The Effects of Surface Roughness on Heat Transfer between Two Contacting Particles

An investigation was carried out to draw a similarity between contact heat transfer and current for two contacting spherical particles where the results can be used for the discrete element method (DEM) simulation. The experimental work is presented in two conditions of mechanical contact phenomena i.e., static contact and dynamic contact, respectively. Nevertheless, for dynamical contact, it is hard to obtain heat transfer directly during the collision. Hence, the authors attempted to use current according to the analogy between heat transfer and current. This paper firstly examined the contact phenomena under the static contact condition. The analysis was based on the contact forces on the particles as well as the surface roughness parameters of the particles. It is found that contact heat transfer and current which flow through a spherical surface have a good similarity in the way they were affected by the surface roughness of the particles. Both contact heat transfer and current increase as surface roughness becomes large. However, this is not a common trend because larger surface roughness yields larger contact resistance. Using the similarity, a simple relation between contact heat transfer and current on two contacting particles (spheres) was introduced. This empirical relation can be used to estimate the heat transfer in dynamic contact condition