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The U.S. Navy is considering the development of electromagnetic railguns for future ships for naval surface-fire support (NSFS) and other missions. To reach long ranges, muzzle velocities in excess of 2000 m/s with projectile flight mass of 16 kg and above are needed. Relatively high firing rates are desired; typically 6-12 rounds per minute, so substantial power demands will be made on the ship. For an electrically driven ship, as in the DD(X) concepts presently being explored by the Navy, an existing electrical infrastructure would be in place that could be modified to recharge the pulsed power supplies for the railgun. This study focused on the railgun, the pulsed power system needed to drive the gun, the power system needed to restore the energy required to match the firing rate, and special ship interfaces. Railgun concepts and sizing for the NSFS mission were undertaken, and research and development issues of importance for the success of a future system were identified. Recommendations for analytical and experimental studies that should be undertaken to further address these issues are provided.Index Terms-Electromagnetic railgun, fire support, kinetic energy, projectile, pulsed power.

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We performed numerical simulations to characterize a conceptual naval railgun and to compute the spatial and temporal energy partitions among the kinetic, thermal, and magnetic energies. A numerical study was then undertaken to assess whether the energy partition, thermal, and kinematic characteristics can be examined through a subscale experiment. It turns out that not all field quantities can be consistently scaled, because the field equations involve both diffusion and wave equations. Three subscale cases-where displacement, velocity, and acceleration profiles were kept the same as the full-scale profiles-were considered. The velocity-matching scaling seems to provide the best case for subscale testing of thermal characteristics of a railgun. The results are expected to provide guidance for thermal management schemes and for suitable subscale tests.

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