Two-dimensional direct numerical simulation of spray flames – Part 2: Effects of ambient pressure and lift, and validity of flamelet model

The effect of ambient pressure on spray flames is investigated by means of two-dimensional direct numerical simulation (DNS), and the validity of an extended flamelet/progress-variable approach (EFPV) is examined under the high-pressure condition. The DNS is performed not only for a simple jet spray flame with a pilot burner but also for a lifted recirculation spray flame without any pilot burner at ambient pressures of 0.1 and 0.5 MPa. n-decane (C10H22) is used as liquid spray fuel, and the evaporating droplets’ motions are tracked by the Lagrangian method. The results show that the behaviors of jet and lifted recirculation spray flames are strongly affected by ambient pressure. The effects of the change of the ambient pressure on these spray flame behaviors can be well captured by EFPV and EFPV coupled with G-equation model (EFPV-G), respectively.