Smoothed particle hydrodynamics simulation of transient heat transfer within rotary kiln

Rotary kilns are widely used in industries to heat or cool various materials. Previously the heat efficiency of rotary kiln is often evaluated by assuming the temperature is uniformly distributed within the particle bed, while lacking insights into the recirculating particle flows and the resulted non-uniform heat transfer. Here a smoothed particle hydrodynamics (SPH) approach is deployed to study the particle flow and particle–particle, particle–wall heat transfer in the rotary kilns. The results reveal that there exist low-temperature regimes in the core of rotary kilns depending on the filling levels. The temperature distribution is thus nonuniform and closely related to the particle flow pattern. In terms of heating efficiency, the thermal conductivity of particles exerts the greatest influence on the total heat transfer in rotary kiln. Other material and operational parameters, including the rotating speed, filling level, thermal load, and internal friction of particles, also remarkably affect the heat transfer according to the present simulation results, which are of significance to optimize the heating efficiency of rotary kiln.