Effects of soot nanoparticles on heat transfer and flow in fire-tube waste heat boiler

Soot nanoparticles play a key role in heat transfer. A single-phase model is proposed to study effects of soot nanoparticles on heat transfer in a fire-tube waste heat boiler used in the process of bitumen gasification. In this model, the syngas containing a large amount of soot nanoparticles is treated as soot nanofluid. The model is applied in the numerical simulation of heat transfer in a fire tube in the waste heat boiler. Results show that soot nanoparticles enhance heat transfer not only by heat radiation mainly but also by the effects of microscale of soot nanoparticles especially at high temperature. Smaller sizes or larger quantities of soot nanoparticles can intensify heat transfer of the soot nanofluid. It is also indicated that structures of fire tubes affect the temperature and velocity fields significantly. (c) 2012 Curtin University of Technology and John Wiley & Sons, Ltd.