阅读说明：本技术 套管装置超声波实验装置及其实验方法 (Ultrasonic experimental device and method for casing device ) 是由 魏新宇 孙奥迪 王鹏飞 高永新 于 2019-09-24 设计创作，主要内容包括：本发明公开了一种套管装置超声波实验装置及其实验方法,该装置包括高频换能器、低频换能器、同侧接收器、对侧接收器、放大器和信号处理系统；本发明提供了套管装置复杂流动超声波测量的实验装置以及实验方法；本发明能够在不破坏套管装置连续流动的条件下测量管内不同流动状态的流速,并为后续高温管道的测量提供设计思路。(The invention discloses a sleeve device ultrasonic wave experimental device and an experimental method thereof, wherein the device comprises a high-frequency transducer, a low-frequency transducer, a receiver on the same side, a receiver on the opposite side, an amplifier and a signal processing system; the invention provides an experimental device and an experimental method for complex flow ultrasonic measurement of a sleeve device; the invention can measure the flow velocity of different flowing states in the pipe under the condition of not damaging the continuous flow of the casing pipe device, and provides a design idea for the subsequent measurement of the high-temperature pipeline.)

1. The utility model provides a sleeve pipe device ultrasonic wave experimental apparatus which characterized in that: the different characteristics of high-frequency and low-frequency sound waves are utilized, namely, high-frequency sound wave signals are strong and easy to reflect, and low-frequency sound waves are strong in penetrability;

the ultrasonic experimental device of the sleeve device comprises a high-frequency transducer (2), a low-frequency transducer (2'), a receiver (3) on the same side, a receiver (1) on the opposite side, an amplifier (4) and a signal processing system (5); wherein the high-frequency transducer (2) and the low-frequency transducer (2 ') are arranged at the same position of the casing device, the high-frequency transducer (2) and the low-frequency transducer (2 ') and the receiver (3) at the same side are arranged on the same bus of the casing device, the opposite side receiver (1) is arranged at the opposite side of the low-frequency transducer (2 '), namely the connecting line of the axis of the low-frequency transducer (2 ') and the casing device, and the connecting line of the opposite side receiver (1) and the casing device form an included angle of 180 degrees, the receiver (3) at the same side and the receiver (1) at the opposite side are simultaneously arranged at the upstream position or the downstream position of the high-frequency transducer (2) and the low-frequency transducer (2 '), the high-frequency transducer (2) and the axis of the opposite side receiver (1) and the axis of the casing device form an included angle of 45; the high-frequency transducer (2) transmits a high-frequency signal, the high-frequency signal reaches the outer wall of the inner tube of the sleeve device, is reflected and is finally received by the receiver (3) at the same side; the low-frequency transducer (2') transmits low-frequency signals, and the low-frequency signals are received by the opposite side receiver (1) through outer layer circulation of the sleeve device, the wall of the inner pipe, fluid in the inner pipe, the wall of the inner pipe and the outer layer circulation; the high-frequency transducer (2), the low-frequency transducer (2'), the receiver (3) on the same side and the receiver (1) on the opposite side are all connected with the input end of the amplifier (4), and the output end of the amplifier (4) is connected with the signal processing system (5).

2. The ultrasonic testing device of the casing device according to claim 1, wherein: the high-frequency signal emitted by the high-frequency transducer (2) is a frequency band with good reflectivity, and the frequency of the high-frequency signal is not lower than 100 kHz.

3. The ultrasonic testing device of the casing device according to claim 1, wherein: the low-frequency signal emitted by the low-frequency transducer (2') is a frequency band with good penetrability, and the signal frequency is not lower than 20 kHz.

4. The ultrasonic testing device of the casing device according to claim 1, wherein: the same-side receiver (3) can be used as a high-frequency transducer to transmit high-frequency signals, the high-frequency signals reach the outer wall of an inner tube of the sleeve device and are reflected, and finally the signals are received by the high-frequency transducer (2), so that the accuracy of the ultrasonic experimental device of the sleeve device is improved, and the flow velocity of the fluid is calculated by respectively calculating the time difference of the forward flow and the reverse flow of the acoustic fluid.

5. The ultrasonic testing device of the casing device according to claim 1, wherein: the opposite side receiver (1) is used as a low-frequency transducer to transmit low-frequency signals at the same time, and the low-frequency signals are finally received by the low-frequency transducer (2') through outer circulation of the casing device, the wall of the inner pipe, fluid in the inner pipe, the wall of the inner pipe and the outer circulation, so that the accuracy of the ultrasonic experimental device of the casing device is improved, and the time difference of forward flow and backward flow of sound wave fluid is respectively calculated to calculate the flow rate of the fluid.

6. The experimental method of the ultrasonic experimental device of the casing device according to claim 1, wherein: the characteristics of strong and easy reflection of high-frequency sound wave signals and strong penetrability of low-frequency sound waves are utilized, and the synchronous signals are adopted to analyze the complex flow of the sleeve device; high-frequency signals and low-frequency signals are sent out simultaneously, the high-frequency signals are reflected on the outer wall of the inner pipe, the reflected signals are received by the receiver (3) on the same side, and the low-frequency signals penetrate through the inner pipe wall and are finally received by the receiver (1) on the opposite side through outer layer circulation, the inner pipe wall, fluid in the inner pipe, the inner pipe wall and the outer layer circulation; firstly, the circulation flow, namely the flow speed of the fluid between the inner pipe and the outer pipe is calculated according to the time difference between the sending and receiving of the high-frequency signal, and secondly, the flow in the inner pipe is calculated by combining the circulation flow speed fed back by the high-frequency signal and the time difference between the sending and receiving of the low-frequency signal.

7. The experimental method according to claim 6, characterized in that: before the test starts, calibrating the experimental device, detecting the precision of the receiver and detecting the stability of the signal processing system; the experimental method specifically comprises the following steps:

s1, adjusting the power of the high-frequency transducer (2) and the low-frequency transducer (2'), observing received signals of the receiver (3) on the same side and the receiver (1) on the opposite side, and ensuring that the receiver can receive clearer signals due to large signal-to-noise ratio under the selected working power;

s2, calibrating the flow measured by the high-frequency transducer (2) and the receiver (3) on the same side, giving a known rated flow, and calculating the measured flow through the time difference between the high-frequency signal sent by the high-frequency transducer (2) and the high-frequency signal received by the receiver (3) on the same side; setting a correction coefficient according to the ratio of rated flow to measured flow, and completing the flow calibration on the casing device;

s3, calibrating the low-frequency transducer (2 ') -measuring the flow rate of the opposite side receiver (1), and calculating the measured flow rate by the time difference between the low-frequency signal emitted by the low-frequency transducer (2') and the low-frequency signal received by the opposite side receiver (1) given the known rated flow rate; setting a correction coefficient according to the ratio of rated flow to measured flow, wherein the high-frequency signal gives the influence of circulation flow on the sound wave signal, so that the flow calibration of the low-frequency signal is completed on a single circular tube;

s4, calculating the flow of two different states in the sleeve device: the amplifier (4) respectively amplifies the received signals of the high-frequency transducer (2), the low-frequency transducer (2'), the receiver (3) on the same side and the receiver (1) on the opposite side and transmits the amplified signals to the signal processing system (5), and after the signal processing system (5) receives the signals transmitted by the amplifier (4), the flow speed of the circulating fluid is firstly solved through the transmission time difference of the high-frequency signals, and the flow of the circulating fluid is calculated; calculating equivalent flow velocity through low-frequency signal transmission time difference, wherein the transmission time difference of the low-frequency signal comprises three parts: the first part is the propagation of low-frequency signals in the circulating fluid, the second part is the propagation of low-frequency signals in the pipe wall of the inner pipe, and the third part is the propagation of low-frequency signals in the fluid in the inner pipe; the propagation time difference of sound in the circulating fluid is calculated through a high-frequency signal, the time of sound propagation in metal on a pipe wall is constant, so that the flow in the inner pipe can be solved, and the flow of two flow states in the casing device can be obtained through integrating the time, wherein the specific calculation method comprises the following steps:

D₁，D₂outer and inner diameters of the outer tube, d₁，d₂The outer diameter and the inner diameter of the inner circular tube, alpha is the included angle between the axis of the high-frequency transducer and the low-frequency transducer and the axis of the receiver and the sleeve device on the same side, and L is the included angle between the axis of the receiver and the axis of the sleeve device on the same side₁Distance between the high-frequency transducer and the low-frequency transducer and the receiver on the same side, L₂Is the distance, S, between the high and low frequency transducers and the contralateral receiver₁To reflect the signal, S₂Penetration signal, c is sound velocity, u is flow velocity of the fluid; wherein high frequency sound wave is reflected at the outer wall of the inner tube to reflect a signal S₁Received by the receiver on the same side, the time difference between the transmitted and received signals is expressed as:

in fact, the transducer is also a receiver, and the method of final averaging of the bidirectional signals is usually adopted to reduce errors; obtaining the total transmission time T of the low-frequency signal by measurement_t(ii) a The total transmission time includes three parts: the first part is the time T taken for the low frequency signal to travel in the circulating fluid₁', the second part is the time T' taken for the low frequency signal to travel on the metal pipe wall, and the third part is the time T taken for the low frequency signal to travel in the fluid in the inner pipe₂Namely:

T_t＝T₁'+T₂+T' (2)

because the thickness of the pipe wall is much smaller compared to the diameter of the whole channel, and in addition, the propagation speed of sound in the solid is much greater than that in the fluid, the time T' for sound to travel on the metal pipe is very small and is ignored in the calculation; and T₁' approximately equal to T₁(ii) a Reflected signal S₁And a transmission pathPenetration signal S₂The distance traveled and the resulting effect in the sheath fluid are the same, assuming that the velocity of the fluid does not change during the minute time period of the signal being transmitted, then:

T₁＝T₁' (3)

based on the above conclusions, equation (2) reduces to:

T₂＝T_t-T₁ (4)

wherein T is_tAnd T₁The time difference between the low-frequency signal received by the opposite side receiver (1) and the low-frequency signal sent by the low-frequency transducer (2') and the time difference between the high-frequency signal received by the same side receiver (3) and the high-frequency signal sent by the high-frequency transducer (2) are known quantities, so that T is obtained₂A value of (d); t is₂Expressed as:

the flow velocity u in the inner tube is simplified by substituting equation (4) into equation (5)_hThe expression of (a) is:

from the expression, u can be seen_hCalculating according to the measured value; it is noted that the sound velocity c used in the formula is the same, and in practical applications should be replaced by the sound velocity of sound at the material.

Technical Field

The invention belongs to the field of measurement and control, and particularly relates to an ultrasonic experimental device and an ultrasonic experimental method for a casing device, which are used for measuring the flow of complex flow of the casing device.

Background

The double-pipe heat exchanger is a heat exchanger which is most widely applied to the petrochemical production at present, and the structural schematic diagram of the heat exchanger is shown in figure 3, wherein the lower corner mark l in the figure represents a low-temperature working medium, h represents a high-temperature working medium, the lower corner mark in represents an inlet, and out represents a high-temperature working mediumT denotes the thermodynamic temperature, u denotes the velocity of the fluid, Q_eIndicating the amount of heat exchange. For a given inlet temperature and heat exchange area, the heat exchange coefficient can be calculated as long as the flow speed of the working medium is known, and then the heat exchange quantity and the outlet temperature are calculated. The temperature at the outlet is therefore inseparable from the velocity of the fluid. Control of the flow rate to the sleeve is directly related to heat exchange efficiency and can be used to detect cracking problems inside the sleeve. The accurate measurement of the flow of the sleeve device can not improve the energy utilization rate and can effectively protect the safe operation of the heat exchange equipment.

According to the current measuring method of the flowmeter, the following 4 categories can be roughly classified: differential pressure type flowmeter, speed type flowmeter, positive displacement flowmeter, and quality type flowmeter. The ultrasonic flowmeter belongs to a velocity type flowmeter, and compared with other flowmeters, the ultrasonic flowmeter calculates the flow velocity of fluid by measuring the difference of sound velocities of ultrasonic waves propagating along the forward direction and the reverse direction of airflow, and belongs to a non-contact flowmeter, so compared with other flowmeters, the ultrasonic flowmeter has the following 6 characteristics: (1) bidirectional flow can be measured; (2) the flow rate of turbulent fluid (rivers, open channels and the like) can be measured; (3) the device is suitable for different fluids with different pipe diameters; (4) no interference to flow and small pressure loss; (5) high temperature, corrosive fluids can be measured; (6) the multi-channel measurement can improve the precision and reduce the influence of unstable flow, and the transducer and the later software can effectively correct the flow parameters in the pipeline. This also provides the possibility of accounting for the complex flow measurements of the cannula device.

Because two flows (forward flow and reverse flow) in different states exist in the casing device, the current ultrasonic flowmeter cannot measure the flow of the casing device.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to design a casing device which is not damaged and can ensure that the flow rate of complex flow in the casing device is measured under the condition of continuous flow.

In order to achieve the purpose, the measurement scheme adopted by the invention is as follows:

the ultrasonic experimental device of the sleeve device utilizes different characteristics of high-frequency and low-frequency sound waves, namely, high-frequency sound wave signals are strong and easy to reflect, and low-frequency sound waves are strong in penetrability;

the ultrasonic experimental device of the sleeve device comprises a high-frequency transducer 2, a low-frequency transducer 2', a receiver 3 at the same side, a receiver 1 at the opposite side, an amplifier 4 and a signal processing system 5; wherein the high-frequency transducer 2 and the low-frequency transducer 2 'are arranged at the same position of the sleeve device, the high-frequency transducer 2 and the low-frequency transducer 2' and the receiver 3 at the same side are arranged on the same bus of the sleeve device, the opposite side of the receiver 1, which is the connecting line of the low-frequency transducer 2 'and the sleeve device, is provided with the low-frequency transducer 2', and the included angle of the connecting line of the receiver 1 at the opposite side and the sleeve is 180 degrees, the receiver 3 at the same side and the receiver 1 at the opposite side are simultaneously arranged at the upstream position or the downstream position of the high-frequency transducer 2 and the low-frequency transducer 2 ', the included angle of the high-frequency transducer 2 and the low-frequency transducer 2' and the axis of the receiver 1 at the opposite; the high-frequency transducer 2 transmits a high-frequency signal, and the high-frequency signal reaches the outer wall of the inner tube of the sleeve device, is reflected and is finally received by the receiver 3 at the same side; the low-frequency transducer 2' transmits a low-frequency signal, and the low-frequency signal is finally received by the opposite side receiver 1 through the outer layer circulation of the sleeve device, the wall of the inner pipe, the fluid in the inner pipe, the wall of the inner pipe and the outer layer circulation; the high-frequency transducer 2, the low-frequency transducer 2', the receiver 3 on the same side and the receiver 1 on the opposite side are all connected with the input end of an amplifier 4, and the output end of the amplifier 4 is connected with a signal processing system 5.

The high-frequency signal emitted by the high-frequency transducer 2 is a frequency band with good reflectivity, and the frequency of the high-frequency signal is not lower than 100 kHz.

The low-frequency signal emitted by the low-frequency transducer 2' is selected from a frequency band with good penetrability, and the signal frequency is not lower than 20 kHz.

The same-side receiver 3 can be used as a high-frequency transducer to transmit high-frequency signals at the same time, the high-frequency signals reach the outer wall of the inner tube of the sleeve device and are reflected, and finally the signals are received by the high-frequency transducer 2, so that the accuracy of the ultrasonic experimental device of the sleeve device is improved, and the time difference of the forward flow and the backward flow of the acoustic fluid is calculated respectively to calculate the flow velocity of the fluid.

The opposite side receiver 1 is used as a low-frequency transducer to transmit low-frequency signals at the same time, and the low-frequency signals are finally received by the low-frequency transducer 2' through outer circulation of the sleeve device, the wall of the inner tube, fluid in the inner tube, the wall of the inner tube and the outer circulation, so that the accuracy of the ultrasonic experimental device of the sleeve device is improved, and the flow velocity of the fluid is calculated by respectively calculating the time difference of forward flow and reverse flow of the sound wave fluid.

According to the experimental method of the ultrasonic experimental device for the casing device, the characteristics of strong and easy reflection of high-frequency sound wave signals and strong penetrability of low-frequency sound waves are utilized, and the complex flow of the casing device is analyzed by adopting synchronous signals; high-frequency signals and low-frequency signals are sent out simultaneously, the high-frequency signals are reflected on the outer wall of the inner pipe, the reflected signals are received by the receiver 3 on the same side, and the low-frequency signals penetrate through the inner pipe wall and are finally received by the receiver 1 on the opposite side through outer layer circulation, the pipe wall of the inner pipe, fluid in the inner pipe, the pipe wall of the inner pipe and the outer layer circulation; firstly, the circulation flow, namely the flow speed of the fluid between the inner pipe and the outer pipe is calculated according to the time difference between the sending and receiving of the high-frequency signal, and secondly, the flow in the inner pipe is calculated by combining the circulation flow speed fed back by the high-frequency signal and the time difference between the sending and receiving of the low-frequency signal.

In the experimental method, before the test starts, the experimental device is calibrated, the precision of the receiver is detected, and the stability of the signal processing system is detected; the experimental method specifically comprises the following steps:

s1, adjusting the power of the high-frequency transducer 2 and the low-frequency transducer 2', observing the received signals of the receiver 3 on the same side and the receiver 1 on the opposite side, and ensuring that the receiver can receive clear signals due to large signal-to-noise ratio under the selected working power;

s2, calibrating the flow measured by the high-frequency transducer 2 and the receiver 3 on the same side, giving a known rated flow, and calculating the measured flow through the time difference between the high-frequency signal sent by the high-frequency transducer 2 and the high-frequency signal received by the receiver 3 on the same side; setting a correction coefficient according to the ratio of rated flow to measured flow, and completing the flow calibration on the casing device;

s3, calibrating the flow measured by the low-frequency transducer 2 '-opposite side receiver 1, giving a known rated flow, and calculating the measured flow through the time difference between the low-frequency signal sent by the low-frequency transducer 2' and the low-frequency signal received by the opposite side receiver 1; setting a correction coefficient according to the ratio of rated flow to measured flow, wherein the high-frequency signal gives the influence of circulation flow on the sound wave signal, so that the flow calibration of the low-frequency signal is completed on a single circular tube;

s4, calculating the flow of two different states in the sleeve device: the amplifier 4 respectively amplifies the received signals of the high-frequency transducer 2, the low-frequency transducer 2', the receiver 3 on the same side and the receiver 1 on the opposite side and transmits the amplified signals to the signal processing system 5, and after the signal processing system 5 receives the signals transmitted by the amplifier 4, the flow velocity of the circulating fluid is firstly solved through the transmission time difference of the high-frequency signals, and the flow of the circulating fluid is calculated; calculating equivalent flow velocity through low-frequency signal transmission time difference, wherein the transmission time difference of the low-frequency signal comprises three parts: the first part is the propagation of low-frequency signals in the circulating fluid, the second part is the propagation of low-frequency signals in the pipe wall of the inner pipe, and the third part is the propagation of low-frequency signals in the fluid in the inner pipe; the propagation time difference of sound in the circulating fluid is calculated through a high-frequency signal, the time of sound propagation in metal on a pipe wall is constant, so that the flow in the inner pipe can be solved, and the flow of two flow states in the casing device can be obtained through integrating the time, wherein the specific calculation method comprises the following steps:

D₁，D₂outer and inner diameters of the outer tube, d₁，d₂The outer diameter and the inner diameter of the inner circular tube, alpha is the included angle between the axis of the high-frequency transducer and the low-frequency transducer and the axis of the receiver and the sleeve device on the same side, and L is the included angle between the axis of the receiver and the axis of the sleeve device on the same side₁Distance between the high-frequency transducer and the low-frequency transducer and the receiver on the same side, L₂Is the distance, S, between the high and low frequency transducers and the contralateral receiver₁To reflect the signal, S₂Penetration signal, c is sound velocity, u is flow velocity of the fluid; wherein high frequency sound wave is reflected at the outer wall of the inner tube to reflect a signal S₁Received by the receiver on the same side, the time difference between the transmitted and received signals is expressed as:

in fact, the transducer is also a receiver, and the method of final averaging of the bidirectional signals is usually adopted to reduce errors; obtaining the total transmission time T of the low-frequency signal by measurement_t(ii) a The total transmission time includes three parts: the first part is the time T taken for the low frequency signal to travel in the circulating fluid₁', the second part is the time T' taken for the low frequency signal to travel on the metal pipe wall, and the third part is the time T taken for the low frequency signal to travel in the fluid in the inner pipe₂Namely:

T_t＝T₁'+T₂+T' (2)

because the thickness of the pipe wall is much smaller compared to the diameter of the whole channel, and in addition, the propagation speed of sound in the solid is much greater than that in the fluid, the time T' for sound to travel on the metal pipe is very small and is ignored in the calculation; and T₁' approximately equal to T₁(ii) a Reflected signal S₁Transmission path and transmission signal S₂The distance traveled and the resulting effect in the sheath fluid are the same, assuming that the velocity of the fluid does not change during the minute time period of the signal being transmitted, then:

T₁＝T₁' (3)

based on the above conclusions, equation (2) reduces to:

T₂＝T_t-T₁ (4)

wherein T is_tAnd T₁The time difference between the low-frequency signal received by the opposite side receiver 1 and the low-frequency signal sent by the low-frequency transducer 2' and the time difference between the high-frequency signal received by the same side receiver 3 and the high-frequency signal sent by the high-frequency transducer 2 are known quantities, so that T is obtained₂A value of (d); t is₂Expressed as:

the flow velocity u in the inner tube is simplified by substituting equation (4) into equation (5)_hThe expression of (a) is:

from the expression, u can be seen_hCalculating according to the measured value; it is noted that the sound velocity c used in the formula is the same, and in practical application, the sound velocity of sound under the material should be replaced, and in some special application occasions, the influence of the nonlinear change of the physical property on sound propagation should be considered.

Compared with the prior art, the invention has the advantages that:

1. the invention can solve the flow measurement problem of complex flow of the casing device.

2. The invention can measure the fluid flow in the pipeline under the condition of not damaging the continuous flow field of the sleeve device.

3. The invention can be used for measuring the flow of high-temperature fluid after being modified.

Drawings

FIG. 1 is a diagram of an ultrasonic testing apparatus of the casing device of the present invention.

Fig. 2 is a schematic view of the measurement principle of the ultrasonic experimental device of the casing device.

Fig. 3 is a schematic diagram of the operation of the cannula device.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

as shown in fig. 1, the ultrasonic experimental device of the casing device of the present invention utilizes different characteristics of high and low frequency sound waves, i.e. high frequency sound wave signals are strong and easy to reflect, and low frequency sound waves are strong in penetrability; the ultrasonic experimental device of the sleeve device comprises a high-frequency transducer 2, a low-frequency transducer 2', a receiver 3 at the same side, a receiver 1 at the opposite side, an amplifier 4 and a signal processing system 5; wherein the high-frequency transducer 2 and the low-frequency transducer 2 'are arranged at the same position of the sleeve device, the high-frequency transducer 2 and the low-frequency transducer 2' and the receiver 3 at the same side are arranged on the same bus of the sleeve device, the opposite side of the receiver 1, which is the connecting line of the low-frequency transducer 2 'and the sleeve device, is provided with the low-frequency transducer 2', and the included angle of the connecting line of the receiver 1 at the opposite side and the sleeve is 180 degrees, the receiver 3 at the same side and the receiver 1 at the opposite side are simultaneously arranged at the upstream position or the downstream position of the high-frequency transducer 2 and the low-frequency transducer 2 ', the included angle of the high-frequency transducer 2 and the low-frequency transducer 2' and the axis of the receiver 1 at the opposite; the high-frequency transducer 2 transmits a high-frequency signal, and the high-frequency signal reaches the outer wall of the inner tube of the sleeve device, is reflected and is finally received by the receiver 3 at the same side; the low-frequency transducer 2' transmits a low-frequency signal, and the low-frequency signal is finally received by the opposite side receiver 1 through the outer layer circulation of the sleeve device, the wall of the inner pipe, the fluid in the inner pipe, the wall of the inner pipe and the outer layer circulation; the high-frequency transducer 2, the low-frequency transducer 2', the receiver 3 on the same side and the receiver 1 on the opposite side are all connected with the input end of an amplifier 4, and the output end of the amplifier 4 is connected with a signal processing system 5.

As a preferred embodiment of the present invention, the high frequency transducer 2 emits a high frequency signal having a frequency band with good reflectivity and a frequency of not lower than 100 kHz.

As a preferred embodiment of the invention, the low-frequency signal emitted by the low-frequency transducer 2' is a frequency band with good penetration, and the signal frequency is not lower than 20 kHz.

In a preferred embodiment of the present invention, the same-side receiver 3 can simultaneously serve as a high-frequency transducer to transmit a high-frequency signal, and the high-frequency signal reaches the outer wall of the inner tube of the casing device and is reflected to be finally received by the high-frequency transducer 2, so as to improve the accuracy of the ultrasonic experimental apparatus of the casing device, and respectively calculate the time difference between the forward flow and the backward flow of the acoustic fluid to calculate the fluid flow rate.

As a preferred embodiment of the present invention, the opposite-side receiver 1 simultaneously serves as a low-frequency transducer to transmit a low-frequency signal, and the low-frequency signal is finally received by the low-frequency transducer 2' through the outer-layer circular flow, the inner-tube wall, the fluid in the inner tube, the inner-tube wall, and the outer-layer circular flow of the casing device, so as to improve the precision of the casing device ultrasonic experimental apparatus and respectively calculate the time difference between the forward flow and the reverse flow of the acoustic fluid to calculate the fluid flow rate.

According to the experimental method of the ultrasonic experimental device for the casing device, disclosed by the invention, the complex flow of the casing device is analyzed by utilizing the characteristics of strong and easy reflection of a high-frequency sound wave signal and strong penetrability of a low-frequency sound wave and adopting a synchronous signal; high-frequency signals and low-frequency signals are sent out simultaneously, the high-frequency signals are reflected on the outer wall of the inner pipe, the reflected signals are received by the receiver 3 on the same side, and the low-frequency signals penetrate through the inner pipe wall and are finally received by the receiver 1 on the opposite side through outer layer circulation, the pipe wall of the inner pipe, fluid in the inner pipe, the pipe wall of the inner pipe and the outer layer circulation; firstly, the circulation flow, namely the flow speed of the fluid between the inner pipe and the outer pipe is calculated according to the time difference between the sending and receiving of the high-frequency signal, and secondly, the flow in the inner pipe is calculated by combining the circulation flow speed fed back by the high-frequency signal and the time difference between the sending and receiving of the low-frequency signal.

According to the experimental method, before the test is started, calibration, receiver precision detection and signal processing system stability detection are carried out on an experimental device; the experimental method specifically comprises the following steps:

s1, adjusting the power of the high-frequency transducer 2 and the low-frequency transducer 2', observing the received signals of the receiver 3 on the same side and the receiver 1 on the opposite side, and ensuring that the receiver can receive clear signals due to large signal-to-noise ratio under the selected working power;

s2, calibrating the flow measured by the high-frequency transducer 2 and the receiver 3 on the same side, giving a known rated flow, and calculating the measured flow through the time difference between the high-frequency signal sent by the high-frequency transducer 2 and the high-frequency signal received by the receiver 3 on the same side; setting a correction coefficient according to the ratio of rated flow to measured flow, and completing the flow calibration on the casing device;

s3, calibrating the flow measured by the low-frequency transducer 2 '-opposite side receiver 1, giving a known rated flow, and calculating the measured flow through the time difference between the low-frequency signal sent by the low-frequency transducer 2' and the low-frequency signal received by the opposite side receiver 1; setting a correction coefficient according to the ratio of rated flow to measured flow, wherein the high-frequency signal gives the influence of circulation flow on the sound wave signal, so that the flow calibration of the low-frequency signal is completed on a single circular tube;

s4, calculating the flow of two different states in the sleeve device: the amplifier 4 respectively amplifies the received signals of the high-frequency transducer 2, the low-frequency transducer 2', the receiver 3 on the same side and the receiver 1 on the opposite side and transmits the amplified signals to the signal processing system 5, and after the signal processing system 5 receives the signals transmitted by the amplifier 4, the flow velocity of the circulating fluid is firstly solved through the transmission time difference of the high-frequency signals, and the flow of the circulating fluid is calculated; calculating equivalent flow velocity through low-frequency signal transmission time difference, wherein the transmission time difference of the low-frequency signal comprises three parts: the first part is the propagation of low-frequency signals in the circulating fluid, the second part is the propagation of low-frequency signals in the pipe wall of the inner pipe, and the third part is the propagation of low-frequency signals in the fluid in the inner pipe; the propagation time difference of sound in the circulating fluid is calculated through a high-frequency signal, the time of sound propagation in metal on a pipe wall is constant, so that the flow in the inner pipe can be solved, and the flow of two flow states in the casing device can be obtained through integrating the time, wherein the specific calculation method comprises the following steps:

as shown in FIG. 2, D₁，D₂Outer and inner diameters of the outer tube, d₁，d₂The outer diameter and the inner diameter of the inner circular tube, alpha is the included angle between the axis of the high-frequency transducer and the low-frequency transducer and the axis of the receiver and the sleeve device on the same side, and L is the included angle between the axis of the receiver and the axis of the sleeve device on the same side₁Distance between the high-frequency transducer and the low-frequency transducer and the receiver on the same side, L₂Is the distance, S, between the high and low frequency transducers and the contralateral receiver₁To reflect the signal, S₂Penetration signal, c is sound velocity, u is flow velocity of the fluid; wherein high frequency sound wave is reflected at the outer wall of the inner tube to reflect a signal S₁Received by the receiver on the same side, the time difference between the transmitted and received signals is expressed as:

in fact, the transducer is also a receiver, and the method of final averaging of the bidirectional signals is usually adopted to reduce errors; obtaining the total transmission time T of the low-frequency signal by measurement_t(ii) a The total transmission time includes three parts: the first part is the time T taken for the low frequency signal to travel in the circulating fluid₁' the second part is low-frequency signal on the wall of the metal pipeThe time T' for the upper transmission, and the third part is the time T for the low-frequency signal to be transmitted in the fluid in the inner tube₂Namely:

T_t＝T₁'+T₂+T' (2)

because the thickness of the pipe wall is much smaller compared to the diameter of the whole channel, and in addition, the propagation speed of sound in the solid is much greater than that in the fluid, the time T' for sound to travel on the metal pipe is very small and is ignored in the calculation; and T₁' approximately equal to T₁(ii) a Reflected signal S₁Transmission path and transmission signal S₂The distance traveled and the resulting effect in the sheath fluid are the same, assuming that the velocity of the fluid does not change during the minute time period of the signal being transmitted, then:

T₁＝T₁' (3)

based on the above conclusions, equation (2) reduces to:

T₂＝T_t-T₁ (4)

wherein T is_tAnd T₁The time difference between the low-frequency signal received by the opposite side receiver 1 and the low-frequency signal sent by the low-frequency transducer 2' and the time difference between the high-frequency signal received by the same side receiver 3 and the high-frequency signal sent by the high-frequency transducer 2 are known quantities, so that T is obtained₂A value of (d); t is₂Expressed as:

the flow velocity u in the inner tube is simplified by substituting equation (4) into equation (5)_hThe expression of (a) is:

from the expression, u can be seen_hCalculating according to the measured value; it is noted that the sound velocity c used in the formula is the same, and in practical application the sound velocity of sound under the material should be replaced, and in some special casesThe application of (1) is to consider the influence of the nonlinear change of the physical properties on sound propagation.