In this paper laminar free convection heat transfer from a horizontal isothermal elliptic tube placed in a micropolar fluid with its major axis vertical is investigated. The governing equations basd on the conservation of mass, linear momentum, angular momentum and energey are numerically solved using the Fourier Spectral method. The main controlling parameters, beside the material parameters of the micropolar fluid, are the Rayleigh number, the Prandil number and the elliptic section axis ratio The micropolar fluid parameters are the vortex Viscosity, micro-inertia density and Spin gradient viscosity The results, which were obtained for a range of these parameters, were carried Out. at two axis ratios of 0.5 and 0.025. The axis ratio of 0.025 approximates the geometry of the special case of vertical flat plate. The results for vertical plate placed in Newtonian fluid arc compared with the relevant results in the literature and very good agreement was obtained. The study has shown that the vortex viscosity is the frost influencing material parameter on heat transfer rate.
The study showed that as the vortex viscosity increases the heat transfer rate decreases.