A comparison of co-energy and lorenz force based simulations of rail guns

Rail guns are serious contenders for future naval weapon systems because of their ability to overcome the speed limitations of chemically propelled shells. Muzzle velocities in excess of 2km/s are achievable by rail guns and this provides ranges far in excess of current capability. In addition this speed allows the kinetic energy of around 60 MJ alone to provide the destructive effect. The absence of high energy explosive in the warhead also simplifies ship design by the removal of the need for magazines. However such performance requires, for a 20 kg projectile, very large amounts of stored electrical power, perhaps in excess of 200 MJ, together with an allocation of up to 20 MW steady power generation to sustain a firing rate of 6 rounds per minute. A previous paper used a co-energy analysis to explore the ship integration issues such as heat management and rail stresses arising from the operation of a rail gun. This paper extends the granularity of the physical simulation of the rail gun's operation by using a finite element approach based on Ampere's law of magnetic induction and compares its results to those of the original co-energy analysis.