(Gaseous) Diesel type Engine

[Thamarai Kannan]

Dear All,

I am trying to make HCCI Engine simulation. I used https://cantera.org/examples/python/reactors/ic_engine.py.html as reference. I have modified engine specifications along with fuel. I was able to run my python code but the results are not reasonable.  For example, As per my theoretical  calculations I am should get 50 bar peak pressure but in this simulation I'm getting only 28 bar pressure. The results are not even close. I have attached my python code and pressure curve for your reference. It would be greatly if anyone tell me what is the problem and how can I get reasonable result. Thank you.

Kind Regards,

Thamarai kannan M

[Ingmar Schoegl]

Hi Thamarai,

Looking at your pressure/temperature curves it appears that your reactants are not igniting close to TDC. This could be related to either your mechanism or the fact that canters' 0D engine model is drastically simplified. In order to get HCCI right, you are relying on ignition delays at peak compression to be 'just right'. Please also note that the example doesn't assume HCCI - it simulates fuel injection of a reactive fuel close to TDC, where instantaneous perfect mixing is assumed.

One thing that is clearly not a good assumption is to use GRI-30 for methanol combustion: as this mechanism was developed for natural gas combustion, it's likely not a sufficiently accurate model for your purposes. For future references, please do not attach files without extension, as it wasn't clear that MethanolHCCI was a *.py file (if you need to rename, it's better to change to *.txt).

Hope this helps,

-ingmar-

[Thamarai Kannan]

Hi Ingmar,

Thanks for your response. So Ignition is not happening at right time. Let me check it.

Regarding GRI-30 mechanism I tried this with Methane as well yet the results are same.  Also I have a doubt, is the fuel used in CANTERA should always be gas or can we also use Diesel/Bio Diesel. If its possible can you give with any example.

Thank you,

Thamarai Kannan

[Ingmar Schoegl]

Dear Thamarai,

For methane etc, you need to use higher compression ratios as conditions are otherwise not conducive to auto-ignition. As an aside, GRI-30 is quite dated at this point, so it really should't be used for research purposes (although it's probably ok for some simple preliminary testing). Beyond, it is currently not easy to implement vaporization of liquids (see various threads on this user group) - for most reactor models, the reacting phase is modeled assuming an ideal gas.

-ingmar-

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[Thamarai Kannan]

Dear Ingmar,

Thank yo so much for clarifying my doubts.

Regards,

Thamarai Kannan M

[Thamarai Kannan]

Hi,

I ran the simulation similar to https://cantera.org/examples/python/reactors/ic_engine.py.html with Methane as fuel and compression ratio of 50.5. And I noticed that there is slight increase in the cylinder mass in the middle of combustion   and there is a  abnormal temperature variation. Can any one tell me why it is happening. I have attached the figures for your reference. 

Thank You,

Kind Regards,

Thamarai Kannan M

[Thamarai Kannan]

HI,

I found the answer for Cylinder mass. But still not get why the abnormal temperature variation. If anyone knows kindly help me in this. 

Thanks,

Thamarai kannnan M