Effect of Super - Cooled Water Droplet Characteristics on Fan Rotor - Ice Accretion

This paper presents a methodology for numerical simulations of super-cooled three-dimensional (3-D) water droplet trajectories through aeroengine rotating machinery that includes the effect of energy exchange between the droplets and flow. The governing equations for both flow and droplets are formulated and solved within the reference frame of rotating blades. A Eulerian-Lagrangian approach is used for the continuous and discrete phases with oneway interaction models to simulate the momentum and energy exchange between the two phases. The methodology is applied to a transonic fan rotor and results are presented for the computed flow field and droplet trajectories in the rotor reference frame. Results are also presented for the computed water collection efficiency and impingement temperature distribution over the fan blade surface for different droplet sizes and initial temperatures. The droplet size affects their trajectories and collection efficiency. The results demonstrate the significant effect of energy exchange on the rotating blade impingement temperatures for the smaller droplets. While the amount of ice accretion on the fan blade is determined by the collection efficiency; its type, whether glaze or rime ice is determined by the impingement temperature.