Dynamic Modeling of Critical Velocities for the Pushing/Engulfment Transition in the Si-SiC System Under Gravity Conditions

Abstract

An extended non-steady-state model for the interaction between a solid particle and an advancing solid/liquid interface based on the dynamic model of Catalina et al. (Metall Mater Trans A 31:2559â2568, 2000) is used to calculate the critical velocities for the pushing/engulfment transition in Si-SiC system under microgravity and under normal gravity conditions. The aim of this study was to explain the abnormal behavior of the critical velocity in experiments. The simulations were carried out for two cases of the drag force formulation. The effects of the non-spherical form of the particles as well as the cluster formation were also taken into account. It is found that in the presence of the gravity force, the particles will be engulfed when the particle size exceeds a certain limit which does not depend on the choice of the drag force formulation

The behaviour of plasma-functionalized graphene nanoflake nanofluids during phase change from liquid water to solid ice

“…The entrapment process is usually modelled as a balance between drag forces, which push the particles towards the solid front, and repulsive Lifshitz-van der Waals forces, which push the particles into the liquid bulk. [39][40][41] Typical assumptions in these models include spherical particle shapes of 10 to 50 μm in diameter. Thus no Brownian or buoyancy effects are present in these systems.…”

“…39 Recently, however, more advanced models for non-spherical particles, which have greater drag forces, have been developed. 40 O-GNFs likely have increased drag forces from their square prism shape, and from the concave structure of the interface, and thus are disposed to incorporation within the solid. However they also have Brownian dispersion from their hydrophilic surface groups and are at sizes orders of magnitude smaller than in previous studies.…”

“…However, the multitude of parameters that may influence the inclusion of particles make categorizing this behaviour much more complicated. The entrapment process is usually modelled as a balance between drag forces, which push the particles towards the solid front, and repulsive Lifshitz-van der Waals forces, which push the particles into the liquid bulk [39][40][41]. Typical assumptions in these models include spherical particle shapes of 10 to 50 µm in diameter.…”

“…Thus no Brownian or buoyancy effects are present in these systems [39]. Recently, however, more advanced models for non-spherical particles, which have greater drag forces, have been developed [40]. O-GNFs likely have increased drag forces from their square prism shape, and from the concave structure of the interface, and thus are disposed to incorporation within the solid.…”