تشكيل قطره در ميكرو كانال متقاطع، تحت تاثير ميدان الكتريكي با استفاده از روش شبكه بولتزمن

Droplet formation in microchannel under influence of electric field using the Boltzmann lattice method

تشكيل قطره، يكي از پديده‌هاي مهم در جريان‌هاي چندفازي است. همچنين، روش شبكه بولتزمن جزء روشهاي جديد و كاربردي مي‌باشد. در اين پژوهش شبيه‌سازي شكل‌گيري قطره بوسيله‌ي روش شبكه بولتزمن و تحت تاثير ميدان الكتريكي براي يك ميكروكانال متقاطع انجام شده‌است. براي اعمال ميدان الكتريكي، از مدل ليكي دي-الكتريك استفاده شده‌است. از مدل‌هاي مختلف تك‌فاز و دوفاز براي صحت‌سنجي آن بهره گرفته شده است. نتايج نشان مي‌دهد كه اعمال ميدان الكتريكي تاثير مثبتي در تسريع روند شكل‌گيري قطرات دارد، با اين كار قطرات كوچكتر با فركانس بالاتر بدست آمده است كه ايده ال و كنترل شده است.

The phenomena of formation and detachment of droplets are one of fundamental issues in
studying two-phase flows and have been seen in lots of natural phenomenon and processes,
such as spraying processes, ink jet printing, emulsion, etc. Between different numerical
methods, the lattice Boltzmann method (LBM) has been developed in to an alternative and
promising numerical scheme for simulating multi-component fluid flows. In this project,
formation and detachment of droplets were simulated, using LBM and particularly index
function model. Results were validated using two-phase flows methods. After code validation,
the formation and detachment of droplets in a cross-junction micro channel and under the
electric field effects were studied. To survey different effects on this phenomenon,
dimensionless numbers were studied.
Finally, the effect of variation of permittivity, conductivity and capillary number for droplets
were studied under different situations. Results show that the electric force have a positive
effect in expedition of droplet formation, and also index function model proved its very useful
abilities. We have smaller drops with high frequency which shows that we can control the
droplet formation.