Week 11: Project 2 - Emission characterization on a CAT3410 engine
Aim - To do study the two different type of pistons omega and open w type pistons.
Our objective is to- 1. Run simulations with both these pistons
- Characterize the emissions (Soot, Nox and UHC)
- Compare the imep and power values graphically.
Geometry Set up –
1.Import the geometry in converge software. In this we will generate Engine sector surface from complete 360 geometry of piston.
2.Go to tools – Click on make engine sector surface – Enter engine parameters as shown below pictures. Imports the bowl profile.
3.In this we will be studying 2 type of pistons omega and open W Piston.
4.For both pistons the surface geometry is shown below.
Open W piston confriguration -
Open W piston Surface geometry
Omega piston confriguration -
Omega piston Surface geometry
After case set up exports the file to defined folder. Run the simulation in the Cygwin. Generate the output files. As output file is generated run the post processing in Cygwin again. Open the output file in paraview for the mesh view and simulation
Outputs –
Mesh – Omega piston
Open W piston -
Presssure –
From pressure plot is indicated that the inside pressure cylinder for open w type is slight higher than omega piston.
Temprature
From temperature plot of omega it is shown that mean temperature is higher than open w type of piston .
Integrated HR –
Integrated heat release is total energy release during the combustion process. For omega piston it is high .
Heat release –
Heat release to surrounding is very much higher for omega piston than open w piston type.
Nox –
As from temperature graph we seen for omega it was high so it will lead to high nox due to high cylinder temperature . Nox value is also affected with lambda. In omega mixture is lean that why it lead to high nox.
HC-
As in omega nox level is high so there will be less hc emission . because mixture is lean in case of omega piston. And open w will have more hc content because mixture is rich .
CO –
Due to unburnt fuel in the open w piston the co value is high .
SOOT –
Unburnt fuel in the open w piston lead to more soot in exhaust it is clear from the soot graph.
IMEP and Power calculation for Open w piston –
Imep – 1.24 x 10^6 pa
Work done – 3028.53 NM
Duration- 282.017 degree
Crank speed – 1600
Degree / sec- 1600/60 X360 = 9600 DEG/SEC
Time for combustion – 282.017/9600 = .0293se
Power = W.D / Time = 3028.53 / .0293 = 103.362 kw
IMEP and Power calculation for Omega piston –
Imep – 1.396 x 10 ^6 pa
Work done- 3409.28 nm
Duration- 282.0029 degree
Crank speed – 1600
Degree / sec- 1600/60 X360 = 9600 DEG/SEC
Time for combustion – 282.0029/9600 = .02937se
Power = W.D / Time = 3409.28 / .02937 = 116.08 kw
Conclusion – It is seen that for given configuration the omega piston gives good results. High Power is achieved in omega piston with less co and hc emission. The fuel atomization and burning is far better than open w type piston. NOX is only drawback with omega which can we minimized with with scr aftertreatment method.
Animation links -