Recent studies forecast a sustained annual growth of passenger air traffic by nearly 5% over the next 20 years. It is inevitable that airlines and airframers will have to focus on improved cabin ventilation as a major contribution to increased passenger comfort, in order to secure and hold a share of that market. In addition to that there is a constant demand on improving working conditions for pilots and cabin crews. This includes, among others, a reliable ventilation system, ensuring a certain level of comfort in areas such as the flight deck, crew rest areas, galleys, etc.

With constantly rising air traffic there is a risk of spreading of airborne transmitted diseases. Concern over the spread of Severe Acute Respiratory Syndrome (SARS) during 2003, ensured that aircraft cabin ventilation systems became the focus of some public interest. Aerospace companies are constantly under pressure to ensure a safe and clean environment in the cabin.

As product development times are being reduced, the need for virtual product development (VPD) arises, as it does in other industries. CFD methods, initially employed for external flow problems have now found their way into the design cycle of aircraft ventilation systems and are rapidly growing in their importance.

ICON has employed state of the art CFD methods for aircraft ventilation systems for a variety of airplane types and systems. Mixing and recirculation systems were investigated as well as cabin air flow patterns. CFD is able to help improve passenger comfort in aircraft cabins by predicting a number of important parameter such as:

• Velocity field / maximum velocity at passenger
• Temperature field / temperature gradient around passenger
• Humidity
• Age of Air / Air change effectiveness
• Predicted Mean Vote (PMV) / Predicted Percentage of Dissatisfied (PPD)
• Pollutant spread / removal

Furthermore, aircraft cargo holds have been investigated with respect to:

• Flow field / Air change effectiveness
• Fire and smoke detection
• Pollutant spread / removal

Modern optimisation methods are increasingly employed to improve performance of mixing and recirculation systems as well as the design of air distribution devices and will soon be an integral component for cabin ventilation prediction.