CFD study for enhancement of heat transfer and flow characteristics of circular tube heat exchanger using Y-shaped insert

Abstract

The aim of present study is to investigate the enhancement of heat transfer and fluid flow characteristics using Y-shaped insert inside circular tube heat exchanger. The RNG k-ε turbulence model is used with variable geometrical parameter as Perforation Index (PI) of four values, PI = 0%, 10%, 20%, 30%, where Reynolds number (Re) ranges from 3000 to 21000, utilizing air as working fluid. Higher friction factor is obtained for higher PI due to turbulence created in the core region while for lower PI friction factor is lower and higher heat transfer is obtained. The highest heat transfer and Thermal Performance Factor (TPF) are obtained as 5.05 times and 2.88 times over smooth tube for non-perforated insert case at Re = 3000. Three Correlations for non-perforated case, with highest and lowest deviation of ± 4% & ±3% and three correlations for perforated case with highest and lowest deviation of ± 6% & ±2% have been developed for TPF, Nu and friction factor (f).