کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
154917 456874 2014 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Capillary torque on a rolling particle in the presence of a liquid film at small capillary numbers
ترجمه فارسی عنوان
گشتاور موازی در یک ذره نورد در حضور یک فیلم مایع در تعداد مویرگی کوچک
کلمات کلیدی
پل مایع، نیروی موازی، رولینگ، جریان گرمای مرطوب گشتاور موازی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی


• Two mechanisms analyzed for capillary torque on rolling particle with liquid film.
• One part of torque associated with rearward shift of liquid bridge.
• Second part associated with asymmetry of advancing and receding contact angles.
• Capillary torque is found to vary as a power-law with capillary number.
• Good agreement with experimental data for particle rolling down inclined slope.

A theoretical analysis was developed for the capillary torque acting on a spherical particle rolling on a flat surface in the presence of a thin liquid film. The capillary number (the ratio of viscous force to surface tension force) is assumed to be sufficiently small that the liquid bridge has a circular cross-section. The theory identifies two mechanisms for capillary torque. The first mechanism results from the rearward shift of the liquid bridge in the presence of particle rolling, which causes the line of action of the pressure force within the liquid bridge to be located behind the particle centroid, inducing a torque that resists particle rolling. The second mechanism results from the contact angle asymmetry on the advancing and receding sides of the rolling particle, which leads to a net torque on the particle arising from the tangential component of the surface tension force. Estimates for these two types of capillary torque are obtained using experimental data, and correlations for both torques are obtained in the form of power-law fits as functions of the capillary number. When combined with a standard expression for viscous torque on a rolling particle, the capillary torque expressions are found to yield predictions for particle terminal velocity that are in good agreement with experimental data for a particle rolling down an inclined surface.

Figure optionsDownload high-quality image (103 K)Download as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Engineering Science - Volume 108, 28 April 2014, Pages 87–93
نویسندگان
,