Application of Extended Messinger Icing Models to Complex Airframe Geometries 2020-01-0022
Ice accretion poses a major problem for civilian and military aircraft and rotorcraft, severely jeopardizing the safety and survivability of the vehicle. The development of analytical and empirical ice tools to understand the ice accretion process is crucial. Existing methodologies, such as the Messinger model employed by LEWICE, are able to predict ice shapes and growth on lifting surfaces such as wings and rotors relatively well. Extension of these methodologies to more complex configurations is needed. The methodology must be reasonably modular so that one can leverage future developments in computational fluid dynamics, structured and unstructured grid generation, and ice accretion models.
Towards this goal, the following modular approach has been developed.
1. Do the unstructured grid based flow analysis. Save the grid and flow field in a standard format such as Plot3D or VGrid.
2. Compute the water particle transport using either the Lagrangian approach or an Eulerian approach. Where possible, public domain analyses, e.g. OpenFoam, are used in this step.
3. Compute the time rate at which water is deposited on the solid surface from Step 2.
4. Track surface streamlines from oil flow visualization (use either a flow visualization software, or public domain tools).
5. Integrate the ice growth along the surface streamlines using our extended Messinger model or LEWICE.
6. Periodically add the accreted ice to the solid geometry, repeat steps 1-6.
These tools are being coupled to each other with the aid of a Python script in a seamless fashion.
The full paper will present details of this approach, and present code validation studies for a number of configurations – helicopter fuselage, 3-D swept wings, and two-bladed teetering tail rotors in forward flight.
Avani Gupta, Lakshmi Sankar, Richard Kreeger
Georgia Institute of Technology, NASA John Glenn Research Center