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Old   February 13, 2013, 07:51
Default Hydrogen-Air mixture ignition
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Hi everyone!

I'm doing PhD in hydrogen safety. At the moment I'm trying to reproduce one phenomenon which is connected to hydrogen deflagration in air with different concentrations.

My problem is that I can't ignite mixture with what ever concentrations (tried from 4.5-30% v/v):
In previous simulations for jet-fire I used k-e RNG for turbulence with EDC and chemkin 18 reactions mechanism for combustion with incompressible case implicit scheme, ignition was realized by patching high temperature in release zone with concentrations close to stoichiometric and it worked well without any complaints.
But that was for jet release, now it is still mixture, I switched to compressible case and tried lots of options to model deflagration, such as:
k-e RNG, EDC 18 reactions (implicit and explicit), ignition (hot zone and energy source term by UDF)
LES (RNG and Smagorinski-Lily), EDC 18 reactions (implicit and explicit), ignition (hot zone and energy source term by UDF)
In all those options tried to change solution methods and rate of temperature and source term increasing.
The result is the same for all cases: in the patching zone (zone where energy source term or high temp applied) hydrogen vanishes and substituted by oxygen, no reaction occurs (even small traces of oh h2o or whatever).
Could you please give me a piece of advise how deal with it because this is my first experience with compressible case.

Thank you in anticipation!
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