Natural convection heat transfer of cold water in an eccentric horizontal cylindrical annulus - A numerical study

A numerical study of the natural convection heat transfer of cold water, having the density inversion between two isothermal eccentric horizontal cylinders is studied. A general code is developed for the body fitted coordinate system. This procedure transforms an arbitrarily shaped physical domain into a rectangular (square) domain. The governing equations in this computational domain are solved by the upwind finite difference scheme. The numerical solutions are obtained for a Rayleigh number (Ra) ranging between 10(3)-10(5), a Prandtt number (Pr) 12.0 and inversion parameter (gamma) 0, - 1 and - 2. The affect of the radius ratio (R) on the dow patterns and heat transfer coefficients is studied by taking the Radius ratio as 1.5 and 2. The eccentricity affect is studied by moving the center of the inner cylinder horizontally and vertically (both positive and negative directions) with respect to the center of the outer cylinder. For the cases considered in the present study, it is again for gamma = - 1, the minimum heat transfer is observed like in the case of concentric annulus.