A Novel Field Scaling Method in Electromagnetic Railguns

To overcome the shortcoming of existing field scaling method in electromagnetic railgun, a novel field scaling method with different materials in different scales was proposed. The scaling method was derived based on the governing equations of physical field and projectile dynamics using similarity theory. The results show that field scaling and projectile velocity matching can be achieved simultaneously under the condition of linearly scaling the railgun geometry by using two different materials of lower electrical conductivity in full-scale and higher electrical conductivity in subscale. And the magnetic permeability, mass density, and volumetric specific heat capacity in two kinds of materials should be approximately equal. Aiming at the practical considerations of the negative correlation between mechanical properties and electrical conductivities in existing metals, the scaling method proved that materials of good mechanical properties but lower electrical conductivities can be used in full-scale large-caliber railguns.