Particle Image Velocimetry (PlY) is a technique for measuring instantaneous twodimensional
fluid velocity fields from a chosen plane of interest within a flow field.
This thesis presents new developments and applications of the technique which have
been used to study both the non-reacting and reacting flow fields within cylindrical
Non-reacting, swirling laminar flow fields near the transitional flow regime have been
investigated by both Computational Fluid Dynamics (CFD) modelling and PIV
experiments. Direct comparisons between CFD, PlY and other published results are
made and close agreements are found. Additionally, the PlY technique has been
optimised by careful use of a thin laser illumination sheet and correct choice of laser
pulse separation. This has enabled successful PlY measurements in the boundary layers
of the flow field where high velocity gradients exist.
The PlY technique has been applied to measure the flame development and propagation
process within the chamber under both quiescent and swirling flow conditions.
Representative sequences of PIV results at different flame propagation stages are
obtained and the accuracy in the extraction of the flame location is discussed. They
clearly reveal the instantaneous flame front position and the unburned gas velocity field
simultaneously. These features provide further insight into the combustion process itself
and also the interaction between the combustion and flow field.
A new application of PIV, combined with a flame speed detection technique, has been
proposed and developed to obtain direct measurements of the laminar burning velocity
of combustible mixtures. The laminar burning velocity is determined as the difference
between the flame speed and the unburned gas velocity immediately ahead of the flame
front. PIV is used to measure the unburned gas velocity field and either a pair of
ionisation probes or a laser beam refraction technique is used to measure the local flame
speed simultaneously. The relative merits of each technique are compared. The laminar
burning velocities of propane-air mixtures initially at atmospheric conditions for
equivalence ratios ranging from 0.7 - 1.4 were measured. The measured values show
close agreement with previously published results based on other techniques.
The advantages and limitations of the PIV techniques used in this work are examined and the prospects of their improvement and further application are discussed.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.