Detrimental effects of dust deposition in pores of an open volumetric air receiver

Recently the novel concept of solar convective furnace based on open volumetric air receiver is proposed and evaluated for metals processing. The use of open volumetric air receiver is motivated by the need of hot air at about 750 K. It is well-accepted that the dust deposition will be a major challenge for implementation of open volumetric air receiver in the arid deserts, worldwide. In this paper, some of its detrimental consequences pertaining to flow instability and absorber temperature are presented. A pressure-drop correlation for straight pore based absorber is developed for analyzing the flow instability. A two-dimensional validated approach is adopted for analyzing the receiver overheating as a result of dust deposition forming a so-called insulation-type layer on the inner surface of absorber pore. The findings show stable flow regime with a uniform thickness of the deposited dust layer (100 μm & 200 μm) on the inner surface of a pore. The thickness of dust layer is more detrimental in view of substantial rise of absorber temperature and thus, the sustainability of the open volumetric air receiver needs to be addressed. The presented details are both encouraging and alarming, addressing some of the gaps and outlining the need of an in-situ cleaning approach for operating such a system in the arid deserts of India and worldwide.