The Electric Field Characteristics in Clevis Type Polymer Insulators Affected by Size and Contact Angle of the Contaminants: Simulation Approach

2021 ◽  
Author(s):  
I Made Yulistya Negara ◽  
I Gusti Ngurah Satriyadi Hernanda ◽  
Dimas Anton Asfani ◽  
Daniar Fahmi ◽  
Arief Budi Ksatria ◽  
...  
Keyword(s):  
Contact Angle ◽  
Electric Field ◽  
Simulation Approach ◽  
Polymer Insulators

Experimental Verification of Analytical Prediction of Pool Boiling CHF Incorporating the Effects of EHD and Contact Angle

2015 ◽  
Author(s):  
Ichiro Kano ◽  
Takahiro Sato ◽  
Naoki Okamoto
Keyword(s):  
Heat Transfer ◽  
Contact Angle ◽  
Electric Field ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Contact Angles ◽  
Dielectric Liquid ◽  
Working Fluid ◽  
Analytical Prediction ◽  
Compound Effect

Boiling heat transfer enhancement via compound effect of Electro-Hydro-Dynamic (EHD) and contact angle has been experimentally and analytically investigated. A fluorinated dielectric liquid (Asahi Glass Co. Ltd, AE-3000) was selected as the working fluid. Pool boiling heat transfer in the saturated liquid was measured at atmospheric pressure. In order to change the contact angle between the boiling surface and the dielectric liquid, the different materials Cu, Cr, NiB, Sn, and mixture of 5 and 1.5 micro meter diamond particles were electrically deposited on a boiling surface. The critical heat flux (CHF) for different contact angles showed 20.5 ∼ 26.9 W/cm2 which was −7 ∼ 25 % of that for a non-coated Cu surface (21.5 W/cm2). Upon application of a −5 kV/mm electric field to the micro structured surface (the mixture of 5 and 1.5 micro meter particles), a CHF of 99 W/cm2 at a superheat of 33.5 K was obtained. The previous theoretical equation of pool boiling predicted the CHF with the electric field and without the electrode.

A 3-D Numerical Modeling of Droplet Actuation via Electrowetting in Microchannels

2007 ◽  
Author(s):  
Alborz Arzpeyma ◽  
Ali Dolatabadi ◽  
Paula Wood-Adams
Keyword(s):  
Contact Angle ◽  
Numerical Modeling ◽  
Liquid Phase ◽  
Electric Field ◽  
Threshold Voltage ◽  
Contact Angle Hysteresis ◽  
Three Dimensions ◽  
Time Step ◽  
Droplet Behavior ◽  
Droplet Morphology

Numerical investigation is performed to study the droplet behavior under electrowetting actuation inside microchannels. Volume of Fluid (VOF) technique is employed to track the interface while the electric field is solved inside the whole domain in each time step simultaneously. The equations are solved in three dimensions for water as the liquid phase. Droplet morphology under the application of an electric field is investigated. Droplet velocity studied under different actuation voltages and compared to the experiments. Contact angle hysteresis and its effects on the threshold voltage are discussed.

Numerical simulation of EWOD on a printed circuit board for cleanroom-less digital fluidic manufacturing applications

2019 ◽  
Vol 38 (1) ◽  
pp. 119-137 ◽  
Author(s):  
Reza Hadjiaghaie Vafaie ◽  
Hossein Dehganpour ◽  
Abolfazl Moradpour
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Electric Field ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Angle Distribution ◽  
Content Type ◽  
Electrowetting On Dielectric ◽  
Printed Circuit ◽  
Wide Range

Purpose Digital microfluidic devices have been demonstrated to have great potential for a wide range of applications. These devices need expensive photolithography process and clean room facilities, while printed circuit board (PCB) technology provides high configurability and at low cost. This study aims to investigate the mechanism of electrowetting-on-a-dielectric (EWOD) on PCB by solving the multiphysics interaction between fluid droplet and electric field. The performance of system will be improved by inducing an efficient electric field inside the droplet. Design/methodology/approach To induce an electric field inside the droplet on a PCB and change the initial contact angle, the mechanism of EWOD is studied based on energy minimization method and a set of simulations are carried out by considering multiphysics interaction between the fluid droplet and external electric field. The performance of EWOD on a PCB system is investigated using different electrode structures. Findings Surface tension plays an efficient role in smaller sizes and can be used to move and control a fluid droplet on a surface by changing the interfacial surface tension. EWOD on a PCB system is studied. and it revealed that any change in electric field affects the droplet contact angle and as a result droplet deformation and movement. The electrode pattern is an important parameter which could change the electric potential distribution inside the droplet. Array of electrodes with square, zigzag interdigitated and crescent shapes are studied to enhance the EWOD force on a PCB substrate. Based on the results, the radial shape of the crescent electrodes keeps almost the same actuated contact line, applies uniform force on the droplet periphery and prevents the droplet from large deformation. A droplet velocity of 0.6 mm/s is achieved by exciting the crescent electrodes at 315 V. Furthermore, the behavior of system is characterized for process parameters such as actuation voltage, dielectric constant of insulator layer, fluidic material properties and the resultant velocity and contact angle. The study of contact angle distribution and droplet motion revealed that it is helpful to generate EWOD mechanism on a PCB which does not need more complicated fabrication processes. Originality/value The ability to handle and manipulate the droplets is very important for chemistry on-chip analysis such as immunoassay chips. Furthermore, a PCB-based electrowetting-on-dielectric device is of high interest because it does not need cleanroom facilities and avoids additional high-cost fabrication processes. In the present research, the EWOD mechanism is studied on a PCB by using different electrode patterns.

A Contact Line Dynamic Model for a Conducting Water Drop on an Electrowetting Device

2016 ◽  
Vol 20 (3) ◽  
pp. 811-834 ◽  
Author(s):  
Dongdong He ◽  
Huaxiong Huang
Keyword(s):  
Contact Angle ◽  
Electric Field ◽  
Contact Line ◽  
Water Drop ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Apparent Contact Angle ◽  
Two Phase ◽  
Maximum Deformation ◽  
Drop Motion

AbstractThe static shape of drop under electrowetting actuation is well studied and recent electrowetting theory and experiments confirm that the local contact angle (microscopic angle) is unaffected while the apparent contact angle (macroscopic angle) is characterized by the Lippmann-Young equation. On the other hand, the evolution of the drop motion under electrowetting actuation has received less attention. In this paper, we investigate the motion of a conducting water drop on an electrowetting device (EWD) using the level set method. We derive a contact line two-phase flow model under electrowetting actuation using energy dissipation by generalizing an existing contact line model without the electric field. Our model is consistent with the static electrowetting theory as the dynamic contact angle satisfies the static Young's equation under equilibrium conditions. Our steady state results show that the apparent contact angle predicted by our model satisfies the Lippmann-Young's relation. Our numerical results based on the drop maximum deformation agree with experimental observations and static electrowetting theory. Finally, we show that for drop motion our results are not as good due to the difficulty of computing singular electric field accurately. Nonetheless, they provide useful insights and ameaningful first step towards the understanding of the drop dynamics under electrowetting actuation.

scholarly journals Low frequency weak electric fields can induce structural changes in water

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260967
Author(s):  
Iman Rad ◽  
Rainer Stahlberg ◽  
Kurt Kung ◽  
Gerald H. Pollack
Keyword(s):  
Contact Angle ◽  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Low Frequency ◽  
Bulk Water ◽  
Platinum Electrodes ◽  
Exclusion Zone ◽  
Alternating Electric Fields ◽  
E 600

Low frequency electric fields were exposed to various water samples using platinum electrodes mounted near the water surface. Responses were monitored using a spectro-radiometer and a contact-angle goniometer. Treatment of DI (deionized), EZ (Exclusion Zone), and bulk water with certain electromagnetic frequencies resulted in a drop of radiance persisting for at least half an hour. Compared to DI water, however, samples of EZ and bulk water showed lesser radiance drop. Contact-angle goniometric results confirmed that when treated with alternating electric fields (E = 600 ± 150 V/m, f = 7.8 and 1000 Hz), droplets of EZ and bulk water acquired different charges. The applied electric field interacted with EZ water only when electrodes were installed above the chamber, but not beneath. Further, when DI water interacted with an electric field applied from above (E = 600 ± 150 V/m, f = 75 Hz), its radiance profile became similar to that of EZ water. Putting these last two findings together, one can say that application of an electric field on DI water from above (E = 600 ± 150 V/m, f = 7.8 to 75 Hz) may induce a molecular ordering in DI water similar to that of EZ water.

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