[luckyboy]

Hello,
When the ignition time is too late(about 13CA BTDC), the cylinder pressure and temperature will increase sharply, and the heat relase rate is similar, as attments show. It seems that energy is released in an instant, which is unreasonable. Anyone can tell me why? I have suspected that there are some wrong with reaction mechanism, but it's useless to change another mechanism. And I plan to use the third one.
Thanks for your help!

[modism]

Hello My Friend.Today I meet the same question as you. Do you solve it?

[luckyboy]

Originally Posted by modism

Hello My Friend.Today I meet the same question as you. Do you solve it?

No, what fuel do you use? I used hydrigen as fuel! If you solve the problem, please tell me, and me too.

[tmburton]

Hello,

What reaction mechanism are you using for your hydrogen combustion? Most of the mechanisms we have looked at were tuned to experimental data that was heavily diluted, and we have found that using these mechanisms under non-diluted conditions can lead to detonations.

Best regards,

Tristan

[luckyboy]

Originally Posted by tmburton

Hello,

What reaction mechanism are you using for your hydrogen combustion? Most of the mechanisms we have looked at were tuned to experimental data that was heavily diluted, and we have found that using these mechanisms under non-diluted conditions can lead to detonations.

Best regards,

Tristan

Thanks for your reply! The attachment is what reaction mechanism I used. In my case, the equivalence ratio is about 0.52, which is enough lean I think. Do you think the detonation happens in my case? Is it normal? Can I say the mechanism is not suitable? And can you give me some suit mechanism?

[nitesh.attal]

Please look at the following (or similar) papers to determine the 1st-3rd explosion limits for your mixture. Also take into consideration that the energy you deposited resulted in max. temperature (~10,000K) where H2 is bound to detonate/explode. Also, is this a Hydrogen-Oxygen combustion or Hydrogen-Air?

Wang, Xianming, and Chung K. Law. "An analysis of the explosion limits of hydrogen-oxygen mixtures." The Journal of chemical physics 138.13 (2013): 134305-134305.

Thanks,

[luckyboy]

Originally Posted by nitesh.attal

Please look at the following (or similar) papers to determine the 1st-3rd explosion limits for your mixture. Also take into consideration that the energy you deposited resulted in max. temperature (~10,000K) where H2 is bound to detonate/explode. Also, is this a Hydrogen-Oxygen combustion or Hydrogen-Air?

Wang, Xianming, and Chung K. Law. "An analysis of the explosion limits of hydrogen-oxygen mixtures." The Journal of chemical physics 138.13 (2013): 134305-134305.

Thanks,

Thank you very much!

[YHY]

hi,
i met the problem that the combustion was very fast as yours, do you solve the problem? Is it the problem of mechanism？

[luckyboy]

I am reading the paper nitesh.attal recommended, you can also read it. What fuel do you use? hydrogen?

[YHY]

thanks for your reply, i use methanol. i will read the paper too.

Sent from my MI 6 using CFD Online Forum mobile app

[YHY]

hi, luckyboy
Do you solve your problem according to the paper above? i met the problem as long as i use the SAGE model. which combustion model do you use?

Sent from my MI 6 using CFD Online Forum mobile app

[luckyboy]

Originally Posted by YHY

hi, luckyboy
Do you solve your problem according to the paper above? i met the problem as long as i use the SAGE model. which combustion model do you use?

Sent from my MI 6 using CFD Online Forum mobile app

NO, but I am trying to make the mixture more diluted. The combustion model I use is SAGE. About the problem, I think all reaction mechanism is suitable under certain conditions.