thesis
The research and development of in situ non-intrusive optical and temperature diagnostics in an internal combustion engine
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Abstract
Novel instrumentation has been developed and evaluated in a low-cost, purpose built,
single-cylinder internal combustion engine test facility designed to simulate many of
the combustion features that are common between an internal combustion engine, a
gas turbine combustor and a steel rolling furnace. High bandwidth in-cylinder surface
temperature measurements are demonstrated with a new application of platinum thin
film resistance thermometers. These gauges are exposed to the combustion gases and
are mounted to both the cylinder head and piston. It is shown that calculation of flame
speed, determination of heat flux levels and flame structure observation are possible.
Fibre optic probes capable of high frequency spectral measurements of the
combustion emission are presented. The spectral measurements are shown to
complement the temperature measurement by being able to differentiate the flame
front from the general combustion emission and hot by-products. Beyond this, other
optical techniques have been explored in order to gain an understanding of the flame
front and flow within the combustion chamber. The novel spark plug described is
capable of combustion imaging and its application to in-cylinder PIV and flow
visualisation is demonstrated. Combustion modelling has been undertaken using
published engine models and a comparison between measured and predicted values of
pressure and heat flux is provided as a validation of the in-cylinder heat flux
measurements