Influence of Property Variation on Natural Convection in an Isothermal Vertical Finned Channel: An Extended Study

Boussineśq and non-Boussineśq fluid with thermo-physical property variation have been investigated for a vertical fin array. Computations are executed for the range of parameter such as Grashof number 1.86 × 10⁵ and 4.42 × 10⁵, non-dimensional S* = 0.2, 0.3, and 0.5, and non-dimensional clearance C^* = 0.10, 0.15, and 0.40. The axial development of various fluid flow quantities, such as the pressure defect (P*), local Nusselt number (Nu_l), and the bulk temperature of the fluid (θ_b) has been presented for each of the property combinations. Nu_l is observed to have reduced by 70% near the exit from the Boussineśq fluid with fixed viscosity and thermal conductivity to the non-Boussineśq fluid with the variable property. Furthermore, the overall Nusselt number (Nu) at S* = 0.2 in an isothermal vertical fin array for an increase in Gr from 1.86 × 10⁵ to 4.42 × 10⁵ with different combination of properties such as Boussineśq fluid with fixed viscosity and thermal conductivity (ρb μc kc), Boussineśq fluid with variable viscosity and thermal conductivity (ρb μv kv), non-Boussineśq fluid with fixed viscosity and thermal conductivity (ρv μc kc), and non-Boussineśq fluid with variable viscosity and thermal conductivity (ρv μv kv) are observed to have an increase of 138%, 148%, 150%, and 160%, respectively.