Settlement–adhesion evolution mechanism of dust particles in the flow field of photovoltaic mirrors at night

Abstract

Solar energy is one of the most potential renewable energy sources to solve energy and environmental crises. Dust deposition on the photovoltaic mirrors greatly decreases the working performance of the mirror and the efficiency of photovoltaic power generation. In this paper, the particle settlement–adhesion evolution mechanism in the flow field of photovoltaic mirrors at night is studied using the computational fluid dynamics-discrete element method. In addition, the effects of air inlet velocity, air relative humidity, particle size and mirror installation inclination on particle settlement–adhesion laws are discussed. The research results show that in the free/nonfree settlement–adhesion motion process, due to the great effect of the relative humidity of air, dust particles can settle and adhere to the photovoltaic mirror by the leading role of the particle gravity force and liquid bridge force, respectively. Dust particles can leave from the flow field of the photovoltaic mirror due to the great effects of the particle collision force and drag force. Decreasing the particle settling velocity or dust deposition density can reduce the dust deposition degree on the photovoltaic mirrors. The research results can provide important theoretical guidance for the removal of dust particles from photovoltaic mirrors.