Numerical Investigation of Thermo-Hydraulic Characteristics of Non-Uniform Transverse Rib Roughened Solar Heater

A 3-D computational fluid dynamics (CFD) investigation on heat transfer and fluid flow of solar air heater duct roughened with transverse rib of non-uniform cross-section of square wave profile has been carried out using ANSYS Academic Research CFD 15.0. For comparison, transverse rib of uniform square and circular cross-section has also been investigated. Relative roughness pitch and relative roughness width of rib roughness have been taken as 10 and 85 respectively. Relative roughness height and Reynolds number were varied from 0.015–0.043 and 3000–15 000, respectively. The present CFD methodology has been validated with the experimental results. The maximum augmentation in Nusselt number over that of smooth duct was 2.2 and the corresponding enhancement of friction factor was 3.4 times.