7258

6764

كارشناسي ارشد

تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1391

ده، 92ص: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

مرتضوي

احمدرضا پيشه ور

21/8/91

محسن ثقفيان، محسن دوازده امامي

1396/09/21

كتابنامه

مكانيك

مهندسي مكانيك

ID6764

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

1AbstractIn this paper the time dependent interactions between two viscous deformable drops that move under effectof buoyancy force are simulated numerically in three dimensions and the effects of dimensionless parameterson film drainage are studied Drops have different sizes so diameter of leading drop is half the diameter oftrailing drop The Navier Stokes equations are solved with a finite difference front tracking method Bondnumber is considered to be large enough in order that drops can deform significantly Importantdimensionless numbers used here are Bond Bo number Morton Mo number Reynolds number Re viscosity ratio and density ratio The results obtained by Manga and Stone 1993 in the zeroReynolds number limit show that there are three methods for thin film drainage between two drops 1 Rapid drainage in which the thinnest region of the film is on the axis of symmetry2 Uniform drainage in which the film has a nearly constant thickness3 Dimple formationThe kind of fluid drainage that occurs between two drops depends on two dimensionless numbers which areBond number and viscosity ratio But the main factor in this issue is Bond number and for moderate Bondnumbers viscosity ratio may be effective For all Bond numbers the drainage begins with the first method rapid drainage In this case the thinnest area of film is on the symmetry axis and the faster drainage occurs When the distance between drops decreases as time proceeds drainage method changes to second and thenthird method In a small Bond number drainage is carried out only with first method For large Bondnumbers drainage changes to the second mode Only for moderate Bond numbers all of the three kinds ofmethods can occur The Reynolds number affects collision of drops more for small Bond numbers morerigid drops and the separation distance that are obtained from simulations do not agree whit the zeroReynolds number limit for small Bond numbers Also the collision of two drops at the beginning of themovement is influenced by the Reynolds number The thickness of the thin film decreases faster for lowBond numbers 1 compared to medium Bond numbers 10 For a moderate Bond number dimpleformation for 1 occurs earlier Also For greater viscosity ratio 5 dimple formation occurs at alarger distance from the axis of symmetry For all range of Reynolds numbers rising velocity and thusReynolds number decreases with increasing the viscosity ratio and increases with increasing of Bond number Also drop deformation increases with increasing Reynolds number Finally the motion of four drops is simulated and the effect of increasing the number of drops on the dropsmotion is studied Key WordsCollision interaction drops gravity buoyancy force three dimensional

مرتضوي

احمدرضا پيشه ور

محسن ثقفيان، محسن دوازده امامي