Numerical Study of Dielectric Fluid Bubble Behavior within Diverging External Electric Fields

Past research in the area of pool boiling within the presence of electric fields has generally focused on the case of uniform field intensity. Any numerical or analytical studies of the effect of non-uniform fields on the motion of bubbles within a dielectric liquid medium have assumed that the bubbles will retain their spherical shape rather than deform. These studies also ignore changes to the electrical field caused by the presence of the bubbles. However, these assumptions are not necessarily accurate as, even in the case of a nominally uniform electric field distribution, bubbles can exhibit considerable physical deformation and the field can become noticeably affected in the vicinity of the bubble. This study explores the effect that a non-uniform electric field can have on vapor bubbles of a dielectric fluid by modeling the physical deformation of the bubble and the alteration of the surrounding field. Numerical results show that the imbalance of electrical stresses at the bubble surface exerts a net dielectrophoretic force on the bubble, propelling the bubble to the vicinity of weakest electric field, thereby enhancing the separation of liquid and vapor phases during pool boiling. However, the proximity of the bubble to one of the electrodes can considerably alter the bubble trajectory due to an attractive force that arises from local distortions of the potential and electric fields. This phenomenon cannot be predicted if bubble deformation and field distortion effects are neglected.

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Numerical Study of Dielectric Fluid Bubble Behavior Within Diverging External Electric Fields

Journal of Heat Transfer ◽

10.1115/1.2804937 ◽

2008 ◽

Vol 130 (3) ◽

Cited By ~ 3

Author(s):

Matthew R. Pearson ◽

Jamal Seyed-Yagoobi

Keyword(s):

Mathematical Model ◽

Electric Field ◽

Electric Fields ◽

Numerical Study ◽

Electrode Spacing ◽

Small Scale ◽

Arbitrary Distribution ◽

Dielectric Fluid ◽

Reciprocal Effect ◽

Bubble Deformation

A three-dimensional mathematical model is presented that models bubble deformation of a dielectric fluid due to the presence of a nonuniform electric field and calculates the net dielectrophoretic force that is exerted by the electric field on the bubble. The study includes the development of a method of predicting the shape of a bubble based on the arbitrary distribution of stresses over its surface without requiring an axisymmetric configuration. The reciprocal effect of the bubble’s presence on the electric field is also incorporated into the model, and dimensional analysis is used to obtain a single key parameter that governs the bubble deformation phenomenon. Numerical implementation of the mathematical model shows that the bubble deformation can be significant. Furthermore, bubble deformation and electric field distortion can have significant effects on the dielectrophoretic behavior of bubbles in nonuniform fields, especially within small-scale devices where the bubble size and electrode spacing are similar in magnitude.

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Emulsions in external electric fields

Advances in Colloid and Interface Science ◽

10.1016/j.cis.2021.102455 ◽

2021 ◽

pp. 102455

Author(s):

Johan Sjöblom ◽

Sameer Mhatre ◽

Sébastien Simon ◽

Roar Skartlien ◽

Geir Sørland

Keyword(s):

Electric Fields ◽

External Electric Fields

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Hydrogen and Halogen Bonding in Homogeneous External Electric Fields: Modulating the Bond Strengths

Chemistry - A European Journal ◽

10.1002/chem.202102284 ◽

2021 ◽

Author(s):

Li Chen ◽

Jingshuang Dang ◽

Juan Du ◽

Changwei Wang ◽

Yirong Mo

Keyword(s):

Electric Fields ◽

Halogen Bonding ◽

External Electric Fields ◽

Bond Strengths

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Vacancy tuned thermoelectric properties and high spin filtering performance in graphene/silicene heterostructures

Scientific Reports ◽

10.1038/s41598-021-94842-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zainab Gholami ◽

Farhad Khoeini

Keyword(s):

Electric Fields ◽

High Spin ◽

High Efficiency ◽

Practical Applications ◽

External Electric Fields ◽

Ferromagnetic Exchange ◽

High Spin Polarization ◽

Filtering Effect ◽

Spin Switching ◽

Spin Filtering

AbstractThe main contribution of this paper is to study the spin caloritronic effects in defected graphene/silicene nanoribbon (GSNR) junctions. Each step-like GSNR is subjected to the ferromagnetic exchange and local external electric fields, and their responses are determined using the nonequilibrium Green’s function (NEGF) approach. To further study the thermoelectric (TE) properties of the GSNRs, three defect arrangements of divacancies (DVs) are also considered for a larger system, and their responses are re-evaluated. The results demonstrate that the defected GSNRs with the DVs can provide an almost perfect thermal spin filtering effect (SFE), and spin switching. A negative differential thermoelectric resistance (NDTR) effect and high spin polarization efficiency (SPE) larger than 99.99% are obtained. The system with the DV defects can show a large spin-dependent Seebeck coefficient, equal to Ss ⁓ 1.2 mV/K, which is relatively large and acceptable. Appropriate thermal and electronic properties of the GSNRs can also be obtained by tuning up the DV orientation in the device region. Accordingly, the step-like GSNRs can be employed to produce high efficiency spin caloritronic devices with various features in practical applications.

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