I set my own fuel and used propane for ignition, but I couldn't achieve it

[yswwyx]

My program is as follows:

&HEAD CHID='CLC'/
&TIME T_END=30/
&DUMP DT_HRR=0.1, DT_BNDF = 1/
&MISC TMPA=20. /
&MESH ID='Mesh01', IJK=70,40,80, XB=0.0,7.0,-2.0,2.0,0.0,8.0/

&SPEC ID='OXYGEN',LUMPED_COMPONENT_ONLY=F/
&SPEC ID='CARBON MONOXIDE',LUMPED_COMPONENT_ONLY=T/
&SPEC ID='CARBON DIOXIDE',LUMPED_COMPONENT_ONLY=T/
&SPEC ID='NITRIC OXIDE',LUMPED_COMPONENT_ONLY=T/
&SPEC ID='NITROGEN DIOXIDE',LUMPED_COMPONENT_ONLY=T/
&SPEC ID='HYDROGEN FLUORIDE',LUMPED_COMPONENT_ONLY=T/
&SPEC ID='HYDROGEN CHLORIDE',LUMPED_COMPONENT_ONLY=T/
&SPEC ID='HYDROGEN CYANIDE',LUMPED_COMPONENT_ONLY=T/
&SPEC ID='SOOT',LUMPED_COMPONENT_ONLY=T/
&SPEC ID='BEV', FORMULA='C81.463H0.737N0.182F0.389Cl0.322'/
&SPEC ID='PROPANE'/
&SPEC ID='PRODUCT',SPEC_ID(1)='CARBON DIOXIDE', VOLUME_FRACTION(1)=68.627,
SPEC_ID(2)='CARBON MONOXIDE', VOLUME_FRACTION(2)=2.27,
SPEC_ID(3)='NITRIC OXIDE', VOLUME_FRACTION(3)=0.125,
SPEC_ID(4)='NITROGEN DIOXIDE', VOLUME_FRACTION(4)=0.031,
SPEC_ID(5)='HYDROGEN FLUORIDE', VOLUME_FRACTION(5)=0.389,
SPEC_ID(6)='HYDROGEN CHLORIDE', VOLUME_FRACTION(6)=0.322,
SPEC_ID(7)='HYDROGEN CYANIDE', VOLUME_FRACTION(7)=0.026,
SPEC_ID(8)='SOOT', VOLUME_FRACTION(8)=10.54,/
&REAC ID='B_1'
FUEL ='BEV',
HEAT_OF_COMBUSTION = 43000,
SPEC_ID_NU='BEV','OXYGEN','PRODUCT',
NU=-1,-69.8555,1,/
&REAC ID='P_1',
FUEL = 'PROPANE',/

&MATL ID='DX_BEV',
DENSITY=1000,
SPEC_ID='BEV',
SPECIFIC_HEAT=1.06,
CONDUCTIVITY=0.45,
HEAT_OF_COMBUSTION = 43000,
EMISSIVITY=0.9/
&SURF ID='BEV_MT',
COLOR='GRAY 80',
SPEC_ID='BEV',
MATL_ID = 'DX_BEV',
IGNITION_TEMPERATURE=171,
THICKNESS=1/

&SURF ID='FIRE',HRRPUA = 100,SPEC_ID='PROPANE',TAU_Q=0/

&VENT MB = 'XMIN', SURF_ID = 'OPEN',TMP_EXTERIOR = 20/
&VENT MB = 'YMIN', SURF_ID = 'OPEN',TMP_EXTERIOR = 20/
&VENT MB = 'XMAX', SURF_ID = 'OPEN',TMP_EXTERIOR = 20/
&VENT MB = 'YMAX', SURF_ID = 'OPEN',TMP_EXTERIOR = 20/
&VENT MB = 'ZMAX', SURF_ID = 'OPEN',TMP_EXTERIOR = 20/

&OBST ID='CHE1', XB=1.4,2.8,-0.9,0.9,0.2,1.1, SURF_ID6='BEV_MT',,'BEV_MT','BEV_MT','BEV_MT','BEV_MT'/
&OBST ID='CHE2', XB=5.2,5.6,-0.9,0.9,0.2,1.1, SURF_ID6=,'BEV_MT','BEV_MT','BEV_MT','BEV_MT','BEV_MT'/
&OBST ID='CHE3', XB=2.8,5.2,-0.9,0.9,1.1,1.6, SURF_IDS='BEV_MT','BEV_MT',/
&OBST ID='CHE4', XB=2.8,5.2,-0.9,0.9,0.2,1.1, SURF_ID6=,,'BEV_MT','BEV_MT','BEV_MT',/

&OBST ID='BURNER', XB=4.2,4.7,-0.3,0.3,0.0,0.0,SURF_IDS='FIRE',,/

&BNDF QUANTITY='ADIABATIC SURFACE TEMPERATURE'/

&TAIL/

I have set the fuel 'BEV' and I want to ignite the material 'BEV' with a propane burner, but only propane is burning throughout the entire process.

[drjfloyd]

&SURF ID='BEV_MT',
COLOR='GRAY 80',
SPEC_ID='BEV',
MATL_ID = 'DX_BEV',
IGNITION_TEMPERATURE=171,
THICKNESS=1/

Are any wall cells reaching 171 C?

&SPEC ID='BEV', FORMULA='C81.463H0.737N0.182F0.389Cl0.322'/

Is this correct or do you have a typo. As defined this is MW of ~1000 g/mol.

12.1.3 User Defined Gas and Liquid Properties
Enthalpy
....
If no input for specific specific heat is provided, then the specific heat of the gas will be calculated from
its molecular weight using the relation:
cp = γ/(γ −1) R/W

The ratio of specific heats, GAMMA, is 1.4 by default and can be changed on the MISC line. If you want all the
gas specific heats to follow this relation, set CONSTANT_SPECIFIC_HEAT_RATIO=T on the MISC line. For high molecular weight species, use of the default gamma will result in very low values of the specific heat which can cause issues with the default extinction model. In this case it is recommended that the specific heat be defined.

[yswwyx]

The defined new fuel only experiences mass loss during combustion, but does not have HRR output or flame. However, its loss rate meets the HRRPUA/HEAT-OF-COMBUSION that I have set

[drjfloyd]

&SURF ID='BEV_MT',
COLOR='GRAY 80',
SPEC_ID='BEV',
MATL_ID = 'DX_BEV',
IGNITION_TEMPERATURE=171,
THICKNESS=1/

You have defined IGNITION_TEMPERATURE=171. A wall cell will not start burning until it reaches 171 C. Do any of your wall cells on the bottom of the OBST reach 171 C in the input file that you attaced?

Add this line:

&DEVC XB=1.4,5.6,-0.9,0.9,0.19,0.21,IOR=-3,QUANTITY='WALL TEMPERATURE',SPATIAL_STATISTIC='MAX',TEMPORAL_STATISTIC='MAX'/

See what it says is the maximum temperature at any point in time on the bottom of the OBST.

Let's say some wall cell does reach 171 C. What inputs have you specified that defines how BEV burns? Where have you definde any inputs that FDS can use to compute the burning rate of the BEV MATL? Look at the examples in the User's Guide for using IGNITION_TEMPERATURE.

Then there is still the issue of your SPEC which I previously identified.