Fire Suppressant Transport Modeling

ABSTRACT: Fires initiating in engine nacelles and dry bays are the most common causes of loss of aircraft. However, since the Montreal Protocol restricting the production of Halons, a replacement has not yet been accepted by the aircraft survivability community despite numerous testing programs. The costs and limitations of designing new systems based primarily on live fire testing can be mitigated by modeling. In this Phase II project, ADA Technologies is partnering with Fire Science NM and SURVICE Engineering to develop, validate and implement a fast-running, physics-based, computational fluid dynamics (CFD) code for mapping the concentration of clean agent fire suppressants in obstructed environments such as dry bays. At the core of the simplified approach is the focus on the low-Mach number equations, describing phenomenon happening in the subsonic regime, such as the dispersion of fire suppressant. The Phase I preliminary model demonstrated the required speed and accuracy. In Phase II, the code will be further streamlined and thoroughly validated against full-scale test data. Finally, the code will be converted to a module and integrated into the FPM (Fire Prediction Model) platform for use by the DoD survivability community. BENEFIT: A fast-running CFD code modeling the dispersion of Halon replacements, also known as clean agents, would allow optimization of new fire suppression designs by minimizing the amount of suppressant to be carried on-board an aircraft while ensuring satisfactory extinguishment performance. Limiting weight is always a primary concern in aircraft applications. Finding an effective and environmentally friendly replacement for Halon 1301 for dry bay and engine nacelles would be greatly aided by such a validated CFD code. This code would be applicable to a variety of fire suppression applications looking for optimized Halon replacement systems. DOD markets include a variety of new and retrofit applications linked under the joint aircraft survivability program. Beyond military aircraft, commercial aircraft is another natural fit for the code, as airframers are facing the same issue for engine nacelle and APU protection. Finally, weight and cost optimization of fire suppression systems of other, non-aerospace obstructed volumes is another commercialization opportunity. For examples, light armored vehicles in the DOD market and server rooms in the commercial sector represent promising business prospects for the future code.