An experimental device and method for measuring the stefan-boltzmann constant

Abstract

The application discloses an experimental device and method for measuring Stefan-Boltzmann constant, and relates to the technical field of thermal radiation measurement. The device comprises a thermal radiation experiment box, a data acquisition and processing box, a program processor and a constant current and voltage power supply. The thermal radiation experiment box is composed of a black cylinder, a smooth cylinder, a base, a support, a heating column, a wire groove, a base and a shell. The data acquisition and processing box is composed of an automatic control heating circuit, a two-way temperature signal acquisition circuit, a voltage reduction and power supply circuit, a single-chip microcomputer and a liquid crystal display. The single-chip microcomputer is used to calculate the experimental value of the Stefan-Boltzmann constant. Finally, the program processor is used for visual data analysis. The application can effectively reduce the system error caused by non-thermal radiation, ensure the accuracy of the measurement of the Stefan-Boltzmann constant, and can be used as a thermal radiation experiment project in a physical experiment course, so that students can better understand the Stefan-Boltzmann law in blackbody radiation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal radiation measurement, in particular to an experimental device and method for measuring Stefan-Boltzmann constant. BACKGROUND

[0002] A black body is an idealized object that absorbs all incident electromagnetic radiation, reflecting or transmitting none of it. If an object can completely reflect the radiation projected on it, such object is called a white body, also called a full reflector. Stefan-Boltzmann law states that the total energy radiated per unit surface area of a black body across all wavelengths per unit time (power emitted) is directly proportional to the fourth power of the black body's temperature in Kelvin. Stefan-Boltzmann law was first derived by Stefan in 1879 by inductive summary of experimental data, and then Boltzmann derived the same conclusion as Stefan's inductive summary in 1884 according to thermodynamic theory. Stefan-Boltzmann law provides a basis for the calculation of thermal radiation, and the surface temperature of an object can be determined by measuring its radiant exitance, which has a wide application in thermodynamics and thermal radiation research.

[0003] The basic modes of heat transfer include heat convection, heat conduction and heat radiation. Among them, heat convection follows Newton's cooling law, heat conduction follows Fourier's law, and heat radiation of a black body follows Stefan-Boltzmann law. In the physical experiment course, there are few experimental projects related to the quantitative relationship of thermal radiation, so it is necessary to develop a thermal radiation measurement experimental device to help students better understand and master the thermal radiation rules and theoretical knowledge. In the black body radiation measurement experiment, since there is no ideal black body, there will inevitably be heat loss in the form of non-thermal radiation, which brings measurement error to the traditional black body radiation experiment. Currently, the Stefan-Boltzmann constant in Stefan-Boltzmann law is mainly obtained by theoretical derivation, rather than experimental measurement, and the value is often given as a known quantity.

[0004] Therefore, it is of great practical significance for students to understand the black body radiation rules to develop a black body radiation experimental device that can effectively reduce the systematic error caused by non-thermal radiation in the experiment and calculate the experimental value of Stefan-Boltzmann constant. SUMMARY

[0005] The present application aims to solve the above problems, and provides an experimental device and method for measuring Stefan-Boltzmann constant, which is simple, easy to operate, stable, low in cost, high in precision, easy to miniaturize, and can be used as a thermal radiation experimental project in the physical experiment course, so that students can better understand the black body radiation experimental rules and deepen their understanding of Stefan-Boltzmann law.

[0006] In order to achieve the above purpose, the scheme of the present application is as follows:

[0007] This invention provides an experimental apparatus for measuring the Stefan-Boltzmann constant. The apparatus includes a thermal radiation experimental chamber, a data acquisition and processing chamber, a program processor, and a constant current and voltage regulated power supply, connected sequentially. The thermal radiation experimental chamber includes a base and a black cylinder (serving as a blackbody) and a smooth cylinder (serving as a total reflector) axially mounted on the base. Both the black cylinder and the smooth cylinder have open ends away from the base, and resistance temperature sensors are mounted on their sides. A support is also mounted on the base, and a heating column is detachably mounted on the support. The heating column is used to heat the black cylinder and the smooth cylinder during the experiment. The data acquisition and processing chamber includes a housing and a cover mounted on the housing. The housing integrates an automatic heating control circuit, a two-channel temperature signal acquisition circuit, a step-down and power supply circuit, and a microcontroller. An LCD screen is mounted on the cover. The heating control circuit controls the heating column to generate heat, thereby raising the temperature of the black cylinder and the smooth cylinder to the target temperature. The two-channel temperature signal acquisition circuit collects the resistance change of the resistive temperature sensor to calculate the current temperature. The step-down and power supply circuit steps down and regulates the constant current regulated power supply and supplies power to all circuits. The microcontroller is also connected to a program processor. The microcontroller processes the data collected by the automatic heating control circuit, the two-channel temperature signal acquisition circuit, and the step-down and power supply circuit to calculate the experimental value of the Stefan-Boltzmann constant. Then, it displays the measurement data on the LCD screen and transmits the data to the program processor in real time. The program processor performs visual analysis of the real-time measured data. The LCD screen displays measurement data including ambient temperature, target temperature, cylinder temperature, and heating power, as well as the experimental value of the Stefan-Boltzmann constant.

[0008] Furthermore, the thermal radiation experimental chamber also includes a base mounted on the pedestal, the base being made of a high-temperature resistant material; grooves are provided on both sides of the base, the grooves being used to respectively hold the black cylinder and the smooth cylinder; the support is also mounted on the pedestal.

[0009] Furthermore, the black cylinder and the smooth cylinder are identical in shape and size and are both made of metal; the inner and outer surfaces of the black cylinder are coated with a material with high thermal radiation absorption rate to ensure high thermal radiation absorption rate; the inner and outer surfaces of the smooth cylinder are polished to ensure high thermal radiation reflectivity.

[0010] Furthermore, the heating column includes a winding post and a heating wire evenly wound on the surface of the winding post; the outer diameter of the winding post is smaller than the inner diameter of the black cylinder and the smooth cylinder, and its height is the same as the height of the black cylinder and the smooth cylinder; a partition is connected to the end of the heating column away from the base, and the diameter of the partition is larger than the outer diameter of the black cylinder and the smooth cylinder; two terminals and a handle are also provided on the side of the partition away from the base, and the two ends of the heating wire are respectively connected to the two terminals, which are connected to the automatic control heating circuit; the winding post is made of a high-temperature resistant material, and the partition is made of a high-temperature resistant and non-conductive material.

[0011] Furthermore, the base is also provided with a wire groove, through which the wire of the resistive temperature sensor passes and is connected to the two temperature signal acquisition circuits.

[0012] Furthermore, the automatic heating control circuit includes an N-channel MOSFET and a gate drive circuit. The N-channel MOSFET is used to change the current flowing through the heating wire by changing the gate voltage, thereby changing the heating power of the heating wire. The gate drive circuit includes a gate drive chip, a current detection chip, and dual operational amplifiers. The gate drive chip integrates a logic signal input processing circuit, a dead-time control circuit, a latching circuit, a level shifting circuit, a pulse filtering circuit, and an output drive circuit, used to amplify the input signal or control signal to a level suitable for driving the N-channel MOSFET. The current detection chip detects the current flowing through the heating wire through the Hall effect, converts the current signal into a voltage signal, and then scales the voltage signal through the dual operational amplifier and a resistor divider circuit to provide an analog voltage signal to the microcontroller. The analog voltage signal output by the microcontroller is amplified by the gate drive chip to adjust the gate voltage, thereby controlling the conduction and cutoff of the N-channel MOSFET.

[0013] Furthermore, the two-channel temperature signal acquisition circuit employs a high-multiplier differential voltage amplifier circuit and a Wheatstone bridge circuit composed of dual operational amplifiers and precision resistors to acquire the resistance changes of the resistive temperature sensors, thereby calculating the current temperature. The two-channel temperature signal acquisition circuit also includes a signal relay, which controls the contact state of the signal relay by providing a signal at the control voltage input terminal, thereby enabling the switching of temperature detection between the two resistive temperature sensors in the circuit.

[0014] Furthermore, the step-down and power supply circuit includes a step-down integrated voltage regulator chip and a power supply circuit. The step-down integrated voltage regulator chip is used to step down and regulate the constant current regulated power supply voltage. The power supply circuit includes a digital power supply circuit and an analog power supply circuit. The digital power supply circuit includes a low-dropout linear regulator chip, which performs a two-stage step-down to obtain a digital level. The digital level is used to provide a stable power supply voltage for the microcontroller to ensure its normal operation. The analog power supply circuit includes a reference voltage chip, which delivers a stable analog reference power supply to provide a reference voltage for the microcontroller, ensuring that the microcontroller can accurately compare, convert, and measure analog signals.

[0015] The present invention also provides an experimental method for measuring the Stefan-Boltzmann constant, wherein the experimental method uses the experimental apparatus for measuring the Stefan-Boltzmann constant as described above; the experimental method includes:

[0016] (1) Measure the outer diameter D and height H of the smooth cylinder and the black cylinder, and calculate the surface area S of the smooth cylinder and the black cylinder: S = π·D·H;

[0017] (2) Turn on the constant current regulated power supply, read the ambient temperature on the LCD screen, remove the heating column located on the bracket, and put it into the smooth cylinder;

[0018] (3) After setting the target temperature, start heating. Once the temperature of the smooth cylinder stabilizes, record the heating power of the heating wire inside the smooth cylinder.

[0019] (4) Take the heating column out of the smooth cylinder and put it into the black cylinder. Set the same target temperature as in step (3) and repeat the operation of step (3). Record the heating power of the heating wire in the black cylinder.

[0020] (5) Place the heating column back into the smooth cylinder, input different target temperatures, and repeat steps (3) and (4). Record the experimental data and perform visualization analysis through the program processor.

[0021] (6) The formula for calculating the Stefan-Boltzmann constant σ is:

[0022]

[0023] Where T1 is the ambient temperature, T2 is the target temperature, P1 is the heating power of the heating wire inside the smooth cylinder, and P2 is the heating power of the heating wire inside the black cylinder.

[0024] This invention provides an experimental apparatus and method for measuring the Stefan-Boltzmann constant. Compared with existing technologies, its advantages are: effectively reducing the systematic error caused by the non-thermal radiation energy loss of the black cylinder, thereby accurately determining the Stefan-Boltzmann constant and verifying the Stefan-Boltzmann law; using a microcontroller to control the data acquisition circuit and transmitting experimental data to the program processor in real time, which improves the efficiency of experimental measurement and data processing. This invention has a clear physical principle, is simple to operate, low in cost, highly stable, highly accurate, has a short response time, is easy to miniaturize, and achieves intelligent temperature control and data visualization, with a more user-friendly interface, effectively improving experimental efficiency. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a structural diagram of an experimental apparatus and method for measuring the Stefan-Boltzmann constant according to the present invention.

[0027] Figure 2 This is a structural block diagram of the data acquisition and processing box of the present invention.

[0028] In the diagram: 1-Thermal radiation experimental chamber; 2-Data acquisition and processing box; 3-Program processor; 4-Constant current and voltage regulated power supply; 11-Black cylinder; 12-Smooth cylinder; 13-Base; 14-Support; 15-Heating column; 16-Wire groove; 17-Base; 18-Outer shell of thermal radiation experimental chamber; 21-Automatic control heating circuit; 22-Dual temperature signal acquisition circuit; 23-Step-down and power supply circuit; 24-Microcontroller; 25-LCD display screen; 26-Outer shell of data acquisition and processing box; 151-Winding post; 152-Heating wire; 153-Partition; 154-Terminal; 155-Handle; 141-Rectangular wooden board; 142-Square wooden board with openings; 221-Resistive temperature sensor; 261-Lid; 262-Box body. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0030] Example 1:

[0031] like Figure 1 and Figure 2The diagram illustrates the structure of an experimental apparatus and method for measuring the Stefan-Boltzmann constant according to the present invention. The experimental apparatus in this embodiment includes a thermal radiation experimental chamber 1, a data acquisition and processing box 2, a program processor 3, and a constant current and voltage regulated power supply 4. The thermal radiation experimental chamber 1 further includes a black cylinder 11, a smooth cylinder 12, a base 13, a support 14, a heating column 15, a wire groove 16, a base 17, and a thermal radiation experimental chamber shell 18. The black cylinder 11 and the smooth cylinder 12 are respectively considered as a "black body" and a "total reflector." The data acquisition and processing box 2 further includes an automatic heating control circuit 21, a two-channel temperature signal acquisition circuit 22, a step-down and power supply circuit 23, a microcontroller 24, an LCD screen 25, and a data acquisition and processing box shell 26. The experimental method of this embodiment includes obtaining the ambient temperature, placing the heating column 15 into the smooth cylinder 12 and the black cylinder 11 respectively and setting the same target temperature, waiting for the cylinder temperature to reach equilibrium, obtaining the heating power of the heating wires in the smooth cylinder 12 and the black cylinder 11, calculating the experimental value of the Stefan-Boltzmann constant through the STM32 microcontroller 24, and finally performing visualization data analysis through the program processor 3.

[0032] In this embodiment, the heating column 15 is composed of a winding column 151 and a heating wire 152. The winding column 151 and the base 13 are made of polytetrafluoroethylene (PTFE), which is a translucent white waxy material with characteristics such as high temperature resistance, corrosion resistance, and high stability, and can withstand the high temperature caused by the experiment.

[0033] The winding post 151 is a hollow cylindrical structure with an inner diameter of 5.00 cm and an outer diameter of 6.50 cm. The outer diameter of the winding post 151 is smaller than the inner diameter of the black cylinder 11 and the smooth cylinder 12. The height of the winding post 151 is the same as the height of the black cylinder 11 and the smooth cylinder 12, which is 12.00 cm.

[0034] The surface of the winding post 151 is wound with evenly distributed heating wires 152 made of iron-chromium-aluminum to provide a heat source for the experiment.

[0035] The heating column 15 is fixed on a partition 153. The partition 153 has a diameter of 9.00cm and a thickness of 2.0mm. The partition 153 is made of high-temperature resistant and non-conductive bakelite material. On the other side of the partition 153, there are two terminal blocks 154 and a handle 155.

[0036] The two ends of the heating wire 152 are connected to the two terminals 154 of the partition 153, and these two terminals 154 are connected to the automatic control heating circuit 21.

[0037] Black cylinder 11 and smooth cylinder 12 are symmetrically located on the left and right sides of base 13. Base 13 is a rectangular thin plate measuring 36.00cm × 13.00cm × 2.00cm. Base 13 is fixed to a rectangular base 17 measuring 37.00cm × 26.00cm × 1.00cm. Eight extra-thick soft rubber feet are located under base 17. Both black cylinder 11 and smooth cylinder 12 are made of aluminum and have the same shape and size. The difference lies in that the inner and outer surfaces of black cylinder 11 are coated with high-temperature resistant black paint, while the inner and outer surfaces of smooth cylinder 12 are polished. Black cylinder 11 has a high thermal radiation absorption rate, while smooth cylinder 12 has a high thermal radiation reflectivity. Both black cylinder 11 and smooth cylinder 12 are hollow structures without top or bottom surfaces. In this embodiment, the inner diameter of black cylinder 11 and smooth cylinder 12 is 7.00cm, the height is 12.00cm, and the aluminum cylinder wall thickness is 1.0mm.

[0038] Before any experimental measurements were performed, the heating column 15 was placed on the support 14 (19.50 cm high). The support 14 was made of hardwood. A rectangular wooden board 141 (6.00 cm × 2.00 cm × 18.50 cm) served as the column support structure. A square wooden board 142 with a side length of 12.00 cm and a thickness of 6.0 mm with an opening was fixed on top of the rectangular wooden board 141. The two were fixed at one side of the square wooden board 142, and the other side opposite to this side was the opening. This opening was arch-shaped to facilitate the placement of the heating column 15 on the support 14. The support 14 was fixed on the base 17.

[0039] In this embodiment, PT100 temperature sensors 221 made of platinum resistance thermometers are installed on the sides of both the black cylinder 11 and the smooth cylinder 12. The wires of the PT100 temperature sensors 221 pass through the wire groove 16 fixed on the base 13 and are connected to the two temperature signal acquisition circuits 22 of the data acquisition and processing box 2. The wire groove 16 selected in this embodiment is made of PVC material.

[0040] In this embodiment, the outer shell 18 of the thermal radiation experimental chamber is rectangular (37.00cm × 26.00cm × 23.00cm). Its length and width are larger than the base 13, and its height is greater than the support 14. The outer shell 18 can be fastened to the thermal radiation device, providing mechanical protection and waterproof and dustproof protection. The outer shell 18 of the thermal radiation experimental chamber in this embodiment is made of acrylic material.

[0041] In this embodiment, the STM32 microcontroller 24 processes the data collected by the automatic heating control circuit 21, the two-channel temperature signal acquisition circuit 22, and the step-down and power supply circuit 23, and calculates the experimental value of the Stefan-Boltzmann constant. Then, it displays the measurement data on the LCD screen 25 and transmits the data to the program processor 3 in real time. The LCD screen 25 (7.00cm × 10.00cm) displays the measurement data, including ambient temperature, target temperature, temperature and heating power P1 of the smooth cylinder 12, temperature and heating power P2 of the black cylinder 11, and the experimental value of the Stefan-Boltzmann constant. The unit of temperature is °C, the unit of current is A, the unit of power is W, and the unit of the Stefan-Boltzmann constant is W·m³. -2 ·K -4 .

[0042] Wherein, heating power P = I 2 ·R, the current I is measured by the current detection chip in the automatic control heating circuit 21, and R is the resistance of the heating wire 152.

[0043] Below the LCD screen 25 are four buttons, numbered 1, 2, 3, and 4. These buttons are used to set and switch the display content on the LCD screen 25, including setting the temperature mode, increasing or decreasing the temperature, and switching the connection of the STM32 microcontroller 24 to the PT100 temperature sensor 221 on the side of the black cylinder 11 or the smooth cylinder 12. The LCD screen 25 and the four buttons are mounted on the cover 261 of the data acquisition and processing box housing 26. Except for the program processor 3, all the circuit components in the data acquisition and processing box 2 are housed inside the housing 261 of the housing 26.

[0044] The data acquisition and processing box shell 26 selected in this embodiment has a rectangular structure (19.50cm×14.50cm×10.00cm), including a cover 261 (19.50cm×14.50cm×2.00cm) and a box body 262 (19.50cm×14.50cm×8.00cm). There are screws on the four corners of the cover 261, which can be easily opened to repair the circuit components inside the data acquisition and processing box 2. The data acquisition and processing box shell 26 provides mechanical protection, waterproof and dustproof protection.

[0045] In this embodiment, the automatic control heating circuit 21 uses an N-channel MOS transistor and a gate drive circuit to control the current passing through the heating wire 152 and the heating power of the heating wire 152.

[0046] The gate drive circuit includes an EG3014 gate drive chip, an ACS712-20A current sensing chip, and an LM358 dual operational amplifier. The EG3014 gate drive chip integrates logic signal input processing circuitry, dead-time control circuitry, latch-up circuitry, level shifting circuitry, pulse filtering circuitry, and output drive circuitry, used to amplify the input signal or control signal to a level suitable for driving the N-channel MOSFET. The ACS712-20A current sensing chip detects the current flowing through the heating wire 152 using the Hall effect, converting the current signal into a voltage signal. This voltage signal is then scaled by a 5:3.3 ratio using the LM358 dual operational amplifier and a resistor divider circuit, providing an analog voltage signal of 0–3.3V to the STM32 microcontroller 24. The analog voltage signal output by the STM32 microcontroller 24, amplified by the EG3014 gate drive chip, can adjust the gate voltage, thereby controlling the conduction and cutoff of the N-channel MOSFET.

[0047] In this embodiment, the two-channel temperature signal acquisition circuit 22 uses an LM358 dual operational amplifier and a precision resistor to form a 100-fold differential voltage amplifier circuit and a Wheatstone bridge circuit to collect the resistance changes of the PT100 temperature sensor 221 on the sides of the black cylinder 11 and the smooth cylinder 12, thereby calculating the current temperature.

[0048] The dual-channel temperature signal acquisition circuit 22 also includes a G6K-2F-Y-5V signal relay. By providing a signal to the control voltage input terminal of the G6K-2F-Y-5V signal relay, the contact state of the G6K-2F-Y-5V signal relay is controlled, thereby realizing the switching of temperature detection of the two PT100 temperature sensors 221 in the circuit.

[0049] In this embodiment, the step-down and power supply circuit 23 includes an LM2596 step-down integrated voltage regulator chip and a power supply circuit. The LM2596 step-down integrated voltage regulator chip steps down and regulates the constant current regulated power supply voltage (24VDC) to 5VDC. The power supply circuit includes a 3.3V digital power supply circuit and a 3.3V analog power supply circuit. The 3.3V digital power supply circuit includes an AMS1117-3.3 low dropout linear regulator chip, which performs a two-stage step-down to obtain a 3.3V digital level. This digital level is used to provide a stable power supply voltage for the STM32 microcontroller 24 to ensure its normal operation. The 3.3V analog power supply circuit includes a REF196 reference voltage chip, which provides a stable analog reference power supply to the STM32 microcontroller 24, ensuring that the STM32 microcontroller 24 can accurately compare, convert, and measure analog signals.

[0050] In this embodiment, the STM32 microcontroller 24 supports USB interface download and features low power consumption, high performance, and multiple communication interfaces. The communication interfaces of the STM32 microcontroller 24 are connected to the input terminals of the automatic heating control circuit 21, the input terminals of the two-channel temperature signal acquisition circuit 22, and the buttons below the LCD screen 25. The communication interfaces of the STM32 microcontroller 24 are also connected to the busbar in the circuit, thereby connecting to the LCD screen 25.

[0051] In this embodiment, the constant current regulated power supply 4 adopts the ATTENAPS3005Dm DC regulated power supply, which has a 4-digit ampere display, a rated voltage output range of 0-30V, and a rated current output range of 0-5A. This instrument has high accuracy, and the output voltage and current are continuously adjustable within the rated range. It has multiple protection functions such as current limiting and voltage reduction, short circuit protection, and over-temperature protection.

[0052] In one specific embodiment, four buttons are provided below the LCD screen 25. Their functions are as follows: button 1 is the heating button; button 2 is for adjusting the temperature (after button 2 is activated, button 1 decreases the temperature, button 3 increases the temperature, and button 4 switches the digital position); button 3 is for adjusting the opening degree (button 1 decreases, button 2 increases); and button 4 is for switching the PT100 temperature sensor 221. Exiting the debugging mode means exiting the debugging of the N-channel MOSFET in the automatic heating control circuit 21. Adjusting the opening degree involves debugging the N-channel MOSFET to control the current passing through the heating wire 152, thereby controlling the power of the heating wire 152.

[0053] The experimental method for this experimental setup is as follows:

[0054] (1) Measure the outer diameter D and height H of the smooth cylinder 12, and calculate the surface area S of the smooth cylinder 12 as S = π·D·H; since the black cylinder 11 and the smooth cylinder 12 have the same dimensions, it is not necessary to measure the dimensions of the black cylinder 11. Figure 1 Connect the experimental setup.

[0055] (2) Turn on the constant current and voltage power supply 4, preheat for 10 minutes, read the ambient temperature T1 on the LCD screen 25, remove the heating column 15 located on the bracket 14, and put it into the smooth cylinder 12.

[0056] (3) Set the target temperature T2 by pressing button 2 (press button 2 to enter the temperature setting mode, press button 1 to increase the temperature, press button 3 to decrease the temperature, press button 2 after confirming the temperature, and the setting is complete), then press button 1 to start heating. When the temperature reaches near the target temperature T2, it will automatically enter the debugging mode to start intelligent adjustment. By observing the LCD screen 25, wait for the temperature of the smooth cylinder 12 to stabilize, and record the heating power P1 of the heating wire inside the smooth cylinder 12.

[0057] (4) Press button 3 to exit the debugging mode. Press button 4, the STM32 microcontroller 24 connects to the PT100 temperature sensor 221 on the side of the black cylinder 11, removes the heating column 15 from the smooth cylinder 12 and puts it into the black cylinder 11, sets the target temperature T2 to the same as in step (3) by pressing the button and repeats the operation of step (3), observes the reading on the LCD screen 25, and records the heating power P2 of the heating wire in the black cylinder 11.

[0058] (5) Place the heating column 15 back into the smooth cylinder 12, input different target temperatures T2, and repeat steps (3) and (4). Record the experimental data and perform visualization analysis through the program processor 3.

[0059] (6) The formula for calculating the Stefan-Boltzmann constant σ is:

[0060]

[0061] Where T1 is the ambient temperature, T2 is the target temperature, P1 is the heating power of the heating wire 152 inside the smooth cylinder 12, and P2 is the heating power of the heating wire 152 inside the black cylinder 11.

[0062] While a particular embodiment of the invention has been shown and described in detail, those skilled in the art will understand that the above embodiments may be modified without departing from the scope of the invention. Therefore, the structures contained in the foregoing description and shown in the accompanying drawings should be considered exemplary and not intended to limit the scope of the patent application of this invention.

Claims

1. An experimental apparatus for measuring the Stefan-Boltzmann constant, characterized in that, The device comprises a heat radiation experiment box, a data acquisition and processing box, a program processor and a constant current stabilized power supply connected in sequence. The heat radiation experiment box comprises a base, a black cylinder serving as a black body and a smooth cylinder serving as a total reflector arranged on the base in an axial direction, the black cylinder and the smooth cylinder are both open at an end face away from the base and are both provided with an electric resistance temperature sensor on a side face, the base is further provided with a support, and the support is detachably provided with a heating column for being respectively placed in the black cylinder and the smooth cylinder to heat the black cylinder and the smooth cylinder during an experiment. The data acquisition and processing box comprises a box body and a cover arranged on the box body, the box body is integrated with an automatic control heating circuit, two temperature signal acquisition circuits, a voltage reduction and power supply circuit and a single-chip microcomputer, and the cover is provided with a liquid crystal display screen. The automatic control heating circuit is used for controlling the heating column to heat and then heat the black cylinder and the smooth cylinder to a target temperature, the two temperature signal acquisition circuits are used for collecting resistance changes of the electric resistance temperature sensors to calculate current temperatures, the voltage reduction and power supply circuit is used for voltage reduction and stabilization of the constant current stabilized power supply and power supply for all circuits, the single-chip microcomputer is further connected with a program processor, the single-chip microcomputer is used for processing and calculating an experimental value of the Stefan-Boltzmann constant according to data collected by the automatic control heating circuit, the two temperature signal acquisition circuits and the voltage reduction and power supply circuit, then displaying measurement data on the liquid crystal display screen and transmitting the data to the program processor in real time, the program processor is used for visual analysis of real-time measurement data, and the liquid crystal display screen is used for displaying measurement data including environmental temperature, target temperature, cylinder temperature and heating power and the experimental value of the Stefan-Boltzmann constant.

2. The experimental setup for measuring the Stefan-Boltzmann constant according to claim 1, characterized in that, The heat radiation experiment box further comprises a base arranged on the base, and the base is made of a high-temperature-resistant material, both sides of the base are respectively provided with a groove for respectively clamping the black cylinder and the smooth cylinder, and the base is further provided with the support.

3. The experimental setup for measuring the Stefan-Boltzmann constant according to claim 1, characterized in that, The black cylinder and the smooth cylinder are both metal and have the same shape and size, the inner surface and the outer surface of the black cylinder are both sprayed with a material with high heat radiation absorption rate to make the black cylinder have high heat radiation absorption rate, and the inner surface and the outer surface of the smooth cylinder are both polished to make the smooth cylinder have high heat radiation reflectivity.

4. The experimental setup for measuring the Stefan-Boltzmann constant according to claim 3, characterized in that, The heating column comprises a winding column and electric heating wires uniformly wound on the surface of the winding column, the outer diameter of the winding column is smaller than the inner diameters of the black cylinder and the smooth cylinder, and the height of the winding column is the same as the heights of the black cylinder and the smooth cylinder. An end of the heating column away from the base is connected with a partition plate, the diameter of the partition plate is greater than the outer diameters of the black cylinder and the smooth cylinder, two terminal posts and a handle are further arranged on a side of the partition plate away from the base, both ends of the electric heating wires are respectively connected to the two terminal posts, and the terminal posts are connected with the automatic control heating circuit. The winding post is made of high-temperature resistant material, and the partition is made of high-temperature resistant and non-conductive material.

5. The experimental setup for measuring the Stefan-Boltzmann constant according to claim 2, wherein, The base is further provided with a wire groove, and the wires of the resistance temperature sensor pass through the wire groove and are connected to the two-way temperature signal acquisition circuit.

6. The experimental setup for measuring the Stefan-Boltzmann constant according to claim 4, characterized in that, The automatic control heating circuit comprises an N-channel MOS tube and a gate drive circuit; The N-channel MOS tube is used for changing the heating power of the electric heating wire by changing the gate voltage to change the current through the electric heating wire; The gate drive circuit comprises a gate drive chip, a current detection chip and a double operational amplifier; the gate drive chip internally integrates a logic signal input processing circuit, a dead zone control circuit, a latching circuit, a level shifting circuit, a pulse filter circuit and an output drive circuit, which are used for amplifying the input signal or control signal to a level suitable for driving the N-channel MOS tube; the current detection chip detects the current flowing through the electric heating wire through the Hall effect, converts the current signal into a voltage signal, and the voltage signal is scaled by the double operational amplifier and the resistance dividing circuit, so as to provide an analog voltage signal for the single-chip microcomputer; the analog voltage signal output by the single-chip microcomputer is amplified by the gate drive chip, so as to adjust the gate voltage and control the conduction and cut-off of the N-channel MOS tube.

7. The experimental setup for measuring the Stefan-Boltzmann constant according to claim 1, wherein, The two-way temperature signal acquisition circuit comprises a double operational amplifier and a precision resistor to form a high-multiple voltage difference amplification circuit and a Wheatstone bridge circuit, which are used for collecting the resistance change of the resistance temperature sensor, so as to calculate the current temperature. The two-way temperature signal acquisition circuit further comprises a signal relay, and the contact state of the signal relay is controlled by providing a signal at the control voltage input end of the signal relay, so as to realize the temperature detection switching of the two resistance temperature sensors in the circuit.

8. The experimental setup for measuring the Stefan-Boltzmann constant according to claim 1, characterized in that, The voltage reduction and power supply circuit comprises a voltage reduction integrated voltage stabilizing chip and a power supply circuit; the voltage reduction integrated voltage stabilizing chip is used for voltage reduction and stabilization of the constant current stabilized power supply; the power supply circuit comprises a digital power supply circuit and an analog power supply circuit; The digital power supply circuit comprises a low-dropout linear voltage stabilizing chip, and a digital level is obtained by two-stage voltage reduction through the low-dropout linear voltage stabilizing chip; the digital level is used for providing a stable power voltage for the single-chip microcomputer, so as to ensure the normal work of the single-chip microcomputer; The analog power supply circuit comprises a reference voltage chip, which is used for delivering a stable analog reference power to provide a reference voltage for the single-chip microcomputer, so as to ensure that the single-chip microcomputer can accurately compare, convert and measure the analog signal.

9. An experimental method of measuring the Stefan-Boltzmann constant, characterized in that, The experimental method applies the experimental device for measuring the Stefan-Boltzmann constant according to any one of claims 1 to 8; the experimental method comprises: (1) Measure the outer diameter of the smooth cylinder and the black cylinder D , height H , obtain the surface area of the smooth cylinder and the black cylinder by calculation S = π · D · H ; (2) Turn on the constant current stabilized power supply, read the ambient temperature on the liquid crystal display, remove the heating column on the support, and put it into the smooth cylinder; (3) Set the target temperature and start heating, and record the heating power of the electric heating wire in the smooth cylinder after the temperature of the smooth cylinder is stable. (4) The heating column is taken out from the smooth cylinder and put into the black cylinder, the same target temperature as step (3) is set and the operation of step (3) is repeated, and the heating power of the heating wire in the black cylinder is recorded; (5) The heating column is put into the smooth cylinder again, different target temperatures are input, and steps (3) and (4) are repeated, experimental data are recorded and visualized analysis is carried out by a program processor; (6) the Stefan-Boltzmann constant σ The formula for calculating this is: wherein, T 1 is ambient temperature, T 2 is target temperature, P 1 is heating power of the electric heating wire in the smooth cylinder, P 2 is heating power of the electric heating wire in the black cylinder.

Images