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1

An analysis on the velocity of dust particles in the plate-type electrostatic precipitators used in thermoelectric power plants

Popa G. N., Şora I., Dinis C. M., Deaconu S. I.

Environment Protection Engineering

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2014

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Vol. 40, nr 1

85--102

EN

Experimental data collected from different plate-type electrostatic precipitators used in a thermoelectric power plant has been analyzed. The following parameters were considered: the collection efficiency, average migration velocity of dust particles, velocity distribution of the gas in the input and output channels of precipitators. The average migration velocity of dust particles can be estimated using various mathematical models, and the gas velocity can be computed using the velocity distributions from the input channels of the precipitators. The traveling time of dust particles between the electrodes is smaller than the traveling time along the precipitator sections.

2

Effect of dust particles on a Soret- driven ferrothermohaline convection in a rotating medium

Hemalatha R., Sekar R., Vaidyanathan G.

International Journal of Applied Mechanics and Engineering

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2012

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Vol. 17, no. 2

367-381

EN

In ferrofluids three components namely, the core, surfactant and carrier fluids coexist. Thermal convection in a multicomponent fluid has wide applications in industrial, ionospheric and geothermal systems. In this paper the effect of dust particles on a Soret-driven ferrothermohaline convection in a rotating system heated and soluted from below subjected to a transverse uniform magnetic field is examined using linear stability analysis. An exact solution is obtained for the case of two free boundaries. Both stationary and oscillatory instabilities are investigated. The oscillatory modes are introduced due to the presence of dust particles, the stable solute gradient and rotation and the oscillatory modes are not allowed in their absence. In the case of stationary convection, the non-buoyancy magnetization parameter, the dust particle parameter destabilize the system. The Soret-coefficient, rotation and the stable solute gradient stabilize the system. The results are presented graphically.

3

Effect of rotation on a Soret-driven thermohaline convection in dusty ferrofluids saturating a porous medium

Hemalatha R., Sekar R., Vaidyanathan G.

International Journal of Applied Mechanics and Engineering

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2011

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Vol. 16, no 4

1021-1036

EN

Soret driven thermoconvective instability in multicomponent fluids has wide applications in heat and mass transfer. This paper deals with the theoretical investigation of the effect of rotation on a Soret-driven ferrothermohaline convection heated and soluted from below subjected to a transverse uniform magnetic field in the presence of dust particles saturating a porous medium. Brinkmann model is used. An exact solution is obtained for the case of two free boundaries. Both stationary and oscillatory instabilities are investigated using the linear stability analysis and normal mode technique. The oscillatory modes are introduced due to the presence of dust particles, the stable solute gradient and rotation and the oscillatory modes are not allowed in their absence. For the case of stationary convection, the non-buoyancy magnetization parameter, the dust particle parameter and large values of permeability of the porous medium destabilize the system. The soret coefficient, rotation and the stable solute gradient stabilize the system. The results are presented graphically.

4

Visualization of dust particles motion in back discharge

Krupa A., Lackowski M., Czech T.

Environment Protection Engineering

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2006

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Vol. 32, nr 4

53-58

EN

The back discharge takes place in an industrial electrostatic precipitation process, especially in coal-fired power plants whose operation is based on low-sulfur coal. This type of discharge occurs simultaneously with corona discharge on an electrode covered with a high-resistivity dust layer. The charge that accumulates on the dielectric layer surface is responsible for an increase in the magnitude of electric field within the dielectric layer and a decrease in the magnitude of electric field between the electrodes. The breakdown of dielectric layer increases the discharge current and the re-entraining of dust particles from collecting electrode into the flowing gas. The motion of dust particles emitted from the collecting electrode and an air flow pattern were investigated. Additionally, acrylic powder layer placed between a mica plate with a small pinhole and the plate electrode was also used in the experiments in order to generate a repeatable back discharge.

PL

Wyładowanie wsteczne występuje podczas użytkowania elektrofiltrów w przemyśle wykorzystującym niskozasiarczony węgiel. Wyładowanie wsteczne pojawia się wówczas, gdy elektrodę osadczą pokrywa warstwa pyłu o dużej rezystywności. Gromadzący się na powierzchni warstwy ładunek powoduje wzrost natężenia lokalnego pola elektrycznego w obszarze warstwy dielektrycznej oraz spadek natężenia pola elektrycznego w przestrzeni międzyelektrodowej. Wskutek przebicia warstwy dielektrycznej wzrasta natężenie prądu wyładowania oraz emisja pyłu zebranego na elektrodzie zbiorczej do przepływającego powietrza. Przedstawiono ruch cząstek pyłu emitowanych z elektrody zbiorczej oraz strukturę przepływu powietrza wokół elektrody wyładowczej. W badaniach wykorzystano również układ modelowy, w którym warstwą dielektryczną była płytka miki, a zamiast pyłu z elektrofiltru wykorzystano pył akrylowy.