Launch process of augmented electromagnetic railgun under nonideal condition

In the paper, the simulation and the experiment were carried on a kind of planar series augmented electromagnetic rail launcher. Different from other researches on electromagnetic launcher's analysis, many practical effects were fully considered in launching process such as friction force, air resistance, heat generation and so on. Launching process and armature movement in bore were divided into several key sections. 1) The armature was in a static state when its Lorentz force was less than friction force, though current had passed through the rails and the armature; 2) The armature began to accelerate when its Lorentz force was more than resistance force; 3) Friction force between the armature and rails reduced greatly. A layer of molten metal liquid film was formed on the contact surface because friction heat and joule heat were produced in movement which made the metal layer between the armature and rails melting. And it could lubricate the contact surface and decrease friction coefficient. Results demonstrate that the muzzle velocity is certain related to size of armature, surface smooth degree, precision and other volatile elements.