| Title |
Development of a New Correlation for the Heat Transfer Coefficient of Turbulent Supercritical Carbon Dioxide Flow |
| Keywords |
Supercritical state ; 초임계 상태 ; Carbon dioxide ; 이산화탄소 ; Correlation ; 상관식 ; Buoyancy effect ; 부력효과 |
| Abstract |
Numerical simulations are performed to investigate the turbulent convective heat transfer of the supercritical carbon dioxide flows in vertical and horizontal square ducts. The gas cooling process at the supercritical state experiences a sudden change in thermodynamic and transport properties. This results in the extraordinary variations of the heat transfer coefficients in the supercritical state, which are much different from those of single or two phase flows. Algebraic second moment closure which can include the effects of large thermophysical property variations of carbon dioxide and of buoyancy is employed to model the Reynolds stresses and turbulent heat fluxes in the governing equations. The previous correlations for the turbulent heat transfer coefficient for the supercritical carbon dioxide flows couldn't reflect the buoyancy effect. The present results are used to establish a new heat transfer coefficient correlation including the effects of large thermophysical property variation and buoyancy on in-duct cooling process of supercritical carbon dioxide. |