| Title |
A Study on the Transient Convective Heat Transfer forSupercritical Water in a Vertical Tube |
| Keywords |
Thermodynamic critical point ; 열역학 임계점 ; Transient ; 천이상태 ; Convective heat transfer ; 대류열전달 ; Vertical tube ; 수직관 ; Pseudocritical temperature ; 준임계점온도 ; Properties ; 물성치 |
| Abstract |
Numerical analysis has been carried out to investigate transient turbulent con-vective heat transfer in a vertical tube for supercritical water near the thermodynamic critical point. Heat transfer and fluid flow in the tube are strongly coupled due to the large variations of thermodynamic and transport properties such as density, specific heat, and turbulent visco-sity. As pressure in the tube approaches to the critical pressure, the properties variation with time becomes larger. Heat transfer coefficient rapidly decreases along the tube near the pseu-docritical temperature at the tube wall forPR<1.2. Stanton number variation with time is largely reduced in the region of gas-like phase in comparison with Nusselt number. Turbulent viscosity ratio close to the wall increases near the pseudocritical temperature and it gradually decreases with time. |