کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
671505 1459097 2008 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Pressure-oscillation defoaming for viscoelastic fluid
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Pressure-oscillation defoaming for viscoelastic fluid
چکیده انگلیسی

The enhancement of bubble rising velocity was experimentally investigated by mechanically applying an oscillating pressure to a single small air bubble (e.g., 1 mm3) in a viscoelastic fluid. For shear-thinning fluids, the cyclic change in bubble diameter induced by the oscillating pressure generates a continuous strong local flow near the bubble surface. Consequently, the apparent liquid viscosity is reduced and the bubble rising velocity increases by 400 times or more compared to the case without oscillating pressure. However, for a Newtonian fluid, almost no effect was observed with oscillating pressure. Time-series data of the longitudinal and horizontal bubble diameters were obtained experimentally using a stroboscope and a video system, and these data were used to estimate the local shear rate and the local shear viscosity. The increase in bubble rising velocity estimated from the shear viscosity behavior agreed well with the experimental data. Additionally, a periodic change in the bubble shape from a sphere at the maximum bubble size to a cusped shape at the minimum bubble size was observed under strong oscillatory pressure.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Newtonian Fluid Mechanics - Volume 151, Issues 1–3, 16 May 2008, Pages 30–37
نویسندگان
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