电磁轨道炮锡合金镀层U形电枢仿真与试验

Simulation and Experimentation of U-armature for Tin Alloy Coating of Electromagnetic Railgun

为解决电磁轨道炮电枢/轨道间干摩擦阶段摩擦力过大、发射效率低等问题,提出以锡合金作为电枢/轨道间液态导电涂层,对锡合金改善电磁轨道炮发射性能进行了理论分析与数值仿真计算。仿真结果表明:在电流欧姆热等作用下,锡合金能够比普通铝电枢表面更早熔化并形成液态导电涂层,有效减小电枢/轨道间摩擦力。在20 mm×20 mm方膛轨道炮上开展了普通U形铝电枢与锡合金镀层电枢发射对比试验,结果表明:对比5、20、35、50μm 4种厚度的镀层,以35μm厚镀层对电枢炮口速度提升效果最显著,约为22%;对比5、10、15 MA/m 3种线电流密度条件,其中对电枢速度提升贡献最大的是5 MA/m,最小的是15 MA/m;在典型发射条件下,锡合金镀层电枢较普通铝电枢炮口速度,提升幅度约为13%~22%.

In order to solve the problems of excessive friction and low launching efficiency in the dry friction stage between the armature and the rail of electromagnetic railgun, tin alloy was used as a liquid conductive coating between the armature and the rail, on which the theoretical analysis and numerical simulation calculation of tin alloy to improve the launching performance of electromagnetic railgun were carried out. The simulation results show that the tin alloy can melt and form a liquid conductive coa-tings earlier on the surface of armature than common aluminum armature under the action of current ohmic heat, which can effectively reduce the friction between the armature and the rail. Finally, a comparative experiment of the armature with and without Tin-alloy coating was carried out on the 20 mm×20 mm square-bore railgun to compare the launching of ordinary U-shaped aluminium armature with armature coated with tin alloy. The results show that comparing coatings of thickness of 5, 20, 35 and 50 μm, the effect of 35 μm micron thick coatings on armature muzzle velocity is the most remarkable, about 22%;for the line current density conditions of 5, 10 and 15 MA/m, the greatest contribution to armature velocity is 5MA/m, and the smallest is the 15 MA/m. Under typical launching condition, the muzzle speed of armature with tin alloy coating is bigger than that of common aluminum armature, with the promotion amplitude being about 13%~22%.