Development of a smoke transport model to enhance the certification process for cargo bay smoke detection systems

Current regulations require that aircraft cargo compartment smoke detectors alarm within one minute of the start of a fire and at a time before the fire has substantially decreased the structural integrity of the airplane. Presently in-flight and ground tests, which can be costly and time consuming, are required to demonstrate compliance with the regulations. A physics based Computational Fluid Dynamics (CFD) tool, which couples heat, mass and momentum transfer, has been developed to decrease the time and cost of the certification process by reducing the total number of both in-flight and ground experiments. The tool would provide information on smoke transport in cargo compartments under various conditions, therefore allowing optimal experiments to be designed. The CFD based smoke transport model will enhance the certification process by determining worst case locations for fires, optimum placement of fire detector sensors within the cargo compartment, and sensor alarm levels needed to achieve detection within the required certification time. The model is fast-running to allow for simulation of numerous fire scenarios in a short period of time. In addition, the model will be user friendly since it will potentially be used by airframers and airlines not expected to be experts in CFD. Following verfication of this CFD code, full-scale experiments will aid in the validation of the code and will gauge the reliability of using such a formulation to increase the efficiency of the aircraft fire detection system certification process by decreasing the total number of ground and flight experiments. This document includes a description of the CFD model and simulation studies developed to test the modeling strategy and numerical implementation of the CFD algorithm. Copyright © International Association for Fire Safety Science