Method of arranging a multi-path ultrasonic flow meter for a circular chimney and related apparatus

Abstract

The application discloses a kind of multi-channel ultrasonic flowmeter arrangement method for circular chimney and related equipment, belong to gas flow monitoring technical field, this method is based on the arrangement concept of multi-channel, divide into equal-area multiple annulus to circular section, select multiple groups of flowmeter arrangement points on chimney inner wall, form corresponding projection chord length on section between each group of arrangement points, projection chord length is divided into several line segments by each annulus, the total length of line segment is weighted, finally through the judgment of weighted length satisfying preset threshold condition, corresponding flowmeter arrangement point is output, to complete multi-channel ultrasonic flowmeter arrangement;Using this method can ensure the accuracy of flue gas flow measurement for circular chimney;The design principle of this method is similar to the principle of equal-area method for non-uniform flow field, has the advantages such as measurement accuracy, strong adaptability to non-uniform flow field.

Description

Technical Field

[0001] This invention belongs to the field of gas flow monitoring technology, specifically relating to a method for arranging multi-channel ultrasonic flow meters for circular chimneys and related equipment. Background Technology

[0002] With rapid economic development, the demand for accurate measurement of flue gas emissions from chimneys is becoming increasingly urgent in various industrial sectors, in order to further achieve energy conservation, safe production, and pollution control. To meet the ever-increasing requirements for gas flow measurement accuracy, ultrasonic technology has been applied to gas flow detection.

[0003] For measuring flow velocity inside a circular chimney, the conventional engineering practice is to arrange a pair of ultrasonic transducers along the diameter, with the receiver positioned downstream of the transmitter. However, for chimneys with circular cross-sections, uneven flue gas velocity distribution is common, and the flow characteristics within a circular pipe generally result in higher velocity at the chimney center and lower velocity near the pipe wall. Therefore, simply using a single-channel ultrasonic gas flow meter to measure the average linear velocity along the diameter cannot represent the average flue gas velocity across the entire cross-section. Currently, for measuring the average velocity in a non-uniform flow field across a circular cross-section, a better approach is to first divide the flow into loops using the equal-area method, then measure the velocity in each loop separately. The average velocity of each loop is then the average velocity of the entire cross-section. According to this measurement principle, if the linear average velocity is measured along the diameter direction, when the flow velocity at the center of the chimney is too high, the measured value of the conventional ultrasonic gas flow meter will also be too high. It is necessary to reduce the measurement deviation through on-site calibration, that is, to use a calibration coefficient for correction. However, since the degree of excess of the flow velocity at the center of the chimney is not consistent under different flow velocities, it is difficult to use a fixed calibration coefficient for correction. Therefore, this type of measurement method cannot guarantee the accuracy of flow measurement in the non-homogeneous flow field of a circular chimney. Summary of the Invention

[0004] To overcome the shortcomings of the above-mentioned technologies, the present invention provides a method for arranging multi-channel ultrasonic flow meters for circular chimneys and related equipment. This arrangement method can solve the technical problem that existing measurement methods cannot guarantee measurement accuracy for the non-homogeneous flow field of circular chimneys.

[0005] To achieve the above objectives, the present invention employs the following technical content:

[0006] A method for arranging multi-channel ultrasonic flow meters for circular chimneys includes:

[0007] S1: Obtain any cross-section of the circular chimney, and divide the cross-section into multiple equal-area rings based on the equal-ring area method;

[0008] S2: Select multiple sets of flow meter placement points on the inner wall of the chimney. The lines connecting each set of placement points form a corresponding projected chord length on the cross section. The projected chord length is divided into several line segments by each ring.

[0009] S3: Weight the total length of the line segment corresponding to each ring to obtain the corresponding weighted total length, and output the multiple sets of flow meter placement points corresponding to the weighted total length under the condition that the weighted total length meets the preset threshold, so as to complete the multi-channel ultrasonic flow meter placement.

[0010] Furthermore, the specific steps are as follows:

[0011] In S1, the cross section is divided into three rings with equal areas: an inner ring, a middle ring, and an outer ring, based on the equal ring area method.

[0012] In S2, the first group of flowmeter placement points is selected. The first projected chord length formed by the lines connecting the corresponding two points on the cross section passes through all the rings. The first projected chord length is divided into 5 segments: the first outer ring segment I, the first middle ring segment I, the first inner ring segment, the first middle ring segment II, and the first outer ring segment II. The second group of flowmeter placement points is selected. The second projected chord length formed by the lines connecting the corresponding two points on the cross section passes only through the middle and outer rings. The second projected chord length is divided into 3 segments: the second outer ring segment I, the second middle ring segment, and the second outer ring segment II. The third group of flowmeter placement points is selected. The projected chord length formed by the lines connecting the corresponding two points on the cross section passes only through the middle and outer rings. The third projected chord length formed by the lines connecting the corresponding two points on the cross section passes only through the middle and outer rings. The third projected chord length is divided into 3 segments: the third outer ring segment I, the third middle ring segment, and the third outer ring segment II. The first projected chord length is perpendicular to the second and third projected chord lengths, respectively.

[0013] In S3, the total length of the line segments corresponding to the inner ring is the first inner ring line segment; the total length of the line segments corresponding to the middle ring is the sum of the first middle ring line segment I, the first middle ring line segment II, the second middle ring line segment, and the third middle ring line segment; the total length of the line segments corresponding to the outer ring is the sum of the first outer ring line segment I, the first outer ring line segment II, the second outer ring line segment I, the second outer ring line segment II, the third outer ring line segment I, and the third outer ring line segment II. The total lengths of the line segments corresponding to the inner ring, the middle ring, and the outer ring are weighted to obtain the weighted lengths of the inner ring, the middle ring, and the outer ring. It is determined whether the three weighted lengths meet the preset threshold conditions. If they do, three sets of flow meter placement points are output; otherwise, the flow meter placement points are reselected until the preset threshold conditions are met.

[0014] Furthermore, the preset threshold condition is:

[0015] In the three weighted lengths, the absolute value of the deviation between any two weighted lengths does not exceed 10%.

[0016] Furthermore, the multi-channel ultrasonic flow meters are arranged according to the three sets of flow meter arrangement points output; wherein, the multi-channel ultrasonic flow meter includes a transmitting end and a receiving end; the three transmitting ends are arranged on the same cross section located upstream of the chimney, and the three receiving ends are arranged on the same cross section located downstream of the chimney.

[0017] Furthermore, the weighted formulas for the total lengths of the line segments corresponding to the inner ring, the middle ring, and the outer ring are as follows:

[0018] Inner ring weighted length = first inner ring segment * first weight coefficient;

[0019] The weighted length of the middle ring is calculated as follows: First middle ring segment I * First weight coefficient + First middle ring segment II * First weight coefficient + Second middle ring segment * Second weight coefficient + Third middle ring segment * Third weight coefficient.

[0020] The weighted length of the outer ring is calculated as follows: First outer ring segment I * First weight coefficient + First outer ring segment II * First weight coefficient; Second outer ring segment I * Second weight coefficient + Second outer ring segment II * Second weight coefficient + Third outer ring segment I * Third weight coefficient + Third outer ring segment * Third weight coefficient.

[0021] Furthermore, the first weighting coefficient corresponding to the first projection chord length is 0.428; and the second weighting coefficient and the third weighting coefficient corresponding to the second projection chord length and the third projection chord length are both 0.286.

[0022] Furthermore, when the first projected chord length is equal to the chimney diameter D, and the second and third projected chord lengths are all equal to 0.66D, the inner ring weighted length, the middle ring weighted length, and the outer ring weighted length are 0.577D, 0.879D, and 0.864D, respectively.

[0023] A multi-channel ultrasonic flow meter arrangement system for a circular chimney, comprising the steps of the above-described multi-channel ultrasonic flow meter arrangement method for a circular chimney, including:

[0024] The cross-section segmentation module is used to obtain any cross-section of a circular chimney and divide the cross-section into multiple equal-area rings based on the equal-ring area method.

[0025] The point selection module is used to select multiple sets of flow meter placement points on the inner wall of the chimney. The lines connecting each set of placement points form a corresponding projected chord length on the cross section. The projected chord length is divided into several line segments by each ring.

[0026] The calculation and judgment module is used to perform weighted processing on the total length of the line segment corresponding to each ring to obtain the corresponding weighted total length. It outputs multiple sets of flow meter placement points corresponding to the condition that the weighted total length meets the preset threshold, so as to complete the placement of multi-channel ultrasonic flow meters.

[0027] An apparatus comprising:

[0028] Memory, used to store computer programs;

[0029] A processor is used to execute the computer program to implement the steps of the above-described method for arranging multi-channel ultrasonic flow meters for circular chimneys.

[0030] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the above-described method for arranging multi-channel ultrasonic flow meters for a circular chimney.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] This invention provides a method for arranging multi-channel ultrasonic flow meters for circular chimneys. Based on the concept of multi-channel arrangement, the circular cross-section is divided into multiple rings of equal area. Multiple sets of flow meter placement points are selected on the inner wall of the chimney. The lines connecting each set of placement points form a corresponding projected chord length on the cross-section. The projected chord length is divided into several line segments by each ring. The total length of the line segments is weighted, and the corresponding flow meter placement points are output based on whether the weighted length meets a preset threshold condition, thus completing the multi-channel ultrasonic flow meter arrangement. This method ensures the accuracy of flue gas flow measurement for circular chimneys. The design principle of this method is similar to the principle of the equal-area method for non-uniform flow fields, and it has significant advantages such as accurate measurement and strong adaptability to non-uniform flow fields.

[0033] Preferably, in this invention, the multi-channel ultrasonic flow meter is arranged according to the three sets of flow meter arrangement points output; wherein, the multi-channel ultrasonic flow meter includes a transmitting end and a receiving end; the three transmitting ends are arranged on the same cross section located upstream of the chimney, and the three receiving ends are arranged on the same cross section located downstream of the chimney. In this way, only two sets of detection platforms need to be arranged on the inner wall of the chimney, instead of arranging multiple sets, which not only improves work efficiency, but also saves space and deployment and maintenance costs. Attached Figure Description

[0034] Figure 1 A schematic diagram of the arrangement of multi-channel ultrasonic flow meters on the cross-section of a circular chimney provided in an embodiment of the present invention;

[0035] Figure 2 A flowchart of a method for arranging multi-channel ultrasonic flow meters for circular chimneys provided by the present invention.

[0036] Figure 3 This is a schematic diagram of the structure of the multi-channel ultrasonic flow meter arrangement system for a circular chimney provided by the present invention.

[0037] Figure label:

[0038] First main channel transmitter transducer-1; First main channel receiver transducer-2; Second main channel transmitter transducer-3; Second main channel receiver transducer-4; Third main channel transmitter transducer-5; Third main channel receiver transducer-6. Detailed Implementation

[0039] This invention provides a method for arranging multi-channel ultrasonic flow meters for circular chimneys, such as... Figure 2 As shown, it includes the following steps:

[0040] S1: Obtain any cross-section of the circular chimney and divide the cross-section into multiple equal-area rings based on the equal-ring area method.

[0041] S2: Select multiple sets of flow meter placement points on the inner wall of the chimney. The lines connecting each set of placement points form a corresponding projected chord length on the cross section. The projected chord length is divided into several line segments by each ring.

[0042] S3: Weight the total length of the line segment corresponding to each ring to obtain the corresponding weighted total length, and output the multiple sets of flow meter placement points corresponding to the weighted total length under the condition that the weighted total length meets the preset threshold, so as to complete the multi-channel ultrasonic flow meter placement.

[0043] The specific steps are as follows:

[0044] In S1, the cross section is divided into three rings with equal areas: an inner ring, a middle ring, and an outer ring, based on the equal ring area method.

[0045] In S2, the first group of flowmeter placement points is selected. The first projected chord length formed by the line connecting the corresponding two points on the cross section passes through all the rings. The first projected chord length is divided into 5 line segments: the first outer ring segment I, the first middle ring segment I, the first inner ring segment, the first middle ring segment II, and the first outer ring segment II. The second group of flowmeter placement points is selected. The second projected chord length formed by the line connecting the corresponding two points on the cross section passes only through the middle and outer rings. The second projected chord length is divided into 3 line segments: the second outer ring segment I, the second middle ring segment, and the second outer ring segment II. The third group of flowmeter placement points is selected. The projected chord length formed by the line connecting the corresponding two points on the cross section passes only through the middle and outer rings. The third projected chord length formed by the line connecting the corresponding two points on the cross section passes only through the middle and outer rings. The third projected chord length is divided into 3 line segments: the third outer ring segment I, the third middle ring segment, and the third outer ring segment II. The first projected chord length is perpendicular to the second and third projected chord lengths, respectively.

[0046] In S3, the total length of the line segments corresponding to the inner ring is the first inner ring line segment; the total length of the line segments corresponding to the middle ring is the sum of the first middle ring line segment I, the first middle ring line segment II, the second middle ring line segment, and the third middle ring line segment; the total length of the line segments corresponding to the outer ring is the sum of the first outer ring line segment I, the first outer ring line segment II, the second outer ring line segment I, the second outer ring line segment II, the third outer ring line segment I, and the third outer ring line segment II. The total lengths of the line segments corresponding to the inner ring, the middle ring, and the outer ring are weighted to obtain the weighted lengths of the inner ring, the middle ring, and the outer ring. It is determined whether the three weighted lengths meet the preset threshold conditions. If they do, three sets of flow meter placement points are output; otherwise, the flow meter placement points are reselected until the preset threshold conditions are met.

[0047] The above-mentioned preset threshold conditions are:

[0048] In the three weighted lengths, the absolute value of the deviation between any two weighted lengths does not exceed 10%.

[0049] The multi-channel ultrasonic flow meter is arranged according to the three sets of flow meter placement points output; wherein, the multi-channel ultrasonic flow meter includes a transmitting end and a receiving end; the three transmitting ends are arranged on the same cross section located upstream of the chimney, and the three receiving ends are arranged on the same cross section located downstream of the chimney.

[0050] The weighted formulas for the total lengths of the line segments corresponding to the inner ring, the middle ring, and the outer ring are as follows:

[0051] Inner ring weighted length = first inner ring segment * first weight coefficient;

[0052] The weighted length of the middle ring is calculated as follows: First middle ring segment I * First weight coefficient + First middle ring segment II * First weight coefficient + Second middle ring segment * Second weight coefficient + Third middle ring segment * Third weight coefficient.

[0053] The weighted length of the outer ring is calculated as follows: First outer ring segment I * First weight coefficient + First outer ring segment II * First weight coefficient; Second outer ring segment I * Second weight coefficient + Second outer ring segment II * Second weight coefficient + Third outer ring segment I * Third weight coefficient + Third outer ring segment * Third weight coefficient.

[0054] The first weighting coefficient corresponding to the first projection chord length is 0.428; the second weighting coefficient and the third weighting coefficient corresponding to the second projection chord length and the third projection chord length are both 0.286.

[0055] When the first projected chord length is equal to the chimney diameter D, and the second and third projected chord lengths are all equal to 0.66D, the inner ring weighted length, middle ring weighted length, and outer ring weighted length are calculated to be 0.577D, 0.879D, and 0.864D respectively, using the weighted processing formula.

[0056] like Figure 3 As shown, the present invention also provides a multi-channel ultrasonic flow meter arrangement system for a circular chimney, comprising:

[0057] The cross-section segmentation module is used to obtain any cross-section of a circular chimney and divide the cross-section into multiple equal-area rings based on the equal-ring area method. The point selection module is used to select multiple sets of flow meter placement points on the inner wall of the chimney. The lines connecting each set of placement points form a corresponding projected chord length on the cross-section, and the projected chord length is divided into several line segments by each ring. The calculation and judgment module is used to perform weighted processing on the total length of the line segments corresponding to each ring to obtain the corresponding weighted total length. It outputs multiple sets of flow meter placement points corresponding to the condition that the weighted total length meets the preset threshold, so as to complete the multi-channel ultrasonic flow meter placement.

[0058] The present invention also provides an apparatus comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the method for arranging a multi-channel ultrasonic flow meter for a circular chimney.

[0059] When the processor executes the computer program, it implements the steps described above for arranging multi-channel ultrasonic flow meters for a circular chimney. For example, it obtains any cross-section of the circular chimney and divides the cross-section into multiple equal-area rings based on the equal-ring area method; selects multiple sets of flow meter arrangement points on the inner wall of the chimney, wherein the lines connecting each set of arrangement points form a corresponding projected chord length on the cross-section, and the projected chord length is divided into several line segments by each ring; it performs weighted processing on the total length of the line segments corresponding to each ring to obtain the corresponding weighted total length, and outputs the multiple sets of flow meter arrangement points corresponding to the condition that the weighted total length meets the preset threshold, so as to complete the multi-channel ultrasonic flow meter arrangement.

[0060] Alternatively, when the processor executes the computer program, it implements the functions of each module in the above system, such as: a cross-section segmentation module, used to obtain any cross-section of a circular chimney and divide the cross-section into multiple equal-area rings based on the equal-ring area method; a point selection module, used to select multiple sets of flow meter placement points on the inner wall of the chimney, wherein the lines connecting each set of placement points form a corresponding projected chord length on the cross-section, and the projected chord length is divided into several line segments by each ring; and a calculation and judgment module, used to perform weighted processing on the total length of the line segments corresponding to each ring to obtain the corresponding weighted total length, and output the multiple sets of flow meter placement points corresponding to the condition that the weighted total length meets the preset threshold, so as to complete the multi-channel ultrasonic flow meter placement.

[0061] For example, the computer program can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing preset functions, the instruction segments describing the execution process of the computer program in the multi-channel ultrasonic flow meter placement device for a circular chimney. For example, the computer program can be divided into a cross-section segmentation module, a point selection module, and a calculation and judgment module; the specific functions of each module are as follows: the cross-section segmentation module is used to obtain any cross-section of the circular chimney and divide the cross-section into multiple equal-area rings based on the equal-ring area method; the point selection module is used to select multiple sets of flow meter placement points on the inner wall of the chimney, wherein the lines connecting each set of placement points form a corresponding projected chord length on the cross-section, and the projected chord length is divided into several line segments by each ring; the calculation and judgment module is used to perform weighted processing on the total length of the line segments corresponding to each ring to obtain the corresponding weighted total length, and output the multiple sets of flow meter placement points corresponding to the condition that the weighted total length meets a preset threshold, so as to complete the multi-channel ultrasonic flow meter placement.

[0062] The multi-channel ultrasonic flow meter arrangement device for a circular chimney can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. The multi-channel ultrasonic flow meter arrangement device for a circular chimney may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the above are examples of multi-channel ultrasonic flow meter arrangement devices for circular chimneys and do not constitute a limitation on such devices. The device may include more components than described above, or combine certain components, or use different components. For example, the multi-channel ultrasonic flow meter arrangement device for a circular chimney may also include input / output devices, network access devices, buses, etc.

[0063] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or any conventional processor. This processor is the control center for the multi-channel ultrasonic flow meter arrangement for the circular chimney, connecting all parts of the multi-channel ultrasonic flow meter arrangement equipment for the circular chimney using various interfaces and lines.

[0064] The memory can be used to store the computer program and / or modules. The processor implements various functions of the multi-channel ultrasonic flow meter arrangement device for circular chimneys by running or executing the computer program and / or modules stored in the memory and calling the data stored in the memory.

[0065] The memory may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a given function (such as sound playback or image playback). The data storage area may store data created based on the use of the mobile phone (such as audio data and phonebook entries). Furthermore, the memory may include high-speed random access memory and non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital cards (SD), flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0066] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method for arranging a multi-channel ultrasonic flow meter for a circular chimney.

[0067] If the modules / units of the multi-channel ultrasonic flow meter arrangement system for circular chimneys are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0068] Based on this understanding, the present invention can implement all or part of the processes in the above-described method for arranging multi-channel ultrasonic flow meters for circular chimneys, or it can be accomplished by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above-described method for arranging multi-channel ultrasonic flow meters for circular chimneys. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or preset intermediate forms, etc.

[0069] The computer-readable storage medium may include any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0070] It should be noted that the content contained in the computer-readable storage medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0071] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0072] Example

[0073] As mentioned in the background section, the conventional engineering practice for measuring flow velocity inside a circular chimney is to arrange a pair of ultrasonic transducers along the diameter, with the receiver positioned downstream of the transmitter. However, for chimneys with circular cross-sections, uneven flue gas velocity distribution is common, and the flow characteristics within a circular pipe generally result in higher velocity at the chimney center and lower velocity near the pipe wall. Therefore, simply using a single-channel ultrasonic gas flow meter to measure the average linear velocity along the diameter cannot represent the average flue gas velocity across the entire cross-section. Currently, the preferred method for measuring the average velocity in a non-uniform flow field across a circular cross-section is to first divide the flow into loops using the equal-area method, then measure the velocity in each loop separately. The average velocity of each loop is then the average velocity of the entire cross-section. Based on this measurement principle, if the linear average velocity is measured along the diameter direction, the measured value of a conventional ultrasonic gas flow meter will also be too high when the flow velocity at the center of the chimney is too high. It is necessary to reduce the measurement deviation through on-site calibration, that is, to use a calibration coefficient for correction. However, since the degree of excess flow velocity at the center of the chimney is not consistent under different flow velocities, it is difficult to use a fixed calibration coefficient for correction, resulting in poor measurement accuracy.

[0074] To address the aforementioned issues, this embodiment provides a method for arranging multi-channel ultrasonic flow meters for circular chimneys. This method solves the problem that current measurement methods cannot guarantee accuracy under non-uniform flow fields.

[0075] To facilitate a clearer understanding of this embodiment, the following technical terms will be explained first:

[0076] Ultrasonic gas flow meters are designed based on the principle of sound velocity difference during ultrasonic wave propagation. Specifically, they calculate the gas velocity and flow rate by measuring the difference in sound velocity between the forward and reverse propagation directions of the ultrasonic flow. Compared to commonly used differential pressure flow meters, ultrasonic gas flow meters have a significant advantage in that they have a wider measurement range. After calibration, they can achieve Class 1 accuracy within a flow velocity range of 0.3-30 m / s, with a range ratio of 1:100.

[0077] The main component of an ultrasonic gas flow meter is the ultrasonic transducer, which has a transmitting end and a receiving end. The measured value is the average gas velocity along the line connecting the transmitting and receiving ends. Generally, for flow velocity measurement inside a circular chimney, the standard engineering practice is to arrange a pair of ultrasonic transducers along the diameter, with the receiving end located downstream of the transmitting end.

[0078] This embodiment provides a method for arranging multi-channel ultrasonic flow meters for circular chimneys, combined with... Figure 1 Explanation:

[0079] like Figure 1 As shown in Figure 1, A is the inner ring, B is the middle ring, and C is the outer ring. A multi-channel ultrasonic flow meter for circular chimneys includes a pair of main channel ultrasonic transducers and two pairs of auxiliary channel transducers. The pair of main channel ultrasonic transducers consists of a first main channel transmitter transducer 1 and a first main channel receiver transducer 2. The pair of auxiliary channel ultrasonic transducers consists of a second main channel transmitter transducer 3 and a second main channel receiver transducer 4, respectively. The other pair consists of a third main channel transmitter transducer 5 and a third main channel receiver transducer 6. As shown in Figure 1, the transmitter and receiver of the main channel ultrasonic transducers... The chord length of the line connecting the transmitting and receiving ends projected onto the circular cross-section of the chimney is L1, and the output signal is M1. The chord lengths of the line connecting the transmitting and receiving ends of the auxiliary channel ultrasonic transducer projected onto the circular cross-section of the chimney are L2 and L3, respectively, and the corresponding output signals are M2 and M3, respectively. The diameter of the circular cross-section of the chimney is D, where L1 = D, L2 = L3 = (0.66 ± 0.1) * D. The chord corresponding to chord length L1 is perpendicular to the chords corresponding to chord lengths L2 and L3. The output signal of the multi-channel ultrasonic flow meter is (0.57 * M1 + 0.215 * M2 + 0.215 * M3).

[0080] This paper provides a method for arranging multi-channel ultrasonic flow meters for circular chimneys, the specific steps of which are as follows:

[0081] The first step is to create a 3D model of the circular chimney and obtain any cross-section. Based on the equal-area method, the cross-section is divided into an inner ring A, a middle ring B, and an outer ring C, which are three equal-area rings.

[0082] The second step involves selecting the first set of flowmeter placement points. The first projected chord length L1 formed by the lines connecting the corresponding two points on the cross-section passes through all the rings (inner ring A, middle ring B, and outer ring C). The first projected chord length L1 is divided into 5 segments: the first outer ring segment I, the first middle ring segment I, the first inner ring segment, the first middle ring segment II, and the first outer ring segment II. The second set of flowmeter placement points is then selected. The second projected chord length L2 formed by the lines connecting the corresponding two points on the cross-section only passes through the middle and outer rings. The second projected chord length L2 is divided into 3 segments. The line segments are the second outer ring segment I, the second middle ring segment, and the second outer ring segment II, respectively. A third set of flow meter placement points is selected, and the projected chord length formed by the line connecting the corresponding two points on the cross section only passes through the middle ring and the outer ring. The third projected chord length L3 formed by the line connecting the corresponding two points on the cross section only passes through the middle ring and the outer ring. The third projected chord length L3 is divided into 3 line segments, namely the third outer ring segment I, the third middle ring segment, and the third outer ring segment II, respectively. The first projected chord length L1 is perpendicular to the second projected chord length L2 and the third projected chord length L3, respectively.

[0083] The third step involves calculating the total length of the line segments corresponding to inner ring A as the first inner ring line segment; the total length of the line segments corresponding to middle ring B as the sum of the first middle ring line segment I, the first middle ring line segment II, the second middle ring line segment, and the third middle ring line segment; and the total length of the line segments corresponding to outer ring C as the sum of the first outer ring line segment I, the first outer ring line segment II, the second outer ring line segment I, the second outer ring line segment II, the third outer ring line segment I, and the third outer ring line segment II. The total lengths of the line segments corresponding to inner ring A, middle ring B, and outer ring C are weighted to obtain the weighted lengths of inner ring A, middle ring B, and outer ring C. It is then determined whether these three weighted lengths meet the preset threshold conditions. If they do, three sets of flow meter placement points are output; otherwise, flow meter placement points are reselected until the preset threshold conditions are met.

[0084] Here, it is determined that the projection chord lengths of the lines connecting the transmitting and receiving transducers of the three pairs of ultrasonic transducers in the final arrangement are approximately equal after weighting the total lengths of the line segments in the three equal-area rings (with a deviation of no more than ±10%) on the circular cross-section of the chimney.

[0085] like Figure 1As shown, the diameter of the circular cross-section of the chimney is D, where L1 = D, L2 = L3 = (0.66 ± 0.1) * D. The weighting coefficients for L1, L2, and L3 are 0.428, 0.286, and 0.286, respectively, and the sum of the weighting coefficients is 1. The chord with length L1 is perpendicular to the chords with lengths L2 and L3. When L1 = D and L2 = L3 = 0.66 * D, the total lengths of the line segments of the inner ring, middle ring, and outer ring are 0.577D, 0.879D, and 0.864D, respectively, and after weighting, they are 0.247D, 0.251D, and 0.247D, with a deviation not exceeding ±10%.

[0086] Thus, when the multi-channel ultrasonic flow meter is arranged using the above method, the output signal of the multi-channel ultrasonic flow meter is (0.428*M1+0.286*M2+0.286*M3).

[0087] Furthermore, once the location for adding the sound channel is determined, it can be directly modified from an existing conventional mono-channel ultrasonic flow meter on site.

[0088] In summary, this embodiment provides a method for arranging multi-channel ultrasonic flow meters for circular chimneys. Compared with existing measurement methods, this method has the following advantages:

[0089] This method is based on the concept of multi-channel layout. The circular cross-section is divided into multiple rings of equal area. Multiple sets of flowmeter placement points are selected on the inner wall of the chimney. The lines connecting each set of placement points form a corresponding projected chord length on the cross-section. This projected chord length is divided into several line segments by each ring. The total length of the line segments is weighted, and the corresponding flowmeter placement points are output based on whether the weighted length meets a preset threshold condition, thus completing the multi-channel ultrasonic flowmeter layout. This method ensures the accuracy of flue gas flow measurement for circular chimneys. The design principle of this method is similar to the equal-area method for non-uniform flow fields, and it has significant advantages such as accurate measurement and strong adaptability to non-uniform flow fields.

[0090] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A method for arranging multi-channel ultrasonic flow meters for circular chimneys, characterized in that, include: S1: Obtain any cross-section of the circular chimney, and divide the cross-section into multiple equal-area rings based on the equal-ring area method; S2: Select multiple sets of flow meter placement points on the inner wall of the chimney. The lines connecting each set of placement points form a corresponding projected chord length on the cross section. The projected chord length is divided into several line segments by each ring. S3: Weight the total length of the line segment corresponding to each ring to obtain the corresponding weighted total length, and output the multiple sets of flow meter placement points corresponding to the weighted total length under the condition that the weighted total length meets the preset threshold, so as to complete the multi-channel ultrasonic flow meter placement. The specific steps are as follows: In S1, the cross section is divided into three rings with equal areas: an inner ring, a middle ring, and an outer ring, based on the equal ring area method. In S2, the first group of flowmeter placement points is selected. The first projected chord length formed by the lines connecting the corresponding two points on the cross section passes through all the rings. The first projected chord length is divided into 5 segments: the first outer ring segment I, the first middle ring segment I, the first inner ring segment, the first middle ring segment II, and the first outer ring segment II. The second group of flowmeter placement points is selected. The second projected chord length formed by the lines connecting the corresponding two points on the cross section passes only through the middle and outer rings. The second projected chord length is divided into 3 segments: the second outer ring segment I, the second middle ring segment, and the second outer ring segment II. The third group of flowmeter placement points is selected. The projected chord length formed by the lines connecting the corresponding two points on the cross section passes only through the middle and outer rings. The third projected chord length formed by the lines connecting the corresponding two points on the cross section passes only through the middle and outer rings. The third projected chord length is divided into 3 segments: the third outer ring segment I, the third middle ring segment, and the third outer ring segment II. The first projected chord length is perpendicular to the second and third projected chord lengths, respectively. In S3, the total length of the line segments corresponding to the inner ring is the first inner ring line segment; the total length of the line segments corresponding to the middle ring is the sum of the first middle ring line segment I, the first middle ring line segment II, the second middle ring line segment, and the third middle ring line segment; the total length of the line segments corresponding to the outer ring is the sum of the first outer ring line segment I, the first outer ring line segment II, the second outer ring line segment I, the second outer ring line segment II, the third outer ring line segment I, and the third outer ring line segment II. The total lengths of the line segments corresponding to the inner ring, the middle ring, and the outer ring are weighted to obtain the weighted lengths of the inner ring, the middle ring, and the outer ring. It is determined whether the three weighted lengths meet the preset threshold conditions. If they do, three sets of flow meter placement points are output; otherwise, the flow meter placement points are reselected until the preset threshold conditions are met. The weighted formulas for the total lengths of the line segments corresponding to the inner ring, the middle ring, and the outer ring are as follows: Inner ring weighted length = first inner ring segment × first weight coefficient; The weighted length of the middle ring is calculated as follows: First middle ring segment I × First weight coefficient + First middle ring segment II × First weight coefficient + Second middle ring segment × Second weight coefficient + Third middle ring segment × Third weight coefficient. The weighted length of the outer ring is calculated as follows: First outer ring segment I × First weight coefficient + First outer ring segment II × First weight coefficient; Second outer ring segment I × Second weight coefficient + Second outer ring segment II × Second weight coefficient + Third outer ring segment I × Third weight coefficient + Third outer ring segment × Third weight coefficient.

2. The method for arranging multi-channel ultrasonic flow meters for circular chimneys according to claim 1, characterized in that, The preset threshold condition is: In the three weighted lengths, the absolute value of the deviation between any two weighted lengths does not exceed 10%.

3. The method for arranging multi-channel ultrasonic flow meters for circular chimneys according to claim 1, characterized in that, The multi-channel ultrasonic flow meter is arranged according to the three sets of flow meter placement points output; wherein, the multi-channel ultrasonic flow meter includes a transmitting end and a receiving end; the three transmitting ends are arranged on the same cross section located upstream of the chimney, and the three receiving ends are arranged on the same cross section located downstream of the chimney.

4. The method for arranging multi-channel ultrasonic flow meters for circular chimneys according to claim 1, characterized in that, in, The first weighting coefficient corresponding to the first projection chord length is 0.428; the second weighting coefficient and the third weighting coefficient corresponding to the second projection chord length and the third projection chord length are both 0.

286.

5. A method for arranging multi-channel ultrasonic flow meters for a circular chimney according to claim 4, characterized in that, When the first projected chord length is equal to the chimney diameter D, and the second and third projected chord lengths are all equal to 0.66D, the inner ring weighted length, the middle ring weighted length, and the outer ring weighted length are 0.577D, 0.879D, and 0.864D, respectively.

6. A multi-channel ultrasonic flow meter arrangement system for a circular chimney, used to implement the steps of the multi-channel ultrasonic flow meter arrangement method for a circular chimney as described in any one of claims 1-5, characterized in that, include: The cross-section segmentation module is used to obtain any cross-section of a circular chimney and divide the cross-section into multiple equal-area rings based on the equal-ring area method. The point selection module is used to select multiple sets of flow meter placement points on the inner wall of the chimney. The lines connecting each set of placement points form a corresponding projected chord length on the cross section. The projected chord length is divided into several line segments by each ring. The calculation and judgment module is used to perform weighted processing on the total length of the line segment corresponding to each ring to obtain the corresponding weighted total length. It outputs multiple sets of flow meter placement points corresponding to the condition that the weighted total length meets the preset threshold, so as to complete the placement of multi-channel ultrasonic flow meters.

7. A device, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the method for arranging a multi-channel ultrasonic flow meter for a circular chimney as described in any one of claims 1-5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it is used to implement the steps of the method for arranging multi-channel ultrasonic flow meters for a circular chimney as described in any one of claims 1-5.

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