Gas flow measuring system and method based on axial flow fan current collector structure

Abstract

The invention discloses a gas flow measuring system and method based on an axial flow fan current collector structure. An axial flow fan comprises a gas inlet box, a current collector, an impeller section and a diffuser which are connected in sequence. According to the gas flow measuring system, an anti-blocking multi-point flute-shaped pipe pressure taking device installed in a current collector is connected with an on-site instrument cabinet through a pressure guiding pipeline; the on-site instrument cabinet is provided with a pressure transmitter, an atmospheric pressure gauge, a temperature controller, a power switch, a programmable logic controller, an industrial control touch screen all-in-one machine and a valve. The method comprises the steps that the anti-blocking multi-point flute-shaped pipe pressure tapping device is used for conducting pressure tapping on a measured section in real time; the dynamic pressure and static pressure acquisition and processing of the measured cross section are carried out through an integrated pressure acquisition module of the in-situ instrument cabinet; the flow coefficient of the whole set of flow measuring device is obtained; and the gas flow is calculated and obtained based on a built-in calculation program of the local programmable logic controller and is uploaded in real time. The gas flow in the flue gas and air system of the large coal-fired boiler can be accurately and reliably measured in real time.

Description

Technical Field

[0001] The invention belongs to the technical field of coal-fired power plants, and in particular relates to a gas flow measurement system and method based on an axial flow fan collector structure. Background Art

[0002] Gas flow is one of the key parameters for evaluating the operating status of power station fans. Accurate and reliable measurement and real-time monitoring of gas flow is an important basis for evaluating and regulating the aerodynamic performance of power station fans, and has important engineering application value for evaluating the health status of power station fans. Considering that the smoke and air ducts of large coal-fired units are all large-diameter pipes (the equivalent diameter of the pipe is greater than 2m), and the layout is compact, with many special-shaped parts and few straight pipe sections, it is difficult to meet the measurement conditions of conventional gas flow measurement devices due to the turbulent flow field inside the pipe. Real-time, reliable and accurate measurement of gas flow in smoke and air ducts is still a technical problem that needs to be solved urgently.

[0003] At present, axial flow fans have been widely used in boiler smoke and air systems. In order to improve the operating efficiency of axial flow fans, a collector structure is set in the front section of the axial flow fan impeller. The main function of the collector is to collect and speed up the airflow, so that the airflow before entering the impeller is evenly distributed, thereby ensuring the air intake conditions of the impeller. According to the application statistical analysis of axial flow fans of large domestic thermal power units, power station axial flow fans are equipped with a collector structure with significant common characteristics. The structure is a typical conical cylindrical tapered structure with a length of 0.5~2.5m. The flow field in the collector outlet section is uniform and stable, which provides favorable conditions for the accurate measurement of flue gas or air flow. Summary of the invention

[0004] In order to accurately and reliably measure the gas flow rate in a smoke and air system of a large coal-fired boiler in real time, the present invention proposes a gas flow rate measurement system and method based on an axial flow fan collector structure.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A gas flow measurement system based on an axial flow fan collector structure, the axial flow fan comprises an air intake box, a collector, an impeller section and a diffuser connected in sequence; the gas flow measurement system connects an anti-blocking multi-point flute-shaped pipe pressure-taking device installed in the collector with an on-site instrument cabinet by a pressure-leading pipeline; the on-site instrument cabinet is equipped with a pressure transmitter, an atmospheric pressure gauge, a temperature controller, a power switch, a programmable logic controller, an industrial control touch-screen integrated machine and a valve, wherein the power switch controls the power supply of the entire on-site instrument cabinet, the valve realizes the access and isolation of each pressure-leading pipe, the pressure transmitter, the atmospheric pressure gauge and the temperature controller respectively measure the medium pressure, the ambient atmospheric pressure and the medium temperature, and convert them into 4-20mA signals to summarize them to the programmable logic controller for data calculation and analysis, and finally transmit them to the industrial control touch-screen integrated machine for storage and display.

[0006] A further improvement of the present invention is that the impeller section is composed of an inlet guide vane, a moving blade and an outlet guide vane.

[0007] A further improvement of the present invention is that the collector is a tapered cone structure, and the collector tapers at an angle of β =40°~60°, the distance between the gas flow measurement section and the leading edge of the inlet guide vane l =0.2m~1m, and the velocity section uniformity index at the section c v =0.92~1.

[0008] A further improvement of the present invention is that the anti-blocking multi-point flute-shaped pipe pressure-taking device is a composite flute-shaped pipe structure, and the number of static pressure measuring points of a single pressure-taking pipe is n s =2~4, total number of pressure measurement points n d =2~6; and the number of pressure taking pipes is evenly distributed along the axial direction N =3~6.

[0009] A further improvement of the present invention is that the pressure-leading pipeline is made of 316L stainless steel pipe.

[0010] A further improvement of the present invention is that the data collection of the flow measurement device is realized by a programmable logic controller, and the sampling period is t s =0.5s~1.0s, the number of samples in each sampling cycle m ≥10, and the continuous sampling multi-point averaging method was used for data processing, as follows: The data set obtained by continuous sampling within a certain sampling period is { P i}, i =1,2,..., m , then the measured value after data processing at this moment is: .

[0011] A gas flow measurement method based on an axial flow fan collector structure, the method is based on a gas flow measurement system based on an axial flow fan collector structure, comprising: Adopt anti-blocking multi-point flute-shaped pressure-taking device to take pressure of the measuring section in real time; The dynamic and static pressures of the measurement section are collected and processed through the integrated pressure collection module of the local instrument cabinet, including data filtering and abnormal data elimination; The correction coefficient of the anti-blocking multi-point flute-type tube pressure-taking device is obtained through a standard laboratory platform, and high-precision numerical simulation calculations are carried out to obtain the velocity field coefficient of the flow measurement surface, and then the flow coefficient of the entire flow measurement device is obtained; The gas flow is calculated based on the built-in calculation program of the local programmable logic controller and uploaded in real time.

[0012] A further improvement of the present invention is that a multi-point pressure tube correction coefficient is obtained through a standard laboratory platform, and a high-precision numerical simulation calculation is performed to obtain the velocity field coefficient of the flow measurement surface, and then the flow coefficient of the entire flow measurement device is obtained, as follows: The composite flute tube is calibrated on the fluid flow measurement platform in a standard closed pipeline to obtain the velocity correction factor e ; According to the actual fan structure size, a full three-dimensional flow channel model is established, and numerical calculation analysis is carried out to calculate the working condition data. k ≥3, the fan inlet flow should cover the entire use range. At the same time, according to the measurement section distribution, the static pressure and total pressure values ​​at the measurement point of the measurement section under each calculation condition are extracted, that is, the calculation result data set {( Q v-cal , , , ) j}, j =1,2,..., k ; Based on the numerical simulation results {( Q v-cal , , , ) j}, the velocity field coefficient under each working condition is calculated by the relationship between flow rate and dynamic pressure of the measuring surface g j :

[0013] Based on the calculation result data set {( , , ) j Linear regression fitting is performed to obtain the relationship between the velocity field coefficient of the flow measurement section and the measured value ; Flow coefficient of the entire flow measurement device .

[0014] A further improvement of the present invention is that the speed correction factor e The value range is [0.8~1].

[0015] A further improvement of the present invention is that the flow coefficient of the entire flow measurement device obtained by calibration and digital modeling technology is The actual volume flow rate of the medium is calculated based on the measured parameters Q v : .

[0016] Compared with the prior art, the present invention has at least the following beneficial technical effects: The present invention provides a flow measurement system and method for an axial flow fan collector structure. The system installs an anti-blocking multi-point flute-shaped tube pressure-taking device on the axial flow fan collector to measure the total pressure and static pressure of the flue gas in real time, calibrates the pressure-taking tube based on a standard air volume test bench to obtain a correction coefficient, analyzes the internal flow field of the fan with the help of numerical simulation calculations to obtain a velocity field coefficient of the measuring section, and then obtains an accurate flow coefficient of the flow measurement device. Finally, the flow rate of the flue gas is obtained in real time based on the relationship between the dynamic pressure and the volume flow rate.

[0017] Relying on the typical structure of the axial flow fan collector and the characteristics of the internal flow field distribution, this invention effectively solves the problems of low flow measurement accuracy in large-section pipelines and easy clogging of flow measurement devices under complex working conditions, and provides a solution for achieving high-precision online measurement of flue gas flow.

[0018] The flow measurement system and method are characterized by high efficiency, high precision and strong reliability, and are suitable for monitoring gas flow parameters of the smoke and air system of large coal-fired boilers. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the system of the present invention; Figure 2 It is the principle diagram of the method of the present invention; in, Figure 2 middle, P t It is the total pressure of the medium measured by the flow measurement device, in Pa. P s It is the static pressure of the medium measured by the flow measurement device, in Pa. T is the medium temperature of the measuring section, in °C, P atm is the local atmospheric pressure, in Pa, It is the total pressure of the medium after the built-in program continuously samples multiple samples and averages them, in Pa. It is the static pressure of the medium after the built-in program continuously samples multiple samples and averages them, in Pa. It is the medium temperature of the measuring surface after continuous sampling of multiple samples by the built-in program, in °C. It is the local atmospheric pressure after continuous sampling of multiple samples by the built-in program, in Pa. m is the number of consecutive samples,Q v-cal It is the volume flow rate under a certain calculation condition for the numerical simulation analysis of the axial flow fan to be equipped with a flow measurement device, in m³ / h. k To calculate the number of operating conditions, j is the calculation condition number ( j =1,2,…, k ), e is the speed correction coefficient of the pressure taking device obtained under the standard test platform, g j is the velocity field coefficient of the measurement section obtained under the jth calculation condition, λ is the flow coefficient of the entire flow measurement device after calibration, Q v is the volume flow rate monitored in real time, in m³ / h. r j For the j The density of the medium at the measuring cross section under each calculation condition, in kg / m³, r 0 is the medium density under standard conditions, unit is kg / m³, A is the area of ​​the measuring surface, in m 2 , a and b are the coefficients of the relationship between the velocity field coefficient and the measured value.

[0020] In the attached figure: 1. Air intake box; 2. Collector; 3. Impeller section; 4. Diffuser; 5. Anti-blocking multi-point flute-shaped tube pressure taking device; 6. Pressure-leading pipeline; 7. Local instrument cabinet; 8. Pressure transmitter; 9. Atmospheric pressure gauge; 10. Temperature controller; 11. Power switch; 12. Programmable logic controller; 13. Industrial control touch screen all-in-one machine; 14. Valve. DETAILED DESCRIPTION

[0021] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0024] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0026] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0027] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0028] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0029] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0030] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0031] Example 1 like Figure 1 As shown, the present embodiment provides a gas flow measurement system based on an axial flow fan collector structure, the axial flow fan comprises an air intake box 1, a collector 2, an impeller section 3 and a diffuser 4 connected in sequence; the gas flow measurement system connects an anti-blocking multi-point flute-shaped pipe pressure-taking device 5 installed in the collector 2 with an on-site instrument cabinet 7 by a pressure-leading pipeline 6; the on-site instrument cabinet 7 is provided with a pressure transmitter 8, an atmospheric pressure gauge 9, a temperature controller 10, a power switch 11, a programmable logic controller 12, an industrial control touch screen all-in-one machine 13 and a valve 14, wherein the power switch 11 controls the power supply of the entire on-site instrument cabinet, the valve 14 realizes the access and isolation of each pressure-leading pipe, the pressure transmitter 8, the atmospheric pressure gauge 9 and the temperature controller 10 respectively measure the medium pressure, the ambient atmospheric pressure and the medium temperature, and convert them into 4~20mA signals and summarize them to the programmable logic controller 12 for data calculation and analysis, and finally transmit them to the industrial control touch screen all-in-one machine for storage and display.

[0032] In this embodiment, the impeller section 3 is composed of an inlet guide vane, a moving vane and an outlet guide vane. The collector 2 is a tapered conical cylinder structure, and the collector tapers at an angle of β =40°~60°, the distance between the gas flow measurement section and the leading edge of the inlet guide vane l =0.2m~1m, and the velocity section uniformity index at the section c v =0.92~1.

[0033] In this embodiment, the anti-blocking multi-point flute-shaped pipe pressure-taking device 5 is a composite flute-shaped pipe structure, and the number of static pressure measuring points of a single pressure-taking pipe is n s =2~4, total number of pressure measurement points n d =2~6; and the number of pressure taking pipes is evenly distributed along the axial direction N =3~6.

[0034] In this embodiment, the pressure-leading pipeline 6 is made of 316L stainless steel pipe.

[0035] In this embodiment, the data of the flow measurement device is collected by a programmable logic controller, and the sampling period is t s =0.5s~1.0s, the number of samples in each sampling cycle m ≥10, and the continuous sampling multi-point averaging method was used for data processing, as follows: The data set obtained by continuous sampling within a certain sampling period is { P i}, i =1,2,..., m , then the measured value after data processing at this moment is: .

[0036] Example 2 like Figure 1 and Figure 2 As shown, this embodiment provides a gas flow measurement method based on an axial flow fan collector structure, comprising: Adopt anti-blocking multi-point flute-shaped pressure-taking device to take pressure of the measuring section in real time; The dynamic and static pressures of the measurement section are collected and processed through the integrated pressure collection module of the local instrument cabinet, including data filtering and abnormal data elimination; The correction coefficient of the anti-blocking multi-point flute-type tube pressure-taking device is obtained through a standard laboratory platform, and high-precision numerical simulation calculations are carried out to obtain the velocity field coefficient of the flow measurement surface, and then the flow coefficient of the entire flow measurement device is obtained; The gas flow is calculated based on the built-in calculation program of the local programmable logic controller and uploaded in real time.

[0037] In this embodiment, a multi-point pressure tube correction coefficient is obtained through a standard laboratory platform, and a high-precision numerical simulation calculation is performed to obtain the velocity field coefficient of the flow measurement surface, and then the flow coefficient of the entire flow measurement device is obtained, as follows: 1) Calibrate the composite flute tube on the fluid flow measurement platform in a standard closed pipeline to obtain the velocity correction coefficient e , speed correction factor e The value range of is [0.8~1]; 2) Establish a full three-dimensional flow channel model based on the actual fan structure size, carry out numerical calculation analysis, and calculate the working condition data. k ≥3, the fan inlet flow should cover the entire use range. At the same time, according to the measurement section distribution, the static pressure and total pressure values ​​at the measurement point of the measurement section under each calculation condition are extracted, that is, the calculation result data set {( Q v-cal , , , ) j}, j =1,2,..., k ; 3) Based on numerical simulation results {( Q v-cal , , , ) j}, the velocity field coefficient under each working condition is calculated by the relationship between flow rate and dynamic pressure of the measuring surface g j :

[0038] 4) Based on the calculation result data set {( , , ) j Linear regression fitting is performed to obtain the relationship between the velocity field coefficient of the flow measurement section and the measured value ; 5) Flow coefficient of the entire flow measurement device .

[0039] In this embodiment, the flow coefficient of the entire flow measurement device obtained by calibration and digital simulation technology is The actual volume flow rate of the medium is calculated based on the measured parameters Q v : .

[0040] Example 3 A full three-dimensional flow channel calculation model is established for a 600MW axial flow induced draft fan with adjustable blades in a domestic unit. Four calculation conditions are selected for numerical simulation within the conventional working flow range of 200m³ / s~500m³ / s of the fan to determine the measurement section that meets the velocity uniformity requirements, and the velocity field coefficient at the measurement section of the fan is obtained; three anti-blocking multi-point flute-shaped pressure-taking devices are evenly installed along the circumference of the selected measurement section (the pressure-taking device is calibrated by a standard air volume test bench), and an on-site instrument cabinet is configured. The pressure-taking device and the on-site instrument cabinet are connected by a 316L stainless steel pressure-taking pipe. The programmable logic controller in the on-site instrument cabinet realizes the processing of measurement data and flow calculation, as well as the compressed air purge control to prevent the pipeline and the pressure-taking device from being blocked. Then, the measured flow value is transmitted remotely to the online monitoring system platform of the power station fan through optical fiber, so as to realize real-time monitoring of the flow and monitoring and early warning of the fan operation status. According to the on-site statistical data and on-site acceptance test data for more than one year, the flow measurement system and method of the present invention has a measurement error within 3%, with high precision and high reliability. The implementation of the present invention provides a reliable solution for high-precision real-time measurement of the flow of the smoke and air system.

[0041] Example 4 On a 1000MW thermal power unit in China with adjustable blades, the flue gas flow through the fan body is monitored in real time by using the patented gas flow measurement system and method of the present invention. The online monitoring flow is compared according to DL / T 469-2022 "Field Performance Test of Power Plant Boiler Fans", and the measurement accuracy of the online monitoring flow is verified based on the comparison test values. The comparison test was carried out under unit loads of 1000MW, 750MW and 500MW, and the comparison of the measured flow and flow monitoring values ​​under various working conditions is shown in the following table.

[0042] Table 1 Comparison test results

[0043] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0044] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A gas flow measurement system based on an axial flow fan collector structure, characterized in that: The axial flow fan comprises an air intake box (1), a current collector (2), an impeller section (3) and a diffuser (4) which are connected in sequence; the gas flow measurement system connects an anti-blocking multi-point flute-shaped pipe pressure-taking device (5) installed in the current collector (2) to an on-site instrument cabinet (7) via a pressure-inducing pipeline (6); the on-site instrument cabinet (7) is equipped with a pressure transmitter (8), an atmospheric pressure gauge (9), a temperature controller (10), a power switch (11), a programmable logic controller (12), an industrial control touch-screen integrated machine (13) and a valve (14), wherein the power switch (11) controls the power supply of the entire on-site instrument cabinet, the valve (14) realizes the connection and isolation of each pressure-inducing pipe, the pressure transmitter (8), the atmospheric pressure gauge (9) and the temperature controller (10) respectively measure the medium pressure, the ambient atmospheric pressure and the medium temperature, and convert them into 4-20 mA signals, which are aggregated to the programmable logic controller (12) for data calculation and analysis, and finally transmitted to the industrial control touch-screen integrated machine for storage and display.

2. A gas flow measurement system based on an axial flow fan collector structure according to claim 1, characterized in that: The impeller section (3) is composed of inlet guide vanes, moving blades and outlet guide vanes.

3. A gas flow measurement system based on an axial flow fan collector structure according to claim 2, characterized in that: The collector (2) is a tapered conical structure, and the collector tapers at an angle of β =40°~60°, the distance between the gas flow measurement section and the leading edge of the inlet guide vane l =0.2m~1m, and the velocity section uniformity index at the section γ v =0.92~1.

4. A gas flow measurement system based on an axial flow fan collector structure according to claim 1, characterized in that: The anti-blocking multi-point flute-shaped pipe pressure-taking device (5) is a composite flute-shaped pipe structure. The number of static pressure measuring points of a single pressure-taking pipe is n s =2~4, total number of pressure measurement points n d =2~6; and the number of pressure taking pipes is evenly distributed along the axial direction N =3~6.

5. The gas flow measurement system based on the axial flow fan collector structure according to claim 1 is characterized in that: The pressure-inducing pipeline (6) is made of 316L stainless steel pipe.

6. A gas flow measurement system based on an axial flow fan collector structure according to claim 1, characterized in that: The data of the flow measurement device is collected through the programmable logic controller, and the sampling cycle t s =0.5s~1.0s, the number of samples in each sampling cycle m ≥10, and the continuous sampling multi-point averaging method was used for data processing, as follows: The data set obtained by continuous sampling within a certain sampling period is { P i }, i =1,2,..., m , then the measured value after data processing at this moment is: 。 7. A gas flow measurement method based on an axial flow fan collector structure, characterized in that: The method is based on a gas flow measurement system based on an axial flow fan collector structure as described in claim 1, comprising: Adopt anti-blocking multi-point flute-shaped pressure-taking device to take pressure of the measuring section in real time; The dynamic and static pressures of the measurement section are collected and processed through the integrated pressure collection module of the local instrument cabinet, including data filtering and abnormal data elimination; The correction coefficient of the anti-blocking multi-point flute-type tube pressure-taking device is obtained through a standard laboratory platform, and high-precision numerical simulation calculations are carried out to obtain the velocity field coefficient of the flow measurement surface, and then the flow coefficient of the entire flow measurement device is obtained; The gas flow is calculated based on the built-in calculation program of the local programmable logic controller and uploaded in real time.

8. A gas flow measurement method based on an axial flow fan collector structure according to claim 7, characterized in that: The multi-point pressure tube correction coefficient is carried out on the standard laboratory platform, and high-precision numerical simulation calculations are carried out to obtain the velocity field coefficient of the flow measurement surface, and then the flow coefficient of the entire flow measurement device is obtained, as follows: The composite flute tube is calibrated on the fluid flow measurement platform in a standard closed pipeline to obtain the velocity correction factor ε ; According to the actual fan structure size, a full three-dimensional flow channel model is established, and numerical calculation analysis is carried out to calculate the working condition data. k ≥3, the fan inlet flow should cover the entire use range. At the same time, according to the measurement section distribution, the static pressure and total pressure values ​​at the measurement point of the measurement section under each calculation condition are extracted, that is, the calculation result data set {( Q v-cal , , , ) j }, j =1,2,..., k ; Based on the numerical simulation results {( Q v-cal , , , ) j }, the velocity field coefficient under each working condition is calculated by the relationship between flow rate and dynamic pressure of the measuring surface ζ j : Based on the calculation result data set {( , , ) j } Linear regression fitting is performed to obtain the relationship between the velocity field coefficient of the flow measurement section and the measured value ; Flow coefficient of the entire flow measurement device .

9. The gas flow measurement method based on the axial flow fan collector structure according to claim 7 is characterized in that: Speed ​​correction factor ε The value range is [0.8~1].

10. The gas flow measurement method based on the axial flow fan collector structure according to claim 7, characterized in that: The flow coefficient of the entire flow measurement device obtained based on calibration and digital simulation technology The actual volume flow rate of the medium is calculated based on the measured parameters Q v : 。

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