A temperature sensor dynamic response characteristic parameter measuring device and method

Abstract

The application discloses a kind of temperature sensor dynamic response characteristic parameter measuring device and method, belong to temperature measurement technical field, measuring device includes convection environment and control unit, and with the displacement sensor and electromagnetic ejection device of control unit connection;The electromagnetic ejection device includes guide rail and conductive slider, conductive slider is slidably connected with guide rail, and conductive slider is used to connect the temperature sensor to be measured, and the temperature sensor to be measured is directly opposite the measuring hole of convection environment, and conductive slider can be moved to the measuring hole of convection environment under electromagnetic action;The displacement sensor is set on the edge of the measuring hole of convection environment, for obtaining the time of the temperature measuring end of the temperature sensor to be measured enters convection environment, and the temperature sensor to be measured is connected with control unit;Environment control device is arranged in the convection environment, for regulating the environmental parameter of convection environment;The measuring device can accurately determine the dynamic response characteristic parameter of temperature sensor, and help sensor selection in practical application.

Description

Technical Field

[0001] This invention relates to the field of temperature measurement technology, specifically to a device and method for measuring the dynamic response characteristic parameters of a temperature sensor. Background Technology

[0002] Temperature measurement and control are widely used in industrial production and daily life, and are essential for the safe and efficient operation of equipment. Contact temperature measurement is the most common method, with thermocouples and resistance temperature detectors (RTDs) being the two main types of sensors. In transient temperature measurement, the sensor's sensing junction or element needs a certain amount of time to reach thermal equilibrium, therefore it cannot immediately reflect the measured temperature, resulting in a discrepancy between the measured and actual temperatures. The dynamic response characteristics of temperature sensors mainly include thermal response time and time constant. These parameters are influenced by the sensor's materials, structure, and the measurement environment, making accurate theoretical calculations difficult; they are often obtained through experimental determination. Clearly understanding the dynamic response characteristics of a temperature sensor is crucial for selecting a suitable sensor in temperature testing systems such as those operating in alternating temperature fields, ensuring that its dynamic response performance meets design and usage requirements, and achieving rapid and accurate temperature measurement.

[0003] Traditional methods for testing the dynamic response characteristics of temperature sensors often employ lasers or high-temperature blackbody furnaces to create temperature steps. For positive temperature steps, the boundary conditions created are radiative boundary conditions, which are rarely seen in practical engineering applications. In practice, convective boundary conditions are more common, making the test results difficult to reference. Furthermore, the excitation source is singular; if a similar medium is not used in practical applications, the test results are worthless, and the testing cost is high. Some testing methods use convective boundary conditions, but the temperature sensor cannot be quickly deployed to the test environment, resulting in large testing errors. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a device and method for measuring the dynamic response characteristic parameters of a temperature sensor, which can quickly and accurately measure the dynamic response characteristic parameters of a temperature sensor.

[0005] This invention is achieved through the following technical solution:

[0006] In a first aspect, this application provides a device for measuring the dynamic response characteristic parameters of a temperature sensor, including a convection environment and a control unit, as well as a displacement sensor and an electromagnetic ejection device connected to the control unit;

[0007] The electromagnetic catapult includes a guide rail and a conductive slider. The conductive slider is slidably connected to the guide rail. The conductive slider is used to connect the temperature sensor to be measured, and the temperature sensor to be measured is facing the measuring hole of the convection environment. The conductive slider can move towards the measuring hole of the convection environment under electromagnetic action.

[0008] The displacement sensor is set at the edge of the measuring hole in the convection environment to obtain the moment when the measuring end of the temperature sensor under test enters the convection environment. The temperature sensor under test is connected to the control unit.

[0009] An environmental control device is installed in the convective environment to regulate the environmental parameters of the convective environment.

[0010] Preferably, the guide rail is vertically mounted on the support platform, the conductive slider is connected to the guide rail groove, and the center of the conductive slider is provided with a fixing hole for fixing the temperature sensor to be measured.

[0011] The vertical guide rail, conductive slider, high-frequency AC power supply, and switch are connected in series, and the switch is connected to the control unit.

[0012] Preferably, the convection environment is an airflow environment and a liquid flow environment.

[0013] Preferably, the airflow environment includes a wind tunnel, and the environmental control device corresponding to the airflow environment includes a fan, a heat source, and a temperature control device;

[0014] The fan is connected to the wind tunnel, which creates airflow inside the wind tunnel. A heat source is placed in the airflow circulation channel to heat the airflow in the wind tunnel. The heat source is connected to a temperature control device. The measuring hole is placed on the surface of the wind tunnel, and the displacement sensor is placed on the surface of the wind tunnel.

[0015] Preferably, the wind tunnel is also equipped with a labeled temperature sensor and a hot-wire anemometer.

[0016] Preferably, the liquid flow environment includes a water tank, and the environmental control device corresponding to the liquid flow includes a stirring device, a heater, and a temperature controller;

[0017] The stirring device and heater are installed in the water tank, and the temperature controller is connected to the heater.

[0018] The top of the water tank is provided with a cover plate, a measuring hole is provided on the cover plate, and a displacement sensor is provided on the cover plate and located at the edge of the measuring hole.

[0019] Preferably, the water tank is also equipped with a Pitot tube, which is connected to a differential pressure transmitter.

[0020] Preferably, the opening of the measuring hole is provided with a heat shield, and a one-way valve is provided in the heat shield.

[0021] Preferably, the heat shield is a tapered nozzle that extends from bottom to top;

[0022] The one-way valve includes a fixed ring disposed in a converging nozzle. The lower end of the fixed ring is provided with multiple flexible diaphragms. The upper end of the diaphragms is connected to the lower edge of the fixed ring. The lower end of the diaphragms is inclined towards the axis of the fixed ring, and the lower ends of the multiple diaphragms abut against each other.

[0023] Secondly, this application provides a measurement method for a temperature sensor dynamic response characteristic parameter measuring device, including:

[0024] The control unit obtains the time corresponding to the percentage of the ambient temperature step change that the temperature sensor reaches at the sensing end, and uses this as the end time. The moment when the temperature sensor's sensing end enters the convective environment is used as the initial time. Based on the initial and final times, the dynamic response characteristic parameters of the temperature sensor under test are determined.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] This application provides a device for measuring the dynamic response characteristic parameters of a temperature sensor. It utilizes high-frequency alternating current to generate an alternating magnetic field around a guide rail. When current flows through the conductive slider, based on the principle of electromagnetic induction (Lorentz force principle), the current experiences a force in the magnetic field, propelling the conductive slider to accelerate along the guide rail. The conductive slider is connected to the temperature sensor under test. Therefore, when the conductive slider is ejected, the temperature sensor is also rapidly deployed into the convection environment. This ejection method significantly shortens the time from the temperature sensor's sensing end contacting the convection environment to its complete entry into the environment, achieving instantaneous entry and reducing the duration of the temperature step process, thereby reducing measurement errors. Furthermore, a displacement sensor is placed at the entrance of the convection environment to accurately obtain the moment (initial moment) when the temperature sensor's sensing end enters the convection environment. Accurate acquisition of this moment improves measurement accuracy. Secondly, this application provides two types of convection environments: an airflow environment and a water flow environment. The temperature and flow rate parameters of the convection environment can be precisely controlled by a control unit to ensure the stability and consistency of the test conditions. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the low-speed airflow test environment for the present invention.

[0029] Figure 2 This is a schematic diagram of the low-speed water flow test environment for the present invention.

[0030] Figure 3 This is a flowchart of the testing method of the present invention.

[0031] In the diagram: 1. Wind tunnel; 2. Frequency converter; 3. Fan; 4. Heating grid; 5. Voltage regulator; 6. Hot-wire anemometer; 7. Heat shield; 8. High-power electric heating ring; 9. Conductive slider; 10. Temperature sensor; 11. Vertical guide rail; 12. Support platform; 13. Data acquisition card; 14. Desktop digital multimeter; 15. Computer; 16. Water tank; 17. Low-power electric heating rod; 18. Thermostat; 19. Motor; 20. Stirring rod; 21. Pitot tube; 22. Bracket; 23. Rosemount differential pressure transmitter; 24. First DC power supply; 25. Second DC power supply; 26. Cover plate; 27. Standard temperature sensor; 28. First position sensor; 29. ​​Second position sensor; 30. High-frequency AC power supply; 31. Switch. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0034] Traditional testing methods for the dynamic response characteristic parameters of existing temperature sensors employ laser heating and high-temperature blackbody furnaces to establish step temperatures.

[0035] 1. The laser heating method utilizes a laser beam to rapidly heat a temperature sensor, causing a step change in the temperature it senses. The energy of the laser beam is absorbed by the sensor and converted into heat energy, thus generating a temperature step on the sensor. In the laser heating method, since the energy of the laser beam is transferred to the sensor in the form of radiation, the boundary condition is a radiation boundary condition, meaning that the heat exchange between the sensor and the laser beam mainly occurs through radiation.

[0036] 2. The high-temperature blackbody furnace method places the temperature sensor inside a high-temperature blackbody furnace, creating a temperature step by adjusting the furnace's temperature. A blackbody furnace can simulate an ideal radiation source, with its radiated energy proportional to the fourth power of its temperature. In this method, because the sensor is placed inside the furnace and surrounded by high-temperature radiation, the boundary conditions are also radiation-based. That is, heat exchange between the sensor and the blackbody furnace primarily occurs through radiation.

[0037] However, radiation boundary conditions are mostly used in theoretical measurement research, while convective boundary conditions are more common in practical engineering applications. Therefore, the measurement results of radiation boundary conditions cannot characterize the measurement results of convective boundary conditions. In existing convective environments, the temperature sensor is slow to be deployed to the environment under test, resulting in large measurement errors in the dynamic response characteristic parameters of the temperature sensor.

[0038] Based on the above problems, this application provides a device and method for measuring the dynamic response characteristic parameters of a temperature sensor, enabling accurate measurement of the dynamic response characteristic parameters of a temperature sensor in a fluid environment. The measuring device is described in detail below.

[0039] To facilitate understanding of the technical solution in this application, the technical names used in this solution will first be explained:

[0040] The dynamic response characteristic parameters of a temperature sensor mainly include thermal response time and time constant;

[0041] Thermal response time refers to the time required for the output of a temperature sensor to change to a specified percentage of the measured temperature when the temperature of the measured medium undergoes a step change. This time parameter reflects how quickly the temperature sensor detects the temperature of the measured medium and outputs an accurate signal.

[0042] The time constant refers to the time it takes for the temperature of the sensing part of the temperature sensor to reach a specified percentage of the ambient temperature step. The standard time is the time it takes for the temperature sensor output to change to 63.2% of the step temperature.

[0043] A device for measuring the dynamic response characteristic parameters of a temperature sensor includes a convection environment and a control unit, as well as a displacement sensor and an electromagnetic ejection device connected to the control unit.

[0044] The electromagnetic catapult includes a guide rail and a conductive slider. The conductive slider is slidably connected to the guide rail and is used to connect the temperature sensor to be measured. The temperature sensor to be measured is facing the inlet of the convection environment. The conductive slider can move towards the inlet of the convection environment under electromagnetic action.

[0045] When high-frequency alternating current is applied to the guide rail, an alternating magnetic field is generated around the guide rail. Current flows through the conductive slider. According to the principle of electromagnetic induction (or the Lorentz force principle), the current will be subjected to a force in the magnetic field. This force will push the conductive slider to accelerate along the guide rail, thereby achieving a catapult effect. This places the temperature sensing end of the temperature sensor under test into the convection environment, shortening the time from the temperature sensing end's initial contact with the convection environment to its complete entry into the convection environment. By switching on and off the electromagnetic catapult technology, the temperature sensor can instantly fall into the test environment, reducing the duration of the temperature step process and thus reducing measurement errors.

[0046] The displacement sensor is placed at the entrance of the convection environment to obtain the moment when the temperature measuring end of the temperature sensor under test enters the convection environment. The temperature sensor under test is connected to the control unit.

[0047] The convective environment refers to both airflow and water flow environments.

[0048] The control unit obtains the time corresponding to the percentage of the ambient temperature step change that the temperature sensing part of the temperature sensor reaches and uses it as the end time. The moment when the temperature sensing end of the temperature sensor enters the convective environment is used as the initial time. The control unit determines the dynamic response characteristic parameters of the temperature sensor under test based on the initial time and the end time.

[0049] Example 1

[0050] The following section uses an airflow environment as an example to describe in detail the above-mentioned device and method for measuring the dynamic response characteristic parameters of a temperature sensor. The measuring device includes an airflow environment, a second displacement sensor, an electromagnetic ejection device, and a control unit.

[0051] The airflow environment includes wind tunnel 1, fan 3, heat source and temperature control device;

[0052] A wind tunnel 1 has an airflow circulation channel. A heat source is set in the airflow circulation channel to heat the airflow in the wind tunnel 1. The heat source is connected to a temperature control device to adjust the temperature of the heat source, thereby controlling the temperature of the airflow in the wind tunnel. A fan 3 is connected to the wind tunnel to generate wind pressure in the wind tunnel, causing the airflow in the wind tunnel to move at a speed. A measuring hole is provided on the surface of the wind tunnel, and the temperature sensing end of the temperature sensor 10 to be measured enters the wind tunnel through the measuring hole.

[0053] During the measurement process, the sensing end of the temperature sensor 10 is located at the top of the measuring hole. The airflow overflowing through the measuring hole will affect the initial temperature of the sensing end. Therefore, a heat shield 7 is provided at the opening of the measuring hole. A one-way valve is provided in the heat shield 7. The sensing end of the temperature sensor 10 enters the wind tunnel through the one-way valve and the heat shield 7. The one-way valve can prevent the airflow in the wind tunnel from escaping, ensure the internal temperature of the wind tunnel is constant, and solve the problem of airflow escaping affecting the initial temperature of the sensing end, thus ensuring the accuracy of the measurement.

[0054] The heat shield 7 is a tapered nozzle installed on the measuring hole, which can effectively reduce radiative heat dissipation and increase the airflow velocity near the temperature sensing point, thereby increasing the convective heat transfer coefficient and reducing the test error from both aspects.

[0055] The one-way valve includes a fixed ring, and a plurality of flexible diaphragms are provided at the lower end of the fixed ring. The upper ends of the diaphragms are connected to the lower edge of the fixed ring, the lower ends of the diaphragms are inclined toward the axis of the fixed ring, and the lower ends of the plurality of diaphragms abut against each other.

[0056] For example, there are two flexible diaphragms arranged in a V-shape, and the side edges of the two flexible diaphragms are connected to each other. The one-way valve is set at the upper end (the smaller diameter end) of the heat shield 7 through a fixing ring, and the flexible diaphragm is located inside the measuring hole. In the initial state, the lower ends of the flexible diaphragms are in contact with each other to form a sealing structure to prevent the airflow in the wind tunnel from escaping. During the measurement process, the temperature sensing end of the temperature sensor to be measured extends through the two flexible diaphragms into the measuring section of the wind tunnel.

[0057] Any section of the annular wind tunnel 1 is designated as a measurement section, the diameter of which is smaller than the diameter of the rest of the area. The measuring holes and heat sources are both located in the measurement section.

[0058] In this embodiment, the fan 3 is embedded at the end of the wind tunnel measurement end. The fan 3 is connected to the frequency converter, which is connected to the control unit. The frequency converter controls the speed of the fan to realize the flow rate of the convective gas inside the wind tunnel. The heat source is the electric heating grid 4. The electric heating grid 4 is equipped with a measurement section and is connected to the pressure regulator 5. The pressure regulator 5 is used to control the temperature of the electric heating grid 4. The second displacement sensor 29 is set on the surface of the wind tunnel and located in the measurement hole area.

[0059] The wind tunnel's measurement section is also equipped with a hot-wire anemometer 6 and a standard temperature sensor 27, which are used to measure the airflow velocity and temperature inside the wind tunnel, respectively. Based on the measured values, the fan and electric heating grid are adjusted to create an ideal airflow environment.

[0060] The electromagnetic catapult device includes a conductive slider 9, a vertical guide rail 11, a third DC power supply 30, and a switch 31. The lower end of the vertical guide rail 11 is fixed to the support platform 12. The groove of the vertical guide rail 11 is equipped with ball bearings and coated with lubricating oil. The conductive slider 9 is connected to the vertical guide rail 11 through the groove. The sliding process of the conductive slider 9 along the vertical guide rail is a rolling friction process. The conductive slider 9 is provided with a fixing hole, and the temperature sensor to be measured is placed in the fixing hole, with the temperature sensing end of the temperature sensor located at the lower end.

[0061] It should be noted that the height of the support platform needs to be set reasonably so that the temperature sensing end of the temperature sensor is placed at a suitable height in the environment to be measured. At the same time, the support platform acts as a limiting device for the conductive slider 9, limiting the ejection distance of the conductive slider 9. The vertical guide rail 11, the conductive slider 9, the high-frequency AC power supply 30, and the switch 31 are connected in series. The switch 31 is connected to the control unit. When the switch 31 is closed, the alternating magnetic field generated by the vertical guide rail 11 causes current to flow through the conductive slider 9. Under the action of the magnetic field, the slider 9 is subjected to force and is instantly ejected electromagnetically along the vertical guide rail 11 into the environment to be measured.

[0062] The vertical guide rail has built-in ball bearings on the bottom surface and is coated with lubricating oil. As the conductive slider slides down along it, the back side experiences sliding friction, resulting in low friction and faster sliding speed. This facilitates instantaneous temperature jumps and reduces testing errors.

[0063] The control unit includes a data acquisition card 13, a desktop digital multimeter 14, and a computer 15; the second position sensor 29, the hot-wire anemometer 6, the temperature sensor to be measured 10, and the standard temperature sensor 27 are connected to the data acquisition card 13, which is built into the desktop digital multimeter 14 and connected to the computer 15.

[0064] The wind tunnel can generate wind speeds of 3 m / s and temperature gradients of 10-20°C. The airflow temperature can be adjusted from room temperature to 500°C depending on the actual application environment, and the airflow velocity can be adjusted from 0-30 m / s.

[0065] Example 2

[0066] The following section uses an airflow environment as an example to describe in detail the above-mentioned device and method for measuring the dynamic response characteristic parameters of a temperature sensor. The measuring device includes a liquid fluid environment, a first displacement sensor 28, an electromagnetic ejection device, and a control unit.

[0067] The difference between Embodiment 2 and Embodiment 1 lies in the convection environment. The electromagnetic catapult device and the control unit have the same structure. In this embodiment, the convection environment is a liquid fluid environment. The liquid fluid environment will be described in detail below.

[0068] The liquid fluid environment includes a water tank 16, a stirring device, a heater, and a temperature controller 18.

[0069] The water tank is fixed to a bracket 22 and has a cover plate 26 on top. The stirring device includes a stirring rod 20 and a motor 19. The stirring rod 20 extends into the water tank through the cover plate. The motor is connected to the stirring rod and to a second DC power supply 25. The stirring rod 20 and the motor 19 are fixed to the bracket 22. The stirring rod 20 is made of stainless steel and is a propeller-type stirrer. The cover plate has a measuring hole through which a temperature sensor is inserted into the fluid. A first position sensor 28 is mounted on the cover plate. The side wall of the water tank has a drain outlet, and the cover plate has a water inlet.

[0070] The cover plate can effectively eliminate the impact on the test data caused by the upward natural convection of hot air near the water tank, which would cause the sensor under test to sense the temperature change in advance.

[0071] A Pitot tube 21 is installed in the water tank, pointing towards the axis of the cylindrical water tank 16. The Pitot tube 21 is connected to the Rosemount differential pressure transmitter 23, which is connected to the first DC power supply 24. The Pitot tube 21 is fixed to the bracket 22 and located in the arc-shaped opening slot of the cover plate 26.

[0072] During testing, the temperature sensing end of the temperature sensor inside the water tank 16 has the same coordinates as the leading edge of the Pitot tube in the radial and vertical directions.

[0073] The heater is installed in the water tank to heat the fluid. The heater is connected to the thermostat 18. The temperature measuring end of the thermostat 18 extends into the water tank. The heater includes a low-power electric heating rod 17 and a high-power electric heating ring 8, which are immersed below the water surface of the water tank 16. The low-power electric heating rod 17 is connected to the plug of the thermostat 18.

[0074] The water flow environment can provide a flow rate of 0.4±0.05 m / s. If the temperature sensor to be measured is a thermocouple, a temperature step of 40-50℃ is used; if it is a resistance temperature detector (RTD), a temperature step of <10℃ is used. The second DC power supply 25 supplies power to the motor 19 of the stirring rod 20, and the water flow rate is controlled by adjusting the voltage of the second DC power supply 25. The water temperature can be adjusted within the range of 0-100℃ according to the actual application environment, and the water flow rate can be adjusted within the range of 0-2.2 m / s.

[0075] The measurement methods of Examples 1 and 2 are described below.

[0076] Step 1: Before measurement, adjust the two test environments to the target parameters;

[0077] In the low-speed airflow environment of Example 1, the frequency of the inverter 2 of the fan 3 is adjusted to stabilize the reading of the hot-wire anemometer 6 at 3 m / s. The voltage regulator 5 of the heating grid 4 is adjusted to change the heating power so that the temperature of the hot air is 10-20°C higher than the room temperature, that is, to produce a constant temperature step value within the range of 10-20°C.

[0078] In the low-speed water flow environment of Example 2, the voltage of the second DC power supply 25, which supplies power to the motor 19 of the stirring rod 20, is adjusted to approximately 8.0V, resulting in a reading of approximately 80Pa for the Rosemount differential pressure transmitter 23, indicating a water flow velocity of 0.4m / s. When testing thermocouples, the target temperature of the temperature controller 18 is set to be 40-50°C higher than the ambient temperature; when testing resistance temperature detectors (RTDs), the target temperature of the temperature controller 18 is set to be no more than 10°C higher than the ambient temperature. The high-power electric heating ring 8 initially heats the water rapidly. When the temperature approaches the set temperature, the high-power electric heating ring 8 is switched off, and a low-power electric heating rod 17 heats the water to the target temperature. During the test, if the water temperature drops below the target temperature due to heat dissipation, the low-power electric heating rod 17 automatically heats the water to maintain a constant temperature.

[0079] Using two sets of electric heating elements with different power can not only shorten the heating time, but also eliminate the disadvantage of high thermal inertia of high-power heating devices, which is conducive to more precise control of water temperature and stabilization at the target temperature.

[0080] Step 2: Connect one end of the temperature sensor 10 to the data acquisition card 13 and fix the other end to the opening position of the conductive slider 9. The conductive slider 9 is placed on the upper end of the vertical guide rail 11.

[0081] Step 3: Run the data acquisition program, and then close the switch 31 through the computer 15. The alternating magnetic field generated by the vertical guide rail 11 causes current to flow through the conductive slider 9. Under the action of the magnetic field, it is subjected to force and is instantly electromagnetically ejected along the vertical guide rail 11 into the test environment. The temperature sensor 10 in the hole of the conductive slider 9 instantly falls to the target height of the test environment. When the temperature sensor 10 falls to the appropriate height of the test environment, both ends of the conductive slider 9 fall on the support platform 12.

[0082] Step 4: Obtain the initial moment when the temperature sensor 10 falls into the environment to be measured based on the first displacement sensor and the second displacement sensor.

[0083] The computer 15 records the temperature information and corresponding times collected by the data acquisition card 13. Based on the measured data, the computer uses linear interpolation to obtain the time when the temperature of the sensing part of the temperature sensor 10 reaches a specified percentage of the ambient temperature step, which is taken as the final time. Based on the initial and final times, the dynamic response characteristic parameters of the temperature sensor 10 are calculated.

[0084] The temperature t corresponding to the time constant τc passes through =63.2% calculation, linear interpolation of the measured data to obtain the time corresponding to t, the time interval between the time and the initial time is the time constant.

[0085] Example 3

[0086] The test was conducted using a bare thermocouple of type K, with a sensing point diameter of 0.7 mm. The thermocouple leads were connected to H and L pins of channel 1 of the data acquisition card. The LabVIEW acquisition and display program was run.

[0087] The room temperature was 22.0℃, a low-speed airflow environment was used, and the selected temperature step was 13.0℃, heating the airflow to 35.0℃. The acquisition card's acquisition frequency was 14Hz. The thermocouple was instantly placed into the test environment, with the initial time being the 13th data point at 11:59:24. The thermocouple sensing point temperature reached 30.2℃, which is 63.2% of the excess temperature. The corresponding time was the 7th data point at 11:59:28. The calculated duration was 3.64s, meaning that under low-speed airflow and room temperature conditions, the thermocouple's time constant is 3.64s.

[0088] A low-speed water flow environment was used, with a room temperature of 20.4℃ and a temperature step of 44℃, i.e., heating the water to 64.4℃. When the thermocouple sensing point temperature was 57.4℃, the measured duration was 0.082s, meaning that the time constant of the thermocouple under low-speed water flow and room temperature conditions is 0.082s.

[0089] Example 4

[0090] The test was performed using a four-wire heating resistor with a Pt100 index. The two red wires were connected to the H pins of channels 1 and 11 of the data acquisition card, respectively, and the two white wires were connected to the L pins of channels 1 and 11 of the data acquisition card. The LabVIEW data acquisition and display program was then run.

[0091] When the frequency of inverter 2 of fan 3 is set to 24.2Hz, the reading of hot-wire anemometer 6 is stable at 3m / s. The room temperature is 20.3℃, a low-speed airflow environment is adopted, and the selected temperature step is 11.0℃, that is, heating the airflow to 31.3℃. The acquisition card's acquisition frequency is 14Hz. The thermocouple is instantly placed in the test environment. The initial time is the 9th data point at 9:57:03. The temperature of the thermocouple sensing point reaches 27.2℃, which is 63.2% of the excess temperature. The corresponding time is the 5th data point at 9:57:49. The calculated duration is 44.71s. That is, under the low-speed airflow and room temperature environment, the time constant of this Pt100 platinum resistance thermometer is 44.71s.

[0092] Using a low-speed water flow environment with a room temperature of 18.6℃ and a temperature step of 8.9℃ (i.e., heating water to 27.5℃), the resistance temperature reached 24.2℃, and the measured time was 3.71s. This means that the time constant of the Pt100 platinum resistance thermometer under low-speed water flow and room temperature conditions is 3.71s.

[0093] The temperature sensor dynamic response characteristic parameter measurement device provided in this application adopts the third type of boundary condition as the test environment and uses two test environments, airflow and water flow, which are applicable to most temperature measurement scenarios in actual engineering and the test results have higher reference value. By controlling the fluid parameters in the convection environment, the dynamic response performance test of the temperature sensor in the real medium, real temperature and flow rate of the use environment can be realized. It has practical value for engineering applications and is beneficial to the selection of sensors in practical applications.

[0094] In addition, this measuring device can not only test scenarios where the actual test environment is convective, but also scenarios where the actual test environment includes a large amount of radiative heat transfer. It converts the radiative heat transfer into convective heat transfer, obtains the total heat transfer coefficient based on the converted convective heat transfer coefficient, and then selects a suitable medium and flow rate to test the radiative-convective environment.

[0095] Secondly, this measuring device and method can also be applied to the teaching of "Heat Transfer," a core foundational course for majors such as Energy and Power Engineering, Nuclear Engineering, Aircraft Power Engineering, Process Equipment and Control Engineering, Building Environment, and Human Settlement Science and Technology. Heat conduction experiments are a crucial component of these courses. Currently, heat conduction experiments offered by domestic universities primarily focus on steady-state heat conduction, with relatively few non-steady-state experiments. Occasionally, some universities offer experiments using non-steady-state methods to measure thermal properties such as thermal conductivity. On the one hand, many practical engineering problems require determining the change of the internal temperature field of an object over time, or determining the time required for the internal temperature to reach a certain limit, necessitating the study of non-steady-state processes. Therefore, conducting more diverse non-steady-state heat conduction experiments is a necessary and practically valuable direction. On the other hand, the steady-state plate method for determining the thermal conductivity of insulating materials, currently offered by many universities, requires students to wait a considerable amount of time in class because the test must reach a steady state. Combining non-steady-state heat conduction experiments with alternating tests can not only reinforce knowledge points but also improve the utilization of class time. This measuring device effectively embodies the fundamental theory of unsteady-state heat conduction in heat transfer and applies a simplified method for analyzing simple unsteady-state heat conduction problems—the lumped parameter method. It creatively expands the unsteady-state heat conduction experiment and can be combined with steady-state heat conduction experiments for alternating testing. This not only improves the knowledge system of the experimental teaching of "Heat Transfer" but also effectively increases the utilization rate of class time.

[0096] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A temperature sensor dynamic response characteristic parameter measuring device, characterized by, The control unit is connected with a displacement sensor and an electromagnetic ejection device; The electromagnetic ejection device comprises a vertical guide rail and a conductive sliding block, the conductive sliding block is in sliding connection with the vertical guide rail, the conductive sliding block is used for connecting the temperature sensor to be measured, and the temperature sensor to be measured is opposite to a measuring hole of the convection environment, and the conductive sliding block can move to the measuring hole of the convection environment under the electromagnetic action; The displacement sensor is arranged at the edge of the measuring hole of the convection environment, and is used for acquiring the time when the temperature measuring end of the temperature sensor to be measured enters the convection environment, and the temperature sensor to be measured is connected with the control unit; The convection environment is provided with an environment control device for adjusting the environmental parameters of the convection environment; The vertical guide rail is arranged on a support platform, the conductive sliding block is connected with a sliding groove of the vertical guide rail, and the center of the conductive sliding block is provided with a fixing hole for fixing the temperature sensor to be measured; The vertical guide rail, the conductive sliding block, the high-frequency alternating current power supply and the switch are connected in series, and the switch is connected with the control unit; The support platform serves as a limiting device of the conductive sliding block, and limits the ejection distance of the conductive sliding block, the vertical guide rail, the conductive sliding block, the high-frequency alternating current power supply and the switch are connected in series, and the switch is connected with the control unit; when the switch is closed, the alternating magnetic field generated by the vertical guide rail, the current flows in the conductive sliding block, and the conductive sliding block is forced under the action of the magnetic field, and is ejected into the environment to be measured along the vertical guide rail in an instant; The mouth of the measuring hole is provided with a heat shield, and a one-way valve is arranged in the heat shield; The heat shield is a self-down tapered nozzle; The one-way valve comprises a fixed ring, the fixed ring is arranged in the tapered nozzle, a plurality of flexible diaphragms are arranged at the lower end of the fixed ring, the upper ends of the diaphragms are connected with the lower end edge of the fixed ring, the lower ends of the diaphragms are inclined to the axial direction of the fixed ring, and the lower ends of the plurality of diaphragms abut against each other.

2. The temperature sensor dynamic response characteristic parameter measuring device according to claim 1, characterized in that, The convection environment is a gas flow environment and a liquid flow environment.

3. The temperature sensor dynamic response characteristic parameter measuring device according to claim 2, characterized in that, The gas flow environment comprises a wind tunnel, and the corresponding environmental control device of the gas flow environment comprises a fan, a heat source and a temperature control device; The fan is connected with the wind tunnel, so that the inside of the wind tunnel forms an air flow, the heat source is arranged in an air circulation channel, the heat source is used for heating the air flow in the wind tunnel, the heat source is connected with the temperature control device, the measuring hole is arranged on the surface of the wind tunnel, and the displacement sensor is arranged on the surface of the wind tunnel.

4. The temperature sensor dynamic response characteristic parameter measuring device according to claim 3, characterized in that, The wind tunnel is also provided with a labeled temperature sensor and a hot-wire anemometer.

5. The apparatus of claim 2, wherein The liquid flow environment comprises a water tank, and the corresponding environmental control device of the liquid flow comprises a stirring device, a heater and a temperature controller; The stirring device and the heater are arranged in the water tank, and the temperature controller is connected with the heater; The top of the water tank is provided with a cover plate, the measuring hole is arranged on the cover plate, and the displacement sensor is arranged on the cover plate and located at the edge of the measuring hole.

6. The temperature sensor dynamic response characteristic parameter measuring device according to claim 5, characterized in that, The water tank is also provided with a Pitot tube, and the Pitot tube is connected with a differential pressure transmitter.

7. A measuring method of a temperature sensor dynamic response characteristic parameter measuring device according to any one of claims 1 to 6, characterized in that, The control unit acquires the time corresponding to the percentage of the temperature step amount of the temperature sensor when the temperature step amount reaches the environmental temperature, and regards the time as the final time, regards the time when the temperature measuring end enters the convection environment as the initial time, and determines the dynamic response characteristic parameter of the temperature sensor to be measured according to the initial time and the final time. ​

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