8671

8052

كارشناسي ارشد

تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1392

شانزده،156ص.: مصور،جدول،نمودار(رنگي)

ص.ع.به فارسي و انگليسي

احمد سوهانكار

مهدي نيلي

19/1/93

احمدرضا پيشه ور، محمدرضا سليم پور

مهندسي مكانيك

ID8052

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Numerical investigation of nano uid forced convection heat transfer in rotating convergent divergent U shaped mini micro channels with ribs Mokhtar Kanikzadeh m kanikzadeh@me iut ac ir Date of Submission 2014 01 20 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Ahmad Sohankar asohankar@cc iut ac irAbstractThe impact of the forced convection flow of the nanofluids on the thermal performance of the differentribbed smooth rotating U type cooling channels is investigated in this work The U type channel rotates aboutthe axis perpendicular to the main flow direction The 45 angled ribs are attached to the leading and trailingwalls in parallel for ribbed channels The nanofluids are provided by the inclusion of the nanoparticles of TiO2and Al2O3 in water as the base fluid namely water Al2O3 and water TiO2 nanofluids mixtures The numericalsimulations are performed for three different geometries including macro micro and minichannels In order tounderstand the effects of the ribs on the fluid flow and heat transfer in the channel the flow of nanofluids in thesame channel with no ribs smooth channel is also simulated To improve the heat transfer enhancement of theemployed macrochannel parallel arrangements of the micro mini channels are also evaluated Also theconvergent divergent U type minichannel is investigated Three dimensional laminar and turbulent simulationsare carried out based on the employed geometries For the cases with turbulent flow and heat transfer Re 5000 20000 numerical simulations are performed by using Reynolds Averaged Navier Stokes equations RANS Inorder to calculate turbulent viscosity different one and two equation turbulence models are tested and finally aRNG K turbulence model is employed To show the effectiveness of the rib and nanofluids the thermalperformance factor is used to evaluate the amount of heat transfer enhancement relative to power consumed The combinatorial effects of the ribs and nanofluids on the results and also the contribution of each one in theheat transfer enhancement for the different geometries are determined It is found that the inclusion of thenanoparticles into the base fluid is provided a considerable augmentation on the heat transfer that clearlyincreases with an increase of the particle concentration and Reynolds numbers The results also show using ribson the walls of the macrochannel improve heat transfer enhancement A comparison between the results ofdifferent type of channels employed show that the fluid flow through the minichannels provides the bestperformance on heat transfer augmentation KeywordsNanofluids U shaped channels smooth and ribbed micro minichannels heat sink heattransfer enhancement thermal performance numerical simulation convergent divergent turbulent flow

احمد سوهانكار

مهدي نيلي

احمدرضا پيشه ور، محمدرضا سليم پور