High-temperature sound calibration device and method

Abstract

The invention discloses a high-temperature acoustic calibration device and method. The device comprises a heating container, a high-temperature and high-pressure liquid pump, a regulating valve, an ultrasonic sensor mounting base, a test pipe section, a standard flowmeter, a pressure control structure, a safety valve, an exhaust valve, geometric measurement equipment and a main control computer. The heating container, the high-temperature and high-pressure liquid pump, the test pipe section and the standard flow meter are sequentially connected through pipelines, the standard flow meter is connected to the heating container through a pipeline, and an outlet of the heating container is connected with an inlet of the high-temperature and high-pressure liquid pump; the two ends of the test pipe section are respectively provided with an ultrasonic sensor mounting base, and the ultrasonic sensor mounting bases, the geometric measurement equipment and the test pipe section are coaxial. According to the invention, parameters such as temperature, pressure, flow, geometric expansion and the like can be accurately controlled and measured under high-temperature and high-pressure medium conditions, so that sound velocity calibration and test functions of equipment such as an ultrasonic flowmeter and a sound velocity meter are realized.

Description

Technical Field

[0001] The invention relates to the technical field of sound velocity parameter measurement of an ultrasonic flowmeter, and in particular to a high-temperature acoustic calibration device and method. Background Art

[0002] The speed of sound is a key parameter in the intersection of multiple disciplines such as fluid dynamics, acoustics, and thermodynamics. The measurement of the speed of sound plays a vital role in the analysis of fluid characteristics and ultrasonic flow measurement. Traditional methods of measuring the speed of sound are mainly carried out under normal temperature and pressure medium conditions, but there is still a lack of effective testing methods for the speed of sound parameters under high temperature and high pressure conditions. On the one hand, traditional speed of sound calibration devices are difficult to accurately simulate the high pressure and flow conditions on site, and the calibration results are not representative enough; on the other hand, the speed of sound measurement model under high temperature and high pressure medium conditions is not perfect, and a corresponding test device that can simulate the site and is traceable is needed. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention aims to provide a high-temperature acoustic calibration device and method.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A high temperature acoustic calibration device, comprising a heating container, a high temperature and high pressure liquid pump, a regulating valve, an ultrasonic sensor mounting base, a test pipe section, a standard flow meter, a pressure control structure, a safety valve, an exhaust valve, a geometric measurement device and a main control computer;

[0006] The heating container, the high-temperature and high-pressure liquid pump, the test pipe section and the standard flow meter are connected in sequence through pipelines, the standard flow meter is connected to the heating container through a pipeline, and the outlet of the heating container is connected to the inlet of the high-temperature and high-pressure liquid pump;

[0007] Both ends of the test pipe section are respectively installed with mounting bases for mounting ultrasonic sensors, the ultrasonic sensor mounting bases are coaxial with the test pipe section, and the ultrasonic sensor to be calibrated is installed at one end of the ultrasonic sensor mounting base facing the inside of the test pipe section; the geometric measurement device is used to measure the change in the axial length of the test pipe;

[0008] One or more sections of the pipeline are provided with a regulating valve, which is used to control the flow rate of the liquid; the heating container is also connected to a pressure control structure, a safety valve and an exhaust valve; the pressure control structure is used to compensate for the volume change of the heating container caused by the thermal expansion and contraction of the liquid;

[0009] The high-temperature and high-pressure liquid pump, regulating valve, standard flow meter, pressure control structure, safety valve, exhaust valve, geometric measuring equipment and ultrasonic sensor to be calibrated are all connected to the main control computer for communication.

[0010] Furthermore, geometric measuring devices are provided on the outer sides of the ultrasonic sensor mounting bases at both ends of the test pipe section, and each geometric measuring device is coaxial with the test pipe section. The geometric measuring devices on both sides are used to measure the distance between the relative ultrasonic sensor mounting bases and transmit it to the main control computer. The main control computer calculates the change in the axial length of the test pipe section according to the change in the distance between the relative ultrasonic sensor mounting bases measured by the geometric measuring device.

[0011] Furthermore, the inner diameter of the test pipe section is greater than twice the diameter of the ultrasonic sensor to be calibrated or a sound-absorbing material is attached to the inner wall of the test pipe section.

[0012] Furthermore, the heating container includes a heating device and a temperature control module. The heating device is used to heat the liquid. The temperature control module is used to detect the temperature of the liquid in the heating container and control the start and stop of the heating device to accurately control the liquid temperature and ensure that the temperature change of the liquid during the test meets the test requirements.

[0013] Furthermore, the outside of the heating container, the high-temperature and high-pressure liquid pump, the test pipe section, the standard flow meter and each section of the pipeline are tightly wrapped with insulation materials.

[0014] Furthermore, two cross-arranged intermediate pipes 1 and 2 are added between the pipe connecting the high-temperature and high-pressure liquid pump and the test pipe section and the pipe connecting the standard flow meter and the heating container; a regulating valve 1 is provided on the pipe connecting the high-temperature and high-pressure liquid pump and the test pipe section, a regulating valve 2 is provided on the pipe connecting the standard flow meter and the heating container, and a regulating valve 3 and a regulating valve 4 are provided on the intermediate pipe 1 and the intermediate pipe 2 respectively; one end of the intermediate pipe 1 is connected between the high-temperature and high-pressure liquid pump and the regulating valve 1, and the other end is connected between the standard flow meter and the regulating valve 2; one end of the intermediate pipe 2 is connected between the regulating valve 1 and the test pipe section, and the other end is connected between the heating container and the regulating valve 2.

[0015] The present invention also provides a working method of the high temperature acoustic calibration device, the specific process is:

[0016] Before work, use the geometric measuring equipment on both sides to measure the distance between the ultrasonic sensor mounting base and the corresponding one, which are recorded as L 11 and L 21 ;

[0017] When working, the interior of the heating container is filled with liquid at normal temperature and pressure, the temperature of the liquid is increased by the heating container, and the high-temperature and high-pressure liquid pump starts working, so that the liquid moves slowly, and the pressure control structure is kept at normal pressure;

[0018] When the liquid temperature reaches 40℃, keep the temperature constant and open the exhaust valve to gradually exhaust the air contained in the liquid to minimize the gas content in the liquid.

[0019] When the liquid no longer contains gas, the exhaust valve is closed, and the internal pressure of the liquid is maintained at the set pressure condition through the pressure control structure. The heating container continues to increase the temperature of the liquid so that it gradually reaches the set temperature condition. When the temperature and pressure reach the preset state, the pressure control structure is opened to keep the pressure stable, and the flow rate is increased. The main control computer is used to record the average temperature and pressure of the liquid during this period, the flow rate measured by the standard flow meter, the ultrasonic frequency of the ultrasonic sensor, and the measured sound velocity and flow rate within the set time period;

[0020] Continue to increase the flow rate, and use the main control computer to record the average temperature and pressure of the liquid during the set period, the flow rate measured by the standard flow meter, the ultrasonic frequency of the ultrasonic sensor and the measured sound velocity and flow rate, as well as the distance L between the geometric measurement equipment on both sides and the relative ultrasonic sensor mounting base. 12 and L 22 ;

[0021] The main control computer uses the temperature and pressure measurement results to calculate the standard sound speed according to the IAPWS IF97 standard formula, and completes the sound speed calibration by comparing it with the sound speed measured by the ultrasonic sensor;

[0022] The main control computer calibrates the flow rate by comparing the flow rate and flow velocity measured by the standard flow meter with the flow velocity measured by the ultrasonic sensor;

[0023] The main control computer calculates and measures the change in the axial length of the test pipe section, which is equal to L 12 +L 22 -L 11 -L 21 , determine whether the geometric parameter expansion model is accurate during the sound speed calculation process;

[0024] The main control computer obtains the frequency response characteristics of the ultrasonic sensor affected by temperature by recording the temperature and ultrasonic frequency;

[0025] After the test is completed, the flow rate will be gradually reduced to 0m 3 / h, gradually reduce the liquid pressure to normal pressure through the pressure control structure, and let it stand until the liquid cools down. The current test is completed.

[0026] The beneficial effect of the present invention is that the present invention can be used to accurately control and measure parameters such as temperature, pressure, flow, geometric expansion, etc. under high temperature and high pressure medium conditions, thereby realizing the calibration function of the ultrasonic sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of a one-way test structure of a high-temperature acoustic calibration device in Example 1 of the present invention;

[0028] Figure 2 Schematic diagram of the bidirectional test structure of the high-temperature acoustic calibration device in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment.

[0030] Example 1

[0031] This embodiment provides a high temperature acoustic calibration device, such as Figure 1 As shown, it includes a heating container 1, a high-temperature and high-pressure liquid pump 2, a regulating valve 3, an ultrasonic sensor mounting base 4, a test pipe section 5, a standard flow meter 6, a pressure control structure 7, a safety valve 8, an exhaust valve 9, a geometric measuring device 10 and a main control computer 11.

[0032] The heating container 1, the high-temperature and high-pressure liquid pump 2, the test pipe section 5 and the standard flow meter 6 are connected in sequence through pipelines. The standard flow meter 6 is connected to the heating container 1 through a pipeline. The outlet of the heating container 1 is connected to the inlet of the high-temperature and high-pressure liquid pump 2.

[0033] The two ends of the test pipe section 5 are respectively installed with ultrasonic sensor mounting bases 4, the ultrasonic sensor mounting bases 4 are coaxial with the test pipe section 5, and the ultrasonic sensor to be calibrated is installed at one end of the ultrasonic sensor mounting base 4 facing the inside of the test pipe section 5; the geometric measurement device 10 is used to measure the change in the axial length of the test pipe 5. Specifically, the end of the ultrasonic sensor mounting base 4 facing the inside of the test pipe section 5 can be inserted into the test pipe section 5, and the depth of the insertion is determined according to the length of the sound channel to be measured.

[0034] The high-temperature and high-pressure liquid pump 2, the regulating valve 3, the standard flow meter 6, the pressure control structure 7, the safety valve 8, the exhaust valve 9, the geometric measuring device 10 and the ultrasonic sensor to be calibrated are all communicatively connected to the main control computer 11. The high-temperature and high-pressure liquid pump 2, the regulating valve 3, the standard flow meter 6, the pressure control structure 7, the safety valve 8 and the exhaust valve 9 are used to control the state of the liquid medium in the device. The standard flow meter 6 and the geometric measuring device 10 are used to transmit data to the main control computer 11.

[0035] In the above-mentioned high-temperature acoustic calibration device, the pipeline is used to carry the liquid medium and connect the heating container, the test pipe section, the high-temperature and high-pressure liquid pump and the standard flow meter. Through the design of the pipeline, the liquid medium runs in the test pipe section in a clockwise direction.

[0036] In this embodiment, a regulating valve 3 is provided on one or more sections of the pipeline, and the regulating valve 3 is used to control the flow rate of the liquid to reach a predetermined test flow rate.

[0037] In the above-mentioned high-temperature acoustic calibration device, the high-temperature and high-pressure liquid pump 2 is used to provide driving force for the flow of liquid to enable it to move. The state of the liquid must meet the calibration temperature, pressure and flow design requirements.

[0038] In the above-mentioned high-temperature acoustic calibration device, the standard flow meter is used to measure the flow rate of the liquid and calibrate the measurement result of the ultrasonic sensor.

[0039] In this embodiment, geometric measuring devices 10 are provided on the outer sides of the ultrasonic sensor mounting bases 4 at both ends of the test pipe segment 5, and each geometric measuring device 10 is coaxial with the test pipe segment 5. The geometric measuring devices 10 on both sides are used to measure the distance between the relative ultrasonic sensor mounting bases 4 and transmit it to the main control computer 11. The main control computer 11 calculates the change in the axial length of the test pipe segment 5 according to the change in the distance between the relative ultrasonic sensor mounting bases 4 measured by the geometric measuring devices 10.

[0040] Assuming that the distances between the two geometric measuring devices 10 and the relative ultrasonic sensor mounting bases 4 under cold conditions before the experiment are L 11 , L 21 After the liquid reaches the temperature, pressure and flow conditions required for calibration, the distance between the two geometric measuring devices 10 and the relative ultrasonic sensor mounting base 4 is L 12 , L 22 , then the change in the axial length of the test pipe section 5 is equal to L 12 +L 22 -L 11 -L 21 .

[0041] In this embodiment, the heating container 1 is also connected to a pressure control structure 7, a safety valve 8 and an exhaust valve 9. The pressure control structure 7 is used to prevent the medium pressure caused by the deformation of the liquid volume during the heating process from exceeding the maximum allowable pressure. The exhaust valve 9 is used to exhaust the gas contained in the liquid in the initial state. The safety valve 8 is used to discharge part of the steam or liquid in time when the liquid pressure inside the heating container exceeds the maximum allowable pressure, so as to ensure that the heating container 1 always operates in a safe state.

[0042] In this embodiment, the test pipe section 5 may be a smooth pipe, and the inner diameter of the test pipe section may be set to be greater than twice the diameter of the ultrasonic sensor to be calibrated or a sound absorbing material may be attached to the inner wall of the test pipe section.

[0043] In this embodiment, the heating container 1 includes a heating device and a temperature control module. The heating device is used to heat the liquid. The temperature control module is used to detect the temperature of the liquid in the heating container and control the start and stop of the heating device to accurately control the temperature of the liquid and ensure that the temperature change of the liquid during the test meets the test requirements. According to the requirements, a rectifier structure or an internal circulation structure can be added to the heating container to increase the efficiency of heat exchange.

[0044] In this embodiment, the heating container 1, the high-temperature and high-pressure liquid pump 2, the test pipe section 5, the standard flow meter 6 and the exterior of each section of the pipeline are tightly wrapped with insulation materials.

[0045] Example 2

[0046] This embodiment provides another structure of a high temperature acoustic calibration device. Figure 2 As shown, the structure of the high-temperature acoustic calibration device of this embodiment is basically the same as that of embodiment 1, and the main difference is that two sections of cross-arranged intermediate pipes 12 and 13 are added between the pipe connecting the high-temperature and high-pressure liquid pump 2 and the test pipe section 5 and the pipe connecting the standard flow meter 6 and the heating container 1; a regulating valve 1 31 is provided on the pipe connecting the high-temperature and high-pressure liquid pump 2 and the test pipe section 5, a regulating valve 2 32 is provided on the pipe connecting the standard flow meter 6 and the heating container 1, and a regulating valve 3 33 and a regulating valve 4 34 are provided on the intermediate pipe 12 and the intermediate pipe 2 13 respectively; one end of the intermediate pipe 12 is connected between the high-temperature and high-pressure liquid pump 2 and the regulating valve 1 31, and the other end is connected between the standard flow meter 6 and the regulating valve 2 32; one end of the intermediate pipe 2 13 is connected between the regulating valve 1 31 and the test pipe section 5, and the other end is connected between the heating container 1 and the regulating valve 2 32.

[0047] Through the above-mentioned pipeline and regulating valve settings, the flow direction of the liquid can be controlled, thereby achieving two-way flow of the liquid.

[0048] When regulating valve three 33 and regulating valve four 34 are closed and regulating valve one 31 and regulating valve two 32 are opened, the liquid moves clockwise in the test pipe section 5; when regulating valve three 33 and regulating valve four 34 are opened and regulating valve one 31 and regulating valve two 32 are closed, the liquid moves counterclockwise in the test pipe section 5.

[0049] Example 3

[0050] This embodiment provides an application example of the high temperature acoustic calibration device described in Embodiment 1.

[0051] In this embodiment, the heating container is provided with an external heating wire and an internal platinum resistance type high-precision temperature control module and a rectifier plate; the regulating valve adopts a high-temperature and high-pressure electromagnetic valve; the pipe body of the test pipe section adopts 316 stainless steel material, and the inner wall of the pipe body is attached with 10mm sound-absorbing material; the standard flowmeter adopts a high-temperature and high-pressure Coriolis mass flowmeter; the pressure control structure adopts a high-temperature and high-pressure stainless steel expansion joint; the geometric measurement equipment adopts 2 laser interferometers and a reflector group; the pipeline adopts a single-circulation pipeline, made of 316 stainless steel material, with a design temperature of 250°C and a design pressure of 10Mpa. The outside of the heating container 1, the high-temperature and high-pressure liquid pump 2, the test pipe section 5, the standard flowmeter 6 and each section of the pipeline are tightly wrapped with a 50mm thick insulation material.

[0052] Before work, use the geometric measuring devices 10 on both sides to measure the distances between the ultrasonic sensor mounting bases 4 and the corresponding ones, which are respectively recorded as L 11 and L 21 .

[0053] During operation, the interior of the heating container is filled with liquid at normal temperature and pressure (water in this embodiment). The temperature of the liquid is increased by the heating container, and the high-temperature and high-pressure liquid pump starts working to make the liquid move slowly, while the pressure control structure remains at normal pressure.

[0054] When the liquid temperature reaches 40°C, keep the temperature constant and open the exhaust valve to gradually exhaust the air contained in the liquid to minimize the gas content in the liquid.

[0055] When the liquid no longer contains gas, close the exhaust valve and maintain the internal pressure of the liquid at 8MPa through the pressure control structure. The heating container continues to increase the temperature of the liquid to gradually reach 250℃. When the temperature and pressure reach the preset state, increase the flow rate to 50m 3 / h, starting temperature 250℃, pressure 8MPa, flow rate 50m 3 / h. Within a period of time (not less than 5 minutes), the main control computer 11 is used to record the average temperature and pressure of the liquid, the flow rate measured by the standard flow meter, the ultrasonic frequency of the ultrasonic sensor, and the measured sound velocity and flow rate.

[0056] Increase flow rate to 100m 3 / h. Within a period of time (not less than 5 minutes), the main control computer 11 records the average temperature and pressure of the liquid during this period, the flow rate measured by the standard flow meter, the ultrasonic frequency of the ultrasonic sensor and the measured sound velocity and flow rate, and the distance L between the geometric measuring devices on both sides and the relative ultrasonic sensor mounting base 4. 12 , L 22 .

[0057] The main control computer 11 uses the measurement results of temperature and pressure to calculate the standard sound speed according to the IAPWS IF97 standard formula, and completes the calibration of the sound speed by comparing it with the sound speed measured by the ultrasonic sensor.

[0058] The main control computer 11 completes the flow rate calibration by comparing the flow rate and flow velocity measured by the standard flow meter with the flow velocity measured by the ultrasonic sensor.

[0059] The main control computer 11 calculates and measures the change in the axial length of the test pipe section 5 to be equal to L 12 +L 22 -L 11 -L 21 , to determine whether the geometric parameter expansion model is accurate during the sound speed calculation process.

[0060] The main control computer 11 obtains the frequency response characteristics of the ultrasonic sensor affected by temperature by recording the temperature and ultrasonic frequency.

[0061] After the test is completed, the flow rate will be gradually reduced to 0m 3 / h, gradually reduce the liquid pressure to normal pressure through the pressure control structure, and let it stand until the liquid cools down. The current test is completed.

[0062] For those skilled in the art, various corresponding changes and modifications can be made according to the above technical solutions and concepts, and all of these changes and modifications should be included in the protection scope of the claims of the present invention.

Claims

1. A high temperature acoustic calibration device, characterized in that: It includes a heating container, a high-temperature and high-pressure liquid pump, a regulating valve, an ultrasonic sensor mounting base, a test pipe section, a standard flow meter, a pressure control structure, a safety valve, an exhaust valve, a geometric measuring device and a main control computer; The heating container, the high-temperature and high-pressure liquid pump, the test pipe section and the standard flow meter are connected in sequence through pipelines, the standard flow meter is connected to the heating container through a pipeline, and the outlet of the heating container is connected to the inlet of the high-temperature and high-pressure liquid pump; Both ends of the test pipe section are respectively installed with mounting bases for mounting ultrasonic sensors, the ultrasonic sensor mounting bases are coaxial with the test pipe section, and the ultrasonic sensor to be calibrated is installed at one end of the ultrasonic sensor mounting base facing the inside of the test pipe section; the geometric measurement device is used to measure the change in the axial length of the test pipe; One or more sections of the pipeline are provided with a regulating valve, which is used to control the flow rate of the liquid; the heating container is also connected to a pressure control structure, a safety valve and an exhaust valve; the pressure control structure is used to compensate for the volume change of the heating container caused by the thermal expansion and contraction of the liquid; The high-temperature and high-pressure liquid pump, regulating valve, standard flow meter, pressure control structure, safety valve, exhaust valve, geometric measuring equipment and ultrasonic sensor to be calibrated are all connected to the main control computer for communication.

2. The high temperature acoustic calibration device according to claim 1, characterized in that: Geometric measuring devices are provided on the outer sides of the ultrasonic sensor mounting bases at both ends of the test pipe section, and each geometric measuring device is coaxial with the test pipe section. The geometric measuring devices on both sides are used to measure the distance between the relative ultrasonic sensor mounting bases and transmit it to the main control computer. The main control computer calculates the change in the axial length of the test pipe section according to the change in the distance between the relative ultrasonic sensor mounting bases measured by the geometric measuring devices.

3. The high temperature acoustic calibration device according to claim 1, characterized in that: The inner diameter of the test pipe section is greater than twice the diameter of the ultrasonic sensor to be calibrated or a sound absorbing material is attached to the inner wall of the test pipe section.

4. The high temperature acoustic calibration device according to claim 1, characterized in that: The heating container includes a heating device and a temperature control module. The heating device is used to heat the liquid. The temperature control module is used to detect the temperature of the liquid in the heating container and control the start and stop of the heating device to accurately control the liquid temperature and ensure that the temperature change of the liquid during the test meets the test requirements.

5. The high temperature acoustic calibration device according to claim 1, characterized in that: The outside of the heating container, high-temperature and high-pressure liquid pump, test pipe section, standard flow meter and each section of the pipeline are tightly wrapped with insulation material.

6. The high temperature acoustic calibration device according to claim 1, characterized in that: Two cross-arranged intermediate pipes 1 and 2 are added between the pipe connecting the high-temperature and high-pressure liquid pump and the test pipe section and the pipe connecting the standard flow meter and the heating container; a regulating valve 1 is provided on the pipe connecting the high-temperature and high-pressure liquid pump and the test pipe section, a regulating valve 2 is provided on the pipe connecting the standard flow meter and the heating container, and a regulating valve 3 and a regulating valve 4 are provided on the intermediate pipe 1 and the intermediate pipe 2 respectively; one end of the intermediate pipe 1 is connected between the high-temperature and high-pressure liquid pump and the regulating valve 1, and the other end is connected between the standard flow meter and the regulating valve 2; one end of the intermediate pipe 2 is connected between the regulating valve 1 and the test pipe section, and the other end is connected between the heating container and the regulating valve 2.

7. A method for operating the high temperature acoustic calibration device according to any one of claims 1 to 6, characterized in that: The specific process is: Before work, use the geometric measuring equipment on both sides to measure the distance between the ultrasonic sensor mounting base and the corresponding one, which are recorded as L 11 and L 21 ; When working, the interior of the heating container is filled with liquid at normal temperature and pressure, the temperature of the liquid is increased by the heating container, and the high-temperature and high-pressure liquid pump starts working, so that the liquid moves slowly, and the pressure control structure is kept at normal pressure; When the liquid temperature reaches 40℃, keep the temperature constant and open the exhaust valve to gradually exhaust the air contained in the liquid to minimize the gas content in the liquid. When the liquid no longer contains gas, the exhaust valve is closed, and the internal pressure of the liquid is maintained at the set pressure condition through the pressure control structure. The heating container continues to increase the temperature of the liquid so that it gradually reaches the set temperature condition. When the temperature and pressure reach the preset state, the pressure control structure is opened to keep the pressure stable, and the flow rate is increased. The main control computer is used to record the average temperature and pressure of the liquid during this period, the flow rate measured by the standard flow meter, the ultrasonic frequency of the ultrasonic sensor, and the measured sound velocity and flow rate within the set time period; Continue to increase the flow rate, and use the main control computer to record the average temperature and pressure of the liquid during the set period, the flow rate measured by the standard flow meter, the ultrasonic frequency of the ultrasonic sensor and the measured sound velocity and flow rate, as well as the distance L between the geometric measuring devices on both sides and the relative ultrasonic sensor mounting base. 12 and L 22 ; The main control computer uses the temperature and pressure measurement results to calculate the standard sound speed according to the IAPWS IF97 standard formula, and completes the sound speed calibration by comparing it with the sound speed measured by the ultrasonic sensor; The main control computer calibrates the flow rate by comparing the flow rate and flow velocity measured by the standard flow meter with the flow velocity measured by the ultrasonic sensor; The main control computer calculates and measures the change in the axial length of the test pipe section, which is equal to L 12 +L 22 -L 11 -L 21 , determine whether the geometric parameter expansion model is accurate during the sound speed calculation process; The main control computer obtains the frequency response characteristics of the ultrasonic sensor affected by temperature by recording the temperature and ultrasonic frequency; After the test is completed, the flow rate will be gradually reduced to 0m 3 / h, gradually reduce the liquid pressure to normal pressure through the pressure control structure, and let it stand until the liquid cools down. The current test is completed.

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