Abstract
Numerical simulations have been performed to investigate the flow and heat transfer characteristics of near-critical and supercritical CO_2) in the thermally driven high pressure CO_2, circular system proposed by the authors by using of a CFD code, FLUENT. Since the flow can be easily turbulence due to its low kinematic viscosity, the renormalization group (RNG) k-c model was adopted to account for the turbulent flow appropriately. The physical property temperature dependence of CO_2 was considered with piecewise-linear profile (properties vs temperature) under constant pressure. It was found that M-shape radial velocity profile of heating zone was developed by sharply high flow near the wall and relatively slow main flow and that the average circulation flow rate was comparable to that measured by tracer method.
