Collisions between particles in multiphase flows: Focus on contact mechanics and heat conduction

The topic of heat transfer between colliding particles or between particles impinging on solid surfaces is, in spite of its practical significance, still not widely studied in literature: efforts have, till now, led to only a handful of models. At the same time this problem is crucial not only for many types of multiphase flows but also for other systems involving colliding bodies. Therefore the first objective of the research was to study heat conduction between colliding particles for the case when the local deformation in the contact region can be treated as consisting of two regions: one deformating elastically and the other plastically. This requires investigation of collision dynamics and therefore this paper also contains a short review of the existing models for modelling particle-particle and particle-wall collisions. The second important result of the work presented here is a new relation for the coefficient of restitution that was developed by fitting a dimensionless relation involving the salient physical parameters to numerical experiments based on collision models.