A method and device for calculating infrared characteristics of two-phase jet flame far-field wake of an engine

Abstract

The present application relates to the technical field of infrared characteristic calculation, in particular to a method and device for calculating infrared characteristics of two-phase jet flame far-field wake of an engine, wherein the method comprises: obtaining two-phase jet flame flow field parameters of the engine, ambient temperature and ambient pressure; calculating a temperature variation curve of an axis of the jet flame flow field based on the jet flame flow field parameters; determining an axial length of the far-field wake; determining a far-field wake region; dividing a grid for the far-field wake region; determining a pressure of the far-field wake region; determining temperature, density and component mass concentration variation curves of an axis of the far-field wake region based on the two-phase jet flame flow field parameters of the engine; respectively calculating along a radial layering to determine temperature, density and component mass concentration distribution of the far-field wake region; and calculating infrared radiation of the far-field wake region based on the temperature, density and component mass concentration distribution and the pressure of the far-field wake region. The present application can accurately and quickly calculate infrared characteristics of the two-phase jet flame far-field wake of the engine for several kilometers.

Description

Technical Field

[0001] The present invention relates to the field of infrared characteristic calculation technology, and in particular to a method, device, electronic device and storage medium for calculating the infrared characteristics of the far-field wake of a two-phase jet flame from an engine. Background Technology

[0002] Infrared radiation detection technology boasts advantages such as strong concealment and anti-interference capabilities, and is widely used in early warning systems. The two-phase exhaust (gas and solid particulate matter) of aircraft engines emits strong infrared radiation signals, which are considered one of the main signal sources for space-based infrared detection and early warning. However, the length of the engine's two-phase exhaust is relatively short, typically only a few meters, and the aircraft moves at high speeds, making target acquisition difficult. Detecting the far-field contrail of the exhaust helps to identify targets even after they have been there for some time.

[0003] The far-field contrail of an engine exhaust can spread over distances of up to kilometers. Due to the long distance, traditional computational fluid dynamics methods are often difficult to use to calculate the far-field contrail of exhausts that are several kilometers long, which makes it difficult to accurately analyze the infrared characteristics of the far-field contrail. Summary of the Invention

[0004] Given the difficulty of using existing computational fluid dynamics methods to calculate the far-field wakes of exhaust plumes that can extend for several kilometers, this invention provides a method, apparatus, electronic device, and storage medium for calculating the infrared characteristics of the far-field wakes of two-phase exhaust plumes from engines.

[0005] In a first aspect, embodiments of the present invention provide a method for calculating the far-field infrared characteristics of a two-phase exhaust plume from an engine, including:

[0006] The engine two-phase jet flow field parameters, ambient temperature, and ambient pressure are obtained; wherein the engine two-phase jet flow field parameters include: the axial length and radial length of the jet flow field, as well as the temperature, density, and component mass concentration distribution of the jet flow field;

[0007] Based on the two-phase jet flow field parameters of the engine, the temperature change curve of the jet flow field axis is calculated.

[0008] Based on the temperature change curve of the jet flow field axis and the ambient temperature, the axial length of the far-field wake is determined.

[0009] The far-field wake region is determined based on the axial length of the far-field wake, the axial length of the jet flow field, and the radial length.

[0010] The determined far-field wake region is divided into grids;

[0011] Based on the ambient pressure, the pressure in the far-field wake region is determined;

[0012] Based on the two-phase jet flow field parameters of the engine, the temperature, density, and component mass concentration variation curves of the axis of the far-field wake region are determined;

[0013] Based on the divided grid, the temperature, density, and component mass concentration distribution of the far-field wake region are determined by calculating in layers along the radial direction.

[0014] The infrared radiation of the far-field wake region is calculated based on the temperature, density, component mass concentration distribution, and pressure of the far-field wake region.

[0015] Optionally, calculating the temperature change curve of the jet flow field axis based on the two-phase jet flow field parameters of the engine includes:

[0016] Based on the temperature distribution of the jet flow field, determine whether there are temperature abrupt change points on the axis of the jet flow field;

[0017] If there is a temperature abrupt change point, then based on the location of the temperature abrupt change point, the axial length of the jet flow field, and the temperature distribution of the jet flow field, the temperature change curve of the jet flow field axis is obtained by polynomial fitting method.

[0018] If there is no temperature abrupt change point, the temperature change curve of the jet flow field axis can be obtained by polynomial fitting based on the axial length of the jet flow field and the temperature distribution of the jet flow field.

[0019] Optionally, dividing the determined far-field wake region into a grid includes:

[0020] Based on the initial grid scale, number of grids, and grid growth rate, the grid is divided along the axial and radial directions respectively, making the grid gradually sparser along the axial direction and gradually sparser along the radial direction.

[0021] Optionally, determining the temperature, density, and component mass concentration variation curves of the far-field wake region axis based on the engine's two-phase jet flow field parameters includes:

[0022] Based on the temperature change curve of the jet flow field axis, the temperature change curve of the far-field wake region axis is determined.

[0023] Based on the two-phase jet flow field parameters of the engine, the gas and solid density variation curves of the jet flow field axis are calculated by fitting method.

[0024] Based on the gas and solid density variation curves along the axis of the jet flow field, the gas and solid density variation curves along the axis of the far-field wake region are determined.

[0025] Based on the two-phase jet flow field parameters of the engine, the mass concentration variation curves of each component along the jet flow field axis are calculated by fitting method.

[0026] Based on the mass concentration variation curves of each component along the axis of the jet flow field, the mass concentration variation curves of each component along the axis of the far-field wake region are determined.

[0027] Optionally, the step of calculating the temperature, density, and component mass concentration distribution of the far-field wake region separately along radial layers includes:

[0028] Based on the engine's two-phase jet flow field parameters, ambient temperature, and the temperature variation curve of the far-field wake region's axis, the temperature distribution of the far-field wake region is calculated; the expression for the temperature T(x,y) of the far-field wake region is:

[0029]

[0030] Where x and y represent coordinate positions, T H The ambient temperature is represented by T(x,0), which represents the temperature change curve along the axis of the far-field wake region. axis-original T(L) represents the axial length of the jet flow field. axis-original ,y) is determined based on the temperature distribution of the jet flow field in the two-phase jet flow field parameters of the engine;

[0031] Based on the engine's two-phase jet flow field parameters, ambient gas density, and the gas density variation curve along the axis of the far-field wake region, the gas density distribution in the far-field wake region is calculated; the gas density ρ in the far-field wake region... gas The expression for (x, y) is:

[0032]

[0033] Where, ρ gas (x,0) represents the gas density variation curve along the axis of the far-field wake region, ρ H ρ represents the density of ambient gases. gas (L axis-original ,y) is determined based on the gas density distribution of the jet flow field in the two-phase jet flow field parameters of the engine;

[0034] Based on the two-phase jet flow field parameters of the engine and the fixed density variation curve of the far-field wake region axis, the solid density distribution of the far-field wake region is calculated; the solid density ρ of the far-field wake region is... solid The expression for (x, y) is:

[0035]

[0036] Where, ρ solid (x,0) represents the solid density variation curve along the axis of the far-field wake region, ρ solid(L axis-original ,y) is determined based on the solid density distribution of the jet flow field in the two-phase jet flow field parameters of the engine;

[0037] Based on the two-phase jet flow field parameters of the engine and the mass concentration variation curves of each component along the axis of the far-field wake region, the mass concentration distribution of each component in the far-field wake region is calculated; the mass concentration c of the m-th component in the far-field wake region is... m The expression for (x, y) is:

[0038]

[0039] Among them, c m (x,0) represents the mass concentration variation curve of the m-th component along the axis of the far-field wake region, c m (L axis-original ,y) is determined based on the mass concentration distribution of the m-th component of the jet flow field in the two-phase jet flow field parameters of the engine.

[0040] Optionally, calculating the infrared radiation of the far-field wake region based on the temperature, density, component mass concentration distribution, and pressure of the far-field wake region includes:

[0041] Based on the temperature, gas density, mass concentration distribution of each gas component, and pressure of the far-field wake region, calculate the gas radiation properties of the far-field wake region.

[0042] Based on the temperature, solid density, mass concentration distribution of each solid component, and pressure of the far-field wake region, calculate the solid radiation properties of the far-field wake region.

[0043] The infrared radiation of the far-field wake region is calculated based on the radiometric properties of the gas and solid in the far-field wake region.

[0044] Optionally, the calculation of gas radiation properties of the far-field wake region based on the temperature, gas density, mass concentration distribution of each gas component, and pressure of the far-field wake region includes:

[0045] Based on the temperature, gas density, mass concentration distribution of each gas component, and pressure of the far-field wake region, and combined with wavenumber, the spectral transmittance, spectral emissivity, and spectral absorbance of the gas in the far-field wake region are calculated using a statistical narrow-band model.

[0046] The calculation of solid radiation properties of the far-field wake region based on temperature, solid density, mass concentration distribution of each solid component, and pressure includes:

[0047] Based on the temperature, solid density, mass concentration distribution of each solid component, and pressure in the far-field wake region, the scattering coefficient of the solid particles is calculated using the Mie scattering model, thereby determining the absorptivity and scattering rate of the solid particles.

[0048] The calculation of the infrared radiation of the far-field wake region based on the radiometric properties of the gas and solid in the far-field wake region includes:

[0049] Based on the radiometric properties of the gas and solid in the far-field wake region, the infrared radiation of the far-field wake region is obtained by solving the infrared radiation transfer equation using the apparent ray method.

[0050] Secondly, embodiments of the present invention also provide a device for calculating the far-field infrared characteristics of a two-phase exhaust plume from an engine, comprising:

[0051] The data acquisition module is used to acquire the engine two-phase jet flow field parameters, ambient temperature, and ambient pressure; wherein the engine two-phase jet flow field parameters include: the axial length and radial length of the jet flow field, as well as the temperature, density, and component mass concentration distribution of the jet flow field;

[0052] The temperature calculation module is used to calculate the temperature change curve of the jet flow field axis based on the two-phase jet flow field parameters of the engine.

[0053] The length calculation module is used to determine the axial length of the far-field wake based on the temperature change curve of the jet flow field axis and the ambient temperature.

[0054] The region determination module is used to determine the far-field wake region based on the axial length of the far-field wake, the axial length of the flame flow field, and the radial length.

[0055] A mesh generation module is used to divide the determined far-field wake region into a mesh;

[0056] A pressure determination module is used to determine the pressure in the far-field wake region based on the ambient pressure.

[0057] The curve determination module is used to determine the temperature, density, and component mass concentration variation curves of the axis of the far-field wake region based on the two-phase jet flow field parameters of the engine.

[0058] The distribution determination module is used to calculate the temperature, density, and component mass concentration distribution of the far-field wake region by performing radial layer-by-layer calculations based on the divided grid.

[0059] The radiation calculation module is used to calculate the infrared radiation of the far-field wake region based on the temperature, density, component mass concentration distribution, and pressure of the far-field wake region.

[0060] Thirdly, embodiments of the present invention also provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method described in any embodiment of this specification.

[0061] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the methods described in any embodiment of this specification.

[0062] This invention provides a method, apparatus, electronic device, and storage medium for calculating the infrared characteristics of the far-field contrail of a two-phase exhaust plume from an engine. The invention is based on exhaust flow field parameters, ensuring the accuracy of the flow characteristics of the far-field contrail and making the calculation results more reliable. It does not use traditional computational fluid dynamics methods, has low computational load, and fast processing speed, and can efficiently solve the calculation problem of far-field flow and radiation characteristics of exhaust plume contrails up to kilometers in length. Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 This is a flowchart of a method for calculating the far-field infrared characteristics of a two-phase jet flame from an engine, provided by an embodiment of the present invention.

[0065] Figure 2 This is a schematic diagram of the jet flow field and the far-field wake of the jet;

[0066] Figure 3 This is a hardware architecture diagram of an electronic device provided in an embodiment of the present invention;

[0067] Figure 4 This is a structural diagram of an infrared characteristic calculation device for the far-field wake of a two-phase jet flame of an engine, provided in an embodiment of the present invention. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0069] As mentioned earlier, the two-phase exhaust plume of an engine is relatively short, typically only a few meters long, and the aircraft moves at high speeds, making target acquisition difficult. Detecting the far-field contrail of the exhaust plume helps to identify the target even after it has passed for some time.

[0070] To utilize the far-field contrail of an engine exhaust plume, accurate analysis of its radiation characteristics is necessary. The far-field contrail of an engine exhaust plume can extend over distances of kilometers. Due to this long distance, traditional computational fluid dynamics methods (such as the finite element method) are often insufficient for calculating far-field contrails that can extend for several kilometers, making it difficult to accurately analyze the infrared characteristics of the far-field contrail.

[0071] In view of this, the present invention provides a method for calculating the wake radiation using jet flow field parameters, so as to accurately and quickly calculate the infrared characteristics of the far-field wake of a two-phase jet from an engine that is several kilometers long.

[0072] The following describes the specific implementation of the above concept.

[0073] Please refer to Figure 1 This invention provides a method for calculating the far-field infrared characteristics of a two-phase exhaust plume from an engine. The method includes:

[0074] Step 100: Obtain the two-phase jet flow field parameters of the engine and the ambient temperature T. H and environmental pressure P H ;

[0075] The two-phase jet flow field parameters of the engine include: the axial length L of the jet flow field. axis-original and radial length R radial-original And the temperature, density, and component mass concentration distribution of the jet flow field; ambient temperature T H and environmental pressure P H It can be determined based on the altitude H of the flame, or it can be determined by measurement;

[0076] Step 102: Calculate the temperature change curve of the jet flow field axis based on the two-phase jet flow field parameters of the engine.

[0077] Based on the temperature distribution of the jet flow field, the temperature variation curve of the jet flow field in the axial direction (i.e. along the axis) can be determined.

[0078] Step 104, based on the temperature change curve of the jet flow field axis and the ambient temperature T H Determine the axial length of the far-field wake;

[0079] Step 106: Determine the far-field wake region based on the axial length of the far-field wake, the axial length of the jet flow field, and the radial length.

[0080] Step 108: Divide the determined far-field wake region into a grid;

[0081] Step 110, based on the ambient pressure P H Determine the pressure in the far-field wake region;

[0082] Step 112: Based on the two-phase jet flow field parameters of the engine, determine the temperature, density, and component mass concentration variation curves of the axis of the far-field wake region;

[0083] Step 114: Based on the divided grid, calculate the temperature, density, and component mass concentration distribution of the far-field wake region in radial layers.

[0084] Step 116: Calculate the infrared radiation of the far-field wake region based on the temperature, density, component mass concentration distribution, and pressure of the far-field wake region.

[0085] The embodiments of the present invention determine the far-field wake region and calculate its infrared radiation characteristics based on the two-phase jet flow field parameters of the engine, ensuring the correctness of the flow characteristics of the far-field wake, with high reliability of the calculation results, low computational load, and fast processing speed, and can efficiently solve the calculation problem of far-field flow and radiation characteristics of jet wakes up to kilometers in length.

[0086] The following description Figure 1 The execution method for each step is shown.

[0087] Regarding step 100, "obtain the two-phase jet flow field parameters of the engine", the two-phase jet flow field parameters of the engine can be determined by finite element simulation calculation or actual measurement.

[0088] Finite element simulation can realize data simulation of the jet flow field. Existing research on jets mainly focuses on the jet flow field parameters, and rarely considers the far-field wake caused by the jet.

[0089] Furthermore, the temperature, density, and component mass concentration distribution of the jet flow field can be obtained using the following methods:

[0090] Based on the axial length L of the jet flow field axis-original Mesh the data and set the number of meshes to N. L The first grid size is S 1,L The first grid corresponds to the starting point of the jet flow field parameters, and the grid growth rate is r. L The preferred range is 0.25 < r L If the value is less than 4, then the i-th grid scale can be represented as S. i,L , Nth L Each grid corresponds to the termination of the jet flow field parameters;

[0091] Interpolation along the axial direction yields the flow field information for each grid, including the temperature T of the i-th grid. i Pressure P i and density ρ i , and the mass concentration of each component in the i-th grid.

[0092] Using the above embodiments, the flow field distribution along the axial direction can be obtained through mesh generation and interpolation.

[0093] Regarding step 102, "calculating the temperature change curve of the jet flow field axis based on the two-phase jet flow field parameters of the engine," it further includes:

[0094] Based on the temperature distribution of the jet flow field, determine whether there are temperature abrupt change points on the axis of the jet flow field;

[0095] If there is a temperature abrupt change point, then based on the location of the temperature abrupt change point, the axial length of the jet flow field, and the temperature distribution of the jet flow field, the temperature change curve of the jet flow field axis is obtained by polynomial fitting method.

[0096] If there is no temperature abrupt change point, the temperature change curve of the jet flow field axis can be obtained by polynomial fitting based on the axial length of the jet flow field and the temperature distribution of the jet flow field.

[0097] Considering that the temperature change trend is first oscillating and then monotonically decreasing, in order to accurately determine the temperature abrupt change point, optionally, in step 102, determining whether there is a temperature abrupt change point on the axis of the flame flow field based on the temperature distribution of the flame flow field includes:

[0098] Based on the axial temperature distribution of the jet flow field determined after meshing, temperature abrupt change points are searched along the opposite direction of the axial direction according to the temperature of each grid. If the temperature increases monotonically along the opposite direction of the axial direction, it is considered that there are no temperature abrupt change points; otherwise, it is considered that there are temperature abrupt change points.

[0099] If a temperature abrupt change point exists, then based on the location of the temperature abrupt change point, the axial length of the jet flow field, and the temperature distribution of the jet flow field, a polynomial fitting method is used to obtain the temperature change curve of the jet flow field axis, including:

[0100] If the temperature of the jet flow field does not decrease monotonically along the axial direction, then based on the location L of the temperature abrupt change point... mutation axial length L of the jet flow field axis-original And the temperature distribution of the jet flow field, taking along the axial direction L mutation +0.25(L axis-original -L mutation L mutation +0.5(L axis-original-L mutation L mutation +0.75(L axis-original -L mutation ) and L axis-original The temperature at each location is denoted as T. 0.25L T 0.5L T 0.75L and T L The result was obtained through polynomial fitting. x n Represented as position on the axis, T n Represented by the axis position x n The corresponding temperature, x n The corresponding 0-point position is adjusted according to the temperature abrupt change point; the above parameters are substituted into the formula to calculate the polynomial fitting coefficients a, b, c and d;

[0101] If no temperature abrupt change point exists, then based on the axial length and temperature distribution of the jet flow field, a polynomial fitting method is used to obtain the temperature change curve of the jet flow field axis, including:

[0102] If the temperature of the jet flow field decreases monotonically along the axial direction, then based on the axial length L of the jet flow field... axis-original The temperature distribution of the jet flow field is taken as 0.25L along the axial direction. axis-original 0.5L axis-original 0.75L axis-original and L axis-original The temperature at each location is denoted as T. 0.25L T 0.5L T 0.75L and T L ; obtained through polynomial fitting x n Represented as position on the axis, T n Represented by the axis position x n The corresponding temperature; substituting the above parameters into the formula, the polynomial fitting coefficients a, b, c, and d are calculated.

[0103] In the obtained two-phase jet flow field parameters of the engine, the temperature of the jet flow field does not necessarily decrease monotonically along the axial direction. That is to say, the starting point of the jet flow field parameters does not necessarily correspond to the maximum temperature. Using the above embodiment, the region where the temperature field decreases monotonically can be fitted, thereby determining the temperature change curve of the jet flow field axis.

[0104] Regarding step 104, "determining the axial length of the far-field wake based on the temperature change curve of the jet flow field axis and the ambient temperature," it further includes:

[0105] The ambient temperature is T. H Substitute into the fitted polynomial Take a very small distance step size ΔL, when [T H -T n (L axis-original +kΔL)][T H -T n (L axis-original If +(k+1)ΔL)]≤0, then the axial length L of the far-field wake is obtained. axisfarfield , The distance step size ΔL can usually be taken as the length of the last grid cell in the original flow field grid.

[0106] Using the above embodiments, it can be determined that the flow field temperature on the axis drops to the ambient temperature T. H The length of the far-field wake is taken as the axial length L. axis-farfield .

[0107] Regarding step 106, "determining the far-field wake region based on the axial length of the far-field wake, the axial length of the jet flow field, and the radial length," it further includes:

[0108] The axial range of the far-field wake region is determined based on the axial length of the far-field wake and the axial length of the jet flow field.

[0109] The radial range of the far-field wake region is determined based on the radial length of the jet flow field.

[0110] like Figure 2 As shown, considering that the far-field wake mainly extends axially and hardly extends radially, the radial length of the far-field wake can be considered equal to the radial length of the jet flow field, i.e., R. radial-farfield =R radial-farfield The far-field wake region can be represented as L axis-original ≤x≤L axis-farfield And 0≤y≤R radial-farfield .

[0111] For step 108, "dividing the determined far-field wake region into a grid", the following is further included:

[0112] Based on the initial grid scale, number of grids, and grid growth rate, the grid is divided along the axial and radial directions respectively, making the grid gradually sparser along the axial direction and gradually sparser along the radial direction.

[0113] As the temperature gradually decreases, the change in the flow field slows down. Therefore, the mesh is gradually thinned along the axial direction. Similarly, the change in the flow field is more obvious closer to the axis of symmetry. When the flow field is close to the axis of symmetry, the mesh is made thinner along the radial direction. This helps to reduce the amount of computation while ensuring the accuracy of the calculation.

[0114] Furthermore, the first grid scale can be set to S1, the number of grids to N, and the grid growth rate to r, preferably within the range of 0.25 < r < 4. Then the i-th grid scale can be expressed as S1. i ,

[0115] Alternatively, the grid can be divided only along the axial direction, while the original flow field grid can be directly used radially.

[0116] Regarding step 110, "based on the environmental pressure P" H "Determine the pressure in the far-field wake region." When the jet reaches the far field, the overall pressure of the flow field can be considered to be approximately equal to the ambient pressure P corresponding to an altitude of H. H Consistent, meaning the pressure in the far-field wake region is equal to the ambient pressure P. H .

[0117] Regarding step 112, "determining the temperature, density, and component mass concentration variation curves of the far-field wake region axis based on the engine's two-phase jet flow field parameters" further includes:

[0118] Based on the temperature change curve of the jet flow field axis, the temperature change curve of the far-field wake region axis is determined.

[0119] Based on the two-phase jet flow field parameters of the engine, the gas and solid density variation curves of the jet flow field axis are calculated by fitting method.

[0120] Based on the gas and solid density variation curves along the axis of the jet flow field, the gas and solid density variation curves along the axis of the far-field wake region are determined.

[0121] Based on the two-phase jet flow field parameters of the engine, the mass concentration variation curves of each component along the jet flow field axis are calculated by fitting method.

[0122] Based on the mass concentration variation curves of each component along the axis of the jet flow field, the mass concentration variation curves of each component along the axis of the far-field wake region are determined.

[0123] Furthermore, the gas density variation curve, solid density variation curve, and mass concentration variation curve of each component along the axis of the jet flow field are calculated using a fitting method. Polynomial fitting can be employed, and the specific process can be found in the aforementioned polynomial fitting method for obtaining the temperature variation curve of the jet flow field axis, which will not be elaborated here. In other embodiments, the gas density variation curve, solid density variation curve, and mass concentration variation curve of each component along the axis of the jet flow field can also be calculated using other fitting methods. By considering the far-field wake region as an extension of the jet flow field, the gas density variation curve, solid density variation curve, and mass concentration variation curve of each component along the axis of the far-field wake region can be determined.

[0124] For fluid properties such as temperature, density, and mass concentration, the radial distribution at any axial position approximately follows a Gaussian distribution. Regarding step 114, utilizing self-modeling, "the temperature, density, and component mass concentration distributions of the far-field wake region are determined by calculating in layers along the radial direction," including:

[0125] Based on the engine's two-phase jet flow field parameters, ambient temperature, and the temperature variation curve of the far-field wake region's axis, the temperature distribution of the far-field wake region is calculated; the expression for the temperature T(x,y) of the far-field wake region is:

[0126]

[0127] Where x and y represent the coordinate positions in the flow field, y = 0 corresponds to the position on the axis, and T H Let T(x,0) represent the ambient temperature, and T(x,0) represent the temperature change curve along the axis of the far-field wake region. This can be achieved by fitting a polynomial. L was obtained axis-original T(L) represents the axial length of the jet flow field. axis-original ,y) is determined based on the temperature distribution of the jet flow field in the two-phase jet flow field parameters of the engine, for example, it can be obtained through corresponding interpolation;

[0128] Based on the engine's two-phase jet flow field parameters, ambient gas density, and the gas density variation curve along the axis of the far-field wake region, the gas density distribution in the far-field wake region is calculated; the gas density ρ in the far-field wake region... gas The expression for (x, y) is:

[0129]

[0130] Where, ρ gas (x,0) represents the gas density variation curve along the axis of the far-field wake region, ρ H This represents the density of ambient gases, corresponding to an altitude H. The density ρ can be determined based on the altitude H. gas (L axis-original ,y) is determined based on the gas density distribution of the jet flow field in the two-phase jet flow field parameters of the engine;

[0131] Based on the two-phase jet flow field parameters of the engine and the fixed density variation curve of the far-field wake region axis, the solid density distribution of the far-field wake region is calculated; the solid (particulate matter) density ρ of the far-field wake region is... solid The expression for (x, y) is:

[0132]

[0133] Where, ρ solid (x,0) represents the solid density variation curve along the axis of the far-field wake region, ρ solid,H The density of the solids in the environment is negligible, i.e., ρ. solid,H =0, that is, ρ solid The expression for (x, y) is:

[0134]

[0135] ρ solid (L axis-original ,y) is determined based on the solid density distribution of the jet flow field in the two-phase jet flow field parameters of the engine; in the far field of the jet, due to the long-term heat exchange between the gas and solid particles, the temperature tends to be constant, that is, the temperature of the solid particles in the whole space T solid (x,y)=T(x,y);

[0136] Based on the two-phase jet flow field parameters of the engine and the mass concentration variation curves of each component along the axis of the far-field wake region, the mass concentration distribution of each component in the far-field wake region is calculated; the mass concentration c of the m-th component in the far-field wake region is... m The expression for (x, y) is:

[0137]

[0138] Among them, c m (x,0) represents the mass concentration variation curve of the m-th component along the axis of the far-field wake region, c m,H c represents the mass concentration of the m-th component in the environment, which is negligible. m,H =0, that is, c m The expression for (x, y) is:

[0139]

[0140] c m (L axis-original ,y) is determined based on the mass concentration distribution of the m-th component of the jet flow field in the two-phase jet flow field parameters of the engine.

[0141] Regarding step 116, "Calculate the infrared radiation of the far-field wake region based on the temperature, density, component mass concentration distribution, and pressure of the far-field wake region," it includes:

[0142] Based on the temperature, gas density, mass concentration distribution of each gas component, and pressure of the far-field wake region, the gas radiation properties of the far-field wake region are calculated; the gas radiation properties may include the gas emissivity, absorptivity, and transmittance.

[0143] Based on the temperature, solid density, mass concentration distribution of each solid component, and pressure of the far-field wake region, the solid radiation properties of the far-field wake region are calculated; the solid radiation properties may include the absorptivity and scattering rate of the solid particles.

[0144] The infrared radiation of the far-field wake region is calculated based on the radiometric properties of the gas and solid in the far-field wake region.

[0145] Further, the calculation of gas radiation properties of the far-field wake region based on the temperature, gas density, mass concentration distribution of each gas component, and pressure of the far-field wake region includes:

[0146] Based on the temperature, gas density, mass concentration distribution of each gas component, and pressure of the far-field wake region, and combined with wavenumber, the spectral transmittance, spectral emissivity, and spectral absorbance of the gas in the far-field wake region are calculated using a statistical narrow-band model.

[0147] Specifically, the spectral transmittance, spectral emissivity, and spectral absorbance of the gas in the far-field wake region are calculated using a statistical narrow-band model, including:

[0148] Based on the temperature T and wavenumber η of the far-field wake region, the corresponding temperature T is obtained by interpolation using the NASA-SP-3080 database. i and corresponding wave number η j The absorption coefficient k ij (η j ,T i ) and spectral line spacing d ij (η j ,T i The wave number is determined by the wavelength; let the wave number be η and the wavelength be λ (in μm). T i η represents the i-th interpolation temperature point. j This represents the j-th interpolation wavenumber point;

[0149] Calculate at wavenumber η and temperature T s Doppler broadening parameter γ of gas component s D,s and collision widening parameter γ C,s The expressions are as follows:

[0150]

[0151]

[0152] Where, γ s,s The parameter represents the effect of gas component s on its own collisional broadening. Other gaseous components in the flame besides gaseous component S The parameter a that influences the collisional broadening of gas component s s,s and Take values ​​of 1 and 0.5 respectively, m s M represents the molecular weight of the gaseous component s. s The mole fraction of gaseous component s. ρ represents the mole fraction of the other gaseous component s, and P represents the gas pressure;

[0153] Calculate Doppler widening α D,s And the fine structure parameter α of collision widening C,s The expressions are as follows:

[0154]

[0155]

[0156] l is the gas thickness, u represents the upper limit of integration, and k s (η,T s ) indicates that at wavenumber η and temperature T s absorption coefficient, d s (η,T s ) represents the wave number η and the temperature T. s spectral line spacing;

[0157] The optical thickness parameter under weak line confinement is expressed as:

[0158]

[0159] Calculate the optical thickness parameter X caused by Doppler broadening. D,s The expression is:

[0160]

[0161] Calculate the optical thickness parameter X caused by collision widening C,s The expression is:

[0162]

[0163] Therefore, the optical thickness parameter caused by the combined effects of Doppler broadening and impact broadening can be expressed as Y. s The expression is:

[0164]

[0165] Therefore, the optical thickness of gas component s is calculated as follows:

[0166]

[0167] The spectral transmittance τ can be calculated based on the optical thickness of the gas component s. s and spectral emissivity ε s They are respectively:

[0168]

[0169] This allows us to determine the spectral absorbance.

[0170] Furthermore, based on the temperature, solid density, mass concentration distribution of each solid component, and pressure of the far-field wake region, the solid radiation properties of the far-field wake region are calculated, including:

[0171] Based on the temperature, solid density, mass concentration distribution of each solid component, and pressure in the far-field wake region, the scattering coefficient of the solid particles is calculated using the Mie scattering model, thereby determining the absorptivity and scattering rate of the solid particles.

[0172] Specifically, the solid particles in the jet can be approximated as spherical particles, and the scattering characteristics of the solid particles are calculated using Mie scattering theory, with the particle absorption factor Q. p,a Scattering factor Q p,s and extinction efficiency factor Q p,e It can be calculated using the following formula:

[0173]

[0174] Where, χ=πD p / λ is a dimension parameter, D p Let λ be the diameter of the solid particle, λ be the wavelength, Re represent taking the real part of the complex number, and a n and b n Both are Mie scattering coefficients, which are composite functions of χ and m, where m is the complex refractive index of the particle, m = n - ik, and n and k can be obtained by looking up a table based on the particle properties (such as Al2O3 or C) and wavenumber.

[0175]

[0176]

[0177] In the formula, the symbol with an apostrophe indicates differentiation with respect to the independent variable, ξ n =ψ n -iη n , ψ n and η n It is a Bessel function and satisfies the following recurrence relation:

[0178] ψ -1 (z)=cosz,ψ0(z)=sinz

[0179] η -1 (z)=-sinz,η0(z)=cosz

[0180] The solid particles in the jet flame belong to a sparse particle swarm, and the solid particles scatter independently. The attenuation, scattering, and absorption coefficients of the particle swarm are the algebraic sum of the attenuation, scattering, and absorption coefficients of individual particles. Calculate the scattering coefficient k of the solid particle at wavenumber η. p,η,s and absorption coefficient k p,η,a The expression is:

[0181]

[0182] Among them, D p,i and N p,i It is the particle diameter and number density, Q p,s,i and Q p,a,i These are the scattering factor and absorption factor of the particles.

[0183] Scattering optical thickness τ of solid particles p,s for:

[0184] τ p,s =k p,η,s L

[0185] The empirical formula for particle scattering is:

[0186]

[0187] in, The absorption optical thickness of the gas component. Here, k(η,T) represents the fine structure parameter of the spectral bands, k(η,T) represents the absorption coefficient at wavenumber η and temperature T, and d(η,T) represents the spectral line spacing at wavenumber η and temperature T. This represents the optical thickness after considering particle scattering, where L is the pressure stroke length.

[0188] The calculation of the infrared radiation of the far-field wake region based on the radiometric properties of the gas and solid in the far-field wake region includes:

[0189] Based on the radiometric properties of the gas and solid in the far-field wake region, the infrared radiation of the far-field wake region is obtained by solving the infrared radiation transfer equation using the apparent ray method.

[0190] Electromagnetic waves propagate through a medium, where they are attenuated by absorption or scattering from atoms, molecules, and macroscopic particles within the medium. The medium's own emitted radiation and multiple scattered radiation, occurring along the propagation direction, further enhance their propagation. This paper aims to quantitatively describe these propagation mechanisms, construct a radiative transport model in the medium, and develop methods for calculating the amount of radiation.

[0191] The change in radiance along the transmission path satisfies the following equation:

[0192]

[0193] In the formula, L v (s) is the emitted radiance, where s represents a segment of the medium path, and k v (s) represents the total extinction coefficient of the medium at position s at frequency v, and its expression is:

[0194]

[0195] In the formula, σ v,i (s) is the single-particle extinction cross section of the i-th component at position s, which is the sum of the absorption cross section and the scattering cross section; η i (s) is the particle number density of the i-th component at position s, and all atoms, molecules and macroscopic particles that play an extinction role at frequency v should be included.

[0196] Radiation emitted by the medium in the transmission direction, as well as radiation that re-enters the transmission direction after being scattered multiple times within the medium, forms a radiation enhancement source. v (s) represents the magnitude of the increase in radiance after transmission of a unit distance at position s. It is a function of the particle number density in the medium and the intrinsic radiative properties of the medium.

[0197] Solving the radiative transfer equation yields an integral solution, namely:

[0198]

[0199] In the formula, τ v (s,s1) is the optical thickness of the medium along the transmission path from s to s1, characterized as:

[0200]

[0201] The greater the optical thickness of the medium, the stronger its ability to attenuate radiation.

[0202] If the medium is in local thermal equilibrium, according to Kirchhoff's laws and Planck's law, the emission source function is the blackbody radiation function, that is:

[0203]

[0204] In the formula, T(s) is the temperature of the thermodynamic system, h is Planck's constant, c is the speed of light, k is Boltzmann's constant, and λ is the wavelength.

[0205] The apparent ray (LOS) method is used to solve the infrared radiative transfer equations for the two phases of the jet. The radiative transfer equation for the nth layer is:

[0206]

[0207] In the formula, I λ (n) is the emitted spectral radiation, I λ (n-1) is the emitted spectral radiation of the (n-1)th layer. That is, the optical thickness that takes into account the scattering of solid particles, I b,λ (n) is the blackbody spectral radiation.

[0208] The total spectral radiation on the rays is expressed as:

[0209]

[0210] In the formula, I λ It is the emitted spectral radiation. It is the incident spectral radiation. It is the total optical thickness from the incident point to the nth layer.

[0211] The above embodiments enable accurate and rapid determination of the infrared characteristics of far-field wakes.

[0212] like Figure 3 , Figure 4 As shown, this embodiment of the invention provides a device for calculating the far-field infrared characteristics of a two-phase exhaust plume from an engine. The device can be implemented through software, hardware, or a combination of both. From a hardware perspective, as... Figure 3 The diagram shown is a hardware architecture diagram of an electronic device for calculating the far-field infrared characteristics of a two-phase exhaust plume from an engine, provided in an embodiment of the present invention. (Except for...) Figure 3 In addition to the processor, memory, network interface, and non-volatile memory shown, the electronic device in the embodiment may also include other hardware, such as a forwarding chip responsible for processing packets. Taking software implementation as an example, such as... Figure 4 As shown, a device in a logical sense is formed by the CPU of its electronic device reading the corresponding computer program from the non-volatile memory into memory and running it. This embodiment provides a calculation device for the far-field infrared characteristics of an engine's two-phase exhaust plume (hereinafter referred to as an infrared characteristic calculation device), comprising:

[0213] The data acquisition module 401 is used to acquire the two-phase jet flow field parameters of the engine, the ambient temperature and the ambient pressure; wherein the two-phase jet flow field parameters of the engine include: the axial length and radial length of the jet flow field, as well as the temperature, density and component mass concentration distribution of the jet flow field.

[0214] Temperature calculation module 402 is used to calculate the temperature change curve of the jet flow field axis based on the two-phase jet flow field parameters of the engine.

[0215] The length calculation module 403 is used to determine the axial length of the far-field wake based on the temperature change curve of the jet flow field axis and the ambient temperature.

[0216] The region determination module 404 is used to determine the far-field wake region based on the axial length of the far-field wake, the axial length of the flame flow field, and the radial length.

[0217] Mesh generation module 405 is used to divide the determined far-field wake region into a mesh;

[0218] Pressure determination module 406 is used to determine the pressure of the far-field wake region based on the ambient pressure.

[0219] The curve determination module 407 is used to determine the temperature, density, and component mass concentration variation curves of the axis of the far-field wake region based on the two-phase jet flow field parameters of the engine.

[0220] The distribution determination module 408 is used to calculate the temperature, density, and component mass concentration distribution of the far-field wake region by performing radial layer-by-layer calculations based on the divided grid.

[0221] The radiation calculation module 409 is used to calculate the infrared radiation of the far-field wake region based on the temperature, density, component mass concentration distribution, and pressure of the far-field wake region.

[0222] In this embodiment of the invention, the data acquisition module 401 can be used to execute step 100 in the above method embodiment, the temperature calculation module 402 can be used to execute step 102 in the above method embodiment, the length calculation module 403 can be used to execute step 104 in the above method embodiment, the region determination module 404 can be used to execute step 106 in the above method embodiment, the mesh generation module 405 can be used to execute step 108 in the above method embodiment, the pressure determination module 406 can be used to execute step 110 in the above method embodiment, the curve determination module 407 can be used to execute step 112 in the above method embodiment, the distribution determination module 408 can be used to execute step 114 in the above method embodiment, and the radiation calculation module can be used to execute step 116 in the above method embodiment.

[0223] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on a calculation device for the far-field infrared characteristics of a two-phase exhaust plume from an engine. In other embodiments of the present invention, a calculation device for the far-field infrared characteristics of a two-phase exhaust plume from an engine may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0224] The information interaction and execution process between the modules in the above-mentioned device are based on the same concept as the method embodiment of the present invention, and the specific details can be found in the description of the method embodiment of the present invention, and will not be repeated here.

[0225] This invention also provides an electronic device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements a method for calculating the far-field infrared characteristics of a two-phase jet flame from an engine, according to any embodiment of this invention.

[0226] This invention also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program causes the processor to perform a method for calculating the far-field infrared characteristics of a two-phase jet flame from an engine, according to any embodiment of this invention.

[0227] Specifically, a system or apparatus equipped with a storage medium may be provided, on which software program code implementing the functions of any of the embodiments described above is stored, and the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium.

[0228] In this case, the program code read from the storage medium can itself implement the function of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of the present invention.

[0229] Examples of storage media used to provide program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0230] Furthermore, it should be clear that not only can the program code read by the computer be executed, but also the operating system or other components operating on the computer can be instructed based on the program code to perform some or all of the actual operations, thereby realizing the function of any of the embodiments described above.

[0231] Furthermore, it is understood that the program code read from the storage medium is written to the memory set in the expansion board inserted into the computer or to the memory set in the expansion module connected to the computer. Then, based on the instructions of the program code, the CPU or other components installed on the expansion board or expansion module execute some and all of the actual operations, thereby realizing the function of any of the above embodiments.

[0232] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0233] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as ROM, RAM, magnetic disk, or optical disk.

[0234] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the far-field infrared characteristics of a two-phase exhaust plume from an engine, characterized in that, include: Acquire the two-phase jet flow field parameters of the engine, ambient temperature, and ambient pressure; The two-phase jet flow field parameters of the engine include: the axial length and radial length of the jet flow field, as well as the temperature, density, and component mass concentration distribution of the jet flow field; Based on the two-phase jet flow field parameters of the engine, the temperature change curve of the jet flow field axis is calculated. Based on the temperature change curve of the jet flow field axis and the ambient temperature, the axial length of the far-field wake is determined. The far-field wake region is determined based on the axial length of the far-field wake, the axial length of the jet flow field, and the radial length. The determined far-field wake region is divided into grids; Based on the ambient pressure, the pressure in the far-field wake region is determined; Based on the two-phase jet flow field parameters of the engine, the temperature, density, and component mass concentration variation curves of the axis of the far-field wake region are determined; Based on the divided grid, the temperature, density, and component mass concentration distribution of the far-field wake region are determined by calculating in layers along the radial direction. The infrared radiation of the far-field wake region is calculated based on the temperature, density, component mass concentration distribution, and pressure of the far-field wake region.

2. The method according to claim 1, characterized in that, The calculation of the temperature change curve of the jet flow field axis based on the two-phase jet flow field parameters of the engine includes: Based on the temperature distribution of the jet flow field, determine whether there are temperature abrupt change points on the axis of the jet flow field; If there is a temperature abrupt change point, then based on the location of the temperature abrupt change point, the axial length of the jet flow field, and the temperature distribution of the jet flow field, the temperature change curve of the jet flow field axis is obtained by polynomial fitting method. If there is no temperature abrupt change point, the temperature change curve of the jet flow field axis can be obtained by polynomial fitting based on the axial length of the jet flow field and the temperature distribution of the jet flow field.

3. The method according to claim 1, characterized in that, The process of dividing the determined far-field wake region into a grid includes: Based on the initial grid scale, number of grids, and grid growth rate, the grid is divided along the axial and radial directions respectively, making the grid gradually sparser along the axial direction and gradually sparser along the radial direction.

4. The method according to claim 1, characterized in that, The determination of the temperature, density, and component mass concentration variation curves along the axis of the far-field wake region based on the two-phase jet flow field parameters of the engine includes: Based on the temperature change curve of the jet flow field axis, the temperature change curve of the far-field wake region axis is determined. Based on the two-phase jet flow field parameters of the engine, the gas and solid density variation curves of the jet flow field axis are calculated by fitting method. Based on the gas and solid density variation curves along the axis of the jet flow field, the gas and solid density variation curves along the axis of the far-field wake region are determined. Based on the two-phase jet flow field parameters of the engine, the mass concentration variation curves of each component along the jet flow field axis are calculated by fitting method. Based on the mass concentration variation curves of each component along the axis of the jet flow field, the mass concentration variation curves of each component along the axis of the far-field wake region are determined.

5. The method according to claim 4, characterized in that, The step of calculating the temperature, density, and component mass concentration distribution of the far-field wake region by radially layering the data includes: Based on the engine's two-phase jet flow field parameters, ambient temperature, and the temperature variation curve of the far-field wake region's axis, the temperature distribution of the far-field wake region is calculated; the expression for the temperature T(x,y) of the far-field wake region is: Where x and y represent coordinate positions, T H The ambient temperature is represented by T(x,0), which represents the temperature change curve along the axis of the far-field wake region. axis-original T(L) represents the axial length of the jet flow field. axis-original ,y) is determined based on the temperature distribution of the jet flow field in the two-phase jet flow field parameters of the engine; Based on the engine's two-phase jet flow field parameters, ambient gas density, and the gas density variation curve along the axis of the far-field wake region, the gas density distribution in the far-field wake region is calculated; the gas density ρ in the far-field wake region... gas The expression for (x, y) is: Where, ρ gas (x,0) represents the gas density variation curve along the axis of the far-field wake region, ρ H ρ represents the density of ambient gases. gas (L axis-original ,y) is determined based on the gas density distribution of the jet flow field in the two-phase jet flow field parameters of the engine; Based on the two-phase jet flow field parameters of the engine and the fixed density variation curve of the axis of the far-field wake region, the solid density distribution of the far-field wake region is calculated; the solid density ρ of the far-field wake region is... solid The expression for (x,y) is: Where, ρ solid (x,0) represents the solid density variation curve along the axis of the far-field wake region, ρ solid (L axis-original ,y) is determined based on the solid density distribution of the jet flow field in the two-phase jet flow field parameters of the engine; Based on the two-phase jet flow field parameters of the engine and the mass concentration variation curves of each component along the axis of the far-field wake region, the mass concentration distribution of each component in the far-field wake region is calculated; the mass concentration c of the m-th component in the far-field wake region is... m The expression for (x, y) is: Among them, c m (x,0) represents the mass concentration variation curve of the m-th component along the axis of the far-field wake region, c m (L axis-original ,y) is determined based on the mass concentration distribution of the m-th component of the jet flow field in the two-phase jet flow field parameters of the engine.

6. The method according to claim 5, characterized in that, The calculation of the infrared radiation of the far-field wake region based on the temperature, density, component mass concentration distribution, and pressure of the far-field wake region includes: Based on the temperature, gas density, mass concentration distribution of each gas component, and pressure of the far-field wake region, calculate the gas radiation properties of the far-field wake region. Based on the temperature, solid density, mass concentration distribution of each solid component, and pressure of the far-field wake region, calculate the solid radiation properties of the far-field wake region. The infrared radiation of the far-field wake region is calculated based on the radiometric properties of the gas and solid in the far-field wake region.

7. The method according to claim 6, characterized in that, The calculation of gas radiation properties in the far-field wake region based on the temperature, gas density, mass concentration distribution of each gas component, and pressure includes: Based on the temperature, gas density, mass concentration distribution of each gas component, and pressure of the far-field wake region, and combined with wavenumber, the spectral transmittance, spectral emissivity, and spectral absorbance of the gas in the far-field wake region are calculated using a statistical narrow-band model. The calculation of solid radiation properties of the far-field wake region based on temperature, solid density, mass concentration distribution of each solid component, and pressure includes: Based on the temperature, solid density, mass concentration distribution of each solid component, and pressure in the far-field wake region, the scattering coefficient of the solid particles is calculated using the Mie scattering model, thereby determining the absorptivity and scattering rate of the solid particles. The calculation of the infrared radiation of the far-field wake region based on the radiometric properties of the gas and solid in the far-field wake region includes: Based on the radiometric properties of the gas and solid in the far-field wake region, the infrared radiation of the far-field wake region is obtained by solving the infrared radiation transfer equation using the apparent ray method.

8. A device for calculating the far-field infrared characteristics of a two-phase jet exhaust from an engine, characterized in that, include: The data acquisition module is used to acquire the two-phase jet flow field parameters, ambient temperature, and ambient pressure of the engine. The two-phase jet flow field parameters of the engine include: the axial length and radial length of the jet flow field, as well as the temperature, density, and component mass concentration distribution of the jet flow field; The temperature calculation module is used to calculate the temperature change curve of the jet flow field axis based on the two-phase jet flow field parameters of the engine. The length calculation module is used to determine the axial length of the far-field wake based on the temperature change curve of the jet flow field axis and the ambient temperature. The region determination module is used to determine the far-field wake region based on the axial length of the far-field wake, the axial length of the flame flow field, and the radial length. A mesh generation module is used to divide the determined far-field wake region into a mesh; A pressure determination module is used to determine the pressure in the far-field wake region based on the ambient pressure. The curve determination module is used to determine the temperature, density, and component mass concentration variation curves of the axis of the far-field wake region based on the two-phase jet flow field parameters of the engine. The distribution determination module is used to calculate the temperature, density, and component mass concentration distribution of the far-field wake region by performing radial layer-by-layer calculations based on the divided grid. The radiation calculation module is used to calculate the infrared radiation of the far-field wake region based on the temperature, density, component mass concentration distribution, and pressure of the far-field wake region.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1-7.

10. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed in the computer, it causes the computer to perform the method of any one of claims 1-7.

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