(400t) Heat Transfer in a Rotary Drum Using Experiments and Simulations

Manogna Adepu, Shaohua Chen, Yang Jiao, Aytekin Gel, Heather Emady

Arizona State University, Tempe, AZ 85287

Granular material subjected to agitation is encountered in many practical applications of material processing (e.g. cooling, heating, granulation, and clinkering). Furthermore, many of these applications also involve heat transfer whereby solids face cold or hot surfaces and heat is exchanged not only between individual particles but also between the particles and external surfaces via the particle–particle or particle–surface contact. This work focuses on understanding the heat transfer mechanisms in the granular bed inside a rotary drum, one of the most commonly used process equipment. Experiments are performed using 4 mm diameter silica particles to investigate the granular flow and heat transfer mechanism inside a 3-inch radius and 3-inch long stainless-steel rotary drum. The drum rides on two titanium wheels, precluding the direct contact of the drum wall with the rollers. One side of the drum is closed with a transparent quartz window, which can handle high temperatures. Another side of the drum is closed with a sapphire window, compatible with an IR camera, specifically chosen to give a high transmittance to the infrared light. The setup is designed to handle up to 1000⁰ C, making it possible to study all modes of heat transfer via conduction, convection, and radiation. The wall of the drum is maintained at a desired high temperature using heat guns placed around the drum. A drum tumbler is used to a rotate the drum and the temperature evolution in the particle bed is recorded using Omega thermocouples and a mid-wave infrared (MWIR) camera. All the modes of heat transfer are quantified under varying operation conditions to establish a strong understanding of the heat transport. For this, both experiments and CFD-DEM (using MFIX-DEM, an open source multi-solver suite) simulation techniques are used to analyze the thermal behavior. The digital image analysis (DIA) and the particle image velocimetry (PIV), are combined with IR thermography (DIA/PIV/IR technology [1]) to obtain comprehensive quantitative hydrodynamic and thermal data sets.

 Reference:

[1]. Patil, A. V, Peters, E. A. J. F., Sutkar, V. S., Deen, N. G., & Kuipers, J. A. M. (2015). A study of heat transfer in fluidized beds using an integrated DIA / PIV / IR technique. Chemical Engineering Journal, 259, 90–106.