Use of rollback for fire simulation

[Florian Michelin]

The scenario of the simulation is a fire in the fuel bay. The fuel bay is located in a roadway between fresh and exhaust air. An orifice allows 12 m3/s to go through that roadway.

First the fire simulation was run normally (without rollback). The contaminated air goes through to the exhaust and the fresh air stays fresh. It seems like everything would be “ok” if a fire broke out in this location. Fire response team will be able to reach the fire from the fresh air system without trouble.

 Figure 1: After simulation with no rollback

The rollback was then set up around the junction before the fire, it seemed the most likely place for rollback to occur. To place rollback, select the airway where rollback could happen and under the draw menu click “Construct rollback”.

Figure 2 : Rollback at the junction before the fire.

 

The simulation showed that after 10 min rollback starts happening and soon become constant. The result was high level of CO in the fresh air system.

Figure 3 :  simulation after rollback

This simulation highlight the importance of using the rollback feature when fires are happening close to a junction where smoke could potentially reverse and contaminate the fresh air system.