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April 27, 2008, 21:10 
How can I calculate equivalence ratio?

#1 
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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. 

April 29, 2008, 04:09 
Re: How can I calculate equivalence ratio?

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Equivalance ratio is the ratio of Airfuel mixture (stoic) to the Airfuel mixture (actual). Hope this helps  Mac.


April 29, 2008, 17:50 
Re: How can I calculate equivalence ratio?

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As Mac said the equiv. ratio is airtofuel stoich / airtofuel actual...depending on the combustion model that you use you have different way to get the correct mass concentration to calculate the airtofuel ratio.


May 6, 2008, 02:51 
Re: How can I calculate equivalence ratio?

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The model what I use are:
1 Turbulent flow model: standard Кε 2 Droplet BreakUp 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? 

May 15, 2008, 18:23 
Re: How can I calculate equivalence ratio?

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Use only the mass of fuel vapor and the mass of air...calculated by means of m_02/0.233


May 21, 2008, 02:44 
Re: How can I calculate equivalence ratio?

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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


May 21, 2008, 02:44 
Re: How can I calculate equivalence ratio?

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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


June 7, 2008, 12:40 
Re: How can I calculate equivalence ratio?

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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 

May 29, 2022, 12:01 

#9 
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Equivalence ratio() = Actual airfuel ratio/stoichiometric airfuel ratio
you can see more details about equivalence ratio here you can calculate stoichiometric airfuel ratio by balancing chemical reaction of fuel with oxidizer or it can be also calculated from elemental composition of fuel. You can also use online calculators like this. 

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