9505

8787

كارشناسي ارشد

مكانيك- تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1393

يازده،81ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محسن ثقفيان

محسن دوازده امامي

5/11/93

محمدرضا سليم پور، مهدي نيلي احمدآبادي

مهندسي مكانيك

ID8787

فھرست مطالب عنوان صفحه فھرست مطالب ھشت چكيده 1 فصل اول مقدمه ا 1 1 كاربردھ 3 دل ھاي م ان و روش اي جري مھ 1 2 رژي سازي 5 ان ازي جري دل س 1 3 م ھا 6 رو و اي ميك ان ھ ددي جري ازي ع بيه س 1 4 ش نانو 6 هي اي مرتب رش دم زش و پ ادالت لغ 1 5 مع اول 6 فصل دوم هيدروديناميك مغناطيسي و كاربردها آن ه 2 1 مقدم 9 ي درويناميك مغناطيس 2 2 ھي چيست 01 دروديناميك هاي از ھي 2 3 تاريخچ مغناطيسي 21 وانين 2 4 ق الكتروديناميك 31 ر اكم ب ادالت ح 2 5 مع ك الكترودينامي 51 روي ي و ني دان الكتريك 2 5 1 مي لورنتز 61

77 Numerical Simulation of Natural Mixed and Forced Convection in Microchannels under the Effect of a Magnetic Field Mehdi Moslehi m moslehi@me iut ac ir Date of Submission 2014 09 8 Department of Mechanical Engineering Isfahan University of Technology Isfahan Iran Degree M Sc Language Farsi Supervisor Mohsen saghafian saghafian@cc iut ac ir Abstract Magnetohydrodynamic MHD is a new and important branch of fluid dynamics It focuses on fluid flow and magnetic field interaction Any movement of an electrically conducting fluid in the presence of a magnetic field leads to induce a body force to the fluid flow This force can change hydrodynamic and thermal behaviors of the flow In this study natural mixed and forced convection of a laminar flow in microchannels under the effect of a uniform transverse magnetic field are investigated numerically In the case of natural convection steady and unsteady behaviors are studied It is revealed that magnetic force decreases mass flow rate It increases temperature along the channel walls and causes to an increase in cross section one Nusselt number also decreases with magnetic field Mass flow rate and maximum wall temperature as a function of time detect at least one overshoot The overshoot decreases with an increase in magnetic field strength Moreover it is observed that the time at which steady state condition is attained has insignificant change with magnetic force Mixed convection in a vertical microchannel is investigated In this case increasing magnetic force leads to a decrease in maximum velocity value and causes to an increase in velocity gradient near the channel walls Temperature increases slightly with Lorentz force and hence Nusselt number increase In higher considered Knudsen number magnetic force effect on the fluid flow and thermal characteristic increases In addition with an increase in buoyancy force magnetic field influence decreases Forced convection in a horizontal channel under the effect of magnetic field also is studied This field leads to a decrease in the maximum velocity value and hence causes to a significant increase in velocity gradient close the channel walls This effect causes to a significant increase in friction factor coefficient Nusselt number increase slightly with an increase in magnetic force In addition increasing magnetic force leads to increase on the fully developed temperature but it has insignificant effect on the channel entrance region It is very interested to note that in all cases of natural mixed and forced convection magnetic force influence on the fluid flow behavior is almost more significant with respect to thermal one Keywords MHD Slip flow Transient Microchannels Unsteady Natural convection Mixed convection Forced convection

محسن ثقفيان

محسن دوازده امامي

محمدرضا سليم پور، مهدي نيلي احمدآبادي