Pressurized Carbon Dioxide as Heat Transfer Fluid: In uence of Radiation on Turbulent Flow Characteristics in Pipe

The influence of radiative heat transfer in a CO2 pipe flow is numerically investigated at different pressures.Coupled heat and mass transfer, including radiation transport, are modeled. The physical models and the high temperature and high pressure radiative properties method of computation are presented. Simulations are conducted for pure CO2 flows in a high temperature pipe at 1100 K (with radius 2 cm) with a fixed velocity (1 m·s-1) and for di erent operating pressures, 0:1, 1, 5 and 20 MPa (supercritical CO2). The coupling between the temperature and velocity fields is discussed and it is found that the in uence of radiation absorption is important at low pressure and as the operating pressure increases above 5 MPa the influence of radiation becomes weaker due to an increase of CO2 optical thickness.