Detrimental Effects of Dust Deposition in Pores of an Open Volumetric Air Receiver
Abstract
Recently the novel concept of Solar Convective Furnace (SCF) based on open volumetric air receiver (OVAR) is proposed and evaluated for metals processing. The use of OVAR is motivated by the need of hot air at a temperature below 1000K. It is well-accepted that the dust deposition will be a major challenge for implementation of OVAR 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 OVAR 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 (100µm & 200µm) on the inner surface of a pore. However, the effect of a non-uniform layer of dust deposition along the flow direction remains a question. The thickness of dust layer is more detrimental in view of substantial rise of absorber or air temperature and thus, the sustainability of OVAR needs to be addressed. The presented details are encouraging, 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.