Device and method for measuring dynamic response characteristic parameters of temperature sensor

Abstract

The invention discloses a device and a method for measuring dynamic response characteristic parameters of a temperature sensor, and belongs to the technical field of temperature measurement. The measuring device comprises a convection environment, a control unit, and a displacement sensor and an electromagnetic ejection device which are connected with the control unit; the electromagnetic ejection device comprises a guide rail and a conductive sliding block, the conductive sliding block is in sliding connection with the guide rail, the conductive sliding block is used for being connected with a to-be-tested temperature sensor, the to-be-tested temperature sensor directly faces the measuring hole of the convection environment, and the conductive sliding block can move towards the measuring hole of the convection environment under the electromagnetic action; the displacement sensor is arranged at the edge of a measuring hole of the convective environment and used for acquiring the moment when the temperature measuring end of the temperature sensor to be measured enters the convective environment, and the temperature sensor to be measured is connected with the control unit; an environment control device is arranged in the convection environment and is used for regulating and controlling environment parameters of the convection environment; the measuring device can accurately determine the dynamic response characteristic parameters of the temperature sensor, and facilitates sensor model selection in practical application.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measurement, and in particular to a device and method for measuring dynamic response characteristic parameters of a temperature sensor. Background Art

[0002] Temperature measurement and control are widely used in industrial production and life, and are important conditions for the safe and efficient operation of equipment. Contact temperature measurement is the most common, and commonly used sensors are mainly thermocouples and thermal resistors. In the process of transient temperature measurement, the sensor temperature sensing node or temperature sensing element takes a certain amount of time to reach thermal equilibrium, so it cannot immediately respond to the temperature to be measured, and there is a certain difference between the measured temperature and the actual temperature to be measured. The dynamic response characteristic parameters of the temperature sensor mainly include thermal response time and time constant. The dynamic response characteristic parameters of the temperature sensor are affected by the material, structural form and temperature measurement environment of the temperature sensor. It is difficult to obtain accurate values ​​through theoretical calculations, and they are often obtained through experimental determination methods. Clarifying the dynamic response characteristics of the temperature sensor is crucial to selecting a suitable temperature sensor in temperature test systems such as alternating temperature fields, so as to ensure that its dynamic response performance indicators meet the design and use requirements and achieve the purpose of fast and accurate temperature measurement.

[0003] The traditional test methods for the dynamic response characteristic parameters of temperature sensors mostly use lasers or high-temperature blackbody furnaces to create step temperatures. For positive temperature steps, the boundary conditions created are radiation boundary conditions, which are relatively rare in actual engineering applications. In actual applications, they are mostly convection boundary conditions, making it difficult to refer to their test results. In addition, the excitation source is single, and if the same medium is not used in actual applications, the test results have no reference value, and the test cost is high. Some test methods also use convection boundary conditions, but the speed at which the temperature sensor is put into the test environment is not fast enough, resulting in large test errors. Summary of the invention In view of the problems existing in the prior art, the present invention provides a device and method for measuring dynamic response characteristic parameters of a temperature sensor, which can quickly and accurately measure the dynamic response characteristic parameters of the temperature sensor.

[0004] The present invention is achieved through the following technical solutions: In a first aspect, the present application provides a device for measuring characteristic parameters of dynamic response of a temperature sensor, comprising a convection environment and a control unit, and a displacement sensor and an electromagnetic ejection device connected to the control unit; The electromagnetic ejection device 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, and the conductive slider can move toward the measuring hole of the convection environment under the action of the electromagnetic force; The displacement sensor is arranged at the edge of the measuring hole of the convection environment, and is used to obtain the moment 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 to the control unit; An environment control device is provided in the convection environment for adjusting and controlling the environmental parameters of the convection environment.

[0005] Preferably, the guide rail is vertically arranged on the support platform, the conductive slider is connected to the slide groove of the guide rail, and a fixing hole for fixing the temperature sensor to be measured is arranged at the center of the conductive slider; The vertical guide rail, the conductive slider, the high-frequency AC power supply and the switch are connected in series, and the switch is connected to the control unit.

[0006] Preferably, the convection environment is an air flow environment and a liquid flow environment.

[0007] Preferably, the airflow environment includes a wind tunnel, and the environment control device corresponding to the airflow environment includes a fan, a heat source and a temperature control device; The fan is connected to the wind tunnel to form airflow inside the wind tunnel. The heat source is arranged in the airflow circulation channel. The heat source is used to heat the airflow in the wind tunnel. The heat source is connected to 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.

[0008] Preferably, the wind tunnel is also provided with a marked temperature sensor and a hot wire anemometer.

[0009] Preferably, the liquid flow environment includes a water tank, and the environment control device corresponding to the liquid flow includes 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 to the heater; A cover plate is arranged on the top of the water tank, a measuring hole is arranged on the cover plate, and a displacement sensor is arranged on the cover plate and located at the edge of the measuring hole.

[0010] Preferably, a Pitot tube is also provided in the water tank, and the Pitot tube is connected to the differential pressure transmitter.

[0011] Preferably, a heat shield is provided at the mouth of the measuring hole, and a one-way valve is provided in the heat shield.

[0012] Preferably, the heat shield is a nozzle that converges from bottom to top; The one-way valve includes a fixed ring, which is arranged in the tapered nozzle. A plurality of flexible diaphragms are arranged at the lower end of the fixed ring. The upper end of the diaphragm is connected to the lower edge of the fixed ring. The lower end of the diaphragm is inclined toward the axial direction of the fixed ring, and the lower ends of the plurality of diaphragms abut against each other.

[0013] In a second aspect, the present application provides a method for measuring a temperature sensor dynamic response characteristic parameter measuring device, comprising: The control unit obtains the time when the temperature of the temperature sensing end of the temperature sensor reaches the percentage of the ambient temperature step amount set and takes it as the final moment, and takes the moment when the temperature sensing end of the temperature sensor enters the convection environment as the initial moment, and determines the dynamic response characteristic parameters of the temperature sensor to be measured based on the initial moment and the final moment.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: The present application provides a temperature sensor dynamic response characteristic parameter measurement device, which uses high-frequency alternating current to generate an alternating magnetic field around the guide rail. After the current passes through the conductive slider, according to the principle of electromagnetic induction (the principle of Lorentz force), the current is acted upon by force in the magnetic field, pushing the conductive slider to accelerate along the guide rail. The conductive slider is connected to the temperature sensor to be measured, so when the conductive slider is ejected, the temperature sensor is also quickly thrown into the convection environment. The ejection method greatly shortens the time from the temperature sensing end of the temperature sensor contacting the convection environment to the time from the temperature sensing end completely entering the convection environment, realizes the instantaneous entry of the temperature sensor, reduces the duration of the temperature step process, and thus reduces the measurement error. In addition, the displacement sensor is set at the entrance of the convection environment to accurately obtain the moment (initial moment) when the temperature sensing end of the temperature sensor to be measured enters the convection environment. The accurate acquisition of this moment can improve the measurement accuracy; secondly, the present application provides two convection environments, namely, air flow environment or water flow environment, and the parameters such as temperature and flow rate of the convection environment can be accurately controlled by the control unit to ensure the stability and consistency of the test conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a schematic diagram of the low-speed airflow test environment test of the present invention.

[0017] Figure 2 It is a schematic diagram of the low-speed water flow test environment test of the present invention.

[0018] Figure 3 Flow chart of the testing method of the present invention.

[0019] In the figure: 1. Wind tunnel; 2. Frequency converter; 3. Fan; 4. Electric 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. Sink; 17. Low-power electric heating rod; 18. Temperature controller; 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; 27. Standard temperature sensor; 28. First position sensor; 29. ​​Second position sensor; 30. High-frequency AC power supply; 31. Switch. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0022] The traditional test method for the existing dynamic response characteristic parameters of temperature sensors uses laser heating and a high-temperature blackbody furnace to establish a step temperature.

[0023] 1. The laser heating method uses a laser beam to quickly heat the 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, thereby generating a temperature step on the sensor. In the laser heating method, since the energy of the laser beam is transmitted to the sensor in the form of radiation, the boundary condition is a radiation boundary condition, that is, the heat exchange between the sensor and the laser beam is mainly carried out through radiation.

[0024] 2. The high-temperature blackbody furnace method places the temperature sensor in a high-temperature blackbody furnace and creates a temperature step by adjusting the temperature of the blackbody furnace. The blackbody furnace can simulate an ideal radiation source, and its radiation energy is proportional to the fourth power of the temperature. In the high-temperature blackbody furnace method, since the sensor is placed in the blackbody furnace and is surrounded by high-temperature radiation, the boundary conditions are also radiation boundary conditions. That is, the heat exchange between the sensor and the blackbody furnace is also mainly carried out through radiation.

[0025] However, radiation boundary conditions are mostly used in theoretical measurement research, while in actual engineering applications, they are mostly convection boundary conditions. Therefore, the measurement results of radiation boundary conditions cannot represent the measurement results of convection boundary conditions. In the existing convection environment, since the speed at which the temperature sensor is put into the test environment is relatively slow, the measurement error of the dynamic response characteristic parameters of the temperature sensor is large.

[0026] Based on the above problems, the present application provides a device and method for measuring the dynamic response characteristic parameters of a temperature sensor, so as to accurately measure the dynamic response characteristic parameters of the temperature sensor in a fluid environment. The measuring device is described in detail below.

[0027] In order to facilitate the technical solution of this application, the technical names in the technical solution are first explained: The dynamic response characteristic parameters of the temperature sensor mainly include thermal response time and time constant; Thermal response time refers to the time required for the output of the temperature sensor to change to a certain percentage of the measured step temperature when the temperature of the measured medium changes step by step. This time parameter reflects how fast the temperature sensor detects the temperature of the measured medium and outputs an accurate signal.

[0028] The time constant refers to the time it takes for the temperature of the temperature 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.

[0029] A device for measuring dynamic response characteristic parameters of a temperature sensor comprises a convection environment and a control unit, and a displacement sensor and an electromagnetic ejection device connected to the control unit.

[0030] The electromagnetic ejection device includes a guide rail and a conductive slider, which is slidably connected to the guide rail. The conductive slider is used to connect a temperature sensor to be measured, and the temperature sensor to be measured is facing the entrance of the convection environment. The conductive slider can move toward the entrance of the convection environment under electromagnetic action.

[0031] When high-frequency alternating current is passed through the guide rail, an alternating magnetic field is generated around the guide rail, and current passes through the inside of the conductive slider. According to the principle of electromagnetic induction (or the Lorentz force principle), the current is acted upon by a force in the magnetic field, and this force pushes the conductive slider to accelerate along the guide rail, thereby achieving a catapult effect, and placing the temperature sensing end of the temperature sensor to be measured into a convection environment, shortening the time from the temperature sensing end contacting the convection environment to the time it completely enters the convection environment. The temperature sensor is instantly placed in the environment to be measured through the on-off electromagnetic catapult technology, reducing the duration of the temperature step process and thereby reducing the measurement error.

[0032] The displacement sensor is arranged at the entrance of the convection environment, and is used to obtain the moment when the temperature measuring end of the temperature sensor to be measured enters the convection environment. The temperature sensor to be measured is connected to the control unit.

[0033] The convection environment is an air flow environment and a water flow environment.

[0034] The control unit obtains the time when the temperature of the temperature sensing part of the temperature sensor reaches the percentage of the ambient temperature step amount set and takes it as the final moment, and takes the moment when the temperature measuring end of the temperature sensor enters the convection environment as the initial moment. The control unit determines the dynamic response characteristic parameters of the temperature sensor to be measured based on the initial moment and the final moment.

[0035] Example 1 Taking the airflow environment as an example, the above-mentioned device and method for measuring the dynamic response characteristic parameters of a temperature sensor are described in detail below. The measuring device includes an airflow environment, a second displacement sensor, an electromagnetic ejection device and a control unit.

[0036] The airflow environment includes a wind tunnel 1, a fan 3, a heat source and a temperature control device; An airflow circulation channel is formed in the wind tunnel 1, and a heat source is arranged in the airflow circulation channel. The heat source is used to heat the airflow in the wind tunnel 1. The heat source is connected to a temperature control device, and the temperature control device is used to adjust the temperature of the heat source, thereby controlling the temperature of the airflow in the wind tunnel. The fan 3 is connected to the wind tunnel to generate wind pressure in the wind tunnel, so that the airflow in the wind tunnel produces a moving flow rate. A measuring hole is arranged 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.

[0037] During the measurement process, the temperature sensing end of the temperature sensor 10 to be measured is located at the top of the measuring hole. The airflow overflowing through the measuring hole will affect the initial temperature of the temperature sensing end. Therefore, a heat shield 7 is provided at the mouth of the measuring hole. A one-way valve is provided in the heat shield 7. The temperature sensing end of the temperature sensor 10 to be measured enters the wind tunnel through the one-way valve and the heat shield 7. The one-way valve can prevent the airflow of the wind tunnel from escaping, thereby ensuring the constant internal temperature of the wind tunnel. At the same time, it solves the problem of airflow escaping affecting the initial temperature of the temperature sensing end, thereby ensuring the accuracy of the measurement.

[0038] The heat shield 7 is a tapered nozzle and is arranged on the measuring hole, which can effectively reduce radiation heat dissipation and increase the air flow velocity near the temperature sensing point, thereby increasing the convective heat transfer coefficient, thereby reducing the test error from two aspects.

[0039] The one-way valve includes a fixed ring, a plurality of flexible diaphragms are arranged at the lower end of the fixed ring, the upper end of the diaphragm is connected to the lower edge of the fixed ring, the lower end of the diaphragm is inclined toward the axial direction of the fixed ring, and the lower ends of the plurality of diaphragms abut against each other.

[0040] For example, the flexible diaphragm is composed of two pieces, the two flexible diaphragms are arranged in a V shape, and the side edges of the two flexible diaphragms are connected to each other. The one-way valve is arranged at the upper end (the end with a smaller diameter) 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 contact 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 passes through the two flexible diaphragms and extends into the measuring section of the wind tunnel.

[0041] Any section of the annular wind tunnel 1 is set as a measuring section, the diameter of the measuring section is smaller than the diameter of the remaining areas, and the measuring holes and the heat source are both arranged in the measuring section.

[0042] In this embodiment, the fan 3 is embedded in the end of the wind tunnel measuring end, the fan 3 is connected to the frequency converter, the frequency converter is connected to the control unit, and the speed of the fan is controlled by the frequency converter 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 provided with a measuring section and is connected to the voltage regulator 5, the voltage regulator 5 is used to control the temperature of the electric heating grid 4, and the second displacement sensor 29 is arranged on the surface of the wind tunnel and is located in the measuring hole area.

[0043] The measuring section of the wind tunnel is also provided with a hot wire anemometer 6 and a standard temperature sensor 27, which are used to measure the velocity and temperature of the airflow inside the wind tunnel respectively, and the fan and the electric heating grid are regulated according to the measured values ​​to construct an ideal airflow environment.

[0044] The electromagnetic ejection 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 on the support platform 12, a ball bearing is arranged in the slide groove of the vertical guide rail 11 and lubricating oil is applied, the conductive slider 9 is connected to the vertical guide rail 11 in the slide groove, the sliding process of the conductive slider 9 along the vertical guide rail is rolling friction, a fixing hole is arranged in the conductive slider 9, a temperature sensor to be measured is arranged in the fixing hole, and the temperature sensing end of the temperature sensor to be measured is located at the lower end.

[0045] 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 of the environment to be tested. At the same time, the support platform serves as a limiting device for the conductive slider 9 to limit the ejection distance of the conductive slider 9. The vertical guide rail 11 and the conductive slider 9, the high-frequency AC power supply 30, and the switch 31 are connected in series, and the switch 31 is connected to the control unit; when the switch 31 is closed, the vertical guide rail 11 generates an alternating magnetic field, and current flows through the conductive slider 9. The conductive slider 9 is subjected to force under the action of the magnetic field and is instantly electromagnetically ejected along the vertical guide rail 11 into the environment to be tested.

[0046] The bottom surface of the vertical guide groove is equipped with built-in balls and lubricating oil. When the conductive slider slides along it, the back side is in sliding friction, which has small friction and faster sliding speed, which is conducive to achieving instantaneous temperature steps and reducing test errors.

[0047] 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, the data acquisition card 13 is built into the desktop digital multimeter 14, and the desktop digital multimeter 14 is connected to the computer 15.

[0048] The wind tunnel can generate a wind speed of 3m / s and a temperature step of 10-20℃. The air flow temperature can be adjusted in the range of room temperature-500℃ according to the actual application environment, and the air flow rate can be adjusted in the range of 0-30m / s.

[0049] Example 2 Taking the airflow environment as an example, the above-mentioned device and method for measuring the dynamic response characteristic parameters of a temperature sensor are described in detail below. The measuring device includes a liquid fluid environment, a first displacement sensor 28, an electromagnetic ejection device and a control unit.

[0050] The difference between this embodiment 2 and embodiment 1 lies in the convection environment. The structures of the electromagnetic ejection device and the control unit are the same. The convection environment in this embodiment is a liquid fluid environment. The liquid fluid environment is described in detail below.

[0051] The liquid fluid environment includes a water tank 16 , a stirring device, a heater and a temperature controller 18 .

[0052] The water tank is fixed on a bracket 22 and a cover plate 26 is provided on the 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 the motor is connected to the 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 stirrer. A measuring hole is provided on the cover plate, and the temperature sensor to be measured extends into the fluid through the measuring hole. The first position sensor 28 is provided on the cover plate. A drain port is provided on the side wall of the water tank, and a water inlet is provided on the cover plate.

[0053] The cover can effectively eliminate the natural convection of hot air upward near the water tank, which causes the sensor to be tested to feel the temperature change in advance, thereby affecting the test data.

[0054] A Pitot tube 21 is provided in the water tank, and the Pitot tube 21 points to the axis of the cylindrical water tank 16. The Pitot tube 21 is connected to a Rosemount differential pressure transmitter 23, and the Rosemount differential pressure transmitter 23 is connected to a first DC power supply 24. The Pitot tube 21 is fixed to a bracket 22 and is located in the arc-shaped opening groove of the cover plate 26.

[0055] During the test, the temperature sensing end of the temperature sensor to be tested in the water tank 16 has the same coordinates as the leading edge of the Pitot tube in the radial and height directions.

[0056] The heater is arranged in the water tank for heating 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 socket of the thermostat 18.

[0057] The water flow environment can provide a flow rate of 0.4±0.05m / s. If the temperature sensor to be measured is a thermocouple, a temperature step of 40-50°C is used; if it is a thermal resistor, a temperature step of <10°C is used. The second DC power supply 25 supplies power to the motor 19 of the stirring rod 20, and the flow rate of water is controlled by adjusting the voltage of the second DC power supply 25. The water temperature can be adjusted in the range of 0-100°C according to the actual application environment, and the flow rate of water can be adjusted in the range of 0-2.2m / s.

[0058] The measurement methods of Examples 1 and 2 are described below.

[0059] Step 1: Before measuring, adjust the two test environments to the target parameters; For the low-speed airflow environment of Example 1, the frequency of the frequency converter 2 of the fan 3 is adjusted in the low-speed airflow environment so that the indication of the hot wire anemometer 6 is stabilized at 3m / s. The voltage regulator 5 of the electric 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, a constant temperature step value within the range of 10-20°C is generated.

[0060] For the low-speed water flow environment of Example 2, in the low-speed water flow environment, the voltage value of the second DC power supply 25 that powers the motor 19 of the stirring rod 20 is adjusted to be about 8.0V, so that the indication of the Rosemount differential pressure transmitter 23 is about 80Pa, that is, the water flow rate is 0.4m / s. If the thermocouple is tested, the target temperature of the thermostat 18 is set to be 40-50℃ higher than the ambient temperature; if the thermal resistor is tested, the target temperature of the thermostat 18 is set to be no more than 10℃ higher than the ambient temperature. When the high-power electric heating ring 8 heats the water quickly at the beginning and the temperature approaches the set temperature value, the high-power electric heating ring 8 is cut off, and the low-power electric heating rod 17 is used to heat the water temperature to the target temperature. During the test, when the water temperature is lower than the target temperature due to heat dissipation, the low-power electric heating rod 17 automatically heats up to control the water temperature to be constant.

[0061] The use of two sets of electric heating elements with different powers can not only shorten the heating time, but also eliminate the disadvantage of large thermal inertia of high-power heating devices, which is conducive to more accurately controlling the water temperature to stabilize at the target temperature.

[0062] 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 , and place the conductive slider 9 on the upper end of the vertical guide rail 11 .

[0063] Step 3, run the data acquisition program, and then close the switch 31 through the computer 15. The vertical guide rail 11 generates an alternating magnetic field, and current flows through the conductive slider 9. Under the action of the magnetic field, it is electromagnetically ejected along the vertical guide rail 11 into the environment to be tested. The temperature sensor 10 to be tested in the hole of the conductive slider 9 instantly falls into the target height of the environment to be tested. When the temperature sensor 10 to be tested falls into the appropriate height of the environment to be tested, both ends of the conductive slider 9 fall on the supporting platform 12.

[0064] Step 4: Obtain the initial moment when the temperature sensor 10 to be tested falls into the environment to be tested according to the first displacement sensor and the second displacement sensor respectively.

[0065] Observe the temperature information and the corresponding time recorded by the data acquisition card 13 on the computer 15, and obtain the time corresponding to the specified percentage of the ambient temperature step amount of the temperature sensing part of the temperature sensor 10 to be measured by linear interpolation according to the measured data, as the final time. According to the initial time and the final time, the dynamic response characteristic parameters of the temperature sensor 10 to be measured are calculated.

[0066] The temperature t corresponding to the time constant τc is given by =63.2% calculation, perform linear difference on the measured data, obtain the time corresponding to t, and the time interval between the time and the initial time is the time constant.

[0067] Example 3 Use a K-type exposed thermocouple for testing, with a temperature sensing point diameter of 0.7mm, and connect the thermocouple leads to H and L of channel 1 of the data acquisition card. Run the Labview acquisition and display program.

[0068] The room temperature is 22.0℃, a low-speed airflow environment is used, the temperature step is selected as 13.0℃, and the airflow is heated to 35.0℃. The acquisition frequency of the acquisition card is 14Hz, and the thermocouple is instantly placed in the test environment. The initial time is the 13th data point at 11:59:24, and the temperature of the thermocouple sensing point reaches 30.2℃, which is 63.2% of the excess temperature. The corresponding time is the 7th group of data points at 11:59:28. The calculated duration is 3.64s, that is, in a low-speed airflow and normal temperature environment, the time constant of the thermocouple is 3.64s.

[0069] In a low-speed water flow environment, the room temperature is 20.4°C, and the temperature step is 44°C, that is, the water is heated to 64.4°C. When the temperature of the thermocouple sensing point is 57.4°C, the measured time is 0.082s, that is, the time constant of the thermocouple in a low-speed water flow and normal temperature environment is 0.082s.

[0070] Example 4 Use a four-wire thermal resistor with a Pt100 calibration number for testing. The two red wires are connected to the H of the acquisition card channel 1 and channel 11, and the two white wires are connected to the L of the acquisition card channel 1 and channel 11. Run the Labview acquisition and display program.

[0071] When the frequency of inverter 2 of fan 3 is set to 24.2Hz, the indication of hot wire anemometer 6 is stable at 3m / s. The room temperature is 20.3℃, a low-speed airflow environment is used, and the selected temperature step is 11.0℃, that is, the airflow is heated to 31.3℃. The acquisition frequency of the acquisition card is 14Hz, and 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 group of data points at 9:57:49. The calculated duration is 44.71s, that is, in a low-speed airflow and normal temperature environment, the time constant of the Pt100 platinum resistor is 44.71s.

[0072] In a low-speed water flow environment, the room temperature is 18.6°C, the temperature step is 8.9°C, that is, the water is heated to 27.5°C, the thermal resistor temperature reaches 24.2°C, and the measured time is 3.71s, that is, the time constant of the Pt100 platinum resistor in a low-speed water flow and normal temperature environment is 3.71s.

[0073] The temperature sensor dynamic response characteristic parameter measurement device provided in the present application adopts the third type of boundary conditions as the test environment, and adopts air flow and water flow as two test environments. It is suitable for most temperature measurement scenarios in actual engineering, and the test results have a 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 is realized, which has practical value in engineering applications and is conducive to the selection of sensors in practical applications.

[0074] In addition, the measuring device can not only test the scenario where the actual test environment is convection, but also test the scenario where the actual test environment contains a large radiation heat transfer amount. The radiation heat transfer amount is converted into convection heat transfer amount, and the total heat transfer coefficient is obtained according to the converted convection heat transfer coefficient. Then, the appropriate medium and flow rate are selected to test the radiation superimposed convection environment.

[0075] Secondly, the measuring device and method can also be used in the teaching of "Heat Transfer". "Heat Transfer" is a core basic course for majors such as energy and power engineering, nuclear engineering, aircraft power engineering, process equipment and control engineering, architectural environment, and human settlement environment science and technology, and the heat conduction experiment is an important part of the "Heat Transfer" experiment. At present, the heat conduction experiments offered by domestic universities are mainly steady-state heat conduction, and there are relatively few unsteady-state heat conduction experiments. Occasionally, some universities offer experiments that use unsteady-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 value. It is necessary to study the unsteady-state process. Therefore, it is necessary and practical to carry out more abundant unsteady-state heat conduction experiments. 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 for a long time in class because they must reach a steady state before testing. They can be combined with unsteady-state heat conduction experiments for alternating tests, which can not only improve the knowledge points, but also improve the utilization rate of class time. This measuring device well reflects the basic theory of non-steady-state heat conduction in heat transfer, and applies a simplified method for analyzing simple non-steady-state heat conduction problems - the lumped parameter method. It creatively expands the non-steady-state heat conduction experiment and can be combined with the steady-state heat conduction experiment for alternating tests. It can not only improve the knowledge system of the experimental teaching link of "Heat Transfer", but also effectively improve the utilization of classroom time.

[0076] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A device for measuring dynamic response characteristic parameters of a temperature sensor, characterized in that: It includes a convection environment and a control unit, and a displacement sensor and an electromagnetic ejection device connected to the control unit; The electromagnetic ejection device 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, and the conductive slider can move toward the measuring hole of the convection environment under the action of the electromagnetic force; The displacement sensor is arranged at the edge of the measuring hole of the convection environment, and is used to obtain the moment 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 to the control unit; An environment control device is provided in the convection environment for adjusting and controlling the environmental parameters of the convection environment.

2. A temperature sensor dynamic response characteristic parameter measuring device according to claim 1, characterized in that: The guide rail is vertically arranged on the support platform, the conductive slider is connected to the slide groove of the guide rail, and a fixing hole for fixing the temperature sensor to be measured is arranged at the center of the conductive slider; The vertical guide rail, the conductive slider, the high-frequency AC power supply and the switch are connected in series, and the switch is connected to the control unit.

3. A temperature sensor dynamic response characteristic parameter measuring device according to claim 1 or 2, characterized in that: The convection environment is an air flow environment and a liquid flow environment.

4. A temperature sensor dynamic response characteristic parameter measuring device according to claim 3, characterized in that: The airflow environment includes a wind tunnel, and the environment control device corresponding to the airflow environment includes a fan, a heat source and a temperature control device; The fan is connected to the wind tunnel to form airflow inside the wind tunnel. The heat source is arranged in the airflow circulation channel. The heat source is used to heat the airflow in the wind tunnel. The heat source is connected to 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.

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

6. The device for measuring the dynamic response characteristic parameters of a temperature sensor according to claim 3, characterized in that: The liquid flow environment includes a water tank, and the environment control device corresponding to the liquid flow includes 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 to the heater; A cover plate is arranged on the top of the water tank, a measuring hole is arranged on the cover plate, and a displacement sensor is arranged on the cover plate and located at the edge of the measuring hole.

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

8. A temperature sensor dynamic response characteristic parameter measuring device according to any one of claims 1, 4-7, characterized in that: The mouth of the measuring hole is provided with a heat shield, and a one-way valve is provided in the heat shield.

9. A temperature sensor dynamic response characteristic parameter measuring device according to claim 8, characterized in that: The heat shield is a nozzle that converges from bottom to top; The one-way valve includes a fixed ring, which is arranged in the tapered nozzle. A plurality of flexible diaphragms are arranged at the lower end of the fixed ring. The upper end of the diaphragm is connected to the lower edge of the fixed ring. The lower end of the diaphragm is inclined toward the axial direction of the fixed ring, and the lower ends of the plurality of diaphragms abut against each other.

10. A method for measuring a temperature sensor dynamic response characteristic parameter measuring device according to any one of claims 1 to 9, characterized in that: include: The control unit obtains the time when the temperature of the temperature sensing end of the temperature sensor reaches the percentage of the ambient temperature step amount set and takes it as the final moment, and takes the moment when the temperature sensing end of the temperature sensor enters the convection environment as the initial moment, and determines the dynamic response characteristic parameters of the temperature sensor to be measured based on the initial moment and the final moment.

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