بررسي تجربي ضريب انتقال جرم فرآيند جذب گاز در نانو سيال Fe3O4/H2O

چكيده انگليسي :

80 Experimental Investigation of Mass Transfer Coefficient of Gas Absorption in the Fe3O4 H2O Nanofluid Elahe Fadaei Tehrani e fadaeitehrani@ce iut ac ir 27 February 2012 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Mohsen Nasr Esfahany mnasr@cc iut ac ir Nasrin Etesami netesami@cc iut ac irAbstract Nano uids has been attracting considerable attention worldwide recently because nano uids can be used toenhance the heat and mass transfer and can solve the problems of sedimentation corrosion and clogging that areassociated by millimeter or micrometer sized particles Many studies have conducted to study the thermalconductivity and heat transfer enhancement in nano uids but little studies for the mass transfer characteristics ofnano uids have found in the literature Therefore effects of nanoparticles have been overlooked in mass transferin the existing literature and more research must be done to determine the effects of nanoparticles on the masstransfer Gas absorption is a mass transfer operation in which a gas mixture is contacted with a liquid for thepurpose of preferentially dissolving one or more components of the gas mixture and to provide a solution of themin the liquid Unfortunately the absorption rate of gases into a liquid is limited The absorption rate of solublegases into a liquid in the presence of a third dispersed phase e g droplets solid particles can signi cantly beimproved when the solubility gases in the particles is higher than that in the continuous liquid phase In thepresent study the effects of Fe3O4 water nanofluids with concentrations of 0 001 0 005 0 01 0 025 and0 05 by volume on the CO2 absorption have been investigated experimentally These nanofluids have beenobtained by diluting initial nanofluid with 7 of nanoparticles Measurements of viscosity in nanofluids besidesmass transfer coefficients have also been carried out by capillary viscometer A glass tube with inner diameter of1 millimeter has been connected to a liquid container For meassuring mass transfer coefficient vertical plastictubes of 6 8 10 and 14 mm inner diameter were used in the experiments as falling film columns All these tubeshave been connected to a perfectly vertical base In these tubes the rising bubble contacted with falling liquid andthe amount of CO2 absorption has been measured The Simple design of the apparatus leaded to easymeasurement and the cost reduction Reynolds number was being changed in the range of 450 2100 by changingtube diameter from 6 14 mm In order to verify accuracy of experimental set up and procedure experimentalSherwood number were compared with theoretical values which were calculated by existing correlations Experimental results were in reasonable agreement with theoretical values According to the experimentalmesurment of mass transfer coefficient for nanofluids 0 001 and 0 005 mass transfer coefficient decreasedinto the base fluid in all Reynolds numbers It can be seen that mass transfer coefficient was enhanced atReynolds numbers higher than 1250 in the nanofluid of 0 01 Nanofluid with 0 025 of nanoparticles enhancedmass transfer coefficient for Reynolds number higher than 750 But mass transfer coefficient was enhanced in allReynolds numbers studied here in the nanofluid of 0 05 Experimental results of nanofluid viscosity showed anincrease trend with increasing nanofluid concentration Considerable differences are observed between measuredvalues and calculated values by existing equations Keywords Gas absorption process mass transfer coefficient Sherwood number falling film column nanofluid viscosity

فدايي تهراني، الهه

بررسي تجربي ضريب انتقال جرم فرآيند جذب گاز در نانو سيال Fe3O4/H2O

عدد شروود , ستون فيلم ريزان , ويسكوزيته