Three-Dimensional Rail Cooling Analysis for a Repetitively Fired Railgun

A three-dimensional rail cooling analysis for fabrication and demonstration of a stand-alone, repetitive-fire, compulsator-driven 9 MJ gun system has been performed to assure that the entire rail can be maintained below its thermal limit for multiple shots. The three-dimensional rail thermal model can predict the temperature, pressure, and convective heat transfer coefficient variations of the coolant along the 10 m long copper rail. The 9 MJ projectiles are fired every 20 s for 3 min. Water cooling was used in the model for its high cooling capacity. Single liquid phase heat transfer was assumed in the cooling analysis. For multiple shots, the temperature difference between the rail and the water was enhanced due to accumulated heat in the rail. As a result, the heat removal by water increased from shot to shot. The rail temperature initially increased and finally stabilized after a number of shots