Oxygen Volume Fraction in a Staircase Fire

The goal of the FDS simulation presented in this page is to evaluate the oxygen volume fraction over time in a Staircase fire.

Download the FDS input file Download

1. Simulation summary

The specific simulation inputs that determine the oxygen volume fraction are the following:

Soot yield = 0,03 kg/kg
Carbon monoxide yield = 0,07 kg/kg
Heat Release rate = 120 kW

The following video shows the results of the simulation;

the graph shows the oxygen volume fraction over time on the different landings of the staircase;
the vector slice plots the air velocity with the arrow size and the oxygen volume fraction with the color map

Here is the video:

1.2. Input parameters

Reaction inputs:

&REAC ID = 'propane reaction', SOOT_YIELD=0.03, CO_YIELD=0.07, FUEL='PROPANE'/

Fire definition inputs:

&VENT XB= 0.3, 0.9, 1, 1.4, 0, 0, SURF_ID='FIRE'/ &SURF ID='FIRE', HRRPUA=500/

1.3. Outputs definition:

Devices:

&DEVC ID='ox1', XYZ=0.5,1.2,2, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox2', XYZ=3.6,1.2,3.53, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox3', XYZ=0.5,1.2,5.06, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox4', XYZ=3.6,1.2,6.59, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox5', XYZ=0.5,1.2,8.12, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox6', XYZ=3.6,1.2,9.65, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox7', XYZ=0.5,1.2,11.18, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/

Slice files:

&SLCF PBY = 1.2, QUANTITY='TEMPERATURE'/ &SLCF PBY = 1.2, QUANTITY='VELOCITY', VECTOR=.TRUE./ &SLCF PBY= 1.2, QUANTITY='VOLUME FRACTION', SPEC_ID= 'OXYGEN' / &SLCF PBY= 1.2, QUANTITY='VOLUME FRACTION', SPEC_ID= 'CARBON DIOXIDE' / &SLCF PBY= 1.2, QUANTITY='VOLUME FRACTION', SPEC_ID= 'CARBON MONOXIDE' /

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2. Complete input file

Download the FDS input file Download

&HEAD CHID='staircase_fire_ox_VF',TITLE='staircase_fire_ox_VF' &MESH ID='Mesh 01', IJK=28,16,144, XB=0,4.2,0,2.4,0,12.24/ &SURF ID= 'OBST', RGB=100,100,100, DEFAULT=.TRUE./ default obstructions color &TIME T_END=480, / &DUMP NFRAMES=7200./ &REAC ID = 'propane reaction', SOOT_YIELD=0.03, CO_YIELD=0.07, FUEL='PROPANE'/
####stairs geometry &OBST XB=0.9,1.2,0,1.2,0,0.17,RGB=200,200,200/ &OBST XB=1.2,1.5,0,1.2,0.17,0.34,RGB=200,200,200/ &OBST XB=1.5,1.8,0,1.2,0.34,0.51,RGB=200,200,200/ &OBST XB=1.8,2.1,0,1.2,0.51,0.68,RGB=200,200,200/ &OBST XB=2.1,2.4,0,1.2,0.68,0.85,RGB=200,200,200/ &OBST XB=2.4,2.7,0,1.2,0.85,1.02,RGB=200,200,200/ &OBST XB=2.7,3,0,1.2,1.02,1.19,RGB=200,200,200/ &OBST XB=3,3.3,0,1.2,1.19,1.36,RGB=200,200,200/ &OBST XB=3.3,4.2,0,2.4,1.36,1.53,RGB=200,200,200/ &OBST XB=0.9,1.2,1.2,2.4,2.72,2.89,RGB=200,200,200/ &OBST XB=1.2,1.5,1.2,2.4,2.55,2.72,RGB=200,200,200/ &OBST XB=1.5,1.8,1.2,2.4,2.38,2.55,RGB=200,200,200/ &OBST XB=1.8,2.1,1.2,2.4,2.21,2.38,RGB=200,200,200/ &OBST XB=2.1,2.4,1.2,2.4,2.04,2.21,RGB=200,200,200/ &OBST XB=2.4,2.7,1.2,2.4,1.87,2.04,RGB=200,200,200/ &OBST XB=2.7,3,1.2,2.4,1.7,1.87,RGB=200,200,200/ &OBST XB=3,3.3,1.2,2.4,1.53,1.7,RGB=200,200,200/ &OBST XB=0,0.9,0,2.4,2.89,3.06,RGB=200,200,200/ &OBST XB=0.9,1.2,0,1.2,3.06,3.23,RGB=200,200,200/ &OBST XB=1.2,1.5,0,1.2,3.23,3.4,RGB=200,200,200/ &OBST XB=1.5,1.8,0,1.2,3.4,3.57,RGB=200,200,200/ &OBST XB=1.8,2.1,0,1.2,3.57,3.74,RGB=200,200,200/ &OBST XB=2.1,2.4,0,1.2,3.74,3.91,RGB=200,200,200/ &OBST XB=2.4,2.7,0,1.2,3.91,4.08,RGB=200,200,200/ &OBST XB=2.7,3,0,1.2,4.08,4.25,RGB=200,200,200/ &OBST XB=3,3.3,0,1.2,4.25,4.42,RGB=200,200,200/ &OBST XB=3.3,4.2,0,2.4,4.42,4.59,RGB=200,200,200/ &OBST XB=0.9,1.2,1.2,2.4,5.78,5.95,RGB=200,200,200/ &OBST XB=1.2,1.5,1.2,2.4,5.61,5.78,RGB=200,200,200/ &OBST XB=1.5,1.8,1.2,2.4,5.44,5.61,RGB=200,200,200/ &OBST XB=1.8,2.1,1.2,2.4,5.27,5.44,RGB=200,200,200/ &OBST XB=2.1,2.4,1.2,2.4,5.1,5.27,RGB=200,200,200/ &OBST XB=2.4,2.7,1.2,2.4,4.93,5.1,RGB=200,200,200/ &OBST XB=2.7,3,1.2,2.4,4.76,4.93,RGB=200,200,200/ &OBST XB=3,3.3,1.2,2.4,4.59,4.76,RGB=200,200,200/ &OBST XB=0,0.9,0,2.4,5.95,6.12,RGB=200,200,200/ &OBST XB=0.9,1.2,0,1.2,6.12,6.29,RGB=200,200,200/ &OBST XB=1.2,1.5,0,1.2,6.29,6.46,RGB=200,200,200/ &OBST XB=1.5,1.8,0,1.2,6.46,6.63,RGB=200,200,200/ &OBST XB=1.8,2.1,0,1.2,6.63,6.8,RGB=200,200,200/ &OBST XB=2.1,2.4,0,1.2,6.8,6.97,RGB=200,200,200/ &OBST XB=2.4,2.7,0,1.2,6.97,7.14,RGB=200,200,200/ &OBST XB=2.7,3,0,1.2,7.14,7.31,RGB=200,200,200/ &OBST XB=3,3.3,0,1.2,7.31,7.48,RGB=200,200,200/ &OBST XB=3.3,4.2,0,2.4,7.48,7.65,RGB=200,200,200/ &OBST XB=0.9,1.2,1.2,2.4,8.84,9.01,RGB=200,200,200/ &OBST XB=1.2,1.5,1.2,2.4,8.67,8.84,RGB=200,200,200/ &OBST XB=1.5,1.8,1.2,2.4,8.5,8.67,RGB=200,200,200/ &OBST XB=1.8,2.1,1.2,2.4,8.33,8.5,RGB=200,200,200/ &OBST XB=2.1,2.4,1.2,2.4,8.16,8.33,RGB=200,200,200/ &OBST XB=2.4,2.7,1.2,2.4,7.99,8.16,RGB=200,200,200/ &OBST XB=2.7,3,1.2,2.4,7.82,7.99,RGB=200,200,200/ &OBST XB=3,3.3,1.2,2.4,7.65,7.82,RGB=200,200,200/ &OBST XB=0,0.9,0,2.4,9.01,9.18,RGB=200,200,200/
####mesh opening &VENT XB=1.8, 2.7, 0.9, 1.5, 12.24, 12.24, SURF_ID='OPEN'/
####fire design &VENT XB= 0.3, 0.9, 1, 1.4, 0, 0, SURF_ID='FIRE'/ &SURF ID='FIRE', HRRPUA=500/
####outputs #devc &DEVC ID='ox1', XYZ=0.5,1.2,2, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox2', XYZ=3.6,1.2,3.53, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox3', XYZ=0.5,1.2,5.06, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox4', XYZ=3.6,1.2,6.59, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox5', XYZ=0.5,1.2,8.12, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox6', XYZ=3.6,1.2,9.65, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ &DEVC ID='ox7', XYZ=0.5,1.2,11.18, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN'/ #slices &SLCF PBY = 1.2, QUANTITY='TEMPERATURE'/ &SLCF PBY = 1.2, QUANTITY='VELOCITY', VECTOR=.TRUE./ &SLCF PBY= 1.2, QUANTITY='VOLUME FRACTION', SPEC_ID= 'OXYGEN' / &SLCF PBY= 1.2, QUANTITY='VOLUME FRACTION', SPEC_ID= 'CARBON DIOXIDE' / &SLCF PBY= 1.2, QUANTITY='VOLUME FRACTION', SPEC_ID= 'CARBON MONOXIDE' /
&TAIL /