Relaxation of characteristics of electrohydrodynamic converters
Închide
Articolul precedent
Articolul urmator
444 0
SM ISO690:2012
KOZHEVNIKOV, Igor, BOLOGA, M.. Relaxation of characteristics of electrohydrodynamic converters. In: Materials Science and Condensed Matter Physics, Ed. 8-th Edition, 12-16 septembrie 2016, Chişinău. Chişinău: Institutul de Fizică Aplicată, 2016, Editia 8, p. 337. ISBN 978-9975-9787-1-2.
EXPORT metadate:
Google Scholar
Crossref
CERIF

DataCite
Dublin Core
Materials Science and Condensed Matter Physics
Editia 8, 2016
Conferința "International Conference on Materials Science and Condensed Matter Physics"
8-th Edition, Chişinău, Moldova, 12-16 septembrie 2016

Relaxation of characteristics of electrohydrodynamic converters


Pag. 337-337

Kozhevnikov Igor, Bologa M.
 
Institute of Applied Physics, Academy of Sciences of Moldova
 
Disponibil în IBN: 6 august 2019


Rezumat

Application of high strength electric fields for turbulisation and transport of one and two phase heat carriers is one of the most effective methods of intensification of heat and mass transfer.   The arrangement of circulation of heat carriers in heat exchangers from the heat supply zone to the cooler is a complicated problem, since the specified geometry, surface conditions of the electrodes and the channel, electrophysical properties of the heat carrier are necessary. With this aim various constructions of electrohydrodynamic (EHD) converters are developed that consist of two dramatically asymmetric electrodes working as a pump. At the emitter electrode ions are generated in the dielectric liquid due to the great field inhomogenuity. They move to the collector electrode under the action of coulomb forces and entrain neutral molecules. A part of the ions neutralize at the collector; the nonrecombined ions move out the interelectrode gap. This initiates a circulation of the heat carrier along the heat exchanger channels. The pressure and consumption characteristics of EHD converters were obtained as a function of the electrode geometry and electrophysical properties of the dielectric liquid. However, the problems of stability of the output characteristics that are of primary importance for practical application were not studied in the published literature.     In this communication the results are presented of the endurance tests of one-stage EHD converterы of the type “lattice with a perforated isolation coating–lattice” made of copper wires. The installation consists of a closed organic glass vessel divided by a dielectric buffle into two parts filled with kerosene (s= 3×10-10 Ohm-1×m-1). There are two holes in the buffle; one of the holes involves a stage of the EHD converter that provides circulation of the heat carrier from one cell to another and back through the second hole. At the same time the collector leakage current, dynamic and static pressure produced by the converter, and kerosene electric conduction were registered. The tests were performed during 4 years of continuous operation of the converter. The static and dynamic pressure characteristics reduced by 30% and 50%, respectively; the leakage current also respectively reduced. The lowering of the kerosene conduction during the first days was registered due to the electric purification of the working medium. After the converter operated during four years deposits formed at the electrodes, especially at the collector (see the figure); this lead to deterioration of the pressure and consumption characteristics. An incomplete neutralization of the medium near the collector that moves along the contour and reaches the emitter also exerts the influence. One should take into account a negative impact of electrode corrosion in kerosene stated experimentally, probable polymerization processes of dielectric liquid under the action of high strength fields found out in the transformer oil, and microdischarges at the electrode–liquid boundary; their products precipitate on the collector surface. Therefore, relaxation of the characteristics of EHD convertors is primarily associated with formation of deposits on the electrodes, especially at the collector electrode.