CN114459554B - Method for improving instantaneous flow metering precision of ultrasonic gas meter based on pressure data - Google Patents

Method for improving instantaneous flow metering precision of ultrasonic gas meter based on pressure data Download PDF

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CN114459554B
CN114459554B CN202210372274.8A CN202210372274A CN114459554B CN 114459554 B CN114459554 B CN 114459554B CN 202210372274 A CN202210372274 A CN 202210372274A CN 114459554 B CN114459554 B CN 114459554B
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flow
ultrasonic
propagation time
pressure difference
gas
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CN114459554A (en
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石爱国
宋莎莎
张金龙
徐伟
王颖嘉
杨庆珍
李腾
康惠海
曹国荣
管利军
蒋宇航
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Hangzhou Innover Technology Co ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
    • G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
    • G01F15/02—Compensating or correcting for variations in pressure, density or temperature
    • G01F15/04—Compensating or correcting for variations in pressure, density or temperature of gases to be measured

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  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Volume Flow (AREA)
  • Electromagnetism (AREA)

Abstract

The invention relates to a method for improving the instantaneous flow metering precision of an ultrasonic gas meter based on pressure data. The method is characterized in that: installing a differential pressure sensor in the ultrasonic gas meter, wherein two gas pressure acquisition ports of the differential pressure sensor are respectively installed in a flow channel and outside the flow channel, so that the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter is detected, the downstream propagation time and the upstream propagation time of the ultrasonic wave in the gas at the current moment are measured by adopting a time difference method, and the instantaneous flow is calculated by utilizing the downstream propagation time and the upstream propagation time of the ultrasonic wave in a gas medium; and judging whether the wave jump problem exists or not according to the measured pressure difference and the instantaneous flow, and correcting the downstream propagation time and the upstream propagation time at the current moment by using pressure difference data when the wave jump phenomenon occurs, so that the accurate instantaneous flow at the current moment is obtained, and the metering precision of the instantaneous flow of the ultrasonic gas meter is improved.

Description

Method for improving instantaneous flow measurement precision of ultrasonic gas meter based on pressure data
Technical Field
The invention relates to a method for improving the instantaneous flow metering precision of an ultrasonic gas meter based on pressure data.
Background
The ultrasonic gas meter has the advantages of non-contact measurement, no movable part, no pressure loss, extremely high measurement precision and the like, and is a research hotspot in the field of gas measurement. An ultrasonic gas meter widely used in the market is generally based on a time difference method, and instantaneous flow is estimated by measuring forward flow propagation time and backward flow propagation time of ultrasonic waves in a gas medium, so that the forward flow propagation time and the backward flow propagation time of the ultrasonic waves in the gas medium are key measurement values of instantaneous flow measurement of the ultrasonic gas meter, and the measurement precision is directly influenced. In the existing scheme, a threshold value method is adopted to detect the propagation time of an ultrasonic signal in a gas medium, but the amplitude change or deformation of the received ultrasonic signal can be caused by the change of the working temperature of an ultrasonic gas meter, the instability of a gas flow field or the change of gas components, so that the threshold value is easily triggered on different rising edges of the ultrasonic signal instead of being always triggered on the same rising edge, and the measured downstream propagation time and the measured upstream propagation time generate time errors of one or more ultrasonic transducer excitation signal periods, namely, a wave jumping phenomenon, thereby causing the calculation of instantaneous flow and larger deviation of an actual value. In the prior art, a plurality of groups of data are collected, and the problem of wave hopping is processed by using a software averaging algorithm, but the method can influence the timeliness and accuracy of metering readings.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a technical scheme of a method for improving the instantaneous flow metering precision of an ultrasonic gas meter based on pressure data.
The method for improving the instantaneous flow metering precision of the ultrasonic gas meter based on the pressure data is characterized by comprising the following steps of: installing a differential pressure sensor in the ultrasonic gas meter, wherein two gas pressure acquisition ports of the differential pressure sensor are respectively installed in a flow channel and outside the flow channel, so that the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter is detected, the downstream propagation time and the upstream propagation time of the ultrasonic wave in the gas at the current moment are measured by adopting a time difference method, and the instantaneous flow is calculated by utilizing the downstream propagation time and the upstream propagation time of the ultrasonic wave in a gas medium; and judging whether the wave jump problem exists according to the measured pressure difference and the instantaneous flow, and correcting the downstream propagation time and the upstream propagation time at the current moment by using pressure difference data when the wave jump phenomenon occurs, so as to obtain the accurate instantaneous flow at the current moment.
The method for improving the instantaneous flow metering precision of the ultrasonic gas meter based on the pressure data is characterized in that the instantaneous flow calculation comprises the following steps:
(1) measuring the relation between the pressure difference and the instantaneous flow, (2) measuring the instantaneous flow by using a time difference method, and (3) judging whether the wave is jumped or not, and adjusting the forward flow propagation time and the reverse flow propagation time of the ultrasonic wave in the gas medium.
The method for improving the instantaneous flow metering precision of the ultrasonic gas meter based on the pressure data is characterized in that the method for measuring the relation between the pressure difference and the instantaneous flow in the step (1) is as follows:
installing a differential pressure sensor in a flow channel of the ultrasonic gas meter, and detecting the pressure difference inside and outside the flow channel of the ultrasonic gas meter through the differential pressure sensor; according to the Bernoulli equation, the pressure inside and outside the flow channel of the ultrasonic gas meter meets the following formula:
Figure 698040DEST_PATH_IMAGE001
（1）
wherein,
Figure 84022DEST_PATH_IMAGE002
is the pressure in the cavity of the ultrasonic gas meter,
Figure 332601DEST_PATH_IMAGE003
is the pressure in the flow channel of the ultrasonic gas meter,
Figure 445919DEST_PATH_IMAGE004
is the average flow velocity of the gas medium in the cavity of the ultrasonic gas meter,
Figure 729133DEST_PATH_IMAGE005
the gas medium in the flow passage of the ultrasonic gas meter is uniform and uniformAt the speed of the operation of the device,
Figure 20437DEST_PATH_IMAGE006
is the gas density;
from conservation of mass, we obtain:
Figure 756312DEST_PATH_IMAGE007
（2）
wherein,
Figure 673321DEST_PATH_IMAGE008
is the sectional area in the cavity of the ultrasonic gas meter,
Figure 811042DEST_PATH_IMAGE009
the cross section area in the flow channel of the ultrasonic gas meter;
the pressure difference between the inside and the outside of the flow passage of the ultrasonic gas meter is obtained by the formulas (1) and (2)
Figure 273247DEST_PATH_IMAGE010
：
Figure 496418DEST_PATH_IMAGE011
（3）
According to the formula (3), the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter measured by the differential pressure sensor is related to the average flow velocity of the gas medium in the flow channel, and the instantaneous flow is the product of the average flow velocity of the gas medium in the flow channel and the cross section area of the flow channel, so that the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter is related to the instantaneous flow of the ultrasonic gas meter;
flow is sequentially introduced to obtain pressure difference data under different instantaneous flows, and a function model is used for carrying out data fitting on the pressure difference data and the instantaneous flows:
Figure 951539DEST_PATH_IMAGE012
wherein, in the process,
Figure 943766DEST_PATH_IMAGE013
which is indicative of a pressure difference between the two,
Figure 842451DEST_PATH_IMAGE014
is indicative of the instantaneous flow rate of the fluid,
Figure 552918DEST_PATH_IMAGE015
is a functional model fitted to the pressure difference and instantaneous flow.
The method for improving the instantaneous flow metering precision of the ultrasonic gas meter based on the pressure data is characterized in that the step (2) of measuring the instantaneous flow by using a time difference method comprises the following steps:
Figure 546151DEST_PATH_IMAGE016
（4）
Figure 658464DEST_PATH_IMAGE017
（5）
in the above formulas (4) and (5),
Figure 462472DEST_PATH_IMAGE018
is the cross section area of the flow passage of the ultrasonic gas meter,
Figure 643923DEST_PATH_IMAGE019
is the average speed of the gas medium in the flow channel of the ultrasonic gas meter,
Figure 191579DEST_PATH_IMAGE020
is the length of the sound path,
Figure 158398DEST_PATH_IMAGE021
is the angle of the sound track,
Figure 398887DEST_PATH_IMAGE022
is the downstream propagation time of the ultrasonic wave in the gas medium,
Figure 67634DEST_PATH_IMAGE023
is the countercurrent propagation time of ultrasonic waves in a gas medium; wherein, the cross-sectional area of the flow passage
Figure 418981DEST_PATH_IMAGE018
Length of sound path
Figure 240307DEST_PATH_IMAGE020
Angle of sound channel
Figure 386117DEST_PATH_IMAGE021
The instantaneous flow can be calculated by the forward flow propagation time and the reverse flow propagation time of the ultrasonic wave in the gas medium
Figure 542161DEST_PATH_IMAGE024
。
The method for improving the instantaneous flow metering precision of the ultrasonic gas meter based on the pressure data is characterized in that the step (3) judges whether the wave is jumped or not, and the steps of adjusting the forward flow propagation time and the reverse flow propagation time of the ultrasonic wave in the gas medium are as follows:
calculating the instantaneous flow at the current moment according to the time difference method measuring principle in the step (2)
Figure 431619DEST_PATH_IMAGE025
Then, the current theoretical pressure difference can be deduced according to the functional relation between the pressure difference and the instantaneous flow obtained in the step (1)
Figure 107451DEST_PATH_IMAGE026
(ii) a Differential pressure sensor for detecting pressure difference inside and outside flow channel of ultrasonic gas meter in real time
Figure 939010DEST_PATH_IMAGE027
When the difference between the measured pressure difference and the theoretical pressure difference is found
Figure 67503DEST_PATH_IMAGE028
，
Figure 26232DEST_PATH_IMAGE029
The maximum range of the allowable difference between the actually measured pressure difference and the theoretical pressure difference indicates that no wave jump phenomenon exists at the moment; when the difference between the measured pressure difference and the theoretical pressure difference
Figure 556570DEST_PATH_IMAGE030
When the instantaneous flow is calculated incorrectly, the ultrasonic waves have the existence of bouncing waves in the time measurement of the downstream propagation time and the upstream propagation time in the gas medium, so that the downstream propagation time and the upstream propagation time of the ultrasonic waves in the gas medium need to be adjusted;
from measured pressure differences
Figure 559030DEST_PATH_IMAGE031
And the functional relation between the pressure difference and the instantaneous flow rate to deduce the theoretical instantaneous flow rate
Figure 440399DEST_PATH_IMAGE032
，
Figure 671660DEST_PATH_IMAGE033
The theoretical forward flow propagation time and the theoretical reverse flow propagation time of the ultrasonic wave in the gas medium approximately satisfy the following relation:
Figure 587663DEST_PATH_IMAGE034
（6）
Figure 495445DEST_PATH_IMAGE035
（7）
in the formulae (6) and (7),
Figure 864110DEST_PATH_IMAGE036
is the theoretical downstream propagation time of the ultrasonic wave in the gas medium,
Figure 899062DEST_PATH_IMAGE037
is the theoretical counter-current propagation time of the ultrasonic wave in the gas medium,
Figure 669572DEST_PATH_IMAGE038
is the propagation velocity of sound waves in a gaseous medium; in addition, when the wave jumping phenomenon occurs, the forward flow propagation time of the ultrasonic wave in the gas medium is actually measured
Figure 764567DEST_PATH_IMAGE039
And the theoretical downstream propagation time of ultrasonic waves in a gas medium
Figure 869795DEST_PATH_IMAGE040
Approximately differing by an integer number of ultrasonic transducer excitation signal periods, and actually measuring the counter-current propagation time of ultrasonic waves in a gas medium
Figure 708438DEST_PATH_IMAGE041
Theoretical counter-current propagation time with ultrasonic wave in gas medium
Figure 67875DEST_PATH_IMAGE042
Approximately differing by an integer number of ultrasonic transducer excitation signal periods, the approximate relationship is as follows:
Figure 333771DEST_PATH_IMAGE043
（8）
Figure 684154DEST_PATH_IMAGE044
（9）
in the formulas (8) and (9),
Figure 592067DEST_PATH_IMAGE045
is the period of the ultrasonic transducer excitation signal,
Figure 806010DEST_PATH_IMAGE046
、
Figure 508387DEST_PATH_IMAGE047
represents the wave number; the passing formula (6) -9 can adjust the actual measurement forward flow propagation time and the actual measurement reverse flow propagation time of the ultrasonic wave in the gas medium, thereby obtaining the instantaneous flow at the current moment
Figure 322628DEST_PATH_IMAGE048
The following formula:
Figure 503074DEST_PATH_IMAGE049
（10） 。
the invention installs a differential pressure sensor in the ultrasonic gas meter, the differential pressure sensor detects the pressure difference inside and outside the flow channel of the ultrasonic gas meter, obtains the data corresponding to the pressure difference and the instantaneous flow, and fits the data, and establishes the functional relation between the pressure difference and the instantaneous flow; when the ultrasonic gas meter is used, the theoretical pressure difference at the current moment is obtained according to the current moment instantaneous flow and the function relation between the pressure difference and the instantaneous flow, and the theoretical pressure difference is compared with the pressure difference actually measured by the differential pressure sensor, so that whether the wave jumping phenomenon exists or not is judged; when the wave jumping phenomenon occurs, the actually measured downstream propagation time and the actually measured upstream propagation time of the ultrasonic wave in the gas medium are corrected by using the pressure difference data, so that the accurate instantaneous flow is obtained, and the metering precision of the instantaneous flow of the ultrasonic gas meter is improved.
Detailed Description
The invention relates to a method for improving the instantaneous flow metering precision of an ultrasonic gas meter based on pressure data, wherein a differential pressure sensor is arranged in a flow passage of the ultrasonic gas meter, the differential pressure sensor is used for detecting the pressure difference between the inside and the outside of the flow passage of the ultrasonic gas meter, obtaining the data corresponding to the pressure difference and the instantaneous flow, and fitting the data to establish the functional relation between the pressure difference and the instantaneous flow; when the ultrasonic gas meter is used, the theoretical pressure difference at the current moment is obtained according to the current moment instantaneous flow and the function relation between the pressure difference and the instantaneous flow, and the theoretical pressure difference is compared with the pressure difference actually measured by the differential pressure sensor, so that whether the wave jumping phenomenon exists or not is judged; when the wave hopping phenomenon occurs, the pressure difference is used for correcting the actually measured forward flow propagation time and the actually measured backward flow propagation time of the ultrasonic wave in the gas medium.
The calculation of the instantaneous flow rate comprises the following steps:
(1) measuring pressure differential versus instantaneous flow
A differential pressure sensor is arranged in a flow channel of the ultrasonic gas meter, and two gas pressure acquisition ports of the differential pressure sensor are respectively arranged in the flow channel and outside the flow channel, so that the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter is detected. According to the Bernoulli equation, the pressure inside and outside the flow channel of the ultrasonic gas meter meets the following formula:
Figure 837103DEST_PATH_IMAGE050
（1）
wherein,
Figure 444802DEST_PATH_IMAGE002
is the pressure in the cavity of the ultrasonic gas meter,
Figure 746339DEST_PATH_IMAGE003
is the pressure in the flow channel of the ultrasonic gas meter,
Figure 464897DEST_PATH_IMAGE004
is the average flow velocity of the gas medium in the cavity of the ultrasonic gas meter,
Figure 184591DEST_PATH_IMAGE005
is the average flow velocity of a gas medium in a flow channel of the ultrasonic gas meter,
Figure 963191DEST_PATH_IMAGE006
is the gas density;
from conservation of mass, we obtain:
Figure 502757DEST_PATH_IMAGE051
（2）
wherein,
Figure 274273DEST_PATH_IMAGE008
is the sectional area in the cavity of the ultrasonic gas meter,
Figure 582894DEST_PATH_IMAGE009
the cross section area in the flow channel of the ultrasonic gas meter;
the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter is obtained by the formulas (1) and (2)
Figure 532396DEST_PATH_IMAGE010
：
Figure 746208DEST_PATH_IMAGE011
（3）
According to the formula (3), the pressure difference inside and outside the flow channel of the ultrasonic gas meter measured by the differential pressure sensor has a certain relation with the average flow velocity of the gas medium in the flow channel, and the instantaneous flow is the product of the average flow velocity of the gas medium in the flow channel and the cross section area of the flow channel, so that the pressure difference inside and outside the flow channel of the ultrasonic gas meter has a certain relation with the instantaneous flow of the ultrasonic gas meter. Flow is sequentially introduced to obtain pressure difference data under different instantaneous flows, and a function model is used for carrying out data fitting on the pressure difference data and the instantaneous flows:
Figure 337727DEST_PATH_IMAGE012
wherein, in the process,
Figure 500855DEST_PATH_IMAGE052
which is indicative of a pressure difference between the two,
Figure 621257DEST_PATH_IMAGE014
is indicative of the instantaneous flow rate of the fluid,
Figure 384683DEST_PATH_IMAGE015
is a functional model of the pressure differential and instantaneous flow fit. With reference to equation (3), function
Figure 248734DEST_PATH_IMAGE053
Can be
Figure 266368DEST_PATH_IMAGE054
，
Figure 88831DEST_PATH_IMAGE055
、
Figure 73973DEST_PATH_IMAGE056
、
Figure 741715DEST_PATH_IMAGE057
Is the pressure difference data and instantaneous flow rate according to
Figure 613856DEST_PATH_IMAGE058
And (5) carrying out coefficient obtained by data fitting. Therefore, according to the functional relation between the pressure difference and the instantaneous flow, the theoretical pressure difference at the current moment can be deduced from the instantaneous flow at the current moment; the theoretical instantaneous flow at the current moment can be deduced from the actually measured pressure difference at the current moment.
In practical application, the structures of the flow channel and the cavity of the ultrasonic gas meters in different types can be different, so that the relation between the pressure difference and the flow needs to be measured through the device firstly. In this embodiment, a G6 ultrasonic gas meter is selected, a critical flow venturi nozzle method gas flow standard device is adopted, two gas pressure acquisition ports of a differential pressure sensor are respectively installed inside and outside a flow channel, a gas medium is air at a temperature of 20 ℃ in the experimental environment, and the relationship between the pressure difference and the flow is shown in the following table.
Figure 607220DEST_PATH_IMAGE059
As can be seen from the above table, when the flow rate is 2.5m3The pressure difference is 21.29Pa, and the flow range is (4-5) m3At the time of/h, the pressure difference is (40-60) Pa. In this embodiment, the selection
Figure 830391DEST_PATH_IMAGE058
The function model performs data fitting on the pressure difference data and the instantaneous flow. Wherein the gas density
Figure 285512DEST_PATH_IMAGE006
Taking 1.208kg/m3(temperature 20 ℃, pressure 101.6 kPa),
Figure 277739DEST_PATH_IMAGE060
、
Figure 176424DEST_PATH_IMAGE061
、
Figure 621312DEST_PATH_IMAGE062
is a fitting coefficient to be solved, and obtains the following functional relationship:
Figure 880124DEST_PATH_IMAGE063
（11）
the density of the gas is affected by the temperature, known as the absolute temperature
Figure 992437DEST_PATH_IMAGE064
Lower gas density
Figure 62024DEST_PATH_IMAGE065
(the present embodiment)
Figure 259787DEST_PATH_IMAGE066
Is a lubricating oil with the molecular weight of 293.15K,
Figure 56710DEST_PATH_IMAGE067
is 1.208 kg/L) at absolute temperature by the ideal gas equation
Figure 23529DEST_PATH_IMAGE068
Lower density
Figure 998439DEST_PATH_IMAGE069
：
Figure 949077DEST_PATH_IMAGE070
（12）
That is, the pressure difference versus flow becomes:
Figure 300424DEST_PATH_IMAGE071
（13）
(2) calculating instantaneous flow by using time difference method measurement principle
Figure 371017DEST_PATH_IMAGE014
Figure 782407DEST_PATH_IMAGE016
（4）
Figure 689183DEST_PATH_IMAGE017
（5）
In the above formulas (4) and (5),
Figure 578642DEST_PATH_IMAGE072
is the cross section area of the flow passage of the ultrasonic gas meter,
Figure 769320DEST_PATH_IMAGE019
is the average speed of the gas medium in the flow channel of the ultrasonic gas meter,
Figure 86032DEST_PATH_IMAGE073
is the length of the sound path,
Figure 480105DEST_PATH_IMAGE021
is the angle of the sound track,
Figure 156942DEST_PATH_IMAGE022
is the downstream propagation time of the ultrasonic wave in the gas medium,
Figure 952860DEST_PATH_IMAGE023
is the countercurrent propagation time of ultrasonic waves in a gas medium; wherein, the cross-sectional area of the flow passage
Figure 706052DEST_PATH_IMAGE072
Length of sound path
Figure 587421DEST_PATH_IMAGE073
Angle of sound channel
Figure 67950DEST_PATH_IMAGE021
The instantaneous flow can be calculated by the forward flow propagation time and the reverse flow propagation time of the ultrasonic wave in the gas medium
Figure 718374DEST_PATH_IMAGE024
. It can be seen that the forward flow propagation time and the backward flow propagation time of the ultrasonic wave in the gas medium are key measurement values of the instantaneous flow measurement of the ultrasonic gas meter, and the measurement precision is affected.
(3) Judging whether the wave is jumped or not, and adjusting the downstream propagation time and the upstream propagation time of the ultrasonic waves in the gas medium
Calculating the instantaneous flow at the current moment according to the time difference method measuring principle in the step (2)
Figure 642467DEST_PATH_IMAGE025
Then, the current theoretical pressure difference can be deduced according to the functional relation between the pressure difference and the instantaneous flow obtained in the step (1)
Figure 11132DEST_PATH_IMAGE026
：
Figure 295352DEST_PATH_IMAGE074
（14）
Differential pressure sensor for detecting pressure difference inside and outside flow channel of ultrasonic gas meter in real time
Figure 800282DEST_PATH_IMAGE075
When the difference between the measured pressure difference and the theoretical pressure difference
Figure DEST_PATH_IMAGE076
，
Figure DEST_PATH_IMAGE077
The maximum range of the allowable difference between the actually measured pressure difference and the theoretical pressure difference indicates that no wave jump phenomenon exists at the moment; when the difference between the measured pressure difference and the theoretical pressure difference
Figure DEST_PATH_IMAGE078
It is explained that the instantaneous flow rate is calculated with an error, and the forward propagation time and the backward propagation time of the ultrasonic wave in the gas medium need to be adjusted because a beat wave exists in the time measurement of the forward propagation time and the backward propagation time of the ultrasonic wave in the gas medium. According to the curve fitted in the present embodiment,
Figure DEST_PATH_IMAGE079
is 3.2Pa, so the maximum range of the allowable difference between the measured pressure difference and the theoretical pressure difference at the current moment
Figure DEST_PATH_IMAGE080
5Pa may be taken.
From measured pressure difference
Figure 488752DEST_PATH_IMAGE031
And the functional relation between the pressure difference and the instantaneous flow rate to deduce the theoretical instantaneous flow rate
Figure 610292DEST_PATH_IMAGE032
：
Figure DEST_PATH_IMAGE081
（15）
Theoretical instantaneous flow
Figure DEST_PATH_IMAGE082
The theoretical forward flow propagation time and the theoretical reverse flow propagation time of the ultrasonic wave in the gas medium approximately satisfy the following relations:
Figure DEST_PATH_IMAGE083
（6）
Figure 839148DEST_PATH_IMAGE035
（7）
in the formulae (6) and (7),
Figure DEST_PATH_IMAGE084
is the theoretical downstream propagation time of the ultrasonic wave in the gas medium,
Figure DEST_PATH_IMAGE085
is the theoretical counter-current propagation time of the ultrasonic wave in the gas medium,
Figure DEST_PATH_IMAGE086
is the propagation velocity of sound waves in a gaseous medium.
Figure 385536DEST_PATH_IMAGE066
Sound velocity in air at 293.15K
Figure 900700DEST_PATH_IMAGE086
Taking the value of 343.64m/s, the speed of sound is affected by temperature, at absolute temperature
Figure DEST_PATH_IMAGE087
Velocity of downward sound
Figure DEST_PATH_IMAGE088
：
Figure DEST_PATH_IMAGE089
(16)
Sound velocity in equation (16) when temperature changes
Figure DEST_PATH_IMAGE090
And (6) carrying out calculation in the formulas (6) and (7) to obtain the theoretical forward flow propagation time and the theoretical reverse flow propagation time of the ultrasonic wave in the gas medium.
In addition, when the wave jumping phenomenon occurs, the forward flow propagation time of the ultrasonic wave in the gas medium is actually measured
Figure DEST_PATH_IMAGE091
And the theoretical cocurrent propagation time of ultrasonic wave in gas medium
Figure 571853DEST_PATH_IMAGE036
Approximately differing by an integer number of ultrasonic transducer excitation signal periods, and actually measuring the counter-current propagation time of ultrasonic waves in a gas medium
Figure 214187DEST_PATH_IMAGE041
Theoretical counter-current propagation time with ultrasonic wave in gas medium
Figure 942977DEST_PATH_IMAGE042
Approximately differing by an integer number of ultrasonic transducer excitation signal periods, the approximate relationship is as follows:
Figure 114195DEST_PATH_IMAGE043
（8）
Figure 944748DEST_PATH_IMAGE044
（9）
in the formulas (8) and (9),
Figure 859615DEST_PATH_IMAGE045
is the period of the ultrasonic transducer excitation signal,
Figure 708491DEST_PATH_IMAGE046
、
Figure 316190DEST_PATH_IMAGE047
the wave number is indicated. The passing formula (6) -9 can adjust the actual measurement forward flow propagation time and the actual measurement reverse flow propagation time of the ultrasonic wave in the gas medium, thereby obtaining the instantaneous flow at the current moment
Figure DEST_PATH_IMAGE092
The following formula:
Figure 571722DEST_PATH_IMAGE049
（10）
sound path length of ultrasonic gas meter in this embodiment
Figure 805126DEST_PATH_IMAGE073
Is 0.0725m, vocal tract angle
Figure 259241DEST_PATH_IMAGE021
Is 45 ℃ and the cross-sectional area of the flow channel
Figure 37841DEST_PATH_IMAGE072
Is 0.0004m2Period of excitation signal of ultrasonic transducer
Figure DEST_PATH_IMAGE093
Is 5 us. A set of experimental data was selected to further illustrate that when the instantaneous flow rate was 4.89m3And/h, obtaining that the current theoretical differential pressure and the actual differential pressure are 1.69Pa and the difference between the current theoretical differential pressure and the actual differential pressure is less than 5Pa according to the functional relation between the differential pressure and the instantaneous flow, so that the phenomenon of wave jumping does not occur. It can now be further verified that the theoretical instantaneous flow is 4.79m from the measured pressure difference of 56.07Pa and the instantaneous flow as a function of the pressure difference and the instantaneous flow3Therefore, the theoretical forward propagation time and the theoretical backward propagation time of the ultrasonic wave in the gas medium are 209.36us and 212.62us respectively, and the ultrasonic wave in the gas mediumThe forward propagation time of the ultrasonic wave was found to be 210.3us, and the theoretical backward propagation time of the ultrasonic wave in the gas medium was found to be 212.59us, in which case the wave number was determined by the equations (8) and (9)
Figure 295516DEST_PATH_IMAGE046
、
Figure 83343DEST_PATH_IMAGE047
Is 0.
In summary, the invention installs the differential pressure sensor in the ultrasonic gas meter, detects the pressure difference inside and outside the flow channel of the ultrasonic gas meter through the differential pressure sensor, establishes the functional relationship between the pressure difference and the flow, and judges whether the wave jump problem exists in the downstream propagation time and the upstream propagation time of the ultrasonic wave in the gas medium measured in the time difference method, thereby preventing the occurrence of wrong measurement data. When the wave jumping phenomenon occurs, the pressure difference is used for correcting the forward flow propagation time and the reverse flow propagation time of the ultrasonic wave in the gas medium at the current moment, so that the instantaneous flow is adjusted, and the reliability and the accuracy of gas metering are improved.

Claims (1)

1. The method for improving the instantaneous flow measurement precision of the ultrasonic gas meter based on the pressure data is characterized by comprising the following steps of: installing a differential pressure sensor in the ultrasonic gas meter, wherein two gas pressure acquisition ports of the differential pressure sensor are respectively installed in a flow channel and outside the flow channel, so that the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter is detected, the downstream propagation time and the upstream propagation time of the ultrasonic wave in the gas at the current moment are measured by adopting a time difference method, and the instantaneous flow is calculated by utilizing the downstream propagation time and the upstream propagation time of the ultrasonic wave in a gas medium; judging whether a wave hopping problem exists or not according to the measured pressure difference and the instantaneous flow, and correcting the downstream propagation time and the upstream propagation time at the current moment by using pressure difference data when a wave hopping phenomenon occurs, so as to obtain the accurate instantaneous flow at the current moment;
the calculation of the instantaneous flow rate comprises the following steps:
(1) measuring the relation between pressure difference and instantaneous flow by using a gas flow standard device, (2) measuring the instantaneous flow by using a time difference method, (3) judging whether a wave jumps or not, and adjusting the downstream propagation time and the upstream propagation time of ultrasonic waves in a gas medium;
the step (1) of measuring the relation between the pressure difference and the instantaneous flow rate comprises the following steps:
installing a differential pressure sensor in the flow channel of the ultrasonic gas meter, and detecting the pressure difference inside and outside the flow channel of the ultrasonic gas meter through the differential pressure sensor; according to the Bernoulli equation, the pressure inside and outside the flow channel of the ultrasonic gas meter meets the following formula:
Figure DEST_PATH_IMAGE001
（1）
wherein,
Figure 895275DEST_PATH_IMAGE002
is the pressure in the cavity of the ultrasonic gas meter,
Figure DEST_PATH_IMAGE003
is the pressure in the flow channel of the ultrasonic gas meter,
Figure 999366DEST_PATH_IMAGE004
is the average flow velocity of the gas medium in the cavity of the ultrasonic gas meter,
Figure DEST_PATH_IMAGE005
is the average flow velocity of a gas medium in a flow channel of the ultrasonic gas meter,
Figure 716787DEST_PATH_IMAGE006
is the gas density;
from conservation of mass, we obtain:
Figure DEST_PATH_IMAGE007
（2）
wherein,
Figure 298947DEST_PATH_IMAGE008
is the sectional area in the cavity of the ultrasonic gas meter,
Figure DEST_PATH_IMAGE009
the cross section area in the flow channel of the ultrasonic gas meter;
the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter is obtained by the formulas (1) and (2)
Figure 51002DEST_PATH_IMAGE010
：
Figure DEST_PATH_IMAGE011
（3）
According to the formula (3), the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter measured by the differential pressure sensor is related to the average flow velocity of the gas medium in the flow channel, and the instantaneous flow is the product of the average flow velocity of the gas medium in the flow channel and the cross section area of the flow channel, so that the pressure difference between the inside and the outside of the flow channel of the ultrasonic gas meter is related to the instantaneous flow of the ultrasonic gas meter;
utilizing a gas flow standard device, sequentially introducing flow, obtaining pressure difference data under different instantaneous flows, and performing data fitting on the pressure difference data and the instantaneous flows by using a function model:
Figure 60415DEST_PATH_IMAGE012
wherein, in the process,
Figure DEST_PATH_IMAGE013
which is indicative of a pressure difference between the two,
Figure 61869DEST_PATH_IMAGE014
which is indicative of the instantaneous flow rate of the fluid,
Figure DEST_PATH_IMAGE015
is a function of the fit of the pressure difference and the instantaneous flowA model;
the step (2) of measuring the instantaneous flow by using the time difference method comprises the following steps:
Figure 650982DEST_PATH_IMAGE016
（4）
Figure DEST_PATH_IMAGE017
（5）
in the above formulas (4) and (5),
Figure 54282DEST_PATH_IMAGE018
is the cross section area of the flow passage of the ultrasonic gas meter,
Figure DEST_PATH_IMAGE019
is the average velocity of the gas medium in the flow passage of the ultrasonic gas meter,
Figure 985329DEST_PATH_IMAGE020
is the length of the sound path,
Figure DEST_PATH_IMAGE021
is the angle of the sound track,
Figure 926609DEST_PATH_IMAGE022
is the downstream propagation time of the ultrasonic wave in the gas medium,
Figure DEST_PATH_IMAGE023
is the countercurrent propagation time of ultrasonic waves in a gas medium; wherein, the cross section area of the flow passage
Figure 601304DEST_PATH_IMAGE018
Length of sound path
Figure 842798DEST_PATH_IMAGE024
Angle of sound channel
Figure 944746DEST_PATH_IMAGE025
The instantaneous flow can be calculated by the forward flow propagation time and the reverse flow propagation time of the ultrasonic wave in the gas medium
Figure DEST_PATH_IMAGE026
；
The step (3) is to judge whether the wave is jumped or not, and the steps of adjusting the forward flow propagation time and the backward flow propagation time of the ultrasonic wave in the gas medium are as follows:
calculating the instantaneous flow at the current moment according to the time difference method measuring principle in the step (2)
Figure 373323DEST_PATH_IMAGE027
Then, the current theoretical pressure difference can be deduced according to the functional relation between the pressure difference and the instantaneous flow obtained in the step (1)
Figure DEST_PATH_IMAGE028
(ii) a Differential pressure sensor for detecting pressure difference inside and outside flow channel of ultrasonic gas meter in real time
Figure 586129DEST_PATH_IMAGE029
When the difference between the measured pressure difference and the theoretical pressure difference is found
Figure DEST_PATH_IMAGE030
，
Figure 964021DEST_PATH_IMAGE031
The maximum range of the allowable difference between the actually measured pressure difference and the theoretical pressure difference indicates that no wave jump phenomenon exists at the moment; when the difference between the measured pressure difference and the theoretical pressure difference
Figure DEST_PATH_IMAGE032
To show that the instantaneous flow calculation is wrong, and the downstream propagation time and the upstream propagation time of the ultrasonic wave in the gas mediumIn the time measurement of the propagation time, a beat wave exists, so that the forward flow propagation time and the reverse flow propagation time of the ultrasonic wave in a gas medium need to be adjusted;
from measured pressure differences
Figure 486138DEST_PATH_IMAGE033
And the functional relation between the pressure difference and the instantaneous flow rate to deduce the theoretical instantaneous flow rate
Figure DEST_PATH_IMAGE034
，
Figure 152743DEST_PATH_IMAGE035
The theoretical forward flow propagation time and the theoretical reverse flow propagation time of the ultrasonic wave in the gas medium approximately satisfy the following relation:
Figure DEST_PATH_IMAGE036
（6）
Figure 418508DEST_PATH_IMAGE037
（7）
in the formulae (6) and (7),
Figure DEST_PATH_IMAGE038
is the theoretical downstream propagation time of the ultrasonic wave in the gas medium,
Figure 588589DEST_PATH_IMAGE039
is the theoretical countercurrent propagation time of ultrasonic waves in a gas medium,
Figure DEST_PATH_IMAGE040
is the propagation velocity of sound waves in a gaseous medium; in addition, when the wave jumping phenomenon occurs, the forward flow propagation time of the ultrasonic wave in the gas medium is actually measured
Figure 547187DEST_PATH_IMAGE041
And the theoretical cocurrent propagation time of ultrasonic wave in gas medium
Figure DEST_PATH_IMAGE042
Approximately differing by an integer number of ultrasonic transducer excitation signal periods, and actually measuring the counter-current propagation time of ultrasonic waves in a gas medium
Figure 232246DEST_PATH_IMAGE043
Theoretical counter-current propagation time with ultrasonic wave in gas medium
Figure DEST_PATH_IMAGE044
Approximately differing by an integer number of ultrasonic transducer excitation signal periods, the approximate relationship is as follows:
Figure 301702DEST_PATH_IMAGE045
（8）
Figure DEST_PATH_IMAGE046
（9）
in the formulas (8) and (9),
Figure 326290DEST_PATH_IMAGE047
is the period of the excitation signal of the ultrasonic transducer,
Figure 737680DEST_PATH_IMAGE048
、
Figure DEST_PATH_IMAGE049
represents a wave number; the passing formula (6) - (9) can adjust the actually measured downstream propagation time and the actually measured upstream propagation time of the ultrasonic wave in the gas medium, thereby obtaining the instantaneous flow at the current moment
Figure 362565DEST_PATH_IMAGE050
The following formula:
Figure DEST_PATH_IMAGE051
（10） 。
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003287450A (en) * 2002-03-28 2003-10-10 Osaka Gas Co Ltd Flowmeter
JP2004125481A (en) * 2002-09-30 2004-04-22 Babcock Hitachi Kk Sonic type method and apparatus for measuring temperature/flow of gas

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3508993B2 (en) * 1998-11-19 2004-03-22 矢崎総業株式会社 Flow rate measuring method and apparatus and electronic gas meter
JP2008510147A (en) * 2004-08-13 2008-04-03 エンテグリス インコーポレイテッド System and method for calibration of distribution devices
CN102564681A (en) * 2012-02-17 2012-07-11 浙江大学 Method for determining flowing state of medium in pipeline for ultrasonic gas meter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003287450A (en) * 2002-03-28 2003-10-10 Osaka Gas Co Ltd Flowmeter
JP2004125481A (en) * 2002-09-30 2004-04-22 Babcock Hitachi Kk Sonic type method and apparatus for measuring temperature/flow of gas

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Numerical Simulation of Transit-Time Ultrasonic Flowmeters by a Direct Approach;Adrian Luca;《IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control》;20160630;第63卷(第6期);全文 *
基于总线技术的井下流量采集传输系统设计;王恒;《计算机测量与控制》;20180531;第26卷(第5期);全文 *

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