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Abstract
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Nanofluidshaveacquiredcomprehensiveattentionduetotheirroleinenhancingtheefficiencyofthermalsystems.ThepresentstudyreportsafurtherenhancementinNusseltnumberalongwiththemodificationofflowsystemstructures,namely,theadditionofbutterflytubeinserts(BTI)withaninclinedangleof90°inatubeatconstantheatfluxconditions.ExperimentsareperformedtodetermineNusseltnumberandthefrictionfactorofAl2O3/waternanofluidupto2.5%nanoparticlevolumeconcentration(NVC)andintheReynoldsnumberrangeof750–8500.ResultsshowedthatbyusingBTI,nanofluidsfrictionfactorincreasedbyanaverage2.6%relativetotheplaintube.Also,NusseltnumberincreasedwithReynoldsandalongthetubeaxisforlaminarregime.Aconsiderableenhancementofabout345%intheNusseltwasobservedat0.027%NVCandRe=1500fortheflowinatubewithitsBTIrelativetoplaintube(PT).A2.5%increaseintheNVCdecreasedNusseltnumberfortheflowinatubewithBTI.Finally,twocorrelationsforthefrictionfactorandNusseltnumberofwaterandaluminananofluidinatubewithBTIbasedonthemeasuredexperimentalvaluesweredeveloped.
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