Turbulent Natural Convection In A Semicircular Geometry Containing Internal Heat Sources

Abstract

This paper deals with the computational modeling of buoyancy-driven turbulent heat transfer involving spatially uniform volumetric heat sources in a semicircular geometry. The Launder & Sharma low-Reynolds number k-e turbulence model and the SIMPLER computational algorithm, which was incorporated into the CORE-TNC computer code, were used for the numerical modeling. The numerical model was subsequently benchmarked with experimental data from the hemispherical-shaped Mini-ACOPO test facility for the modified Rayleigh number range of 2x 10^ < Ra' < 7x 10'*. The general trends of flow patterns, temperature fields, local heat flux distribution, and average Nusselt numbers etc. from this numerical investigation showed very similar results to those observed in the experimental investigations by Jahn & Reineke, by Mayinger, and by Theofanous. However, the local fluid temperatures and velocities continuously exhibited oscillatory behavior during the iteration process. Employing several techniques such as near-wall treatment functions of D and E, grid size adjustment, underrelaxation factor, and pseudo-transient approach were utilized to minimize nonperiodic numerical oscillatory behavior during the iteration process.