Theoretical Investigation of Boundary Layer Behavior and Heat Transfer of Supercritical Carbon Dioxide (sCO2) in a Microchannel

Carbon Dioxide (CO
₂
) is a promising fluid for a range of thermal applications, such as power cycles. Supercritical CO
₂
(sCO
₂
) around the critical conditions experiences large variations in its physical properties, such as density, viscosity, specific heat and Prandtl number. Because of that, accurate modeling of the heat transfer process around the critical state is a challenging task. In the current study Computational Fluid Dynamics (CFD) steady state analysis of sCO
₂
flow in a plain microchannel with a hydraulic diameter of 300 μm and length of 14.08 mm was simulated using Starccm+. The inlet temperature was held constant at 295.65 K and the pressure at 7.84 MPa. The surface temperatures of the heater at specified locations were measured and compared against experimental results. In this work the flow of sCO
₂
was simulated over a wide range of temperatures where the properties change drastically. Also, the accurate modeling techniques ensured that the density patterns observed in the experiments captured in the simulation.