ISSN Online: 2377-424X
ISBN Print: 978-1-56700-474-8
ISBN Online: 978-1-56700-473-1
International Heat Transfer Conference 16
NUMERICAL STUDIES ON THE COUPLED HEAT TRANSFER CHARACTERISTICS OF SUPERCRITICAL PRESSURE CO2 UNDER COOLING CONDITION
摘要
Heat transfer characteristics of supercritical pressure CO2 (S-CO2) cooled in a straight double-tube are studied numerically in this manuscript. The effects of heat flux, mass flux, turbulence kinetic energy and buoyancy force on the heat transfer and fluid flow are analyzed respectively. The results show that heat transfer behavior changes greatly as the mass fluxes in both sides and the flow direction vary. The heat transfer enhancement becomes larger and larger with the increase of the ratio of heat flux and mass flux when the bulk temperature is larger than the pseudo-critical temperature. Under the same flow direction, turbulence kinetic energy boosts the heat transfer and buoyancy force improves the heat transfer enhancement. The turbulence kinetic energy is the largest in upward flow under the same other conditions. The secondary flow caused by buoyancy effect enhances the flow and heat transfer in horizontal tube, and
the heat transfer coefficients in both upward and horizontal flows are almost the same and are larger than that in downward flow.