Research on momentum transfer in simple railgun

In this paper, the momentum conservation equation in the longitudinal direction for simple railgun was deduced. Then, a three-dimensional model was established and the finite element method was utilized to simulate the problem. Based on the simulation, some results such as the surface force on the electromagnetic field, the electromagnetic force on the conductor in the longitudinal direction were obtained. Besides, the surface force density on different longitudinal section of railgun was analyzed and discussed in details. The results showed that the momentum of the railgun system was conserved when the surface force of the electromagnetic field was contained. Moreover, large amount of longitudinal force was transmitted to the breech by the electromagnetic field in the form of surface force. The exact position and distribution of recoil were related to the current input device.