Evaluation of Roughened Duct with Similar Wideness Gap of Arc with Staggered Link and Comparison with Similar Rib Roughness Geometries

This paper introduces new roughness used in roughened duct and evaluates the effective performance for wideness gap of arc with staggered link geometry. The present new roughness geometry has parameters like obstacle pitch of rib P'/P as 0.4, relative wideness of arc gap g/e as 3, ratio of arc stumble link to rib diameter (r/e) as 3 and arc angle (α) as 30o , gaps on either side of full arc as a number (Ng) of 3, rib pitch with respect to rib height (P/e) as 10 and dimensionless number of Reynolds (Re) as range of 3500 -14000. Turbulence geometries such as similar wideness gap of arc with staggered link, continuous arc rib, arc with gap rib and arc with a gap with obstacle element for rib pitch with respect to rib height (P/e) as 10 were tested. Highest factor of friction coefficient and Nusselt number is obtained to be 3.94 and 1.99 respectively for similar wideness of arc gap with stamble link. Evaluation of THP of similar wideness arc gap with stamble link roughness is higher than existing arc shaped rib element for all values of dimensionless Reynolds number with limit as 3000 to 14000.