Analysis of solar air heater performance in transient condition with various broken V-apex gap

Abstract

This article presents the numerical investigation of broken V-apex gap rib roughened solar air heater using ANSYS Fluent 15.0 with SIMPLE algorithm and k-ϵ RNG turbulence model. It is noticed that the temperature of absorber plate towards the V-apex is very high which reduce the heat transfer from heated plate to air in this region. For thermal performance enhancement in V-apex region, a new roughness parameter apex gap ratio (g'/e) ranging from 1 to 4 is introduced with the Reynolds number range 3000 to 18000. It is observed that broken V-apex gap ribs guide the secondary flow to pass through the apex of V-limb so that the temperature of absorber plate in that region reduces as a result of transferring heat to air. For the present study, the Nusselt number (Nu) and friction factor (f) is enhanced by 192% and 109% than smooth duct respectively. The maximum performance ratio parameter is found to be 2.315 at apex gap ratio of 3.