Transient mixed-lubrication and contact behavior analysis of metal liquid film under magneto-thermal effect

To investigate the contact state and interface behavior of the armature-rail (A/R) interface under magnetothermal shock, this study employs the lubrication theory and considers the coupling effect of electromagnetic and temperature fields. A transient mixed hydrodynamic lubrication model is established using the finite difference method. The study investigates the evolution mechanism of rough surface metal liquid film, electrical contact behavior, and transient mixed lubrication characteristics at the interface under complex magnetothermal excitation. The study suggests that the electrical contact behavior of the metal liquid film during electromagnetic launch process exhibits significant fluctuation characteristics, which have a crucial influence on the temperature distribution of the metal liquid film. Moreover, due to the fluctuation behavior of electrical contact and factors such as surface roughness, the temperature of the metal liquid film exhibits a complex spatial distribution pattern. The temperature peak continuously increases as the electromagnetic launch progresses. Furthermore, the initially uniform distribution of the metal liquid film gradually transforms into a non-uniform, island morphology due to the joint action of the magneto-thermal effect. However, the liquid metal film still exhibits excellent lubricating properties, which play a crucial role in reducing friction and wear in the electromagnetic launcher system (EMLs).