4242

4013

كارشناسي ارشد

تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1387

ده، 91، [II] ص.: مصور، نمودار

ص. ع. به فارسي و انگليسي

ابراهيم شيراني

احمدرضا پيشه ور

23/7/1387

محسن ثقفيان، احمد رضا صداقت

1396/03/07

كتابنامه

مكانيك

مهندسي مكانيك

ID4013

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

ABSTRACTThe aims of this thesis are numerical simulation of movement and deformation of a droplet onsurfaces and study of surface tension models Droplets have many applications in science andtechnology One of these applications is in the cathode of a PEM Fuel Cell where water dropletsare produced In PEMFCs water management is a significant issue because excessive dropletwater cause low efficiency Thus a small electric fan is used to sweep the produced droplets For numerical simulating of droplets flow we used a computer code which can model the interfacefor three dimensional cases Navier Stocks equations are solved based on finite volume techniqueusing fractional step method and multi grid in a staggered Cartesian mesh The Interface ismodeled utilizing PLIC VOF The results of present thesis are in four sections First four different methods are used to model thesurface tension force A stationary drop is simulated and the pressure contours and parasitic currents are considered Parasitic currents are produced by applying surface tension force ininterfacial problems with Eulerian approach Results are compared with previous studies and ithas been shown that the SGIP model is superior over the other models Thus we used this surfacetension model for our proceeding studies Then by smoothing initial shape of the drop the parasiticcurrents reduced and the results are improved For the next step the parasitic currents and theeffect of various parameters such as mesh size drop size viscosity and density on parasiticcurrents for a stationary drop are studied Then the impact of a droplet on an inclined surface isstudied For this purpose a dynamic contact angle model is applied for a case which experimentaland numerical results are available The comparison is made with such cases After validating theresults the effect of inclination and the impact velocity is studied Then movement of a droplet on asurface caused by fluid flow is simulated After mesh study effect of various parameters such as droplet size contact angle viscosity and density ratio and the fluid flow velocity are studied bycomparing the droplet shapes and the velocity of the droplet center during the time for thirteensimulated cases Finally we obtained a relationship between droplet velocity and the Webernumber

ابراهيم شيراني

احمدرضا پيشه ور

محسن ثقفيان، احمد رضا صداقت