FENSAP-ICE Modeling of the Ice Particle Threat to Engines in Flight 2007-01-3323
A series of turbofan engine malfunctions characterized by flameout and rollbacks at high altitudes have been reported and analyzed by flight safety agencies and concerned industries1. Conclusions pointed the source of these incidents to be an ice accretion build-up in the low-pressure compressor of the turbofan explained by the presence of ice crystals in the flying environment. In order to provide a numerical tool to analyze such situations, a new capability is developed within FENSAP-ICE2 that provides an unsteady model for ice crystals accretion in jet engines. The first step of this study is concentrated on adapting FENSAP-ICE to turbomachinery problems. A 3D unsteady parallel approach for rotor-stator interaction is developed, allowing the treatment of multi-stage blade motion in mixed relative and absolute frames of reference via a finite element interpolation method at interfaces3. The approach is demonstrated using the NASA compressor stage 35. As a first approximation, physical correlations of ice crystals are substituted in the droplet module of FENSAP-ICE, DROP3D, to obtain the unsteady ice crystals impingement zones in a turbomachinery stage, using flux-based collection efficiency. Particular attention is paid to the effects of unsteady rotor-stator interaction across the crystals’ trajectories.