Study of hydrodynamic and thermal parameters of the air flow of a solar air heating collector

Abstract

In this study, the thermal and hydraulic characteristics of the air flow over the metal shavings of the absorber of a solar air heating collector were analyzed. During the study, formulas were derived for calculating the temperature and hydrodynamic parameters of the flow. The air flow temperature, boundary layer thickness, local friction stress on the chip surface and other important parameters were determined. Calculations were performed for various flow rates and Reynolds numbers. The results obtained made it possible to evaluate the influence of metal shavings on the characteristics of the air flow. It was shown that the thickness of the boundary layer decreases with increasing Reynolds number, which is consistent with hydrodynamic theory. A comparison was also made of the thermal resistance for a smooth surface and a surface with metal shavings. The results showed that the use of metal chips could reduce the thermal resistance, which could be beneficial for improving the heat transfer efficiency in solar air heating collectors.

Keywords

• hydrodynamic
• air flow
• thermal energy balance
• thermal conductivity
• solar air heater collector
• sunlight flow
• solar energy
• heat loss
• optimal turbulent regime