COMETAD


This project is devoted to development of computational and experimental techniques for the
analysis and design of polymersin fire situations. It is well-known that thermoplastic-made
domestic objects (such as, e.g. mattresses) tend to melt creating secondary ignition pools. Such
polymeric objects can be treated as viscous fluids with high time-dependant viscosity.  In this
project we presented a computational algorithm for modeling thermoplastic polymer melting
under fire conditions. We proposed a technique that aims at minimizing the computational cost,
while providing realistic results regarding liquified polymer propagation. This is achieved by
using the embedded-like approach, combining the particle finite element method for the polymer
with an Eulerian formulation for the ambience (hot air). The polymer and ambience domains
interact over the interface boundary. The boundary is explicitly defined by the position of the
Lagrangian domain (polymer) within the background Eulerian mesh (ambience). This allows to
solve the energy equation for both subdomains on the Eulerian mesh with different thermal
properties. Radiative transport equation is exclusively considered for the ambience, and the heat
exchange at the interface is modeled by calculating the radiant heat flux and imposing it as a
natural boundary condition.

Ul94 test

Numerical simulation vs experiment:

Embedded Lagrangian-Eulerian model used in COMETAD: moving (Lagrangian) mesh: polymer, fixed (Eulerian) mesh: surrounding air