Numerical study on preheating process of molten salt tower receiver in windy conditions

Abstract

In the preheating process of the molten salt tower receiver, the thermal stress is large and the over-temperature problem is prone to occur. The finite volume method and two-dimensional thermoelastic method are combined in this paper to study the preheating process of the receiver tube in windy conditions. The experimental results of a lab-scale receiver verify the numerical model. Then, the influence of heat flux, wind speed, wind direction, ambient temperature and uniformity of heat flux distribution on the preheating process is explored. Finally, the influence of salt filling temperature and salt filling mass flow on the salt circulating is also revealed. The results indicate that the increase in heat flux, decrease in wind speed and increase in ambient temperature decrease the preheating time. The wind in the direction of 30° from the front side of the tube has the greatest influence on the preheating process. Compared with the no-wind condition, the preheating time increases by 177.5%. The maximum tube wall temperature and thermal stress are significantly higher under non-uniform heat flux distribution than those under uniform heat flux distribution. The salt inlet temperature and salt inlet mass flow respectively affect the stable value and reduction rate of thermal stress.