Study of a single-stage electromagnetic launcher
This thesis examines a single-stage barrel-less electromagnetic induction launcher, developed from an arrangement used previously for very high speed, low projectile mass accelerators. The projectile is placed on top of the launch coil, rather than inside the coil, as is more usually the case in both single and multi-stage launchers of this type. The examination is undertaken both theoretically and experimentally, with extensive experimental results being used to test the validity of the theoretical techniques used. The theoretical examination of the launcher is based on two distinct mathematical models, with results provided by the two approaches being compared. The first model uses a 2D electromagnetic finite-element approach, and does not include projectile motion or thermal effects. It is used to establish whether an analysis technique which does not take into account the projectile dynamics is a valid design tool for a single-stage launcher. The second model employs a coupled-circuit approach to take into account both projectile motion and thermal effects, and is used to obtain an accurate estimate of the overall launcher performance. With the aid of the two models the effects of varying many different launcher parameters are examined, including the size and shape of the stator coil and the size, shape and composition of the projectile. The launcher investigation could be based on a number of criteria but here it is primarily based on two; the highest average velocity over a given distance and the shortest time required to travel a given distance from the initial stationary position.