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Abstract

The present work shows the effect of insertion converge-diverge conical-nozzle turbulators fitted with triangle fins inside a heated circular pipe on turbulent flow heat transfer, friction and overall performance index. The study is performed experimentally for turbulent flow system with use of air as a working fluid for a range of Reynolds number between 10000 to 50000. The conical nozzles integrated with triangle fins are utilized as turbulators to generate more complex mixing flow along the pipe wall. The plane conical nozzles turbulators are used for three various pitch ratios (Pr=1.0,1.5 and 2), and those fitted with triangle fins are tested at pitch ratio Pr=1.0 with two various area ratios of 0.064 and 0.149 respectively. The heat transfer of conical turbulators integrated with triangle fins is enhanced by 274% as compared with plain pipe and 55% as compared with inserted conical nozzle turbulators alone for the larger area ratio (Ar =0.149). In the addition, the Conical nozzle turbulators fitted with triangle fins give optimum overall thermal performance as compared with unfinned conical nozzle turbulators and plane tube.