Thermo-hydraulic performance of a rectangular duct with staggered inclined discrete rib arrangement

Abstract

Artificial roughness in the form of ribs is a beneficial strategy to improve the thermal performance of solar air heaters (SAHs). In the present research work, experimental examinations have been conducted on heat transfer and friction characteristics in the rectangular channel, which is roughened through the inclined discrete ribs. The inclined ribs were discretized by creating gaps at the different positions (not inline) on trailing and leading edges in consecutive ribs The rib roughness has relative roughness pitch as 8.0, rib combination of relative gap position is varied from 0.3 & 0.1 to 0.3 & 0.4, and mass flow rate varies between 3000-14,000 and rib gap width as 1. The higher improvement in the Nusselt number and factor of friction coefficient is obtained to be 2.92 and 3.33 times respectively, as compared with that of the smooth duct. The higher thermo-hydraulic performance parameter (THPP) is obtained for the combination of relative gap position of 0.3 & 0.3.