Comparison Between Actual and Simulated Smoke for Smoke Detection Certification in Aircraft Cargo Compartments Using the CFD Method

Simulated smoke has been widely used in place of actual fire smoke during flight tests in the certification process for aircraft cargo compartment smoke detection systems. Previous research has identified several differences between actual and simulated smoke. However, few studies have determined the quantitative effects of these differences on the transport and detection properties of actual and simulated smoke. The current work compared actual and simulated smoke using a computational fluid dynamics method with numerical models for the two types of smoke developed in the Fire Dynamics Simulator of the National Institute of Standards and Technology and validated through experimental data. The transport and detection properties of actual and simulated smoke were then evaluated quantitatively in detail. The two types of smoke were compared under two conditions: (1) at the same smoke-generating quantity and (2) at the same smoke release rate. Result showed that during the early stage of smoke occurrence, the numerical values of light transmission at different monitoring points in simulated smoke are 10% to 20% lower than those in actual fire smoke. Simulated smoke from the smoke generator is easier to detect than actual fire smoke. Therefore, the equivalence between simulated smoke and actual fire smoke should be focused on in the airworthiness verification of aircraft cargo smoke detection.