Research On Mechanism Of Electrostatic Effect In High-altitude And High-speed Flight

The safe operation of aircraft is the basis for ensuring the development and progress of the aerospace industry.However,during the flight,an aircraft acquires electrostatic charges for various reasons such as skin friction with ice crystals,combustion of engine fuel,etc.When electrostatic charges accumulate to a certain extent,and the electric field is greater than or equal to the breakdown threshold field strength of the surrounding medium.Then the electrostatic discharge will occur.Electrostatic discharge is a source of high electric potential on a surface of an aircraft through direct effects.And it can also be coupled into the aircraft through the apertures in the form of radiation.Both of these effects will adversely affect flight safety.Thus,it is vital to gain a good understanding of the research on the charging and discharging mechanism of aircraft in order to quantify electrostatic threats to aircraft and make corresponding electromagnetic protection.This thesis used theoretical analysis and simulation modeling to study the mechanism of the electrostatic effect in high-altitude and high-speed flight.The main research contents and results are as follows:Firstly,this thesis improved the current model of the friction charging between the surface of the aircraft and the ice crystals,based on the characteristics of ice crystals.This model was based on the metal-medium friction mechanism and combined the Poisson potential equation to explain the charge in the ice crystal after friction.The existing experimental data also verified the effectiveness of this improved model.Then,this thesis studied the mechanic of engine jet electrification.This research progress considered the engine as an isolated conductor combined the theory of molecular dynamics,the particle’s Maxwell velocity distribution function,and the principle of mirror image.The result showed that when the engine is regarded as an isolated conductor,its surface can reach a stable negative potential of-0.1624 V within 0.2ns.Secondly,this thesis also studied the mechanism of corona discharge at the tip of the aircraft tail and the partial discharge of the aircraft body and obtained the threshold voltage of the discharge.In addition,according to the charging and discharging mechanism of the aircraft,we studied the surface charge distribution of the aircraft and calculated the self-capacitance value combined with Q3 D electromagnetic simulation software.Then,we also analyzed the factors that affect the maximum electrostatic potential during electrostatic balance.Finally,this thesis established an aircraft model in the electromagnetic simulation software and studied the electromagnetic field distribution inside and outside the aircraft shell during corona discharge.The corona discharge current was injected into the aircraft’s empennage to analyze the influence of corona discharge on the signal transmission quality of the cables in the aircraft under the condition of changes in the line type,length,position of the cable,and the integrity of the aircraft casing.The purpose of this was to provide a theoretical basis for the study of aircraft electrostatic protection.