Heat Transfer and Frictions in the Rectangular Divergent Channel with Ribs on One Wall

Abstract

An investigation of ribbed divergent channel was undertaken to determine the effect of rib pitch to height ratio on total friction factor and heat transfer results in the fully developed regime. The ribbed divergent rectangular channel with the channel exit hydraulic diameter (D ho ) to inlet channel hydraulic diameter (D hi ) ratio of 1.16 with wall inclination angle of 0.72 deg, at which the ratios (p/e) of 6,10, and 14 are considered. The ribbed straight channel of D ho /D hi =1.0 were also used. The ribbed divergent wall is manufactured with a fixed rib height (e) of 10 mm and the ratio of rib spacing (p) to height 6, 10, and 14. The measurement was run with range of Reynolds numbers from 24,000 to 84,000. The comparison shows that the ratio of p/e=6 has the greatest thermal performance in the divergent channel under two constraints; identical mass flow rate and identical pressure drop.