NUMERICAL ANALYSIS OF HEAT TRANSFER ENHANCEMENT IN CONICAL-NOZZLE TURBULATORS INSERTED TUBE

Year 2018, Volume: 13 Issue: 1, 7 - 17, 21.01.2018

Sibel Güneş Toygun Dağdevir Orhan Keklikcioğlu Veysel Özceyhan

Abstract

     This
numerical work is associated with the investigation of the effect of turbulator
arrangement (diverging and converging) on heat transfer enhancement in conical
nozzle turbulators inserted circular tube. Three different pitch ratios
(PR=2.5, 5 and 7.5) were considered in the numerical analyses, using air as
test fluid. The numerical results of Nusselt number, friction factor and
thermal performance factor were introduced for the range of Reynolds numbers of
6000-24000. The obtained results showed that smaller pitch ratios provided more
heat transfer rate and pressure drop. As compared to converging nozzles,
diverging nozzles generated more effective turbulance/reverse flow, and thus
provided higher heat transfer and flow friction. Evidently, obtained results
revealed that the usage of nozzle-turbulators as a turbulence/reverse flow
generator has an important contribution on heat transfer improvement.

Keywords

Reverse Flow, Nozzle-Turbulator, Heat Transfer, Flow Friction, Nusselt Number

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