7409

6915

كارشناسي ارشد

تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1391

نه، 88ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

سعيد مرتضوي

احمدرضا پيشه ور

27/9/91

محمود اشرفي زاده، احمد سوهانكار اصفهاني

1396/09/22

كتابنامه

مكانيك

مهندسي مكانيك

ID6915

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Numerical Simulation of Drops in a Shear Flow under Gravity Seyed Amin Razavieh sa razavieh@me iut ac ir Date of Submission 16 09 2012 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Saeed Mortazavi saeedm@cc iut ac ir Abstract The motion of drops suspended in another fluid has a wide variety of practical applications These include the flow of oil and water through pipelines the recovery of oil through porous rock and polymer processing The lateral migration of deformable particles in shear flows has been the subject of many investigations The motion of deformable drops suspended in a linear shear flow at non zero Reynolds numbers is studied by numerical simulations in two dimensions In this study the full Navier Stokes equations are solved by a finite difference front tracking method A drop migrates to an equilibrium position in a horizontal shear flow In this part effects of non dimensional parameters such as Particle Reynolds number Gravity Reynolds number density ratio viscosity ratio drop size and capillary number are investigated It was found that a drop which in the absence of shear would settle to the bottom of the channel is actually lifted and obtains an equilibrium position away from the channel floor when the Reynolds number is large enough It is expected that at very high shear rates drops with high density ratios would suspend in the flow As the capillary number the Reynolds number viscosity ratio or drop size decreases the equilibrium position moves closer to bottom of channel The drop velocity is observed to increase with increasing capillary number viscosity ratio and Reynolds number The drops are more deformed with increasing the capillary number To validate the present calculations some typical results are compared with the available predictions which confirm that the present approach is reliable in predicting the drop migration In second part we investigated the effects of non dimensional parameters such as bulk Reynolds number gravity Reynolds number and density ratio on the motion of suspension of buoyant drops in a shear flow It is observed that under some conditions flow experiences solid like or fluid like behavior and the transition between these two behaviors are numerically investigated As the bulk Reynolds number decreases or the gravity Reynolds number and density ratio increases average equilibrium position of drops moves closer to bottom of channel It is observed that average drops density distribution in upper half of channel increases by increasing the bulk Reynolds number or decreasing the gravity Reynolds number and density ratio The fluctuation energy of the flow across the channel suspension temperature was also computed for different flow conditions It is of interest because it is closely related to the diffusivity of suspension The fluctuation energy is lowest near the channel floor where flow experiences solid like behavior and the interaction between drops is weak It increases as one moves away from the channel floor and becomes maximum in the region that flow experiences fluid like behavior It vanishes in the wall regions where no drops are present The fluctuation energy decreases with Capillary number since the interaction between drops gets weaker as the Capillary number is raised Keywords Equilibrium position Shear flow Reynolds number Gravity Reynolds number Capillary number Density ratio Viscosity ratio Suspension of buoyant drops Fluctuation energy

سعيد مرتضوي

احمدرضا پيشه ور

محمود اشرفي زاده، احمد سوهانكار اصفهاني