6824

6366

كارشناسي ارشد

تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1390

سيزده، 117ص.: مصور، جدول، نمودار

ص.ع.به فارسي و انگليسي

احمد صداقت، محمد علي اخوان بهابادي

ابراهيم شيراني

13/4/91

علي اكبر عالم رجبي، محمدرضا سليم پور

1396/09/14

كتابنامه

مكانيك

مهندسي مكانيك

ID6366

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Experimental Study on Heat Transfer and Pressure Drop of Nanofluid Flow inside Horizontal Coiled Wire Inserted Tubes under Constant Wall Temperature Condition Ali Akbar Shamshiri aa shamshiri@me iut ac ir 2012 2 22 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Ahmad Sedaghat sedaghat@cc iut ac irSupervisor Mohamd Ali Akhavan Bahabadi akhavan@ut ac irABSTRACTIn this work an experimental study is carried out to investigate the effect of adding MWCNT nanoparticles tothe heat transfer oil on flow heat transfer and pressure drop characteristics Thanks to many studies performed inrecent two decays on nanofluids Although usage of nanofluids heat transfer is in preliminary stages it isnecessary to understand mechanisms of enhancing in heat transfer in these studies Another technique usuallyhave been used for increasing in heat transfer is use of inserted devices such as wire coils in tubes They showseveral advantages in relation to other enhancement techniques such as Low cost and Easy installation andremoval Here the experimental works are carried out for pure base oil and nanofluids flow inside plain tubeand wire coil inserted tubes The wall temperature was maintained constant throughout this study and fluid flowis either laminar flow or low Reynolds number turbulent flow To provide constant wall temperature the entiretest section is surrounded by saturated water vapor The fluid flow in the tubes is considered hydrodynamicallydeveloped but thermally is in developing stage Heat transfer oil is HT B and nanoparticles are of MWCNTtype The heat transfer oil with the nanoparticles with the weight concentrations of 0 1 0 2 and 0 4 areconsidered as the working fluid The experimental study was carried out on six test sections including a circulartube with 1500 mm length 14 5 mm inner diameter and 15 6 mm outer diameter and five wire coils fitted in theplain tube within a geometrical range of helical pitch 1 12 p d 2 79 and wire diameter 0 069 e d 0 097 Base fluid and nanofluids characteristics like density viscosity thermal conductivity coefficient and specificheat capacity have been measured by means of accurate apparatuses The experimental measurements showedthat adding nanoparticles to the base fluid would lead to the increase in density thermal conductivity andviscosity of the base liquid but specific heat capacity decreases as nanoparticle concentration increases Themaximum increasing of the value of thermal conductivity up to 15 3 is achieved for nanofluid with the highestconcentration The experimental results of the convective heat transfer of flow inside plain tube and wire coilinserted tubes showed that by increasing the flow rate and nanoparticles concentration the convective heattransfer coefficient is increased The maximum enhancement of convective heat transfer coefficient of up to73 and 1014 are obtained for the nanofluid flow with 0 4 wt concentration for plain tube and wire coilinserted tube respectively On the other hand results obtained for pressure drop in plain tube and wire coil inserted tubes showed that thepressure drop was enhanced by increasing the flow rate and nanoparticles concentration Furthermore theperformance evaluation of the two enhanced heat transfer techniques studied in this investigation showed thatdilute nanofluids have better efficiency Key Wordsnanofluid heat transfer pressure drop constant temperature and wire coil inserts

احمد صداقت، محمد علي اخوان بهابادي

ابراهيم شيراني

علي اكبر عالم رجبي، محمدرضا سليم پور