Modelling of rail gun and study of its pulsed power supply system using computer simulation techniques

Abstract

The rail gun is an electromagnetic apparatus that drives an armature along rails to achieve velocities going up to several thousand of metres per second by means of magnetic repulsion without using an explosive propellant. The overall efficiency of the rail gun depends on the rail gun design and its pulsed power supply (PPS) system. The aim of this work is to analyze the performance of rail gun using computer simulation techniques which can be used as a design tool to acquire conditions for the best performance. In this work, finite element analysis software package named Maxwell Electro Magnetic Field Solver is employed to calculate the rail gun key parameters such as magnetic field generated by the rail current, current density in the rails, inductance gradient of the rails, repulsive force acting on the rails, and temperature distribution inside the rails using A.C eddy current analysis. In this work, an attempt is made to extract an empirical formula, which can be used to compute the L of the rails, using curve fitting software called Oakdale Data Fit Engineering. This software uses regression analysis technique to obtain the empirical formula for the given set of data. Generally, the PPS is made up of modules called Pulse Forming Network (PFN s). The PFN is connected to choice of energy sources. Due to constraints on compact power source feasibility study is being carried out by the Government of India and Anna University Chennai to design pulsed power supply capable of storing the energy of 500-kJ, which can be used to accelerate the projectile at a velocity of 1000 m/s to 1500 m/s. To carry out this study in this work, different types of pulsed power supplies which produce pulsed output are studied. Finally, work is carried out to give some basic considerations on volume and weight requirements of capacitive PPS systems to be applied for rapid fire of electromagnetic rail guns due to the current status of the investigations by the Government of India. newline