Experimental and numerical study of conductive heat transfer in aggregate particles using a flighted, rotary drum

Abstract

Heating aggregates and recycled materials is an energy intensive part of the process of producing asphalt pavement. Sustainability can be improved by increasing the portion of recycled materials while decreasing the energy required to produce the asphalt mixture. A common method to incorporate recycled materials is to mix heated aggregate with cold recycled materials. Interstitial gas conduction is the dominant mode of heat transfer in this process due to the low thermal conductivity of these materials. In this study, a particle-based model that includes the contribution of the interstitial gases was validated with a novel experimental method using infrared (IR) thermography to track the temperature evolution of a mixture of hot and cold aggregates in a flighted, inclined drum. The simulation results showed good agreement with the experiment demonstrating the model’s ability to capture the heat transfer and the particle flow in the dynamic system of irregular shaped particles.