Computational Analysis of Bulb-Shape Ribs Roughened Absorber Plate of Solar Air Heater

Abstract

Abstract In this work, thermo-hydrodynamic simulation was carried out for bulb-shaped ribs roughened absorbing surface of solar air heater at 1kW/m2 for and various Reynolds numbers. Primarily, sensitivity analysis of turbulent models was carried for flow over the surface, and it observed that RNG k-\(\epsilon\) model results is more closed with respect to Dittus-Boelter equation. After selection of appropriate turbulence model, simulations were carried out on a bulb-shape rib and other shapes of roughened ribs surface. This study reveals that absorber bulb shaped ribs roughened surface has at least two times more performance improvement factor (Nu/f) as compared to the other ribbed shape roughened surface. Eventually, the Nusselt number and Coefficient friction for bulb shaped ribs roughened surface were correlated in terms of Reynolds number (Re) and relative roughness (β). These correlations are substantial for designing solar air heating systems for bulb-shaped ribs roughened as absorbing surface.