Method, system and storage medium for reconstructing heat flux density field using scanning electron beam

Abstract

The present invention discloses a method, system and storage medium for reconstructing a heat flux density field by scanning an electron beam. The method comprises the following steps: S1: discretization of scanning points of a target heat flux density field; S2: planning of a scanning trajectory, a scanning field frequency and an electron beam spot radius, wherein the scanning trajectory connects all scanning points in series; S3: performance calibration of a scanning drive system and construction of an ideal current output signal I of the scanning drive system after a Lagrange transformation. t‑s (s) and the actual output current signal I of the scanning drive system r‑s (s) transfer function; S4: Establish the energy balance equations for the scanning points and solve them iteratively. This invention effectively solves the problem that the ideal jump model is difficult to reconstruct the target heat flux density field with high precision under high-frequency scanning conditions. It provides a feasible method for heat flux density field reconstruction conditions that require a large number of scanning points, such as large workpieces, high aspect ratio scanning areas, and large heat flux density gradients. This broadens the engineering application scenarios of scanning electron beam thermal assessment methods.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and in particular to a method, system and storage medium for reconstructing a heat flux density field using a scanning electron beam. Background Art

[0002] Since the first hypersonic flight, ground-based thermal testing has been of paramount importance, a crucial component in ensuring the effectiveness of aerodynamic thermal protection designs. Scanning electron beam thermal testing, an emerging ground-based thermal testing technology, offers significant advantages over traditional quartz lamp array thermal testing methods in creating high-temperature, high-heat-flux, non-uniform, and high-gradient thermal environments. This holds promise for meeting the increasingly stringent thermal testing requirements of hypersonic vehicles.

[0003] Patent publication number CN112719557A discloses a method and apparatus for achieving non-uniform heat flux density distribution using electron beam scanning. This approach ignores the electron beam's jumping process and constructs a method for reconstructing the target heat flux density field, thereby simplifying the solution process of the electron beam scanning strategy. However, this assumption is valid when the response time of the scanning drive system is much smaller than the electron beam's dwell time. In large-scale thermal assessment experiments with multiple dwell points, the dwell time and the response time of the scanning drive system are on the same time scale. In this case, the assumption of ignoring the electron beam's jumping process no longer holds, and the deviation of the reconstructed target heat flux density field will increase dramatically. To solve this problem, it is necessary to construct a method, system, and storage medium for reconstructing the heat flux density field by scanning electron beams. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a method, system and storage medium for reconstructing the heat flux density field by scanning electron beam, which effectively solves the problem that the ideal jump model is difficult to reconstruct the target heat flux density field with high precision under high-frequency scanning conditions. It provides a feasible method for carrying out heat flux density field reconstruction conditions that require a large number of scanning points, such as large workpieces, high aspect ratio scanning areas and large heat flux density gradients, and broadens the engineering application scenarios of the scanning electron beam thermal assessment method.

[0005] The method for reconstructing the heat flux density field by scanning electron beam proposed in the present invention comprises the following steps:

[0006] S1: Discrete scanning points of target heat flux density field;

[0007] S2: planning of scanning trajectory, scanning field frequency and electron beam spot radius, where the scanning trajectory connects all scanning points in series;

[0008] S3: Performance calibration of the scan drive system and construction of the ideal current output signal I of the scan drive system after pull-type conversion t-s (s) and the actual output current signal I of the scanning drive system r-sTransfer function of (s);

[0009] S4: Establish the energy balance equations of the scanning points and solve them iteratively; the specific method is:

[0010] According to the ratio k of the electron beam’s target deflection distance to the output current signal of the scanning drive system and the transfer function S3, the real scanning trajectory time series of the electron beam is obtained. The real scanning trajectory time series of the electron beam is divided into n segments at every interval Δt0. The average scanning position of the electron beam in the jth time period is recorded as (x j ,y j ), the spatial position is (x i ,y i )’s target heat flux density for the i-th unit is as follows:

[0011]

[0012] Where q″ i is the target heat flux density of the i-th unit; ΔQ ij is the total energy absorbed by the i-th unit; P is the total power of the electron beam absorbed by the sample; R is the electron beam spot radius; ΔL is the scanning point spacing.

[0013] Preferably, the electron beam spot radius is equal to the spacing between discrete scanning points.

[0014] Preferably, the scanning system in S3 is an open-loop scanning drive system, a second-order negative feedback scanning drive system, or a higher-order negative feedback scanning drive system.

[0015] Preferably, the iterative solution method in S4 is: set a uniform residence time distribution, compare the average heat flux density at each scanning point with the target heat flux density, if the average heat flux density at the scanning point is lower than the target heat flux density, extend the residence time of the scanning point; if the average heat flux density at the scanning point is higher than the target heat flux density, shorten the residence time of the scanning point; when the absolute value of the reconstruction deviation of the average heat flux density at all scanning points is less than the set reconstruction accuracy, the solution of the scanning point energy balance equation group is completed.

[0016] The present invention proposes a system for reconstructing a heat flux density field by scanning an electron beam, comprising:

[0017] Data processing module, used for discretization of target heat flux density field scanning points;

[0018] Scan strategy planning module, used for planning the scanning trajectory, scanning field frequency and electron beam spot radius, where the scanning trajectory connects all scanning points in series;

[0019] Scan drive module, used for performance calibration of the scan drive system and construction of the ideal current output signal I of the scan drive system after pull-type conversiont-s (s) and the actual output current signal I of the scanning drive system r-s Transfer function of (s);

[0020] The dwell time analysis module is used to establish the energy balance equations at the scanning points and solve them iteratively. The specific method is as follows:

[0021] According to the ratio k of the electron beam’s target deflection distance to the output current signal of the scanning drive system and the transfer function S3, the real scanning trajectory time series of the electron beam is obtained. The real scanning trajectory time series of the electron beam is divided into n segments at every interval Δt0. The average scanning position of the electron beam in the jth time period is recorded as (x j ,y j ), the spatial position is (x i ,y i )’s target heat flux density for the i-th unit is as follows:

[0022]

[0023] Where q″ i is the target heat flux density of the i-th unit; ΔQ ij is the total energy absorbed by the i-th unit; P is the total power of the electron beam absorbed by the sample; R is the electron beam spot radius; ΔL is the scanning point spacing.

[0024] The present invention provides a computer storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the method for reconstructing a heat flux density field by a scanning electron beam are implemented.

[0025] Beneficial technical effects of the present invention:

[0026] The method of reconstructing the heat flux density field of the present invention takes into account the actual jumping process of the electron beam between scanning points, effectively solving the problem that the ideal jumping model is difficult to reconstruct the target heat flux density field with high precision under high-frequency scanning conditions, and provides a feasible method for carrying out heat flux density field reconstruction conditions that require a large number of scanning points, such as large workpieces, high aspect ratio scanning areas and large heat flux density gradients, and broadens the engineering application scenarios of the scanning electron beam thermal assessment method; in addition, the basic principle of scanning electron beams is to simulate stable heat flux density field input through high-frequency scanning. This method can improve the reconstruction accuracy of the target heat flux density field under high-frequency scanning conditions, thereby improving the engineering application reliability of the scanning electron beam thermal assessment method. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The target heat flux density field proposed by the present invention;

[0028] Figure 2 The discrete results of the target heat flux density field scanning points proposed by the present invention;

[0029] Figure 3 The raster scanning track proposed by the present invention;

[0030] Figure 4 The calibration process of the scanning drive system proposed in the present invention;

[0031] Figure 5 This is the calibration result of the scan drive system proposed in the present invention;

[0032] Figure 6 The iterative history of the target heat flux field is reconstructed for the model considering the jump process in Example 1 of the present invention;

[0033] Figure 7 The ideal output current signal of the scanning driving system considering the jump process in embodiment 1 of the present invention;

[0034] Figure 8 This is the actual output current signal of the scanning driving system considering the jump process in embodiment 1 of the present invention;

[0035] Figure 9 This is the result of solving the residence time distribution considering the jump process in Example 1 proposed by the present invention;

[0036] Figure 10 This is the result of the scanning heat flux density field solution considering the jump process in Example 1 proposed by the present invention;

[0037] Figure 11 The target heat flux density field reconstruction deviation distribution considering the jump process in Example 1 proposed by the present invention;

[0038] Figure 12 This is the ideal output current signal of the scanning driving system in which the jump process is ignored in the first embodiment of the present invention;

[0039] Figure 13 This is the actual output current signal of the scanning driving system in which the jump process is ignored in the first embodiment of the present invention;

[0040] Figure 14 This is the dwell time distribution solution result obtained by ignoring the jump process in Example 1 of the present invention;

[0041] Figure 15 This is the result of the scanning heat flux density field solution in Example 1 of the present invention, ignoring the jump process;

[0042] Figure 16 The target heat flux field reconstruction deviation distribution is obtained by ignoring the jump process in Example 1 of the present invention;

[0043] Figure 17 The two-stage reciprocating raster scanning trajectory proposed by the present invention;

[0044] Figure 18 This is the result of solving the residence time distribution considering the jump process in Example 2 proposed by the present invention;

[0045] Figure 19 This is the result of the scanning heat flux density field solution considering the jump process in Example 2 proposed by the present invention;

[0046] Figure 20 The target heat flux field reconstruction deviation distribution considering the jump process in embodiment 2 of the present invention is as follows;

[0047] Figure 21 This is the dwell time distribution solution result obtained by ignoring the jump process in Example 2 of the present invention;

[0048] Figure 22 This is the result of the scanning heat flux density field solution in Example 2 of the present invention, ignoring the jump process;

[0049] Figure 23 This is the target heat flux field reconstruction deviation distribution that ignores the jump process in Example 2 proposed by the present invention. DETAILED DESCRIPTION

[0050] The present invention will be further explained below with reference to specific embodiments.

[0051] Example 1

[0052] Gaussian distribution is usually used to describe the heat flux density field distribution characteristics of the leading edge of a hypersonic aircraft. Figure 1 The target heat flux density field shown is Gaussian distributed. The peak heat flux density of the target heat flux density field is about 10MW / m 2 , size is 40mm×40mm.

[0053] The method for reconstructing the heat flux density field by scanning electron beam proposed in this embodiment has the following steps:

[0054] S1: Discrete scanning points of target heat flux density field.

[0055] 20×20 scanning points are evenly arranged in the scanning area, and the scanning point spacing is 2mm. The discrete results of the target heat flux density field are as follows: Figure 2 shown.

[0056] The discretization of the target heat flux density field scanning points in this embodiment can be accomplished using existing techniques, such as the discretization method described in Patent Publication No. CN112719557A. Both uniform and non-uniform grid discretization methods can be employed; the grid shape is not limited to rectangles and triangles; and the scanning points, in addition to being located at the grid's centroid, can also be located at other locations on the grid according to specific mathematical methods, not limited to the circumcenter, incenter, or orthocenter.

[0057] S2: Planning of scanning trajectory, scanning field frequency and electron beam spot radius.

[0058] Regarding the scanning trajectory, in addition to the raster scanning trajectory of this embodiment, any trajectory connecting all scanning points in series can also be used, not limited to a regular sequential connection, but also a random connection. Furthermore, a large scanning cycle consisting of multiple groups of scanning trajectories can also be used. Regarding the scanning field frequency, it is generally desirable for the scanning electron beam to have a high scanning field frequency, that is, the electron beam completes as many scanning cycles as possible within a certain period of time, in order to utilize the dynamic heating effect of the high-speed scanning electron beam to simulate the stable heating effect of the target heat flux density field. Regarding the beam spot radius, this parameter is usually set equal to the scanning point spacing. Under this condition, the optimal reconstruction accuracy can be achieved for most working conditions.

[0059] The scanning path of this embodiment is as follows Figure 3 The raster scanning shown has a scanning field frequency of 60 Hz, that is, the electron beam passes through all scanning points along the scanning path 60 times per second, and the electron beam spot radius is set to be the same as the scanning point spacing, both of which are 2 mm.

[0060] S3: Performance calibration of the scan drive system and construction of the ideal current output signal I of the scan drive system after pull-type conversion t-s (s) and the actual output current signal I of the scanning drive system r-s The transfer function of (s).

[0061] The driving process of a scanning electron beam can be described as follows: First, a waveform generator converts a digital signal containing dwell time distribution and scanning trajectory information into a voltage excitation signal. This signal is then fed into the scanning drive system, where it is converted into a current signal that drives the coil to generate a time-varying magnetic field. Under this time-varying magnetic field, the electron beam performs a regular, high-speed scanning. The response time of the scanning drive system, which converts the voltage excitation signal into a current drive signal, is the most significant factor affecting the overall system's response performance. Therefore, the performance of the scanning drive system must be calibrated and a transfer function established.

[0062] The scanning drive system used in this embodiment is a typical second-order negative feedback scanning drive system. The ideal current output signal of the scanning drive system is I t(t), which is the ratio of the voltage excitation signal of the scanning drive system multiplied by the power amplifier coefficient and the output loop resistance of the scanning drive system. The actual output current signal of the scanning drive system is I r (t), then after the Latent transformation I t (t) and I r (t) are converted into I t-s (s) and I r-s (s), the transfer function is:

[0063]

[0064] Where, ω n is the natural oscillation frequency; ξ is the damping coefficient. ω can be obtained by fitting the voltage excitation signal, output loop resistance and output current signal of the scanning drive system. n and ξ. The specific fitting process is as follows:

[0065] In order to calibrate the key parameters of the scanning drive system, namely the natural oscillation frequency and damping coefficient, the electron beam is designed to jump once every 2mm with the same dwell time, and the dwell positions are 0mm, 2mm, 4mm and 6mm respectively. Three independent experiments were carried out, with dwell times of 100μs, 50μs and 20μs respectively. The proportional coefficient between the deflection distance of the electron beam and the output current of the scanning drive system is 11A / m. From this, the ideal output current signal of the scanning drive system can be converted. The power amplifier coefficient of the scanning drive system is 1.4, and the output loop resistance is 3.7Ω. Therefore, the excitation voltage signal of the scanning drive system can be calculated based on the ideal output current signal. Figure 4 As shown, the excitation voltage signal is input into the scanning drive system to obtain Figure 5 The black line in the middle shows the measured value of the output current signal. Assuming that the initial values ​​of the natural oscillation frequency and the damping coefficient are both 0.5, the excitation voltage signal is input into the transfer function of the scanning drive system to obtain the calculated value of the output current signal. The measured and calculated results are compared, and the natural oscillation frequency and damping coefficient are iterated. The final calculated value of the output current signal obtained by iteration is shown as follows: Figure 5 As shown by the medium gray line, the natural oscillation frequency and damping coefficient at this time are 0.13918 and 0.31155 respectively.

[0066] In addition, in addition to using the second-order negative feedback scanning drive system of this embodiment, a higher-order negative feedback scanning drive system or an open-loop scanning drive system can also be used. The transfer functions of these scanning drive systems can be calibrated based on the method of the present invention, and the jumping process of the electron beam can be incorporated into the target heat flux density field reconstruction model.

[0067] Regarding the construction of the transfer function of the scanning drive system, in addition to obtaining a specific transfer function by finding a known transfer function and then fitting key parameters in the present embodiment, one can also directly focus on the input and output signals of the scanning drive system and perform function fitting on the response curves between the two to obtain the transfer function of the scanning drive system.

[0068] S4: Establish the energy balance equations of the scanning points and solve them iteratively.

[0069] Based on the discrete unit design of the target heat flux density field in S1 and the scanning trajectory planned in S2, the electron beam scanning trajectory time series is obtained, which is recorded as S t (t). Based on the proportional coefficient between the target deflection distance of the electron beam and the output current signal of the scanning drive system, that is, k = 11A / m, the equation I t (t) = k·S t (t), the ideal current output signal is obtained by conversion. Based on the transfer function established by S3, I t (t) is converted to I r (t), and further combined with the proportional coefficient between the target deflection distance of the electron beam and the output current signal of the scanning drive system, the actual scanning trajectory of the electron beam can be obtained, which is recorded as S r (t). The sequence is divided into 16667 segments at intervals of 1 μs. The average scanning position of the electron beam in the jth time period is recorded as (x j ,y j ). In the j period, the total energy absorbed by the i-th unit is:

[0070]

[0071] The average heat flux absorbed by the i-th unit in a scanning cycle should be equal to the target heat flux, that is:

[0072]

[0073] For the 400 discrete units in S1, 400 of the above equations can be established and the energy balance equations of the scanning points can be obtained by combining them.

[0074] The iterative solution method of the energy balance equations at the scanning points is as follows: the initial dwell time is set to be uniformly distributed, the target reconstruction accuracy is 2%, and the iterative convergence curve is shown in Figure 6. The final ideal current output signal, real output current signal, dwell time distribution, scanning heat flux density field and reconstruction deviation distribution are shown in Figure 6. Figure 7-11 shown. Figure 12-16The reconstruction results of the target heat flux density field of the reconstruction model ignoring the electron beam jumping process under the same reconstruction parameters are given respectively, including the ideal current output signal, the real output current signal, the residence time distribution, the scanned heat flux density field and the reconstruction deviation distribution. Figure 11 and Figure 16 By comparison, compared with the reconstruction model that ignores the electron beam jumping process, considering the electron beam jumping process to analyze the target heat flux density field can reduce the maximum absolute value of the reconstruction deviation from 89.95% to 1.98%, and the optimization range reaches 97.80%.

[0075] Example 2

[0076] In Example 1, the electron beam always scans from left to right. When the electron beam moves to the rightmost end, it will jump significantly to the leftmost end. At this time, the response time of the scanning drive system is relatively long. This scanning trajectory is not conducive to the solution model that ignores the jump process to reconstruct the target heat flux density field with high precision. Therefore, the comparison of the two models in Example 1 is not generally meaningful. This example also compares the two models under the condition of continuous small jumps for the target heat flux density field in Example 1.

[0077] The method for reconstructing the heat flux density field by scanning electron beam proposed in this embodiment has the following steps:

[0078] S1: Discrete scanning points of target heat flux density field.

[0079] The discrete settings and discrete results of Example 1 are adopted.

[0080] S2: Planning of scanning trajectory, scanning field frequency and electron beam spot radius.

[0081] The scanning path of this embodiment is as follows Figure 17 The two-stage reciprocating raster scan shown in the figure consists of two small scanning cycles forming a large scanning cycle. In each scanning cycle, the electron beam jumps continuously at adjacent scanning points, and the electron beam movement is also continuous between the two small cycles. The scanning field frequency is 100Hz, that is, the electron beam completes 50 large scanning cycles per second, and the electron beam spot radius is set to 2mm.

[0082] S3: Performance calibration of the scan drive system and construction of the ideal current output signal I of the scan drive system t (t) and the actual output current signal I of the scanning drive system r (t) transfer function.

[0083] The scanning drive system, calibration method and results of this embodiment are the same as those of Example 1.

[0084] S4: Establish the energy balance equations of the scanning points and solve them iteratively.

[0085] Based on the discrete unit design of the target heat flux density field in S1 and the scanning trajectory planned in S2, the electron beam scanning trajectory time series is obtained, which is recorded as S t (t). Based on the proportional coefficient between the target deflection distance of the electron beam and the output current signal of the scanning drive system, that is, k = 11A / m, the equation I t (t) = k·S t (t), the ideal current output signal is obtained by conversion. Based on the transfer function established by S3, I t (t) is converted to I r (t), and further combined with the proportional coefficient between the target deflection distance of the electron beam and the output current signal of the scanning drive system, the actual scanning trajectory of the electron beam can be obtained, which is recorded as S r (t). The sequence is divided into 10000 segments at intervals of 1 μs. The average scanning position of the electron beam in the jth time period is recorded as (x j ,y j ). In the j period, the total energy absorbed by the i-th unit is:

[0086]

[0087] The average heat flux absorbed by the i-th unit in a scanning cycle should be equal to the target heat flux, that is:

[0088]

[0089] For the 400 discrete units in step 1, 400 of the above equations can be established and the energy balance equations of the scanning points can be obtained by combining them.

[0090] The iterative solution method of the scanning point energy balance equations is as follows: the initial dwell time is set to be uniformly distributed, the target reconstruction accuracy is 2%, and the dwell time distribution, scanning heat flux density field and reconstruction deviation distribution obtained by iterative solution are respectively as follows: Figures 18-20 shown. Figure 21-23 The reconstruction results of the target heat flux density field using the reconstruction model ignoring the electron beam jumping process under the same reconstruction parameters are given respectively, including the residence time distribution, the scanning heat flux density field and the reconstruction deviation distribution. Figure 20 and Figure 23 By comparison, compared with the reconstruction model that ignores the electron beam jumping process, considering the electron beam jumping process to analyze the target heat flux density field can reduce the maximum absolute value of the reconstruction deviation from 29.80% to 1.98%, and the optimization range is 93.36%.

[0091] Example 3

[0092] This embodiment proposes a system for reconstructing a heat flux density field by scanning an electron beam, comprising:

[0093] Data processing module, used for discretization of target heat flux density field scanning points;

[0094] Scan strategy planning module, used for planning the scanning trajectory, scanning field frequency and electron beam spot radius, where the scanning trajectory connects all scanning points in series;

[0095] Scan drive module, used for performance calibration of the scan drive system and construction of the ideal current output signal I of the scan drive system after pull-type conversion t-s (s) and the actual output current signal I of the scanning drive system r-s Transfer function of (s);

[0096] The dwell time analysis module is used to establish the energy balance equations at the scanning points and perform iterative solutions.

[0097] Example 4

[0098] This embodiment proposes a computer storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for reconstructing a heat flux density field by scanning an electron beam in embodiment 1 or embodiment 2 are implemented.

Claims

1. A method for reconstructing a heat flux density field using a scanning electron beam, characterized in that: The steps are as follows: S1: Discrete scanning points of target heat flux density field; S2: planning of scanning trajectory, scanning field frequency and electron beam spot radius, where the scanning trajectory connects all scanning points in series; S3: Performance calibration of the scan drive system and construction of the ideal current output signal I of the scan drive system after pull-type conversion t-s (s) and the actual output current signal I of the scanning drive system r-s Transfer function of (s); S4: Establish the energy balance equations of the scanning points and solve them iteratively; the specific method is: According to the ratio k of the electron beam’s target deflection distance to the output current signal of the scanning drive system and the transfer function of S3, the real scanning trajectory time series of the electron beam is obtained. The real scanning trajectory time series of the electron beam is divided into n segments at every interval Δt0. The average scanning position of the electron beam in the jth time period is recorded as (x j ,y j ), the spatial position is (x i ,y i )’s target heat flux density for the i-th unit is as follows: Where q″ i is the target heat flux density of the i-th unit; ΔQ ij is the total energy absorbed by the i-th unit; P is the total power of the electron beam absorbed by the sample; R is the electron beam spot radius; ΔL is the scanning point spacing.

2. The method for reconstructing a heat flux density field by scanning an electron beam according to claim 1, characterized in that: The electron beam spot radius is equal to the spacing between discrete scanning points.

3. The method for reconstructing heat flux density field by scanning electron beam according to claim 1, characterized in that: The scanning system in S3 is an open-loop scanning drive system or a second-order or higher-order negative feedback scanning drive system.

4. The method for reconstructing heat flux density field by scanning electron beam according to claim 1, characterized in that: The iterative solution method in S4 is as follows: set the initial residence time to be uniformly distributed, compare the average heat flux density at each scanning point with the target heat flux density, and if the average heat flux density at the scanning point is lower than the target heat flux density, extend the residence time of the scanning point; if the average heat flux density at the scanning point is higher than the target heat flux density, shorten the residence time of the scanning point; when the absolute value of the reconstruction deviation of the average heat flux density at all scanning points is less than the set reconstruction accuracy, the solution of the energy balance equation group of the scanning point is completed.

5. A system for reconstructing heat flux density field by scanning electron beam, characterized in that: include: Data processing module, used for discretization of target heat flux density field scanning points; Scan strategy planning module, used for planning the scanning trajectory, scanning field frequency and electron beam spot radius, where the scanning trajectory connects all scanning points in series; Scan drive module, used for performance calibration of the scan drive system and construction of the ideal current output signal I of the scan drive system after pull-type conversion t-s (s) and the actual output current signal I of the scanning drive system r-s Transfer function of (s); The dwell time analysis module is used to establish the energy balance equations at the scanning points and solve them iteratively. The specific method is as follows: According to the ratio k of the electron beam’s target deflection distance to the output current signal of the scanning drive system and the transfer function of S3, the real scanning trajectory time series of the electron beam is obtained. The real scanning trajectory time series of the electron beam is divided into n segments at every interval Δt0. The average scanning position of the electron beam in the jth time period is recorded as (x j ,y j ), the spatial position is (x i ,y i )’s target heat flux density for the i-th unit is as follows: Where q″ i is the target heat flux density of the i-th unit; ΔQ ij is the total energy absorbed by the i-th unit; P is the total power of the electron beam absorbed by the sample; R is the electron beam spot radius; ΔL is the scanning point spacing.

6. A computer storage medium, characterized in that The computer storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for reconstructing a heat flux density field by a scanning electron beam as described in any one of claims 1 to 4.

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