Exergy Analysis of the Electromagnetic Railgun

In this article, the energy conservation equation of a railgun is established by the Poynting theorem. The concept of exergy in thermodynamics is introduced, and the exergy calculation formula of electromagnetic (EM) energy, kinetic energy, and Joule heat as well as the exergy balance equation of the system are obtained. Using the experimental parameters of a medium-caliber railgun, the exergy of magnetic energy stored in the inductor of the system after a launch is calculated by dynamic simulation, and the exergy loss caused by friction and air drag as irreversible factors is obtained. The skin effect caused by time-varying EM field is considered when calculating the heat exergy of Joule heat of rails. Through the transient thermal simulation of the rail by the finite-element software, the temperature field distribution of the rail is obtained. On this basis, the qualitative temperature for calculating the heat exergy is obtained, and the heat exergy stored on the rail after the launch is calculated by the formula. Finally, how to reduce the exergy loss of the railgun is analyzed qualitatively.