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CUED Division A

Energy, Fluids and Turbomachinery

Wandel, Mastorakos, Cant, Swaminathan, Chakraborty (University of Liverpool)

Three-dimensional Direct Numerical Simulations with one-step chemistry
have been carried out in order to understand the spark ignition
phenomena in a non-homogeneous mixture. The effects of spark
energy and spark location for sustainable combustion are studied by
varying spark power, duration, and spark location in the mixture
fraction space.

Depending on the spark power and spark location,
one may encounter twin or triple flames in the present configuration
(see Fig.1).
The statistical behaviour of the edge flame propagation is
studied in terms of edge flame speed behaviour with respect to
scalar dissipation rate and local flame curvature. This study
eventually leads to the modelling of edge flame speed with respect to
the various parameters, namely, turbulence frequency, scalar
dissipation rate and flame curvature.
The present study will subsequently lead to the modelling attempt of
the ignition process using Conditional Moment Closure (CMC)

triple flame structure

Figure 1.  Typical
triple flame structure following a localised energy deposition at a
point with stoichiometric mixture, visualised by the magnitude of fuel
consumption rate at x-y plane at z = 0.5.
The spark location corresponds to x = y = z = 0.5. The white line shows
the stoichiometric mixture fraction contour.