Paper Title
Study of Heat Transfer and Friction Factor in Rectangular Duct: A Review

Abstract
This paper presents the study of effect of different roughness geometries used by some investigators over last few years on the heat transfer and friction factor in solar air heater. The presence of roughness geometry leads to increment in the heat transfer coefficient as compared to smooth plate. This increase in the heat transfer coefficient results in increase of Nusselt number that is very essential for the improvement of thermal efficiency. With the enhancement of heat transfer coefficient, there is always a rise in the friction factor. But the different roughness geometries do not affects the heat transfer and friction factor in the same manner. Therefore the study of variation in the heat transfer and friction factor for different roughness geometries is being present in this paper. Keywords - Heat Transfer, roughness geometry, friction factor, Nusselt number, Rectangular Duct