(A) study of natural convection in the horizontal gap between inner square duct and outer circular cylinder

Abstract

In this thesis, natural convective heat transfer in the horizontal gap between inner square duct and outer circular cylinder has been investigated numerically and experimentally. Flow regime considered is steady laminar flow with the Rayleigh number ranging from $1.0\times10^4$ to $5.0\times10^5$ based on the radius of outer cylinder. Finite element method which is capable of handling irregular geometry as is the case for the present problem is used to solve the Boussinesq approximate equations numerically. Numerical solution is obtained for two different geometries where the line of geometric symmetry aligns with the gravitational direction. Experiment has been also done, measuring temperature field using thermocouple probes. Visualization of flow field has been preformed with tobacco smoke. The result of experiment has provided a good support for the validity of the above numerical calculation.