Research on the Influence of Augmented Rail Length and Charging Voltage to System Launch Efficiency

For an electromagnetic launcher (EML), a time-varying current will generate the electric induction force. Moreover, magnitude of the electromotive force depends on the location, speed, and acceleration of the armature. For the series augmented (EML) in the initial part of barrel, the distribution of inductance gradient is influenced by the length of the augmented rails. Besides, both electromotive force and inductance gradient are essential factors to the launch efficiency. For a specific rail structure and time-varying current, the augmented rail length should be optimized to maximize the launch efficiency. In order to research the influence of the augmented rail length to the launch efficiency, a calculation model considering contact resistance, electromotive force and friction force is employed and modified. The model consists of a pulse-forming network power supply (PPS) system and an augmented launcher. By changing the length of the augmented rail, a series of parameters are obtained involving inductance gradient distribution, induced force etc. Based on the results, the efficiency and energy loss distribution are analyzed. Furthermore, the relationship between rail length and launch efficiency is acquired. The results can be used to optimize the railgun design.