Numerical simulation on the influence of low air pressure upon smoke spread and fire alarm process

The airplane cargo fire is a severity disaster for the airplane in flight. The fire alarm system in cargo compartment plays an important part of the flight safety, which is a useful method to reduce the severity fight fire. However, the inflight altitude of airplane has been leading a low air pressure condition in the cargo, which should be affect the smoke spread and fire alarm process in the air cargo. In this paper, the smoke spread and fire alarm process has been investigated via numerical simulation. The various air pressure, fire source with different heat release rate and soot yield rate have been also discussed. During the simulation process, we can obtain the smoke spread, temperature distribution, and obscuration rate under the designed fire conditions. The fire alarms system response time of point-type smoke detector and line-type smoke detector (LSD) system have discussed under different fire scenarios and mounted location. The results indicate that the lower air pressure would accelerate the smoke speed velocity and bring the fire alarm time forward. The anti-interference property of LSD should be enhanced as the low air pressure influence and severe environment in the aircraft cargo. The results should offer the technical and scientific support for the cargo fire alarm system