# Who can help me about equivalence ratio?

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 May 8, 2008, 04:13 Who can help me about equivalence ratio? #1 Duan J Q Guest   Posts: n/a How can I calculate equivalence ratio? I use the models as following: Turbulent flow model: standard К-ε Droplet Break-Up Model: Reitz/Diwakar Spray impingement model: Bai's Ignition model: shell When I calculate equivalence ratio, is fuel reckon in only steam or liquid and steam? And air is subtract fuel from cell mass or O2+N2+CO2+H2O or O2/0.233 or some way else? Thank you for your advice.

 May 8, 2008, 11:36 Re: Who can help me about equivalence ratio? #2 Pauli Guest   Posts: n/a You posted the question previously. What information was lacking in those answers? Do you not know the definition of the equivalence ratio? Or do you have a problem with the mechanics of the calculations?

 May 8, 2008, 20:40 Re: Who can help me about equivalence ratio? #3 Duan J Q Guest   Posts: n/a Dear Pauli: I want to get the distribution of equivalence ratio. And I know the equivalence ratio is stoichiometric air-fuel ratio devided by actual air-fuel ratio. As I know it is possible to insert a formula and link it to scalars, but how to define air for actual air-fuel ratio, because if I link it to scalars, in the output the program only gives oxygen，nitrogen, carbon dioxide and water vapor, but how to define air? In my model, fuel is injected as liquid. When the combustion occurs, there are still many droplets in my model, but how to define fuel for actual air-fuel ratio? Should I reckon droplets in fuel? Thank you very much.

 May 9, 2008, 14:30 Re: Who can help me about equivalence ratio? #4 Pauli Guest   Posts: n/a To some extent, it depends what you are after. In the calculation, fuel vapor is reacted with oxygen. So rewrite your equivalence ratio in terms of fuel vapor & oxygen. Do not include the fuel liquid or the nitrogen.

 May 10, 2008, 00:38 Re: Who can help me about equivalence ratio? #5 Duan J Q Guest   Posts: n/a Thank you

 May 15, 2008, 18:17 Re: Who can help me about equivalence ratio? #6 Andrea Guest   Posts: n/a I think that you can define an "equivalence ratio" in term of oxygen and fuel vapor but that way you get something that is not comparable with the classic definition of EQUIV. RATIO. I suggest you to refer to the mass of air instead of the mass of oxygen...simply by means of m_air=m_O2/0.233 as you said. Then refer to the mass of fuel vapor for the computation of the equivalence ratio...only this way you get the standard "equivalence ratio" comparable with the correct definition.

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Duan J Q Siemens 7 June 7, 2008 12:40 usker Siemens 12 March 1, 2008 07:09 Antony Siemens 1 November 18, 2005 11:59 Mahbub Siemens 3 January 5, 2004 01:47 Amadou Sowe Main CFD Forum 4 November 4, 1999 14:32

All times are GMT -4. The time now is 22:54.

 Contact Us - CFD Online - Privacy Statement - Top