Method and device for measuring transient thermal field of moving target of solar simulator concentrated light beam energy distribution characteristics

Abstract

The application relates to a moving target transient thermal field measurement method and device for the energy distribution characteristics of a concentrated light beam of a solar simulator, and relates to the field of concentrated solar high-temperature heat utilization. In the prior art, the number of unknowns to be inverted is much larger than the number of equations in the method for acquiring the light beam radiation intensity distribution, and the inversion accuracy is difficult to guarantee. The technical scheme provided by the application is as follows: a moving target transient thermal field measurement method for the energy distribution characteristics of a concentrated light beam of a solar simulator, the method comprising the following steps: collecting the transient temperature field data of test target surfaces at different positions in the optical axis direction of the solar simulator and the spectral radiation force distribution data on the solar simulator; obtaining the energy flow distribution inversion results of the concentrated light at different target positions; obtaining a zero matrix according to the energy flow distribution inversion results of the concentrated light at different target positions; and obtaining the radiation intensity inversion results according to the energy flow distribution inversion results at different target positions and the zero matrix. The application is suitable for the measurement of the spatial distribution characteristics of a concentrated light beam of a solar simulator.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of concentrated solar high-temperature heat utilization, in particular to the measurement of spatial distribution characteristics of a concentrated light beam of a solar simulator. BACKGROUND

[0002] The spatial distribution characteristics of a concentrated light beam refer to the characteristics of spot energy flow density distribution and incident radiation intensity distribution. According to the principle of radiation heat exchange, the incident light energy flow density is equal to the integral of the incident radiation intensity over a 2π spatial solid angle. For the design of a solar high-temperature heat conversion device, it is not enough to only know the spot energy flow density distribution, but also to accurately obtain the radiation intensity distribution.

[0003] Accurate characterization of the incident characteristics of concentrated light is the basis for the design and testing of a solar heat conversion device. The current widely used energy flow measurement method still has some deficiencies, for example: the calibration spectrum of the heat flow meter is inconsistent with sunlight, which introduces errors, and further calibration work is required to overcome. The whole calibration process is complicated; the heat flow meter will interfere with the light field of the measured surface, and the data measured is not a point, but related to the heat flow meter probe.

[0004] There are two methods to obtain the spatial direction distribution of the light beam: (1) an optical model is established for all links from the light source to the concentrator, and then light tracing is performed based on the Monte Carlo method to indirectly obtain the direction information of the light beam. This method is heavily dependent on the accuracy of the modeling of the light concentration system, and it is difficult to implement for artificial light sources such as high-energy xenon lamp solar simulators with complex structures. (2) Based on the basic principle that the radiation intensity is constant in the direction of light propagation, the mapping relationship between the radiation intensity and the heat flow density is constructed through the multi-plane energy flow density distribution, and then the radiation intensity distribution of the light beam is obtained by solving the equation combined with appropriate regularization method. However, the number of unknowns to be inverted will be much larger than the number of equations, and the inversion accuracy is difficult to guarantee, therefore, the research on this test method is very few, and the reliability of the test verification is insufficient, there is no effective method to directly obtain the radiation intensity distribution from the spot distribution, and this method needs to be further improved. SUMMARY

[0005] In view of the problem in the prior art that in the existing method for obtaining the radiation intensity distribution of a light beam, the number of unknowns to be inverted is much larger than the number of equations, the inversion accuracy is difficult to guarantee, therefore, the research on this test method is very few, and the reliability of the test verification is insufficient, there is no effective method to directly obtain the radiation intensity distribution from the spot distribution, the technical solution provided by the present application is as follows:

[0006] The present application provides a method for measuring the energy distribution characteristics of a concentrated light beam of a solar simulator by using a moving target and a transient heat field, which comprises the following steps:

[0007] Step 1: Collecting the transient temperature field data of the test target surface at different positions in the direction of the optical axis of the solar simulator;

[0008] Step two: collecting spectral irradiance distribution data on the solar simulator;

[0009] Step three: obtaining the energy flux distribution inversion result of the concentrated light at different target positions according to the spectral irradiance distribution data and the temperature data;

[0010] Step four: obtaining the zeroing matrix according to the energy flux distribution inversion result of the concentrated light at different target positions;

[0011] Step five: obtaining the irradiance inversion result according to the energy flux distribution inversion result at different target positions and the zeroing matrix.

[0012] Further, a preferred embodiment is provided, wherein in the step three, the method for obtaining the inversion result is: establishing a three-dimensional heat conduction inversion problem model.

[0013] Further, a preferred embodiment is provided, wherein the model is a three-dimensional heat conduction inversion problem model with semi-infinite thickness in the thickness direction.

[0014] Further, a preferred embodiment is provided, wherein the method for obtaining the zeroing matrix is: establishing a solar simulator geometric model and performing concentrated light beam bidirectional transmission tracking simulation calculation, constructing a mathematical model of the relationship between the irradiance and the energy flux density distribution, and counting the zeroing matrix.

[0015] Based on the same inventive concept, the present application also provides a mobile target transient thermal field measurement device for measuring the energy distribution characteristics of a concentrated light beam of a solar simulator, characterized in that the device comprises:

[0016] Module one: used for collecting the transient temperature field data of the test target surface at different positions in the optical axis direction of the solar simulator;

[0017] Module two: used for collecting the spectral irradiance distribution data on the solar simulator;

[0018] Module three: used for obtaining the energy flux distribution inversion result of the concentrated light at different target positions according to the spectral irradiance distribution data and the temperature data;

[0019] Module four: used for obtaining the zeroing matrix according to the energy flux distribution inversion result of the concentrated light at different target positions;

[0020] Module five: used for obtaining the irradiance inversion result according to the energy flux distribution inversion result at different target positions and the zeroing matrix.

[0021] Further, a preferred embodiment is provided, wherein the module three further comprises a sub-module for establishing a three-dimensional heat conduction inversion problem model.

[0022] Further, a preferred embodiment is provided, wherein the model is a three-dimensional heat conduction inverse problem model with semi-infinite thickness in the thickness direction.

[0023] Further, a preferred embodiment is provided, wherein the module four further comprises a sub-module for establishing a solar simulator geometric model and performing a concentrated light beam bidirectional transmission tracking simulation calculation, constructing a mathematical model of the radiation intensity and energy flow density distribution relationship, and statistically reducing a zero matrix.

[0024] Based on the same inventive concept, the present application also provides a computer storage medium for storing a computer program for being read by a computer to enable the computer to perform the moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of the solar simulator.

[0025] Based on the same inventive concept, the present application also provides a computer comprising a processor and a storage medium for storing a computer program for being read by the processor to enable the computer to perform the moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of the solar simulator.

[0026] Compared with the prior art, the technical solution provided by the present application has the following advantages:

[0027] At present, the energy distribution characteristics of the concentrated light beam are widely measured based on the energy flow measurement method, and there are problems such as spectral deviation of the heat flow meter calibration and interference to the test surface; among them, the measurement of the directional distribution characteristics of the concentrated light beam seriously depends on the modeling of the light condensing system, and it is difficult to implement for a high-energy flow xenon lamp solar simulator which is a complex artificial light source, and there is no effective method for directly obtaining the radiation intensity distribution of the exit surface from the spot energy flow density distribution.

[0028] The moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of the solar simulator provided by the present application has the characteristics of high resolution and simple required device, and can realize non-interference measurement; the method for directly obtaining the radiation intensity distribution of the exit surface from the spot distribution reduces the dependence on the accuracy of the model construction.

[0029] The present application is suitable for the working of the measurement of the spatial distribution characteristics of the concentrated light beam of the solar simulator. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The flowchart of the moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of the solar simulator provided by the fourth embodiment is shown in the figure.

[0031] Figure 2 The component diagram of the moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of the solar simulator mentioned in the third embodiment is shown in the figure.

[0032] Figure 3 The flowchart of the energy flow density distribution inversion of the concentrated light at different target positions in step S3 of the moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of the solar simulator mentioned in embodiment four;

[0033] Figure 4 The flowchart of the mathematical model of the relationship between the radiation intensity and the energy flow density distribution constructed by the bidirectional ray tracing of the concentrated light in step S4 of the moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of the solar simulator mentioned in embodiment four;

[0034] In the figure, 1 represents an infrared thermal imager, 2 represents a test target, 21 represents a target body, 22 represents thermal insulation material, 23 represents an outer shell, 3 represents an electric linear module, 4 represents a lifting platform, 5 represents a light shield, 6 represents a thermocouple, and 7 represents a computer. DETAILED DESCRIPTION

[0035] In order to make the advantages and beneficial effects of the technical solutions provided by the present application more clear, the technical solutions provided by the present application are further described in detail in combination with the drawings, and specifically:

[0036] Embodiment one provides a moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of a solar simulator, and the method comprises the following steps:

[0037] Step one: collecting transient temperature field data of a test target surface at different positions in the direction of the optical axis of a solar simulator;

[0038] Step two: collecting spectral radiation force distribution data on the solar simulator;

[0039] Step three: obtaining the energy flow distribution inversion result of the concentrated light at different target positions according to the spectral radiation force distribution data and the temperature data;

[0040] Step four: obtaining a zero matrix according to the energy flow distribution inversion result of the concentrated light at different target positions;

[0041] Step five: obtaining a radiation intensity inversion result according to the energy flow distribution inversion result at different target positions and the zero matrix.

[0042] In step two, the spectral radiation force distribution can be obtained by searching technical documents or data from a xenon lamp manufacturer;

[0043] Preferably, the distribution data is actually measured.

[0044] Embodiment two, the embodiment is further limited to the moving target transient thermal field measurement method of the solar simulator concentrated light beam energy distribution characteristics provided in embodiment one, in the step three, the acquisition method of the inversion result is: establishing a three-dimensional heat conduction inversion problem model.

[0045] Embodiment three, in combination Figure 2 The embodiment is further limited to the moving target transient thermal field measurement method of the solar simulator concentrated light beam energy distribution characteristics provided in embodiment two, and the model is a three-dimensional heat conduction inversion problem model with semi-infinite thickness in the thickness direction.

[0046] Specifically,

[0047] The components required for measurement include an infrared thermal imager 1, a test target 2, an electric linear module 3, a lifting platform 4, a light shield 5, a thermocouple 6, and a computer 7. The target body 21 of the test target is made of a high-temperature-resistant material with a small thermal diffusion coefficient and known thermal properties, preferably 310S stainless steel, specifically a 150mm x 150mm x 5mm 310S stainless steel plate, the front surface of which is treated with plasma sprayed aluminum oxide, the back surface and the side surface are covered with thermal insulation material 22, preferably 15mm thick, and is fixed in a metal shell 23. The infrared thermal imager 1 has recording function, and the concentrated light spectrum is outside the response waveband, preferably the response waveband is 7-14 microns. The infrared thermal imager is connected to the computer, and the electric linear module can realize precise displacement under the control of the computer, the test target is fixed on the electric linear module, and the light shield 5 is made of polished aluminum alloy, which avoids the interference of unstable light spots on the test target temperature field.

[0048] Before the test of the target surface transient temperature field, the concentrated light is irradiated on the light shield, after the light spot is stable, the light shield is removed, the test target is heated and warmed up, the infrared thermal imager records the data of the target surface transient temperature field, and the test time is 10-15 seconds. The target surface energy flux distribution is written as a linear combination of a group of basis functions:

[0049]

[0050] Where q j represents the target surface concentrated solar energy flux density distribution of the jth target position, r is the position vector, C i (r) is the basis function, a total of N-1, P j ={P i,j} is the absorption heat flux density inversion parameter matrix, a total of M target positions, preferably, C i (r) adopts non-uniform rational B-spline basis function.

[0051] Specifically, in the step one, first, a light shield is erected between the xenon lamp and the target surface. After the xenon lamp is lighted for 5 minutes, the voltage and current values are stable, the thermal imager starts recording, and then the light shield is removed. After the test lasts for about 15 seconds, the xenon lamp is turned off and the data collection of the thermal imager is terminated, and the transient temperature field data of the test target surface are saved. Under the control of the computer, the translational displacement unit is displaced by a certain distance along the optical axis direction of the condensing system through the mechanical control system. The above operation is repeated to obtain the transient temperature field data of the test target surface at different positions.

[0052] Step S3 includes the following steps:

[0053] (S31). A positive problem solving model in a three-dimensional heat conduction inversion problem model is established, and the control equation and the fixed solution condition are as follows:

[0054]

[0055] Wherein, Ω represents the target body calculation domain of the test target, Γ m represents the front surface of the test target, Γ o represents other boundaries of the test target, ρ, c p , k c are the density, specific heat and thermal conductivity of the target material respectively, h f is the boundary convective heat transfer coefficient, λ is the wavelength, ε λ is the emissivity of the front surface of the test target, T0 and T a are the initial temperature and the ambient temperature respectively, τ represents time, T represents temperature, n represents the outer normal of the boundary, q represents the heat flow distribution of the target surface, E bλ represents the blackbody spectral radiation force.

[0056] (S32). Based on the target surface transient thermal image photographed by the infrared thermal imager 1, image correction is carried out, and the discretized target surface transient temperature field is extracted. Wherein

[0057]

[0058] Wherein represents the temperature value of the target surface unit i at the kth time layer under the jth target position, there are N e units on the target surface, and N t time layers are experienced each time.

[0059] (S33). Based on the dimensionless temperature field Θ(r∈Γ m , δτ) at the δτ moment in the initial stage of temperature rise, the initial guess field q j (r) of the target surface energy flow density absorption distribution is constructed. max,j j ​(r, δτ), preferably, the dimensionless temperature field takes the form of:

[0060]

[0061] where max[·] and min[·] denote the maximum and minimum, respectively.

[0062] (S34). Parameterizing the initial guess field as a pre-inversion process, firstly, the dimensionless temperature field Θ j (r, δτ) is fitted to obtain the initial parameters Then, the initial guess field proportional coefficient q max,j is inverted with the transient temperature field T m as input, and the parameter constraint condition is determined according to the total input solar energy Q sun of the aggregation system, and the mathematical expressions of the objective function and the constraint condition are as follows:

[0063]

[0064]

[0065] (S35). With the pre-inversion parameter result as the initial value, the transient temperature field T m as input, the final result can be inverted based on the particle swarm optimization algorithm, and the mathematical expressions of the objective function and the constraint condition are as follows:

[0066]

[0067]

[0068] The target surface energy flux density absorption distribution q j (r) is further combined with the target surface spectral absorptivity α λ and the aggregation light radiation force spectral distribution f λ to calculate the aggregation light energy flux density distribution G j (r):

[0069]

[0070] Embodiment Four, in combination with Figure 3 and 4 This embodiment is a further limitation of the mobile target transient thermal field measurement method for the energy distribution characteristics of the solar simulator aggregated light beam provided in any one of embodiments one to three, and the acquisition method of the zero matrix is: establishing a geometric model of a solar simulator and performing a two-way transmission tracking simulation calculation of an aggregated light beam, constructing a mathematical model of the relationship between radiation intensity and energy flux density distribution, and counting the zero matrix.

[0071] Specifically:

[0072] The infrared thermal imager is connected to a computer. The motorized linear module can achieve precise displacement under computer control. The test target is fixed to the motorized linear module. The light shield 5 can be made of polished aluminum alloy to prevent unstable light spots from interfering with the temperature field of the test target. Step S4 uses the multi-target position to gather the light flux density distribution and combines it with the zeroing matrix to invert the radiation intensity distribution of the test surface. The radiation intensity test surface can be any of the target positions; the rest are called reference surfaces. Step S4 includes:

[0073] (S41). Discretize the measured surface and the reference surface in space, and the spatial grid N r The concentrated light energy flux density distribution G obtained in step S33 is j (r) Perform discretization processing to obtain the concentrated light energy flux density G in the k-th spatial grid of target position j j,k , discretize the solid angle of the space grid unit of the measured surface, the zenith angle step Δθ, the circular angle step The radiation intensity vector to be inverted is I, elements.

[0074] (S42) Using the Monte Carlo method, in each solid angle unit, the absorption of light on the parallel target surface is counted, and the radiation intensity I and energy flux density distribution G are listed. k,j Mathematical model of the relationship:

[0075]

[0076] in N represents the number of rays that are absorbed by spatial unit k on the target plane j starting from the solid angle unit (i, m, n) of the surface to be measured. i,m,n represents the total number of rays sampled within the solid angle unit (i,m,n), θ m represents the zenith angle, The above formula can be organized into a linear algebraic equation system AI=G for the radiation intensity I.

[0077] (S43) Using the reverse Monte Carlo method, randomly sample light in each solid angle and trace it backwards. If the light in the solid angle cannot return to the light source area, record the solid angle number to assemble the zero matrix A. eq , through the equality constraint A eq I=0 sets the radiation intensity within this solid angle to zero.

[0078] Step S5 uses the multi-target aggregated light energy flow density distribution, the mathematical model of the relationship between the radiation intensity and the energy flow density distribution, and the zero matrix to obtain the radiation intensity distribution of a certain to-be-measured surface by using the Tikhonov regularization non-negative constraint least square method inversion, and the mathematical expressions of the objective function and the constraint condition are as follows:

[0079]

[0080] s.t. I>0

[0081] A eq I=0 ;

[0082] wherein the parameter α>0 is a regularization coefficient.

[0083] Embodiment five, the embodiment provides a moving target transient thermal field measurement device for the energy distribution characteristics of a concentrated light beam of a solar simulator, and the device comprises:

[0084] Module one: used for collecting transient temperature field data of a test target surface at different positions in the direction of an optical axis of a solar simulator;

[0085] Module two: used for collecting spectral radiation force distribution data on the solar simulator;

[0086] Module three: used for obtaining an energy flow distribution inversion result of concentrated light at different target positions according to the spectral radiation force distribution data and the temperature data;

[0087] Module four: used for obtaining a zero matrix according to the energy flow distribution inversion result of the concentrated light at the different target positions;

[0088] Module five: used for obtaining a radiation intensity inversion result according to the energy flow distribution inversion result at the different target positions and the zero matrix.

[0089] Embodiment six, the embodiment is a further limitation of the moving target transient thermal field measurement device for the energy distribution characteristics of a concentrated light beam of a solar simulator provided in Embodiment five, and the module three further comprises a sub-module used for establishing a three-dimensional heat conduction inversion problem model.

[0090] Embodiment seven, the embodiment is a further limitation of the moving target transient thermal field measurement device for the energy distribution characteristics of a concentrated light beam of a solar simulator provided in Embodiment six, and the model is a three-dimensional heat conduction inversion problem model with a semi-infinite thickness direction.

[0091] Embodiment eight, the embodiment is further limited to the moving target transient thermal field measurement device for the energy distribution characteristics of the concentrated light beam of the solar simulator provided by any one of the embodiments five to eight, and the module four further comprises a sub-module for establishing a geometric model of the solar simulator and performing a two-way transmission tracking simulation calculation of the concentrated light beam, constructing a mathematical model of the distribution relationship between the radiation intensity and the energy flow density, and statistically zeroing the matrix.

[0092] Embodiment nine, the embodiment provides a computer storage medium for storing a computer program, the computer program is used to be read by a computer, so that it executes the moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of the solar simulator provided by any one of the embodiments one to four.

[0093] Embodiment ten, the embodiment provides a computer including a processor and a storage medium for storing a computer program, the computer program is used to be read by the processor, so that the computer executes the moving target transient thermal field measurement method for the energy distribution characteristics of the concentrated light beam of the solar simulator provided by any one of the embodiments one to four.

[0094] The above further describes the technical solutions provided by the present application through several specific embodiments, in order to highlight the advantages and benefits of the technical solutions provided by the present application. However, the above several specific embodiments are only used to further describe the technical solutions provided by the present application, and are not used as the limitation of the present application. Any reasonable changes and improvements, combination and equivalent replacement of the embodiments based on the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A moving target transient thermal field measurement method for the concentrated beam energy distribution characteristics of a solar simulator, characterized in that: The method comprises: Step 1: Collect transient temperature field data of the test target surface at different positions along the optical axis of the solar simulator; The test target is fixed on the electric linear module. The target body is made of a high-temperature resistant material with a small thermal diffusivity and known thermal properties. The front side is treated with plasma sprayed aluminum oxide, and the back and sides are covered with thermal insulation material. Step 2: Collecting spectral radiation distribution data on the solar simulator; Step 3: Obtaining the energy flux distribution inversion results of the focused light at different target positions according to the spectral radiation force distribution data and the temperature field data; The inversion result is obtained based on a three-dimensional heat conduction inversion problem model with semi-infinite thickness direction, which solves the heat flux density distribution through the corresponding relationship between the transient temperature field of the target surface and the incident energy flux density; Step 4: Obtaining a zeroing matrix based on the inversion results of the energy flux distribution of the focused light at different target positions; The method for obtaining the zeroing matrix is ​​as follows: establishing a solar simulator geometric model and performing a concentrated light beam bidirectional transmission tracking simulation calculation, constructing a mathematical model of the relationship between radiation intensity and energy flux density distribution, and calculating the zeroing matrix; Step 5: Obtain radiation intensity inversion results based on the energy flux distribution inversion results at different target positions and the zeroing matrix.

2. A moving target transient thermal field measurement device for the concentrated beam energy distribution characteristics of a solar simulator, characterized in that: The device comprises: Module 1: used to collect transient temperature field data of the test target surface at different positions along the optical axis of the solar simulator; The test target is fixed on the electric linear module. The target body is made of a high-temperature resistant material with a small thermal diffusivity and known thermal properties. The front side is treated with plasma sprayed aluminum oxide, and the back and sides are covered with thermal insulation material. Module 2: used to collect spectral radiation distribution data on the solar simulator; Module three: used to obtain the energy flux distribution inversion results of the concentrated light at different target positions based on the spectral radiation force distribution data and the temperature field data; The inversion result is obtained based on a three-dimensional heat conduction inversion problem model with semi-infinite thickness direction, which solves the heat flux density distribution through the corresponding relationship between the transient temperature field of the target surface and the incident energy flux density; Module 4: used to obtain a zeroing matrix based on the inversion results of the energy flux distribution of the concentrated light at different target positions; The method for obtaining the zeroing matrix is ​​as follows: establishing a solar simulator geometric model and performing a concentrated light beam bidirectional transmission tracking simulation calculation, constructing a mathematical model of the relationship between radiation intensity and energy flux density distribution, and calculating the zeroing matrix; Module 5: used to obtain radiation intensity inversion results based on the energy flux distribution inversion results at different target positions and the zeroing matrix.

3. A computer storage medium for storing a computer program, characterized in that: The computer program is used to be read by a computer to enable the computer to execute the moving target transient thermal field measurement method of the concentrated beam energy distribution characteristics of a solar simulator according to claim 1.

4. A computer comprising a processor and a storage medium for storing a computer program, characterized in that The computer program is used to be read by the processor to enable the computer to execute the moving target transient thermal field measurement method of the concentrated beam energy distribution characteristics of the solar simulator according to claim 1.

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