Review of development of artificial roughness in solar air heater and performance evaluation of different orientations for double arc rib roughness

Concept of artificial roughness on plain surface is an important technique to enhance heat transfer rate of air flowing in solar air heater. Over the years different rib geometries have been designed to investigate heat transfer and friction characteristics of solar air heater. In this paper an attempt is made to review development of different rib geometries employed for creating artificial roughness. Heat transfer and friction factor correlations developed by various investigators are presented. Performance evaluation for different orientations of double arc rib roughness is presented.