[ibrahimtas]

Hello everyone,
With Converge CFD, I am working on the combustion analysis of a diesel engine as a closed cycle. In other words, I am working for the case where the valves are closed.

I am trying to overlap the CFD results with the in-cylinder pressure graph at the time of compression, but I could not get it to overlap as I wanted.


I checked my compression ratio for this.

I even reduced the compression ratio to the effective compression ratio.

Still no overlap occurred.

While doing research for this, I learnt that specific volume and specific pressure values are effective.

However, I do not know how to change these values, is there anyone who can help me with this?

Translated with DeepL.com (free version)

[drowinsk]

Hello and thank you for your question. When comparing the pressure trace, we recommend these steps:

1. Make sure to match the initial (after the timing of the last valve closure): composition, temperature, pressure, and volume
2. During closed cycle of compression, if your pressure trace deviates from the expectation, the possibilities are: incorrect volume change (determined by the initial volume and the volume change over time), incorrect initial condition, other loss mechanisms (leakage, heat transfer) which are usually minimal. In correct volume change may also be due to a mismatch between the crank angle in the simulation and the definition of the crank angle / position position relationship from the plot you are comparing to.

Feel free to let us know directly via our support email: support@convergecfd.com, if you have tried the above and still have any other questions.

Best regards,
David

[ibrahimtas]

Hello, David,
Thank you very much for your reply, I will repeat the analysis in the light of your suggestions.

Best regards