Numerical simulation study on the heat transfer characteristics of the tube receiver of the solar thermal power tower

In a solar thermal power tower system, a molten salt tube receiver is a significant component. However, the tube flow performance is different with other tubes, half the circumference of the tube is heated with a different heat flux and half that circumference is insulated. As the properties of molten salt change with the temperature along the alloy tube wall, the distributions of temperature and heat flux and the heat transfer characteristics are very complex. The present study uses the computational fluid dynamics to reveal these phenomena. The results show that the temperature distribution of molten salt and tube wall are very uneven whether in an axial or radial direction, and the temperature of the inner tube wall is an important parameter for preventing the decomposition of molten salt. The heat flux of the heating surface increases with the increase of velocity; however, the situation is just the opposite for the adiabatic surface. The heat transfer coefficient is higher as compared with the Sieder-Tate equation. The value of the local Nu number is almost unchanged with the change of the cosine angle over all circumferential direction. (C) 2011 Elsevier Ltd. All rights reserved.