[jr_3]

Hi Everybody,
Pretty broad CFD question coming up...
In about 2 months of research into combustion CFD, I've seen plenty of studies that use a 2D axisymmetric (wedge) mesh to simulate compression ignition but zero studies using this type of engine geometry for Spark Ignited cases. I get that axisymmetric cases are highly idealized and that there isn't a whole lot of symmetry in spark engines but are there any other arguments out there for or against 2D gasoline CFD simulations, apart from those two intuitions?

Thanks in advance.

[Sarang V]

Compression ignition

A sector approach is usually preferred for diesel combustion simulations because of the way fuel is injected. If you have a 6 hole multi-nozzle injector you could create a sector of 60 degrees. The sides of the sector mesh are assigned periodic boundary condition and not a symmetry BC.

Spark Ignition

1. The entire engine is modelled because the flame front is not symmetric (due to non-homogeneities in fuel composition and turbulence quantities).

2. It is extremely important to capture TKE to get the flame propagation correctly (at-least while using detailed chemical kinetics). This can be achieved only if you simulate the intake stroke (full engine geometry).