Modelling the effect of vibrations on the surface tension of a liquid droplet using meshless methods

Application of vibration impacts for purposeful influence on such processes as drop formation, melt bath formation and crystallization of welding bead allows to control heat and mass transfer in liquid, crystallization process and shape of bead in technological processes of welding. Impact of vibration influences on nature of motion of liquid in the drop, which is reflected in the change of value of surface tension coefficient, is considered in the article. The mathematical model of the liquid flow considering surface tension force in formalism of smoothed particles hydrodynamics method is offered. This method allows direct consideration of the vibration effect by introducing additional boundary conditions. Verification of developed mathematical model is conducted in comparison with in-situ experiments, in which dependence of surface tension coefficient value on amplitude of speed of vibration influences was determined. To determine surface tension coefficient two methods were implemented: pending drop method and stalagmometric method. The implemented model satisfactorily describes the effect of decreasing surface tension coefficient for water. A series of numerical experiments for determining the effect of vibration influences on the value of surface tension coefficient for 12X18H10T steel grade was carried out. It was found that at vibration with speed amplitude equal to 2.0 m/s the decrease of surface tension coefficient value by 30 % is observed. Decrease in surface tension coefficient should facilitate the realization of continuous flowing of metal from the wire, which may positively influence the formation of metal during wire surfacing. Thus, the proposed mathematical model can clearly simulate the effect of vibration effects on the value of the surface tension coefficient and will allow the effect of vibration effects in additive manufacturing to be investigated in the future.