الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
 |  | from | 136 |  |  |
| | | from | 136 | | |
Abstract
The corona discharge at high-voltage electrodes is considered one
of the common methods for generation of ozone, being used in many
applications in industry, agriculture, medicine, etc. This thesis work is
aimed at calculating the electric field around a stressed wire extending
along the axis of a grounded meshed cylinder. Following the field
calculation, the onset voltage of negative corona in wire-meshed cylinder
configuration is calculated. With the increase of the applied voltage
above the onset value, the corona current increases with a subsequent
increase of ozone generation. The use of meshed cylinder makes it
possible to assess the ozone generation using ozone meters positioned
outside the cylinder without disturbing the electric field in the interelectrode
spacing
between
the
wire
and
cylinder.
The method of field calculation is based on the well-known charge
simulation technique. In wire-solid cylinder configuration, both the wire
and cylinder are simulated by ring charges. In wire-meshed cylinder
configuration, the wire is simulated by finite line charges and the cylinder
is simulated by ring charges and finite line charges. The electric field is
calculated for different values of the configuration length, wire length,
wire radius and mesh size. The calculated electric field values near the
stressed wire (about 20% of the gap spacing) are higher for wire-meshed
cylinder in comparison with those of wire-solid cylinder configuration
with different mesh sizes at varying values of wire radius and
configuration length. The calculated electric field values at radial distance
in range of 20-85% and more of the inter electrode gap spacing are
smaller for wire-meshed cylinder in comparison with wire-solid cylinder
configuration.
Corona onset voltage is evaluated based on the calculated field
values and the criterion for self-recurring single electron avalanches in the
ionization-zone around the wire surface. The calculated onset voltage
values are compared and agreed favorably within 10% of the present
measured values 15% of those reported in the literature by other
investigators. The calculated and measured corona onset voltage values
for meshed cylinder are smaller than those of the solid cylinder
irrespective of wire radius. The calculated onset voltage values agreed
reasonably with those measured experimentally. The corona currentvoltage
(I-V)
characteristics
are
measured
for
a
laboratory
model
of
wiresolid
cylinder
and
wire-meshed cylinder configurations. Even the corona
onset voltage for wire-meshed cylinder configuration is smaller than that
of the wire-solid cylinder case, the corona current is higher for the wiresolid
cylinder case because of the higher prevailing electric field along
most of the flux lines where the corona ions convect toward the outer
cylinder.