Influence of Breech Busbar on the Recoil Force of Railgun Launcher

Abstract

The magnitude, distribution, and source of the recoil force play an important role in the launching precision and structural optimization design of the railgun. The breech busbar directly affects the electromagnetic field distribution of the railgun launcher (including armature, rails, and breech busbars), but the influence of the breech busbar on the recoil force of the launcher has not been considered in the previous studies. In this article, the recoil forces of the railgun launchers are studied by changing the structures of the breech busbars. 3-D finite element models of the launchers with flat-plate, swallow-tail, and disk-shaped busbars are established, respectively, and the busbars are fed through six coaxial cables. In the simulation models, the armatures’ movement directions are the positive direction of $Z$ -axis, and the directions of recoil forces are opposite to the armature movement directions. The electromagnetic forces’ distributions of the launchers are calculated by the numerical calculation method. The calculation results show that the breech busbars directly affect the magnitude and distribution of the recoil forces of the rails and the busbars. The $z$ -direction electromagnetic forces on the rails are opposite to the recoil forces, and they are the largest at the contact positions between the armatures and the rails. The electromagnetic forces of the rails can hinder the recoil of the launchers, and their effects on the recoil forces of the launchers cannot be ignored. The $z$ -direction electromagnetic forces on the busbars are in the same direction as the recoil forces, and the recoil forces of the launchers are mainly provided by the busbars. The ratios of the recoil forces to the armature thrust are 0.65, 0.42, and 0.94 for launchers with flat-plate, swallow-tail, and disk-shaped busbars, respectively. It is necessary to consider the influence of the breech busbar on the recoil force of the railgun launcher.