An investigation of natural convection in a three dimensional tapered chimney without Boussinesq assumption

Natural convection in a three dimensional tapered chimney is investigated numerically. In order to investigate the natural convection under a high temperature difference situation, Boussinesq assumption is not adopted instead of consideration of the compressibility of fluid. Methods of Roe scheme, preconditioning and dual time stepping are used to solve governing equations for a low speed compressible flow. Coordinates transformation of algebraic grid generation and non-reflecting boundary condition are used to facilitate computation processes. The results reveal that in the expanding duct local Nusselt numbers distributed around the corner region are larger than those distributed around the central region. An available correlation equation is proposed and is well consistent with the numerical results.