Abstract: A multiscale procedure models the growth of fluid-suspended particles through phase transition and/or agglomeration. The particle deposition on fluid flow boundaries and the precipitation occurred on the solid/liquid interface will influence and potentially constrict/block the fluid flow. The multiscale Lagrangian/Eulerian model enables detailed predictive simulations of the deposit formation and aging processes due to the continued precipitation on the deposit interface and deposition processes of precipitated solids, such as wax crystals or asphaltenes, on boundaries like walls exposed to fluid flow.