Simulation Of The Solar Tower Receiver And Experimental Study On Particle Insulation

The solar power system includes tower solar thermal power generation system,parabolic through solar thermal power generation system,dish-stirling solar thermal power generation system,linear fenier-type solar thermal powe generation system.The tower solar thermal power generation system includes some main parts:heliostat field,tracking system,receiver,tank of molten salt,heat exchanger and generating system.The receiver is the key of the whole system.Its safety and thermal efficiency directly determine safety and thermal efficiency of the whole tower solar thermal power generation system.In this paper,a 3-D model of the tower solar thermal power receiver is established.Fluent——a CFD commercial software is used to simulate different heat fluxes,inlet velocity,surface coefficient of heat transfer and environmental temperature on receiver performance.The results show that the outlet temperature of the molten salt increases and the thermal efficiency increases with the increase of ambient temperature or the increase of the heat flux or the decrease of the surface coefficient of heat transfer.When the surface coefficient of heat transfer increases from 20 W/(m2·K)to 140 W/(m2·K),the heat loss rate increases from 8.28%to 17.77%,and the thermal efficiency decreases from 91.72%to 82.23%.The result shows that the wind speed has a great impact on the thermal efficiency of the receiver.The tower solar thermal power receiver works in a complex weather conditions.In a natural cooling process,the temperature of the molten salt receiver tube decreases to the point below the molten salt freezing point.In order to prevent the occurrence of molten salt solidification in the receiver tube,a new method and device for thermal insulation of tower solar thermal power generation is put forward,which has the advantages of low material cost,simple system control,rapid response,etc.Compared with the bare receiver tube,the average temperature of the receiver tube with a 6mm particle insulation layer takes 10 times time to drop from 500? t0 230?The experimental results show that the factors such as the temperature of particles,the thickness of particles,the ambient wind speed,the windward surface and the leeward surface have a great influence on the temperature of the receiver tube.The higher the temperature of particles,the thicker the thickness of particles,the smaller the environmental wind speed,the better of the thermal insulation effect.The thermal insulation effect of windward surface is worse than that of leeward.A 3-D model of the tower solar thermal power receiver is established and verified with the experimental results.The influence of different particle temperature on the thermal insulation effect is investigated under the certain temperature of the receiver tube.The average temperature of the particle is higher the better of the thermal insulation effect.