Mass Loss rate

[PurnaPushkalaSomasundaram]

Hello! This Is Purna Pushkala from Politecnico di Milano. I am using FDS for my thesis work. I have made a model of a corn oil tank of 0.8m in diameter and 0.25 m in height and have given inputs for the pool fire studies. The mass loss rate is obtained from the experimental studies as 0.039028 kg/(m²·s). It is found that the mass loss is double times what the actual mass loss is supposed to be. I don't know if this is right or wrong. I need help with this issue.

[mcgratta]

What assumptions have you made in your model? Soot yield? Absorption coefficient? Liquid properties? Chemical composition of the evaporated vapors?

[PurnaPushkalaSomasundaram]

I can give you the input. Soot yield= 0.038
CO Yield=0.02
HCN yield = 0.01
heat of combustion=40630 kJ/kg
Mass loss rate=0.039028 kg/m2s
Corn oil = C22H25O2N

[drjfloyd]

We have no idea what your inputs are, how are we supposed to help you? Make sure you have read the FDS documentation and looked at any relevant example files. If that does not help, attach a simple input file that demonstrates the problem.

[drjfloyd]

This is not the FDS input file.

[PurnaPushkalaSomasundaram]

Sorry, I think the file is not the correct one. I will send you the correct one.
2.odt

[PurnaPushkalaSomasundaram]

sorry it was in an FDS text file and couldn't upload it so sent in Word doc. with the coding in it

[rmcdermo]

@PurnaPushkalaSomasundaram Rename the FDS input file (casename.fds) to (casename.txt) and then it will upload to GitHub.

[PurnaPushkalaSomasundaram]

PurnaPushkalaSomasundaram..txt

[mcgratta]

GEOMETRY='CYLINDRICAL',
 LENGTH=0.25,
 RADIUS=0.4/

These parameters are not appropriate for your case. The liquid surface is not a cylinder.

[rmcdermo]

I don't see where it is exceeding this value. It is following your ramp.

Please take a step back and start simple. Create one OBST with the top area of 1 m2. Apply HRRPUA without a ramp. Convince yourself that you see the correct mass loss rate (see MLR from _hrr.csv).

Then... add back your ramp. Check.

Then... create a circular geometry. Check.

[PurnaPushkalaSomasundaram]

okay thank you so much and I will try this and let you know.

[drjfloyd]

MRLPUA uses RAMP_Q.

[PurnaPushkalaSomasundaram]

okay, so the graph that I have posted in the first question is correct?

[PurnaPushkalaSomasundaram]

Hello! I tried a sample as you said. I can show you the FDS file with the MLR graph.
model_git.txt