Thesis-1975-Morris.pdf (29.89 MB)
The modelling of fuel dispersion and concentration in direct injection diesel engines
thesis
posted on 2011-02-04, 15:01 authored by Christopher J. MorrisThe presented investigation develops a modelling technique,
which allows measurement in a dynamically similar gas jet, to be related
to the diesel engine injection process in the presence of air swirl.
Modelling experiments have been performed for direct injection
processes from both the centre and the circumference of the combustion
chamber. A tracer gas technique has been employed, by which, concentration
of jet nozzle gas in the simulated air swirl was measured, thus
yielding information on model predicted trajectory, spread and local
fuel concentration. Gas concentration was measured using a specially
developed hot wire anemometry technique which allowed measurement in a
transient pulsed jet simulation.
The modelling theory was developed on the basis that spray droplet
velocity relative to the air entrained into the spray is small after
an initial jet disintegration, and droplet formation process. Consequently
the fuel spray is assumed to behave as an air jet bearing a mist of
liquid droplets.
Favourable comparison of model gas jet and engine fuel spray
behaviour is initially made with published film data. Further comparison
of engine performance and associated high speed photographic results,
with the model predicted fuel dispersion and local concentration levels,
is made from data obtained on a modified Petter PM test engine. The
results indicate that model predicted rich fuel regions, both at the
combustion chamber wall and within the Jet core correspond to smoke
generation areas recorded on the high speed films. Similarly, experimental
engine performance parameters such as exhaust emission levels' rate of pressure rise, and peak pressure are shown to directly relate to the
model predicted dispersion of fuel. The conclusions drawn are that the modelling technique has
potential in optimising the fuel injection equipment specification at
the design stage and effectively represents the behaviour of the modelled
engine fuel spray.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Publisher
© Chrisopher J. MorrisPublication date
1975Notes
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.466262Language
- en