Nine-point simplified variable-mesh finite-difference formulations of Poisson's equation

Vijayan, T.

doi:10.1016/s0168-9002(98)01430-2

Cited by 5 publications

(3 citation statements)

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“…In (11), η is made up of the various dissipation terms resulting from the different energy coupling mechanisms. 10, 17-21 These terms are: the classical Coulomb (η c ) and the electron-neutral (η e-n ) both of which resulted from the direct-energy transfer by the particle collisions, the η e-e term of the electron-electron two stream-wave origin, and η ia of the ion-acoustic wave origin created by the instabilities of hydrodynamic turbulence, so that η is…”

Section: B Diode Current and Heatingmentioning

confidence: 99%

A model of the generation and transport of ozone in high-tension nozzle driven corona inside a novel diode

Vijayan¹,

Patil²

2012

Review of Scientific Instruments

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The genesis and transport of ozone (O(3)) are investigated in a novel plasma diode and described in this paper. The innovative cathode (K) of this axial symmetric diode which operated at the high voltage (φ(0)), has a large number of sharpened nozzles located on different radial planes of its central tubular-mast and is encircled by the anode (A). The nozzles played the dual role of oxygen (O(2)) injection as well as creation of high electric field (E) in the A-K gap, enabled the formation of a cold corona. Electrons in the corona under the influence of E moved towards anode, collided with O(2) and created the O radicals. O in turn joined the free O(2) and formed O(3). The evolution of O(3) here is modeled in various O(2) pressure (P), electron density (n(e)), and temperature (T) in terms of the major reaction modes involving e, O, O(2), and O(3). Typical steady state O(3) density attained so in P ~ bar, n(e) ~ 10(15) m(-3) and T ~ 300 K is over 10(25) m(-3) and that of O lower ~10(20) m(-3). Both the O and O(3) densities increased with an enhanced n(e) of avalanche multiplications in corona. O(3) increased also with a higher P but the temporal O reversed in trend midway and reduced with P towards the steady state. A sharp decline in diode resistance with smaller A-K gap induced finite discharge current and led to the undesired heating of corona. It is shown that the O(3) density reduced with the temperature rise but O density reduced with the T rise up to 500 K and then rose modestly with the further T increase.

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Section: B Diode Current and Heatingmentioning

confidence: 99%

A model of the generation and transport of ozone in high-tension nozzle driven corona inside a novel diode

Vijayan¹,

Patil²

2012

Review of Scientific Instruments

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“…For the present axially symmetric diode geometry, the Poisson's equation (8) is written in a 5-point matrix r-z finite difference [8,11] form as:…”

Section: Computation Proceduresmentioning

confidence: 99%

Modeling and characterization of field-enhanced corona discharge in ozone-generator diode

Patil¹,

Vijayan²

2010

J. Phys.: Conf. Ser.

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Abstract. Electric field enhanced corona plasma discharge in ozone generator diode of axial symmetry has been investigated and characterized in theory. The cathode K of diode is made of a large number of sharpened nozzles arranged on various radial planes on the axial mast and pervaded in oxygen gas inside the anode cup A, produces high fields over MV/m and aids in the formation of a corona plume of dense ozone cloud over the cathode surface. An r-z finite difference scheme has been devised and employed to numerically determine the potential and electric field distributions inside the diode. The analyses of cathode emissions revealed a field emission domain conformed to modified ChildLangmuir diode-current. Passage of higher currents (over µA) in shorter A-K gaps d gave rise to cathode heated plasma extending from the corona to Saha regimes depending on local temperature. Plasma densities of order 10 2 -10 6 m -3 are predicted in these. For larger d however, currents are smaller and heating negligible and a negative corona favoring ozone formation is attained. High ozone yields about 20 per cent of oxygen input is predicted in this domain. The generator so developed will be applied to various important applications such as, purification of ambient air /drinking water, ozone therapy, and so on.

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“…ε is relative permittivity of oxygen gas, and 0 ε is permittivity of free space. Equation (6) is described in a five-point finite-difference form [6] and solved employing MATLAB [7] and successive over-relaxation. Potential and field distributions were determined inside the plasma diode in various schemes and the details of studies and results reported elsewhere [4].…”

Section: Corona Plasma Diodementioning

confidence: 99%

High-tension corona controlled ozone generator for environment protection

Vijayan¹,

Patil²

2010

J. Phys.: Conf. Ser.

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Abstract. Engineering details of a high voltage driven corona-plasma ozone generator are described. The plasma diode of generator has coaxial cylindrical geometry with cathode located inside anode. Cathode is made of a large number of radial gas nozzles arranged on central tubular mast which admits oxygen gas. The sharp endings of the nozzles along with a set of corona rings create the high electric field at the cathode required for formation of dense corona plume responsible for O 3 evolution. A model of coronal plasma generation and ozone production is presented. The plasma formation is strongly dependent on the electric field and temperature in side diode where a high electron density in a low temperature negative corona is suited for high ozone yields. These are established by suitable regulation of A-K gap, voltage, oxygen pressure, and cathodenozzle population. IntroductionOzone is a powerful disinfectant and oxidant important for purification of drinking water, room air, and environment [1,2]. So also it is used for fumigation and sterilization in operation theatres in hospitals, disinfecting food products to increase shelf life, ozone therapy [3], and many more important applications. Plasma route of ozone generation is highly efficient [1] than other routes such as ultraviolet method. This work discusses the important features of a high-voltage (HV) corona controlled plasma-ozone generator which is under development presently in Pillai's Institute of Information Technology, Engineering, Media Studies and Research (PIIT) New Panvel. Engineering details of this generator are described in present work. A model of corona plasma generation as well as that of ozone production is also described and results presented along with discussions. The generator so developed will be used in many of above various applications.The generator makes use a negative corona discharge formed over the surface of cathode (K) of plasma diode where cathode is raised to a high negative potential (-1 to -60 keV) with respect to anode cup (A). Molecular oxygen O 2 is admitted in the anode-cathode (A-K) gap region and O 2 is split into atomic radicals O -through collisions by electron emissions from cathode. Alongside the radicals combine with free molecules O 2 and form ozone (O 3 ) the allotrope. The process is illustrated below is reversible having half-lives of tens of minutes at the ambient temperature and reduces with increase in temperature.

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Nine-point simplified variable-mesh finite-difference formulations of Poisson's equation

Cited by 5 publications

References 0 publications

A model of the generation and transport of ozone in high-tension nozzle driven corona inside a novel diode

A model of the generation and transport of ozone in high-tension nozzle driven corona inside a novel diode

Modeling and characterization of field-enhanced corona discharge in ozone-generator diode

High-tension corona controlled ozone generator for environment protection

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