پديد آورنده :
عليدوست، محمدعلي
عنوان :
مدل سازي عددي تغيير فرم قطره در ميدان الكتريكي ساكن با در نظرگرفتن اثر حركت بارها بر روي سطح آزاد
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
تبديل انرژي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك
صفحه شمار :
شانزده، 87ص.: مصور، جدول، نمودار
يادداشت :
ص.ع. به فارسي و انگليسي
استاد راهنما :
احمدرضا پيشه ور
استاد مشاور :
سعيد مرتضوي
توصيفگر ها :
جريان دوفازي , الكتروهيدروديناميك , الكترواستاتيك , معادله بقاي ﴿انتقال﴾بار الكتريكي , سطح مبنا ﴿لول ست﴾ , سيال مجازي
تاريخ نمايه سازي :
6/3/94
استاد داور :
ابراهيم شيراني، محسن ثقفيان
تاريخ ورود اطلاعات :
1396/10/02
چكيده فارسي :
شانزده چكيده مسئله تغيير شكل قطره شناور در ميـدان الكتريكـي پديـدها اسـت كـه ـ ـ ـ ـ ـ تاكنون به طور گسترده مـورد مطالعـه قـرار گرفتـه اسـت و كاربردهـا ـ ـ ـ ـ ـ ـ مختلفي دارد در پژوهش حاضر رفتار ديناميكي قطره با در نظـر گـرفتن ـ ـ مدل ديناميكي بار الكتريكي رو سطح مشترك بين قطره و سيال بيرونـياش ـ تحت اثر ميدان الكتريكي يكنواخت به صورت عدد مـدل مـيشـود و نتـايج ـ ــ ـ حاصل از آن با نتايج عدد و آزمايشگاهي ديگر مقالههـا اعتبـار سـنجي ـ ـ ـ ميگردد لازم به ذكر است قطره و سيال بيروني هر دو از نوع سـيالهـا ـ ـ
چكيده انگليسي :
120 Numerical Simulation of Drop Deformation in a DC Field by Considering Surface Charge Transport Equation Mohammad Ali Alidoost M Alidoost@me iut ac ir Date of Submission 2015 03 14 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Ahmad Reza Pishevar apishe@cc iut ac irAbstractThe drop deformation problem in the electric field is an issue that has been widely studied and has variousapplications This subject is one of the subsets of physical phenomena called Electro hydrodynamics EHD In the present study the dynamic behavior of the drop is modeled numerically by considering thedynamic model of electric charges on the interface between the drop and its outer fluid under the effect of auniform DC electric field The results given from this work are validated by both numerical andexperimental results of other articles It should be noted that both of the drop and its exterior fluid havebeen considered as leaky dielectric fluids and their low conductivities lead to constitution of a thin layer ofthe electric charges near the interface thus with solving the charge conservation transfer equation on theinterface the effect of conduction and convection of charges will be handled In fact surface convection ofcharges on the interface dilation of the interface and transportation of electric charges due to theconduction across the interface electromigration will be modeled In this work incompressible andNewtonian fluid motion equations Navier Stokes are solved in a Cartesian staggered grid by using theprojection method Moreover the interface followed by the level set method LSM in an implicit way andthe Ghost fluid method GFM is used for modeling the jump boundary condition at the interface As aconsequence jump conditions are calculated exactly without considering any thickness for the interface bythe GFM method Also stresses boundary conditions on the interface are the connections that link electricforces to the hydrodynamic part of problem To ensure the accuracy of numerical method presented here asimple problem is considered for each of the terms of the conservation equation to simulate both surfaceconvection of charges on the interface and dilation of the interface The results of this part show that theperoposed numerical method for solving the terms of charge conservation equation and the physicalmeaning of those terms supported each other Finally small drop deformation is investigated with changingvarious and effective parameters conductivity ratio permittivity ratio capillary number and dimensionlesselectric relaxation time It should be noted that for solving the charge transport equation the relaxationtime of electric phenomena must be equal or larger than hydrodynamic time scale In addition large dropdeformation is studied in different ranges of capillary number The results of the prolate deformation in thiswork are in good agreement with previous works however the oblate deformation results representnoticeable diffrences because of decreasing in the intensity of the velocity field by considering the effects ofelectric charges at the interface Additionaly for satisfying the condition of the electric relaxation time thesize of the drop is considered smaller than the same works therefore for the case used in this project thedeformation of the drop decrease more Keywords Electrohydrodynamics Electrostatics Leaky dielectric Transport equation Level setmethod Ghost fluid method
استاد راهنما :
احمدرضا پيشه ور
استاد مشاور :
سعيد مرتضوي
استاد داور :
ابراهيم شيراني، محسن ثقفيان
