A method for simulating initial attachment points of lightning strikes on an aircraft

Abstract

The application provides a method for simulating initial attachment points of lightning strikes on an airplane, which comprises the following steps: establishing a connection between a first software and a second software; presetting an initial simulation environment in the first software, calculating a first electrostatic field value of the initial simulation environment, and transmitting the first electrostatic field value to the second software; obtaining surface charges based on the first electrostatic field value by Gauss law, and judging whether a positive polarity leader is started; obtaining a negative charge quantity of the positive polarity leader according to the principle of electrostatic equilibrium; obtaining an airplane electric potential according to the negative charge quantity; setting a boundary condition according to the airplane electric potential, and calculating a second electrostatic field value; judging whether a negative polarity leader is started based on the second electrostatic field value by Gauss law, and recording a starting position if the negative polarity leader is started. The method solves the problem of dependence of a traditional method on the geometric shape and motion state of the airplane by converting the charge distribution of the leader channel into the potential boundary condition.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft lightning protection, in particular to a method for simulating an initial attachment point of an aircraft lightning strike. Background Art

[0002] Lightning, a highly destructive natural phenomenon, occurs frequently in the atmosphere. As global flight density continues to increase, the threat posed by lightning strikes to aircraft safety will become increasingly severe.

[0003] Currently, determining the initial attachment point of a lightning strike on an aircraft is typically accomplished using empirical formulas or the rolling ball method. Empirical formulas are typically designed for aircraft with similar geometry, but are no longer applicable when the geometry changes. The rolling ball method, based on an electrical geometry model, is inaccurate in the complex motion of aircraft, such as during a climb or dive. Therefore, a method for simulating the initial attachment point of a lightning strike on an aircraft is crucial. Summary of the Invention

[0004] The purpose of this invention is to provide a method for simulating the initial attachment point of lightning strike on an aircraft. Through Comsol-MATLAB joint simulation, the charge distribution of the leader channel is converted into potential boundary conditions to solve the problem that traditional methods rely on the geometric shape and motion state of the aircraft.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A method for simulating the initial attachment point of a lightning strike on an aircraft comprises the following steps:

[0007] Establishing a connection between the first software and the second software, and uploading the aircraft model to the second software;

[0008] Presetting an initial simulation environment in the first software, calculating a first electrostatic field value of the initial simulation environment, and transmitting the first electrostatic field value to the second software;

[0009] In the second software, based on the first electrostatic field value, the surface charge is calculated by Gauss's law, and whether the positive polarity leader starts is determined according to the comparison result between the surface charge and the starting threshold;

[0010] According to the principle of electrostatic balance, the number of negative charges of the positive polarity leader is obtained;

[0011] The electric potential of the aircraft is calculated based on the amount of negative charge;

[0012] Based on the first software, boundary conditions are set according to the electric potential of the aircraft, and a second electrostatic field value is calculated;

[0013] Based on the second electrostatic field value, it is determined by Gauss's law whether the negative polarity leader starts. If the negative polarity leader starts, the starting position of the negative polarity leader is recorded.

[0014] Optionally, the first software and the second software perform data transmission via an interface.

[0015] Optionally, the initial simulation environment is preset in the first software as follows: the size of the simulation domain is determined according to the size of the aircraft model, a potential boundary condition is set on the upper plate in the simulation domain, and a grounding boundary condition is set on the lower plate in the simulation domain.

[0016] Optionally, based on the potential initial attachment point of the aircraft, the first electrostatic field value is calculated by using the mphinterp function.

[0017] Alternatively, the surface charge is calculated as: Q cr =∫∫ε0E·ds; where Q cr is the charge at the potential initial attachment point of the aircraft, ε0 is the dielectric constant of vacuum, and E is the surface field strength.

[0018] Optionally, the integral region of the positive polarity leader is a region where the electric field strength at the potential initial attachment point is greater than the positive polarity corona electric field strength.

[0019] Alternatively, the amount of negative charge is calculated as: Where Q(t) is the amount of negative charge, Q(0) is the initial charge carried, λ is the charge carried per unit leader length, and l(t) is the leader development length.

[0020] Optionally, the aircraft potential is calculated as: in, is the aircraft potential, and C is the self-capacitance.

[0021] Optionally, the integral region of the negative polarity leader is a region where the electric field intensity at the potential initial attachment point is greater than the negative polarity corona electric field intensity.

[0022] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: the method for simulating the initial attachment point of a lightning strike on an aircraft provided by the present invention includes: establishing a connection between a first software and a second software, and uploading an aircraft model to the second software; presetting an initial simulation environment in the first software, calculating a first electrostatic field value of the initial simulation environment, and transmitting the first electrostatic field value to the second software; in the second software, based on the first electrostatic field value, calculating the surface charge by Gauss's law, and judging whether a positive polarity leader starts based on the comparison result between the surface charge and the starting threshold; obtaining the number of negative charges of the positive polarity leader according to the principle of electrostatic balance; calculating the aircraft potential based on the number of negative charges; based on the first software, setting boundary conditions according to the aircraft potential, and calculating the second electrostatic field value; judging whether a negative polarity leader starts based on the second electrostatic field value by Gauss's law, and if the negative polarity leader starts, recording the starting position of the negative polarity leader. This method requires complex electric field simulation and complex modeling of the pilot channel in MATLAB. Through the powerful electrostatic calculation capabilities and boundary condition settings of Comsol software, it solves the problem of traditional methods' dependence on the aircraft's geometry and motion state, greatly simplifies the simulation method of the initial attachment point of the aircraft lightning strike, reduces the difficulty of numerical simulation and improves accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a flow chart of the method for simulating the initial attachment point of a lightning strike on an aircraft according to the present invention;

[0025] Figure 2 This is a distribution map of potential initial attachment points of the aircraft of the present invention. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 As shown, the present invention provides a method for simulating the initial attachment point of a lightning strike on an aircraft, comprising the following steps:

[0029] Step 100: Establish a connection between the first software and the second software, and upload the aircraft model to the second software;

[0030] Specifically, the first software is Comsol and the second software is MATLAB, and the two softwares transmit data through an interface. The interface code in this embodiment is:

[0031] import com.comsol.model*

[0032] import com.comsol.model.util.

[0033] Step 200: Presetting an initial simulation environment in the first software, calculating a first electrostatic field value of the initial simulation environment, and transmitting the first electrostatic field value to the second software;

[0034] Specifically, the size of the simulation domain is determined according to the size of the aircraft model, a potential boundary condition is set on the upper plate in the simulation domain, a ground boundary condition is set on the lower plate in the simulation domain, and the remaining four sides are set to zero charge.

[0035] Specifically, if Figure 2 The potential initial attachment point of the aircraft shown is calculated by the mphinterp function in Comsol to obtain the first electrostatic field value. The code for obtaining the first electrostatic field value in this embodiment is:

[0036] Ex=mphinterp(model,'es.Ex','coord',coord1);

[0037] Ey=mphinterp(model,'es.Ey','coord',coord1);

[0038] Ez=mphinterp(model,'es.Ez','coord',coord1);

[0039] E=mphinterp(model,'es.normE','coord',coord1);

[0040] Step 300: Calculating the surface charge using Gauss's law based on the first electrostatic field value in the second software, and determining whether to start the positive polarity leader based on a comparison result between the surface charge and the starting threshold;

[0041] Specifically, the surface charge is calculated as:

[0042] Q cr =∫∫ε0E·ds;

[0043] Among them, Q cr is the charge at the potential initial attachment point of the aircraft, and ε0 is the dielectric constant of vacuum, which is 8.85*10 in this embodiment. -12 F / m, E is the surface field strength of the aircraft model.

[0044] Specifically, when Q cr When the positive polarity leader is greater than the starting threshold 1uc, the positive polarity leader begins; when Q cr If the positive leader starting threshold value 1uc is not exceeded, the positive leader is not started, and the process returns to step 200. After increasing the ambient field strength, the electrostatic field value is recalculated, and step 300 is executed based on the recalculated electrostatic field value. The integral region of the positive leader is the region where the electric field strength at the potential initial attachment point is greater than the positive corona electric field strength.

[0045] Step 400: Obtain the amount of negative charges of the positive polarity leader according to the principle of electrostatic balance;

[0046] Specifically, the calculation formula for the amount of negative charge is:

[0047]

[0048] Where Q(t) is the amount of negative charge deposited by the aircraft at the current leader length, Q(0) is the initial carried charge, λ is the charge carried per unit leader length, and l(t) is the leader development length.

[0049] Step 500: Calculate the aircraft potential based on the amount of negative charges;

[0050] Specifically, the calculation formula of the aircraft potential is:

[0051]

[0052] in, is the aircraft potential at the current leader length, and C is the self-capacitance of the aircraft.

[0053] Step 600: Based on the first software, boundary conditions are set according to the aircraft potential, and a second electrostatic field value is calculated;

[0054] Specifically, the aircraft potential is set as the potential boundary condition of the simulation environment in step 200, and subsequent steps are executed again.

[0055] Step 700: Based on the second electrostatic field value, determine whether a negative polarity leader starts by using Gauss's law. If a negative polarity leader starts, record the starting position of the negative polarity leader.

[0056] Specifically, if the second electrostatic field value is greater than the starting threshold value 4uc of the negative polarity leader, the negative polarity leader begins, otherwise the process returns to step 300 to continue the positive polarity leader development and recalculate the second electrostatic field value until the second electrostatic field value is greater than the starting threshold value of the negative polarity leader.

[0057] Specifically, the integral region of the negative polarity leader is the region where the electric field intensity at the potential initial attachment point is greater than the negative polarity corona electric field intensity.

[0058] The beneficial effects of the present invention are as follows:

[0059] 1) Comsol software’s powerful electrostatic calculation capabilities and boundary condition settings solve the traditional method’s dependence on the aircraft’s geometry and motion state;

[0060] 2) This method is based on the physics of leader discharges and enhances our understanding of the phenomenon of lightning attachment to aircraft.

[0061] 3) This method can be applied to aircraft of different shapes, greatly simplifying the simulation method of the initial attachment point of lightning strikes on aircraft, reducing the difficulty of numerical simulation and improving the accuracy.

[0062] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0063] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for simulating the initial attachment point of a lightning strike on an aircraft, characterized in that: The steps include: Establishing a connection between the first software and the second software, and uploading the aircraft model to the second software; Presetting an initial simulation environment in the first software, calculating a first electrostatic field value of the initial simulation environment, and transmitting the first electrostatic field value to the second software; In the second software, based on the first electrostatic field value, a surface charge is calculated by Gauss's law, and a determination is made as to whether a positive polarity leader is initiated based on a comparison result of the surface charge with a starting threshold value; According to the principle of electrostatic balance, the amount of negative charges of the positive polarity leader is obtained; The electric potential of the aircraft is calculated based on the amount of negative charge; Based on the first software, setting boundary conditions according to the aircraft potential and calculating a second electrostatic field value; Based on the second electrostatic field value, it is determined by Gauss's law whether a negative polarity leader has started. If the negative polarity leader has started, the starting position of the negative polarity leader is recorded.

2. The method for simulating the initial attachment point of a lightning strike on an aircraft according to claim 1, characterized in that: The first software and the second software perform data transmission via an interface.

3. The method for simulating the initial attachment point of a lightning strike on an aircraft according to claim 1, characterized in that: The initial simulation environment is preset in the first software as follows: the size of the simulation domain is determined according to the size of the aircraft model, a potential boundary condition is set on the upper plate in the simulation domain, and a grounding boundary condition is set on the lower plate in the simulation domain.

4. The method for simulating the initial attachment point of a lightning strike on an aircraft according to claim 1, wherein: Based on the potential initial attachment point of the aircraft, the first electrostatic field value is calculated using the mphinterp function.

5. The method for simulating the initial attachment point of a lightning strike on an aircraft according to claim 1, characterized in that: The surface charge is calculated as follows: Q cr =∫∫ε0E·ds; where Q cr is the charge at the potential initial attachment point of the aircraft, ε0 is the dielectric constant of vacuum, and E is the surface field strength.

6. The method for simulating the initial attachment point of a lightning strike on an aircraft according to claim 1, characterized in that: The integral region of the positive polarity leader is a region where the electric field intensity at the potential initial attachment point is greater than the positive polarity corona electric field intensity.

7. The method for simulating the initial attachment point of a lightning strike on an aircraft according to claim 1, characterized in that: The calculation formula for the amount of negative charge is: Where Q(t) is the amount of negative charge, Q(0) is the initial charge carried, λ is the charge carried per unit leader length, and l(t) is the leader development length.

8. The method for simulating the initial attachment point of a lightning strike on an aircraft according to claim 1, characterized in that: The calculation formula of the aircraft potential is: in, is the aircraft potential, and C is the self-capacitance.

9. The method for simulating the initial attachment point of a lightning strike on an aircraft according to claim 1, characterized in that: The integral region of the negative polarity leader is a region where the electric field intensity at the potential initial attachment point is greater than the negative polarity corona electric field intensity.

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