The complete analysis of an in-flight icing problem typically begins with an airflow solution over a clean geometry and ends with a series of airflow solutions over a contaminated geometry to assess the performance degradation caused by ice build-up.

FENSAP solves the steady and unsteady compressible 3D Navier-Stokes equations. The fluid may be inviscid or viscous, in which case the flow may be laminar or turbulent, turbulence being modeled by one-equation or two-equation models. The heat fluxes at walls, of paramount importance for glaze icing, can be computed directly with second order accuracy by re-solving the energy equation on the solid surfaces.

Additionally, for propeller-driven aircraft, helicopter or tiltrotor geometries, a flow-through actuator disk can model the important propeller wake effects in a cost-effective manner. For more accurate predictions, unsteady rotor-fuselage interactions can be computed by considering fixed and rotating grid domains and by automatically stitching the two grids together after each rotor displacement.

OptiGrid is a comprehensive, automatic mesh adaptation and CAD reconstruction software which helps achieve the most accurate CFD simulations at the lowest computational cost. OptiGrid works in a fully-coupled manner with FENSAP and Fluent, or by using the generic file format introduced in this manual.

One of the most important features of OptiGrid lies in its innovative CAD reconstruction functionality, allowing mesh adaptation on grids generated by different mesh generators. A simple graphical interface allows you to regenerate the CAD automatically from the initial surface grid, and to define boundary conditions (such as symmetry and periodicity) before mesh adaptation.

OptiGrid assesses the mesh quality on each individual element edge, via a posteriori error estimator, given a solution on an initial mesh. Subsequently, OptiGrid systematically modifies the mesh in order to equalize the error to the given target throughout the solution domain. The grid is adapted by moving nodes, refining and coarsening edges, for example adding and removing grid points, and swapping edges. All operations are edge-based and therefore OptiGrid can be coupled with any finite volume or finite element flow code that uses unstructured meshes composed of any combination of hexahedral, tetrahedral, prismatic and pyramidal elements. The strength of OptiGrid lies in its ability to yield anisotropic (stretched) meshes which are able to capture high-resolution, three-dimensional features such as shocks, boundary layers, wakes, vortices and slip lines while fully respecting the reconstructed CAD.

Finally, OptiGrid can be used as a mesh smoothing tool before any calculations to set the desired number of grid points provided by you and align cells with the curvature of the surfaces.

DROP3D is the 3D Eulerian (one-shot) water droplet/ice crystal impingement module of the FENSAP-ICE system. DROP3D works seamlessly in conjunction with FENSAP, Fluent and CFX or accepts flow solutions from other CFD codes of equivalent capabilities. It handles impingement for both external and internal flows.

DROP3D solves fine-grain partial differential equations for particle velocity and water concentration. DROP3D therefore provides, in a single shot, water concentration, droplet velocity vectors, water catch efficiency distributions, impingement patterns, shadow zone characteristics and impingement limits over the entire domain without the laborious iterative procedure of seeding droplets at injection points.

DROP3D can also be used for a wide variety of other demanding situations where particles are suspended in a carrier fluid, such as screens, pollutant dispersal, collection and condensation rates on HVAC components, etc.

ICE3D is the 3D ice accretion module of the FENSAP-ICE system, also based on fine-grain partial differential equations for the complex thermodynamics of ice formation. It yields 3D ice shape, water film thickness and surface temperature on any number of complex 3D surfaces.

ICE3D can output the displaced 3D grid after ice accretion. Performance degradation due to ice accretion can be easily computed by simply restarting FENSAP on this new grid. The 3D ice shape is also saved in .stl and TETIN CAD formats to allow manual grid re-generation after each ice accretion period.

CHT3D is the 3D Conjugate Heat Transfer (CHT) module of the FENSAP-ICE system that couples airflow convection (from FENSAP) and heat conduction through solids (from C3D) for dry-air heat transfer calculations and, in conjunction with DROP3D (droplets impact) and ICE3D (ice accretion), for wet-air anti-icing calculations. CHT3D can also be operated in steady or unsteady de-icing modes, and also provides three different levels of fidelity, depending on the application and the tradeoff between execution time and the required accuracy.

CHT3D is applicable to a wide variety of other demanding fluid-solid interface heat transfer situations, such as piccolo tubes embedded in wing leading edges, engine nacelle leading edge heating, electro-thermal heating, gas turbine blade cooling, heat dissipation in car or airplane brakes, automotive engine cooling and casting processes.