7005

6547

كارشناسي ارشد

مهندسي شيمي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي شيمي

1390

سيزده، 91ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

مسعود حق شناس فرد، ارجمند مهرباني

محسن نصر اصفهاني

3/7/91

نسرين اعتصامي، طيبه بهزاد

1396/09/18

كتابنامه

مهندسي شيمي

مهندسي شيمي

ID6547

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

97 CFD Modeling of a Termosyphon Heat Pipe Phase Change Heat Transfer of Nanofluid Leila Asmaei Asmaei leila@yahoo com Department of Chemical Engineering Isfahan University of Technology Isfahan Iran Degree M Sc Language FarsiSupervisor Masoud Haghshenas Fard haghshenas@cc iut ac irAbstractOne of the most important industrial aims of researchers and engineers is energy efficiency and increasing yield Due to the unique features heat pipe has a special position in systems to optimize energy consumption andenergy recovery Heat pipe is an efficient appliance to transfer heat in a limited ambient One of the limitedfactors of heat transfer ability in pipes is the properties of working fluids In order to overcome this limitation thermo physical properties of the fluid can be improved One of the new ideas to increase the thermalconductivity constant of liquid is distribution of nanoparticles in the main fluid This new generation ofconductive fluids with nanoparticles are referred to as nanofluids The nanoparticles within the fluid change itsthermal conductivity viscosity and density So some researchers are trying to apply nanofluids to heat pipes forenhancing their heat transfer performance In this investigation computational fluid dynamic CFD was used tomodeling of fluid and two dimensional heat transfer with phase change in a heat pipe thermosyphon in whichdistilled water and nanoparticle were working fluids Modeling was done by the software fluent and desiredgeometry was made by gambit In the first stage copper oxide nanofluid at a concentration of wt in basicfluid of distilled water was used as the working fluid Modeling of two phase fluid was done with both the defaultmodel of the software and also coding procedure with considering the effects of non condensation gases Convection in thermosyphon and condensation and evaporation was simulated by calculations Temperaturedistribution and heat transfer coefficients in CFD were compared with the experimental results highcompatibility was achieved Results show that in the existence of nanofluids temperature distribution was moreuniform Also it was clear that by using nanofluid water copper oxide instead of distilled water in thermosyphonresults in increasing heat transfer coefficients For instance heat transfer coefficient of nanofluid evaporation inheat load of W was higher than distilled water The effect of the presence of non condensation gases wasstudied by changes in heat transfer coefficient of condensation These gases reduced the heat transfer coefficientof condensation to numbers lower than experimental values Also the effect of the presence of nanofluids on thetotal thermal resistance was investigated In equal input powers the reduction in total thermal resistance ofnanofluid was observed in comparison with distilled water Then in the second stage effect of kind andconcentration of nanofluids was investigated In order to study the effect of nanofluid modeling was done inconcentrations and wt By increase in nanofluid concentration from to percent increase of in heat transfer coefficients was observed Finally the copper oxide nanofluid was substituted with goldnanofluid wt and the new results are compared with copper oxide nanofluid results These results showsthat evaporation heat transfer coefficient of gold nanofluids was higher than copper oxide nanofluids which was more clear in higher input power Key Words Thermosyphon evaporation condensation computational fluid dynamic

مسعود حق شناس فرد، ارجمند مهرباني

محسن نصر اصفهاني

نسرين اعتصامي، طيبه بهزاد