Numerical investigations of structural modification and particle geometric parameters on the heat transfer performance of falling particle solar receiver

Falling particle solar receiver (FPSR) has higher operation temperature, lower investment, higher pressure bearing capacity and more direct heat energy storage than those of traditional tube receiver. The FPSR is usually arranged with an opening aperture to avoid the loss of reflected solar radiation. Thus, they have not been widely employed in commercial plants due to the convective and radiative heat loss through the aperture. In this contribution, in order to reduce the heat loss through the aperture, we analyze the arrangement of the particle curtain and aperture, the effect of particle diameter on the deformation of particle curtain. The results show that the particles temperature of reaching bottom Tb and the maximum temperature Tmax is related to the particle diameter ds, and the difference between Tmax and Tb, ΔT, decreases with the increase of ds. Moreover, raising the distance between aperture and bottom surface can increase the particle temperature up to 63.6K. In addition, the particle diameter size will lead the deformation of particle curtain and furthermore lead to an ununiform temperature distribution of the particles. The numerical results show that ΔT of particles at the same height is up to 142.7K. Finally, we add the air nozzles at the aperture and found that increasing the temperature of the nozzle jet stream can effectively increase the particle temperature. This contribution can provide a guidance for the design of falling particle solar receivers.