Study Of Heat Transfer And Mechanical Characteristics Of Thermal Receiver For Solar Tower Power Generation System

With the increasing shortage of non-renewable energy,the utilization situation of energy is facing great challenges.As one of the most promising renewable energies,solar energy is not only inexhaustible but also clean and pollution-free.Taking the utilization of tower solar thermal power as the background,the molten salt solar receiver tube with the semicircular non-uniform heat flux density is chosen to be the research objective in this paper.By using the CFD simulation and theoretical calculation approaches,the influence evaluations of five typical parameters(i.e.,the internal diameter of receiver tube,receiver tube wall thickness,inlet molten salt temperature,inlet molten salt velocity and incident heat flux density)on both the heat transfer and mechanical characteristics of the solar receiver are launched.The main completed works and conclusions include:First,a numerical model of the 3-D molten salt solar receiver tube with the semicircular non-uniform heat flux density is established.When all initial parameters are settled,the flow and heat transfer process of the molten salt in the receiver tube is simulated.The results demonstrate that the molten salt temperature increases with the receiver tube height increased.For a certain cross section of the receiver tube,the temperature distribution is non-uniform,and the temperature decreases in the decreasing direction of the gradient of heat flux density.Secondly,the influences of the five typical parameters mentioned above on the heat transfer characteristics of the solar receiver are investigated.The analysis results indicate that the heat transfer between the molten salt and receiver tube can be enhanced by reducing the internal diameter of receiver tube or by increasing the inlet molten salt temperature,inlet molten salt velocity and incident heat flux density properly.The impact of the receiver tube wall thickness on the heat transfer performance of the solar receiver is relatively small.Finally,based on the heat transfer characteristic analysis of the molten salt solar receiver,the effect evaluations of the five typical parameters on the mechanical performance of the solar receiver are conducted.The analysis results reveal that the proportional relationship exists between the equivalent thermal stress of the receiver tube and the internal diameter of receiver tube(or the receiver tube wall thickness,incident heat flux density).The equivalent thermal stress of the receiver tube has the inverse relationship with the inlet molten salt temperature or the inlet molten salt velocity.In terms of the mechanical performance,the mechanical performance of the solar receiver can be improved by reducing the internal diameter of receiver tube,receiver tube wall thickness and incident heat flux density,or by increasing the inlet molten salt temperature and inlet molten salt velocity properly.