Effect of geometrical parameters on natural convection of water in a narrow annulus

Numerical analyses have been performed to study the influence of geometrical parameters during natural convection of water in a narrow annulus. A Computational Fluid Dynamics (CFD) model is developed using ANSYS Fluent and validated against the experimental as well as numerical results available in literature. The simulations are performed for different geometrical parameters with radius ratio ranging from 1.1 to 36, aspect ratio is varied from 150 to 650 and inclination from 30° to 90°. It is observed that Nusselt number increases linearly with radius ratio while as a power law function with inclination. Further, with an increase in aspect ratio, Nusselt number decreases and follows a power law function. It is also inferred that Reynolds number increases linearly with aspect ratio and inclination while it decreases with radius ratio (power law).