Use of FDS for Jet fires

[Kelly]

Hi!
By experience with FDS has been in an academic setting and now my
company is looking to utilize FDS as a tool to provide clients with a
more detailed analysis. We provide service to the oil and gas sector
and the problems we encounter are jet fires and pool fires. I have
received clarification that FDS is not the tool to use for high
pressure, supersonic jet fires. However, would it be suitable for a
lower velocity/pressure jet fire? Or is FDS just not the tool to
analyze jet fires?

If FDS is able to analyze lower velocity/pressure jet fires, I am
hoping to compare some test data we have for the flame length of a
methane gas jet fire with what FDS can do. Will it be possible to
program a pressurized release of a gas in FDS?

I appreciate any advice you can provide. Thanks!
-Kelly

[Kevin]

FDS is a low Mach number model, so avoid exit speeds that approach the
speed of sound. Most often, we just use a larger orifice and lower
velocity. Also, in default mode, FDS does not account for high strain
extinction, like blow-off. Finite-rate chemistry is possible, but
often difficult when the resolution of the grid is not adequate.

Best advice is to try something simple and work your way up. The issue
is not necessarily whether FDS can "do" a particular calculation, but
rather how well. You can certainly shoot methane out of a hole and
make it burn, but whether this is a good model of the real thing
depends on a number of parameters. Jason Floyd did some work on
hydrogen jets with FDS for the NFPA Research Foundation. You might
want to see if that report is available.