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Two-dimensional and quasi-3D in-flight ice accretion simulation codes have been widely used by the aerospace industry for the last two decades as an aid to the certification process. The present paper proposes an efficient numerical method for calculating ice shapes on simple or complex 3D geometries. The resulting ice simulation system, FENSAP-ICE, is built in a modular fashion to successively solve each flow, impingement and accretion via field models based on partial differential equations (PDEs). The FENSAP-ICE system results are compared to other numerical and experimental results on 2D and slightly complex 3D geometries. It is concluded that FENSAP-ICE gives results in agreement with other code calculation results, for the geometries available in the open literature.

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The interest on embedded boundary methods increases in Computational Fluid Dynamics (CFD) because they simplify then mesh generation problem in the case of the Navier-Stokes equations. The same simplifications occur for the simulation of multi-physics flows, the coupling of fluid-solid interactions in situation of large motions or deformations, to give a few examples. Nevertheless an accurate treatment of the wall boundary conditions remains an issue of the method. In this work, the wall boundary conditions are easily taken into account through a penalization technique, and the accuracy of the method is recovered using mesh adaptation, thanks to the potential of unstructured meshes. Several classical examples are used used to demonstrate that claim.

We propose to model ice shedding trajectories by an innovative paradigm that is based on cartesian grids, penalization and level sets. The use of cartesian grids bypasses the meshing issue, and penalization is an efficient alternative to explicitly impose boundary conditions so that the body-fitted meshes can be avoided, making multifluid/multiphysics flows easy to set up and simulate. Level sets describe the geometry in a nonparametric way so that geometrical and topological changes due to physics and in particular shed ice pieces are straight forward to follow. The model results are verified against the case of a free falling sphere. The capabilities of the proposed model are demonstrated on ice trajectories calculations for flow around iced cylinder and airfoil.

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A conjugate heat transfer procedure including droplet impingement and runback effects is presented and validated against experimental data in a mist-flow heat exchanger configuration and an engine nacelle geometry.Computations include the solution of the air flow field, the prediction of water droplets motion and the evaluation of the cooling effect of the water film on the solid surface. The entire analysis is carried out using FENSAP-ICE (Finite Element Navier-Stokes Analysis Package for Inflight icing), a simulation system developed by Newmerical Technologies for icing applications. The numerical model is described, including the Navier-Stokes solution, the water thin film computation, the droplet impingement prediction and the conjugate heat transfer procedure. The predictions are verified against experimental data for different droplet mass flow rates, showing satisfactory agreement and allowing a useful insight in the physical characteristics of the problem. NOMENCLATURECD Air-droplet drag coefficient C p Specific heat [kJ/kgK] D Tube diameter [m] d Droplet diameter [m] G Droplet mass flow rate [kg/m 2 h] h Heat transfer coefficient [kW/m 2 K] H Q Total enthalpy [kJ/kg] K Droplet inertia parameter k Thermal conductivity [kW/mK] L Reference length [m] raj Impinging mass flow [kg/s] t Associate Fellow. AIAA