Spatial distributions of OH (top) and soot particles (bottom) at
different crank angle degrees after top dead centre. The centre axis is
the cyclic boundary. Yellow, green and blue colours indicate high,
intermediate and low species concentrations,
respectively.
Large two-stroke
marine diesel engines dominate as prime movers for cargo ships due to
their high efficiency and reliability. In 2016, the International
Maritime Organisation has enforced new regulations
for marine engines, with the aim to reduce emitted pollutants for
instance, to reduce the nitric oxides by 80%. Producing engines for low
emission limits without lowering the fuel efficiency is a challenging
task. Indeed, both fuel efficiency and formation
of emissions are strongly dependent on the combustion characteristics,
which is a result of fuel spray development such as droplet breakup,
evaporation and mixing with air. Meanwhile, the scavenging flow plays a
significant role in influencing the aforementioned
processes. Integration model of three-dimensional CFD and chemical
kinetics is hereby used to provide a better understanding and gain
insights of the in-cylinder events. A skeletal chemical mechanism is
developed, of which is computationally efficient for three-dimensional large
bore marine engine simulations yet sufficiently comprehensive to
include species essential for pollutant formation predictions. By
incorporating the in-house chemical mechanism and turbulence/velocity
fields obtained from scavenge flow simulations,
development of a heavily sooting diesel flame and the heat transfer
process under large, two-stroke marine diesel engine-like conditions are
investigated.
- Sigurdsson, E., Ingvorsen, K. M., Jensen, M. V., Mayer, S., Matlok, S. and Walther, J. H., Numerical analysis of the scavenging flow and convective heat transfer in large two-stroke marine diesel engines, Applied Energy, 123, 37-46, 2014 (ORBIT Link).
- Pang, K. M., Karvounis, N., Walther, J. H., and Schramm, J., Numerical investigation of soot formation and oxidation processes under large two-stroke marine diesel-like conditions using integrated CFD-chemical kinetics, Applied Energy, 169, 874-887, 2016 (ORBIT Link).