Abstract
A low thermal conductivity in feedstock material and high plasma temperatures generally lead to inhomogeneous heating of particles in plasma spraying. Existing modeling methods can determine heat transfer within idealized spherical particles with homogenous morphology, but in many cases, particles have an agglomerated morphology, consisting of multiple smaller particles that are packed together. The reduced contact area between the individual smaller particles results in a drastic reduction of the effective thermal conductivity of the agglomerate. On the other hand, it enhances heat transfer from the plasma gas due to the increased particle surface area and penetration of the hot plasma into the agglomerate. Moreover, the momentum transfer from the plasma to the agglomerate differs from that of a homogenous spherical particle, which can significantly affect heating dynamics. This paper presents a novel particle modeling approach that accounts for all such phenomena. Differences in kinematics and heating dynamics of the agglomerates are analyzed with regard to their packing densities.
