Engine tail flame and body polarization characteristic integrated modeling simulation method and device

Abstract

The invention discloses an engine tail flame and body polarization characteristic integrated modeling simulation method and device, and belongs to the field of polarization characteristic modeling. The method comprises the steps that a surface temperature field and a tail flame flow field of an engine body under a target working condition are obtained, and data mapping is conducted on a preset grid; based on the flow field of the tail flame and the scattering physical property of particles in the tail flame, a Monte Carlo method is used for solving a particle polarization radiation transfer equation, and the polarization characteristic of each grid in a tail flame area is obtained; based on the surface temperature field and the material physical property of the body solid surface, the polarization property of each grid on the body solid surface is obtained by using a multi-parameter surface polarization property calculation method; and based on the preset detection angle and the polarization characteristics of each grid of the body and the tail flame, carrying out shielding relation judgment on all surface elements of each grid so as to obtain a total polarization characteristic. According to the scheme, simulation calculation of the body and tail flame integrated polarization characteristic in the combustion flight process of the engine can be achieved, and the calculation precision of the polarization characteristic is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polarization characteristic modeling, and in particular to a method and device for integrated modeling and simulation of engine tail flame and body polarization characteristics. Background Art

[0002] Engine combustion will produce gas, droplets, solid particles, etc., among which the scattering of solid particles will cause the generation of polarization signals. The engine surface has a certain degree of roughness due to its material, which scatters external energy and also generates polarization signals. The traditional engine polarization characteristic modeling and simulation method only considers the engine body, ignoring the solid particles in the tail flame during the engine combustion flight, which limits the calculation accuracy of the polarization characteristics of the engine during flight to a certain extent.

[0003] Therefore, there is an urgent need for an integrated modeling and simulation method and device for the engine tail flame and body polarization characteristics. Summary of the invention

[0004] The present invention provides an integrated modeling and simulation method and device for the polarization characteristics of the engine tail flame and the body, which can solve the problem that the existing modeling method ignores the polarization signal generated by the solid particles in the engine tail flame, resulting in low calculation accuracy of the polarization characteristics during the engine flight. The technical solution is as follows:

[0005] On the one hand, a method for integrated modeling and simulation of engine tail flame and body polarization characteristics is provided, the method comprising:

[0006] Acquire the surface temperature field and tail flame flow field of the engine body under the target working condition, and map the surface temperature field and tail flame flow field to the preset grids of the engine body and tail flame respectively; the tail flame flow field at least includes particle distribution;

[0007] Based on the tail flame flow field and the scattering properties of particles in the tail flame, the particle polarization radiation transfer equation is solved by using the Monte Carlo method to obtain the polarization characteristics of each grid in the tail flame area;

[0008] Based on the surface temperature field and the material properties of the solid surface of the main body, the polarization characteristics of each grid on the solid surface of the main body are obtained by using a multi-parameter surface polarization characteristic calculation method;

[0009] Based on the preset detection angle and the polarization characteristics of each grid of the body and tail flame, the occlusion relationship of all the face elements of each grid is judged to obtain the overall polarization characteristics.

[0010] On the other hand, a device for integrated modeling and simulation of engine tail flame and body polarization characteristics is provided, the device comprising:

[0011] A mapping unit, used to obtain the surface temperature field and tail flame flow field of the engine body under the target working condition, and map the surface temperature field and tail flame flow field to the preset grids of the engine body and tail flame respectively; the tail flame flow field at least includes particle distribution;

[0012] A tail flame calculation unit is used to solve the particle polarization radiation transmission equation based on the tail flame flow field and the scattering properties of the particles in the tail flame by using the Monte Carlo method to obtain the polarization characteristics of each grid in the tail flame area;

[0013] A body calculation unit, used to obtain the polarization characteristics of each grid on the body solid surface by using a multi-parameter surface polarization characteristic calculation method based on the surface temperature field and the material properties of the body solid surface;

[0014] The coupling unit is used to judge the shielding relationship of all the face elements of each grid based on the preset detection angle and the polarization characteristics of each grid of the body and the tail flame, so as to obtain the overall polarization characteristics.

[0015] On the other hand, a computer device is provided, which includes a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the steps of the above-mentioned method.

[0016] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored in the storage medium, and when the computer program is executed by a processor, the steps of the above-mentioned method are implemented.

[0017] On the other hand, a computer program product is provided, comprising a computer program, wherein the computer program implements the steps of the above method when executed by a processor.

[0018] The technical solution provided by the present invention can at least bring the following beneficial effects:

[0019] Firstly, the grid mapping of the engine body and tail flame is carried out based on the engine surface temperature field and tail flame flow field. Secondly, the polarization characteristics of the engine body and tail flame area are calculated respectively. For the tail flame area, the Monte Carlo method is used to solve the particle polarization radiation transfer equation to obtain the polarization characteristics of the tail flame. For the body area, the multi-parameter surface polarization characteristic calculation method is used to obtain the polarization characteristics of the body area. Finally, the occlusion coupling effect between the grids is calculated based on the detection angle, and the total polarization characteristics of the engine during flight are obtained, which effectively improves the calculation accuracy of the polarization characteristics during engine flight. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a flow chart of an integrated modeling and simulation method for engine tail flame and body polarization characteristics provided by one embodiment of the present invention;

[0022] Figure 2 It is a structural diagram of an integrated modeling and simulation device for engine tail flame and body polarization characteristics provided by one embodiment of the present invention;

[0023] Figure 3 It is a hardware architecture diagram of a computer device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] The specific implementation of the above concept is described below.

[0026] Please refer to Figure 1 The embodiment of the present invention provides an integrated modeling and simulation method for engine tail flame and body polarization characteristics, the method comprising:

[0027] Step 100, obtaining the surface temperature field and tail flame flow field of the engine body under the target working condition, and mapping the surface temperature field and tail flame flow field to the preset grids of the engine body and tail flame respectively; the tail flame flow field at least includes particle distribution;

[0028] Step 102, based on the tail flame flow field and the scattering properties of particles in the tail flame, the particle polarization radiation transfer equation is solved by using the Monte Carlo method to obtain the polarization characteristics of each grid in the tail flame area;

[0029] Step 104, based on the surface temperature field and the material properties of the solid surface of the main body, a multi-parameter surface polarization characteristic calculation method is used to obtain the polarization characteristics of each grid on the solid surface of the main body;

[0030] Step 106 , based on the preset detection angle and the polarization characteristics of each grid of the body and the tail flame, the occlusion relationship of all the face elements of each grid is judged to obtain the overall polarization characteristics.

[0031] The polarization characteristics of the engine mainly come from two parts: the polarization of the engine body and the polarization of solid particles in the tail flame. For the body area, the polarization scattering characteristics caused by the roughness of the solid surface are mainly considered. For the tail flame target, the polarization characteristics caused by the particles generated by combustion are mainly considered. At the same time, the occlusion coupling effect caused by the spatial position relationship is considered. The polarization characteristics of the engine tail flame and the body are calculated, which can solve the simulation calculation of the integrated polarization characteristics of the body and tail flame during the engine combustion flight and improve the calculation accuracy of the polarization characteristics.

[0032] In an embodiment of the present invention, firstly, grid mapping of the engine body and tail flame is performed based on the engine surface temperature field and the tail flame flow field; secondly, polarization characteristics of the engine body and tail flame area are calculated respectively, and the Monte Carlo method is used to solve the particle polarization radiation transmission equation for the tail flame area to obtain the polarization characteristics of the tail flame, and a multi-parameter surface polarization characteristic calculation method is used for the body area to obtain the polarization characteristics of the body area; finally, the occlusion coupling effect between grids is calculated based on the detection angle to obtain the total polarization characteristics during the engine flight process, thereby effectively improving the calculation accuracy of the polarization characteristics during the engine flight process.

[0033] Described below Figure 1 How the various steps are performed.

[0034] For step 100:

[0035] In this embodiment, the surface temperature field and tail flame flow field of the engine body under the target working conditions are obtained. The tail flame flow field includes flow field data such as temperature, density, pressure, and particle distribution. The surface temperature field and the tail flame flow field are interpolated and mapped in combination with the integrated preset grid, so that each grid of the engine body contains surface temperature data, and each grid of the tail flame contains flow field data such as temperature, density, pressure, and particle distribution.

[0036] Regarding step 102:

[0037] In some implementations, step 102 may include S1-S6:

[0038] S1, using a random number method to determine the coordinates of the incident point and the incident direction of the photon, so as to emit a number of photons from the coordinates of the incident point and the incident direction.

[0039] S2, for each photon, execute: track the photon, and whenever the photon enters the next grid, take the shortest distance between the photon and each non-incident surface as the travel distance of the grid, and take the surface corresponding to the shortest distance as the new photon exit surface.

[0040] In steps S1 and S2, it is assumed that the physical parameters in each grid are uniformly distributed. The coordinates of the photon incident point are obtained by random number method as (x0, y0, z0) and the incident direction is (u x0 ,u y0 ,u z0 ).

[0041] S3, using the Lambert-Beer law to determine whether the photon is transmitted in the grid.

[0042] S4: If it is not transmitted, then the tracking of the photon is terminated and the tracking of the next photon is started.

[0043] In steps S3 and S4, the Lambert-Beer law is first used to determine whether the photons in the grid are transmitted:

[0044]

[0045] Among them, k e is the extinction coefficient of the medium particles, σ s is a random number between [0,1], and l is the travel distance.

[0046] If the calculation result satisfies the above condition, the photon is not transmitted, the tracking of the photon ends, and the process returns to S2 to track the next photon. If not, the photon is transmitted, and S5 is executed.

[0047] S5, if it is transmitted, then based on the scattering coefficient and scattering phase function of the particles in the grid, combined with the rejection sampling method, the scattering direction and scattering energy of the photon are calculated, and then the photon is tracked to the next grid until the photon reaches the boundary of the tail flame grid. Then, the tracking of the photon is ended and the tracking of the next photon is carried out.

[0048] In some embodiments, the step of "calculating the scattering direction and scattering energy of the photon based on the scattering coefficient and scattering phase function of the particles in the grid in combination with a rejection sampling method" includes:

[0049] Rotate the Stokes vector of the photon to the scattering plane and calculate the Stokes vector after scattering;

[0050] Determining a scattering phase function of the photon based on the polarization component of the photon, and determining a maximum value of the scattering phase function;

[0051] The rejection sampling method is used to select the scattering angle and the rotation angle to obtain the scattering direction of the photon.

[0052] Specifically, after a photon has traveled a free distance, it will be absorbed or scattered due to the action of the medium particles. For polarized radiation transmission, the Stokes vector of the photon must first be rotated to the scattering plane. The Stokes vector S after scattering is sca It can be expressed by the following formula:

[0053] S sca =R(-γ)M(θ)R(-β)S inc

[0054] Among them, γ is the angle between the incident plane and the scattering plane, β is the rotation angle, that is, the angle between the exit plane and the scattering plane, θ is the scattering angle, M(θ) is the Mueller matrix of the scattering angle, R() is the rotation matrix, S inc is the incident Stokes vector.

[0055] Assuming that the incident photon S0 = [I0, Q0, U0, V0], its scattering phase function is:

[0056] P(θ,β)=M 11 (θ)I0+M 12 (θ)[Q0cos(2β)+U0sin(2β)]

[0057] Find the maximum value of the scattering phase function:

[0058] P(θ,β) max =M 11 (θ)I0+M 12 (θ)[Q0 2 +U0 2 ] 1 / 2

[0059] Where M 11 and M 12 is the Mueller matrix element of the scattering angle, which is related to the particle material and shape, θ is the scattering angle, β is the rotation angle, and I, Q, U, and V are the four polarization components.

[0060] The rejection sampling method is used to select the scattering angle and rotation angle. For the rth combination of scattering angle and rotation angle, if there is R r The light is scattered out of this grid element.

[0061] S6, after completing the tracking of all photons, the photon transmission Stokes vector of each grid in the tail flame area is counted to obtain the polarization characteristics of each grid in the tail flame area.

[0062]

[0063] Where S(θ,β) is the solid angle through which the photon passes. The emitted Stokes vector is the polarization characteristic of the grid, I0 is the incident radiation intensity, θ0 is the initial incident zenith angle, N represents the total number of photons, N Ω Solid angle The number of photons emitted, S ω is the Stokes vector of the ωth photon emitted in this direction, θ is the scattering angle, and β is the rotation angle.

[0064] Regarding step 104:

[0065] In some implementations, step 104 may include B1-B3:

[0066] B1, based on the multi-parameter surface polarization characteristics calculation method, derive the solid surface polarization calculation model.

[0067] B2, based on the material properties of the solid surface of the main body and the solid surface polarization calculation model, determine the polarization characteristic matrix of each grid on the solid surface of the main body.

[0068] Next, the derivation process of step B1 is described.

[0069] The expression for calculating the polarization characteristics of solid surfaces based on the multi-parameter surface polarization characteristics calculation method satisfies:

[0070] F(θ i ,φ i ,θ r ,φ r )=F s (θ i ,φ i ,θ r ,φ r )+F v (θ i ,φ i ,θ r ,φ r )

[0071] Among them, θ i ,φ i ,θ r ,φ r are the zenith angle and azimuth angle of the incident light and reflected light respectively, F s is the specular reflection component, F v is the diffuse reflection component.

[0072] Among them, the specular reflection component F s The following formula can be used for calculation:

[0073]

[0074] Among them, k sis an undetermined parameter related to the solid surface material, D is the grid probability density distribution function, G is the shielding factor between grids, M i,j is the Mueller matrix of the solid surface grid, i&j=(0,1,2,3), i and j are the row number and column number respectively, M i,j The specific value is determined by the material's complex refractive index n, k.

[0075] The grid probability density distribution function D is described by the theoretical Beckman model, as shown below:

[0076]

[0077] Where m is the mean square error of the microplane slope, and α is the angle between the normal of the mesh and the normal of the solid surface.

[0078] The shielding factor function G is calculated by the model proposed by Torrance-Sparrow. The specific formula is as follows:

[0079]

[0080] in:

[0081] cos(α)=(cos(θ i )+cos(θ r )) / 2cos(β)

[0082] cos(2β)=cos(θ i )cos(θ r )+sin(θ i )sin(θ r )cos(Δφ)

[0083] Diffuse reflection component F v It can be expressed by the following formula:

[0084]

[0085] Among them, M v i,j is the depolarization matrix, ρ, k s is a parameter related to the solid surface, β is the rotation angle, Δφ is the relative azimuth, θ i ,φ i ,θ r ,φ r are the zenith angle and azimuth angle of the incident light and reflected light respectively.

[0086] In summary, the solid surface polarization calculation model can be obtained as follows:

[0087]

[0088] In the formula, F i,j (θ i ,φ i ,θ r ,φ r ) is the polarization characteristic matrix of the solid surface grid, θ i ,φ i ,θ r ,φ r are the zenith angle and azimuth angle of the incident light and reflected light, respectively, ρ,k s , m, n, k are the material properties of the solid surface of the main body, m is the mean square error of the grid slope, α is the angle between the normal line of the grid and the normal line of the solid surface of the main body, β is the rotation angle, M i,j is the Mueller matrix of the solid surface grid, i and j are the row and column numbers, M v i,j is the debiasing matrix.

[0089] Therefore, the polarization characteristics of the solid surface grid are given by ρ,k s ,m,n,k are used to determine the five parameters. By bringing them into the solid surface polarization calculation model, the polarization characteristic matrix of the solid surface grid can be obtained.

[0090] B3, based on the polarization characteristic matrix of each grid on the solid surface of the bulk, determine the Stokes vector of each grid on the solid surface.

[0091] The Stokes vector of the solid surface mesh is:

[0092] I(θ i ,φ i ,θ r ,φ r )=F 0,0 (θ i ,φ i ,θ r ,φ r )

[0093] Q(θ i ,φ i ,θ r ,φ r )=F 1,0 (θ i ,φ i ,θ r ,φ r )

[0094] U(θ i ,φ i ,θ r ,φ r )=F 2,0 (θ i ,φ i,θ r ,φ r )

[0095] Where I, Q, and U are three polarization components, and the polarization component V is relatively small, so it is ignored.

[0096] Regarding step 106:

[0097] In some implementations, step 106 may include H1-H8:

[0098] H1, for each face element of each grid of the body and tail flame, execute: based on the dot product result of the unit vector in the reverse direction of the preset detection angle and the unit normal vector of the current face element, determine whether the current face element can be detected.

[0099] In this step, the expression for determining whether the face element i can be detected satisfies:

[0100]

[0101] in, is the unit normal vector of the current face element i, is the unit vector in the opposite direction of the preset detection angle. Then the current face element i can be observed. Then the current surface element i is blocked.

[0102] In the embodiment of the present invention, all meshes are triangular meshes, and the unit normal vector n of the current face element i is i It can be expressed as:

[0103]

[0104] in, is the direction vector from coordinate point 1 to coordinate point 2 of the current face element i, It is the direction vector from coordinate point 2 to coordinate point 3 of the current face element i.

[0105] H2, if the dot product result is less than or equal to 0, the current pixel is blocked, and the next pixel is judged;

[0106] H3, if the dot product result is greater than 0, the current surface element can be detected, and continue to determine whether the current surface element is blocked by other surfaces;

[0107] H4, for each other facet, execute:

[0108] Based on the dot product result of the unit normal vector of the current surface element and the direction vector from the center point of the current surface element to the center point of the other surface element, it is determined whether the other surface element is in the hemispherical space radiated by the current surface element.

[0109] In step H4, when the current plane element i can be detected, it is necessary to determine in turn whether each other plane element j blocks the plane element i, and the expression of radiation in the detection direction satisfies:

[0110]

[0111] in, is the direction vector from the center point of the current face element i to the center point of the other face element j, n i is the unit normal vector of the current face element i.

[0112] like , the other plane element j will not block the current plane element i, that is, step H5 is executed.

[0113] like , the other plane element j may block the current plane element i, and the next step of judgment is required, that is, step H6.

[0114] H5, if the dot product result is less than or equal to 0, the current pixel will not be blocked by the other pixel, and the process returns to determine whether the next other pixel blocks the current pixel;

[0115] H6, if the dot product result is greater than 0, the other face element may block the current face element, and continue to use the preset detection angle as the direction of the straight line, and judge by whether the intersection of the straight line at the center of the current face element and the other face element is inside the other face element. If the intersection is inside the other face element, the current face element is blocked. If the intersection is not inside the other face element, the current face element is not blocked by the other face element.

[0116] In step H6, it is determined whether the expression for determining whether the intersection point P of the straight line passing through the center of the current face element i and the plane where the other face element j is located is located inside the other face element j (a triangular face element when meshing) with the preset detection angle reverse direction unit vector v as the straight line direction satisfies:

[0117] S(A j1 ,A j2 ,P)+S(A j2 ,A j3 ,P)+S(A j3 ,A j1 ,P)>S(A j1 ,A j2 ,A j3 )

[0118] Among them, A j1 is the first point of the other face element j, A j2 is the second point of the other face element j, A j3 is the third point of the other face element j, S(A j1 ,Aj2 ,P) is based on A j1 , A j2 The area of ​​the triangle formed by the three points A and P.

[0119] If S(A j1 ,A j2 ,P)+S(A j2 ,A j3 ,P)+S(A j3 ,A j1 ,P)≤S(A j1 ,A j2 ,A j3 ), it means that the intersection point P is located inside the other facet face j, and facet i is blocked. If S(A j1 ,A j2 ,P)+S(A j2 ,A j3 ,P)+S(A j3 ,A j1 ,P)>S(A j1 ,A j2 ,A j3 ), then point P is outside facet j, and facet i is not blocked by facet j.

[0120] H7, after completing the occlusion relationship judgment of all face elements of all grids, superimpose and output the entire Stokes parameters of the unoccluded face elements at the preset detection angle;

[0121] H8, based on the output of the entire Stokes parameter and polarization degree calculation formula, solve the total polarization degree.

[0122] In step H8, the total polarization degree is solved to satisfy the expression:

[0123]

[0124] Where I, Q, and U are the three polarization components in the entire Stokes parameter.

[0125] Please refer to Figure 2 The embodiment of the present invention provides an integrated modeling and simulation device for engine tail flame and body polarization characteristics, the device comprising:

[0126] A mapping unit 201 is used to obtain the surface temperature field and tail flame flow field of the engine body under the target working condition, and map the surface temperature field and tail flame flow field to the preset grids of the engine body and tail flame respectively; the tail flame flow field at least includes particle distribution;

[0127] The tail flame calculation unit 202 is used to solve the particle polarization radiation transmission equation based on the tail flame flow field and the scattering properties of the particles in the tail flame by using the Monte Carlo method to obtain the polarization characteristics of each grid in the tail flame area;

[0128] The body calculation unit 203 is used to obtain the polarization characteristics of each grid on the body solid surface by using a multi-parameter surface polarization characteristic calculation method based on the surface temperature field and the material properties of the body solid surface;

[0129] The coupling unit 204 is used to determine the shielding relationship of all the face elements of each grid based on the preset detection angle and the polarization characteristics of each grid of the body and the tail flame, so as to obtain the overall polarization characteristics.

[0130] In one embodiment of the present invention, the tail flame calculation unit 202 is used to execute:

[0131] The coordinates of the incident point and the incident direction of the photons are determined by random numbers, so as to emit a number of photons from the coordinates of the incident point and the incident direction;

[0132] For each photon, execute:

[0133] Track the photon. Whenever the photon enters the next grid, take the shortest distance between the photon and each non-incident surface as the travel distance of the grid, and take the surface corresponding to the shortest distance as the new photon exit surface.

[0134] Use the Lambert-Beer law to determine whether the photon is transmitted in the grid;

[0135] If it is not transmitted, the tracking of the photon is terminated and the tracking of the next photon is started;

[0136] If it is transmitted, the scattering direction and scattering energy of the photon are calculated based on the scattering coefficient and scattering phase function of the particles in the grid, combined with the rejection sampling method, and the photon is tracked in the next grid until it reaches the boundary of the tail flame grid. The tracking of the photon is terminated and the tracking of the next photon is carried out;

[0137] After completing the tracking of all photons, the photon transmission Stokes vector of each grid in the tail flame area is counted to obtain the polarization characteristics of each grid in the tail flame area.

[0138] In one embodiment of the present invention, the flame tail calculation unit 202 is used to calculate the scattering direction and scattering energy of the photon based on the scattering coefficient and scattering phase function of the particles in the grid in combination with the rejection sampling method:

[0139] Rotate the Stokes vector of the photon to the scattering plane and calculate the Stokes vector after scattering;

[0140] Determining a scattering phase function of the photon based on the polarization component of the photon, and determining a maximum value of the scattering phase function;

[0141] The rejection sampling method is used to select the scattering angle and the rotation angle to obtain the scattering direction of the photon.

[0142] In one embodiment of the present invention, the ontology computing unit 203 is used to execute:

[0143] Based on the multi-parameter surface polarization characteristic calculation method, the solid surface polarization calculation model is derived;

[0144] Based on the material property parameters of the solid surface of the main body and the solid surface polarization calculation model, the polarization characteristic matrix of each grid on the solid surface of the main body is determined;

[0145] Based on the polarization characteristic matrix of each grid on the solid surface, the Stokes vector of each grid on the solid surface is determined.

[0146] In one embodiment of the present invention, the solid surface polarization calculation model in the body calculation unit 203 is:

[0147]

[0148] In the formula, F i,j (θ i ,φ i ,θ r ,φ r ) is the polarization characteristic matrix of the solid surface grid, θ i ,φ i ,θ r ,φ r are the zenith angle and azimuth angle of the incident light and reflected light, respectively, ρ,k s , m, n, k are the material properties of the solid surface of the main body, m is the mean square error of the grid slope, α is the angle between the normal line of the grid and the normal line of the solid surface of the main body, β is the rotation angle, M i,j is the Mueller matrix of the solid surface grid, i and j are the row and column numbers, M v i,j is the debiasing matrix.

[0149] In one embodiment of the present invention, the coupling unit 204 is used to perform:

[0150] For each face element of each mesh of the body and the tail flame, execute:

[0151] Based on the dot product of the unit vector in the reverse direction of the preset detection angle and the unit normal vector of the current face element, determine whether the current face element can be detected;

[0152] If the dot product result is less than or equal to 0, the current pixel is blocked and the process returns to determine the next pixel.

[0153] If the dot product result is greater than 0, the current surface element can be detected, and the current surface element is further determined to be blocked by other surfaces.

[0154] For each additional facet, execute:

[0155] Based on the dot product result of the unit normal vector of the current plane element and the direction vector from the center point of the current plane element to the center point of the other plane element, determine whether the other plane element is in the hemispherical space radiated by the current plane element;

[0156] If the dot product result is less than or equal to 0, the current pixel will not be blocked by the other pixel, and the process returns to determine whether the next other pixel blocks the current pixel.

[0157] If the dot product result is greater than 0, the other face element may block the current face element, and the preset detection angle reverse unit vector is used as the straight line direction, and the intersection of the straight line from the center of the current face element and the other face element is judged to be inside the other face element. If the intersection is inside the other face element, the current face element is blocked; if the intersection is not inside the other face element, the current face element is not blocked by the other face element;

[0158] After completing the occlusion relationship judgment of all face elements of all grids, the entire Stokes parameters of the unoccluded face elements at the preset detection angle are superimposed and output;

[0159] Based on the output of the entire Stokes parameter and polarization degree calculation formula, the total polarization degree is solved.

[0160] It should be noted that: the integrated modeling and simulation device for engine tail flame and body polarization characteristics provided in the above embodiment is only illustrated by the division of the above functional units. In practical applications, the above functions can be assigned to different functional units as needed, that is, the internal structure of the device can be divided into different functional units to complete all or part of the functions described above. In addition, the above device embodiment and the method embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0161] The embodiment of the present application also provides a computer device, please refer to Figure 3 The computer device includes a processor and a memory, in which at least one instruction, at least one program, a code set or an instruction set is stored, and the at least one instruction, at least one program, a code set or an instruction set is loaded and executed by the processor to implement the integrated modeling and simulation method of the engine tail flame and body polarization characteristics provided by the above-mentioned method embodiments.

[0162] An embodiment of the present application also provides a computer-readable storage medium, on which is stored at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by a processor to implement the integrated modeling and simulation method of the engine tail flame and body polarization characteristics provided by the above-mentioned method embodiments.

[0163] An embodiment of the present application also provides a computer program product, which includes a computer program. A processor of a computer device reads the computer program from a computer-readable storage medium, and the processor executes the computer program, so that the computer device executes the integrated modeling and simulation method of the engine tail flame and body polarization characteristics described in any of the above embodiments.

[0164] For the convenience of description, the above system or device is described by dividing it into various modules or units according to its functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0165] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0166] Finally, it should be noted that, in this article, relational terms such as first, second, third and fourth are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0167] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An integrated modeling and simulation method for engine tail flame and body polarization characteristics, characterized in that: include: Acquire the surface temperature field and tail flame flow field of the engine body under the target working condition, and map the surface temperature field and tail flame flow field to the preset grids of the engine body and tail flame respectively; the tail flame flow field at least includes particle distribution; Based on the tail flame flow field and the scattering properties of particles in the tail flame, the particle polarization radiation transfer equation is solved by using the Monte Carlo method to obtain the polarization characteristics of each grid in the tail flame area; Based on the surface temperature field and the material properties of the solid surface of the main body, the polarization characteristics of each grid on the solid surface of the main body are obtained by using a multi-parameter surface polarization characteristic calculation method; Based on the preset detection angle and the polarization characteristics of each grid of the body and tail flame, the occlusion relationship of all the face elements of each grid is judged to obtain the overall polarization characteristics.

2. The method according to claim 1, characterized in that Based on the tail flame flow field and the scattering properties of particles in the tail flame, the Monte Carlo method is used to solve the particle polarization radiation transmission equation to obtain the polarization characteristics of each grid in the tail flame area, including: The coordinates of the incident point and the incident direction of the photons are determined by random numbers, so as to emit a number of photons from the coordinates of the incident point and the incident direction; For each photon, execute: Track the photon. Whenever the photon enters the next grid, take the shortest distance between the photon and each non-incident surface as the travel distance of the grid, and take the surface corresponding to the shortest distance as the new photon exit surface. Use the Lambert-Beer law to determine whether the photon is transmitted in the grid; If it is not transmitted, the tracking of the photon is terminated and the tracking of the next photon is started; If it is transmitted, the scattering direction and scattering energy of the photon are calculated based on the scattering coefficient and scattering phase function of the particles in the grid, combined with the rejection sampling method, and the photon is tracked in the next grid until it reaches the boundary of the tail flame grid. The tracking of the photon is terminated and the tracking of the next photon is carried out; After completing the tracking of all photons, the photon transmission Stokes vector of each grid in the tail flame area is counted to obtain the polarization characteristics of each grid in the tail flame area.

3. The method according to claim 2, characterized in that The method of calculating the scattering direction and scattering energy of the photon based on the scattering coefficient and scattering phase function of the particles in the grid in combination with the rejection sampling method includes: Rotate the Stokes vector of the photon to the scattering plane and calculate the Stokes vector after scattering; Determining a scattering phase function of the photon based on the polarization component of the photon, and determining a maximum value of the scattering phase function; The rejection sampling method is used to select the scattering angle and the rotation angle to obtain the scattering direction of the photon.

4. The method according to claim 1, characterized in that The method of obtaining the polarization characteristics of each grid on the solid surface of the main body by using a multi-parameter surface polarization characteristic calculation method based on the surface temperature field and the material properties of the solid surface of the main body includes: Based on the multi-parameter surface polarization characteristic calculation method, the solid surface polarization calculation model is derived; Based on the material property parameters of the solid surface of the main body and the solid surface polarization calculation model, the polarization characteristic matrix of each grid on the solid surface of the main body is determined; Based on the polarization characteristic matrix of each grid on the solid surface, the Stokes vector of each grid on the solid surface is determined.

5. The method according to claim 4, characterized in that The solid surface polarization calculation model is: In the formula, F i,j (θ i ,φ i ,θ r ,φ r ) is the polarization characteristic matrix of the solid surface grid, θ i ,φ i ,θ r ,φ r are the zenith angle and azimuth angle of the incident light and reflected light, respectively, ρ,k s , m, n, k are the material properties of the solid surface of the main body, m is the mean square error of the grid slope, α is the angle between the normal line of the grid and the normal line of the solid surface of the main body, β is the rotation angle, M i,j is the Mueller matrix of the solid surface grid, i and j are the row and column numbers, M v i,j is the debiasing matrix.

6. The method according to any one of claims 1 to 5, characterized in that The method of judging the blocking relationship of all facets of each grid based on the preset detection angle and the polarization characteristics of the main body and the tail flame to obtain the overall polarization characteristics includes: For each face element of each mesh of the body and tail flame, execute: Based on the dot product of the unit vector in the reverse direction of the preset detection angle and the unit normal vector of the current face element, determine whether the current face element can be detected; If the dot product result is less than or equal to 0, the current pixel is blocked and the process returns to determine the next pixel. If the dot product result is greater than 0, the current surface element can be detected, and the current surface element is further determined to be blocked by other surfaces. For each additional facet, execute: Based on the dot product result of the unit normal vector of the current plane element and the direction vector from the center point of the current plane element to the center point of the other plane element, determine whether the other plane element is in the hemispherical space radiated by the current plane element; If the dot product result is less than or equal to 0, the current pixel will not be blocked by the other pixel, and the process returns to determine whether the next other pixel blocks the current pixel. If the dot product result is greater than 0, the other face element may block the current face element, and the preset detection angle reverse unit vector is used as the straight line direction, and the intersection of the straight line from the center of the current face element and the other face element is judged to be inside the other face element. If the intersection is inside the other face element, the current face element is blocked; if the intersection is not inside the other face element, the current face element is not blocked by the other face element; After completing the occlusion relationship judgment of all face elements of all grids, the entire Stokes parameters of the unoccluded face elements at the preset detection angle are superimposed and output; Based on the output of the entire Stokes parameter and polarization degree calculation formula, the total polarization degree is solved.

7. An integrated modeling and simulation device for engine tail flame and body polarization characteristics, characterized in that: include: A mapping unit, used to obtain the surface temperature field and tail flame flow field of the engine body under the target working condition, and map the surface temperature field and tail flame flow field to the preset grids of the engine body and tail flame respectively; the tail flame flow field at least includes particle distribution; A tail flame calculation unit is used to solve the particle polarization radiation transmission equation using the Monte Carlo method based on the tail flame flow field and the scattering properties of the particles in the tail flame, so as to obtain the polarization characteristics of each grid in the tail flame area; A body calculation unit, used to obtain the polarization characteristics of each grid on the body solid surface by using a multi-parameter surface polarization characteristic calculation method based on the surface temperature field and the material properties of the body solid surface; The coupling unit is used to judge the shielding relationship of all the face elements of each grid based on the preset detection angle and the polarization characteristics of each grid of the body and the tail flame, so as to obtain the overall polarization characteristics.

8. A computer device, characterized in that: The computer device includes a memory and a processor, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the steps of any one of the methods described in claims 1-6.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in any one of claims 1 to 6 are implemented.

10. A computer program product, characterized in that The method comprises a computer program, wherein when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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