Abstract
In an electromagnetic rail launcher, a metal liquid film is created at the armature/rail (A/R) contact interface. It has a significant impact on electromagnetic launch performance. In this paper, an electromagnetic-elastic mechanics-hydrodynamics multi physics coupling model is established in consideration of the metal liquid film’s own acceleration, magnetic pressure and dynamic changes in film thickness. Based on this model, the lubricating characteristics of magnetic pressure and fluid pressure distribution, film thickness distribution and velocity distribution of the metal liquid film were studied. When the velocity of the metal liquid film is very fast, and the magnetic pressure is reduced, it may fail to maintain stability and rupture, which may be an important reason for the transition. Finally, this paper analyzes the lubrication effect of the metal liquid film, and points out that when we want strictly to control the muzzle velocity, the lubrication effect of the metal liquid film must be considered.
Highlights
Electromagnetic launcher can convert the electromagnetic energy provided by the high-power pulse power source into the kinetic energy of the payload, and utilize the electromagnetic force to drive the projectile to accelerate between two rails, the projectile can obtain an ultra-high velocity of 2500 m/s or more
P direction, the x-axis femag is the lorentz on the liquid film the longitudinal direction, which where, is the fluid pressure, the shear force that theinliquid film infinitesimal element allows to be represented by a magnetic f emag pressure, ρ is density of liquid film, aa is the acceleration of the receives in the x-axis direction, is the lorentz forces on the liquid film in the longitudinal armature, a f is the self-acceleration of the film
The film thickness of the metal liquid film is combined and converted into the Reynolds equation using a simple algebraic combination, and the obtained fluid pressure is combined with the electromagnetic pressure to generate a new film thickness
Summary
Electromagnetic launcher can convert the electromagnetic energy provided by the high-power pulse power source into the kinetic energy of the payload, and utilize the electromagnetic force to drive the projectile to accelerate between two rails, the projectile can obtain an ultra-high velocity of 2500 m/s or more. In studying properties of the metal liquidof film, Jinming acceleration magnetic pressure; she ignored the effectpressure; of the dynamic changes in film the effects of and the metal liquid film’s own acceleration and magnetic she ignored thickness onthe thedynamic characteristics of in thefilm liquid film [21,22]. In thethe dynamic changes of film thickness, the effects of theof liquid film’s film’sacceleration own acceleration and magnetic and thenanestablish an electromagnetic-elastic own and magnetic pressure, pressure, and establish electromagnetic-elastic mechanicsmechanics-hydrodynamics multiphysics coupling. Wethis thenmodel use this model tothe analyze the hydrodynamics multiphysics coupling model.
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