A 3-D Magneto-Elastohydrodynamic Model of Liquid Metal Film at Rail–Armature Interface

Abstract

To make a deep investigation into the lubrication characteristics of the liquid metal film (LMF), the existing 2-D hydrodynamic lubrication models cannot meet the requirement as it fails to describe the flow of the liquid film at the transverse direction. This article makes the first step toward a 3-D model of the LMF at the armature/rail (A/R) interface. A 2-D Reynolds equation is derived considering the self-acceleration of the film and the Lorentz force acting on it. By coupling the electromagnetic fields, stress, and fluid fields, a magneto-elastohydrodynamic model is established completely. Based on this, the distribution characteristics of the LMF are explored which includes the distribution of the film thickness, hydrodynamic pressure, and fluid velocity. Besides, the dynamic characteristics of the LMF in the launch process are analyzed. The results show that: 1) the LMF is trapped in an arching gap in the transverse direction. The liquid pressure is symmetrically distributed along the centerline. In addition, the positive transverse fluid velocity indicates the jetting of the molten metal which may do damage to the bore. 2) At the current down-slope, the film thickness and liquid pressure both decrease rapidly which may put the film at risk of break. This article can provide a reference to the modeling of LMF hydrodynamic lubrication and help to understand the flow behavior of the liquid film.