Double-Diffusive Laminar Natural Convection in A Symmetrical Trapezoidal Enclosure

The objective of the present investigation is to study the laminar natural heat and mass transfer in a symmetrical trapezoidal enclosure. The base and ceiling are isothermal and isoconcentration surfaces, while the lateral walls are considered adiabatic and impermeable. A mathematical model is derived and solved numerically. Both aiding and opposing buoyancy forces have been studied. The investigation is made for wide range of buoyancy ratio N, -1 ≤ N ≤ 10, inclination angle φ,0° ≤ φ ≤ 18.44°, Lewis number Le, 1 ≤ Le ≤ 5 and thermal Grashof number Gr_T, 2x10³<Gr_T<5x10³ with fixed aspect ratio A, at A=3, and Prandtl number Pr, at Pr=0.7. The effect of Lewis number, buoyancy ratio and thermal Grashof number on both average Nusselt and average Sherwood numbers are studied as well as the average Nusselt and Sherwood numbers were correlated in terms of buoyancy ratio and Lewis number. A comparison is made with the previous experimental and numerical results. The comparison shows a maximum deviation from – 5% to +12.8%.