Issue With Fire Extinguishing On Its Own #16124
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Asher19000349
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Have you tried it with the latest FDS version? |
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I am developing a hydrogen fire scenario using the PyroSim version 2022.3.1208 running on FDS 6.5.3. To develop the model, I am following the exact source information, and mesh configuration from this paper: https://doi.org/10.1016/j.ijhydene.2021.01.130
The model replicated at my end matches the HRR, and flame characteristics appropriately. However, apparently, the combustion extinguishes after around 15-17 secs of simulation time. I tried the following workarounds:
(1) Using HRRPUA instead of MLRPUA. This does not change the physics, but I hoped if it could lead to better numerical stability.
(2) Using all OPEN boundaries, as well as, INERT/closed for all boundaries, and in one case all closed with ZMAX open, to reduce the excessive air entrainment and prevent flame blow-off.
(3) I also ran the software using latest FDS and PyroSim, but the results became disturbed, and the version I used was given correct results jut that the fire extinguishes.
I am pasting below the FDS code. and the smokeview video showing the fire extinguishing.
FDS CODE
&HEAD CHID='validation6'/
&TIME T_END=70.0/
&DUMP DT_RESTART=300.0, DT_SL3D=0.25/
&MISC SIMULATION_MODE='LES'/
&MESH ID='Mesh01', IJK=50,50,70, XB=4.0,9.0,2.55,7.55,6.0,13.0/
&REAC ID='Reaction1',
FUEL='HYDROGEN',
HEAT_OF_COMBUSTION=1.42E+5/
&DEVC ID='T1', QUANTITY='TEMPERATURE', XYZ=7.0,4.45,6.85/
&DEVC ID='T2', QUANTITY='TEMPERATURE', XYZ=6.8,4.45,6.85/
&DEVC ID='T3', QUANTITY='TEMPERATURE', XYZ=6.6,4.45,6.85/
&DEVC ID='T4', QUANTITY='TEMPERATURE', XYZ=6.4,4.45,6.85/
&DEVC ID='T5', QUANTITY='TEMPERATURE', XYZ=6.2,4.45,6.85/
&DEVC ID='T6', QUANTITY='TEMPERATURE', XYZ=6.0,4.45,6.85/
&SURF ID='Surface01',
FYI='Jet fire',
COLOR='RED',
MLRPUA=0.5,
ADIABATIC=.TRUE./
&OBST ID='jet release', XB=7.2,9.0,4.4,4.5,6.2,6.9/
&VENT ID='Mesh Vent: Mesh01 [XMAX]', SURF_ID='OPEN', XB=9.0,9.0,2.55,7.55,6.0,13.0/
&VENT ID='Mesh Vent: Mesh01 [XMIN]', SURF_ID='OPEN', XB=4.0,4.0,2.55,7.55,6.0,13.0/
&VENT ID='Mesh Vent: Mesh01 [YMAX]', SURF_ID='OPEN', XB=4.0,9.0,7.55,7.55,6.0,13.0/
&VENT ID='Mesh Vent: Mesh01 [YMIN]', SURF_ID='OPEN', XB=4.0,9.0,2.55,2.55,6.0,13.0/
&VENT ID='Mesh Vent: Mesh01 [ZMAX]', SURF_ID='OPEN', XB=4.0,9.0,2.55,7.55,13.0,13.0/
&VENT ID='Mesh Vent: Mesh01 [ZMIN]', SURF_ID='OPEN', XB=4.0,9.0,2.55,7.55,6.0,6.0/
&VENT ID='Vent', SURF_ID='Surface01', XB=7.2,7.2,4.4,4.5,6.8,6.9/
&SLCF QUANTITY='TEMPERATURE', VECTOR=.TRUE., CELL_CENTERED=.TRUE., ID='temp', PBY=4.4/
&SLCF QUANTITY='TEMPERATURE', VECTOR=.TRUE., CELL_CENTERED=.TRUE., ID='temp 2', PBY=4.45/
&SLCF QUANTITY='VELOCITY', VECTOR=.TRUE., CELL_CENTERED=.TRUE., ID='Vel', PBY=4.4/
&SLCF QUANTITY='VELOCITY', VECTOR=.TRUE., CELL_CENTERED=.TRUE., ID='Vel2', PBY=4.45/
&TAIL /
VIDEO
fire.extinguishing.mp4
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