The effects of equivalence ratio, fuel droplet size, and radiation on jet spray flame are investigated by means of two-dimensional direct numerical simulation (DNS). In addition, the validity of an extended flamelet/progress-variable approach (EFPV), in which heat transfer between droplets and ambient fluid including radiation is exactly taken into account, is examined. n-decane (C10H22) is used as liquid spray fuel, and the evaporating droplets' motions are tracked by the Lagrangian method. The radiative heat transfer is calculated using the discrete ordinate method with S-8 quadrature approximation. The results show that the behavior of jet spray flame is strongly affected by equivalence ratio and fuel droplet size. The general behavior of the jet spray flames including the heat transfer between droplets and ambient fluid with radiation effect can be captured by EFPV. (C) 2012 Elsevier Ltd. All rights reserved.

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. (C) 2012 Elsevier Ltd. All rights reserved.