Electrohydrodynamic enhancement

Laohalertdecha, S., Naphon, R and Wongwises, S. (2007). A review of electrohydrodynamic enhancement of heat transfer. Renewable and Sustainable Energy Reviews, Vol. 11, pp. 858-876. 

An alternative new technology, an electrohydrodynamic (EHD)-enhanced polarization pump, is being developed to deliver and maintain an ultra thin film of the fluid on a surface (Figure 7), which will enable high efficiency spot cooling of high heat flux electronics [6]. An array of EHD electrodes acts to draw an ultra thin film of fluid over the hot surface. The working fluid evaporates and removes... 

In order to stimulate condensate motion under zero-G conditions, other forces must replace the gravitational force. This may be done by centrifugal forces, vapor shear forces, surface tension forces, suction forces, and forces created by an electric field. McEver and Hwangbo [133] and Valenzuela et al. [134] describe how surface tension forces may be used to drain a condenser surface in space. Tanasawa [1] reviews electrohydrodynamics (EHD) enhancement of condensation. Bologa et al. [135] showed experimentally that an electric field deforms the liquid-vapor interface, creating local capillary forces that enhance the heat transfer. 

Electrical fields. Here, electrohydrodynamic (EHD) methods are used to enhance CHF. Increases of up to around a factor of 5 are possible by this technique. An example of this work is that of Markels and Durfee [177], who obtained an increase in CHF by a factor of 4.5 by the application of 7,000 volts DC to a 9.5-mm tube in pool boiling of isopropanol at atmospheric pressure. 

Electrostatic fields, the application of which is sometimes known as electrohydrodynamics (EHD), are of growing interest in the inventory of tools for heat and mass transfer enhancement. Normally limited in their application to dielectric fluids, such as refrigerants and transformer oil, the high voltages (and low currents) associated with such fields are reflected in increased activity close to the heat transfer surface. The technique has been successfully used to enhance boiling and condensation - see Allen et al. (1995) for an historical review. 

Electrohydrodynamics - an enhancement method for boiling/condensation and single phase (corona wind) effects (see also magnetohydrodynamics below). 

The term active mixer or active microimxef refers to a microfluidic device in which species mixing is enhanced by the application of some form of external energy disturbance. Typically, this disturbance is generated either by moving components within the micromixer itself, e.g. magnetically-actuated stirrers, or by the application of an external force field, e. g. pressure, ultrasound, acoustic, electrohydrodynamic, electrokinetic, dielectrophoretic, magneto-hydrodynamic, thermal, and so forth [1]. 

The ion mobility may also be enhanced by electrohydrodynamic motions. If the change in fluid kinetic energy equals the electrostatic field energy... 

The field-enhancement ionic mobility can result from two different mechanisms. One is electrohydrodynamical (EHD) convection, which appears in its strong, turbulent form at 10 kV. According to this mechanism, ions are carried about by liquid flow, which is considerably faster than their own drift. The transport enhancement, T, is ... 

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