Dynamic calibration system for air free field pressure sensor

Abstract

The invention relates to a dynamic calibration system for an air free field pressure sensor, and belongs to the field of dynamic pressure measurement. The pressure measuring module is used for measuring initial pressure data of the shock wave chamber; the temperature measuring module is used for measuring initial temperature data of the shock wave chamber; the pressure console controls the pressure source to generate gas shock waves into the shock wave chamber; the air free field pressure sensor is used for transmitting shock wave pressure data to the signal conditioner; the signal conditioner is used for converting the shock wave pressure data into recognizable shock wave pressure data; the speed measurement system is used for sending shock wave speed data to the data acquisition and analysis system; the data acquisition and analysis system is used for sending the initial pressure data, the initial temperature data, the shock wave pressure data and the shock wave speed data to output equipment to calibrate dynamic indexes of the air free field pressure sensor; the dynamic calibration method for the air free field pressure sensor is realized, and dynamic calibration is provided for the air free field pressure sensor with the pressure range within 0.01-7 MPa.

Description

Technical Field

[0001] The invention belongs to the field of dynamic pressure measurement and relates to a dynamic calibration system for an air free-field pressure sensor. Background Art

[0002] Shock wave pressure can cause damage to personnel, helicopters, ships, civil tunnels, bridges, buildings and other targets. It has the characteristics of extremely short rise time. The shock wave range and destructive ability are important technical and tactical indicators for measuring the damage effect of warheads, and are important assessment indicators for various weapons and ammunition. Air free field pressure sensor is a sensor specially designed to measure the dynamic change of pressure in air free field, which is commonly used in the field of measuring shock wave pressure.

[0003] The air free field usually refers to a non-reflective and non-interference environment, which enables the sensor to accurately sense and measure changes in air pressure. Its structural shape is usually pencil-shaped. The pen shaft, which is several hundred millimeters long, is to ensure that the reflected wave at the installation point can reach the assembly point of the sensitive element only after the incident wave measurement is completed. The bullet-shaped streamlined structure of the pen tip, which is more than one hundred millimeters long, is to prevent the impact airflow from changing the flow pattern, so that the test point is more in line with the characteristics of free field measurement. Compared with other dynamic pressure sensors, the air free field pressure sensor has significant differences: 1) The structural type is very special, it is a streamlined pencil design; 2) Its calibration needs to consider the particularity of the free field pressure; 3) It has a short rise time, high resonant frequency, and obvious dynamic response characteristics, and dynamic calibration is required. Therefore, it is urgent to study the dynamic calibration method of the air free field pressure sensor. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, propose an air free-field pressure sensor dynamic calibration system, implement an air free-field pressure sensor dynamic calibration method, and provide dynamic calibration for air free-field pressure sensors within a pressure range of 0.01-7MPa.

[0005] The solution of the present invention is:

[0006] An air free-field pressure sensor dynamic calibration system includes a shock wave chamber, a pressure control console, a pressure source, an air free-field pressure sensor, a signal conditioner, a pressure measurement module, a temperature measurement module, a speed measurement system, a data acquisition and analysis system, and an output device;

[0007] The shock wave chamber is axially arranged horizontally; the air free field pressure sensor, signal conditioner, pressure measurement module, temperature measurement module and speed measurement system are all arranged on the shock wave chamber;

[0008] Pressure measurement module: measures the initial pressure of the shock wave chamber and transmits the initial pressure data to the data acquisition and analysis system;

[0009] Temperature measurement module: measures the initial temperature of the shock wave chamber and transmits the initial temperature data to the data acquisition and analysis system;

[0010] Pressure control console: controls the pressure source to input high-pressure gas into the shock wave chamber to generate gas shock waves;

[0011] Air free field pressure sensor: measures the gas shock wave pressure in the shock wave chamber and transmits the shock wave pressure data to the signal conditioner;

[0012] Signal conditioner: receiving shock wave pressure data from the air free field pressure sensor; adjusting the voltage of the shock wave pressure data to generate recognizable shock wave pressure data, and sending the recognizable shock wave pressure data to the data acquisition and analysis system;

[0013] Velocity measurement system: measures the velocity of gas shock waves and sends the shock wave velocity data to the data acquisition and analysis system;

[0014] Data acquisition and analysis system: receiving initial pressure data from the pressure measurement module; receiving initial temperature data from the temperature measurement module; receiving recognizable shock wave pressure data from the signal conditioner; receiving shock wave velocity data from the velocity measurement system; sending initial pressure data, initial temperature data, shock wave pressure data, and shock wave velocity data to the output device;

[0015] Output device: Receives initial pressure data, initial temperature data, shock wave pressure data, and shock wave velocity data from the data acquisition and analysis system, and calibrates the dynamic indicators of the air free field pressure sensor based on the initial pressure data, initial temperature data, shock wave pressure data, and shock wave velocity data.

[0016] In the above-mentioned air free-field pressure sensor dynamic calibration system, the pressure and temperature of the initial state of the shock wave chamber are monitored through the pressure measurement module and the temperature measurement module, and it is determined whether the shock wave test conditions are met. When the shock wave test conditions are met, high-pressure gas is input; otherwise, monitoring continues.

[0017] In the above-mentioned air free field pressure sensor dynamic calibration system, the shock wave test conditions are:

[0018] The temperature is 15-25℃; the pressure is 90-106kPa.

[0019] In the above-mentioned air free-field pressure sensor dynamic calibration system, the signal conditioner adjusts the voltage of the shock wave pressure data to within 10V to obtain recognizable shock wave pressure data.

[0020] In the above-mentioned air free-field pressure sensor dynamic calibration system, the shock wave velocity is 1.5 Mach.

[0021] In the above-mentioned air free-field pressure sensor dynamic calibration system, the shock wave chamber includes a high-pressure chamber, a low-pressure chamber, a diaphragm and two flanges;

[0022] The high-pressure chamber and the low-pressure chamber are both column structures; one end of the high-pressure chamber is horizontally coaxially connected with one end of the low-pressure chamber; the diaphragm is installed at the connection between the high-pressure chamber and the low-pressure chamber; a flange is installed at the other end of the high-pressure chamber and the other end of the low-pressure chamber respectively to achieve sealing.

[0023] In the above-mentioned dynamic calibration system for an air free-field pressure sensor, the pressure source is connected to a flange at one end of the high-pressure chamber to input high-pressure gas into the inner cavity of the high-pressure chamber.

[0024] In the above-mentioned air free-field pressure sensor dynamic calibration system, the diaphragm is made of aluminum material; it realizes the isolation of the high-pressure chamber and the low-pressure chamber; when the pressure in the high-pressure chamber continues to increase, it breaks through the diaphragm and enters the low-pressure chamber, generating a gas shock wave in the low-pressure chamber.

[0025] In the above-mentioned air free-field pressure sensor dynamic calibration system, the air free-field pressure sensor is connected to a flange at one end of the low-pressure chamber.

[0026] In the above-mentioned dynamic calibration system for an air free-field pressure sensor, the maximum pressure borne by the inner cavity of the high-pressure chamber is 0.01-7MPa, the corresponding diaphragm thickness is 0.075-3mm, and the corresponding pressure measurement range of the air free-field pressure sensor is 0.1-13MPa.

[0027] The beneficial effects of the present invention compared with the prior art are:

[0028] (1) The air free field pressure sensor dynamic calibration method of the present invention can realize the dynamic calibration of the air free field pressure sensor under a preset reflection step pressure;

[0029] (2) The present invention solves the problem of tracing the dynamic characteristic value of air free-field pressure sensors, and provides more reliable measurement guarantee for air free-field pressure sensors widely used in aviation, aerospace, shipbuilding, civil blasting and other fields;

[0030] (3) The present invention greatly reduces the impact of vibration and shock during sensor calibration, and ensures the sealing of the sensor during dynamic calibration; the sensitive surface of the air free field pressure sensor is installed flush with the shock wave surface, and then placed at the end of the shock tube; according to the size of the step pressure, the shock tube diaphragm is selected and installed. The high pressure chamber of the shock tube is pressurized to generate shock waves by natural membrane rupture; the output response curve of the air free field pressure sensor is measured, and the dynamic indicators such as the resonant frequency, rise time, and sensitivity are measured, thereby achieving the purpose of dynamic calibration of the air free field pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the dynamic calibration system of the air free-field pressure sensor of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the embodiments.

[0033] The present invention provides an air free-field pressure sensor dynamic calibration system, which provides dynamic calibration for air free-field pressure sensors within a pressure range of (0.01-7) MPa, aiming to solve the problem of tracing the value of air free-field dynamic pressure applicable to aerospace, aviation, civil and other fields.

[0034] The present invention provides a calibration scheme and process. In order to reliably calibrate the air free field pressure sensor dynamically, the following two issues need to be considered and resolved: a) the air free field pressure sensor has a special structure and needs to design a dedicated installation tool; b) dynamic calibration is carried out to analyze the difference between free field pressure calibration and reflected step pressure calibration.

[0035] Air free field pressure sensor dynamic calibration system, such as Figure 1 As shown, it specifically includes a shock wave chamber, a pressure control console, a pressure source, an air free field pressure sensor, a signal conditioner, a pressure measurement module, a temperature measurement module, a speed measurement system, a data acquisition and analysis system and an output device.

[0036] The shock wave chamber is axially arranged horizontally; an air free field pressure sensor, a signal conditioner, a pressure measuring module, a temperature measuring module and a speed measuring system are all arranged on the shock wave chamber.

[0037] Pressure measurement module: measures the initial state pressure of the shock wave chamber; and transmits the initial pressure data to the data acquisition and analysis system.

[0038] Temperature measurement module: measures the initial temperature of the shock wave chamber; and transmits the initial temperature data to the data acquisition and analysis system.

[0039] Pressure control console: controls the pressure source to input high-pressure gas into the shock wave chamber to generate gas shock waves.

[0040] Air free field pressure sensor: It measures the gas shock wave pressure in the shock wave chamber and transmits the shock wave pressure data to the signal conditioner.

[0041] Signal conditioner: Receives shock wave pressure data from the air free field pressure sensor; performs voltage adjustment on the shock wave pressure data to generate recognizable shock wave pressure data, and sends the recognizable shock wave pressure data to the data acquisition and analysis system.

[0042] Velocity measurement system: measures the velocity of the gas shock wave and sends the shock wave velocity data to the data acquisition and analysis system.

[0043] Data acquisition and analysis system: receives initial pressure data from the pressure measurement module; receives initial temperature data from the temperature measurement module; receives identifiable shock wave pressure data from the signal conditioner; receives shock wave velocity data from the velocity measurement system; sends initial pressure data, initial temperature data, shock wave pressure data, and shock wave velocity data to the output device.

[0044] Output device: Receives initial pressure data, initial temperature data, shock wave pressure data, and shock wave velocity data from the data acquisition and analysis system, and calibrates the dynamic indicators of the air free field pressure sensor based on the initial pressure data, initial temperature data, shock wave pressure data, and shock wave velocity data.

[0045] The present invention monitors the pressure and temperature of the initial state of the shock wave chamber through a pressure measuring module and a temperature measuring module, and determines whether the shock wave test conditions are met. When the shock wave test conditions are met, high-pressure gas is input; otherwise, monitoring continues.

[0046] The shock wave test conditions are:

[0047] The temperature is 15-25℃; the pressure is 90-106kPa.

[0048] The signal conditioner adjusts the voltage of the shock wave pressure data to less than 10V to obtain recognizable shock wave pressure data. The shock wave speed is 1.5 Mach.

[0049] The specific design of the shock wave chamber is:

[0050] The shock wave chamber includes a high-pressure chamber, a low-pressure chamber, a diaphragm and two flanges. Both the high-pressure chamber and the low-pressure chamber are cylindrical structures; one end of the high-pressure chamber is horizontally coaxially connected to one end of the low-pressure chamber; the diaphragm is installed at the connection between the high-pressure chamber and the low-pressure chamber; a flange is installed at the other end of the high-pressure chamber and the other end of the low-pressure chamber to achieve sealing.

[0051] The pressure source is connected to a flange at one end of the high-pressure chamber to input high-pressure gas into the inner cavity of the high-pressure chamber.

[0052] The diaphragm is made of aluminum material; it realizes the separation of the high-pressure chamber and the low-pressure chamber; when the pressure in the high-pressure chamber continues to increase, it breaks through the diaphragm and enters the low-pressure chamber, generating a gas shock wave in the low-pressure chamber.

[0053] The air free-field pressure sensor is connected to the flange at one end of the low-pressure chamber.

[0054] The maximum pressure borne by the inner cavity of the high-pressure chamber is 0.01-7MPa, the corresponding diaphragm thickness is 0.075-3mm, and the corresponding pressure measurement range of the air free field pressure sensor is 0.1-13MPa.

[0055] The present invention utilizes a fluid finite element program to simulate and analyze the pressure field distribution in the shock tube, and compares the working conditions of the free field pressure and the reflected step pressure to obtain the difference between the two. According to the special structure of the air free field pressure sensor, a special installation tool is designed to greatly reduce the influence of vibration and shock during sensor calibration, and ensure the sealing of the sensor during dynamic calibration. The sensitive surface of the air free field pressure sensor is installed flush, facing the shock wave surface, and then placed at the end of the shock tube. According to the size of the step pressure, the shock tube diaphragm is selected and installed. Pressurize the high-pressure chamber of the shock tube, and generate shock waves by natural rupture of the membrane. The output response curve of the air free field pressure sensor is measured, and the dynamic indicators such as the resonant frequency, rise time, and sensitivity are measured, thereby achieving the purpose of dynamic calibration of the air free field pressure sensor.

[0056] The above method is used to perform dynamic calibration of the air free-field pressure sensor. The calibration results of dynamic indicators such as resonant frequency, rise time, sensitivity, etc. are highly consistent with the dynamic indicators of this type of pressure sensor given by advanced foreign manufacturers Kistler and PCB. The dynamic calibration method of the air free-field pressure sensor of the present invention can realize the dynamic calibration of the air free-field pressure sensor under a preset reflection step pressure. The pressure measurement range is (0.01~7)MPa, and the measurement uncertainty is U=2.2% (k=2). The invention can solve the problem of tracing the dynamic characteristic value of the air free-field pressure sensor, and provide more reliable measurement guarantee for the air free-field pressure sensor widely used in aviation, aerospace, shipbuilding, civil blasting and other fields.

[0057] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A dynamic calibration system for an air free-field pressure sensor, characterized in that: It includes a shock wave chamber, a pressure control console, a pressure source, an air free field pressure sensor, a signal conditioner, a pressure measurement module, a temperature measurement module, a speed measurement system, a data acquisition and analysis system, and an output device; The shock wave chamber is axially arranged horizontally; the air free field pressure sensor, signal conditioner, pressure measurement module, temperature measurement module and speed measurement system are all arranged on the shock wave chamber; Pressure measurement module: measures the initial pressure of the shock wave chamber and transmits the initial pressure data to the data acquisition and analysis system; Temperature measurement module: measures the initial temperature of the shock wave chamber and transmits the initial temperature data to the data acquisition and analysis system; Pressure control console: controls the pressure source to input high-pressure gas into the shock wave chamber to generate gas shock waves; Air free field pressure sensor: measures the gas shock wave pressure in the shock wave chamber and transmits the shock wave pressure data to the signal conditioner; Signal conditioner: receives shock wave pressure data from the air free field pressure sensor; performs voltage adjustment on the shock wave pressure data to generate recognizable shock wave pressure data, and sends the recognizable shock wave pressure data to the data acquisition and analysis system; Velocity measurement system: measures the velocity of gas shock waves and sends the shock wave velocity data to the data acquisition and analysis system; Data acquisition and analysis system: receiving the initial pressure data from the pressure measurement module; Receive initial temperature data from the temperature measurement module; receive identifiable shock wave pressure data from the signal conditioner; receive shock wave velocity data from the velocity measurement system; send initial pressure data, initial temperature data, shock wave pressure data, and shock wave velocity data to the output device; Output device: Receives initial pressure data, initial temperature data, shock wave pressure data, and shock wave velocity data from the data acquisition and analysis system, and calibrates the dynamic indicators of the air free-field pressure sensor based on the initial pressure data, initial temperature data, shock wave pressure data, and shock wave velocity data.

2. The air free-field pressure sensor dynamic calibration system according to claim 1, characterized in that: The pressure and temperature of the initial state of the shock wave chamber are monitored through the pressure measurement module and the temperature measurement module, and it is determined whether the shock wave test conditions are met. When the shock wave test conditions are met, high-pressure gas is input; otherwise, monitoring continues.

3. The air free-field pressure sensor dynamic calibration system according to claim 2, characterized in that: The shock wave test conditions are: The temperature is 15-25℃; the pressure is 90-106kPa.

4. The air free-field pressure sensor dynamic calibration system according to claim 1, characterized in that: The signal conditioner adjusts the voltage of the shock wave pressure data to within 10V to obtain recognizable shock wave pressure data.

5. The air free-field pressure sensor dynamic calibration system according to claim 1, characterized in that: The shock wave speed is 1.5 Mach.

6. The air free-field pressure sensor dynamic calibration system according to claim 1, characterized in that: The shock wave chamber comprises a high pressure chamber, a low pressure chamber, a diaphragm and two flanges; The high-pressure chamber and the low-pressure chamber are both column structures; one end of the high-pressure chamber is horizontally coaxially connected with one end of the low-pressure chamber; the diaphragm is installed at the connection between the high-pressure chamber and the low-pressure chamber; a flange is installed at the other end of the high-pressure chamber and the other end of the low-pressure chamber respectively to achieve sealing.

7. The air free-field pressure sensor dynamic calibration system according to claim 6, characterized in that: The pressure source is connected to a flange at one end of the high pressure chamber to input high pressure gas into the inner cavity of the high pressure chamber.

8. The air free-field pressure sensor dynamic calibration system according to claim 6, characterized in that: The diaphragm is made of aluminum material; it separates the high-pressure chamber from the low-pressure chamber; when the pressure in the high-pressure chamber increases continuously, it breaks through the diaphragm and enters the low-pressure chamber, generating a gas shock wave in the low-pressure chamber.

9. The air free-field pressure sensor dynamic calibration system according to claim 6, characterized in that: The air free field pressure sensor is communicated with a flange at one end of the low pressure chamber.

10. The air free-field pressure sensor dynamic calibration system according to claim 6, characterized in that: The maximum pressure borne by the inner cavity of the high-pressure chamber is 0.01-7MPa, the corresponding thickness of the diaphragm is 0.075-3mm, and the corresponding pressure measuring range of the air free field pressure sensor is 0.1-13MPa.

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