Aluminium composite panels

[FDS EVAC]

Hi FDS users,

As a part of my project work, I need to simulate the burning of  aluminium composite panels (ACP) in a fire environment. I have done the priliminary studies related to this and realised that burning of ACP in fire environment is difficult. In addition to this, i performed the simulations keeping the ACP infront of constant high temperature source. From the results, i could see that heat transfer through the ACP using thermocouples.

But i could not burn the polyurethane which is sandwiched by aluminium panels in fire environment.

If anybody successfully burned the polyurethane sandwiched by aluminium panels in the fire environment, please guide me how to achieve it. I badly need help in  this regard.

Thank you in advance for your help.

[fde]

Are you interested in a real fire experiment or simulation in FDS? Because to have a combustion in FDS you need fuel in gas phase. Aluminium layer might be blocking the behind layers to pyrolisis into environment. 

To simulate the burning, you need to replicate real life fail mechanism of the ACP. Those panels are often rated as A2 and almost non-combustible because the test is done by applying heat to the aluminium face. However if there is any gap and flame enter sideways where the inner combustible material is directly exposed to flames then the combustion is much easier to take place. You might look into fail scenarios or real tests to mimic the same. 

Furthermore if you apply enough heat the aluminium will melt around 660 C and create an opening to the inner core. 

[FDS EVAC]

Hi fde,

Thank you for your email.

I want to model the burning of ACP in FDS. I am asking help to model the fail mechanism so that polyurethane  can be burnt. 

Thank you

--
You received this message because you are subscribed to the Google Groups "FDS and Smokeview Discussions" group.
To unsubscribe from this group and stop receiving emails from it, send an email to fds-smv+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/fds-smv/a5d60759-44e6-4308-83af-e6585c68230bn%40googlegroups.com.

[FDS EVAC]

In addition to my earlier email, i have gone through the literature aswell, to know how model the melting of aluminium and then burning of polyurethane. But i have not come across such an article. 

Can anybody throw some light on the modeling part.

Thank you

[FDS EVAC]

ANY SUGGESTIONS?

[fde]

Maybe you can investigate of modelling a burner based on the temperature. If you measure the temperature at a depth of the aluminium layer thickness, you can activate the burner when the aluminium layer is assumed to be melted. However I think grid size might have a big impact on this since temperature might deviate as the cell size is reduced due to volume averaging. In reality the flame sheet has a high temperature but in CFD this few mm thick flame sheet will be captured by a cell which is in a few order larger size. It will be averaged and temperature would be measured lower. Ultimately this would result the failure of the ACP to be delayed. 

My point is this is not a common application such as finding average upper layer temperature therefore it should be approached carefully. 

[Jonathan Hodges]

What phenomena are you trying to capture in your model? It's a different problem if you are trying to come up with a pyrolysis model to describe the burning of that material or trying to model enclosure fire dynamics resulting from this material. Could you provide a bit more detail on the specific application you are trying to model?

One of my colleagues' dissertations focused on modeling burnthrough of aluminum (https://vtechworks.lib.vt.edu/handle/10919/64154). He was generally looking at thicker samples than what you are describing, but it may be a good starting point on the aluminum side.

[dr_jfloyd]

This is a very challenging application to model in FDS; I would consider this a research application rather than routine use of FDS. 

The panels can melt and directly expose the PU core; however, there are other ways to get PU burning. The panels can delaminte. This is going to depend on panel construction, how the panels are mounted, and the details of the adhesive used to bond the alunimum to foam. This is likely going to need data from actual tests to understand. If the panel edges are open, then as heat is trasnferred through the aluminum into the PU core it will being to pyrolyze and the vapors could migrate to edges and be exposed to the fire and ignite. The melting part is the easiest, just prescribe a reaction on the MATL line for the aluminum to melt it. The others aren't something that there are a simple set of FDS inputs for. You will need to develop and validate a methodology for those.

On Wednesday, May 24, 2023 at 5:15:53 AM UTC-4 fde wrote: