Development of a bi-directional electrohydrodynamic pump: Parametric study with numerical simulation and flow visualization

Abstract

We propose a bi-directional electrohydrodynamic pump developed for transporting dielectric liquid, where the electrodes are symmetrically configured but the applied voltage is non-symmetric. The underlying principle for liquid transport comes from the so-called Onsager effect, which states that the ion concentration is increased as the electric field is increased. Multi-physics software is used to perform numerical simulation for the fluid flow, the electric potential, and the transport of ion concentrations for two kinds of electrode patterns. A flow-visualization experiment is also conducted to verify the physical models and numerical methods employed. It is found that significant reduction of the ion recombination constant is required to get matching of the experimental and simulation results. We demonstrate through a parametric study that there is an optimum distance between two large grounded electrodes for producing a maximum pumping velocity at the diameter of two small electrodes fixed at 0.3 mm. The effect of the size of large grounded electrodes on the pumping performance is also studied in terms of streamlines, electric field, and charge distribution. A general account is also given of the basic ideas of electrode arrangement for the enhancement of pumping.

Self-contained soft electrofluidic actuators

“…In such nonuniform and strong electric field, Wien effect occurs. The Wien effect ( 31 – 37 ) is a phenomenon in which the equilibrium between ion pairs and free ions is destroyed and the dissociation rate becomes greater than the recombination rate when the dielectric liquid is under the strong nonuniform electric field. This is because uncontrolled chemical impurities exist naturally in even a pure dielectric liquid.…”

“…However, local variation of the field intensity leads to a nonzero gradient of the ion concentrations, which then causes a relatively small amount of concentration difference between the cation and anion, corresponding to nonuniform field–induced space charge density. The space charge density can be given by the formula q = − K Ε ⋅ ∇ E ( 31 – 33 , 35 , 37 – 38 ), where K = 2ε 0 ε r γ > 0 is a constant (ε 0 and ε r are the vacuum permittivity and the relative permittivity of the liquid, respectively, and γ is the Onsager constant). Thus, it is obvious from this equation q = − K Ε ⋅ ∇ E that space charge density is determined by electric field Ε and its gradient ∇ E .…”

Influence of Electrohydrodynamic Flows on the Intensification of the Heat and Mass Exchange Processes. Part I. Electrohydrodynamic Flows and Characteristics of Single-Stage Electrohydrodynamic Pumps

“…От степени электризации среды на эмиттере зависят расходные и напорные характеристики насоса. Поэтому практически в большинстве конструкций ЭГДН используются геометрически асимметричные электроды [7][8][9][10].…”

“…Oн применяется при исследовании процессов тепло-и массопереноса [17,18], смешения газов или жидкостей, явления распространения пламени или изучении сверхзвуковых потоков, где градиенты плотности достаточны для большого отклонения света. Шлирен-метод не вносит какие-либо неоднородности в среду, в отличие от микрочастиц, используемых для визуализации ЭГД-течений [6,9], позволяет выявить характер течения, дает представление о диссипативных (возвратных) течениях и турбулизации потока, оказывающих влияние на эффективность работы насоса.…”

Analysis of the Movement Characteristics of Corona Winds during Needle-Plate Discharge

“…Dong Sik Cho [22] conducted numerical analysis on the influence of charged ions in the dielectric fluid on liquid flow, and proposed a mechanism for the movement of a bidirectional electric water pump. Quentin Lancereau [23] revealed the connection between the electric field and the flow field by putting forward a model of the electrofluid dynamic field generated in an on-line/cylindrical axisymmetric electrostatic precipitator under laminar flow.…”