A two-color infrared temperature calibration method for space station containerless material experiments

Abstract

The present application relates to a kind of two-color infrared temperature calibration methods for space station containerless material experiment, obtain the temperature variation of space station containerless material experiment.Heating temperature-time curve of sample measured under the preset certain two-color infrared slope, then mark the characteristic temperature on temperature-time curve, according to the single-color radiant intensity ratio invariable relationship, two-color infrared slope, characteristic temperature and the phase transition temperature obtained by phase diagram or thermal analysis experiment are substituted into the established equation relationship.The correction value of two-color infrared slope is solved, the correction value is substituted back into the equation relationship, and all the temperature data obtained are substituted into one by one, and the corresponding calibration temperature is solved.So far, the corrected two-color infrared slope and the calibrated temperature-time curve are obtained.The method proposed in the present application does not need to rely on thermocouple, and does not need to construct model in advance under the same environment and fit parameters, and the calibrated two-color infrared temperature can be controlled within a smaller error range at the characteristic temperature.

Description

Technical Field

[0001] This invention belongs to the field of containerless material experiments for space stations, and relates to a two-color infrared temperature calibration method for containerless material experiments for space stations. Background Technology

[0002] There are generally two methods for measuring the temperature of high-temperature objects: thermocouple measurement and infrared thermometry. The former is based on the thermoelectric effect, where changes in temperature cause changes in electrical potential; the latter is based on Planck's law of radiation, which states that any object not at absolute zero radiates energy, most of which is concentrated in the infrared region, and its radiation characteristics are related to both wavelength and temperature. Based on this, the temperature of the object can be determined. The dual-color infrared thermometry method determines temperature by the ratio of radiant energy in two adjacent wavelength bands, reducing dependence on the absolute value of radiant energy. It is more advantageous when the object being measured is small and cannot fill the field of view, the monochromatic infrared emissivity of the object is low, or there is a glass window obstructing the view between the object and the dual-color infrared thermometry device.

[0003] High-temperature materials, such as alloys, typically exhibit high reactivity. Under conventional casting conditions, contact between these materials and the container walls introduces impurities, affecting their physicochemical processes, such as solidification. The space environment, characterized by microgravity, containerlessness, and high vacuum, provides a more fundamental and convenient framework for studying the mechanisms of rapid solidification through deep supercooling of alloys. In November 2022, with the successful docking of the "Mengtian" module and the "Tianhe" core module, the Chinese space station completed its overall construction. Prior to this, the containerless materials experiment cabinet located within the "Tianhe" core module had already conducted some containerless materials experiments.

[0004] The containerless materials experiment on the space station has the following limitations:

[0005] (1) Due to limitations in satellite communication and security considerations, the duration of a single containerless material experiment on the space station is only 30-50 minutes. Figure 2 The experimental procedure for containerless materials on the space station is given. This means that the sample cannot be heated multiple times in the same containerless materials experiment. Therefore, the complete heating temperature data measured under multiple two-color infrared slopes cannot be obtained in the same containerless materials experiment on the space station.

[0006] (2) Due to the time required for data transmission and processing, detailed temperature data from the space station containerless material experiment usually needs to be downloaded to the ground server 12 hours after the experiment is completed.

[0007] (3)At present, the space station containerless material experiment can only rely on multiple changes in parameters to test, so as to determine the accurate two-color infrared slope. If the two-color infrared slope is changed at intervals of 0.01 in the interval of 0.91-1.15, it needs to be changed dozens of times to obtain a more accurate two-color infrared slope. However, due to the limitation of the number of 29 samples per box in the space station containerless material experiment, if the two-color infrared temperature is calibrated by relying on this method, a large amount of space station containerless material experiment resources will be wasted.

[0008] The above factors result in the inability to quickly determine the slope for two-color infrared measurement, thereby resulting in the inability to guide the experimental operation according to the real-time downloaded rough temperature data during the experiment, which greatly reduces the efficiency of the space station containerless material experiment. In summary, it is necessary to calibrate the two-color infrared temperature obtained by the space station containerless material experiment and quickly predict the two-color infrared slope.

[0009] Patent No. CN102620833B (hereinafter referred to as “Patent 1”) discloses an infrared temperature measurement method and an infrared temperature measurement system, which can calibrate the two-color infrared temperature, but is only applicable to the case of a measured object with a surface covering layer or in contact with a window. Its feature is to compare the temperature of the surface covering layer or the window measured by the thermocouple with the temperature corresponding to the radiation intensity of the surface covering layer or the window obtained by using the infrared temperature measurement device. If it is within the error range, it is considered that the temperature corresponding to the radiation intensity of the measured object measured by the infrared temperature measurement device is the actual temperature of the measured object. However, in the space station containerless material experiment, the measured sample is in an electrostatic suspension state, and the presence of the electrostatic field can cause the thermocouple to fail to work, and the sample does not contact any other device, which also results in the temperature of the observation window being almost constant, i.e., the corresponding relationship between the radiation intensity and the temperature of the window cannot be associated with the corresponding relationship between the radiation intensity and the temperature of the sample to be measured.

[0010] Patent No. CN106768380B (hereinafter referred to as “Patent 2”) discloses a method for calibrating the test results of an infrared temperature measurement device, which is characterized by pre-setting a test model, a calculation formula, and function variables corresponding to the test model and the formula, then fitting the measured values to determine the coefficients and multipliers of the calculation formula, thereby forming a complete calculation formula. However, this method needs to measure the temperature at multiple positions and multiple temperatures by using a thermocouple to ensure the accuracy of the model, and needs to re-fit the parameters after replacing samples of different compositions. In the space station containerless material experiment, the electrostatic field can cause the thermocouple to fail, so the method cannot be used to construct a two-color infrared temperature measurement model. SUMMARY

[0011] TECHNICAL PROBLEM TO BE SOLVED

[0012] In order to avoid the deficiencies of the prior art, the present application provides a two-color infrared temperature calibration method for space station containerless material experiments, which obtains the temperature change of the space station containerless material experiments. The method first needs to obtain the sample heating temperature-time curve measured at a preset two-color infrared slope, then marks the characteristic temperature on the temperature-time curve, and according to the single-color radiant intensity ratio invariable relationship, the two-color infrared slope, the characteristic temperature and the phase change temperature obtained through the phase diagram or thermal analysis experiment are substituted into the established equation relationship. The corrected value of the two-color infrared slope is solved, the corrected value is substituted back into the equation relationship, and all the obtained temperature data are substituted into the equation relationship one by one to solve the corresponding calibrated temperature. Thus, the corrected two-color infrared slope and the calibrated temperature-time curve are obtained.

[0013] Technical scheme

[0014] A two-color infrared temperature calibration method for space station containerless material experiments, characterized by the following steps:

[0015] Step 1, determining the detection wavelength of the two-color infrared temperature measurement equipment:

[0016] Case 1: If the single-channel measurement wavelengths λ1 and λ2 of the given two-color infrared temperature measurement equipment are exact values, then the given values are used as the values of λ1 and λ2;

[0017] Case 2: If the given λ1 and λ2 are range values, then in order to ensure the accuracy of the characteristic temperature after correcting the slope, the corresponding λ1 and λ2 are selected by the following method:

[0018]

[0019] Where: λ * is the wavelength value to be solved, λ a and λ b are the lower limit and upper limit of the given wavelength range, respectively, in units of m; T p is the characteristic temperature obtained from the phase diagram or thermal analysis experiment, in units of K; A and B are constants;

[0020] λ * is a constant between λ a and λ b , which determines the detection wavelengths λ1 and λ2 of the two-color infrared temperature measurement equipment;

[0021] Step 2: correcting the two-color infrared slope at the characteristic temperature to obtain the corrected two-color infrared slope:

[0022]

[0023] Wherein: s' is the modified two-color infrared slope, s is the original two-color infrared slope, is a dimensionless quantity with a value near 1.00; λ1, λ2 are the detection wavelengths of the two single-color infrared channels, with units of m; T m is the characteristic temperature on the original temperature curve, T p is the characteristic temperature corresponding to T m obtained from a phase diagram or thermal analysis experiment, both with units of K;

[0024] Step 3. Calibrate all temperatures according to the modified two-color infrared slope:

[0025] Step 3.1: Substitute the modified two-color infrared slope obtained in Step 2 into the following formula:

[0026]

[0027] Wherein: T1 is the original temperature data obtained at slope s, with units of K; T2 is the calibrated temperature corresponding to T1 at slope s', with units of K;

[0028] Obtain the calibrated temperature:

[0029]

[0030] Step 3.2: Substitute the original temperature data obtained at slope s one by one into Step 3.1 to obtain all the calibrated temperature data.

[0031] The constant A = 2πhc 2 , where π is the circular constant, h is the Planck constant, c is the speed of light, and k is the Boltzmann constant.

[0032] The constant , where h is the Planck constant, c is the speed of light, and k is the Boltzmann constant.

[0033] The modified two-color infrared slope s' is obtained according to the single-color radiance ratio invariance relationship:

[0034] Step 2.1: Single-color radiance of a single infrared channel:

[0035]

[0036]

[0037] Wherein: M(T) is the single-color radiance, with units of W·m -2 ; T is the temperature, with units of K; λ1, λ2 are the measurement wavelengths of the single channel, with units of m; ε is the emissivity corresponding to the corresponding wavelength, which is a dimensionless quantity between 0 and 1; δλ1, δλ2 are the actual measurement wavelength intervals of λ1 and λ2, respectively, with units of m;

[0038] Step 2.2: Based on the actual situation The radiance ratio of the two monochromatic infrared channels is obtained:

[0039]

[0040] Step 2.3: Based on the above formula and the unchanged relationship between the monochromatic radiance ratio before and after calibration, the following relationship is obtained:

[0041]

[0042] Where λ1 and λ2 are the detection wavelengths of the two monochromatic infrared channels, respectively, in meters (m); T m T represents the characteristic temperature on the original temperature curve. p The corresponding T obtained from phase diagrams or thermal analysis experiments m The characteristic temperatures are all in Kelvin (K).

[0043] Step 2.4: Define the two-color infrared slope s:

[0044]

[0045] Based on the above formula and the relationship in step 2.3, we obtain:

[0046]

[0047] Corrected dual-color infrared slope:

[0048]

[0049] Where s is the original two-color infrared slope, a dimensionless quantity with a value around 1.00; s′ is the corrected two-color infrared slope.

[0050] The basic principles for selecting the characteristic temperature are: 1. If there are multiple phase transitions within the study temperature range of the object under study, then one of the phase transition temperatures shall be selected as the characteristic temperature; 2. If there are no phase transitions within the study temperature range of the object under study, then the phase transition temperature closest to the midpoint of the study temperature range shall be selected as the characteristic temperature.

[0051] Beneficial effects

[0052] This invention proposes a two-color infrared temperature calibration method for containerless material experiments on space stations. It utilizes the temperature measurement principle of two-color infrared and combines characteristic temperatures to calibrate temperatures measured at a slope of s using two-color infrared. The process includes the following steps: (1) Marking the characteristic temperature T on the temperature curve obtained at slope s. m (The inflection point on the temperature curve is caused by a material phase change, rather than by a change in heating power); (2) Determine the temperature curve relative to T given by thermal analysis experiments or phase diagrams, etc.m corresponding characteristic temperature T p ; (3) obtaining a mathematical relationship containing s, T m and T p , and solving the corrected two-color infrared slope s' determined by the characteristic temperature T p ; (4) obtaining a mathematical relationship containing s, s' and the original temperature T1, and solving the calibrated temperature T2. For the space station containerless material experiment of Zr-V alloy, the calibration method of the application is used to obtain the corrected slope and the calibrated value of the original temperature, and its accuracy is verified.

[0053] The application calibrates the existing temperature data with the characteristic temperature, and can obtain the corrected two-color infrared slope and the calibrated temperature, solving the calibration problem of the two-color infrared temperature obtained by the space station containerless material experiment. In addition, the method proposed by the application helps to realize the rapid calibration of the two-color infrared slope of the space station containerless material experiment, and improves the efficiency of the space station containerless material experiment. Compared with the method disclosed in patent 1, the method proposed by the application does not need to use a thermocouple, avoiding the failure of the thermocouple in the electrostatic field, and the method proposed by the application can obtain an accurate two-color infrared slope, providing guidance for quickly and accurately obtaining the temperature change of the space station containerless material experiment. Compared with the method disclosed in patent 2, the method proposed by the application does not need to use a thermocouple, does not need to construct a model under the same environment in advance and fit parameters, and the two-color infrared temperature calibrated by the method proposed by the application can be controlled within a small error range at the characteristic temperature. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a flowchart of a two-color infrared temperature calibration method for a space station containerless material experiment.

[0055] Figure 2 is a flowchart of a space station containerless material experiment.

[0056] Figure 3 is a temperature-time curve of the heating process when the slope is 0.98: (a) before calibration, the characteristic temperature is 1601K; (b) after calibration, the characteristic temperature is 1538K.

[0057] Figure 4 is a temperature-time curve of the cooling process when the slope is 0.98: (a) before calibration, the characteristic temperature is 1601K; (b) after calibration, the characteristic temperature is 1538K.

[0058] Figure 5 is a temperature-time curve of the heating process when the slope is 1.00: (a) before calibration, the characteristic temperature is 1582K; (b) after calibration, the characteristic temperature is 1538K.

[0059] Figure 6 The temperature-time curves for the heating process with a slope of 1.05 are: (a) characteristic temperature of 1538K; (b) characteristic temperature of 1535K.

[0060] Figure 7 The temperature-time curves for the cooling process at a slope of 1.05 are: (a) characteristic temperature is 1543K; (b) characteristic temperature is 1531K. Detailed Implementation

[0061] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0062] The technical solution of this invention to solve its technical problem is: a two-color infrared temperature calibration method for containerless material experiments on space stations, characterized by including the following steps:

[0063] Step 1: Determine the detection wavelength of the dual-color infrared thermometer:

[0064] 1. If the given single-channel measurement wavelengths λ1 and λ2 of the dual-color infrared thermometer are exact values, then the given values ​​are used as the values ​​of λ1 and λ2.

[0065] 2. If λ1 and λ2 are given as range values, then to ensure the accuracy of the characteristic temperature after slope correction, the corresponding λ1 and λ2 should be selected as follows:

[0066]

[0067] Where, λ * λ is the wavelength value to be determined, in meters (m). a , λ b These represent the lower and upper limits of a given wavelength range, respectively, in meters (m); T p The characteristic temperature is obtained from the phase diagram or thermal analysis experiment, and the unit is K; A and B are constants, given by equations (2) and (3), respectively. According to the mean value theorem, λ... * It must be between λ a With λ b The constants between these constants allow us to determine the detection wavelengths λ1 and λ2 of the dual-color infrared thermometer.

[0068] A = 2πhc 2 (2)

[0069]

[0070] Where π is the mathematical constant of a circle, h is Planck's constant, c is the speed of light, and k is Boltzmann's constant.

[0071] Step two, according to the single-color radiance ratio invariable relationship, correct the two-color infrared slope at the characteristic temperature:

[0072] 1. Single-color radiance of single infrared channel:

[0073]

[0074]

[0075] Wherein, M(T) is the single-color radiance, unit is W·m -2 ; T is temperature, unit is K; λ1, λ2 is the measured wavelength of single channel, unit is m; ε is the emissivity corresponding to the corresponding wavelength, which is a dimensionless quantity between 0-1; δλ1, δλ2 are the actual measured wavelength interval of λ1, λ2 respectively, unit is m.

[0076] 2. Determine the radiance ratio of two-color infrared:

[0077] Because of the actual situation:

[0078]

[0079] From formula (4), formula (5) and formula (6), the radiance ratio of two single-color infrared channels is obtained:

[0080]

[0081] 3. According to formula (7) and the invariable relationship of single-color radiance ratio before and after calibration, the following relationship is obtained:

[0082]

[0083] Wherein, λ1, λ2 are the detection wavelengths of two single-color infrared channels, unit is m; T m is the characteristic temperature on the original temperature curve, T p is the characteristic temperature corresponding to T m obtained from phase diagram or thermal analysis experiment, unit is K.

[0084] 4. Define two-color infrared slope s:

[0085]

[0086] 5. From formula (8) and formula (9):

[0087]

[0088] Wherein, s is the original two-color infrared slope, which is a dimensionless quantity with a value near 1.00; s' is the corrected two-color infrared slope.

[0089] 6. Obtain the modified two-color infrared slope from equation (10):

[0090]

[0091] Step three, calibrate all temperatures according to the modified two-color infrared slope:

[0092] 1. Substitute the modified two-color infrared slope obtained from equation (11) into the following equation:

[0093]

[0094] wherein T1 is the original temperature data obtained at slope s, in K; T2 is the calibrated temperature corresponding to T1 at slope s', in K. Obtain the calibrated temperature from equation (12):

[0095]

[0096] 2. Substitute the original temperature data obtained at slope s into equation (13) one by one to obtain all the calibrated temperature data.

[0097] DETAILED DESCRIPTION, taking the space station containerless material experiment of Zr-V eutectic alloy as an example.

[0098] Step one, determine the characteristic temperature:

[0099] The selection of the characteristic temperature is related to the object and the content of the study. The basic principles for selecting the characteristic temperature are: (1) if there are multiple phase transitions in the temperature range of the object to be studied, then select one of the phase transition temperatures as the characteristic temperature; (2) if there is no phase transition in the temperature range of the object to be studied, then select the phase transition temperature closest to the midpoint of the temperature range as the characteristic temperature. For example, if the high temperature characteristics or solidification characteristics of the sample are to be studied, then the high temperature characteristic temperature of the sample is to be selected. The characteristic temperature of the Zr-V eutectic alloy in this embodiment is selected as the eutectic platform temperature of the Zr-V eutectic alloy, which is determined by the binary Zr-V alloy phase diagram. The characteristic temperature T p is 1538 K.

[0100] Step two, determine the detection wavelength of the two-color infrared temperature measurement device:

[0101] The two-color infrared temperature measurement instrument used in the Chinese space station is a temperature measurement device produced by LumaSense Techbologies Company, and its model is IGAR 12-LO. According to the data provided in its instruction manual, λ1 is 1.28 μm and λ2 is 1.65 μm.

[0102] Step three, select a preset two-color infrared slope (according to the two-color infrared principle, generally select a value near 1.00 as the preset slope), and then obtain the temperature-time curve of the sample under the slope:

[0103] When the slope is 0.98, the characteristic temperature of the heating process and the cooling process is 1601K, respectively as Figure 3 (a) and Figure 4 (a) shows; when the slope is 1.00, the characteristic temperature of the heating process is 1582K, as Figure 5 (a) shows. These two characteristic temperatures are quite different from the characteristic temperature 1538K given by the phase diagram, so the temperatures obtained under these two slopes need to be corrected.

[0104] Step four, correct the two-color infrared slope:

[0105] 1. According to formula (3) and formula (11), first correct the two-color infrared slope. The values of each parameter in formula (3) are: h = 6.62607015 x 10 -34 J·s, c = 2.99792458 x 10 8 m·s -1 , k = 1.380649 x 10 -23 J·K -1 , the above data is from the International Council for Science Committee on Data for Science and Technology (CODATA) published in 2019; when s is 0.98, the values of each parameter in formula (11) are: s1 = 0.98, T m1 = 1601K, T p = 1538K, λ1 = 1.28μm, λ2 = 1.65μm; when s is 1.00, the values of each parameter in formula (11) are: s2 = 1.00, T m2 = 1582K, T p = 1538K, λ1 = 1.28μm, λ2 = 1.65μm.

[0106] 2. Respectively get the corrected two-color infrared slopes s1' = 1.045, s2' = 1.047 corresponding to s1 = 0.98, s2 = 1.00.

[0107] Step five, calibrate the original temperature:

[0108] According to formula (13), calibrate all the temperature data. Figure 3 (b)、 Figure 4 (b)、 Figure 5 (b) respectively gives the corresponding Figure 3 (a)、 Figure 4 (a)、 Figure 5The temperature-time calibration curve of (a).

[0109] Step six, verify the revised slope and the calibrated temperature. Figure 6 A two-color infrared temperature calibration method according to the present application is given, and a temperature-time curve obtained in the experiment at a slope of 1.05 is taken as an example; Figure 7 A temperature-time curve obtained in the experiment at a slope of 1.05 is given. At this slope, the characteristic temperatures of the temperature rising process and the temperature falling process obtained in the space station without container material experiment are consistent with the characteristic temperatures given by the phase diagram, and the differences are within the error range of 0.5%.

Claims

1. A two-color infrared temperature calibration method for space station containerless material experiments, characterized by The steps are as follows: Step 1, determining the detection wavelength of the dual-color infrared temperature measuring device: Case 1: If the given dual-color infrared thermometry device's single channel measurement wavelength λ 1, λ 2 is an exact value, then use the given value as the value of λ 1, λ 2; Case 2: If the given λ 1、 λ 2 is a range value, in order to ensure the accuracy of the feature temperature after the correction of the slope, the corresponding λ 1、 λ 2 is selected by the following way: wherein: λ * is the wavelength value to be determined, λ a , λ b are the lower and upper limits of the given wavelength range, respectively, in m; T p is a characteristic temperature obtained from a phase diagram or a thermal analysis experiment, in K; A, B are constants. λ * for between λ a and λ b a constant between λ 1 and λ 2; Step 2: correcting the dual-color infrared slope at the characteristic temperature to obtain the corrected dual-color infrared slope: wherein: s′ is the modified two-color infrared slope, s is the original two-color infrared slope, is a dimensionless quantity with a value near 1.00; λ 1、 λ 2 are the detection wavelengths of the two single-color infrared channels, respectively, in m; T m is a characteristic temperature on the original temperature curve, T p is the corresponding T m characteristic temperature, both in K; The dual-color infrared slope s is defined as: Wherein: ε is the emissivity corresponding to the corresponding wavelength; Step 3, calibrating all temperatures according to the corrected dual-color infrared slope: Step 3.1: substitute the corrected dual-color infrared slope obtained in step 2 into the following formula: wherein: T 1 is the slope s the raw temperature data obtained below, in K; T 2 is the slope s′ corresponding T 1 to the calibrated temperature, in K; To obtain the calibrated temperature: Step 3.2: The raw temperature data obtained in Step 3.1 is substituted into the equation for slope s obtained in Step 3.1 to obtain all of the calibrated temperature data.

2. The two-color infrared temperature calibration method for containerless material experiments in space stations according to claim 1, characterized in that: the constant wherein, π is the ratio of the circumference of a circle to its diameter, h is Planck's constant, c is the speed of light, k is Boltzmann's constant.

3. The two-color infrared temperature calibration method for containerless material experiments in space stations according to claim 1, characterized in that: the constant wherein, h is the Planck constant, c is the speed of light, k is the Boltzmann constant.

4. The two-color infrared temperature calibration method for containerless material experiments in space stations according to claim 1, characterized in that: The modified two-color infrared slope s′ According to the single-color radiance ratio invariant relation, we have Step 2.1: monochromatic radiance of a single infrared channel: wherein: M (T) is the monochromatic radiance in W m -2 ; T is the temperature in K; λ 1, λ 2 is the measured wavelength of the individual channel in m; ε is the emissivity corresponding to the respective wavelength, being a dimensionless quantity between 0 and 1; δλ 1, δλ 2 are the actual measured wavelength intervals of λ 1, λ 2 in m; Step 2.2: Depending on the actual situation , the radiance ratio of the two monochromatic infrared channels is obtained: Step 2.3: according to the above formula and the relationship that the ratio of monochromatic radiance before and after calibration remains unchanged, the following relationship is obtained: wherein, λ 1、 λ 2are the detection wavelengths of the two monochromatic infrared channels, respectively, in m; T m T0is a characteristic temperature on the original temperature curve, T p T0is a characteristic temperature on the original temperature curve, T m T0is a characteristic temperature on the original temperature curve, Step 2.4: Defining the two-color infrared slope s : According to the above formula and the relationship of step 2.3, we get: The corrected dual-color infrared slope is obtained: wherein, s is the original two-color infrared slope, which is a dimensionless quantity with a value near 1.00; s′ is the modified two-color infrared slope.

5. The two-color infrared temperature calibration method for containerless material experiments in space stations according to claim 1, characterized in that: The basic principles for selecting the characteristic temperature are:

1. If there are multiple phase changes in the research temperature range of the object being studied, select one of the phase change temperatures as the characteristic temperature; 2. If there is no phase change in the research temperature range of the object being studied, select the phase change temperature closest to the midpoint of the research temperature range as the characteristic temperature.

Images