Method and system for determining fine tuning coefficient of ultrasonic gas flowmeter
阅读说明：本技术 一种确定超声波燃气流量计微调系数的方法及系统 (Method and system for determining fine tuning coefficient of ultrasonic gas flowmeter ) 是由 刘勋 李中华 陈伟明 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种确定超声波燃气流量计微调系数的方法及系统,在标定环境下获得超声波燃气流量计的温度流量标定格；使用超声波燃气流量计实际流量计量,获取当前温度和超声波燃气流量计的输出流量；基于输出流量和当前温度在温度流量标定格中确定微调系数。将环境温度和计量的燃气流量同时作为微调系数的标定依据,再结合实际流量计量结果计算出微调系数,该微调系数精准补偿了当前温度对实际流量计量结果室外影响,在微调系数的修正下,能够有效避免计量流量值的偏移现象。(The invention discloses a method and a system for determining a fine tuning coefficient of an ultrasonic gas flowmeter, wherein a temperature flow calibration frame of the ultrasonic gas flowmeter is obtained in a calibration environment; measuring the actual flow of the ultrasonic gas flowmeter to obtain the current temperature and the output flow of the ultrasonic gas flowmeter; a trim factor is determined in a temperature flow calibration grid based on the output flow and the current temperature. The environment temperature and the measured gas flow are simultaneously used as calibration basis of the fine tuning coefficient, and the fine tuning coefficient is calculated by combining the actual flow measurement result, the fine tuning coefficient accurately compensates the outdoor influence of the current temperature on the actual flow measurement result, and the deviation phenomenon of the measured flow value can be effectively avoided under the correction of the fine tuning coefficient.)
1. A method of determining a tuning coefficient for an ultrasonic gas flowmeter, comprising the steps of:
s1, obtaining a temperature and flow rate calibration frame of the ultrasonic gas flowmeter in a calibration environment;
s2, measuring the actual flow by using the ultrasonic gas flowmeter, and acquiring the current temperature and the output flow of the ultrasonic gas flowmeter;
s3, determining a trim factor in the temperature flow calibration grid based on the output flow obtained at S2 and the current temperature.
2. The method of determining a tuning coefficient for an ultrasonic gas flowmeter of claim 1, wherein step S1 comprises the substeps of:
s11, drawing a basic grid by taking the temperature as a horizontal line and the flow as a vertical line, or by taking the flow as a horizontal line and the temperature as a vertical line;
s12, calculating the average speed of the fuel gas in the pipeline based on the flow corresponding to the basic grid intersection point;
s13, calculating a calibration coefficient M of the point according to the calibration coefficient model based on the average speed of the fuel gas in the pipeline;
and S14, recording calibration coefficients of all the intersection points.
3. The method of determining the tuning coefficients of an ultrasonic gas flowmeter of claim 2, wherein the calibration coefficient model is:
in the formula tupTime of flight, t, for ultrasonic wavesdownThe lower flight time of the ultrasonic wave;
Vmis the average velocity of the gas in the pipeline;is the channel angle, L is the channel length; m is a calibration coefficient; k is the fine tuning coefficient.
4. The method of determining a trim factor for an ultrasonic gas meter of claim 2, wherein the base grid has a temperature range of: -30 ℃ to 55 ℃.
5. A method of determining a trim factor for an ultrasonic gas meter according to claim 1, wherein the temperature difference across each square is at least 5 ℃.
6. The method of determining a trim factor for an ultrasonic gas meter of claim 2, wherein the base grid has a flow range of: 0.016m3/h—6m3/h。
7. A method of determining a trim factor for an ultrasonic gas meter according to claim 6, wherein the difference in flow between the two sides of each square is at least 0.222m3/h。
8. The method of determining a tuning coefficient for an ultrasonic gas flowmeter of claim 2, wherein step S3 comprises:
searching a corresponding intersection point in a temperature flow calibration frame according to the output flow and the current temperature, and calibrating by taking a calibration coefficient of the intersection point as a fine adjustment coefficient;
when there is no intersection in the temperature flow calibration grid that coincides with the output flow and the current temperature, the trim coefficients are determined using linear interpolation.
9. The method of determining a trim factor for an ultrasonic gas meter of claim 8,
when a transverse line or a vertical line consistent with the output flow exists in the temperature flow calibration grid, two cross points closest to the current temperature under the output flow are found, and a fine adjustment coefficient is calculated through linear interpolation by combining the cross points and the calibration coefficients corresponding to the cross points;
when a transverse line or a vertical line consistent with the current temperature exists in the temperature flow calibration frame, two cross points closest to the output flow at the current temperature are found, and a fine adjustment coefficient is calculated by linear interpolation by combining the cross points and the corresponding calibration coefficients of the cross points;
when no horizontal line or vertical line consistent with the output flow exists in the temperature flow calibration grid, and no horizontal line or vertical line consistent with the current temperature exists, a grid A where the output flow and the current temperature are located is found, and bilinear interpolation is carried out by combining 4 combination cross points on the grid A and calibration coefficients corresponding to the cross points to calculate fine adjustment coefficients.
10. The system for determining the tuning coefficient of an ultrasonic gas flowmeter according to claim 1, applied to any one of the methods for determining the tuning coefficient of an ultrasonic gas flowmeter in the principle claims 1-9, comprising: the system comprises a temperature and flow calibration module, an actual metering module and a calculation module;
the temperature and flow calibration module obtains a temperature and flow calibration frame of the ultrasonic gas flowmeter in a calibration environment;
the actual metering module is used for metering the actual flow based on the ultrasonic gas flowmeter and acquiring the output quantity and the current temperature of the ultrasonic gas flowmeter;
the calculation module determines a trim factor in a temperature flow calibration frame based on the output quantity and the current temperature.
Technical Field
The invention relates to the technical field of ultrasonic gas metering, in particular to a method and a system for determining a fine tuning coefficient of an ultrasonic gas flowmeter.
Background
Natural gas becomes the first choice of domestic energy structures as a clean, efficient and high-quality energy. With the wide use of natural gas, how to realize fair measurement is particularly important as a gas meter used for urban natural gas consumer trade measurement. Along with the construction and popularization of gas transmission pipelines, gas meters emerge like bamboo shoots in spring after rain, from mechanical type to electronic type, from traditional membrane meters to full-electronic ultrasonic gas meters, new concepts and new technologies continue to emerge, the accuracy and the application range of various flow meters are also continuously improved, and the ultrasonic flow meters gradually move from the industrial field to the household field due to the advantages of advanced technology and easy intellectualization.
In particular, in recent years, ultrasonic gas meters are emerging at a brand-new corner in the gas meter market with strong potential, but the ultrasonic gas meters are all-electronic meters, and the measured flow value can deviate along with the change of the use environment temperature, so that the flow value is larger than the actual flow, and normal measurement cannot be performed; the metering precision of the ultrasonic gas meter is greatly influenced by the flow field, and the requirement on the stability of the flow field is extremely high;
when the deviation between the measured flow value and the actual flow value is large, the phenomenon of exceeding the standard of the flow is easy to occur, and the structural design and installation of the flow channel are required to be carried out again when the flow exceeds the standard, so that larger unnecessary loss is brought.
Disclosure of Invention
The invention aims to solve the technical problems that the ultrasonic gas meter has deviation of a metering value along with the change of temperature, has larger entrance and exit with the actual flow and cannot meter normally; the method and the system have the advantages that the influence of a flow field is large, the requirement on the stability of the flow field is extremely high, and the purpose of the invention is to provide the method and the system for determining the fine adjustment coefficient of the ultrasonic gas flowmeter so as to solve the technical problems.
The invention is realized by the following technical scheme:
the scheme provides a method for determining a fine tuning coefficient of an ultrasonic gas flowmeter, which comprises the following steps:
s1, obtaining a temperature and flow rate calibration frame of the ultrasonic gas flowmeter in a calibration environment;
s2, measuring the actual flow by using the ultrasonic gas flowmeter, and acquiring the current temperature and the output flow of the ultrasonic gas flowmeter;
s3, determining a trim factor in the temperature flow calibration grid based on the output flow obtained at S2 and the current temperature.
The working principle of the scheme is as follows: the ultrasonic gas meter is a full-electronic meter, and the measured flow value can deviate along with the change of the use environment temperature, is larger in or out of the actual flow and cannot be normally measured; the metering precision of the ultrasonic gas meter is greatly influenced by the flow field, and the requirement on the stability of the flow field is extremely high; when the deviation between the measured flow value and the actual flow value is large, the phenomenon of exceeding the standard of the flow is easy to occur, and the structural design and installation of the flow channel are required to be carried out again when the flow exceeds the standard, so that larger unnecessary loss is brought. According to the method for finely adjusting the coefficient of the ultrasonic gas flowmeter, the ambient temperature and the measured gas flow are simultaneously used as calibration bases of the fine adjustment coefficient, the fine adjustment coefficient is calculated by combining the actual flow measurement result, the fine adjustment coefficient accurately compensates the outdoor influence of the current temperature on the actual flow measurement result, and the deviation phenomenon of the measured flow value can be effectively avoided under the correction of the fine adjustment coefficient.
Further optimization scheme is that step S1 includes the following sub-steps:
s11, drawing a basic grid by taking the temperature as a horizontal line and the flow as a vertical line, or by taking the flow as a horizontal line and the temperature as a vertical line;
s12, calculating the average speed of the fuel gas in the pipeline based on the flow corresponding to the basic grid intersection point;
s13, calculating a calibration coefficient M of the point according to the calibration coefficient model based on the average speed of the fuel gas in the pipeline;
and S14, recording calibration coefficients of all the intersection points.
The further optimization scheme is that the calibration coefficient model is as follows:
in the formula tupTime of flight, t, for ultrasonic wavesdownThe lower flight time of the ultrasonic wave;
Vmis the average velocity of the gas in the pipeline;is the channel angle, L is the channel length; and M is a calibration coefficient.
The further optimization scheme is that the temperature range of the basic grids is as follows: -30 ℃ to 55 ℃.
In a further preferred embodiment, the temperature difference across each square is at least 5 ℃.
The further optimization scheme is that the flow range of the basic grid is as follows: 0.016m3/h—6m3/h。
The further optimization scheme is that the flow difference between two edges of each square grid is at least 0.222m3/h。
In a calibration environment, the basic squares traverse all the temperatures and the flow rates of the gas pipeline, the temperature difference between two sides of each square is at least 5 ℃, and the flow rate difference is at least 0.222m3And h, the larger the temperature difference or the flow difference is, the denser the basic grids are, the more the corresponding calibration coefficients are, but the larger the occupied memory space is, and the longer the calculation time is.
Further optimization, step S3 includes:
searching a corresponding intersection point in a temperature flow calibration frame according to the output flow and the current temperature, and calibrating by taking a calibration coefficient of the intersection point as a fine adjustment coefficient;
when there is no intersection in the temperature flow calibration grid that coincides with the output flow and the current temperature, the trim coefficients are determined using linear interpolation.
The further optimization scheme is that when a transverse line or a vertical line consistent with the output flow exists in the temperature flow calibration grid, two cross points closest to the current temperature under the output flow are found, and the cross points and calibration coefficients corresponding to the cross points are combined to calculate fine adjustment coefficients through linear interpolation;
when a transverse line or a vertical line consistent with the current temperature exists in the temperature flow calibration frame, two cross points closest to the output flow at the current temperature are found, and a fine adjustment coefficient is calculated by linear interpolation by combining the cross points and the corresponding calibration coefficients of the cross points;
when no horizontal line or vertical line consistent with the output flow exists in the temperature flow calibration grid, and no horizontal line or vertical line consistent with the current temperature exists, a grid A where the output flow and the current temperature are located is found, and bilinear interpolation is carried out by combining 4 combination cross points on the grid A and calibration coefficients corresponding to the cross points to calculate fine adjustment coefficients.
In consideration of occupied memory space, the method and the device calculate points which are not in the temperature and flow calibration grid by using a linear interpolation method, and have targeted calculation so as to avoid unnecessary calculation of the temperature and flow calibration grid.
The linear interpolation method is used for calculating to obtain the numerical value which is not included in the table look-up process, the interpolation method is simple, the interpolation error on each interpolation node is 0, and the scheme further improves the calculation precision through the gradual approximation of the linear interpolation method for multiple times.
This scheme still a system of confirming ultrasonic wave gas flowmeter fine setting coefficient, is applied to above-mentioned method of confirming ultrasonic wave gas flowmeter fine setting coefficient, includes: the system comprises a temperature and flow calibration module, an actual metering module and a calculation module;
the temperature and flow calibration module obtains a temperature and flow calibration frame of the ultrasonic gas flowmeter in a calibration environment;
the actual metering module is used for metering the actual flow based on the ultrasonic gas flowmeter and acquiring the output quantity and the current temperature of the ultrasonic gas flowmeter;
the calculation module determines a trim factor in a temperature flow calibration frame based on the output quantity and the current temperature.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. the method for determining the fine tuning coefficient of the ultrasonic gas flowmeter provided by the invention simultaneously uses the ambient temperature and the measured gas flow as the calibration basis of the fine tuning coefficient, and then calculates the fine tuning coefficient by combining the actual flow measurement result, the fine tuning coefficient accurately compensates the outdoor influence of the current temperature on the actual flow measurement result, and the deviation phenomenon of the measured flow value can be effectively avoided under the correction of the fine tuning coefficient;
2. the method and the system for determining the fine tuning coefficient of the ultrasonic gas flowmeter calculate and obtain the numerical value which is not available in the table look-up process by using the linear interpolation method, the interpolation method is simple, the interpolation error on each interpolation node is 0, the precision of the fine tuning coefficient is further improved by gradually approaching through the linear interpolation method and the bilinear interpolation method, and the finally output metering value is closer to the actual value.
Drawings
In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and that for those skilled in the art, other related drawings can be obtained from these drawings without inventive effort. In the drawings:
FIG. 1 is a schematic flow diagram of a method for determining a tuning coefficient for an ultrasonic gas flow meter;
FIG. 2 is a schematic diagram of linear interpolation for output flow consistency of example 1;
FIG. 3 is a schematic diagram of linear interpolation for current temperature uniformity in example 1;
fig. 4 is a schematic diagram of bilinear interpolation in which the output flow rate and the current temperature are inconsistent in embodiment 1.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
As shown in fig. 1, a method of determining a trim factor for an ultrasonic gas meter, comprising the steps of:
s1, obtaining a temperature and flow rate calibration frame of the ultrasonic gas flowmeter in a calibration environment;
s2, measuring the actual flow by using the ultrasonic gas flowmeter, and acquiring the current temperature and the output flow of the ultrasonic gas flowmeter;
s3, determining a trim factor in the temperature flow calibration grid based on the output flow obtained at S2 and the current temperature.
Step S1 includes the following substeps:
s11, drawing a basic grid by taking the temperature as a horizontal line and the flow as a vertical line, or by taking the flow as a horizontal line and the temperature as a vertical line;
s12, calculating the average speed of the fuel gas in the pipeline based on the flow corresponding to the basic grid intersection point;
s13, calculating a calibration coefficient M of the point according to the calibration coefficient model based on the average speed of the fuel gas in the pipeline;
and S14, recording calibration coefficients of all the intersection points.
The calibration coefficient model is as follows:
in the formula tupTime of flight, t, for ultrasonic wavesdownThe lower flight time of the ultrasonic wave;
Vmis the average velocity of the gas in the pipeline;is the channel angle, L is the channel length; and M is a calibration coefficient.
The temperature range of the basic grids is as follows: -30 ℃ to 55 ℃.
The temperature difference across each square is at least 5 ℃.
The flow range of the basic grid is as follows: 0.016m3/h—6m3/h。
The flow difference between two sides of each square is at least 0.222m3/h。
Step S3 includes:
searching a corresponding intersection point in a temperature flow calibration frame according to the output flow and the current temperature, and calibrating by taking a calibration coefficient of the intersection point as a fine adjustment coefficient;
when there is no intersection in the temperature flow calibration grid that coincides with the output flow and the current temperature, the trim coefficients are determined using linear interpolation.
As shown in fig. 2, when there is a horizontal line or a vertical line in the temperature flow calibration grid consistent with the output flow, two intersections closest to the current temperature under the output flow are found, and a linear interpolation is performed to calculate a fine adjustment coefficient by combining the intersections and the calibration coefficients corresponding to the intersections;
current temperature E obtained by actual flow measurement of ultrasonic gas flowmeterTAnd output flow EVWhen V2 is at point E, the output flow rate falls on the horizontal line of the temperature flow rate scale frame V2, and the current temperature ETBetween T1 and T2, find the two junctions E1 and E2 with the output flow at V2 closest to the current temperature;
the known intersection point E1 (temperature T1, flow V2, calibration factor M)E1) Cross-over point E2 (temperature T2, flow V2, calibration factor M)E2) Point E (current temperature E)TOutput flow EVV2), and performing linear interpolation between the intersection E1 and the intersection E2 to calculate a calibration coefficient of the point E, that is, a fine adjustment coefficient of the point E.
As shown in fig. 3, when there is a horizontal line or a vertical line in the temperature-flow calibration grid that is consistent with the current temperature, two intersections closest to the output flow at the current temperature are found, and a linear interpolation is performed to calculate a fine adjustment coefficient by combining the intersections and the calibration coefficients corresponding to the intersections;
current temperature G obtained by actual flow measurement of ultrasonic gas flowmeterTT1 and output flow GVFalls on the point G, the current temperature of which falls on the vertical line of the temperature and flow rate calibration frame T1, and the output flow rate GVBetween V1 and V2, find the two intersections G1 and G2 where the current temperature is closest to the output flow at T1;
the known intersection G1 (temperature T1, flow V1, calibration factor M)G1) Cross-over point G2 (temperature T1, flow V2, calibration factor M)G2) Point G (current temperature G)TOutput flow G ═ T1V) And performing linear interpolation between the intersection G1 and the intersection G2 to calculate the calibration coefficient of the G point, namely the fine tuning coefficient of the G point.
As shown in fig. 4, when there is no horizontal line or vertical line in the temperature flow calibration grid that is consistent with the output flow, or there is no horizontal line or vertical line that is consistent with the current temperature, find the grid a where the output flow and the current temperature are located, and calculate the fine adjustment coefficient by bilinear interpolation in combination with the calibration coefficients corresponding to the 4 junction points and the junction points on the grid a.
Current temperature O obtained by actual flow measurement of ultrasonic gas flowmeterTAnd output flow OVFalling on the point O, the current temperature and the output flow of which fall on the ABDC grids of the temperature flow calibration grid;
the known intersection A (temperature T1, flow V1, calibration factor M)A) Cross-over point B (temperature T2, flow V1, calibration factor M)B) Cross-over C (temperature T1, flow V2, calibration factor M)C) Cross-over point D (temperature T2, flow V2, calibration factor M)D) Point O (current temperature O)TOutput flow rate OV)；
According to bilinear interpolation, firstly, two values of R1 and R2 are interpolated in the flow horizontal line direction (or the interpolation can be started in the temperature vertical line direction), and then the calibration coefficient of the O point, namely the fine adjustment coefficient of the G point, is calculated by interpolating the O point according to R1 and R2.
Example 2
The system for determining the fine tuning coefficient of the ultrasonic gas flowmeter is applied to the method for determining the fine tuning coefficient of the ultrasonic gas flowmeter in the previous embodiment, and comprises the following steps: the system comprises a temperature and flow calibration module, an actual metering module and a calculation module;
the temperature and flow calibration module obtains a temperature and flow calibration frame of the ultrasonic gas flowmeter in a calibration environment;
the actual metering module is used for metering the actual flow based on the ultrasonic gas flowmeter and acquiring the output quantity and the current temperature of the ultrasonic gas flowmeter;
the calculation module determines a trim factor in a temperature flow calibration frame based on the output quantity and the current temperature.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.