Civil aircraft emergency Ram air ventilation system performacne analysis and test

An emergency ram air ventilation system performance simulation model is developed based on Flowmaster platform, and a coupling CFD model of internal and external flow field of civil aircraft ram air inlet is established to get ram air total pressure performance. The results show that both of flight speed and altitude affect emergency ventilation performance; the faster speed is, the more flesh air flow; the higher altitude is, the lower flesh air flow; working condition of recirculation system will also affect the emergency ventilation flow through ventilation flow resistance, flesh air flow significantly reduced if recirculation system on. A flight test of emergency ventilation performance is carried out on a civil aircraft and analysis result is in good agreement with test results, which shows that system simulation analysis methods are reasonable and feasible. It also provides data support for the performance design and airworthiness certification of emergency ventilation system