Abstract
Thermal convection and heat conduction in a rotary kiln are investigated through a numerical flow simulation based on the three-dimensional unsteady Navier-Stokes equations. In order to deal with thermal flow phenomena, an extended version of the MAC method 1) is employed, and with respect to discretization of convective terms, the third order upwind scheme 2) is introduced. For an actual design of the furnace, two phenomena have to be solved simultaneously although there is a large difference for timescale between thermal convection of gas and heat conduction of solid. In this study, we employed some numerical techniques in order to overcome this problem. A thermal calculation routine is separated into two parts or thermal convection and heat conduction calculations, and thermal modification is carried out on the boundary region between gas and solid. Furthermore, a rotation of the furnace is considered in this simulation, and effects of its rotation to heat transfer are also discussed. Through this simulation, not only three-dimensional flow structures but also thermal distributions in a rotary kiln are solved and visualized.
