Fluid flow velocity determination method and device and ultrasonic flowmeter

Abstract

The invention provides a fluid flow velocity determination method and device and an ultrasonic flowmeter. According to the invention, the reference sound velocity at the current temperature is determined based on the obtained target signal flight time difference, the reference signal flight time difference is determined based on the reference sound velocity and the uplink and downlink signal flight time difference at the current temperature, and the target signal is further determined according to the reference signal flight time difference and the target signal flight time difference. Performing temperature compensation on the reference sound velocity to obtain a real sound velocity at the current temperature, and determining a fluid flow velocity at the current temperature according to the real sound velocity; the reference sound velocity is adjusted based on the calibrated target signal flight time difference and the reference signal flight time difference determined by the reference sound velocity, so that the reference temperature approaches the real sound velocity at the current temperature, and the fluid flow velocity at the current temperature is determined through the real sound velocity with high accuracy. The influence of temperature change on measurement accuracy is reduced, and the accuracy of fluid flow velocity measurement is improved.

Description

Technical Field

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

[0002] Ultrasonic flowmeters use the time difference of sound waves propagating in fluids to measure fluid flow rate. Since the propagation speed of ultrasound in fluids is affected by the fluid flow rate, the propagation speed in the downstream direction is faster and the propagation speed in the upstream direction is slower. Therefore, by measuring the flight time difference of ultrasound waves propagating in the downstream and upstream directions, the flow rate of the fluid can be calculated. However, in actual applications, temperature changes will also affect the propagation speed of ultrasound, thereby affecting the accuracy of fluid flow rate measurement. Summary of the invention

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

[0004] The technical solutions provided by this application are as follows: According to an embodiment of the first aspect of the present application, a method for determining a fluid flow rate is provided, the method comprising: Obtaining a target signal flight time difference; the target signal flight time difference refers to a flight time difference between an uplink signal at a specified temperature and an uplink signal at a current temperature, or a flight time difference between a downlink signal at a specified temperature and a downlink signal at a current temperature; Determine a reference speed of sound at a current temperature based on the target signal flight time difference; Determine a 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; the reference signal flight time difference refers to the flight time difference between a first signal and a second signal, the first signal is an uplink signal at a rated temperature, and the second signal refers to an uplink signal at the current temperature, or the first signal is a downlink signal at a rated temperature, and the second signal refers to a downlink signal at the current temperature; Based on the reference signal flight time difference and the target signal flight time difference, the reference sound velocity is temperature compensated to obtain a true sound velocity at a current temperature, and the fluid flow rate at the current temperature is determined according to the true sound velocity.

[0005] Optionally, determining a reference speed of sound at a current temperature based on the target signal flight time difference includes: Determining a reference sound velocity at a previous temperature according to the target signal flight time difference, the target signal flight time at a calibration temperature, and a specified flow rate; The target signal refers to an uplink signal or a downlink signal, and the flight time of the target signal at the calibration temperature is calculated based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature.

[0006] Optionally, determining the reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature includes: The reference flow velocity corresponding to the reference sound velocity at the current temperature is calculated according to the reference sound velocity and the flight time difference of the uplink and downlink signals at the current temperature; Determine the flight time of a target signal at a current temperature according to the reference sound velocity and the reference flow velocity, wherein the target signal refers to an uplink signal or a downlink signal; The reference signal flight time difference is determined based on 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 based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature.

[0007] 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 a true sound speed at a current temperature includes: Performing 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 satisfies the first preset condition, the reference sound speed is determined as the actual sound speed at the current temperature; If the first calculation result does not meet the first preset condition, the reference sound speed is updated, and the process returns to the step of determining the reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature.

[0008] 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, including: When the first operation result is greater than or equal to the preset threshold, determining 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, increasing the reference sound speed by a specified value; If the reference signal flight time difference is smaller than the target signal flight time difference, the reference sound speed is reduced by a specified value.

[0009] Optionally, determining the fluid flow rate at the current temperature according to the true sound speed includes: The fluid flow rate corresponding to the true sound speed at the current temperature is calculated according to the true sound speed and the flight time difference of the uplink and downlink signals at the current temperature.

[0010] Optionally, determining the fluid flow rate at the current temperature according to the true sound speed includes: The reference flow rate at the current temperature corresponding to the true sound speed is determined as the fluid flow rate at the current temperature.

[0011] According to an embodiment of the second aspect of the present application, a fluid flow rate determination device is provided, the device comprising: An obtaining unit, used to obtain a target signal flight time difference; the target signal flight time difference refers to a flight time difference between an uplink signal at a specified temperature and an uplink signal at a current temperature, or a flight time difference between a downlink signal at a specified temperature and a downlink signal at a current temperature; A first determining unit, configured to determine a reference sound speed at a current temperature based on the target signal flight time difference; A second determination unit is used to determine a reference signal flight time difference based on the reference sound speed and the flight time difference of the uplink and downlink signals at the current 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 uplink signal at the calibration temperature, and the second signal refers to the uplink signal at the current temperature, or the first signal is the downlink signal at the calibration temperature, and the second signal refers to the downlink signal at the current temperature; The third determination unit is used to perform temperature compensation on the reference sound speed based on the reference signal flight time difference and the target signal flight time difference to obtain a true sound speed at a current temperature, and determine the fluid flow rate at the current temperature according to the true sound speed.

[0012] Optionally, the first determining unit is specifically configured to: Determining a reference sound velocity at a previous temperature according to the target signal flight time difference, the target signal flight time at a calibration temperature, and a specified flow rate; Wherein, the target signal refers to an uplink signal or a downlink signal, and the flight time of the target signal at the calibration temperature is calculated based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature; And / or, the second determining unit is specifically configured to: The reference flow velocity corresponding to the reference sound velocity at the current temperature is calculated according to the reference sound velocity and the flight time difference of the uplink and downlink signals at the current temperature; Determine the flight time of a target signal at a current temperature according to the reference sound velocity and the reference flow velocity, wherein the target signal refers to an uplink signal or a downlink signal; 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 based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature; And / or, the third determining unit is specifically configured to: Performing 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 satisfies the first preset condition, the reference sound speed is determined as the actual sound speed at the current temperature; If the first calculation result does not meet the first preset condition, the reference sound speed is updated, and the step of determining the reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature is returned; 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 is specifically used to: When the first operation result is greater than or equal to the preset threshold, determining 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, increasing the reference sound speed by a specified value; If the reference signal flight time difference is less than the target signal flight time difference, reducing the reference sound speed by a specified value; And / or, the third determining unit is specifically configured to: The fluid flow velocity corresponding to the true sound velocity at the current temperature is calculated according to the true sound velocity and the flight time difference of the uplink and downlink signals at the current temperature; And / or, the third determining unit is specifically configured to: The reference flow rate at the current temperature corresponding to the true sound speed is determined as the fluid flow rate at the current temperature.

[0013] According to an embodiment of the third aspect of the present application, an ultrasonic flow meter is provided, the ultrasonic flow meter comprising: 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, used to execute the method described in the first aspect.

[0014] It can be seen from the above technical scheme that the present 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 uplink and downlink signal flight time difference at the current temperature, and further performs temperature compensation on 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, and then determines the fluid flow rate at the current temperature based on 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 true sound speed with higher accuracy, thereby reducing the influence of temperature changes on the measurement accuracy and improving the accuracy of fluid flow rate measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0016] Figure 1 A schematic diagram of a scenario for ultrasonic flow meter time difference measurement provided in an embodiment of the present application; Figure 2 A flow chart of a method for determining a fluid flow rate provided in an embodiment of the present application; Figure 3 A schematic diagram of a specific method for determining a fluid flow rate provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of an ultrasonic flow meter provided in an embodiment of the present application; Figure 5 A structural diagram of a fluid flow rate determination device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0017] 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 purposes, features and advantages of the embodiments of the present application more obvious and understandable, the technical solutions in the embodiments of the present application are further described in detail below in conjunction with the accompanying drawings.

[0018] Ultrasonic flow meters usually use the time difference of sound waves propagating in the fluid to measure the flow rate of the fluid. Since the propagation speed of ultrasonic waves in the fluid will be affected by the flow rate of the fluid, the propagation speed in the downstream direction will be accelerated, and the propagation speed in the upstream direction will be slowed down. Therefore, by measuring the flight time difference of ultrasonic waves propagating in the downstream and upstream directions, the flow rate of the fluid can be calculated.

[0019] Please refer to Figure 1 , Figure 1 A schematic diagram of a scenario for ultrasonic flow metering using the time difference method provided in an embodiment of the present application.

[0020] In this embodiment, the ultrasonic flow meter may include a transducer 1, a transducer 2, and a controller ( Figure 1 not shown).

[0021] like Figure 1 As shown, there is flowing fluid in the pipeline, and transducer 1 and transducer 2, which are transmitter and receiver respectively, are deployed at two positions outside the pipeline.

[0022] In this embodiment, the fluid in the pipeline flows from the right to the left. The following is an introduction to some parameters shown in the figure: Wherein, D represents the diameter of the pipe; L represents the length of the sound wave transmission path, that is, the length of the dotted line connecting transducer 1 and transducer 2; Φ represents the angle between the sound wave transmission path and the pipe; v represents the fluid flow rate.

[0023] It is easy to understand that the sound wave flight time from transducer 1 to transducer 2 (recorded as the uplink signal flight time) is: ,but .in, represents the acoustic wave flight time from transducer 1 to transducer 2, c Represents the speed of sound in the medium (fluid).

[0024] The acoustic wave flight time from transducer 2 to transducer 1 (recorded as the downlink signal flight time): but .in, Represents the flight time of the sound wave from transducer 2 to transducer 1.

[0025] in, , uplink and downlink flight time difference .

[0026] In this embodiment, the direct measurement of the flight time is adopted. and The measurement error is relatively large, so the flight time difference is generally used to characterize and calculate the flow velocity of the fluid, that is:

[0027] From the above formula, we can know that the speed of sound Directly affects flow rate The calculation result can be used to calculate the current fluid flow rate through the sound speed c based on the above formula. However, in practical applications, temperature changes will affect the propagation speed of ultrasound, that is, the propagation speed of ultrasound in the same fluid is different at different temperatures.

[0028] Taking into account the influence of temperature on the propagation speed of ultrasound, the propagation speed of ultrasound in the fluid, that is, the speed of sound It can be expressed as:

[0029] in, is the reference temperature The ultrasonic wave propagation speed under is the temperature coefficient, is the current temperature.

[0030] In this case, if the current fluid flow rate is determined directly by the sound velocity at the calibration temperature without considering the influence of temperature changes, the accuracy of the fluid flow rate measurement at the current temperature will be affected.

[0031] Therefore, it is an important measure to ensure the measurement accuracy of the ultrasonic time-difference flowmeter to compensate for the temperature drift of the sound velocity and further determine the fluid flow rate at the current temperature through the sound velocity after temperature drift compensation.

[0032] Based on this, the present application proposes a method for determining fluid flow rate to improve the measurement accuracy of a time-difference flowmeter.

[0033] Please refer to Figure 2 , Figure 2 A flowchart of a method for determining fluid flow rate provided in an embodiment of the present application.

[0034] like Figure 2 As shown, the method may include the following steps: Step 201, obtaining the target signal flight time difference.

[0035] In this embodiment, the target signal flight time difference refers to the flight time difference between the uplink signal at a rated temperature and the uplink signal at a current temperature, or the flight time difference between the downlink signal at a rated temperature and the downlink signal at a current temperature.

[0036] For example, the signal obtained by propagating the sound wave for a specified distance 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) can be recorded as an uplink signal, and the signal obtained by propagating the sound wave for a specified distance in the opposite direction of the flow direction of the fluid (i.e., the angle between the sound wave propagation direction and the fluid flow direction is greater than 90 degrees) can be recorded as a downlink signal.

[0037] In this embodiment, the specific steps of obtaining the target signal flight time difference may include: The target signal at the calibration temperature and the target signal at the current temperature are obtained, and the target signal at the calibration temperature and the target signal at the current temperature are input into a cross-correlation algorithm to obtain the target signal flight time difference between the target signal at the calibration temperature and the target signal at the current temperature through the cross-correlation algorithm.

[0038] The target signal refers to an uplink signal or a downlink signal. The specific examples below are described by taking the target signal as an uplink signal. The processing method of the downlink signal is similar to that of the uplink signal and will not be described separately later.

[0039] In this embodiment, a method for obtaining relevant parameters at the calibration temperature will be described in detail below and will not be repeated here.

[0040] At this point, the description of step 201 ends, and step 202 is executed next.

[0041] Step 202: Determine a reference speed of sound at a current temperature based on the target signal flight time difference.

[0042] In this embodiment, after the target signal flight time difference is obtained in step 201, the reference sound speed at the current temperature can be obtained based on the target signal flight time difference.

[0043] Specifically, a specific method for determining a reference sound speed at a current temperature based on a target signal flight time difference may include: Determine a reference sound velocity at a previous temperature based on the target signal flight time difference, the target signal flight time at the calibration temperature, and the specified flow rate; The target signal refers to an uplink signal or a downlink signal, and the flight time of the target signal at the calibration temperature is calculated based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature.

[0044] In this embodiment, the speed of sound at the calibration temperature and the flow velocity at the calibration temperature may be first obtained, and the target signal flight time at the calibration temperature may be calculated according to the speed of sound at the calibration temperature and the flow velocity at the calibration temperature.

[0045] The following first describes the method for obtaining the sound velocity and flow velocity at the calibration temperature.

[0046] First, obtain the sound velocity measured at the calibration temperature , and determine the flight time difference of the uplink and downlink signals at the calibration temperature based on the cross-correlation algorithm , and then through the above-mentioned relationship between the speed of sound, the flight time difference of the uplink and downlink signals and the flow velocity:

[0047] Will as well as Substitute into the flow rate at the calibration temperature .

[0048] The flight time difference of uplink and downlink signals at the calibration temperature is determined by the cross-correlation algorithm. The process is a common method in the related art and will not be described in detail here.

[0049] Similarly, you can first obtain the flow rate measured at the calibration temperature , and determine the flight time difference of the uplink and downlink signals at the calibration temperature based on the cross-correlation algorithm , and then through the above relationship as well as Substitute into the sound velocity at the calibration temperature , this application does not impose any restrictions on this.

[0050] Determine the speed of sound at the calibration temperature and flow rate Afterwards, the target signal flight time at the calibration temperature can be further calculated according to the sound velocity at the calibration temperature and the flow velocity at the calibration temperature.

[0051] Specifically, taking the target signal as the uplink signal as an example, the sound velocity at the calibration temperature can be and the flow rate at the nominal temperature , calculate the target signal flight time at the calibration temperature (uplink signal flight time at the calibration temperature):

[0052] in, To calibrate the flight time of the target signal under temperature, the flight time is not directly measured but calculated based on the relationship between the flight distance and the flight speed.

[0053] Further, after determining the target signal flight time at the calibration temperature, the reference sound velocity at the previous temperature may be determined according to the target signal flight time difference, the target signal flight time at the calibration temperature, and the specified flow rate.

[0054] Specifically, still taking the target signal as an uplink signal as an example, since:

[0055] in, is the target signal flight time difference determined in step 201, is the flight time of the target signal (uplink signal) at the current temperature, is the flight time of the target signal (uplink signal) at the calibration temperature, c is the speed of sound at the current temperature, and v is the flow velocity at the current temperature.

[0056] After equivalent transformation according to the above formula, we can get:

[0057] That is, the relationship between the sound velocity and the flow velocity at the current temperature is obtained.

[0058] At this time, you can preset a specified flow rate, such as the specified flow rate , put the specified flow rate into the above formula to calculate the reference sound speed at the current temperature .

[0059] In this embodiment, the specified flow rate can be any preset value, and the present application does not limit this. The reference sound velocity at the current temperature determined according to the specified flow rate is It is an estimated value, and the value of the reference sound speed will be further adjusted according to subsequent calculation results so that the reference sound speed is close to the actual sound speed at the current temperature.

[0060] At this point, the description of step 202 ends, and step 203 is executed next.

[0061] Step 203: Determine a reference signal flight time difference based on a reference sound speed and the flight time difference of the uplink and downlink signals at a current temperature.

[0062] 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 refers to the uplink signal at the current temperature, or the first signal is the downlink signal at the calibration temperature, and the second signal refers to the downlink signal at the current temperature.

[0063] 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 of the uplink and downlink signals at the current temperature. The 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.

[0064] Exemplarily, based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature, a specific method for determining the reference signal flight time difference may include: The reference flow velocity corresponding to the reference sound velocity at the current temperature is calculated based on the reference sound velocity and the flight time difference of the uplink and downlink signals at the current temperature; Determine the flight time of the target signal at the current temperature according to the reference sound velocity and the reference flow velocity, the target signal refers to the uplink signal or the downlink signal; The reference signal flight time difference is determined based on 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 based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature.

[0065] In this embodiment, the flight time difference of the uplink and downlink signals at the current temperature can be obtained by a cross-correlation algorithm, which will not be described in detail here.

[0066] After obtaining the flight time difference of the uplink and downlink signals at the current temperature, the reference flow velocity corresponding to the reference sound velocity at the current temperature can be calculated according to the reference sound velocity and the flight time difference of the uplink and downlink signals at the current temperature.

[0067] Specifically, the reference sound speed And the flight time difference of uplink and downlink signals at the current temperature Substitute the above relationship between the speed of sound, the flight time difference between the uplink and downlink signals, and the flow velocity:

[0068] To obtain the reference speed of sound Corresponding reference flow rate .

[0069] Furthermore, the target signal flight time at the current temperature may be determined according to the reference sound velocity and the reference flow velocity.

[0070] Taking the target signal as the uplink signal as an example, the target signal flight time at the current temperature is: ,in, is the reference sound speed at the current temperature, is the reference flow velocity corresponding to the above reference sound velocity at the current temperature.

[0071] After determining the target signal flight time at the current temperature, the reference signal flight time difference may be determined according to the target signal flight time at the current temperature and the target signal flight time at the calibration temperature.

[0072] Specifically, taking the target signal as an uplink signal as an example, the reference signal flight time difference The calculation method is:

[0073] in, is the reference signal flight time difference (i.e., the difference between the uplink signal flight time at the current temperature calculated based on the reference sound velocity and the reference flow velocity and the uplink signal flight time at the obtained calibration temperature).

[0074] At this point, the description of step 203 ends, and step 204 is executed next.

[0075] Step 204 , based on the reference signal flight time difference and the target signal flight time difference, the reference sound velocity is temperature compensated to obtain the real sound velocity at the current temperature, and the fluid flow rate at the current temperature is determined according to the real sound velocity.

[0076] In this embodiment, the reference signal flight time difference determined in step 203 is actually the difference between the uplink signal flight time at the calibration temperature and the current temperature calculated based on the reference sound speed, or the difference between the downlink signal flight time at the calibration temperature and the current temperature. Further, the reference signal flight time difference (calculated value) can be compared with the target signal flight time difference (accurate value) determined in step 201 to adjust the reference sound speed according to the error value between the two, so that the reference signal flight time difference gradually approaches the target signal flight time difference, that is, the reference sound speed gradually approaches the actual sound speed at the current temperature, so as to achieve temperature compensation for the sound speed.

[0077] Exemplarily, based on the reference signal flight time difference and the target signal flight time difference, the reference sound speed is temperature compensated to obtain the actual sound speed at the current temperature. The specific method includes: Performing 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 satisfies the first preset condition, the reference sound speed is determined as the actual sound speed at the current temperature; If the first operation result does not meet the first preset condition, the reference sound speed is updated, and the process returns to the step of determining the reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature.

[0078] As an embodiment, a specified operation is performed on the reference signal flight time difference and the target signal flight time difference to obtain a first operation result, which can be the difference between the reference signal flight time difference and the target signal flight time difference, or the relative error, percentage error, etc. between the reference signal flight time difference and the target signal flight time difference. The present application does not impose any restrictions on this.

[0079] Taking the designated operation of calculating the difference between the reference signal flight time difference and the target signal flight time difference as an example, the corresponding first preset condition may be that the absolute value of the first operation result is less than a preset threshold.

[0080] When the absolute value of the difference between the reference signal flight time difference and the target signal flight time difference is less than a preset threshold, it indicates that the error between the reference signal flight time difference and the target signal flight time difference is extremely small. At this time, the current reference sound speed can be determined as the true sound speed at the current temperature.

[0081] In this embodiment, the size of the preset threshold can be determined according to the resolution of the reference signal flight time difference and the target signal flight time difference.

[0082] When the absolute value of the difference between the reference signal flight time difference and the target signal flight time difference is greater than or equal to a preset threshold, it indicates that the error between the reference signal flight time difference and the target signal flight time difference is large. At this time, the reference sound speed can be adjusted and the step of determining the reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature is returned to make the reference sound speed close to the actual sound speed at the current temperature.

[0083] The specific adjustment methods can be: 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, the reference sound speed is increased by a specified value; If the reference signal flight time difference is less than the target signal flight time difference, the reference sound speed is reduced by a specified value.

[0084] In this embodiment, the size of the specified value can be set according to the size of the difference between the reference signal flight time difference and the target signal flight time difference. For example, the size of the specified value is positively correlated with the size of the difference between the reference signal flight time difference and the target signal flight time difference.

[0085] As an embodiment, the size of the specified value can also be traversed using a binary search method, which is not limited in this application.

[0086] For example, the reference signal flight time difference and the target signal flight time difference are calculated according to the following formula:

[0087] in, is the reference signal flight time difference, It refers to the target signal flight time difference, Refers to the preset threshold.

[0088] When the reference signal flight time difference and the target signal flight time difference meet the above conditions, the reference sound speed is increased or decreased by a specified value, the reference sound speed is updated, and the step of determining the reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature is returned until the absolute value of the difference between the reference signal flight time difference and the target signal flight time difference is less than the above preset threshold.

[0089] In this embodiment, it is easy to understand that The reference signal flight time difference is determined by the reference sound speed and the reference flow velocity. Since the reference sound speed and the reference flow velocity are not accurate 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 the present application is to adjust the reference sound speed so that the reference signal flight time difference is close to the target signal flight time difference, so that the reference sound speed is close to the actual sound speed at the current temperature, and the reference flow velocity is close to the actual flow velocity at the current temperature.

[0090] In this embodiment, after adjusting the reference sound velocity and determining the real sound velocity at the current temperature, the fluid flow velocity at the current temperature, that is, the real flow velocity at the current temperature, can be determined based on the real sound velocity. Specifically, the real sound velocity and the flight time difference of the uplink and downlink signals at the current temperature can be substituted into the formula to obtain the real flow velocity at the current temperature:

[0091] in, is the actual flow rate at the current temperature, is the true speed of sound at the current temperature, It is the flight time difference of uplink and downlink signals at the current temperature.

[0092] As an embodiment, in fact, in the process of determining the true sound speed, the true flow velocity corresponding to the true sound speed has been determined, that is, before the reference sound speed is used as the true sound speed, the reference flow velocity corresponding to the reference sound speed is determined, that is, the true flow velocity corresponding to the true sound speed.

[0093] This concludes the description of step 204.

[0094] This concludes Figure 2 Description of the flow chart of the medium fluid velocity method.

[0095] The present application determines a reference sound speed at the current temperature based on the obtained target signal flight time difference, and determines a reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature, and further performs temperature compensation on the reference sound speed based on the reference signal flight time difference and the target signal flight time difference to obtain a true sound speed at the current temperature, and then determines the fluid flow rate at the current temperature based on 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 true sound speed with higher accuracy, thereby reducing the influence of temperature changes on measurement accuracy, and improving the accuracy of fluid flow rate measurement, so as to achieve high-precision fluid flow rate measurement without measuring temperature.

[0096] Below through Figure 3 The method proposed in this application is described.

[0097] Please refer to Figure 3 , Figure 3 A schematic diagram of a specific method for determining a fluid flow rate provided in an embodiment of the present application.

[0098] like Figure 3 As shown, Figure 1 Taking the scenario shown in as an example, the fluid flow rate determination method proposed in this application may include the following steps: According to the sound velocity at the calibration temperature , the flight time difference of uplink and downlink signals at the calibration temperature is calculated by cross-correlation algorithm , and then the flow velocity at the calibration temperature can be obtained according to the relationship between the sound velocity, flow velocity and the flight time difference of the uplink and downlink signals. ; Among them, taking the target signal as the uplink signal as an example, assuming =1460m / s, =10^5ps, the angle between the fluid velocity and the direction of propagation of the sound wave of the uplink signal , the inner diameter of the pipe D is 0.1m, then =2.6379m / s.

[0099] The precise flight time of the uplink signal at the calibration temperature is calculated as a fixed constant:

[0100] Furthermore, the target signal flight time difference is obtained through the cross-correlation algorithm, that is, the flight time difference between the uplink and downlink signals at the calibration temperature and the current temperature. , and because

[0101] in, is the target signal flight time difference, is the flight time of the target signal (uplink signal) at the current temperature, is the flight time of the target signal (uplink signal) at the calibration temperature, c is the speed of sound at the current temperature, and v is the flow velocity at the current temperature.

[0102] Then, the relationship between the speed of sound and the flow rate at the current temperature can be derived:

[0103] Assuming the specified flow rate , =1000ps, calculate the reference sound speed =1461m / s; The reference speed of sound Substituting the relationship between the speed of sound, flow velocity, and the time difference between the uplink and downlink signals, assuming =10^4ps, , get the reference flow rate ;in, is the flight time difference of the uplink and downlink signals at the current temperature, which can be obtained through the cross-correlation algorithm.

[0104] According to the reference speed of sound and reference flow rate Calculate the reference signal flight time difference ; if , then the reference sound speed Increase or decrease the specified value, returning the reference sound speed Substitute the relationship between the speed of sound, the flow velocity, and the time difference between the uplink and downlink signals to calculate the reference flow velocity. For the preset threshold size, such as , the true sound speed is calculated by continuous iteration according to the threshold value (i.e., the resolution of the flight time difference). The reference flow velocity corresponding to the true sound speed is the fluid flow velocity at the current temperature.

[0105] This concludes Figure 3 Description.

[0106] Please refer to Figure 4 , Figure 4 It is a schematic structural diagram of an ultrasonic flow meter proposed in an embodiment of the present application.

[0107] like Figure 4 As shown, the ultrasonic flow meter includes: The first transducer is used to send a first ultrasonic signal to the second transducer and receive a second ultrasonic signal sent by the second transducer; The second transducer is used to send a second ultrasonic signal to the first transducer and receive the first ultrasonic signal sent by the first transducer; Controller, used to perform Figure 2 The method shown.

[0108] In this embodiment, the controller and the first transducer and the second transducer may be connected via a control bus to achieve communication, which is not limited in the present application.

[0109] The method for determining the fluid flow rate executed by the controller has been described in detail above and will not be repeated here.

[0110] This concludes Figure 4 Description of ultrasonic flow meter.

[0111] Please refer to Figure 5 , Figure 5 : is a structural diagram of a fluid flow rate determination device proposed in an embodiment of the present application. Figure 5 As shown, the device may include an obtaining unit 501, a first determining unit 502, a second determining unit 503, and a third determining unit 504. Specifically, the device includes: The obtaining unit 501 is used to obtain the target signal flight time difference; the target signal flight time difference refers to the flight time difference between the uplink signal at the rated temperature and the uplink signal at the current temperature, or the flight time difference between the downlink signal at the rated temperature and the downlink signal at the current temperature; A first determining unit 502, configured to determine a reference sound speed at a current temperature based on a target signal flight time difference; The second determination unit 503 is used to determine a reference signal flight time difference based on a reference sound speed and a flight time difference of an uplink or downlink signal at a current temperature; the reference signal flight time difference refers to a flight time difference between a first signal and a second signal, the first signal is an uplink signal at a rated temperature, and the second signal refers to an uplink signal at a current temperature, or the first signal is a downlink signal at a rated temperature, and the second signal refers to a downlink signal at a current temperature; The third determination unit 504 is used to perform temperature compensation on the reference sound speed based on the reference signal flight time difference and the target signal flight time difference to obtain the real sound speed at the current temperature, and determine the fluid flow rate at the current temperature according to the real sound speed.

[0112] Optionally, the first determining unit 502 is specifically configured to: Determine a reference sound velocity at a previous temperature based on the target signal flight time difference, the target signal flight time at the calibration temperature, and the specified flow rate; Wherein, the target signal refers to an uplink signal or a downlink signal, and the flight time of the target signal at the calibration temperature is calculated based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature; And / or, the second determining unit 503 is specifically configured to: The reference flow velocity corresponding to the reference sound velocity at the current temperature is calculated based on the reference sound velocity and the flight time difference of the uplink and downlink signals at the current temperature; Determine the flight time of the target signal at the current temperature according to the reference sound velocity and the reference flow velocity, the target signal refers to the uplink signal or the downlink signal; 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 at the calibration temperature and the flow velocity at the calibration temperature; And / or, the third determining unit 504 is specifically configured to: Performing 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 satisfies the first preset condition, the reference sound speed is determined as the actual sound speed at the current temperature; 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 flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature is returned; 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 used to: When the first operation result is greater than or equal to a preset threshold, determining 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, the reference sound speed is increased by a specified value; If the reference signal flight time difference is less than the target signal flight time difference, the reference sound speed is reduced by a specified value; And / or, the third determining unit 504 is specifically configured to: The fluid flow velocity corresponding to the true sound velocity at the current temperature is calculated based on the true sound velocity and the flight time difference of the uplink and downlink signals at the current temperature; And / or, the third determining unit 504 is specifically configured to: The reference flow rate at the current temperature corresponding to the true sound speed is determined as the fluid flow rate at the current temperature.

[0113] So far, completed Figure 5Description of a device for determining fluid flow rate.

[0114] Correspondingly, an embodiment of the present application further provides a computer-readable storage medium, on which a number of computer instructions are stored. When the computer instructions are executed, the method disclosed in the above example of the present application can be implemented.

[0115] Exemplarily, the computer-readable storage medium may be any electronic, magnetic, optical or other physical storage device that may contain or store information, such as executable instructions, data, etc. For example, the computer-readable storage medium may be: RAM (Radom Access Memory), volatile memory, non-volatile memory, flash memory, storage drive (such as hard disk drive), solid state drive, any type of storage disk (such as optical disk, DVD, etc.), or similar storage medium, or a combination thereof.

[0116] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for determining fluid flow rate, characterized in that: The method includes: Obtaining a target signal flight time difference; the target signal flight time difference refers to a flight time difference between an uplink signal at a specified temperature and an uplink signal at a current temperature, or a flight time difference between a downlink signal at a specified temperature and a downlink signal at a current temperature; Determine a reference speed of sound at a current temperature based on the target signal flight time difference; Determine a 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; the reference signal flight time difference refers to the flight time difference between a first signal and a second signal, the first signal is an uplink signal at a rated temperature, and the second signal refers to an uplink signal at the current temperature, or the first signal is a downlink signal at a rated temperature, and the second signal refers to a downlink signal at the current temperature; Based on the reference signal flight time difference and the target signal flight time difference, the reference sound velocity is temperature compensated to obtain a true sound velocity at a current temperature, and the fluid flow rate at the current temperature is determined according to the true sound velocity.

2. The method according to claim 1, characterized in that: The determining of the reference sound speed at the current temperature based on the target signal flight time difference comprises: Determining a reference sound velocity at a previous temperature according to the target signal flight time difference, the target signal flight time at a calibration temperature, and a specified flow rate; The target signal refers to an uplink signal or a downlink signal, and the flight time of the target signal at the calibration temperature is calculated based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature.

3. The method according to claim 1, characterized in that The determining of the reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature includes: The reference flow velocity corresponding to the reference sound velocity at the current temperature is calculated according to the reference sound velocity and the flight time difference of the uplink and downlink signals at the current temperature; Determine the flight time of a target signal at a current temperature according to the reference sound velocity and the reference flow velocity, wherein the target signal refers to an uplink signal or a downlink signal; The reference signal flight time difference is determined based on 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 based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature.

4. The method according to claim 3, characterized in that: The temperature compensation of the reference speed of sound based on the reference signal flight time difference and the target signal flight time difference to obtain the real speed of sound at the current temperature includes: Performing 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 satisfies the first preset condition, the reference sound speed is determined as the actual sound speed at the current temperature; If the first calculation result does not meet the first preset condition, the reference sound speed is updated, and the process returns to the step of determining the reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature.

5. The method according to claim 4, characterized in that The designated 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, the reference sound speed is updated, including: When the first operation result is greater than or equal to the preset threshold, determining 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, increasing the reference sound speed by a specified value; If the reference signal flight time difference is smaller than the target signal flight time difference, the reference sound speed is reduced by a specified value.

6. The method according to claim 1, characterized in that The determining the fluid flow rate at the current temperature according to the true sound speed comprises: The fluid flow rate corresponding to the true sound speed at the current temperature is calculated according to the true sound speed and the flight time difference of the uplink and downlink signals at the current temperature.

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

8. A fluid flow rate determination device, characterized in that: The device includes: An obtaining unit, used to obtain a target signal flight time difference; the target signal flight time difference refers to a flight time difference between an uplink signal at a specified temperature and an uplink signal at a current temperature, or a flight time difference between a downlink signal at a specified temperature and a downlink signal at a current temperature; A first determining unit, configured to determine a reference sound speed at a current temperature based on the target signal flight time difference; A second determination unit is used to determine a reference signal flight time difference based on the reference sound speed and the flight time difference of the uplink and downlink signals at the current 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 uplink signal at the calibration temperature, and the second signal refers to the uplink signal at the current temperature, or the first signal is the downlink signal at the calibration temperature, and the second signal refers to the downlink signal at the current temperature; The third determination unit is used to perform temperature compensation on the reference sound speed based on the reference signal flight time difference and the target signal flight time difference to obtain a true sound speed at a current temperature, and determine the fluid flow rate at the current temperature according to the true sound speed.

9. The device according to claim 8, characterized in that The first determining unit is specifically configured to: Determining a reference sound velocity at a previous temperature according to the target signal flight time difference, the target signal flight time at a calibration temperature, and a specified flow rate; Wherein, the target signal refers to an uplink signal or a downlink signal, and the flight time of the target signal at the calibration temperature is calculated based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature; And / or, the second determining unit is specifically configured to: The reference flow velocity corresponding to the reference sound velocity at the current temperature is calculated according to the reference sound velocity and the flight time difference of the uplink and downlink signals at the current temperature; Determine the flight time of a target signal at a current temperature according to the reference sound velocity and the reference flow velocity, wherein the target signal refers to an uplink signal or a downlink signal; 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 based on the obtained sound velocity at the calibration temperature and the flow velocity at the calibration temperature; And / or, the third determining unit is specifically configured to: Performing 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 satisfies the first preset condition, the reference sound speed is determined as the actual sound speed at the current temperature; If the first calculation result does not meet the first preset condition, the reference sound speed is updated, and the step of determining the reference signal flight time difference based on the reference sound speed and the uplink and downlink signal flight time difference at the current temperature is returned; 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 is specifically used to: When the first operation result is greater than or equal to the preset threshold, determining 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, increasing the reference sound speed by a specified value; If the reference signal flight time difference is less than the target signal flight time difference, reducing the reference sound speed by a specified value; And / or, the third determining unit is specifically configured to: The fluid flow velocity corresponding to the true sound velocity at the current temperature is calculated according to the true sound velocity and the flight time difference of the uplink and downlink signals at the current temperature; And / or, the third determining unit is specifically configured to: The reference flow rate at the current temperature corresponding to the true sound speed is determined as the fluid flow rate at the current temperature.

10. An ultrasonic flow meter, characterized in that: The ultrasonic flow meter comprises: 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 for executing the method according to any one of claims 1 to 7.

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