Modelling the morphology of crystalline deposits evolving from impinging droplets of salt solution

The work here develops a new moving boundary model which adapts and advances a technique initially used for the purpose of modelling geological formations to predict the morphology of crystallising droplets of salt solution. A multiphase Volume of Fluid (VOF) CFD model coupled with a scalar advectiondiffusion transport equation is used to capture the flow and concentration of the solution. By utilising userdefined routines, we are able to couple the models for the solution flow with a crystal growth model. This coupled model captures the growth of the overall bulk crystalline formation by the use of moving boundary techniques with dynamic remeshing of the numerical grid. In this paper an axisymmetric representation of the model is presented that describes the crystal growth through time. The model is compared against data from an experimental study using a simulant salt solution (Sodium Nitrate) where physical parameters and growth rates predicted by the model are in good agreement with those observed in experiments. These studies provide information for the safety assessment when considering heavy metal solutions for various fault scenarios.