Hydrogen fire + another fuel fire

[Jose del Solar]

Hi, I am trying to create two different combustion processes in a tunnel. One of them uses a complex fuel molecule, and the other is a hydrogen fire. I tried to use the lumped species approach as recommended in Section 15.2.4 of the user guide (Multiple Fuels). My input lines are as follows:

&SPEC ID = 'CARB',FORMULA='C1.0H1.8O0.3N2.0Cl0.106326S0.003364' /

&SPEC ID = 'AIR', SPEC_ID(1)='OXYGEN', SPEC_ID(2)='NITROGEN', VOLUME_FRACTION=1.000000,3.761905, BACKGROUND=.TRUE. /

&SPEC ID = 'HYDROGEN'/


&SPEC ID = 'OXYGEN', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'NITROGEN', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'CARBON DIOXIDE', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'WATER VAPOR', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'CARBON MONOXIDE', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'SOOT',FORMULA='C', LUMPED_COMPONENT_ONLY = .TRUE., MASS_EXTINCTION_COEFFICIENT = 8700.0 /
&SPEC ID = 'HYDROGEN CYANIDE', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'HYDROGEN CHLORIDE', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'SULFUR DIOXIDE', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'ACROLEIN', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'FORMALDEHYDE', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'ACETALDEHYDE', LUMPED_COMPONENT_ONLY = .TRUE. /
&SPEC ID = 'NITRIC OXIDE', LUMPED_COMPONENT_ONLY = .TRUE. /

&SPEC ID = 'PRODUCTS',
SPEC_ID(1)='CARBON DIOXIDE',SPEC_ID(2)='WATER VAPOR',SPEC_ID(3)='NITROGEN',
SPEC_ID(4)='CARBON MONOXIDE',SPEC_ID(5)='SOOT',
SPEC_ID(6)='HYDROGEN CYANIDE',SPEC_ID(7)='HYDROGEN CHLORIDE',
SPEC_ID(8)='SULFUR DIOXIDE',SPEC_ID(9)='ACROLEIN',SPEC_ID(10)='FORMALDEHYDE',
SPEC_ID(11)='ACETALDEHYDE',SPEC_ID(12)='NITRIC OXIDE',
VOLUME_FRACTION =
0.600818, 0.842387, 4.568149,
0.143816, 0.249409,
0.002551, 0.106326,
0.003364, 0.000231, 0.001579,
0.000567, 0.000989/

&SPEC ID = 'PRODUCTS_2',
SPEC_ID(1)='WATER VAPOR',SPEC_ID(2)='NITROGEN',
VOLUME_FRACTION =
1, 1.880953/

&REAC ID                 = 'CARXYZ'
      FUEL               = 'CARB'
      HEAT_OF_COMBUSTION = 31400.0
      SPEC_ID_NU         = 'CARB','AIR','PRODUCTS'
      NU                 = -1.0,-0.948966,1.0
      RADIATIVE_FRACTION = 0.3 /
 
&REAC ID                 = 'HYD'
      FUEL               = 'HYDROGEN'
      HEAT_OF_COMBUSTION = 141790.0
      SPEC_ID_NU         = 'HYDROGEN','AIR','PRODUCTS_2'
      NU                 = -1.0,-0.5,1.0
      RADIATIVE_FRACTION = 0.2 / SFPE 5th ed, Table 66.14  
 
&SURF ID='FIRE',SPEC_ID = 'CARB',MASS_FLUX=0.3185, RGB=255,0,0, RAMP_MF='RAMP_FIRE' / 10 MW, medium growth
&SURF ID='LEAKSURF', SPEC_ID='HYDROGEN', MASS_FLUX=0.015, TMP_FRONT=30/

I am getting the following error message:

ERROR: MIXTURE FRACTION requires one and only one REAC input

Is it possible to have these two reactions going at the same time in FDS? The section on Multiple Fuels in the User's Manual gives an example for two complex molecules (polyurethane and wood), so  I would assume having a complex fuel and a more simple hydrogen combustion reaction would also be possible. Is there any way to approach this?

[dr_jfloyd]

That is not a complete input file (no MESH, TIME, outputs, etc.). The error message is indicating that you have some output (SLCF, DEVC, etc.) with QUANTITY='MIXTURE FRACTION'.  You can have multiple REAC, but the mixture fraction can only be output if you have a single reaction. 

[No Name]

Thank you. You just figured  out what the problem was. I had previously defined a “MIXTURE FRACTION” in the file. 

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