CN-117589251-B - Multi-channel ultrasonic flowmeter arrangement method for circular chimney and related equipment

CN117589251BCN 117589251 BCN117589251 BCN 117589251BCN-117589251-B

Abstract

The invention discloses a multichannel ultrasonic flowmeter arrangement method and related equipment for a circular chimney, which belong to the technical field of gas flow monitoring, wherein the method is based on the multichannel arrangement concept, a circular section is divided into a plurality of rings with equal area, a plurality of groups of flowmeter arrangement points are selected on the inner wall of the chimney, a corresponding projection chord length is formed on the section by connecting lines among the arrangement points, the projection chord length is divided into a plurality of line segments by each ring, the total length of the line segments is weighted, and finally, the corresponding flowmeter arrangement points are output through judgment that the weighted length meets the preset threshold condition so as to finish multichannel ultrasonic flowmeter arrangement; the method can ensure the accuracy of flue gas flow measurement aiming at the circular chimney, has the design principle similar to the principle of the area method such as the non-uniform flow field, and has the obvious advantages of accurate measurement, strong adaptability to the non-uniform flow field and the like.

Inventors

CAI CHUN
XIE HUANBIAO
CHEN MINGGUANG
CHEN YUZHONG
WANG HUI
JIANG XINGGUO
ZHONG DI
FENG TINGYOU
LI LINGSHAN
Lin Wucun
WANG ZIHAN
CHEN PEIFENG

Assignees

华能汕头海门发电有限责任公司
中国华能集团清洁能源技术研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20231122

Claims (8)

1. A method of multi-channel ultrasonic flow meter placement for a circular chimney, comprising: S1, acquiring any section of a circular chimney, and dividing the section into a plurality of equal-area circular rings based on an equal-area method; S2, selecting a plurality of groups of flowmeter arrangement points on the inner wall of the chimney, wherein the connecting lines among the arrangement points form corresponding projection chord lengths on the section, and the projection chord lengths are divided into a plurality of line segments by each circular ring; S3, carrying out weighting treatment on the total length of the line segment corresponding to each ring to obtain a corresponding weighted total length, and outputting a plurality of groups of flowmeter arrangement points corresponding to the weighted total length meeting the preset threshold value condition so as to finish multichannel ultrasonic flowmeter arrangement; The specific steps are as follows: S1, dividing a section into 3 equal-area circular rings of an inner ring, a middle ring and an outer ring based on an equal-area circular method; s2, selecting a first group of flowmeter arrangement points, wherein a first projection chord length formed on the section corresponding to the two-point connecting line passes through all the circular rings, and the first projection chord length is divided into 5 line segments which are a first outer ring line segment I, a first middle ring line segment I, a first inner ring line segment, a first middle ring line segment II and a first outer ring line segment II respectively; selecting a second group of flowmeter arrangement points, wherein a second projection chord length formed on the section corresponding to the two-point connecting line only passes through the middle ring and the outer ring, and the second projection chord length is divided into 3 line segments which are respectively a second outer ring line segment I, a second middle ring line segment and a second outer ring line segment II; the third projection chord length formed by connecting the two points on the section only passes through the middle ring and the outer ring, and is divided into 3 line segments which are respectively a third outer ring line segment I, a third middle ring line segment and a third outer ring line segment II; the total length of the line segments corresponding to the inner ring is a 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 length of the line segments corresponding to the inner ring, the total length of the line segments corresponding to the middle ring and the total length of the line segments corresponding to the outer ring are weighted to obtain an inner ring weighted length, a middle ring weighted length and an outer ring weighted length, and whether 3 weighted lengths meet preset threshold conditions is judged, if yes, 3 groups of flowmeter arrangement points are output, otherwise, the flowmeter arrangement points are reselected until the preset threshold conditions are met; the total length of the line segment corresponding to the inner ring, the total length of the line segment corresponding to the middle ring and the total length of the line segment corresponding to the outer ring are weighted according to the following processing formula: inner loop weighted length = first inner loop segment x first weight coefficient; Middle ring weighted length=first middle ring line segment i×first weight coefficient+first middle ring line segment ii×first weight coefficient+second middle ring line segment×second weight coefficient+third middle ring line segment×third weight coefficient; Outer loop weighted length = first outer loop segment I x first weight coefficient + first outer loop segment II x first weight coefficient second outer loop segment I x second weight coefficient + second outer loop segment II x second weight coefficient + third outer loop segment I x third weight coefficient + third outer loop segment x third weight coefficient.
2. The method of arranging a multi-channel ultrasonic flow meter for a circular chimney according to claim 1, wherein the preset threshold condition is: the absolute value of the deviation between every 2 weighted lengths in the 3 groups of weighted lengths is not more than 10 percent.
3. The method for arranging a multi-channel ultrasonic flowmeter for a circular chimney according to claim 1, wherein the multi-channel ultrasonic flowmeter is arranged according to 3 groups of output flowmeter arranging points, wherein the multi-channel ultrasonic flowmeter comprises a transmitting end and a receiving end, 3 transmitting ends are arranged on the same section positioned at the upstream of the chimney, and 3 receiving ends are arranged on the same section positioned at the downstream of the chimney.
4. The method of claim 1, wherein the first weight coefficient corresponding to the first projected chord length is 0.428, and the second weight coefficient and the third weight coefficient corresponding to the second projected chord length and the third projected chord length are both 0.286.
5. The method of claim 4, wherein the inner loop weighted length, the middle loop weighted length, and the outer loop weighted length are 0.577D, 0.879D, and 0.864D, respectively, when the first projected chord length is equal to the chimney diameter D, the second projected chord length, and the third projected chord length are each equal to 0.66D.
6. A multi-channel ultrasonic flow meter arrangement system for a circular chimney, for implementing the steps of the multi-channel ultrasonic flow meter arrangement method for a circular chimney of any of claims 1-5, comprising: The section dividing module is used for acquiring any section of the circular chimney and dividing the section into a plurality of equal-area circular rings based on an equal-area method; The point position selecting module is used for selecting a plurality of groups of flowmeter arrangement points on the inner wall of the chimney, wherein the connecting lines among the arrangement points form corresponding projection chord lengths on the section, and the projection chord lengths are divided into a plurality of line segments by each circular ring; the calculation judging module is used for carrying out weighting processing on the total length of the line segment corresponding to each ring to obtain the corresponding weighted total length, and outputting a plurality of groups of flowmeter arrangement points corresponding to the weighted total length meeting the preset threshold condition so as to finish the arrangement of the multichannel ultrasonic flowmeter.
7. An apparatus, comprising: A memory for storing a computer program; A processor for implementing the steps of the multi-channel ultrasonic flow meter arrangement method for a circular chimney of any of claims 1-5 when executing said computer program.
8. A computer readable storage medium storing a computer program, characterized in that the computer program is executed by a processor for implementing the steps of the multi-channel ultrasonic flow meter arrangement method for a circular chimney according to any of claims 1-5.

Description

Multi-channel ultrasonic flowmeter arrangement method for circular chimney and related equipment Technical Field The invention belongs to the technical field of gas flow monitoring, and particularly relates to a multichannel ultrasonic flowmeter arrangement method for a circular chimney and related equipment. Background Along with the rapid development of economy, the requirements of various industrial fields on the accurate measurement of the smoke emission of a chimney are increasingly urgent, so that the aims of further realizing energy conservation, safe production, pollution control and the like are fulfilled. In order to meet the requirement of continuously improving the accuracy of gas flow measurement, ultrasonic technology is applied to gas flow detection. For flow rate measurements in a circular chimney, it is common practice in engineering to arrange a pair of ultrasonic transducers in the diameter direction, with the receiving end arranged downstream of the emitting end. For a chimney with a circular section, the phenomenon of uneven flue gas flow velocity distribution is common, and the flow velocity of the center of a common chimney is high and the flow velocity close to the pipe wall is low due to the flow law in the circular pipe, if only a single-channel ultrasonic gas flowmeter is adopted to measure the linear velocity average value along the diameter direction, the average flue gas flow velocity of the whole section cannot be represented. Currently, for measuring the average flow velocity of a non-uniform flow field with a circular cross section, the preferred method is to divide the rings according to an equal area method, then measure the flow velocity respectively for each ring, and the average value of the flow velocity of each ring is the average flow velocity of the whole cross section. According to the measurement principle, if the linear average speed is measured along the diameter direction, when the flow rate of the center of the chimney is higher, the measurement value of the conventional ultrasonic gas flowmeter is larger, the measurement deviation is required to be reduced by on-site verification, namely, correction is performed by adopting a verification coefficient, but under different flow rates, the higher flow rate of the center of the chimney is inconsistent and is difficult to correct by adopting a fixed verification coefficient, so that the measurement accuracy of the flow in the heterogeneous flow field of the circular chimney cannot be ensured by adopting the measurement mode. Disclosure of Invention In order to overcome the defects of the technology, the invention provides a multichannel ultrasonic flowmeter arrangement method for a circular chimney and related equipment. In order to achieve the above purpose, the present invention adopts the following technical contents: A multi-channel ultrasonic flow meter arrangement method for a circular chimney, comprising: S1, acquiring any section of a circular chimney, and dividing the section into a plurality of equal-area circular rings based on an equal-area method; S2, selecting a plurality of groups of flowmeter arrangement points on the inner wall of the chimney, wherein the connecting lines among the arrangement points form corresponding projection chord lengths on the section, and the projection chord lengths are divided into a plurality of line segments by each circular ring; and S3, carrying out weighting processing on the total length of the line segment corresponding to each ring to obtain a corresponding weighted total length, and outputting a plurality of groups of flowmeter arrangement points corresponding to the weighted total length meeting the preset threshold value condition so as to finish multichannel ultrasonic flowmeter arrangement. Further, the specific steps are as follows: S1, dividing a section into 3 equal-area circular rings of an inner ring, a middle ring and an outer ring based on an equal-area circular method; s2, selecting a first group of flowmeter arrangement points, wherein a first projection chord length formed on the section corresponding to the two-point connecting line passes through all the circular rings, and the first projection chord length is divided into 5 line segments which are a first outer ring line segment I, a first middle ring line segment I, a first inner ring line segment, a first middle ring line segment II and a first outer ring line segment II respectively; selecting a second group of flowmeter arrangement points, wherein a second projection chord length formed on the section corresponding to the two-point connecting line only passes through the middle ring and the outer ring, and the second projection chord length is divided into 3 line segments which are respectively a second outer ring line segment I, a second middle ring line segment and a second outer ring line segment II; the third projection chord length formed by connecting the two points on the section only