Numerical simulation of double-diffusive mixed convection within a rotating horizontal annulus

A numerical investigation of double-diffusive mixed convection within a two-dimensional, horizontal annulus has been carried out. The outer cylinder was made to rotate in an anti-clockwise direction to introduce the forced convection effect. In addition, the solutal and thermal buoyancy forces are sustained by maintaining the inner cylinder at a uniform but higher concentration and temperature values, respectively. The flow is considered to operate in the laminar regime under steady state conditions. Moreover, the transport equations are solved using the Galerkin weighted residual method by incorporating a non-uniform mesh size. The heat and mass transfer rates were closely examined using several dimensionless groups in a wide domain of operating conditions. The considered domains in this investigation are as follows: 5 {less-than or slanted equal to} Re {less-than or slanted equal to} 150, 0.01 {less-than or slanted equal to} Le {less-than or slanted equal to} 10, 10³ {less-than or slanted equal to} Ra {less-than or slanted equal to} 10⁵, - 15 {less-than or slanted equal to} N {less-than or slanted equal to} 15, 0.7 {less-than or slanted equal to} Pr {less-than or slanted equal to} 10, 0.5 {less-than or slanted equal to} σ {less-than or slanted equal to} 5 and - 0.75 {less-than or slanted equal to} ε {less-than or slanted equal to} 0.75. The whole flow regimes were defined according to the relative values of Reynolds number and solutal and thermal Grashof number. Furthermore, the predictions of the average Nusselt and Sherwood numbers were obtained for the operating range of the Lewis and buoyancy ratio numbers.