
[Sponsors] 
December 15, 2009, 10:29 
Rich Flammability Limit

#1 
New Member
Johann V
Join Date: Oct 2009
Posts: 19
Rep Power: 10 
Hi everybody,
I hope someone can help me with my problem. Thanking you in anticipation. I need to calculate a combustion model (non premixed combustion PDF) and therefore I need the Rich Flammability Limit (RFL). There are, one fuel stream (CH4 85%, N2 11%, C3H8 4%), one oxidiser (O2 100%), and an ambient air stream. I read in the FLUENT documentation that the RFL for the ambient stream can be set to 1. But what do I do with the RFL for the fuel stream? Is this the same as the Lower Explosive Limit (LEL)? 

December 16, 2009, 04:49 

#2 
New Member
Johann V
Join Date: Oct 2009
Posts: 19
Rep Power: 10 
Good morning friends of CFD.
I yust calculated the rich limit as folows. f=(Z_iZ_i_oxi)/(Z_i_fuelZ_i_oxi) Z_i : mass fraction of (CH4 + C3H8) in respect to the Lower Explosive Limits. Z_i_fuel : mass fraction of (CH4 + C3H8) in the fuel Z_i_oxi : mass fraction of (CH4 + C3H8) in the oxidizer All values were calculated for a volume of 1 m^3. And the result is f=0.03 Is this result reasonable? Any hint and sugestion is velcome. 

August 25, 2010, 23:12 

#3  
New Member
Dong Liang
Join Date: Jan 2010
Location: Shanghai, China
Posts: 12
Rep Power: 9 
Quote:
the f is the mixture fraction. Z_i is the mass fraction of i element, like C, H, O, etc. the result is only one with any element in the system. the RFL is a constant that the fluent will compute the chemistry when the f is above it. in most cases, it will be larger than chemical equivalent. 

Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
how to increase "Newton Pressure Iteration Limit"  kus  CFX  9  April 21, 2013 01:54 
limit holdup value  mohini  CFX  2  July 31, 2008 03:58 
How to limit a variable  ash  OpenFOAM Running, Solving & CFD  1  June 26, 2008 20:32 
mesh adaption memory limit  Dave  FLUENT  1  March 27, 2004 10:02 
Data size limit  Kaokanya  Siemens  2  January 6, 2004 09:32 