Aircraft lightning stroke initial attachment point simulation method

Abstract

The invention provides an aircraft lightning stroke initial attachment point simulation method. The method comprises the steps that connection between first software and second software is established; 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; on the basis of the first electrostatic field value, obtaining surface charges through a Gaussian law and judging whether positive polarity pilot is started or not; obtaining the number of negative charges of the positive polarity pilot according to an electrostatic balance principle; obtaining aircraft potential according to the number of negative charges; setting boundary conditions according to the aircraft potential and calculating a second electrostatic field value; and based on the second electrostatic field value, judging whether the negative polarity pilot starts or not through the Gaussian law, and if so, recording the initial position. According to the method, pilot channel charge distribution is converted into potential boundary conditions, and the problem that a traditional method depends on the geometrical shape and the motion state of an aircraft is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft lightning protection, and particularly to a method for simulating the initial attachment point of aircraft lightning strikes. Background Art

[0002] Lightning, as a natural phenomenon with significant destructiveness, frequently occurs in the atmosphere. With the continuous increase in the global flight density, the threat posed by lightning strikes to the flight safety of aircraft will become increasingly severe.

[0003] Currently, the confirmation of the initial attachment point of aircraft lightning strikes is generally achieved using empirical formulas or the rolling sphere method. Empirical formulas are usually applicable to aircraft with similar geometric shapes, and when the geometric dimensions change, this method is no longer applicable; the rolling sphere method is based on the electrogeometric model, but in actual processes, the motion state of the aircraft is complex. For example, when the aircraft is climbing or diving, this method is no longer accurate. Therefore, it is very necessary to design a method for simulating the initial attachment point of aircraft lightning strikes. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for simulating the initial attachment point of aircraft lightning strikes. Through the combined simulation of Comsol - MATLAB, the charge distribution of the leader channel is converted into a potential boundary condition to solve the problem of dependence on the geometric shape and motion state of the aircraft in traditional methods.

[0005] To achieve the above purpose, the present invention provides the following solution:

[0006] A method for simulating the initial attachment point of aircraft lightning strikes, comprising the following steps:

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

[0008] Preset an initial simulation environment in the first software, calculate the first electrostatic field value of the initial simulation environment, and transmit the first electrostatic field value to the second software;

[0009] Based on the first electrostatic field value in the second software, calculate the surface charge through Gauss's law, and determine whether to start the positive leader according to the comparison result between the surface charge and the starting threshold;

[0010] Obtain the negative charge quantity of the positive leader according to the principle of electrostatic equilibrium;

[0011] Calculate the aircraft potential according to the negative charge quantity;

[0012] Based on the first software, set the boundary condition according to the aircraft potential and calculate the second electrostatic field value;

[0013] Based on the second electrostatic field value, determine whether the negative leader starts through Gauss's law. If the negative leader starts, record the starting position of the negative leader.

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

[0015] Optionally, presetting the initial simulation environment in the first software specifically includes: determining the size of the simulation domain according to the size of the aircraft model, setting the potential boundary condition on the upper electrode plate in the simulation domain, and setting the grounding boundary condition on the lower electrode plate in the simulation domain.

[0016] Optionally, based on the potential initial attachment point of the aircraft, calculate the first electrostatic field value through the mphinterp function.

[0017] Optionally, the calculation formula for the surface charge is: Q cr = ∫∫ε0E·ds; where Q cr is the electric charge amount at the potential initial attachment point of the aircraft, ε0 is the vacuum permittivity, and E is the surface field strength.

[0018] Optionally, the integration 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.

[0019] Optionally, the calculation formula for the negative charge quantity is: where Q(t) is the negative charge quantity, 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 calculation formula for the aircraft potential is: where is the aircraft potential and C is the self-capacitance.

[0021] Optionally, the integration region of the negative leader is the region where the electric field strength at the potential initial attachment point is greater than the negative corona electric field strength.

[0022] According to the specific embodiments provided by the present invention, the following technical effects are disclosed: The aircraft lightning strike initial attachment point simulation method 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; based on the first electrostatic field value in the second software, calculating surface charges through Gauss's law, and judging whether to start a positive leader according to the comparison result between the surface charges and a starting threshold; obtaining the number of negative charges of the positive leader according to the principle of electrostatic equilibrium; calculating the aircraft electric potential according to the number of negative charges; based on the first software, setting boundary conditions according to the aircraft electric potential, and calculating a second electrostatic field value; based on the second electrostatic field value, judging whether a negative leader starts through Gauss's law. If the negative leader starts, record the starting position of the negative leader. This method solves the problem of dependence on the aircraft geometry and motion state in traditional methods by using the powerful electrostatic calculation ability and boundary condition setting of Comsol software for the complex electric field simulation and complex modeling of the leader channel that need to be carried out in MATLAB, greatly simplifies the aircraft lightning strike initial attachment point simulation method, reduces the difficulty of numerical simulation and improves the accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a flowchart of the aircraft lightning strike initial attachment point simulation method of the present invention;

[0025] Figure 2 It is a distribution diagram of potential initial attachment points of the aircraft of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0028] As Figure 1 shown, the present invention provides a method for simulating the initial attachment point of aircraft lightning strike, including 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 data is transmitted between them through an interface. The interface code in this embodiment is:

[0031] import com.comsol.model*

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

[0033] Step 200: Preset an initial simulation environment in the first software, calculate the first electrostatic field value of the initial simulation environment, and transmit the first electrostatic field value to the second software;

[0034] Specifically, determine the size of the simulation domain according to the size of the aircraft model, set the potential boundary condition on the upper plate in the simulation domain, set the grounding boundary condition on the lower plate in the simulation domain, and set the rest to zero charge.

[0035] Specifically, as Figure 1 shown in the potential initial attachment point of the aircraft, the first electrostatic field value is calculated through the mphinterp function in Comsol. 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: Based on the first electrostatic field value in the second software, calculate the surface charge through Gauss's law, and judge whether to start the positive leader according to the comparison result of the surface charge and the starting threshold;

[0041] Specifically, the calculation formula for the surface charge is:

[0042] Q cr = ∫∫ε0E·ds;

[0043] Wherein, Q cr is the electric charge quantity at the potential initial attachment point of the aircraft, ε0 is the permittivity of free space, which is 8.85*10 -12 F / m in this embodiment, and E is the surface field strength of the aircraft model.

[0044] Specifically, when Q cr is greater than the starting threshold of 1 μC of the positive leader, the positive leader starts; when Q cr does not exceed the starting threshold of 1 μC of the positive leader, the positive leader does not start, and step 200 is returned to recalculate the electrostatic field value after increasing the environmental field strength, and step 300 is executed based on the recalculated electrostatic field value. The integration 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 number of negative charges of the positive leader according to the principle of electrostatic equilibrium;

[0046] Specifically, the calculation formula for the number of negative charges is:

[0047]

[0048] Wherein, Q(t) is the number of negative charges deposited on the aircraft at the current leader length, Q(0) is the initial carrying charge quantity, λ is the charge quantity carried per unit leader length, and l(t) is the leader development length.

[0049] Step 500: Calculate the aircraft potential according to the number of negative charges;

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

[0051]

[0052] Wherein, 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, set the boundary conditions according to the aircraft potential and calculate the second electrostatic field value;

[0054] Specifically, set the aircraft potential as the potential boundary condition of the simulation environment in step 200 and re-execute the subsequent steps.

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

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

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

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

[0059] 1) By virtue of the powerful electrostatic calculation ability of Comsol software and the setting of boundary conditions, the problem of dependence of traditional methods on the aircraft geometry and motion state is solved;

[0060] 2) This method is based on the physical basis of leader discharge, enhancing the understanding of the phenomenon of aircraft lightning attachment;

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

[0062] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0063] In the present invention, specific examples are used to elaborate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, there will be changes in the specific implementation manner and application scope according to the idea of the present invention. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for simulating the initial attachment point of aircraft lightning strikes, characterized in that, It includes the following steps: Establish a connection between the first software and the second software, and upload the aircraft model to the second software; Preset an initial simulation environment in the first software, calculate the first electrostatic field value of the initial simulation environment, and transmit the first electrostatic field value to the second software; Based on the first electrostatic field value in the second software, calculate the surface charge through Gauss's law, and determine whether to start the positive leader according to the comparison result between the surface charge and the starting threshold; Obtain the number of negative charges of the positive leader according to the principle of electrostatic equilibrium; Calculate the aircraft electric potential according to the number of negative charges; Based on the first software, set boundary conditions according to the aircraft electric potential and calculate the second electrostatic field value; Based on the second electrostatic field value, judge whether the negative leader starts through Gauss's law. If the negative leader starts, record the starting position of the negative leader.

2. The aircraft lightning strike initial attachment point simulation method according to claim 1, wherein, Data is transmitted between the first software and the second software through an interface.

3. The aircraft lightning strike initial attachment point simulation method according to claim 1, characterized in that Presetting the initial simulation environment in the first software specifically means: determining the size of the simulation domain according to the size of the aircraft model, setting the electric potential boundary condition on the upper plate in the simulation domain, and setting the grounding boundary condition on the lower plate in the simulation domain.

4. The method for simulating the initial attachment point of aircraft lightning strike according to claim 1, characterized in that Based on the potential initial attachment point of the aircraft, calculate the first electrostatic field value through the mphinterp function.

5. The method for simulating the initial attachment point of aircraft lightning strikes according to claim 1, characterized in that, The calculation formula for the surface charge is: Q cr = ∫∫ε0E·ds; where Q cr is the electric charge amount at the potential initial attachment point of the aircraft, ε0 is the vacuum permittivity, and E is the surface field strength.

6. The aircraft lightning strike initial attachment point simulation method according to claim 1, wherein, The integration region of the positive leader is the region where the electric field intensity at the potential initial attachment point is greater than the positive corona electric field intensity.

7. The method for simulating the initial attachment point of aircraft lightning strike according to claim 1, characterized in that The calculation formula for the number of negative charges is as follows: where Q(t) is the number of negative charges, 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 aircraft lightning strike according to claim 1, characterized in that, The calculation formula for the aircraft electric potential is as follows: Wherein, is the aircraft electric potential, and C is the self-capacitance.

9. The method for simulating the initial attachment point of aircraft lightning strikes according to claim 1, wherein The integration region of the negative leader is the region where the electric field intensity at the potential initial attachment point is greater than the negative corona electric field intensity.

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