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This study provides a comparison between an Eulerian and a Lagrangian approach for simulation of ice crystal trajectories and impact in a generic turbofan compressor. The engine-like geometry consists of a one-and-a-half stage (stator-rotor-stator) compressor in which the computed air flow is steady and inviscid. Both methods apply the same models to evaluate ice crystal dynamics, mass and heat transfer, and phase change along ice crystal trajectories. The impingement of the crystals on the blade surfaces is modeled assuming full deposition for comparison and validation purposes. Moreover, the effect of ice crystal diameter and sphericity variations on impinging mass flux and a

In this study a comparison is made between results from three Eulerian-based computational methods that predict the ice crystal trajectories and impingement on a NACA-0012 airfoil. The computational methods are being developed within CIRA (Imp2D/3D), ONERA (CEDRE/Spiree) and University of Twente (MooseMBIce). Eulerian models describing ice crystal transport are complex because physical phenomena, like drag force, heat transfer and phase change, depend on the particle's sphericity. Few correlations exist for the drag of non-spherical particles and heat transfer of these particles. The effect or non-spherical particles on the

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Compared to conventional icing additional droplet phenomena have to be accounted for in icing caused by supercooled large droplets (SLD) such as splashing, rebound, breakup and deformation. In this study the effect of the presence of a thin liquid film of water on the surface has been investigated. This liquid layer can arise when SLD droplets freeze only partially following impact on the airfoil. The effect of the liquid film is simulated by using the wall shear stress and by assuming a linear velocity profile in the liquid layer. The shear stress is calculated by coupling an integral boundary-layer method to a potential flow method. An improved splashing model has been implemented in the existing computational method. This splashing model consists of a deposition model that accounts for splashing during impact of droplets on a liquid layer. In an extension to this model different solidification models have been investigated to estimate the time of solidification of a liquid splat produced on the surface after impact. One is a planar solidification model which is described by the Stefan problem for heat conduction and which is mostly controlled by diffusion. The second model is based on dendritic solidification, which is rapid and governed by kinetics. The results of the deposition model on SLD ice accretion are compared with data from experiments on a NACA-23012 airfoil and on a NACA-0012 airfoil. Good agreement is found. Nomenclaturec Chord, m C p Specific heat d Diameter, m f D Drag force per unit mass, N/kg g Gravitational acceleration, m/s 2 h Height, m K Cossali splashing parameter k Thermal conductivity, W/mK L Latent heat, J/kġ m in Inflowing mass flow rate per meter span, kg/m 3 s n Unit normal vector N h Number of droplets hitting the splaṫ q w Volumetric flux of impacting droplets, m 3 /m 2 s T Temperature, K t Time, s t solid Solidification time, s u Velocity, m/s * PhD student, faculty of Engineering Technology, group Engineering Fluid Dynamics † PhD student, faculty of Engineering Technology, group Engineering Fluid Dynamics, presently Zeton B.V.,

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