CFD analysis of thermal performance in isosceles right triangle rib roughness on the absorber plate solar air heater

Abstract

Objective: This paper provides analytical investigation of flow and roughness parameters on average heat transfer and flow friction characteristics of an artificial roughness solar air heater having isosceles right triangle ribs on the absorber plate. Methods/Statistical Analysis: Artificial roughness having isosceles right triangle geometry is developed for breaking laminar sub-layer. In CFD simulation different parameter like Reynolds no-3593 to 15000, duct aspect ratio=5:1, relative roughness pitch (P/e) i.e. 3.33-40(12 values) and relative roughness height (e/D) i.e. 0.015-0.045(3 values) taken. Findings: In all cases the average Nusselt number tends to increase as Reynolds number increases. The average friction factor has been found to be 3.45 times over the smooth duct. It has been observed that the average friction factor tends to decrease as the Reynolds number increases. Increment in Thermal performance obtained for Maximum thermohydraulic performance is obtained for relative roughness pitch of 5 and relative roughness height 0.045. Applications/Improvements: The applications of solar air heaters are space heating and drying. Recent time solar air heater is very important in rolling agriculture purpose, heating and cooling of the room and industrial applications.