Experimental investigation of conduction heat transfer in a rotary drum using infrared thermography

A technique for studying heat transfer in a rotary drum is proposed using infrared (IR) thermography, which is used to record images to give instantaneous thermal data. In this work, the calibration procedure and methodology used to extract temperatures of the particles and the drum wall from the IR camera is discussed. The technique provides insightful information on the flow regimes and heat transfer for varying drum fill levels and rotation rates. The flow profile of the particle bed for each run is analyzed both theoretically using Froude number and experimentally using recorded IR images. The results suggest that the flow of particles is influenced by particle-particle friction in the presence of heat transfer. A transition in the flow profile is observed as time progresses and the bed reaches a surging regime. Higher rotation rates result in maximum average bed temperatures, whereas fill level does not have a conclusive effect.