Abstract
Direct numerical simulation (DNS) of supercritical CO_2 turbulent channel flow is performed to investigate the heat transfer mechanism of supercritical fluid. In the present DNS, full compressible Navier-Stokes equations and Peng-Robison state equation are used. Due to the effects of the mean density variation in wall normal direction, mean velocity in the cooling region becomes high compared with that in the heating region. The mean width between high-and low-speed streaks near the wall decreases in the cooling region, which means that turbulence in cooling region is enhanced and lots of fine scale eddies are created due to the local high Reynolds number effects. In the cooling region, Nusselt number becomes large due to high thermal conductivity and low kinematic viscosity which cause modification of turbulence structure.
