Application of Extended Messinger Model for Ice Accretion on Complex Geometries

Ice accretion can significantly degrade the performance, stability, availability, and affordability of an airborne vehicle. It is imperative that this phenomenon be modeled accurately. While ice accretion studies have been performed on airplane wings, propellers, and helicopter blades, there are very few attempts to model the process on more complex geometries such as fuselages. In this study, an existing in-house Extended Messinger methodology is generalized for complex geometries by modeling the flow field and water droplet transport on unstructured grids, and carrying out the ice accretion calculations along surface streamlines. A general framework has been developed, allowing the use of two-dimensional and three-dimensional, structured, and unstructured, public domain and commercial CFD analyses. The methodology is primarily spilt into three steps: the continuum flow field analysis, the dispersed water phase computations, and the ice accretion module. In the present study, in-house methodologies as well as commercial solvers such as STAR-CCM+ and ANSYS Fluent have been used for the flow field and droplet dispersed phase computations. The in-house methodologies for the dispersed water droplet transport are done using an Eulerian approach, with a one-way interaction between the air flow and the dispersed phase via the drag force exerted on the droplets by the air flow. The ice accretion is carried out along surface streamlines, or optionally along two-dimensional section cuts, using an in-house icing methodology based on the Extended-Messinger model. The predictions from the present approach are compared to available experimental data, and predictions using other solvers such as LEWICE and STAR-CCM+. Several configurations with varying levels of complexity are modeled. These include 2-D airfoils, swept wings, and helicopter fuselage configurations. Time and space sensitivity studies have been done.Ph.D