A Numerical Study of Reacting Flows Using Finite Rate Chemistry
Doctoral thesis, 2012
Fossil fuels will remain the main source of energy for mankind in the
foreseeable future. Heat released in combustion of fossil fuels is always
accompanied by emission of undesired pollutants. Environmental concerns
have led to stringent emission rules for combustion industry specially
for reducing the amount of NOx production. Lean premixed combustion
has increasingly gained interest in recent years as an approach
toward reduced NOx emissions by reducing the operating temperature.
However, lean blow off limit and the tendency of the dynamic flame to
become unstable present technical challenges. The low swirl burner
concept is a rather new and promising design to stabilize lean premixed
flames close to their flammability limit. Large Eddy Simulation
together with a finite rate chemistry combustion model have been used
here for numerical studies of a laboratory low swirl stabilized flame.
The importance of the inlet boundary condition is investigated and an
optimized approach is suggested. The flame stabilization mechanism
is discussed and it is shown that the choice of the inlet boundary condition
can significantly affect this mechanism.
Air transport is becoming more common and aviation contribution
to anthropogenic CO2 production will soon become prominent. Turbomachinery
efficiency in modern aircraft engines is close to perfection
and innovative core designs are needed for significant efficiency improvements.
Unsteady phenomena in the working cycle of a conceptual
Pulse Detonation Engine is studied here using URANS and a finite rate
chemistry combustion model. The limitations imposed by the unsteady
flow at compressor side are compared for two alternative engine configurations
Lean blow off
Finite rate chemistry
Inlet boundary condition
Pulse Detonation Engine
Low Swirl Burner
Large Eddy Simulation