اطلاعیه برای دفاع پایان‌نامه کارشناسی ارشد در رشته مهندسی مکانیک گرایش تبدیل انرژی

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: اطلاعیه برای دفاع پایان‌نامه کارشناسی ارشد در رشته مهندسی مکانیک گرایش تبدیل انرژی

ارائه دهنده: Provider: Abbas Eini

اساتید راهنما: Supervisors: Amireh Nourbakhsh (Ph. D)

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Mohammad Saeed Aghighi- Fazlollah Eskandari Manjili

زمان و تاریخ ارائه: Time and date of presentation: February 16, 2021 , 16:00

مکان ارائه: Place of presentation:

چکیده: Abstract: The movement of bubbles on sloping surfaces such as sloping canals has numerous scientific and industrial applications. In the present study, a three-dimensional simulation of the transverse motion of a bubble inside a sloping channel in a Poissy flow in the presence of gravity is investigated. The Navier-Stokes equations, which include surface tension, are solved by finite difference / droplet tracking. The finite difference / droplet tracking method is based on writing a set of survival equations for the entire solution domain. Also, this combined method uses bubble tracking and capture techniques. In such a way that both phases behave in the form of a fluid with variable material properties. A regular fixed grid is used for fluid flow, but the interface between the two fluids is tracked by a separate grid with a lower dimension. By performing the simulations, we seek to investigate the effect of non-dimensional numbers such as capillary number, Reynolds number, landing number, geometric ratio, adhesion ratio and also the channel slope angle on the transverse motion of the bubble. Studies show that the bubble regardless of the initial position in which It is left in an equilibrium position between the central axis of the canal and its wall. The results show that the dimensionless number is suitable for investigating the effect of surface tension of the capillary number because the bubble deformation is highly dependent on the number without the capillary dimension. , With increasing capillary number, the axial velocity and also the bubble deformation increase and equilibrate in a position closer to the center of the channel. It has been observed that increasing the adhesion ratio increases the wall thrust (lubrication force) and as a result the bubble migration rate to The equilibrium position increases and equilibrates at a position closer to the center of the channel, the bubble deformation rate increases slightly, but at a constant capillary number the bubble deformation dependence on the adhesion ratio is very low.The effect of Reynolds dimensionless number showed that with increasing Reynolds number, the effect of adhesion and lubrication force decreased and then the final equilibrium position of the bubble moved away from the center and closer to the channel wall. Also, the effect of channel slope angle showed that with increasing angle The channel, the bubble balances closer to the center of the channel and also reduces its deformation. Key Words: Bubble, Finite difference method / Front tracking, Poissell flow, Sloping channel, Capillary number.

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