6089

5698

كارشناسي ارشد

تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1390

هشت،82ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

احمد صابونچي

محمدبهشاد شفيعي

3/5/90

احمد صداقت، محمدرضا سليم پور

1396/08/20

كتابنامه

مهندسي مكانيك

ID5698

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Experimental Study of Boiling Heat Transfer on High Temperature Cylindrical Silver in Nanofluid Hamed habibi khoshmehr h habibikhoshmehr@me iut ac ir 3 may 2011 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor A Sabunchi ahmadsub@cc iut ac ir AbstractIntense heat transfer is one of the paramount requirements necessities in many commonplace technologiesused in industries that can only be fulfilled through phase change of cooling fluid Most engineering systemssuch as power plants deal with pertinent boiling issues Hence many techniques to ameliorate boiling heattransfer have been presented and studied Thanks to recent advances in nanotechnology a new generation offluids nanofluids have come to existence Nanofluids can increase heat transfer rate compared withconventional fluids like water ethylene glycol and oil Therefore boiling characteristics must be taken intoaccount when using them as cooling fluids It is of significant importance to know nanofluids behavior undersuch circumstances to avoid corollaries that may negatively affect their cooling properties Given theaforementioned reasons the scrutiny of boiling heat transfer characteristics of nanofluids is of top priority atthis stage To this end the present experimental study aims to investigate the film boiling heat transfer onhigh temperature cylindrical silver 10 mm in diameter and 100 mm in length in nanofluid and water In thepresent study the temperature history in the center of cylinder is accurately recorded Heat transfer rate fromcylinder to fluid is calculated Inverse heat transfer is used with the hypothesis of isotherm cylinder Thehypothesis was investigated using theoretical and experimental data and the results verified the hypothesis Two cylindrical silvers with different surfaces roughnesses were used to investigate the effect of roughnesson nanofluid boiling heat transfer The surface roughnesses were measured by AFM yields 129 nm and 690nm for smooth and rough surfaces respectively The results gains suggested that a minimal differences insurface roughness leads to a substantial differences in quenching time of cylinders In this study CNT water C water Ag water and Fe3O4 water nanofluids were utilized An almost all cases heat transfer rate waslower compared with the deionized water This phenomenon is determined by particles material particlesdeposition on boiling surface surfactant and concentration of nanofluids In order to investigate particledeposition on boiling surface before and after CNT nanofluid tests SEM photos were taken from boilingsurface In Ferro fluid the effect of magnet field on boiling heat transfer rate was surveyed The distributionof magnet field was then simulated by Femm software and it s pertinent the particle motion was monitoredby PIV Results indicated a considerable increase in boiling heat transfer Keywords Boiling Nanofluid Roughness CNT water magnet field

احمد صابونچي

محمدبهشاد شفيعي

احمد صداقت، محمدرضا سليم پور