Grid type three-dimensional pitot tube smoke flow testing system and method

Abstract

The invention discloses a grid-type three-dimensional pitot tube flue gas flow testing system and a grid-type three-dimensional pitot tube flue gas flow testing method. Aiming at the problems of non-uniform flow field and irregular streamline of a large-section complex flue, the section of the flue is divided into a plurality of grids, a three-dimensional pitot tube is arranged at the center of each grid, and meanwhile, a subarea patrol measurement mode is adopted, a plurality of grids are set as a subarea, and a plurality of grids in each subarea are subjected to polling measurement. And multi-point flow field measurement is completed by using a limited number of pressure transmitters. The collected multi-dimensional flow velocity and static pressure data are fitted and integrated through the processing unit, and the overall flow of the flue gas is obtained. The large-cross-section flue gas flow measurement precision can be remarkably improved, meanwhile, the equipment investment is reduced, and the method is particularly suitable for carbon dioxide emission measurement and other scenes needing high-precision flow field monitoring.

Description

Technical Field

[0001] This invention belongs to the field of industrial flue gas flow measurement technology, and specifically relates to a grid-type three-dimensional Pitot tube flue gas flow testing system and method. Background Technology

[0002] In industrial production processes, accurate measurement of flue gas emissions is crucial for energy conservation, emission reduction, emissions accounting, and carbon trading. Conventional flue gas flow measurement methods include single-orifice Pitot tubes, multi-orifice sampling probes, and ultrasonic flow meters. Among these, Pitot tube measurement is widely used due to its simple structure and high reliability, but it suffers from the following drawbacks in large-section, complex flue gas ducts: 1. Insufficient measurement accuracy: The flow velocity distribution in the flue section is uneven, and a single point or a small number of sampling points are difficult to represent the overall flow rate; 2. Poor adaptability: Flue gas flow lines are often three-dimensionally irregularly distributed. Traditional Pitot tubes can only measure velocity in one direction and cannot reflect the complete flow field. 3. High system cost: If a full-section multi-point layout and simultaneous measurement are adopted, a large number of pressure transmitters and acquisition channels are required, which significantly increases equipment cost and maintenance.

[0003] Therefore, there is an urgent need for a flue gas flow testing method and system that balances measurement accuracy and system economy to meet the high-precision requirements of scenarios such as carbon emission monitoring.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to address the problems of insufficient accuracy, poor flow field adaptability, and high hardware cost in existing technologies for measuring flue gas flow in large-section, complex flue gas ducts, by providing a grid-based three-dimensional Pitot tube flue gas flow measurement system and method. Based on the technical features defined in the claims, this invention achieves high-precision coverage and measurement of complex three-dimensional flow fields by arranging a three-dimensional Pitot tube array at the center of the cross-sectional grid, employing zoned survey control, and combining signal transmission and numerical reconstruction algorithms, while significantly reducing the amount of expensive hardware such as pressure transmitters used in the system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A grid-based three-dimensional Pitot tube flue gas flow measurement system includes: Mesh generation unit, used to divide the cross-section of a large cross-section flue into multiple regular meshes; A three-dimensional Pitot tube array is positioned at the center of the grid. The partitioned survey module is used to divide several adjacent grids into a partition, and the 3D Pitot tubes within the partition are switched to the measurement channel sequentially by the controller; Data transmission lines are used to connect the three-dimensional Pitot tube to the pressure transmitter; The data acquisition and processing unit is used to receive and process the signals output by the pressure transmitter.

[0007] A further improvement of this invention is that the three-dimensional Pitot tube is a seven-well probe.

[0008] A further improvement of the present invention is that the grid is a square grid of 1m×1m.

[0009] A further improvement of this invention is that when the cross-section of the flue is irregular, invalid areas are eliminated by boundary trimming.

[0010] A further improvement of this invention is that the large cross-section flue grid is divided into sections with a grid combination of 3 m × 4 m.

[0011] A further improvement of the present invention is that the partitioned survey module includes a controller and a partitioned control program. The controller controls the sequential switching of the three-dimensional Pitot tubes within the partition, and the partitioned control program sets the survey sequence and time parameters.

[0012] A further improvement of the present invention is that the data acquisition and processing unit includes: a data preprocessing module for performing filtering, noise reduction and outlier correction; a data calculation module for calculating the cross-sectional flow field using fitting, interpolation or integration algorithms; and a result output module for outputting flow velocity and flow rate results.

[0013] A further improvement of the present invention is that the data transmission pipeline is made of high-temperature resistant and corrosion-resistant tubing.

[0014] A further improvement of the present invention is that the data transmission pipeline is provided with a purging and drainage interface.

[0015] A method for testing flue gas flow rate using a grid-type three-dimensional Pitot tube, the method being based on the aforementioned grid-type three-dimensional Pitot tube flue gas flow rate testing system, includes the following steps: Step 1: Establish a mesh model based on the cross-sectional dimensions of the flue, and place a 3D Pitot tube at the center of the mesh; Step 2: Set a partitioning scheme to divide multiple grids into several partitions; Step 3: Use the controller to sequentially switch the three-dimensional Pitot tubes within the partitions to acquire velocity components and hydrostatic signals; Step 4: Determine whether the partition data collection is complete. If not, continue the inspection. If complete, proceed to the next step. Step 5: Input the zone measurement data into the data acquisition and processing unit for preprocessing and numerical calculation to obtain the flow field distribution of the flue section; Step 6: Perform integration on the flow field to obtain the cross-sectional average velocity and the overall flue gas flow rate.

[0016] Compared with the prior art, the present invention has at least the following beneficial technical effects: This invention provides a grid-based three-dimensional Pitot tube flue gas flow testing system and method. By using gridded full-section coverage and direct measurement of the three velocity components by the three-dimensional Pitot tube, it can significantly reduce the spatial sampling uncertainty introduced by uneven velocity distribution and complex streamlines. The use of a zoned survey and switching device optimizes the hardware requirements for multi-point measurement through time-division multiplexing, significantly reducing the number of pressure transmitters and wiring complexity, thereby lowering initial investment and long-term maintenance costs. Multi-level data preprocessing and numerical reconstruction strategies improve the accuracy and stability of measurement results, meeting the needs of applications requiring high-precision flow input, such as carbon emission accounting. The system has a modular structure and flexible control strategy, facilitating engineering deployment and expansion under different flue gas duct sizes, shapes, and operating conditions. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart of the deployment and testing methods of the measurement system of the present invention.

[0019] Figure 2 This is a schematic diagram of the grid division of a large-section flue according to an embodiment of the present invention. Detailed Implementation

[0020] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0028] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0029] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] Example 1 like Figure 1 and Figure 2 As shown, the present invention provides a grid-type three-dimensional Pitot tube flue gas flow testing system, comprising: Mesh generation unit, used to divide the cross-section of a large cross-section flue into multiple regular meshes; A three-dimensional Pitot tube array is positioned at the center of the grid. The partitioned survey module is used to divide several adjacent grids into a partition, and the 3D Pitot tubes within the partition are switched to the measurement channel sequentially by the controller; Data transmission lines are used to connect the three-dimensional Pitot tube to the pressure transmitter; The data acquisition and processing unit is used to receive and process the signals output by the pressure transmitter.

[0031] In this embodiment, the three-dimensional pitot tube is a seven-well probe.

[0032] In this embodiment, the grid is a 1m×1m square grid.

[0033] In this embodiment, when the flue cross-section is irregular in shape, invalid areas are eliminated by boundary trimming.

[0034] In this embodiment, the large cross-section flue grid is divided into zones with a grid combination of 3 m × 4 m.

[0035] In this embodiment, the partitioned survey module includes a controller and a partitioned control program. The controller controls the sequential switching of the three-dimensional Pitot tubes within the partition, and the partitioned control program sets the survey sequence and time parameters.

[0036] In this embodiment, the data acquisition and processing unit includes: a data preprocessing module for performing filtering, noise reduction, and outlier correction; a data calculation module for calculating the cross-sectional flow field using fitting, interpolation, or integration algorithms; and a result output module for outputting flow velocity and flow rate results.

[0037] In this embodiment, the data transmission pipeline is made of high-temperature resistant and corrosion-resistant tubing.

[0038] In this embodiment, the data transmission pipeline is equipped with purging and drainage interfaces.

[0039] Example 2 like Figure 1 and Figure 2 As shown, the present invention provides a method for testing flue gas flow rate using a grid-type three-dimensional Pitot tube, comprising the following steps: Step 1: Establish a mesh model based on the cross-sectional dimensions of the flue, and place a 3D Pitot tube at the center of the mesh; Step 2: Set a partitioning scheme to divide multiple grids into several partitions; Step 3: Use the controller to sequentially switch the three-dimensional Pitot tubes within the partitions to acquire velocity components and hydrostatic signals; Step 4: Determine whether the partition data collection is complete. If not, continue the inspection. If complete, proceed to the next step. Step 5: Input the zone measurement data into the data acquisition and processing unit for preprocessing and numerical calculation to obtain the flow field distribution of the flue section; Step 6: Perform integration on the flow field to obtain the cross-sectional average velocity and the overall flue gas flow rate.

[0040] Example 3 like Figure 1As shown, the present invention provides a grid-based three-dimensional Pitot tube flue gas flow testing system, comprising several functional modules: a grid division unit, a three-dimensional Pitot tube array, a zoned monitoring module, a data transmission pipeline, and a data acquisition and processing unit. The grid division unit divides the large-section flue gas duct cross-section into several regular grids, preferably 1m×1m square units. The three-dimensional Pitot tube array preferably adopts a seven-hole probe structure, capable of acquiring velocity components and static pressure parameters in three directions of the flow field at a single point, thereby obtaining complete local three-dimensional velocity information. The zoned monitoring module combines several adjacent grids into a zone. Within the zone, measuring points are connected to a limited number of pressure transmitters in turn according to a preset monitoring sequence and time sequence via a controller, realizing the same pressure transmitter performing rotational measurements on multiple measuring points. The data transmission pipeline is responsible for reliably transmitting the signal output by the probe to the transmitter; the data acquisition and processing unit is responsible for signal acquisition, preprocessing, numerical reconstruction and result output. It mainly includes a data preprocessing module for filtering, denoising, outlier detection and correction; a data calculation module for interpolation, fitting and cross-sectional integral calculation; and a result output module for outputting average flow velocity, cross-sectional flow rate and CO2 emissions for carbon emission accounting.

[0041] At the methodological level, the present invention provides a grid-based three-dimensional Pitot tube flue gas flow test method, comprising: First, a 1m×1m grid model is established based on the flue cross-section dimensions, and the three-dimensional Pitot tubes are arranged. Second, a zoned survey plan is formulated, and the survey sequence and timing parameters (such as single-point steady-state observation time, switching time interval, sampling number of each zone, etc.) are preset in the controller. Then, the controller sequentially selects each grid in the zone, drives the switching device to connect the corresponding three-dimensional Pitot tubes to the pressure measurement channel, and collects velocity components and static pressure data. During the acquisition process, the data preprocessing module performs necessary filtering and outlier correction on the raw signal to ensure the reliability of subsequent reconstruction. After all grid data in a zone is collected, the data calculation module performs numerical interpolation or fitting reconstruction on the three-dimensional velocity components of each sampling point, and then performs numerical integration on the entire cross-section to calculate the total volumetric flow rate. If CO2 emissions need to be output, the obtained flow rate is combined with the concentration measurement value of the flue gas component analyzer to calculate the mass emission or equivalent emission.

[0042] Example 4 like Figure 1As shown, the present invention provides a grid-based three-dimensional Pitot tube flue gas flow testing system, mainly composed of grid division units, a three-dimensional Pitot tube array, a zoned survey module, data transmission pipelines, and a data acquisition and processing unit. In specific implementation, a two-dimensional grid model is first established for the cross-section of a large-section flue, preferably divided into square grid units with a side length of 1 meter, to ensure measurement accuracy while considering engineering feasibility. When the flue cross-section is irregular, invalid areas can be eliminated by boundary trimming, and the grid is only deployed within the effective flow area to avoid wasting probe resources. Subsequently, a three-dimensional Pitot tube is placed at the center of the grid within each zone, preferably using a seven-hole probe structure. This probe can simultaneously acquire the three velocity components of the flow field and local static pressure, exhibiting stronger adaptability and measurement accuracy than traditional single-hole or five-hole probes, and is particularly suitable for complex flue environments with vortices, secondary flows, and turbulence.

[0043] To reduce hardware costs and the number of pressure transmitters used, this invention further introduces a partitioned survey mechanism. This involves dividing several adjacent grids into a partition, such as... Figure 2 As shown, in the preferred embodiment of this invention, the large-section flue grid is divided into 3×4 grids as a partition, and a controller is configured in the partition. The controller controls the three-dimensional Pitot tubes in the partition to switch to each grid sequentially according to a preset survey program, so that a limited number of pressure transmitters can sequentially collect data from all measuring points in the partition. The survey strategy can be executed in a fixed cycle or dynamically adjusted according to the historical fluctuation characteristics of the flow field. For example, the sampling frequency can be increased in areas with large velocity fluctuations, while the sampling density can be appropriately reduced in relatively stable areas, thereby improving measurement efficiency while ensuring accuracy. Each three-dimensional Pitot tube is connected to the survey device through a high-temperature and corrosion-resistant pneumatic pipeline. If necessary, purging and drainage interfaces are set on the pipeline to prevent condensate or dust accumulation from interfering with signal transmission.

[0044] The acquired pressure signal is converted by a pressure transmitter and then input to the data acquisition and processing unit. In this unit, the data preprocessing module first filters, denoises, performs zero-point correction, and removes outliers from the raw signal to ensure data accuracy and stability. Then, the data calculation module uses polynomial fitting, interpolation, or integration algorithms to spatially reconstruct the velocity data from a limited number of measuring points, obtaining the flow field distribution across the entire cross-section. Finally, the results output module performs integral calculations on the flow field to calculate the average flow velocity and overall flue gas flow rate, and, when necessary, combines gas concentration data to further estimate carbon dioxide emissions. The results can be displayed locally or output via an industrial communication interface or a remote data platform for carbon emission accounting, energy efficiency assessment, and operational monitoring.

[0045] At the methodological level, the testing process proposed in this invention is highly compatible with the system. First, a mesh model is established and three-dimensional Pitot tubes are arranged based on the flue cross-sectional dimensions. Second, a zoning scheme is formulated, and the survey sequence and time parameters are set within the controller. Then, the controller sequentially connects probes within each zone and collects three-dimensional velocity components and static pressure data. After completing data acquisition for one grid, the process switches to the next grid until the entire zone is covered. After acquisition, the data is uniformly transmitted to the data acquisition and processing unit for preprocessing, fitting, and flow field reconstruction. Finally, the average flow velocity, overall flow rate, and carbon dioxide emissions are calculated through integration. The entire process ensures comprehensive coverage of complex flue flow fields while significantly reducing hardware investment and maintenance costs.

[0046] In summary, the grid-type three-dimensional Pitot tube flue gas flow measurement system and method proposed in this invention can achieve high-precision, low-cost, and scalable flow measurement in large-section complex flues. It is particularly suitable for applications with extremely high data accuracy requirements, such as carbon dioxide emission monitoring and energy efficiency assessment, and has significant engineering application value and promotion significance.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0048] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A grid-based three-dimensional Pitot tube flue gas flow testing system, characterized in that, include: Mesh generation unit, used to divide the cross-section of a large cross-section flue into multiple regular meshes; A three-dimensional Pitot tube array is positioned at the center of the grid. The partitioned survey module is used to divide several adjacent grids into a partition, and the 3D Pitot tubes within the partition are switched to the measurement channel sequentially by the controller; Data transmission lines are used to connect the three-dimensional Pitot tube to the pressure transmitter; The data acquisition and processing unit is used to receive and process the signals output by the pressure transmitter.

2. The grid-type three-dimensional Pitot tube flue gas flow testing system according to claim 1, characterized in that, The three-dimensional Pitot tube is a seven-well probe.

3. The grid-type three-dimensional Pitot tube flue gas flow testing system according to claim 1, characterized in that, The grid is a 1m × 1m square grid.

4. The grid-type three-dimensional Pitot tube flue gas flow testing system according to claim 1, characterized in that, When the flue cross-section is irregular in shape, invalid areas are eliminated by boundary trimming.

5. The grid-type three-dimensional Pitot tube flue gas flow testing system according to claim 1, characterized in that, The grid division of large cross-section flues is based on a 3 m × 4 m grid combination as one zone.

6. The grid-type three-dimensional Pitot tube flue gas flow testing system according to claim 1, characterized in that, The zone survey module includes a controller and a zone control program. The controller controls the sequential switching of the 3D Pitot tubes within the zone, and the zone control program sets the survey sequence and time parameters.

7. The grid-type three-dimensional Pitot tube flue gas flow testing system according to claim 1, characterized in that, The data acquisition and processing unit includes: a data preprocessing module for performing filtering, noise reduction, and outlier correction; a data calculation module for calculating the cross-sectional flow field using fitting, interpolation, or integration algorithms; and a result output module for outputting flow velocity and flow rate results.

8. The grid-type three-dimensional Pitot tube flue gas flow testing system according to claim 1, characterized in that, The data transmission pipeline is made of high-temperature resistant and corrosion-resistant tubing.

9. A grid-type three-dimensional Pitot tube flue gas flow testing system according to claim 8, characterized in that, The data transmission line is equipped with purging and drainage interfaces.

10. A method for measuring flue gas flow rate using a grid-type three-dimensional Pitot tube, characterized in that, This method, based on a grid-type three-dimensional Pitot tube flue gas flow testing system according to any one of claims 1 to 9, includes the following steps: Step 1: Establish a mesh model based on the cross-sectional dimensions of the flue, and place a 3D Pitot tube at the center of the mesh; Step 2: Set a partitioning scheme to divide multiple grids into several partitions; Step 3: Use the controller to sequentially switch the three-dimensional Pitot tubes within the partitions to acquire velocity components and hydrostatic signals; Step 4: Determine whether the partition data collection is complete. If not, continue the inspection. If complete, proceed to the next step. Step 5: Input the zone measurement data into the data acquisition and processing unit for preprocessing and numerical calculation to obtain the flow field distribution of the flue section; Step 6: Perform integration on the flow field to obtain the cross-sectional average velocity and the overall flue gas flow rate.

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