Numerical investigation of solar air heater duct with square transverse and inclined ribs

Abstract

A numerical investigation has been carried out in order to investigate the effect of artificial roughness on heat transfer coefficient and pressure loss of air flow through an asymmetrically heated rectangular solar air heater duct with constant heat flux condition on absorber plate. Reynolds number is varied from 3000 to 15000. Artificial roughness in the form of transverse and inclined ribs is applied to the surface of the absorber plate. Heat transfer coefficient, friction factor and thermo-hydraulic performance parameter (THPP) are calculated for the range of roughness parameters; relative roughness pitch (P/e) from 11 to 25 at constant relative roughness height (e/D) of 0.8. RNG k- ε turbulence model has been selected for CFD simulation. Artificially roughened surface increased heat transfer coefficient at the expense of increased pressure loss of air flow through the duct.