Ultrasonic measurement method and system for fluid measurement

Abstract

The present invention belongs to the technical field of flow detection, and specifically relates to a fluid measurement method and system of ultrasonic metering. The fluid measurement system of ultrasonic metering includes a flow channel and an ultrasonic transducer for obtaining the flow velocity of the flow channel, wherein the main flow channel is connected to at least two branch flow channels arranged in parallel; at least one pair of ultrasonic transducers is arranged on the branch flow channel; and it also includes a processor, a signal sending and receiving unit, and a channel switching and control unit, wherein the processor is used to obtain the actual flow rate of the fluid according to the detection data of each branch flow channel. By dividing the area through which the fluid flows into a plurality of fluid circulation areas through a plurality of branch flow channels arranged in parallel, the fluid flow velocity of each branch flow circulation area is obtained respectively, that is, the fluid flow velocity obtained is the fluid flow velocity that completely covers the area through which the fluid flows, so the actual flow rate of the fluid is obtained according to the fluid flow velocity of each flow channel, which is the actual flow rate of the fluid obtained by completely covering the area through which the fluid flows, thereby improving the accuracy of measuring the actual flow rate of the fluid.

Description

Technical Field

[0001] The invention belongs to the technical field of flow detection, and in particular relates to an ultrasonically metered fluid measurement method and system. Background Art

[0002] The basic principle of ultrasonic flow measurement technology is to measure the fluid flow rate by using the flow velocity information of the fluid carried by ultrasonic waves when propagating in the fluid. The ultrasonic flow meter includes an ultrasonic transducer. By placing the ultrasonic transducer, the ultrasonic signal is propagated in the fluid at a certain angle to the direction of the fluid velocity. The ultrasonic transducer can detect the time difference of the ultrasonic signal's upstream and downstream transit time in the measuring pipeline, and the average flow rate of the fluid in the pipeline is obtained based on the time difference.

[0003] When the flow range measured by the flow meter is small, the flow channel is narrow, and the single-channel ultrasonic flow measurement can cover the area where the fluid flows, that is, the single channel can meet the measurement requirements of higher precision. When the flow range measured by the flow meter is large, it is necessary to reduce the pressure loss of the fluid by increasing the cross-sectional area of ​​the flow channel. At this time, a single channel cannot completely cover the area where the fluid flows, that is, the measured flight time difference cannot truly reflect the average flow velocity of the fluid, and there is a problem of low measurement accuracy. Summary of the invention

[0004] The object of the present invention is to provide an ultrasonically metered fluid measurement method and system to solve the problem in the prior art that when the measured flow range is large, a single sound channel cannot completely cover the area through which the fluid flows, resulting in low measurement accuracy.

[0005] In order to solve the above technical problems, the present invention provides a fluid measurement method using ultrasonic measurement, comprising the following steps:

[0006] 1) Obtaining flight time detection data of at least one pair of ultrasonic transducers on each branch channel of the fluid to be measured; the fluid to be measured is divided into at least two branch channels; the sound channel formed between the pair of ultrasonic transducers forms a certain angle with the flow direction of the fluid in the corresponding branch channel;

[0007] 2) Obtaining the fluid flow rate of each branch channel through time-of-flight detection data;

[0008] 3) According to the fluid flow rate of each branch channel, the actual fluid flow rate is obtained.

[0009] Its beneficial effects are: by obtaining the fluid flow rate of each branch channel, that is, dividing the fluid flow area into multiple fluid flow areas through multiple parallel branch channels, and obtaining the fluid flow rate of each branch flow area respectively, that is, the obtained fluid flow rate is the fluid flow rate that completely covers the fluid flow area. Therefore, the actual fluid flow rate is obtained according to the fluid flow rate of each channel, which is the actual fluid flow rate obtained by completely covering the fluid flow area. Compared with a single sound channel that cannot cover the fluid flow area, the accuracy of measuring the actual fluid flow rate is improved.

[0010] Furthermore, in step 3), the method for obtaining the actual flow rate of the fluid is: taking the arithmetic mean of the flow rates of the fluids in each branch channel within a measurement cycle as the average flow rate of the actual fluid, and multiplying the average flow rate by the sum of the cross-sectional areas of each branch channel to obtain the actual flow rate of the fluid. By first calculating the average flow rate of the actual fluid and then multiplying it by the sum of the cross-sectional areas of each branch channel to obtain the actual flow rate of the fluid, the process of obtaining the actual flow rate for each branch channel is simplified.

[0011] Furthermore, in step 3), the method for obtaining the actual flow rate of the fluid is: multiplying the fluid flow rate of each branch channel in a measurement cycle by the cross-sectional area of ​​the corresponding branch channel to obtain the fluid flow rate of each branch channel, and adding the fluid flow rates of each branch channel to obtain the actual flow rate of the fluid. By obtaining the fluid flow rate of each branch channel and taking the sum of the fluid flow rates as the actual flow rate of the fluid, the accuracy of the actual flow rate data of the fluid is ensured when the cross-sectional areas of each flow channel are not exactly the same.

[0012] Furthermore, in step 1), the flight time detection data of at least one pair of ultrasonic transducers on each branch channel of the fluid to be measured is obtained in one detection cycle; one detection cycle is one measurement cycle. By obtaining the fluid flow rate in each branch channel in one detection cycle, the fluid flow rate of the area through which the fluid flows in the detection cycle is truly reflected. Therefore, the actual fluid flow rate obtained based on the fluid flow rate in each branch channel obtained in one detection cycle is a more accurate actual fluid flow rate in this detection cycle. Therefore, this process improves the accuracy of the final actual fluid flow rate data.

[0013] Further, the fluid to be measured is divided into two branch channels, and in step 1), only the flight time detection data of at least one pair of ultrasonic transducers on one branch channel of the fluid to be measured is obtained in the first detection cycle, and only the flight time detection data of at least one pair of ultrasonic transducers on another branch channel of the fluid to be measured is obtained in the second detection cycle; wherein the first detection cycle and the second detection cycle constitute a measurement cycle. By obtaining the detection data of only one branch channel in one detection cycle, the measurement power consumption is reduced compared with obtaining the detection data of all branch channels in one detection cycle, and the detection data of another branch channel is obtained in the next detection cycle, that is, the two detection cycles realize the detection of full coverage of the fluid flow area, so the accuracy requirement is met, and therefore the actual flow of the fluid obtained according to the detection data of the two branch channels in two detection cycles (i.e., one measurement cycle) solves the problem that a single flow cannot completely cover the fluid flow area, resulting in low measurement accuracy, and reduces the measurement power consumption by the method of alternating measurement of the two channels during the detection cycle, so that the measurement power consumption and measurement accuracy reach a certain balance.

[0014] In order to solve the above technical problems, the present invention also provides an ultrasonic metering fluid measurement system, including a main channel through which the fluid to be measured is passed, and the main channel is connected to at least two branch channels arranged in parallel; at least one pair of ultrasonic transducers is arranged on the branch channel, which is used to obtain the flight time detection data of the fluid in the branch channel; according to the flight time detection data of each branch channel, the actual flow rate of the fluid is obtained; the sound channel formed between the pair of ultrasonic transducers is at a certain angle to the flow direction of the fluid in the corresponding branch channel.

[0015] Its beneficial effects are: the fluid flow rate of each flow channel is obtained by an ultrasonic transducer, that is, the fluid flow area is divided into multiple fluid flow areas by multiple branch channels arranged in parallel, and the fluid flow rate of each fluid flow area is obtained separately, that is, the obtained fluid flow rate is the fluid flow rate that completely covers the fluid flow area. Therefore, the actual fluid flow rate obtained according to the fluid flow rate of each branch channel is the actual fluid flow rate obtained by completely covering the fluid flow area. Compared with a single sound channel that cannot cover the fluid flow area, the accuracy of measuring the actual fluid flow rate is improved.

[0016] Furthermore, the process of obtaining the actual flow rate of the fluid is as follows: the flow rate of the fluid in each branch channel is obtained according to the flight time detection data; the arithmetic mean of the flow rates of the fluid in each branch channel within a measurement cycle is used as the average flow rate of the actual fluid, and the actual flow rate of the fluid is obtained by multiplying the average flow rate by the sum of the cross-sectional areas of each branch channel. By first calculating the average flow rate of the actual fluid and then multiplying it by the sum of the cross-sectional areas of each branch channel to obtain the actual flow rate of the fluid, the process of obtaining the actual flow rate for each branch channel is simplified.

[0017] Furthermore, the process of obtaining the actual flow rate of the fluid is as follows: obtaining the fluid flow rate of each branch channel according to the flight time detection data; multiplying the fluid flow rate of each branch channel in a measurement cycle by the cross-sectional area of ​​the corresponding branch channel to obtain the fluid flow rate of each branch channel, and adding the fluid flow rates of each branch channel to obtain the actual flow rate of the fluid. By obtaining the fluid flow rate of each branch channel and taking the sum of the fluid flow rates as the actual flow rate of the fluid, the accuracy of the actual flow rate data of the fluid is ensured when the cross-sectional areas of each branch channel are not exactly the same.

[0018] Furthermore, in one detection cycle, at least one pair of ultrasonic transducers on each branch channel obtains flight time detection data on each branch channel of the fluid to be tested; one detection cycle is a measurement cycle. By obtaining the fluid flow rate in each branch channel in one detection cycle, the fluid flow rate of the area through which the fluid flows in the detection cycle is truly reflected. Therefore, the actual fluid flow rate obtained based on the fluid flow rate in each branch channel obtained in one detection cycle is a more accurate actual fluid flow rate in this detection cycle. Therefore, this process improves the accuracy of the final actual fluid flow rate data.

[0019] Further, the main flow channel is connected to two parallel branch channels; in the first detection cycle, only at least one pair of ultrasonic transducers on one branch channel obtains the flight time detection data on the branch channel, and in the second detection cycle, only at least one pair of ultrasonic transducers on another branch channel obtains the flight time detection data on the branch channel; wherein the first detection cycle and the second detection cycle constitute a measurement cycle. By obtaining the detection data of only one branch channel in one detection cycle, the measurement power consumption is reduced compared to obtaining the detection data of all branch channels in one detection cycle, and the detection data of another branch channel is obtained in the next detection cycle, that is, the two detection cycles realize the detection of full coverage of the fluid flow area, so the accuracy requirement is met, and therefore the actual flow of the fluid obtained according to the detection data of the two branch channels in two detection cycles (i.e., one measurement cycle) solves the problem that a single channel cannot completely cover the fluid flow area, resulting in low measurement accuracy, and reduces the measurement power consumption by the method of alternating measurement of the two channels during the detection cycle, so that the measurement power consumption and measurement accuracy reach a certain balance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is an ultrasonic measurement principle diagram of a fluid measurement method and system of ultrasonic metering of the present invention;

[0021] Figure 2 It is a hardware schematic diagram of double-channel alternating measurement of an ultrasonically metered fluid measurement method and system of the present invention;

[0022] Figure 3It is a dual-channel fluid measurement diagram of an ultrasonic metering fluid of the present invention;

[0023] Figure 4 It is a flow diagram of the actual flow rate of an ultrasonic measurement method and a system of the double-channel alternate measurement average method of the present invention.

[0024] Among them, 1. one of the first pair of ultrasonic transducers; 2. one of the second pair of ultrasonic transducers; 3. one of the third pair of ultrasonic transducers; 4. one of the fourth pair of ultrasonic transducers; 5. the first branch channel; 6. the second branch channel. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0026] An embodiment of an ultrasonic metering fluid measurement system of the present invention:

[0027] The ultrasonic metering fluid measurement system of this embodiment includes a detection device and a control device, wherein the detection device includes parallel branch channels (at least two parallel branch channels) covering the area where the fluid flows, and an ultrasonic transducer for detecting the flow rate of the fluid in the channel is arranged on each channel, such as Figure 3 , is a schematic diagram of a detection device when two branch channels are connected in parallel, the first branch channel 5 and the second branch channel 6 divide the main channel into two branch channels (that is, the fluid enters the two branch channels after passing through the main channel), one of the first pair of ultrasonic transducers 1 and its corresponding other first pair of ultrasonic transducers, and one of the third pair of ultrasonic transducers 3 and its corresponding other third pair of ultrasonic transducers are used to detect the flow rate of the fluid flowing through the first branch channel, one of the second pair of ultrasonic transducers 2 and its corresponding other second pair of ultrasonic transducers, and one of the fourth pair of ultrasonic transducers 4 and its corresponding other fourth pair of ultrasonic transducers are used to detect the flow rate of the fluid flowing through the second branch channel, and the sound channel formed between each pair of ultrasonic transducers is at a certain angle to the flow direction of the fluid in the corresponding branch channel. By detecting the fluid flow rate in each branch channel, the actual flow rate of the fluid is obtained, thereby achieving fluid measurement that completely covers the area where the fluid flows, and ensuring the accuracy of the measurement result.

[0028] Among them, the transducer detection principle is as follows Figure 1 As shown in the figure, when the ultrasonic signal propagates in the fluid at a certain angle φ (φ is not equal to 90 degrees, that is, the sound channel formed between a pair of ultrasonic transducers is at a certain angle to the fluid flow direction in the corresponding branch channel), the ultrasonic sound velocity will be affected by the flow velocity of the fluid (gas or liquid) along the flow direction of the fluid (hereinafter referred to as "downward", and the sound velocity is referred to as "V d”) The speed of the ultrasonic wave emitted will increase, and the flight time (t d ) will decrease, against the direction of fluid flow (hereinafter referred to as "upward", the speed of sound is referred to as "V u ”) the speed of the ultrasonic wave emitted will decrease, and the flight time (t u ) will increase, making the flight time of the upward and downward ultrasonic waves in the fluid different. Therefore, the flow velocity (V) of the fluid in the pipeline can be calculated based on the flight time difference between the upward and downward ultrasonic waves. m ),Right now

[0029]

[0030] Where L is the ultrasonic transmission distance between a pair of transducers (such as Figure 1 The distance between the dotted line connecting transducer A and transducer B) is then used to accurately calculate the fluid flow rate based on the pipe cross-sectional area (S), i.e., Q = V m ×S. Based on this principle, being able to accurately and truly measure the flow velocity of each area of ​​the fluid cross section becomes a key factor in accurate measurement, which is particularly obvious in flow channels with large flow rates and large cross-sectional areas. Therefore, this embodiment achieves accurate and true measurement of the flow velocity of each area of ​​the fluid cross section by setting up multiple parallel branch flow channels that completely cover the area through which the fluid flows. The specific fluid measurement process of this embodiment is: simultaneous measurement process or alternating measurement process.

[0031] As one implementation method, the simultaneous measurement process is:

[0032] In the same detection cycle, at least one pair of transducers on each branch channel is turned on to measure the fluid flow rate of each branch channel. If only one pair of transducers is turned on on the branch channel, the fluid flow rate result detected by this transducer is used as the fluid flow rate of this branch channel. If more than one pair of transducers is turned on on the branch channel, the result obtained by arithmetic averaging the flow rate results detected by each pair of transducers is used as the fluid flow rate of this branch channel to obtain the fluid flow rate V of each branch channel. m-1 、V m-2 ,…,V m-n , (n is the number of branch channels) and then calculate the arithmetic average of the flow velocities of all branch channels in a measurement cycle (the measurement cycle is a cycle in which the fluid flow velocity is detected once for each branch channel and the flow velocity is calculated. In the simultaneous measurement process, one measurement cycle is one detection cycle) and then calculate the actual flow rate of the fluid using the average flow velocity, that is, (If n = 2, then This process detects the fluid flow rate in all flow channels within the same detection cycle, and performs arithmetic averaging on the fluid flow rates of all branch channels to obtain the average flow rate of the actual fluid. That is, this process truly reflects the fluid flow rate of the area through which the fluid flows within the detection cycle, and obtains a more accurate average flow rate of the actual fluid within the detection cycle. Therefore, based on this more accurate average flow rate of the actual fluid, the final actual fluid flow rate is more accurate and has higher precision. As another embodiment, after obtaining the fluid flow rate of each branch channel within a measurement cycle, the actual fluid flow rate can also be obtained by first obtaining the fluid flow rate of each branch channel, and then adding up the flow rates of each fluid, that is, Q1=S1*V m-1 、Q2=S2*V m-2 , …, Q n =S n *V m-n (where Q1, Q2, ..., Q n is the flow rate value of each branch channel, S1, S2, S n is the cross-sectional area of ​​each branch channel), the actual flow rate of the fluid is: Q = Q1 + Q2 + ... + Q n .

[0033] As another implementation, the alternating measurement process is:

[0034] This process divides the fluid to be tested into two branch channels, such as Figure 2 This is a hardware schematic diagram of dual-channel alternating measurement. The hardware device includes: a main control MCU, an analog switch, two pairs of transducers (one pair is set on each channel), a signal sending amplifier circuit, and a signal receiving amplifier circuit; the peripheral circuit of the entire device is simple, and the two channels share a set of signal sending and receiving amplifier circuits, saving hardware costs. The main control MCU transmits PWM as the excitation signal of the transducer, and first switches to the measurement state of channel 1 (i.e., the flow velocity detection device on one of the branch channels) through the channel control analog switch, and then switches the measurement up and down directions through the transducer control analog switch, so that the process of transducer A sending and transducer B receiving is realized alternately, and the output signal of the receiving transducer is sent to the main control MCU after signal amplification, and the up and down absolute flight time and flight time difference of channel 1 are obtained after processing by the MCU; similarly, the channel control analog switch can be switched to the measurement state of channel 2 (i.e., the flow velocity detection device on another branch channel), and the MCU obtains the up and down absolute flight time and flight time difference of channel 2, and then calculates the fluid flow rate of the two channels according to the fluid flow rate formula obtained according to the above transducer detection principle. That is, the fluid flow rates of the two channels are obtained in the above two detection cycles respectively, and the process of obtaining the final actual fluid flow rate according to the fluid flow rate obtained in this process is specifically as follows:

[0035] In the first detection cycle, the fluid flow rate V of channel 1 is measuredm-1.1 ;

[0036] In the second detection cycle, the fluid flow rate V of channel 2 is measured m-2.1 ; At this time, the actual flow rate of the fluid is: Where S is the sum of the cross-sectional areas of the two branch channels (the same below); as another embodiment, the actual flow rate of the fluid can be expressed as Q = S1 * V m-1.1 +S2*V m-2.1 Obtained, where S1 is the cross-sectional area of ​​the branch channel where the sound channel 1 is located, and S2 is the cross-sectional area of ​​the branch channel where the sound channel 2 is located (the same below);

[0037] In the third detection cycle, the fluid flow rate V of channel 1 is measured m-1.2 ; At this time, the actual flow rate of the fluid is: As another embodiment, the actual flow rate of the fluid can be expressed by Q=S1*V m-1.2 +S2*V m-2.1 get;

[0038] Repeat the above steps to perform continuous alternating measurements and sliding averages to continuously calculate the actual flow rate of the fluid; the actual flow rate of the fluid calculated by the above steps is shown in the following table:

[0039] Measuring cycle 1 2 3 4 5 … 2*n Channel 1 flow rate <![CDATA[V m-1.1 ]]> <![CDATA[V m-1.2 ]]> <![CDATA[V m-1.3 ]]> … Channel 2 flow rate <![CDATA[V m-2.1 ]]> <![CDATA[V m-2.2 ]]> … <![CDATA[V m-2.n ]]> Actual traffic Q1 Q2 Q3 Q4 … Q(2*n-1)

[0040] in,

[0041] As another embodiment, Q(2*n-1)=S1*V m-1.n +S2*V m-2.n .

[0042] That is, the above process is to open only a pair of transducers on one flow channel in each detection cycle, obtain the detection data of the transducer on the flow channel once, and the flow channels where the transducers opened in two adjacent detection cycles are different, and the actual fluid flow rate is obtained according to the fluid flow rate in the two different flow channels corresponding to the two adjacent detection cycles. Through this process, compared with obtaining the detection data of all flow channels in one detection cycle, the measurement power consumption is reduced, and the two adjacent detection cycles (that is, two adjacent detection cycles are one measurement cycle) realize the detection of complete coverage of the fluid flow area, so the accuracy requirement is met. Therefore, the actual fluid flow rate obtained according to the detection data of the two branch flow channels in the two detection cycles solves the problem that a single flow meter cannot completely cover the fluid flow area, resulting in low measurement accuracy, and the method of alternating dual flow channels during the detection cycle reduces the measurement power consumption, so that the measurement power consumption and measurement accuracy reach a certain balance, that is, without increasing the power consumption relative to the single-channel measurement, the flow meter ensures the measurement accuracy equivalent to that of the dual-channel measurement.

[0043] The actual fluid flow rate obtained through the above alternating measurement process is as follows Figure 4 .

[0044] After the actual flow rate of the fluid is calculated using the measurement method in the embodiment of the present invention, the measurement result can be further processed using a sliding average method or a Kalman filter method.

[0045] An ultrasonically metered fluid measurement method embodiment of the present invention:

[0046] The ultrasonic metering fluid measurement method of the present invention has been clearly introduced in the fluid measurement process part of an ultrasonic metering fluid measurement system embodiment, and will not be repeated here.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A fluid measurement method using ultrasonic measurement, characterized in that: include: The fluid to be tested is divided into two branch channels, and a pair of ultrasonic transducers is arranged on each branch channel; the sound channel formed between the pair of ultrasonic transducers is at a certain angle to the flow direction of the fluid in the corresponding branch channel; in each detection cycle, only the ultrasonic transducer on one branch channel is turned on, and the branch channels where the ultrasonic transducers turned on in two adjacent detection cycles are located are different, and the ultrasonic transducers on the two branch channels alternately perform the following processing in each detection cycle: obtain the flight time detection data of the corresponding branch channel, and obtain the fluid flow rate of the corresponding branch channel through the flight time detection data; The fluid flow rate of the first branch channel measured in the first detection cycle is V m-1.1 ; In the second detection cycle, the flow rate of the fluid in the second branch channel is measured. V m-2.1 , the actual fluid flow rate of the second detection cycle is or Q 1= S 1* V m-1.1 + S 2* V m-2.1 ,in S is the sum of the cross-sectional areas of the two branch channels, S 1 is the cross-sectional area of ​​the first branch channel, S 2 is the cross-sectional area of ​​the second branch channel; Measure the fluid flow rate of the first branch channel in the third detection cycle V m-1.2 , the actual fluid flow rate of the third detection cycle is or Q 2= S 1* V m-1.2 + S 2* V m-2.1 ; Repeat the above process to perform continuous alternating measurements and sliding averages to continuously calculate the actual flow rate of the fluid.

2. An ultrasonically metered fluid measurement system, comprising a main flow channel through which a fluid to be measured passes, characterized in that: The main flow channel is connected to two branch flow channels arranged in parallel; a pair of ultrasonic transducers is arranged on each branch flow channel to obtain flight time detection data of the fluid in the branch flow channel; the sound channel formed between the pair of ultrasonic transducers is at a certain angle to the flow direction of the fluid in the corresponding branch flow channel, and only one ultrasonic transducer on the branch flow channel is turned on in each detection cycle, and the branch flow channels where the ultrasonic transducers turned on in two adjacent detection cycles are different, and the process of obtaining the actual flow rate of the fluid to be measured includes: The ultrasonic transducers on the two branch flow channels perform the following processing alternately in each detection cycle: obtaining the flight time detection data of the corresponding branch flow channel, and obtaining the fluid flow rate of the corresponding branch flow channel through the flight time detection data; The fluid flow rate of the first branch channel measured in the first detection cycle is V m-1.1 ; In the second detection cycle, the flow rate of the fluid in the second branch channel is measured. V m-2.1 , the actual fluid flow rate of the second detection cycle is or Q 1= S 1* V m-1.1 + S 2* V m-2.1 ,in S is the sum of the cross-sectional areas of the two branch channels, S 1 is the cross-sectional area of ​​the first branch channel, S 2 is the cross-sectional area of ​​the second branch channel; Measure the fluid flow rate of the first branch channel in the third detection cycle V m-1.2 , the actual fluid flow rate of the third detection cycle is or Q 2= S 1* V m-1.2 + S 2* V m-2.1 ; Repeat the above process to perform continuous alternating measurements and sliding averages to continuously calculate the actual flow rate of the fluid.

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