pressure and temperature measuring connectors on their walls. The pressure measuring connectors are connected to a pressure gauge equipped with an intelligent pressure sensor via a pressure measuring tube. The pressure gauge with the intelligent pressure sensor acts as a pressure sensor, collecting the static pressure value of the gas inside the tank in real time. The temperature measuring connectors are connected to a precision thermocouple via a temperature measuring cable. The precision thermocouple acts as a temperature sensor, continuously collecting the stagnation temperature of the gas inside the tank. The two types of sensors are respectively arranged in the upstream and downstream tanks, which can simultaneously acquire the upstream stagnation parameters and the downstream back pressure parameters. The sensors output operating condition values ​​in real time, providing continuous and intuitive basic metering data for judging the critical flow state and carrying out flow calculations. They are the core sensing components for achieving high-precision flow measurement.

[0023] The rectifying damping mesh assembly 11 includes a support 111, a gasket 112, and a rectifying damping mesh 113. At least three rectifying damping meshes 113 are provided, with a gasket 112 placed between adjacent rectifying damping meshes 113. The rectifying damping meshes 113 are fixed to the support 111, which is fixed inside the tank. The mesh openings of adjacent rectifying damping meshes 113 are staggered. The rectifying damping mesh assembly 11 is assembled from the support 111, the separating gaskets 112, and three layers of rectifying damping meshes 113. With the staggered mesh openings of adjacent rectifying damping meshes 113, when turbulent airflow passes through the multi-layered mesh, eddies, turbulence, and airflow pulsations are gradually attenuated and eliminated, homogenizing the airflow into a stable and uniform laminar flow, thus avoiding measurement deviations caused by flow field distortion.

[0024] The sonic nozzle assembly 12 consists of multiple sonic nozzles 13. One end of each sonic nozzle 13 is detachably fitted with a nozzle exhaust plug 14. The nozzle exhaust plug 14 is either a solid circular plate or an annular plate. Depending on the gas flow test requirements, either a solid circular plate or an annular plate can be selected. A solid nozzle exhaust plug 14 can seal the corresponding nozzle by pressing it against the sealing gasket 134. An annular nozzle exhaust plug 14 can retain the airflow channel to keep the nozzle open.

[0025] There are eleven sonic nozzles 13 in total, and the orifice diameters of the multiple sonic nozzles 13 increase sequentially; therefore, the sonic nozzle assembly 12 is arranged as follows: N 总 =2 11 =2048; The effective flow combination mode for the sonic nozzle assembly 12 with medium flow is: N 流通 =2 11 -1=2047. The 11 sets of sonic nozzles 13 have a total of 2048 on / off combinations. After eliminating all invalid working conditions with blockages, there are 2047 effective flow sections, which can be freely matched to adapt to the full range of flow tests without disassembling the nozzle body. Each sonic nozzle 13 adopts a triple sealing structure consisting of a sleeve 131, a first sealing ring 132, a second sealing ring 133, and an end face sealing gasket 134. The nozzle exhaust plug plate 14 directly presses the seal to achieve on / off switching, without the need for repeated disassembly and assembly of the sealing surface, avoiding leakage errors caused by seal wear. Inside the nozzle body 135, an arc-shaped contraction section 1351, an arc-shaped flare section 1352, and a straight flare section 1353 are arranged sequentially along the airflow direction. The gas flows through the contraction section and is continuously accelerated. When the pressure ratio between the upstream and downstream of the nozzle reaches the critical flow judgment condition, the airflow at the nozzle throat reaches the speed of sound. Under the critical flow condition, the change in downstream back pressure will not interfere with the sonic state of the throat. The gas flow rate is determined only by the upstream stagnation pressure, stagnation temperature, and the nozzle calibration outflow coefficient.

[0026] The sonic nozzle 13 includes a sleeve 131, a first sealing ring 132, a second sealing ring 133, a sealing gasket 134, and a nozzle body 135. The sleeve 131 is mounted on the base plate of the sonic nozzle assembly 12. The first sealing ring 132 is installed between the sleeve 131 and the base plate. The nozzle body 135 is installed inside the sleeve 131. The second sealing ring 133 is installed between the nozzle body 135 and the sleeve 131. The nozzle body 135 and the sleeve 131 are pressed together by a nozzle exhaust plug 14, and a sealing gasket 134 is provided between the nozzle exhaust plug 14 and the nozzle body 135. The nozzle body 135 has an arc-shaped contraction section 1351, an arc-shaped flare section 1352, and a straight flare section 1353 at the nozzle orifice. The arc-shaped contraction section 1351, the arc-shaped flare section 1352, and the straight flare section 1353 are arranged sequentially from the air inlet end to the air outlet end.

[0027] The working principle of this invention is as follows: gas is first introduced into the inlet stagnation tank 1 to complete the flow field pretreatment and stagnation parameter acquisition. This step is achieved by relying on the inlet stagnation tank 1, the three-layer staggered rectifier damping mesh assembly 11, the pressure measuring connector 3, the temperature measuring connector 5, and the matching pressure gauge 7 with intelligent pressure sensor, the temperature measuring thermocouple 8, the pressure measuring tube 4, and the temperature measuring cable 6. The rectifier damping mesh assembly 11 is assembled from a bracket 111, a separator 112, and a three-layer rectifier damping mesh 113. The meshes of adjacent rectifier damping meshes 113 are arranged in an alternating pattern. When the turbulent intake airflow passes through the multi-layer mesh, the eddies, turbulence, and airflow pulsations are gradually attenuated and eliminated, and the airflow is homogenized into a stable and uniform laminar flow, avoiding measurement deviations caused by flow field distortion. The large-volume intake stagnation tank 1 can buffer the airflow, making the gas velocity inside the tank approach zero, forming a standard stagnation condition. The pressure measuring connector 3 and temperature measuring connector 5 on the side wall of the tank are connected to a pressure gauge 7 with an intelligent pressure sensor and a temperature measuring thermocouple 8 through a pressure measuring tube 4 and a temperature measuring cable 6, respectively, to collect the stable upstream stagnation pressure and stagnation temperature inside the tank in real time, providing core basic parameters for flow calculation.

[0028] After being rectified and stabilized, the airflow enters the sonic nozzle assembly 12. The critical flow state is established through the switchable nozzle structure. This process relies on the 11-level gradient aperture sonic nozzle 13, the detachable nozzle exhaust plug 14, the sleeve 131, the first sealing ring 132, the second sealing ring 133, the sealing gasket 134, and the three-section nozzle body 135 to achieve range adaptation and critical flow generation. The device consists of 11 independent sonic nozzles 13 with progressively larger orifice diameters. Each sonic nozzle 13 is equipped with a replaceable nozzle exhaust plug 14 at its outlet. A solid nozzle exhaust plug 14 can seal the corresponding nozzle by pressing it against a sealing gasket 134, while an annular nozzle exhaust plug 14 can maintain the airflow channel, allowing the nozzle to remain open. The 11 sets of sonic nozzles 13 provide 2048 possible on / off combinations. After eliminating all invalid conditions caused by blockage, there are 2047 effective flow cross sections, which can be freely combined to adapt to flow rate testing across the entire range without disassembling the nozzle body. Each sonic nozzle 13 uses a sleeve 131, a first sealing ring 132, and a second sealing ring 13. 3. The end face sealing gasket 134 forms a triple sealing structure. The nozzle exhaust plug plate 14 directly presses and seals to achieve on / off switching, eliminating the need for repeated disassembly and assembly of the sealing surface and avoiding leakage errors caused by seal wear. Inside the nozzle body 135, an arc-shaped constriction section 1351, an arc-shaped flare section 1352, and a straight flare section 1353 are arranged sequentially along the airflow direction. The gas flows through the constriction section and continuously accelerates. When the pressure ratio between the upstream and downstream of the nozzle reaches the critical flow judgment condition, the airflow at the nozzle throat reaches the speed of sound. Under the critical flow condition, the change in downstream back pressure will not interfere with the speed of sound at the throat. The gas flow rate is determined only by the upstream stagnation pressure, stagnation temperature, and the nozzle calibration outflow coefficient.

[0029] The gas flowing from the sonic nozzle 13 enters the exhaust pressure stabilizing tank 2 to complete the downstream back pressure stabilization and critical flow state verification. This part of the structure is consistent with the inlet stagnation tank 1, and is also equipped with a three-layer staggered rectification damping mesh assembly 11 and independent pressure measuring connector 3, temperature measuring connector 5, pressure gauge 7 with intelligent pressure sensor, and temperature measuring thermocouple 8 data acquisition unit. After the high-speed airflow discharged from the nozzle enters the exhaust pressure stabilizing tank 2, the internal rectification damping mesh assembly 11 further attenuates the airflow impact and pressure pulsation, stabilizing the downstream back pressure in the tank. The pressure gauge 7 with intelligent pressure sensor and temperature measuring thermocouple 8 equipped with the tank body collect the downstream pressure and temperature in real time. The operator can calculate the pressure ratio based on the upstream and downstream temperature and pressure values ​​to determine whether the nozzle is stably maintaining the critical flow. If the critical flow condition is not met, the inlet pressure is adjusted until the effective metering condition is reached, ensuring that the collected upstream stagnation parameters have calculation validity.

[0030] The entire equipment is equipped with a detachable profile base 9 and locking casters 10, providing stable operating conditions for multi-station testing. The inlet stagnation tank 1 and the exhaust pressure stabilizing tank 2 can be detached and fixed to the profile base 9. The four corners of the bottom of the base 9 are equipped with casters 10 with locking function. Before testing, the whole machine can be pushed to any test station, and the casters 10 can be locked to fix the equipment, preventing the device from shifting or the pipeline from being deformed due to airflow impact. At the same time, the equipment can be quickly transferred between different stations in the laboratory. The transfer process does not require disassembly of the tank, pipeline and sonic nozzle assembly 12, which can maintain the original sealing structure and flow field state and eliminate the system measurement error introduced by disassembly and assembly operations.

[0031] After all structures work together to achieve stable operating conditions and acquire parameters, accurate flow rate calculation can be completed. The rectifier damping mesh assembly 11 eliminates airflow disturbances and obtains stable, high-precision upstream stagnation pressure and stagnation temperature. The corresponding sonic nozzle 13 is selected by combining the nozzle exhaust plug plate 14, and the nozzle is confirmed to be stable at the critical flow by the temperature and pressure acquisition element of the exhaust pressure stabilizing tank 2. The discharge coefficient of each sonic nozzle 13 is retrieved from the factory calibration, substituted into the standard flow rate calculation formula for the critical flow of the sonic nozzle, and combined with the acquired stagnation parameters, the high-precision gas flow rate value can be calculated.

[0032] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-precision sonic nozzle flow measurement device, characterized in that: It includes an intake stagnation tank (1) and an exhaust pressure stabilizing tank (2). A sonic nozzle assembly (12) is installed at the connection between the intake stagnation tank (1) and the exhaust pressure stabilizing tank (2). The sonic nozzle assembly (12) adopts a combination of multiple nozzles. A rectifier damping mesh assembly (11) is installed in both the intake stagnation tank (1) and the exhaust pressure stabilizing tank (2). A pressure measuring connector (3) and a temperature measuring connector (5) are installed in both the intake stagnation tank (1) and the exhaust pressure stabilizing tank (2). The pressure measuring connector (3) is connected to a pressure gauge (7) with an intelligent pressure sensor through a pressure measuring tube (4). The temperature measuring connector (5) is connected to a temperature measuring thermocouple (8) through a temperature measuring cable (6).

2. The high-precision sonic nozzle flow measurement device according to claim 1, characterized in that: The rectifier damping mesh assembly (11) includes a bracket (111), a gasket (112), and a rectifier damping mesh (113). At least three rectifier damping meshes (113) are provided. A gasket (112) is provided between adjacent rectifier damping meshes (113). The rectifier damping meshes (113) are fixed on the bracket (111), and the bracket (111) is fixed inside the tank. The mesh openings of adjacent rectifier damping meshes (113) are staggered.

3. The high-precision sonic nozzle flow measurement device according to claim 1, characterized in that: The sonic nozzle assembly (12) consists of multiple sonic nozzles (13). One end of each sonic nozzle (13) is detachably fitted with a nozzle exhaust plug (14). The nozzle exhaust plug (14) is either a solid circular plate or an annular plate. The choice of solid circular plate or an annular plate depends on the gas flow rate test requirements.

4. The high-precision sonic nozzle flow measurement device according to claim 3, characterized in that: There are eleven sonic nozzles (13) in total, and the orifice diameters of the multiple sonic nozzles (13) increase sequentially; therefore, the sonic nozzle assembly (12) is assembled in the following way: N 总 =2 11 =2048; The effective flow combination mode for the sonic nozzle assembly (12) with medium flow is: N 流通 =2 11 -1 = 2047.

5. The high-precision sonic nozzle flow measurement device according to claim 4, characterized in that: The sonic nozzle (13) includes a sleeve (131), a first sealing ring (132), a second sealing ring (133), a sealing gasket (134), and a nozzle body (135). The sleeve (131) is mounted on the base plate of the sonic nozzle assembly (12). The first sealing ring (132) is installed between the sleeve (131) and the base plate. The nozzle body (135) is installed inside the sleeve (131). The second sealing ring (133) is installed between the nozzle body (135) and the sleeve (131). The nozzle body (135) and the sleeve (131) are pressed together by a nozzle exhaust plug (14), and a sealing gasket (134) is provided between the nozzle exhaust plug (14) and the nozzle body (135).

6. The high-precision sonic nozzle flow measurement device according to claim 5, characterized in that: The nozzle body (135) is provided with an arc-shaped contraction section (1351), an arc-shaped flare section (1352), and a straight flare section (1353) at the nozzle orifice. The arc-shaped contraction section (1351), the arc-shaped flare section (1352), and the straight flare section (1353) are arranged sequentially from the air inlet end to the air outlet end.

7. The high-precision sonic nozzle flow measurement device according to claim 1, characterized in that: It also includes a base (9), and the intake stagnation tank (1) and the exhaust pressure stabilizing tank (2) can be detachably installed on the base (9). The bottom of the base (9) is equipped with casters (10).

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