Visualization of Vertical Bubble Coalescence and Detachment Under the Influence of a Nonuniform Electric Field

2006 ◽  
Author(s):  
Z. Liu ◽  
C. Herman ◽  
D. Mewes
Keyword(s):  
Electric Field ◽  
Nonuniform Electric Field ◽  
Bubble Coalescence ◽  
Behavior Patterns ◽  
Air Bubbles ◽  
Bubble Behavior ◽  
Single Experiment ◽  
Flow Rates ◽  
Lower Volume ◽  
Detachment Time

The effect of a nonuniform electric field on the formation, coalescence and detachment of air bubbles injected into a stagnant, isothermal liquid through an orifice is studied to identify characteristic bubble behavior patterns. The results of the experimental visualization suggest significant differences in bubble shape and size caused by the electric field. The electric field was applied between a flat, circular and horizontal ground electrode and a spherical, off-axis top electrode. During formation the bubble was tilted towards or away from the upper electrode under the influence of the electric field. The direction of the tilt alternated (even in a single experiment), however, in the majority of the cases the bubble trajectory tilted towards the top electrode. The detachment frequency increased under the influence of the electric field, which indicates decreased bubble volume for lower volume flow rates. The effect of the electric field on vertical bubble coalescence was analyzed and quantified in terms of the detachment time.

Heat Transfer and Bubble Detachment in Subcooled Pool Boiling From a Microheater Array Under the Effect of a Nonuniform Electric Field

2007 ◽  
Author(s):  
Zan Liu ◽  
Cila Herman ◽  
Jungho Kim
Keyword(s):  
Heat Transfer ◽  
Electric Field ◽  
Pool Boiling ◽  
Nonuniform Electric Field ◽  
Working Fluid ◽  
Dielectric Fluid ◽  
Bubble Behavior ◽  
Bubble Detachment ◽  
Earth Gravity ◽  
The Individual

The effects of a nonuniform electric field on vapor bubble detachment and heat transfer rate were studied in pool boiling at different subcooled conditions for various wall temperatures. Dielectric fluid (FC-72) was used as the working fluid at 1 atm at earth gravity with two extreme gas concentration levels. An array of 3×3 independently controlled microheaters each 0.7×0.7 mm2 in size were maintained at constant temperature using electronic feedback loops, enabling the heat transfer from each heater to be determined. An electric field was applied between the horizontal upward facing microheater array, which was grounded, and a spherical, off-axis top electrode. Boiling heat transfer results with and without the electric field are presented in this study. Without the electric field, a single large “primary” bubble was observed to form due to the coalescence of the individual “satellite” bubbles which nucleated directly from each single heater array. Before its detachment, a dry spot formed underneath this primary bubble resulted in a reduction in heat transfer. With the electric field applied, three or more small “secondary” bubbles that nucleated and grew more rapidly and detached more frequently were observed. Due to the nonuniformity of the electric field, bubbles moved away from the top electrode (into the weaker region of the electric field) during their development. Higher overall heat transfer rates were measured from the heater array. In addition, the bubble behavior showed agreement with our previous investigation of injecting air bubbles into a stagnant, isothermal liquid through orifices.

Breakdown of gas gaps in a nonuniform electric field at a subnanosecond voltage pulse rise time

2013 ◽  
Vol 58 (3) ◽  
pp. 370-374 ◽  
Author(s):  
A. M. Boichenko ◽  
V. F. Tarasenko ◽  
E. Kh. Baksht ◽  
A. G. Burachenko ◽  
M. V. Erofeev ◽  
...  
Keyword(s):  
Electric Field ◽  
Rise Time ◽  
Voltage Pulse ◽  
Nonuniform Electric Field ◽  
Pulse Rise Time

Electrostatic Dispensing of Dry Dielectric Materials

2001 ◽  
Vol 700 ◽  
Author(s):  
Malinda M. Tupper ◽  
Marjorie E. Chopinaud ◽  
Takamichi Ogawa ◽  
Michael J. Cima
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Dielectric Materials ◽  
Nonuniform Electric Field ◽  
Sodium Fluorescein ◽  
Silica Spheres ◽  
Electrode Geometry ◽  
Wide Range ◽  
Silica Beads

AbstractDispensing micron-scale dielectric materials can be achieved through the use of dielectrophoresis. Electrodes are designed to create a nonuniform electric field. This method is expected to be applicable for transfer of a wide range of dielectric powders as well as small, shaped components. Small, 150 μm diameter silica spheres, as well as sodium fluorescein powder have been dispensed by this method. Selecting the appropriate electrode geometry and electric field intensity controls the amount collected. As little as 1.0 μg of sodium fluorescein powder, and as much as 16 mg of silica beads have been collected, and repeatability within 10 % of the total amount dispensed has been achieved.

scholarly journals Formation of single charged drops from a dielectric liquid jet in a nonuniform electric field.

1990 ◽  
Vol 16 (4) ◽  
pp. 700-705 ◽  
Author(s):  
Takashi Hibiki ◽  
Manabu Yamaguchi ◽  
Takashi Katayama
Keyword(s):  
Electric Field ◽  
Nonuniform Electric Field ◽  
Dielectric Liquid ◽  
Liquid Jet

scholarly journals Colloidal particle electrorotation in a nonuniform electric field

2018 ◽  
Vol 97 (1) ◽  
Author(s):  
Yi Hu ◽  
Petia M. Vlahovska ◽  
Michael J. Miksis
Keyword(s):  
Electric Field ◽  
Colloidal Particle ◽  
Nonuniform Electric Field

scholarly journals Numerical Study of Formation of a Series of Bubbles from an Orifice by Applying Dynamic Contact Angle Model

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Nan Chen ◽  
Xiyu Chen ◽  
Antonio Delgado
Keyword(s):  
Contact Angle ◽  
Gas Flow ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Static Contact Angle ◽  
Bubble Shape ◽  
Flow Rates ◽  
Bubble Detachment ◽  
Static Contact ◽  
Detachment Time

The dynamic contact angle model is applied in the formation process of a series of bubbles from Period-I regime to Period-II regime by using the VOF method on a 2D axisymmetric domain. In the first process of the current research, the dynamic contact angle model is validated by comparing the numerical results to the experimental data. Good agreement in terms of bubble shape and bubble detachment time is observed from a lower flow rate Q = 150.8 cm3/min (Re = 54.77, Period-I regime) to a higher flow rate Q = 603.2 cm3/min (Re = 219.07, Period-III regime). The comparison between the dynamic contact angle model and the static contact angle model is also performed. It is observed that the static contact angle model can obtain similar results as the dynamic contact angle model only for smaller gas flow rates (Q ≤ 150.8 cm3/min and Re ≤ 54.77)). For higher gas flow rates, the static contact angle model cannot produce good results as the dynamic contact angle model and has larger relative errors in terms of bubble detachment time and bubble shape.

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