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How can I calculate equivalence ratio?

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Old   April 27, 2008, 21:10
Default How can I calculate equivalence ratio?
  #1
Duan J Q
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When simulate diesel engine, equivalence ratio is an important parameter. But how can I calculate it?

Can anybody tell me?

Thanks for any help you can give me.

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Old   April 29, 2008, 04:09
Default Re: How can I calculate equivalence ratio?
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Mac
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Equivalance ratio is the ratio of Air-fuel mixture (stoic) to the Air-fuel mixture (actual). Hope this helps - Mac.
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Old   April 29, 2008, 17:50
Default Re: How can I calculate equivalence ratio?
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Andrea
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As Mac said the equiv. ratio is air-to-fuel stoich / air-to-fuel actual...depending on the combustion model that you use you have different way to get the correct mass concentration to calculate the air-to-fuel ratio.
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Old   May 6, 2008, 02:51
Default Re: How can I calculate equivalence ratio?
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Duan J Q
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The model what I use are:

1 Turbulent flow model: standard К-ε

2 Droplet Break-Up Model: Reitz/Diwakar

3 Spray impingement model: Bai's

4 Ignition model: shell

I want to know only steam or liquid and steam reckon in fuel?

And when I calculate air, air is equal to subtract fuel from cell mass or O2+N2+CO2+H2O or O2/0.233 or some way else?

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Old   May 15, 2008, 18:23
Default Re: How can I calculate equivalence ratio?
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Andrea
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Use only the mass of fuel vapor and the mass of air...calculated by means of m_02/0.233
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Old   May 21, 2008, 02:44
Default Re: How can I calculate equivalence ratio?
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sankar
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Hi i too need to calclulate Equivalence ratio..The pecentage of exhaust gases and composition are given..The Stoichiometric A/F ratio is known but i dunno actual A/F ratio..Can i find out the equivalence ratio from chemical equations..could anyone help me
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Old   May 21, 2008, 02:44
Default Re: How can I calculate equivalence ratio?
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sankar
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Hi.. i too need to calclulate Equivalence ratio..The pecentage of exhaust gases and composition are given..The Stoichiometric A/F ratio is known but i dunno actual A/F ratio..Can i find out the equivalence ratio from chemical equations..could anyone help me
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Old   June 7, 2008, 12:40
Default Re: How can I calculate equivalence ratio?
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Andrea
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You must calculate the actual A/F ratio from the output of your simulation...?!
Use command getc to load the mass of fuel vapour in each cell and to load the mass of oxygen in the same cells. Then you can calculate the locale A/F ratio and the local equiv. ratio.
Bye
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