Simulation and prevention of ice formation and shedding on rotorcraft
Politecnico di Milano (Italy)
University of Glasgow (UK)
Strictly before end of May 2017
39.820,00 € per year
Mainly Milano (Italy) and Glasgow (UK)
Flight into icing conditions remains a problematic scenario for rotorcraft. The presence of ice on the blades of the main rotor alters their geometry and increases surface roughness, resulting in the increase of drag and the premature onset of stall. These aerodynamic changes can also have dangerous effects on helicopter stability, flight condition, power/torque characteristics and component loading. Additionally, ice building up on the blades alters the weight and distribution of the aircraft, and acts to modify the inertia and aeroelastic properties of the blades themselves.
The objective of the research is to develop and analyze diverse models of variable complexity to determine the aerodynamic flow-field, the droplet trajectories and the ice accretion over a rotorcraft equipped with an anti-ice system, especially for condition where Very Large Droplets VLD may be encountered. Identify the conditions where ice can appear on the rotor and when it can be shed creating a hazard for the structural integrity.
In order to cope with the competing requirements of moderate computational efforts desired during early design phases and the interest in solution accuracy, a coupled multi-fidelity approach will be developed, bringing together a hybrid 2D/3D CFD-icing approach with a multi-body approach for the rotor dynamics. The approach considered will consider the possibility to account for the motion of the film of water along the blade as a consequence of centrifugal effects and a truly 3D heat and mass exchange during icing.
The research will exploit the library PoliMIce (Politecnico di Milano Ice accretion software) that provides a general interface allowing different aerodynamic and ice accretion software to communicate. The built-in ice accretion engine moves from the well-known Myers approach and it includes state-of-the-art ice formation models. The ice accretion engine implements a fully three-dimensional representation of the two-phase flow over the solid body, accounting for both rime and glaze ice formation. Multibody simulation of the helicopter to be coupled with CFD and ice accretion, will be based on MBDyn http://www.mbdyn.org software, developed at Politecnico di Milano.
Additionally, numerical model for ice shedding due to centrifugal forces will be developed. Such model will require the structural characterization of the different ice formations. Possible simple experimental test to validate the models will be set up during this research. Finally, the researcher will work on the development of cockpit systems to increase the pilot awareness of developing icing conditions.
This researcher will be working at the Politecnico di Milano together with University of Glasgow to obtain a double doctorate award. The ESR will develop skills in CFD/CSD modelling and simulation. The researcher will work in group with more that 20-years of experience in rotorcraft multidisciplinary design methods, developing a peculiar capability to investigate 3D complex icing problems and enhancing well established software tools. During the research, secondments are planned with Leonardo Helicopter division to gain an insight into helicopter design for icing protection, operational and regulatory challenges with respect to icing conditions. The ESR will also engage and share knowledge with other ESRs as part of the Marie Skłodowska-Curie Actions Innovative Training Network – NITROS.
• Rotorcraft dynamics
• Modelling and simulation
• Ice accretion
• Multibody systems
• Computational Structural Dynamics (CSD)
• Degree in aerospace or mechanical engineering
• Experience with CFD
• Ability to program in C/C++/Fortran
• Solid background in aerodynamics and fluid mechanics
• Solid background in structural dynamics
Type of contract
The successful ESR applicant will be offered a three year full-time funded contract by Politecnico di Milano.
Additional Eligibility criteria
English language (IELTS overall score 6.5; no sub-test less than 6.0)