Computational Method for Ice Crystal Trajectories in a Turbofan Compressor 2015-01-2139
In this study the characteristics of ice crystals on their trajectory in a single stage of a turbofan engine compressor are determined. The particle trajectories are calculated with a Lagrangian method employing a classical fourth-order Runge-Kutta time integration scheme. The air flow field is provided as input and is a steady flow field solution governed by the Euler equations. The single compressor stage is represented using a cascaded grid. The grid consists of three parts of which the first and the last part are stator parts and the centre part is a rotor.
Each particle is modelled as a non-rotating rigid sphere. The remaining model does allow the exchange of heat and mass to and from the particle resulting in a mass, temperature and phase change of the particle. The phase change is based on a perfectly concentric ice core-water film model and it is assumed that the particle is at uniform temperature.
The results for the collection efficiency, particle temperature and amount of evaporated mass will be shown for two extreme scenario's. The first simulation is carried out at standard conditions for a Boeing-747 at cruising conditions using the International Standard Atmosphere (ISA) at that altitude, i.e. at 10,650 m. The second simulation is carried out at lower altitude where the existence of supercooled liquid water is thought to be unlikely. Both simulations are carried out at two different temperatures and for either dry or saturated air. The range of particle diameters is set from 10 to 500 micrometres.