3D Ice Prediction tool - ICECREMO2

The safety and effectiveness of a wide variety of aerospace products during operation within icing conditions must be demonstrated by manufacturers.

The products include Civil / Military airframes, helicopters, UAVs, engines, sensors and instrumentation. Traditional 2D ice accretion models, while providing an extremely valuable modelling tool, cannot by their very nature examine more complex structures and designs. ICECREMO2 is being developed through an effective partnership of BAE Systems, Airbus UK, Rolls-Royce, Dunlop Aerospace, Westland Helicopters, QinetiQ and Cranfield University with funding support from the DTI CARAD programme. The 3-year project builds on the technology developed under the ICECREMO1 programme significantly extending useability, robustness and capability.

ICECREMO2 provides a capability to predict ice accretions on complex 3-dimensional shapes over a wide range of environmental conditions. The generic, unstructured nature of the code allows interfacing with any CFD code including commercial software such as FLUENT. This enables the code to be utilised by a wide user base regardless of the type of embedded CFD processes in that organisation. Prediction capability is being extended by including anti-icing and ice-shedding models. It allows functionality of a wide range of airframe components in icing conditions to be defined and extends support for the specification, design and testing of ice protection equipment.

The ICECREMO code utilizes a novel 3D water film / freezing model which operates on an unstructured surface mesh with a discretisation of quads and/or triangles. Droplet trajectories are calculated through a given unstructured CFD flow solution and rate and location of water impingement is determined. Novel algorithms for determining, and refining, droplet start locations are employed and the code can include the effect of droplet splash and droplet size spectra. The unsteady development of the water flow and the rate, type and location of ice is then simulated.The structure/ice/water layers are discretisated to model the effects of anti-icing systems. A semi-empirical database is being incorporated into the software to allow estimation of ice-shedding events.

Results are output in a variety of formats for visualisation including commercially available packages - TECPLOT and FIELDVIEW. Surface data can be cut in an arbitrary manner to allow 2D slice information to be extracted. The ICECREMO code IPR is held within the partnership and access is free to each of the partners. Joint agreement is required for code access outside the partnership. Extensive validation studies are planned by the partners using comparisons to existing experimental and predicted data. Additional experimental data is also being generated via an icing tunnel campaign aimed primarily at anti-ice methodology validation.

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