Settings of Sodium fire in FDS

[lihy213]

Dear developers,

I want to set up a combustion reaction of liquid metal sodium in FDS, where the temperature of the sodium is about 500°C and the pressure is 2 atm., and the reaction is the combustion of the sodium in contact with oxygen. But setting up the fuel as sodium directly in REAC line prompts a simple chemical reaction containing only C, H, O, etc. I tried setting up the reactants, oxidizers, and products separately in the SPEC line in lumped species. I'm not sure if this is the right way to do it. Can you please answer how I should set this up correctly?
My case is setted as follow,
sodium_fire_pan.txt

Regards

LI

[drjfloyd]

User's Guide 13.2

[lihy213]

Now I am stuck in this situation.

[drjfloyd]

Your input lines do not contain all the mechanism via which sodium oxidizes. You have no MATL reaction for direct oxidation on the liquid surface. I cannot tell you what those inputs should be, I do not know the kinetics of sodium oxidation. That is something you will need to research and determine.

[lihy213]

Now the question is that the liquid sodium is evaporated into gas but not burn up. If I set the specified MASS_FLUX, it fires, despite it doesn't satisfy the real process.

[lihy213]

Another question: I specify the TMP_FRONT or TMP_INNER in the SURF line and monitor the WALL TEMPERATURE through a DEVC with a SURF_ID of the specified SURF, the wall temperature begins with TMPA rather the TMP_FRONT or TMP_INNER.

[drjfloyd]

This is what the User's Guide says those inputs do. Deciding which one is appropriate for your specific needs is a decision for you to make based on how you ultimately decide to model the sodium fire.

8.2.1 Specified Solid Surface Temperature

the input TMP_FRONT, the surface temperature in units of ◦C, can be used to specify a fixed
temperature boundary condition

8.3.4 Initial Solid Temperature

By default, the initial temperature of the solid material is set to ambient (TMPA on the MISC line). Use
TMP_INNER on the SURF line to specify a different initial temperature of the solid.