بررسی اثر تغییر شکل سطح مقطع یک مانع بیضوی بر رسوب میکرو ذرات داخل کانال به روش شبکه بولتزمن

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی مکانیک، دانشگاه کاشان، کاشان، ایران

چکیده

در کار حاضر رسوب میکروذرات برای جریان در کانال با مانع بیضوی با مساحت ثابت اما با ضریب شکل‌های متفاوت بررسی شده است. شبیه‌سازی عددی به‌روش شبکه بولتزمن به‌همراه روش لاگرانژی برای مسیریابی ذرات انجام شده است. مدل شبکه­ی استفاده شده در کار حاضر مدل دو بعدی و 9 سرعته،9Q2D، است. از شرط مرزی منحنی شکل برای مرز موانع استفاده شده است. ذرات با شرایط استاندارد در ورودی کانال تزریق شده‌اند. گرانش، نیروی دراگ، نیروی براونی و نیروی لیفت سافمن در معادله حرکت ذرات در نظر گرفته شده است. پارامتر هندسی نسبت اقطار مانع که به‌عنوان ضریب شکل در نظر گرفته می‌شود با پارامترهای جریان مانند عدد رینولدز برای رسوب و پراکندگی ذرات در نظر گرفته شده‌اند. نتایج مورد نظر برای هر دو متغیر ضریب شکل و عدد رینولدز با 8 ضریب شکل و 5 عدد رینولدز مختلف بررسی شده­اند. نتایج نشان از تأثیر ضریب شکل بر روی جریان سیال با ممانعت از عبور جریان و تغییر در نوع جریان دارد. این تغییر در اعداد رینولدز مختلف نیز قابل مشاهده است. همچنین تغییر ضریب شکل با تغییر در نوع جریان و مکانیزم‌ها‌ی رسوب باعث تغییر در نیروهای وارده بر ذرات و رسوب ذرات می‌شود. به‌طور کلی تأثیر متغیرهای مورد نظر با تعداد ذرات رسوب شده تفسیر شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigating the Effect of Changing the Shape of the Cross Section of an Elliptical Obstacle on the Deposition of Micro Particles Inside the Channel Using the Boltzmann Network Method

نویسندگان [English]

  • Babak Roshani
  • Ahmadreza Rahmati
Department of Mechanical Engineering, University of Kashan, Kashan, Iran
چکیده [English]

In the current study, transportation of the microparticles deposition through a channel has been investigated where elliptical obstacle with constant cross sectional area but different shape factors was assumed in the channel. Numerical simulation was conducted using lattice Boltzmann method, and Lagrange method was used for particle tracking. A two-dimensional and nine-velocity model was used as the network model. A curved boundary condition was applied for the obstacle 
boundaries. In the designed model, particles at standard condition were injected at the inlet of the channel. Gravity force, drag force, Brownian force and Soffman lift force were applied in the motion equation of the particles. The effect of shape factor as a geometrical parameter, which was defined as the ratio of the diameters of elliptical obstacle, and the flow parameters such as Reynolds’ number was examined on the particle deposition and particle scattering. Results were examined at eight different shape factors and five different Reynolds numbers .Results revealed that the change in the shape factor varies the effect of the obstacle in the flowing stream, and also changes the flow regime. This variation was obtained at different Reynolds numbers. Furthermore, changes of the shape factor associated with variations in the flow regime and deposition mechanisms, changes the forces exerted on the particles. Generally, the effect of the mentioned parameters can be interpreted based on the number of the precipitated particles.
 

کلیدواژه‌ها [English]

  • lattice Boltzmann method
  • Particle Tracking
  • Deposition Mechanism
  • Shape Factor
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