Method and apparatus for determining fluid flow rate and ultrasonic flowmeter

Abstract

The present application provides a method and apparatus for determining fluid flow rate and an ultrasonic flowmeter. Based on the obtained flight time difference of the target signal, the reference sound speed at the current temperature is determined. Based on the reference sound speed and the flight time differences of the upstream and downstream signals at the current temperature, the reference signal flight time difference is determined. Further, according to the reference signal flight time difference and the target signal flight time difference, temperature compensation is performed on the reference sound speed to obtain the true sound speed at the current temperature. Then, based on the true sound speed, the fluid flow rate at the current temperature is determined; by adjusting the reference sound speed based on the reference signal flight time difference determined by the calibrated target signal flight time difference and the reference sound speed, the reference temperature is made to approach the true sound speed at the current temperature. Thus, the fluid flow rate at the current temperature is determined through the true sound speed with higher accuracy, reducing the influence of temperature changes on measurement accuracy and improving the accuracy of fluid flow rate measurement.

Description

Technical Field

[0001] The present application relates to the technical field of ultrasonic flowmeters, and particularly relates to a method and device for determining fluid flow velocity and an ultrasonic flowmeter. Background Art

[0002] An ultrasonic flowmeter measures the fluid flow velocity by using the time difference of sound waves propagating in the fluid. Since the propagation speed of ultrasonic waves in the fluid is affected by the fluid flow velocity, the propagation speed increases in the downstream direction and decreases in the upstream direction. Therefore, by measuring the time difference of the flight time of ultrasonic waves propagating in the downstream and upstream directions, the fluid flow velocity can be calculated. However, in practical applications, temperature changes will also affect the propagation speed of ultrasonic waves, thereby affecting the accuracy of fluid flow velocity measurement. Summary of the Invention

[0003] In view of this, the present application provides a method and device for determining fluid flow velocity and an ultrasonic flowmeter to improve the accuracy of fluid flow velocity measurement.

[0004] The technical solutions provided by the present application are as follows:

[0005] According to an embodiment of the first aspect of the present application, a method for determining fluid flow velocity is provided, and the method includes:

[0006] Obtain the target signal flight time difference; the target signal flight time difference refers to the flight time difference between the upstream signal at the calibration temperature and the upstream signal at the current temperature, or the flight time difference between the downstream signal at the calibration temperature and the downstream signal at the current temperature;

[0007] Determine the reference sound speed at the current temperature based on the target signal flight time difference;

[0008] Based on the reference sound speed and the flight time difference of the upstream and downstream signals at the current temperature, determine the reference signal flight time difference; the reference signal flight time difference refers to the flight time difference between the first signal and the second signal, the first signal is the upstream signal at the calibration temperature, and the second signal is the upstream signal at the current temperature, or the first signal is the downstream signal at the calibration temperature, and the second signal is the downstream signal at the current temperature;

[0009] Based on the reference signal flight time difference and the target signal flight time difference, perform temperature compensation on the reference sound speed to obtain the true sound speed at the current temperature, and determine the fluid flow velocity at the current temperature according to the true sound speed.

[0010] Optionally, the determining the reference sound speed at the current temperature based on the target signal flight time difference includes:

[0011] Determine the reference sound speed at the previous temperature according to the time difference of flight of the target signal, the time of flight of the target signal at the calibration temperature, and the specified flow rate;

[0012] Wherein, the target signal refers to an upstream signal or a downstream signal, and the time of flight of the target signal at the calibration temperature is calculated according to the obtained sound speed at the calibration temperature and the flow rate at the calibration temperature.

[0013] Optionally, the determining the reference signal flight time difference based on the reference sound speed and the time difference of flight of the upstream and downstream signals at the current temperature includes:

[0014] Calculate the reference flow rate corresponding to the reference sound speed at the current temperature according to the reference sound speed and the time difference of flight of the upstream and downstream signals at the current temperature;

[0015] Determine the time of flight of the target signal at the current temperature according to the reference sound speed and the reference flow rate, where the target signal refers to an upstream signal or a downstream signal;

[0016] Determine the reference signal flight time difference according to the time of flight of the target signal at the current temperature and the time of flight of the target signal at the calibration temperature; the time of flight of the target signal at the calibration temperature is calculated according to the obtained sound speed at the calibration temperature and the flow rate at the calibration temperature.

[0017] Optionally, the temperature compensation of the reference sound speed based on the reference signal flight time difference and the target signal flight time difference to obtain the true sound speed at the current temperature includes:

[0018] Perform a specified operation on the reference signal flight time difference and the target signal flight time difference to obtain a first operation result;

[0019] If the first operation result meets the first preset condition, determine the reference sound speed as the true sound speed at the current temperature;

[0020] If the first operation result does not meet the first preset condition, update the reference sound speed, and return to the step of determining the reference signal flight time difference based on the reference sound speed and the time difference of flight of the upstream and downstream signals at the current temperature.

[0021] Optionally, the specified operation includes: calculating the difference between the reference signal flight time difference and the target signal flight time difference; the first preset condition includes: the absolute value of the first operation result is less than a preset threshold; if the first operation result does not meet the first preset condition, updating the reference sound speed includes:

[0022] When the first operation result is greater than or equal to the preset threshold, determine whether the flight time difference of the reference signal is greater than the flight time difference of the target signal;

[0023] If the flight time difference of the reference signal is greater than the flight time difference of the target signal, increase the reference sound speed by a specified value;

[0024] If the flight time difference of the reference signal is less than the flight time difference of the target signal, decrease the reference sound speed by a specified value.

[0025] Optionally, the determining the fluid flow rate at the current temperature according to the true sound speed includes:

[0026] Calculate the fluid flow rate corresponding to the true sound speed at the current temperature according to the true sound speed and the flight time difference between the upstream and downstream signals at the current temperature.

[0027] Optionally, the determining the fluid flow rate at the current temperature according to the true sound speed includes:

[0028] Determine the reference flow rate at the current temperature corresponding to the true sound speed as the fluid flow rate at the current temperature.

[0029] According to an embodiment of the second aspect of the present application, there is provided a fluid flow rate determining device, the device includes:

[0030] An obtaining unit, configured to obtain the flight time difference of the target signal; the flight time difference of the target signal refers to the flight time difference between the upstream signal at the calibration temperature and the upstream signal at the current temperature, or the flight time difference between the downstream signal at the calibration temperature and the downstream signal at the current temperature;

[0031] A first determining unit, configured to determine the reference sound speed at the current temperature based on the flight time difference of the target signal;

[0032] A second determining unit, configured to determine the flight time difference of the reference signal based on the reference sound speed and the flight time difference between the upstream and downstream signals at the current temperature; the flight time difference of the reference signal refers to the flight time difference between the first signal and the second signal, the first signal is the upstream signal at the calibration temperature, the second signal is the upstream signal at the current temperature, or, the first signal is the downstream signal at the calibration temperature, the second signal is the downstream signal at the current temperature;

[0033] A third determining unit, configured to perform temperature compensation on the reference sound speed based on the flight time difference of the reference signal and the flight time difference of the target signal to obtain the true sound speed at the current temperature, and determine the fluid flow rate at the current temperature according to the true sound speed.

[0034] Optionally, the first determination unit is specifically configured to:

[0035] Determine the reference sound speed at the previous temperature according to the time difference of flight of the target signal, the time of flight of the target signal at the calibration temperature, and the specified flow rate;

[0036] Wherein, the target signal refers to an uplink signal or a downlink signal, and the time of flight of the target signal at the calibration temperature is calculated according to the sound speed at the calibration temperature and the flow rate at the calibration temperature that have been obtained;

[0037] And / or, the second determination unit is specifically configured to:

[0038] Calculate the reference flow rate corresponding to the reference sound speed at the current temperature according to the reference sound speed and the time difference of flight of the uplink and downlink signals at the current temperature;

[0039] Determine the time of flight of the target signal at the current temperature according to the reference sound speed and the reference flow rate, where the target signal refers to an uplink signal or a downlink signal;

[0040] Determine the time difference of flight of the reference signal according to the time of flight of the target signal at the current temperature and the time of flight of the target signal at the calibration temperature; the time of flight of the target signal at the calibration temperature is calculated according to the sound speed at the calibration temperature and the flow rate at the calibration temperature that have been obtained;

[0041] And / or, the third determination unit is specifically configured to:

[0042] Perform a specified operation on the time difference of flight of the reference signal and the time difference of flight of the target signal to obtain a first operation result;

[0043] If the first operation result meets a first preset condition, determine the reference sound speed as the true sound speed at the current temperature;

[0044] If the first operation result does not meet the first preset condition, update the reference sound speed, and return to the step of determining the time difference of flight of the reference signal based on the reference sound speed and the time difference of flight of the uplink and downlink signals at the current temperature;

[0045] And / or, the specified operation includes: calculating the difference between the time difference of flight of the reference signal and the time difference of flight of the target signal; the first preset condition includes: the absolute value of the first operation result is less than a preset threshold; the third determination unit is specifically configured to:

[0046] In the case where the first operation result is greater than or equal to the preset threshold, determine whether the time difference of flight of the reference signal is greater than the time difference of flight of the target signal;

[0047] If the time difference of flight of the reference signal is greater than the time difference of flight of the target signal, increase the reference sound speed by a specified value;

[0048] If the time difference of flight of the reference signal is less than the time difference of flight of the target signal, decrease the reference sound speed by a specified value;

[0049] And / or, the third determining unit is specifically configured to:

[0050] Calculate the fluid flow velocity corresponding to the true sound speed at the current temperature according to the true sound speed and the time difference of flight of the uplink and downlink signals at the current temperature;

[0051] And / or, the third determining unit is specifically configured to:

[0052] Determine the reference flow velocity at the current temperature corresponding to the true sound speed as the fluid flow velocity at the current temperature.

[0053] According to an embodiment of the third aspect of the present application, an ultrasonic flowmeter is provided, and the ultrasonic flowmeter includes:

[0054] A first transducer, configured to send a first ultrasonic signal to a second transducer and receive a second ultrasonic signal sent by the second transducer;

[0055] A second transducer, configured to send the second ultrasonic signal to the first transducer and receive the first ultrasonic signal sent by the first transducer;

[0056] A controller, configured to execute the method described in the first aspect.

[0057] As can be seen from the above technical solutions, the present application determines the reference sound speed at the current temperature based on the obtained time difference of flight of the target signal, and determines the time difference of flight of the reference signal based on the reference sound speed and the time difference of flight of the uplink and downlink signals at the current temperature. Further, according to the time difference of flight of the reference signal and the time difference of flight of the target signal, temperature compensation is performed on the reference sound speed to obtain the true sound speed at the current temperature, and then the fluid flow velocity at the current temperature is determined according to the true sound speed; based on the time difference of flight of the reference signal determined by the calibrated time difference of flight of the target signal and the reference sound speed, the reference sound speed is adjusted so that the reference temperature approaches the true sound speed at the current temperature, and then the fluid flow velocity at the current temperature is determined through the relatively accurate true sound speed, reducing the influence of temperature change on the measurement accuracy and improving the accuracy of fluid flow velocity measurement. Description of the Drawings

[0058] The drawings here are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application and used together with the specification to explain the principles of the present application.

[0059] Figure 1 Schematic diagram of the scenario of time-difference measurement by an ultrasonic flowmeter provided by an embodiment of the present application;

[0060] Figure 2 Flow chart of the method for determining fluid flow velocity provided by an embodiment of the present application;

[0061] Figure 3 Schematic diagram of a specific method for determining fluid flow velocity provided by an embodiment of the present application;

[0062] Figure 4 Schematic diagram of the structure of an ultrasonic flowmeter provided by an embodiment of the present application;

[0063] Figure 5 Structure diagram of a device for determining fluid flow velocity provided by an embodiment of the present application. Detailed implementation manners

[0064] In order to enable those skilled in the art to better understand the technical solutions provided by the embodiments of the present application, and to make the above-mentioned objects, features, and advantages of the embodiments of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0065] An ultrasonic flowmeter usually measures the fluid flow velocity by using the time difference of sound waves propagating in the fluid. Since the propagation speed of ultrasonic waves in the fluid is affected by the fluid flow velocity, the propagation speed increases in the downstream direction and decreases in the upstream direction. Therefore, by measuring the flight time difference of ultrasonic waves propagating in the downstream and upstream directions, the fluid flow velocity can be calculated.

[0066] Please refer to Figure 1 , Figure 1 which is a schematic diagram of the scenario of time-difference measurement by an ultrasonic flowmeter provided by an embodiment of the present application.

[0067] In this embodiment, the ultrasonic flowmeter may include a transducer 1, a transducer 2, and a controller ( Figure 1 not shown in the figure).

[0068] As Figure 1 shown, there is flowing fluid in the pipeline, and the transducer 1 and the transducer 2, which are mutually a transmitter and a receiver, are respectively deployed at two positions outside the pipeline.

[0069] In this embodiment, the fluid in the pipeline flows from right to left. Some parameters shown in the figure will be introduced below:

[0070] Among them, D represents the pipeline diameter; L represents the length of the sound wave transmission path, that is, the length of the dotted line connecting the transducer 1 and the transducer 2; Φ represents the angle between the sound wave transmission path and the pipeline; v represents the fluid flow velocity.

[0071] It is easy to understand that the acoustic wave flight time from transducer 1 to transducer 2 (denoted as the upstream signal flight time): , then . Among them, represents the acoustic wave flight time from transducer 1 to transducer 2, c represents the sound speed in this medium (fluid).

[0072] The acoustic wave flight time from transducer 2 to transducer 1 (denoted as the downstream signal flight time): Then . Among them, represents the acoustic wave flight time from transducer 2 to transducer 1.

[0073] Among them, , the difference between the upstream and downstream flight times .

[0074] In this embodiment, since the measurement errors of directly measuring the flight time, that is, directly measuring and are relatively large, generally the flight time difference is used to characterize and calculate the flow velocity of the fluid, that is:

[0075]

[0076] As can be seen from the above formula, the sound speed directly affects the calculation result of the flow velocity , and the flow velocity of the current fluid can be calculated based on the above formula through the sound speed c. However, in practical applications, temperature changes will affect the propagation speed of ultrasonic waves, that is, the propagation speed of ultrasonic waves in the same fluid is different at different temperatures.

[0077] Considering the influence of temperature on the propagation speed of ultrasonic waves, the propagation speed of ultrasonic waves in the fluid, that is, the sound speed can be expressed as:

[0078]

[0079] Among them, is the ultrasonic wave propagation speed at the reference temperature , is the temperature coefficient, is the current temperature.

[0080] In this case, if the influence of temperature changes is not considered and the flow velocity of the current fluid is directly determined by the sound speed at the calibrated temperature, it will affect the accuracy of the measurement of the flow velocity of the fluid at the current temperature.

[0081] Therefore, compensating for the temperature drift of the sound speed and further determining the fluid flow rate at the current temperature through the sound speed after temperature drift compensation are important measures to ensure the measurement accuracy of the ultrasonic time-difference flowmeter.

[0082] Based on this, the present application proposes a method for determining the fluid flow rate to improve the measurement accuracy of the time-difference flowmeter.

[0083] Please refer to Figure 2 , Figure 2 which is a flowchart of the method for determining the fluid flow rate provided in the embodiments of the present application.

[0084] As Figure 2 shown, the method may include the following steps:

[0085] Step 201, obtaining the flight time difference of the target signal.

[0086] In this embodiment, the flight time difference of the target signal refers to the flight time difference between the upstream signal at the calibration temperature and the upstream signal at the current temperature, or the flight time difference between the downstream signal at the calibration temperature and the downstream signal at the current temperature.

[0087] Exemplarily, the signal obtained by propagating the sound wave along the flow direction of the fluid (i.e., the angle between the sound wave propagation direction and the fluid flow direction is less than 90 degrees) for a specified distance may be denoted as the upstream signal, and the signal obtained by propagating the sound wave along the opposite direction of the fluid flow direction (i.e., the angle between the sound wave propagation direction and the fluid flow direction is greater than 90 degrees) for a specified distance may be denoted as the downstream signal.

[0088] In this embodiment, the specific steps for obtaining the flight time difference of the target signal may include:

[0089] Obtaining the target signal at the calibration temperature and the target signal at the current temperature, and inputting the target signal at the calibration temperature and the target signal at the current temperature into the cross-correlation algorithm to obtain the flight time difference of the target signal between the target signal at the calibration temperature and the target signal at the current temperature through the cross-correlation algorithm.

[0090] Wherein, the target signal refers to the upstream signal or the downstream signal. In the following specific examples, the target signal is taken as the upstream signal for description. The processing method of the downstream signal is similar to that of the upstream signal and will not be described separately hereinafter.

[0091] In this embodiment, the method for obtaining the relevant parameters at the calibration temperature will be described in detail below and will not be elaborated here.

[0092] So far, the description of step 201 ends. Next, step 202 is executed.

[0093] Step 202, determining the reference sound speed at the current temperature based on the flight time difference of the target signal.

[0094] In this embodiment, after obtaining the time difference of the target signal flight time through step 201, the reference sound speed at the current temperature can be obtained based on the time difference of the target signal flight time.

[0095] Specifically, the specific method for determining the reference sound speed at the current temperature based on the time difference of the target signal flight time may include:

[0096] Determine the reference sound speed at the previous temperature according to the time difference of the target signal flight time, the time difference of the target signal flight time at the calibration temperature, and the specified flow rate;

[0097] Among them, the target signal refers to the upstream signal or the downstream signal, and the time difference of the target signal flight time at the calibration temperature is calculated according to the obtained sound speed at the calibration temperature and the flow rate at the calibration temperature.

[0098] In this embodiment, the sound speed at the calibration temperature and the flow rate at the calibration temperature can be obtained first, and the time difference of the target signal flight time at the calibration temperature can be calculated according to the sound speed at the calibration temperature and the flow rate at the calibration temperature.

[0099] Next, the method for obtaining the sound speed and the flow rate at the calibration temperature will be described first.

[0100] First, obtain the measured sound speed at the calibration temperature , and determine the time difference of the flight time of the upstream and downstream signals at the calibration temperature according to the cross-correlation algorithm , and then through the foregoing relational expression between the sound speed, the time difference of the flight time of the upstream and downstream signals, and the flow rate:

[0101]

[0102] Substitute and to obtain the flow rate at the calibration temperature .

[0103] Among them, the process of determining the time difference of the flight time of the upstream and downstream signals at the calibration temperature through the cross-correlation algorithm is a common method in the related art and will not be elaborated here.

[0104] Similarly, the measured flow rate at the calibration temperature can also be obtained first , and determine the time difference of the flight time of the upstream and downstream signals at the calibration temperature according to the cross-correlation algorithm , and then substitute and into the above relational expression to obtain the sound speed at the calibration temperature , and the present application does not limit this.

[0105] After determining the sound speed at the calibration temperature and the flow velocity it is possible to further calculate the target signal flight time at the calibration temperature based on the sound speed at the calibration temperature and the flow velocity at the calibration temperature.

[0106] Specifically, taking the target signal as the uplink signal as an example, based on the sound speed at the calibration temperature and the flow velocity at the calibration temperature the target signal flight time at the calibration temperature (the uplink signal flight time at the calibration temperature) can be calculated:

[0107]

[0108] where is the target signal flight time at the calibration temperature, which is not directly measured but calculated through the relationship between the flight distance and the flight speed.

[0109] Furthermore, after determining the target signal flight time at the calibration temperature, the reference sound speed at the previous temperature can be determined based on the target signal flight time difference, the target signal flight time at the calibration temperature, and the specified flow velocity.

[0110] Specifically, still taking the target signal as the uplink signal as an example, since:

[0111]

[0112] where is the target signal flight time difference determined in step 201, is the target signal (uplink signal) flight time at the current temperature, is the target signal (uplink signal) flight time at the calibration temperature, c is the sound speed at the current temperature, and v is the flow velocity at the current temperature.

[0113] After performing equivalent transformation on the above formula, we can obtain:

[0114]

[0115] That is, the relationship between the sound speed and the flow velocity at the current temperature is obtained.

[0116] At this time, a specified flow velocity, such as the specified flow velocity can be preset, and this specified flow velocity is substituted into the above formula to calculate a reference sound speed at the current temperature .

[0117] In this embodiment, the specified flow velocity can be any preset value, and this application does not limit it. The reference sound speed at the current temperature determined according to the specified flow velocity It is an estimated value, and further, the value of the reference sound speed will be adjusted according to the subsequent calculation results so that the reference sound speed approaches the true sound speed at the current temperature.

[0118] So far, the description of step 202 ends, and then step 203 is executed.

[0119] Step 203: Determine the reference signal flight time difference based on the reference sound speed and the flight time difference between the uplink and downlink signals at the current temperature.

[0120] In this embodiment, the reference signal flight time difference refers to the flight time difference between the first signal and the second signal. The first signal is the uplink signal at the calibration temperature, and the second signal is the uplink signal at the current temperature, or the first signal is the downlink signal at the calibration temperature, and the second signal is the downlink signal at the current temperature.

[0121] After determining the reference sound speed, the reference signal flight time difference corresponding to the reference sound speed can be calculated based on the reference sound speed and the flight time difference between the uplink and downlink signals at the current temperature. This reference signal flight time difference represents the flight time difference between the uplink signal at the calibration temperature calculated according to the reference sound speed and the uplink signal at the current temperature, or the flight time difference between the downlink signal at the calibration temperature and the downlink signal at the current temperature.

[0122] Exemplarily, the specific method for determining the reference signal flight time difference based on the reference sound speed and the flight time difference between the uplink and downlink signals at the current temperature may include:

[0123] Calculate the reference flow velocity corresponding to the reference sound speed at the current temperature according to the reference sound speed and the flight time difference between the uplink and downlink signals at the current temperature;

[0124] Determine the target signal flight time at the current temperature according to the reference sound speed and the reference flow velocity. The target signal refers to the uplink signal or the downlink signal;

[0125] Determine the reference signal flight time difference according to the target signal flight time at the current temperature and the target signal flight time at the calibration temperature; the target signal flight time at the calibration temperature is calculated according to the obtained sound speed at the calibration temperature and the flow velocity at the calibration temperature.

[0126] In this embodiment, the flight time difference between the uplink and downlink signals at the current temperature can be obtained by the cross-correlation algorithm, which will not be elaborated here.

[0127] After obtaining the flight time difference between the uplink and downlink signals at the current temperature, the reference flow velocity corresponding to the reference sound speed at the current temperature can be calculated according to the reference sound speed and the flight time difference between the uplink and downlink signals at the current temperature.

[0128] Specifically, the reference sound velocity and the time difference of the round-trip signal flight at the current temperature can be substituted into the relational expression among the sound velocity, the time difference of the round-trip signal flight, and the flow velocity described above:

[0129]

[0130] to obtain the reference flow velocity corresponding to the reference sound velocity .

[0131] Furthermore, the target signal flight time at the current temperature can be determined according to the reference sound velocity and the reference flow velocity.

[0132] Taking the target signal as the uplink signal as an example, the target signal flight time at the current temperature is: , where is the reference sound velocity at the current temperature, is the reference flow velocity corresponding to the above reference sound velocity at the current temperature.

[0133] After determining the target signal flight time at the current temperature, the reference signal flight time difference can be determined according to the target signal flight time at the current temperature and the target signal flight time at the calibration temperature.

[0134] Specifically, taking the target signal as the uplink signal as an example, the calculation method of the reference signal flight time difference is:

[0135]

[0136] where is the reference signal flight time difference (i.e., the difference between the uplink signal flight time at the current temperature calculated according to the reference sound velocity and the reference flow velocity and the uplink signal flight time at the calibration temperature that has been obtained).

[0137] So far, the description of step 203 ends, and step 204 is executed below.

[0138] Step 204: Based on the reference signal flight time difference and the target signal flight time difference, perform temperature compensation on the reference sound velocity to obtain the true sound velocity at the current temperature, and determine the fluid flow velocity at the current temperature according to the true sound velocity.

[0139] In this embodiment, the reference signal time-of-flight difference determined in step 203 is actually the difference between the uplink signal time-of-flight at the calibrated temperature and the current temperature calculated based on the reference sound speed, or the difference between the downlink signal time-of-flight at the calibrated temperature and the current temperature. Further, the reference signal time-of-flight difference (calculated value) can be compared with the target signal time-of-flight difference (accurate value) determined in step 201, so as to adjust the reference sound speed according to the error value between the two, so that the reference signal time-of-flight difference gradually approaches the target signal time-of-flight difference, that is, the reference sound speed gradually approaches the true sound speed at the current temperature, so as to realize the temperature compensation of the sound speed.

[0140] Exemplarily, based on the reference signal time-of-flight difference and the target signal time-of-flight difference, the specific method for temperature compensation of the reference sound speed to obtain the true sound speed at the current temperature includes:

[0141] Performing a specified operation on the reference signal time-of-flight difference and the target signal time-of-flight difference to obtain a first operation result;

[0142] If the first operation result meets the first preset condition, the reference sound speed is determined as the true sound speed at the current temperature;

[0143] If the first operation result does not meet the first preset condition, the reference sound speed is updated, and the step of determining the reference signal time-of-flight difference based on the reference sound speed and the uplink and downlink signal time-of-flight differences at the current temperature is returned.

[0144] As an embodiment, performing a specified operation on the reference signal time-of-flight difference and the target signal time-of-flight difference to obtain a first operation result can be calculating the difference between the reference signal time-of-flight difference and the target signal time-of-flight difference, or calculating the relative error, percentage error, etc. between the reference signal time-of-flight difference and the target signal time-of-flight difference. The present application does not limit this.

[0145] Taking the specified operation as calculating the difference between the reference signal time-of-flight difference and the target signal time-of-flight difference as an example, the corresponding first preset condition can be that the absolute value of the first operation result is less than a preset threshold.

[0146] When the absolute value of the difference between the reference signal time-of-flight difference and the target signal time-of-flight difference is less than the preset threshold, it indicates that the error between the reference signal time-of-flight difference and the target signal time-of-flight difference is extremely small. At this time, the current reference sound speed can be determined as the true sound speed at the current temperature.

[0147] In this embodiment, the size of the preset threshold can be determined according to the resolution of the reference signal time-of-flight difference and the target signal time-of-flight difference.

[0148] When the absolute value of the difference between the reference signal time-of-flight difference and the target signal time-of-flight difference is greater than or equal to a preset threshold, it indicates that there is a large error between the reference signal time-of-flight difference and the target signal time-of-flight difference. At this time, the reference sound speed can be adjusted, and the step of determining the reference signal time-of-flight difference based on the reference sound speed and the uplink and downlink signal time-of-flight differences at the current temperature is returned, so that the reference sound speed approaches the true sound speed at the current temperature.

[0149] Specific adjustment methods can be as follows:

[0150] Judge whether the reference signal time-of-flight difference is greater than the target signal time-of-flight difference;

[0151] If the reference signal time-of-flight difference is greater than the target signal time-of-flight difference, increase the reference sound speed by a specified value;

[0152] If the reference signal time-of-flight difference is less than the target signal time-of-flight difference, decrease the reference sound speed by a specified value.

[0153] In this embodiment, the size of the specified value can be set according to the size of the difference between the reference signal time-of-flight difference and the target signal time-of-flight difference. For example, the size of the specified value is positively correlated with the size of the difference between the reference signal time-of-flight difference and the target signal time-of-flight difference.

[0154] As an embodiment, the size of the specified value can also be traversed using the dichotomy method, and the present application does not limit this.

[0155] For example, the following formula is used to calculate the reference signal time-of-flight difference and the target signal time-of-flight difference:

[0156]

[0157] Among them, refers to the reference signal time-of-flight difference, refers to the target signal time-of-flight difference, refers to the preset threshold.

[0158] When the reference signal time-of-flight difference and the target signal time-of-flight difference meet the above conditions, increase or decrease the reference sound speed by a specified value, update the reference sound speed, and return the step of determining the reference signal time-of-flight difference based on the reference sound speed and the uplink and downlink signal time-of-flight differences at the current temperature until the absolute value of the difference between the reference signal time-of-flight difference and the target signal time-of-flight difference is less than the above preset threshold.

[0159] In this embodiment, it is easy to understand that The reference signal flight time difference is determined by referring to the sound speed and the reference flow rate. Since the reference sound speed and the reference flow rate are not precise enough, there may still be a large error between the determined reference signal flight time difference and the target signal flight time difference determined in step 201. The overall concept of this application is to adjust the reference sound speed so that the reference signal flight time difference approaches the target signal flight time difference, so as to make the reference sound speed approach the true sound speed at the current temperature and the reference flow rate approach the true flow rate at the current temperature.

[0160] In this embodiment, after adjusting the reference sound speed to determine the true sound speed at the current temperature, the fluid flow rate at the current temperature, that is, the true flow rate at the current temperature, can be determined according to the true sound speed. Specifically, the true sound speed and the round-trip signal flight time difference at the current temperature can be substituted into the formula to obtain the true flow rate at the current temperature:

[0161]

[0162] Wherein, is the true flow rate at the current temperature, is the true sound speed at the current temperature, is the round-trip signal flight time difference at the current temperature.

[0163] As an embodiment, actually in the process of determining the true sound speed, the true flow rate corresponding to the true sound speed has been determined, that is, before taking the reference sound speed as the true sound speed, the reference flow rate corresponding to the determined reference sound speed is the true flow rate corresponding to the true sound speed.

[0164] So far, the description of step 204 is completed.

[0165] So far, the description of Figure 2 the flowchart of the fluid flow rate method is completed.

[0166] This application determines the reference sound speed at the current temperature based on the obtained target signal flight time difference, and determines the reference signal flight time difference based on the reference sound speed and the round-trip signal flight time difference at the current temperature. Further, according to the reference signal flight time difference and the target signal flight time difference, temperature compensation is performed on the reference sound speed to obtain the true sound speed at the current temperature, and then the fluid flow rate at the current temperature is determined according to the true sound speed; based on the calibrated target signal flight time difference and the reference signal flight time difference determined by the reference sound speed, the reference sound speed is adjusted so that the reference temperature approaches the true sound speed at the current temperature, and then the fluid flow rate at the current temperature is determined by the relatively accurate true sound speed, reducing the influence of temperature change on the measurement accuracy, improving the accuracy of fluid flow rate measurement, and realizing high-precision fluid flow rate measurement without measuring temperature.

[0167] The method proposed in this application will be described below. Figure 3

[0168] Please refer to Figure 3 , Figure 3 which is a schematic diagram of a specific method for determining the fluid flow rate provided by an embodiment of this application.

[0169] As Figure 3 shown, taking the scenario shown in Figure 1 as an example, the method for determining the fluid flow rate proposed in this application may include the following steps:

[0170] Based on the obtained sound speed at the calibrated temperature , calculate the round-trip signal flight time difference at the calibrated temperature through the cross-correlation algorithm , and thus obtain the flow rate at the calibrated temperature according to the relationship among the sound speed, flow rate, and round-trip signal flight time difference ;

[0171] Among them, taking the target signal as the upstream signal as an example, assume = 1460 m / s, = 10^5 ps, the angle between the fluid flow rate and the acoustic wave propagation direction of the upstream signal, and the inner diameter D of the pipeline is 0.1 m, then = 2.6379 m / s.

[0172] Calculate that the accurate flight time of the upstream signal at the calibrated temperature is a fixed constant:

[0173]

[0174] Furthermore, obtain the target signal flight time difference through the cross-correlation algorithm, that is, the flight time difference between the upstream and upstream signals at the calibrated temperature and the current temperature , and because

[0175]

[0176] Among them, is the target signal flight time difference, is the flight time of the target signal (upstream signal) at the current temperature, is the flight time of the target signal (upstream signal) at the calibrated temperature, c is the sound speed at the current temperature, and v is the flow rate at the current temperature.

[0177] Then, the relationship between the sound speed and the flow rate at the current temperature can be deduced:

[0178]

[0179] ​Assume the specified flow rate , = 1000 ps, calculate the reference sound speed = 1461 m / s;

[0180] Substitute the reference sound speed into the relational expression between the sound speed, the flow rate, and the round-trip signal flight time difference. Assume = 10^4 ps, , and obtain the reference flow rate ; where is the round-trip signal flight time difference at the current temperature and can be obtained through the cross-correlation algorithm.

[0181] According to the reference sound speed and the reference flow rate calculate the reference signal flight time difference ;

[0182] If , then increase or decrease the reference sound speed by a specified value, and return the step of substituting the reference sound speed into the relational expression between the sound speed, the flow rate, and the round-trip signal flight time difference to calculate the reference flow rate. Where is the preset threshold value, such as . Continuously iterate and approximate to calculate the true sound speed according to the threshold value (i.e., the resolution of the flight time difference). The reference flow rate corresponding to the true sound speed is the fluid flow rate at the current temperature.

[0183] Thus, the description of Figure 3 ends.

[0184] Please refer to Figure 4 , Figure 4 which is a schematic structural diagram of an ultrasonic flowmeter proposed in an embodiment of the present application.

[0185] As shown in Figure 4 , the ultrasonic flowmeter includes:

[0186] A first transducer, configured to send a first ultrasonic signal to a second transducer and receive a second ultrasonic signal sent by the second transducer;

[0187] A second transducer, configured to send a second ultrasonic signal to the first transducer and receive the first ultrasonic signal sent by the first transducer;

[0188] A controller, configured to execute the method as shown in Figure 2 .

[0189] In this embodiment, the controller can be connected to the first transducer and the second transducer through a control bus to achieve communication, and the present application does not limit this.

[0190] Among them, the method for determining the fluid flow rate executed by the controller has been described in detail above and will not be elaborated here.

[0191] So far, the description of Figure 4 the ultrasonic flowmeter is completed.

[0192] Please refer to Figure 5 , Figure 5 which is a structural diagram of a fluid flow rate determination device proposed in an embodiment of the present application. As Figure 5 shown, the device may include an acquisition unit 501, a first determination unit 502, a second determination unit 503, and a third determination unit 504. Specifically, the device includes:

[0193] The acquisition unit 501 is configured to acquire the flight time difference of the target signal; the flight time difference of the target signal refers to the flight time difference between the upstream signal at the calibration temperature and the upstream signal at the current temperature, or the flight time difference between the downstream signal at the calibration temperature and the downstream signal at the current temperature;

[0194] The first determination unit 502 is configured to determine the reference sound speed at the current temperature based on the flight time difference of the target signal;

[0195] The second determination unit 503 is configured to determine the flight time difference of the reference signal based on the reference sound speed and the flight time difference of the upstream and downstream signals at the current temperature; the flight time difference of the reference signal refers to the flight time difference between the first signal and the second signal, the first signal is the upstream signal at the calibration temperature, the second signal is the upstream signal at the current temperature, or the first signal is the downstream signal at the calibration temperature, and the second signal is the downstream signal at the current temperature;

[0196] The third determination unit 504 is configured to perform temperature compensation on the reference sound speed based on the flight time difference of the reference signal and the flight time difference of the target signal to obtain the true sound speed at the current temperature, and determine the fluid flow rate at the current temperature according to the true sound speed.

[0197] Optionally, the first determination unit 502 is specifically configured to:

[0198] Determine the reference sound speed at the current temperature according to the flight time difference of the target signal, the flight time of the target signal at the calibration temperature, and the specified flow rate;

[0199] Among them, the target signal refers to the upstream signal or the downstream signal, and the flight time of the target signal at the calibration temperature is calculated according to the sound speed at the calibration temperature and the flow rate at the calibration temperature that have been obtained;

[0200] And / or, the second determination unit 503 is specifically configured to:

[0201] Calculate the reference flow velocity corresponding to the reference sound velocity at the current temperature according to the reference sound velocity and the time difference of the uplink and downlink signals at the current temperature;

[0202] Determine the target signal flight time at the current temperature according to the reference sound velocity and the reference flow velocity, where the target signal refers to the uplink signal or the downlink signal;

[0203] Determine the reference signal flight time difference according to the target signal flight time at the current temperature and the target signal flight time at the calibration temperature; the target signal flight time at the calibration temperature is calculated according to the obtained sound velocity and flow velocity at the calibration temperature;

[0204] And / or, the third determination unit 504 is specifically configured to:

[0205] Perform a specified operation on the reference signal flight time difference and the target signal flight time difference to obtain a first operation result;

[0206] If the first operation result meets the first preset condition, determine the reference sound velocity as the true sound velocity at the current temperature;

[0207] If the first operation result does not meet the first preset condition, update the reference sound velocity, and return to the step of determining the reference signal flight time difference based on the reference sound velocity and the time difference of the uplink and downlink signals at the current temperature;

[0208] And / or, the specified operation includes: calculating the difference between the reference signal flight time difference and the target signal flight time difference; the first preset condition includes: the absolute value of the first operation result is less than a preset threshold; the third determination unit 504 is specifically configured to:

[0209] When the first operation result is greater than or equal to the preset threshold, determine whether the reference signal flight time difference is greater than the target signal flight time difference;

[0210] If the reference signal flight time difference is greater than the target signal flight time difference, increase the reference sound velocity by a specified value;

[0211] If the reference signal flight time difference is less than the target signal flight time difference, decrease the reference sound velocity by a specified value;

[0212] And / or, the third determination unit 504 is specifically configured to:

[0213] Calculate the fluid flow velocity corresponding to the true sound velocity at the current temperature according to the true sound velocity and the time difference of the uplink and downlink signals at the current temperature;

[0214] And / or, the third determination unit 504 is specifically configured to:

[0215] Determine the reference flow rate at the current temperature corresponding to the true sound speed as the fluid flow rate at the current temperature.

[0216] Thus far, the description of Figure 5 the fluid flow rate determination device in

[0217] Correspondingly, an embodiment of the present application further provides a computer-readable storage medium. A number of computer instructions are stored on the computer-readable storage medium. When the computer instructions are executed, the methods disclosed in the above examples of the present application can be implemented.

[0218] Exemplarily, the above computer-readable storage medium can be any electronic, magnetic, optical, or other physical storage device that can contain or store information, such as executable instructions, data, etc. For example, the computer-readable storage medium can be: RAM (Random Access Memory), volatile memory, non-volatile memory, flash memory, storage drives (such as hard disk drives), solid-state drives, any type of storage disk (such as optical discs, DVDs, etc.), or similar storage media, or a combination thereof.

[0219] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for determining fluid flow rate, characterized in that, The method includes: Obtaining the time difference of flight of the target signal; the time difference of flight of the target signal refers to the time difference of flight between the upstream signal at the calibrated temperature and the upstream signal at the current temperature, or the time difference of flight between the downstream signal at the calibrated temperature and the downstream signal at the current temperature; Determining the reference sound speed at the current temperature according to the time difference of flight of the target signal, the time of flight of the target signal at the calibrated temperature, and the specified flow rate; the time of flight of the target signal at the calibrated temperature is calculated according to the obtained sound speed at the calibrated temperature and the flow rate at the calibrated temperature; Calculating the reference flow rate corresponding to the reference sound speed at the current temperature according to the reference sound speed and the time difference of flight of the upstream and downstream signals at the current temperature; determining the time of flight of the target signal at the current temperature according to the reference sound speed and the reference flow rate; determining the time difference of flight of the reference signal according to the time of flight of the target signal at the current temperature and the time of flight of the target signal at the calibrated temperature; the time of flight of the target signal at the calibrated temperature is calculated according to the obtained sound speed at the calibrated temperature and the flow rate at the calibrated temperature; the time difference of flight of the reference signal refers to the time difference of flight between the first signal and the second signal, the first signal is the upstream signal at the calibrated temperature, the second signal is the upstream signal at the current temperature, or the first signal is the downstream signal at the calibrated temperature, and the second signal is the downstream signal at the current temperature; Performing a specified operation on the time difference of flight of the reference signal and the time difference of flight of the target signal to obtain a first operation result; if the first operation result meets the first preset condition, determining the reference sound speed as the true sound speed at the current temperature, and determining the fluid flow rate at the current temperature according to the true sound speed; if the first operation result does not meet the first preset condition, updating the reference sound speed, and returning to the step of calculating the reference flow rate corresponding to the reference sound speed at the current temperature according to the reference sound speed and the time difference of flight of the upstream and downstream signals at the current temperature.

2. The method according to claim 1, characterized in that, The specified operation includes: calculating the difference between the time difference of flight of the reference signal and the time difference of flight of the target signal; the first preset condition includes: the absolute value of the first operation result is less than a preset threshold; if the first operation result does not meet the first preset condition, updating the reference sound speed includes: When the first operation result is greater than or equal to the preset threshold, determining whether the time difference of flight of the reference signal is greater than the time difference of flight of the target signal; If the time difference of flight of the reference signal is greater than the time difference of flight of the target signal, increasing the reference sound speed by a specified value; If the time difference of flight of the reference signal is less than the time difference of flight of the target signal, decreasing the reference sound speed by a specified value.

3. The method according to claim 1, wherein The determining the fluid flow rate at the current temperature according to the true sound speed includes: Calculating the fluid flow rate corresponding to the true sound speed at the current temperature according to the true sound speed and the time difference of flight of the upstream and downstream signals at the current temperature.

4. The method according to claim 1, characterized in that, Determining the fluid flow rate at the current temperature according to the true sound speed includes: Determining the reference flow rate at the current temperature corresponding to the true sound speed as the fluid flow rate at the current temperature.

5. A fluid flow velocity determination device, characterized in that, The device includes: An acquisition unit configured to acquire the flight time difference of the target signal; the flight time difference of the target signal refers to the flight time difference between the upstream signal at the calibration temperature and the upstream signal at the current temperature, or the flight time difference between the downstream signal at the calibration temperature and the downstream signal at the current temperature; A first determination unit configured to determine the reference sound speed at the current temperature according to the flight time difference of the target signal, the flight time of the target signal at the calibration temperature, and the specified flow rate; the flight time of the target signal at the calibration temperature is calculated according to the acquired sound speed at the calibration temperature and the flow rate at the calibration temperature; A second determination unit configured to calculate the reference flow rate corresponding to the reference sound speed at the current temperature according to the reference sound speed and the flight time difference between the upstream and downstream signals at the current temperature; determine the flight time of the target signal at the current temperature according to the reference sound speed and the reference flow rate; determine the reference signal flight time difference according to the flight time of the target signal at the current temperature and the flight time of the target signal at the calibration temperature; the flight time of the target signal at the calibration temperature is calculated according to the acquired sound speed at the calibration temperature and the flow rate at the calibration temperature; the reference signal flight time difference refers to the flight time difference between the first signal and the second signal, the first signal is the upstream signal at the calibration temperature, and the second signal is the upstream signal at the current temperature, or the first signal is the downstream signal at the calibration temperature, and the second signal is the downstream signal at the current temperature; A third determination unit configured to perform a specified operation on the reference signal flight time difference and the target signal flight time difference to obtain a first operation result; if the first operation result meets a first preset condition, determine the reference sound speed as the true sound speed at the current temperature, and determine the fluid flow rate at the current temperature according to the true sound speed; if the first operation result does not meet the first preset condition, update the reference sound speed, and return to the step of calculating the reference flow rate corresponding to the reference sound speed at the current temperature according to the reference sound speed and the flight time difference between the upstream and downstream signals at the current temperature.

6. The device according to claim 5, wherein The specified operation includes: calculating the difference between the reference signal flight time difference and the target signal flight time difference; the first preset condition includes: the absolute value of the first operation result is less than a preset threshold; the third determination unit is specifically configured to: In the case where the first operation result is greater than or equal to the preset threshold, determine whether the reference signal flight time difference is greater than the target signal flight time difference; If the reference signal flight time difference is greater than the target signal flight time difference, increase the reference sound speed by a specified value; If the reference signal flight time difference is less than the target signal flight time difference, decrease the reference sound speed by a specified value; And / or, the third determination unit is specifically configured to: Calculate the fluid flow velocity corresponding to the true sound velocity at the current temperature based on the true sound velocity and the round-trip signal flight time difference at the current temperature; And / or, the third determination unit is specifically configured to: Determine the reference flow velocity at the current temperature corresponding to the true sound velocity as the fluid flow velocity at the current temperature.

7. An ultrasonic flowmeter, characterized in that, The ultrasonic flowmeter includes: A first transducer, configured to send a first ultrasonic signal to a second transducer and receive a second ultrasonic signal sent by the second transducer; A second transducer, configured to send the second ultrasonic signal to the first transducer and receive the first ultrasonic signal sent by the first transducer; A controller, configured to execute the method according to any one of claims 1 to 4.

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