Week 10: Project 1 - FULL HYDRO case set up (PFI)
Aim
To simulate a Full Hydro Simulation in a Port Fuel Injection Engine.
Geometry
Above is the geometry of the port fuel injection engine and the cut plane view of the geometry showing the mesh.
Regions
Below are the four regions in the simulation. In the regions Temperature,Pressure, Turbulent Kinetic Energy and Turbulent disspication.
- Cylinder
- Intake System
- Exhaust System
- Intake System 2
Adaptive Mesh Refinement
Velocity AMR
For the velocity AMR the embedding level is set 3 and SGS to 1 m/s. So the size for this embedding will be calculated by
`Grid Size = (Base Grid)/2^(Embed Level)`
=0.004/2^3
=0.0005 m
This AMR will take place whenever the set SGS level is reached and greater than it.
Temperature AMR
Similarly to the Velocity AMR the Temperature AMR has an embed level of 2 with SGS of 2.5 K. The refinment will take place whenever the 2.5 K SGS parameter or greater is achieved.
`Grid Size = (Base Grid)/2^(Embed Level)`
=0.004/2^3
=0.0005 m
Fixed Embedding
- Cylinder
Here the embedding will be permanent.
`Grid Size = (Base Grid)/2^(Embed Level)`
= 0.004/2^2
=0.001 m
- Intake Valve Angle
Here the embedding will be permanent with layer of 2.
`Grid Size = (Base Grid)/2^(Embed Level)`
= 0.004/2^3
=0.0005 m.
- Exhaust Valve Angle
Here the embedding will be permanent with layer of 2.
`Grid Size = (Base Grid)/2^(Embed Level)`
= 0.004/2^2
=0.001 m
- Sphere
Here the embedding is cyclic starting at -16 deg to 0 deg. This embedding is for the spark production.
`Grid Size = (Base Grid)/2^(Embed Level)`
= 0.004/2^4
=0.00025 m
- Sphere
Here the embedding is cyclic starting at -16 deg to 0 deg. This embedding is for the spark production.
`Grid Size = (Base Grid)/2^(Embed Level)`
= 0.004/2^5
=0.000125 m
- Injector
Here the embedding is cyclic starting at -485 deg to -265 deg. This embedding is for the injector.
`Grid Size = (Base Grid)/2^(Embed Level)`
= 0.004/2^4
=0.00025 m.
Engine Performance
Con.Rod = 0.18 m
Stroke = 0.09 m
Bore =0.086 m
RPM = 3000.
Power
Power=Work Done/ Time Taken
Time taken = Time Taken per deg *(60/360*RPM)
=640.11*(60/360*3000)
=0.03556 sec
Power= 468.646/0.03556
Power= 13,179 W or 13.179 KW
Torque=`(60000*Power)/(2*Pi*RPM)`
= 60000*13.179/2*Pi*3000
Torque = 41.950 N-m
Combustion Efficiency
`eta _(com)= (Heat Rel ease)/ (Mass of fuel * LHV of fuel)`
=1241.11/(3*10^-5*44.651*10^6)
`eta_(com)`=0.926526 or 92.6526%
Compression Ratio
or
Compression ratio Calculation by Volume
Compression Ratio = Vmax/ Vmin
=0.000574219/5.70359e^-5
Compression Ratio= 10.06767.
Pressure
The according the pressure plot the pressure reached around 3.88 MPa during the combustion process.The pressure is also gradual increase without any distortation.
Temperature
When looking at the temperature plot the temperature change is not gradual but during the combustion process the temperature is around 2488 K in the combustion chamber meaning a complete combustion has taken place.
Emissions
NOx
After the combustion process exhaust gases are produed. Nox is typically produced around high temperatures about 1800 K. Here we can see that the temperature reached around 2500 K so Nox is produced but in a small amount when compared to other gases like HC and CO. NOx produced in this reaction is 1.36966e-6 Kg/cycle.
Carbononoxide
The CO production in SI engine is usually beacuse air/fuel ratio. When there is insuffuicient oxygen in the chamber during combustion then CO is produced , this is beacuse of incomplete combustion.
Wall Heat Transfer Model Needs
The wall Heat transfer is uesd when there is an interaction with the soild walls and the fluid regions in the system. But for this simulation we did not assign an solid interface, we use only the Navier stokes and the scalar transport equations which is used for the fluids.
Significanes of CA10,CA50 and CA90
CA 10 refers to in which the combustion takes place in 10%. CA50 refers to the combustion takes place in 50%. CA90 refers to the combustion takes place in 90%. These usually determines the ignition timing,valve opening and closing squencing, and fuel delivery.
Animation