This Thesis covers work conducted to understand the mechanisms
underpinning the operation of the electrothermal-chemical gun. The
initial formation of plasma from electrically exploding wires, through to
the development of plasma venting from the capillary and interacting
with a densely packed energetic propellant bed is included. The prime
purpose of the work has been the development and validation of
computer codes designed for the predictive modelling of the
elect rothe rmal-ch em ical (ETC) gun.
Two main discussions in this Thesis are:
a proposed electrically insulating vapour barrier located around
condensed exploding conductors and
the deposition of metallic vapour resulting in a high energy flux to
the surface of propellant, leading to propellant ignition.
The vapour barrier hypothesis is important in a number of fields where
the passage of current through condensed material or through plasma
is significant. The importance may arise from the need to disrupt the
fragments by applying strong magnetic fields (as in the disruption of
metallic shaped charge jets); in the requirement to generate a metallic
vapour efficiently from electrically exploding wires (as per ETC ignition systems); or in the necessity to re-use the condensed material after a
discharge (as with lightning divertor strips).
The ignition by metallic vapour deposition hypothesis relies on the
transfer of latent heat during condensation. It is important for the
efficient transfer of energy from an exploded wire (or other such
metallic vapour generating device) to the surface of energetic material.
This flux is obtained far more efficiently through condensation than
from radiative energy transfer, because the energy required to
evaporate copper is far less than that required to heat it to
temperatures at which significant radiative flux would be emitted
| Identifer | oai:union.ndltd.org:CRANFIELD1/oai:dspace.lib.cranfield.ac.uk:1826/4010 |
| Date | 24 November 2009 |
| Creators | Taylor, M J |
| Contributors | Crowley, Prof A |
| Publisher | Department of Environmental and Ordnance Systems |
| Source Sets | CRANFIELD1 |
| Language | English |
| Detected Language | English |
| Type | Thesis or dissertation, Doctoral, PhD |
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