A method and system for simulation prediction of lightning attachment on fan blades based on magnetohydrodynamics

Abstract

This invention provides a method and system for simulating and predicting lightning attachment on fan blades based on magnetohydrodynamics. The system includes the following steps: S1: constructing a mathematical model of the fan blade and establishing its two-dimensional geometric model; S2: placing a spherical discharge electrode on the two-dimensional fan blade model; S3: assigning electromagnetic and thermal material parameters to the two-dimensional fan blade model and the spherical discharge electrode; S4: applying a lightning current load to the spherical discharge electrode, grounding the central disk area of ​​the two-dimensional fan blade model; S5: encrypting the surface boundary area between the spherical discharge electrode and the fan blade; S6: simulating the lightning attachment process on the fan blade; S7: characterizing the starting position and spatial development trend of the lightning leader and the dynamic evolution of the discharge channel formation; and S8: determining the final lightning attachment location. This invention accurately predicts lightning attachment locations and reveals the lightning attachment mechanism and influencing factors, providing key technical support for lightning protection design and airworthiness compliance verification of aircraft engine fan blades.

Description

Technical Field

[0001] The present invention relates to the technical field of fan blade lightning attachment simulation, and in particular to a fan blade lightning attachment simulation prediction method and system based on magnetohydrodynamics. Background Art

[0002] As the core power unit of aircraft, reducing energy consumption and improving efficiency are key trends in the development of next-generation engines. Open rotor engines, due to their high bypass ratio, low weight, and low fuel consumption, have become a key focus of next-generation propulsion system research. Composite fan blades, with their high specific strength, high specific modulus, fatigue resistance, and designability, are gradually replacing metal blades in aircraft engines. However, aircraft are frequently struck by lightning during flight. The anisotropic properties and low electrical conductivity of composite materials make them highly susceptible to lightning damage. Fan blades cannot be protected with lightning protection like aircraft skins, significantly increasing the risk of lightning damage to composite fan blades. Combined with the new open rotor engine design, which eliminates the nacelle and increases the size of the blades, the probability of lightning strikes on fan blades increases significantly, posing a significant safety hazard. Furthermore, lightning protection of composite structural components is a mandatory airworthiness requirement. Therefore, research on lightning protection for composite fan blades in aircraft engines is crucial for supporting the successful development and airworthiness certification of new aircraft engines in my country.

[0003] Predicting the attachment location of lightning on fan blades and revealing the lightning current attachment mechanism is the first step in conducting lightning protection research on composite fan blades of aircraft engines. However, the current invention of lightning attachment prediction methods has significant limitations.

[0004] Chinese invention patent application number 202411369062.X discloses a method for predicting lightning attachment points on ships. It simulates lightning attachment tests on a scaled model of a ship to statistically calculate the probability of lightning strikes, and then predicts the lightning attachment position of shipboard equipment. Chinese invention patent application number 201210266010.0 and Chinese invention patent application number 202210306664.5 use the finite element method to obtain the surface electric field distribution of the aircraft model based on electrostatic field simulation, and predict the lightning attachment position of the aircraft in different flight postures. Chinese invention patent application number 202411759137.5 discloses a method for predicting lightning attachment of wind turbines. This method calculates the lightning strike distance based on the electrostatic field results, and comprehensively considers the lightning attachment probability under various blade angles and various electrode positions to predict the lightning attachment position of each component of the wind turbine. Chinese invention patent application number 202510147132.5 discloses a method for analyzing the electric field of a wind turbine blade's rotational posture, which predicts the initial attachment position of lightning strikes on blades at different rotational postures.

[0005] All of the aforementioned lightning attachment prediction methods have drawbacks. The lightning attachment test prediction method requires extensive repeated experiments and statistical analysis, resulting in poor economic efficiency and limited accuracy due to the scaled-down model. Current simulation prediction methods in the aviation field focus on the entire aircraft scale, rather than on detailed analysis of key areas susceptible to lightning damage. Furthermore, the fixed electrode assumption fails to simulate the actual air breakdown and leader development process, resulting in inaccurate predictions of the lightning attachment point. Wind turbine blade lightning attachment simulation prediction methods address the issue of fixed electrodes, but are similarly limited to electrostatic field simulation calculations. They predict lightning attachment points using the electric field gradient method, ignoring the dynamic evolution of plasma channels during lightning discharges, resulting in low accuracy in the predicted lightning attachment locations. Summary of the Invention

[0006] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a method and system for simulating and predicting lightning attachment on fan blades based on magnetohydrodynamics.

[0007] The present invention provides a fan blade lightning attachment simulation prediction method based on magnetohydrodynamics, which has the following characteristics and includes the following steps: S1, constructing a mathematical model of a fan blade and importing it into finite element software to establish its two-dimensional geometric model to obtain a two-dimensional fan blade model; S2, setting a spherical discharge electrode for applying a lightning current load directly above the two-dimensional fan blade model; S3, taking the lower half of the spherical discharge electrode for modeling, and assigning corresponding electromagnetic and thermal material parameters to the two-dimensional fan blade model and the spherical discharge electrode; S4, applying a lightning current load on the spherical discharge electrode, and at the same time grounding the central wheel disk area of ​​the two-dimensional fan blade model; S5, using the calculation domain to calculate the lightning current load. The system is divided into fine tetrahedral grids, and the grids are locally encrypted in the surface boundary areas of the spherical discharge electrode and the fan blades; S6, finite element software is used to calculate the lightning attachment model, and the electromagnetic-thermal-fluid behavior is described by coupling the magnetohydrodynamic equations to simulate the lightning attachment process of the fan blades; S7, the simulation calculation is terminated after the loading process of the lightning current load is completed, and the calculation results of the charge distribution, potential distribution and temperature distribution at different times are extracted to characterize the starting position and spatial development trend of the lightning leader and the dynamic evolution process of the discharge channel formation; S8, the current path and current density distribution on the fan blade surface are extracted to analyze and determine the final attachment position of the lightning.

[0008] The fan blade lightning attachment simulation prediction method based on magnetohydrodynamics provided by the present invention may also have the following feature: wherein the diameter of the fan blade in S1 is 400 mm.

[0009] The fan blade lightning attachment simulation prediction method based on magnetohydrodynamics provided by the present invention may also have the following feature: wherein the radius of the spherical discharge electrode in S2 is 20 mm.

[0010] The fan blade lightning attachment simulation prediction method based on magnetohydrodynamics provided by the present invention may also have the following feature: wherein, in S2, the spherical discharge electrode is set 500 mm above the two-dimensional fan blade model.

[0011] The fan blade lightning attachment simulation prediction method based on magnetohydrodynamics provided by the present invention may also have the following features: wherein the electromagnetic and thermal material parameters in S3 include thermal conductivity, electrical conductivity and specific heat capacity, and the two-dimensional fan blade model and the air domain around the spherical discharge electrode are defined as 1000mm*800mm.

[0012] The fan blade lightning attachment simulation prediction method based on magnetohydrodynamics provided by the present invention may also have the following characteristics: wherein the lightning current load in S4 is a D wave with an applied amplitude of 100 kA and a duration of 5.3 μs.

[0013] The fan blade lightning attachment simulation prediction method based on magnetohydrodynamics provided by the present invention may also have the following features: wherein, in S6, the magnetohydrodynamic equations integrate the fluid conservation law and the electromagnetic field control equations, and the lightning attachment process of the fan blade is calculated according to the following formula:

[0014] Plasma must satisfy the law of conservation of mass, and its mathematical expression follows the continuity equation:

[0015] (1)

[0016] Where ρ is density, v is velocity vector, and t is time. This method regards air as an incompressible fluid, that is, the density ρ is constant.

[0017] The motion state of plasma is described by the momentum conservation equation:

[0018] (2)

[0019] Where μ is the dynamic viscosity, P is the pressure, and F L is the external body force,

[0020] The energy conversion process of plasma is characterized by the energy conservation equation:

[0021] (3)

[0022] Where T is temperature, C p is the constant pressure heat capacity, q is the charge, QJ is Joule heat, Q p is the thermodynamic change caused by gas compression / expansion work, Q vd is the volumetric net radiation heat loss,

[0023] The evolution of the electromagnetic field is governed by Maxwell's equations, expressed as:

[0024] Law of conservation of current: (4)

[0025] Gauss's law: (5)

[0026] Generalized Ohm's law: (6)

[0027] Ampere's Law: (7)

[0028] Faraday's Law: (8)

[0029] Magnetic field is non-dispersive: (9)

[0030] Where J is the current density, D is the dielectric constant, σ is the conductivity, E is the electric field intensity, B is the magnetic induction intensity, and H is the magnetic field intensity. The above magnetohydrodynamic equations are solved by multi-field coupling to calculate the key physical field distribution results of the discharge electrode, fan blades, and surrounding air / plasma domain during the lightning strike, including charge density, potential, electric field intensity, current density, temperature, etc.

[0031] The present invention also provides a fan blade lightning attachment simulation prediction system based on magnetohydrodynamics, including: a two-dimensional fan blade model module, which constructs a mathematical model of a fan blade and imports it into finite element software to establish its two-dimensional geometric model to obtain a two-dimensional fan blade model; a lightning current load application module, which sets a spherical discharge electrode for applying lightning current load just above the two-dimensional fan blade model; a spherical discharge electrode modeling module, which takes the lower half of the spherical discharge electrode for modeling and assigns corresponding electromagnetic and thermal material parameters to the two-dimensional fan blade model and the spherical discharge electrode; a grounding module, which applies lightning current load on the spherical discharge electrode and grounds the central disc area of ​​the two-dimensional fan blade model at the same time; a meshing module, which uses fine meshing to divide the calculation domain into two parts. The tetrahedral grid is divided, and the grid of the surface boundary area of ​​the spherical discharge electrode and the fan blade is locally encrypted; the lightning attachment model calculation module uses finite element software to calculate the lightning attachment model, and describes the electromagnetic-thermal-fluid behavior through the coupled solution of the magnetohydrodynamic equations to simulate the lightning attachment process of the fan blade; the calculation result extraction module terminates the simulation calculation after the loading process of the lightning current load is completed, and extracts the calculation results of the charge distribution, potential distribution and temperature distribution at different times to characterize the starting position and spatial development trend of the lightning leader and the dynamic evolution process of the discharge channel formation; the lightning attachment position analysis module extracts the current path and current density distribution on the fan blade surface, and analyzes and determines the final attachment position of the lightning based on this.

[0032] Functions and effects of the invention

[0033] The magnetohydrodynamics-based fan blade lightning attachment simulation prediction method and system involved in the present invention breaks through the limitations of existing technologies, innovatively introduces plasma discharge theory and magnetohydrodynamics theory, establishes an electromagnetic-thermal-fluid multi-physics field coupling calculation model for lightning attachment to fan blades, fully reveals the attachment mechanism of lightning on fan blades, accurately simulates the development of lightning leaders and the evolution of plasma channels, thereby accurately predicting the lightning attachment position and revealing the lightning attachment mechanism and influencing factors, providing key technical support for the lightning protection design and airworthiness compliance verification of aircraft engine fan blades.

[0034] The present invention realizes refined analysis of blade scale in modeling, constructs a dedicated computational model for the key areas of aircraft engine fan blades, and focuses on high-risk areas for lightning strikes through local grid encryption technology. This breaks through the limitation of existing whole-machine scale simulation that cannot finely analyze the local attachment behavior of blades, providing an accurate basis for protection design.

[0035] The present invention introduces a set of magnetohydrodynamic equations to solve the electromagnetic field, heat conduction and fluid motion, fully characterizing the dynamic evolution mechanism of lightning leader development and plasma channel, overcoming the shortcomings of existing electrostatic field simulation and significantly improving the accuracy of lightning attachment position prediction.

[0036] The present invention adopts multi-field coupling modeling in modeling, uniformly representing the electromagnetic parameters, thermodynamic parameters and fluid dynamics parameters of air plasma as functions of temperature. By solving the magnetohydrodynamic equations, the entire process of air breakdown, lightning leader development and plasma channel formation is described, avoiding the errors caused by existing simplified models and making the calculation results closer to the actual situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the lightning attachment process of fan blades in an embodiment of the present invention.

[0038] Figure 2 Graph showing the functional relationship between air parameters and temperature T in an embodiment of the present invention.

[0039] Figure 3 It is a charge density and potential cloud diagram of the lightning leader development in the calculation results in the embodiment of the present invention.

[0040] Figure 4 It is a temperature cloud diagram of the entire lightning strike process in the calculation results in the embodiment of the present invention.

[0041] Figure 5 It is a current density cloud diagram of the entire lightning strike process in the calculation results in the embodiment of the present invention.

[0042] Figure 6 Schematic diagram of the lightning attachment position of a fan blade in the calculation results in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and the accompanying drawings specifically illustrate the fan blade lightning attachment simulation prediction method and system based on magnetohydrodynamics of the present invention.

[0044] The physical essence of lightning discharge lies in the fact that when the applied electric field strength exceeds the critical ionization threshold of air or a high-frequency induced electric field is applied, a neutral gas medium undergoes an electrical breakdown phase transition, transforming from an insulating state to a conductive state. The high voltage and large current generated by the lightning strike cause the air temperature within the discharge channel to rise sharply, leading to the ionization of molecules and atoms, forming a non-equilibrium plasma channel dominated by free electrons and positive ions. The plasma formed by the air breakdown can be considered a magnetic fluid, and therefore this paper uses magnetohydrodynamic equations to describe the entire lightning discharge process.

[0045] Figure 1 Schematic diagram of the lightning attachment process of fan blades in an embodiment of the present invention.

[0046] like Figure 1As shown, the fan blade lightning attachment simulation prediction method based on magnetohydrodynamics in this embodiment includes the following steps.

[0047] S1, construct a mathematical model of a fan blade with a diameter of 400 mm and import it into the finite element software to establish its two-dimensional geometric model to obtain a two-dimensional fan blade model.

[0048] S2, a spherical discharge electrode for applying lightning current load is set 500 mm above the two-dimensional fan blade model, and the radius of the spherical discharge electrode is 20 mm.

[0049] S3, take the lower half of the spherical discharge electrode for modeling, and assign corresponding electromagnetic and thermal material parameters to the two-dimensional fan blade model and the spherical discharge electrode.

[0050] Figure 2 Graph showing the functional relationship between air parameters and temperature T in an embodiment of the present invention.

[0051] The electromagnetic and thermal material parameters include thermal conductivity, electrical conductivity and specific heat capacity. The air domain around the two-dimensional fan blade model and the spherical discharge electrode is defined as 1000mm*800mm. The electromagnetic parameters, thermodynamic parameters and fluid dynamic parameters of the air material are based on the following Figure 2 The temperature function shown is set to characterize its transition to plasma.

[0052] In step S4, a lightning current load is applied to the spherical discharge electrode. According to the lightning test standard "SAE ARP 5416", a D wave with an amplitude of 100 kA and a duration of 5.3 μs is applied. At the same time, the central disk area of ​​the two-dimensional fan blade model is grounded with a potential of 0.

[0053] S5. Since the finite element simulation involves multi-field coupling calculations of the electromagnetic field, heat conduction, and fluid motion of air / plasma, a fine tetrahedral mesh is used to divide the computational domain, and the mesh is locally encrypted in the surface boundary areas of the spherical discharge electrode and fan blades to improve the convergence, stability, and accuracy of the calculation.

[0054] S6, finite element software is used to calculate the lightning attachment model, and the electromagnetic-thermal-fluid behavior is described by coupling the magnetohydrodynamic equations to simulate the lightning attachment process of the fan blade.

[0055] The magnetohydrodynamic equations integrate the fluid conservation laws and the electromagnetic field governing equations. The lightning attachment process on the fan blades is calculated according to the following equation:

[0056] Plasma must satisfy the law of conservation of mass, and its mathematical expression follows the continuity equation:

[0057] (1)

[0058] Where ρ is density, v is velocity vector, and t is time. This method considers air as an incompressible fluid, that is, the density ρ is constant.

[0059] The motion state of plasma is described by the momentum conservation equation:

[0060] (2)

[0061] Where μ is the dynamic viscosity, P is the pressure, and F L is the external body force.

[0062] The energy conversion process of plasma is characterized by the energy conservation equation:

[0063] (3)

[0064] Where T is temperature, C p is the constant pressure heat capacity, q is the charge, Q J is Joule heat, Q p is the thermodynamic change caused by gas compression / expansion work, Q vd is the volumetric net radiation heat loss.

[0065] The evolution of the electromagnetic field is governed by Maxwell's equations, expressed as:

[0066] Law of conservation of current: (4)

[0067] Gauss's law: (5)

[0068] Generalized Ohm's law: (6)

[0069] Ampere's Law: (7)

[0070] Faraday's Law: (8)

[0071] Magnetic field is non-dispersive: (9)

[0072] Where J is the current density, D is the dielectric constant, σ is the conductivity, E is the electric field intensity, B is the magnetic induction intensity, and H is the magnetic field intensity. The above magnetohydrodynamic equations are solved by multi-field coupling to calculate the key physical field distribution results of the discharge electrode, fan blades, and surrounding air / plasma domain during the lightning strike, including charge density, potential, electric field intensity, current density, temperature, etc.

[0073] Figure 3It is a charge density and potential cloud diagram of the lightning leader development in the calculation results in the embodiment of the present invention. Figure 4 It is a temperature cloud diagram of the entire lightning strike process in the calculation results in the embodiment of the present invention.

[0074] S7, such as Figure 3-Figure 4 As shown in the figure, the simulation calculation is terminated after the loading process of the lightning current load is completed, and the calculation results of the charge distribution, potential distribution and temperature distribution at different times are extracted to characterize the starting position and spatial development trend of the lightning leader and the dynamic evolution process of the discharge channel formation.

[0075] Figure 5 It is a current density cloud diagram of the entire lightning strike process in the calculation results in the embodiment of the present invention. Figure 6 Schematic diagram of the lightning attachment position of a fan blade in the calculation results in an embodiment of the present invention.

[0076] S8, such as Figure 5-Figure 6 As shown in the figure, the current path and current density distribution on the fan blade surface are extracted, and the final attachment position of lightning is analyzed and determined based on this, thereby accurately predicting the lightning attachment position and fully revealing the attachment mechanism of lightning on the fan blade.

[0077] The present invention also discloses a fan blade lightning attachment simulation prediction system based on magnetohydrodynamics, comprising:

[0078] The two-dimensional fan blade model module is carried out according to the above step S1 to construct a mathematical model of the fan blade and import it into the finite element software to establish its two-dimensional geometric model to obtain a two-dimensional fan blade model.

[0079] The lightning current load applying module is performed according to the above step S2, and a spherical discharge electrode for applying the lightning current load is set directly above the two-dimensional fan blade model.

[0080] The spherical discharge electrode modeling module is performed according to the above step S3, and the lower half of the spherical discharge electrode is modeled, and corresponding electromagnetic and thermal material parameters are assigned to the two-dimensional fan blade model and the spherical discharge electrode.

[0081] The grounding module performs the above step S4 to apply a lightning current load on the spherical discharge electrode and simultaneously ground the central disk area of ​​the two-dimensional fan blade model.

[0082] The meshing module is performed according to the above step S5, and the calculation domain is divided into fine tetrahedral meshes, and the mesh of the surface boundary area of ​​the spherical discharge electrode and the fan blade is locally encrypted.

[0083] The lightning attachment model calculation module is performed according to the above step S6, using finite element software to calculate the lightning attachment model, and describing the electromagnetic-thermal-fluid behavior by coupling and solving the magnetohydrodynamic equations to simulate the lightning attachment process of the fan blade.

[0084] The calculation result extraction module performs the above step S7, terminates the simulation calculation after the lightning current load is loaded, and extracts the calculation results of the charge distribution, potential distribution and temperature distribution at different times to characterize the starting position and spatial development trend of the lightning leader and the dynamic evolution process of the discharge channel formation.

[0085] The lightning attachment position analysis module performs the above step S8 to extract the current path and current density distribution on the fan blade surface, and analyzes and determines the final attachment position of the lightning based on the current path and current density distribution.

[0086] This method uniformly characterizes the electromagnetic, thermodynamic, and fluid parameters of air plasma as functions of temperature, sets lightning current loads based on simulated lightning test standards, constructs a geometric model of fan blades, and implements mesh refinement in high-risk areas. By simultaneously solving a system of magnetohydrodynamic equations, it achieves electromagnetic, thermal, and fluid multi-field coupling, simulating the entire process of real-world air breakdown, lightning leader development, and plasma discharge channel formation, overcoming the limitations of electrostatic fields. Based on the transient field distribution (current density / temperature / charge density / potential), the lightning leader development process is dynamically tracked, and the blade surface current density is extracted as a basis for determining the lightning attachment location. The proposed magnetohydrodynamic-based lightning attachment simulation and prediction method for fan blades, for the first time, dynamically simulates the entire physical process of lightning attachment to fan blades. This method significantly improves the authenticity of lightning attachment location prediction results, reveals the lightning attachment mechanism and influencing factors, and provides key technical support for lightning protection design and airworthiness compliance verification for aircraft engine fan blades.

[0087] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fan blade lightning attachment simulation prediction method based on magnetohydrodynamics, characterized in that: The steps include: S1, construct a mathematical model of a fan blade and import it into finite element software to establish its two-dimensional geometric model to obtain a two-dimensional fan blade model; S2, arranging a spherical discharge electrode for applying a lightning current load directly above the two-dimensional fan blade model; S3, modeling the lower half of the spherical discharge electrode, and assigning corresponding electromagnetic and thermal material parameters to the two-dimensional fan blade model and the spherical discharge electrode; S4, applying a lightning current load to the spherical discharge electrode and grounding the central disk area of ​​the two-dimensional fan blade model; S5, dividing the computational domain using a fine tetrahedral grid, and locally encrypting the grids in the surface boundary regions of the spherical discharge electrode and the fan blades; S6, using the finite element software to calculate the lightning attachment model, and describing the electromagnetic-thermal-fluid behavior by coupling the magnetohydrodynamic equations to simulate the lightning attachment process of the fan blade; S7, terminating the simulation calculation after the loading process of the lightning current load is completed, and extracting the calculation results of the charge distribution, potential distribution and temperature distribution at different times to characterize the starting position and spatial development trend of the lightning leader and the dynamic evolution process of the discharge channel formation; S8, extracting the current path and current density distribution on the surface of the fan blade, and analyzing and determining the final attachment position of the lightning based on the current path and current density distribution on the surface of the fan blade. In S6, the magnetohydrodynamic equations integrate the fluid conservation law and the electromagnetic field control equations, and the lightning attachment process of the fan blade is calculated according to the following formula: Plasma must satisfy the law of conservation of mass, and its mathematical expression follows the continuity equation: (1) Where ρ is density, v is velocity vector, and t is time. This method regards air as an incompressible fluid, that is, the density ρ is constant. The motion state of plasma is described by the momentum conservation equation: (2) Where μ is the dynamic viscosity, P is the pressure, and F L is the external body force, The energy conversion process of plasma is characterized by the energy conservation equation: (3) Where T is temperature, C p is the constant pressure heat capacity, q is the charge, Q J is Joule heat, Q p is the thermodynamic change caused by gas compression / expansion work, Q vd is the volumetric net radiation heat loss, The evolution of the electromagnetic field is governed by Maxwell's equations, expressed as: Law of conservation of current: (4) Gauss's law: (5) Generalized Ohm's law: (6) Ampere's Law: (7) Faraday's Law: (8) Magnetic field is non-dispersive: (9) Where J is the current density, D is the dielectric constant, σ is the conductivity, E is the electric field intensity, B is the magnetic induction intensity, and H is the magnetic field intensity. By solving the above magnetohydrodynamic equations through multi-field coupling, the key physical field distribution results of the discharge electrode, fan blades, and surrounding air / plasma domain during the lightning strike are calculated, including charge density, potential, electric field intensity, current density, and temperature.

2. The method for fan blade lightning attachment simulation prediction based on magnetohydrodynamics according to claim 1, characterized in that: in, The diameter of the fan blade in S1 is 400 mm.

3. The method for fan blade lightning attachment simulation prediction based on magnetohydrodynamics according to claim 1, characterized in that: in, The radius of the spherical discharge electrode in S2 is 20 mm.

4. The method for fan blade lightning attachment simulation prediction based on magnetohydrodynamics according to claim 1, characterized in that: in, In S2, the spherical discharge electrode is arranged 500 mm above the two-dimensional fan blade model.

5. The method for fan blade lightning attachment simulation prediction based on magnetohydrodynamics according to claim 1, characterized in that: in, The electromagnetic and thermal material parameters in S3 include thermal conductivity, electrical conductivity and specific heat capacity. The air domain around the two-dimensional fan blade model and the spherical discharge electrode is defined as 1000mm*800mm.

6. The method for fan blade lightning attachment simulation prediction based on magnetohydrodynamics according to claim 1, characterized in that: in, The lightning current load in S4 is a D wave with an applied amplitude of 100 kA and a duration of 5.3 μs.

7. A system for fan blade lightning attachment simulation prediction method based on magnetohydrodynamics according to any one of claims 1 to 6, characterized in that: include: 2D fan blade model module, builds a mathematical model of a fan blade and imports it into finite element software to establish its 2D geometric model to obtain a 2D fan blade model; A lightning current load application module is provided with a spherical discharge electrode for applying a lightning current load directly above the two-dimensional fan blade model; a spherical discharge electrode modeling module, which models the lower half of the spherical discharge electrode and assigns corresponding electromagnetic and thermal material parameters to the two-dimensional fan blade model and the spherical discharge electrode; a grounding module for applying a lightning current load on the spherical discharge electrode and simultaneously grounding a central disk area of ​​the two-dimensional fan blade model; A meshing module is used to divide the computational domain into fine tetrahedral meshes, and to locally encrypt the meshes of the surface boundary areas of the spherical discharge electrode and the fan blades; a lightning attachment model calculation module, which uses the finite element software to perform lightning attachment model calculations, and describes electromagnetic-thermal-fluid behavior by coupling and solving a set of magnetohydrodynamic equations to simulate the lightning attachment process of the fan blade; A calculation result extraction module terminates the simulation calculation after the loading process of the lightning current load is completed, and extracts the calculation results of the charge distribution, potential distribution and temperature distribution at different times to characterize the starting position and spatial development trend of the lightning leader and the dynamic evolution process of the discharge channel formation; The lightning attachment position analysis module extracts the current path and current density distribution on the surface of the fan blade, and analyzes and determines the final attachment position of the lightning based on the current path and current density distribution on the surface of the fan blade.

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