Plasma discharge characteristics of segmented diverter strips subject to lightning strike

Abstract

In order to research segmented diverters for aircraft lightning protection, a transient 2D multiphysics model based on magnetohydrodynamics theory is proposed to predict the location of the arc plasma discharge and lightning channel, and to simulate the electrothermal behavior. Based on numerical calculation and preliminary analysis, factors that affect the breakdown voltage of the segmented diverter are discussed. The results show that the voltage increase rate of the voltage source, the width of the air gap between metal segments and the geometry of these segments influence the breakdown voltage of the strip. High-voltage tests of the segmented diverter are performed to reveal air breakdown of the strip and redirect the lightning current. Experimental and numerical results are compared to verify the correctness of the numerical model. The ionization of the air gap between metal segments and the breakdown voltage of the strip calculated by the model are qualitatively consistent with experimental results. The breakdown voltage of the segmented diverter is far lower than the lightning voltage. When a lightning strike occurs, the segmented diverter can be quickly ionized to form a plasma channel which can guide the lightning current well.

Impact of In Situ Radome Lightning Diverter Strips on Antenna Performance

“…It can be seen that the maximum surface electric field in the case of a diamond segment is twice that for the case of the circular segment and larger than for the case of square segments indicating that the diamond segment shape will have an earlier breakdown. This is in agreement with the 2D analysis of [9] where diamond shaped elements had lower breakdown voltages compared to the square and circular shaped segments. Fig.18 compares the time waveform of the average x-directed surface electric field across the gap between the segments for each of the three diverter geometries.…”

“…Fig.13 shows that the impact of these two types of diverters on the antenna far field characteristic is very similar. In practice segmented diverter strips have separations below 0.5 mm for good lightning protection [9] and this shows that the impact of segmented diverter strips on antenna radiation is not insignificant as stated in [4,10], and will depend upon the geometry detail of diverter strips. a) b) Fig.12.…”

“…These studies show that segmented diverters with larger metallic segments have lower breakdown voltages compared to those with smaller metallic segments but that smaller segments withstand higher current loads better [3]. The shape of the segments also affects the breakdown voltage, with diamond type segments having lower breakdown voltages than circular or square segments [9]. Furthermore, the effectiveness of the protection afforded using segmented diverters decreases significantly with increased length of the segmented strip, with some studies also showing that segmented diverter strips have limited strike capability compared to metallic diverters that have multi-strike capability [3].…”

“…Understanding the physical mechanisms of the lightning current conduction and the impact that segmented diverter geometry has on the breakdown voltage has mainly been A explored using experimental measurements of lightning channels on either flat or realistic radomes [3,4,7]. Full-wave simulation analyses have been applied to simpler 2D models of lightning channel ignition in segmented diverters [8,9] whilst simplified 3D simulation studies have been used to determine the streamer-leader development on radome diverter strips [6] and field distributions at the nose of the aircraft flying in thunderstorms [10]. These studies show that segmented diverters with larger metallic segments have lower breakdown voltages compared to those with smaller metallic segments but that smaller segments withstand higher current loads better [3].…”

A Laboratory Investigation of the Probable Mechanisms of the Action of an Artificial Thunderstorm Cell on Model Aircraft Radomes

“…Existing constructions cannot eliminate risk of damage to the aircraft radome and/or failure of radio navigational equipment located under it as a result of atmospheric electricity. Therefore, in recent years investigations are being conducted to further perfect the lightning protection (including using various lightning diverter types) for aircraft radomes and equipment under them [4][5][6][7][8][9]15,[17][18][19][20][21][22][23].…”