No abstract

A new approach using the Level-Set framework is developed in the NSMB (Navier-Stokes Multi-Block) compressible solver for modeling the ice/air interface evolution through time during in-flight icing. Droplet distribution and impingement efficiency are computed by an Eulerian approach and the accreted ice is calculated by a PDE model. An icing velocity field is introduced and the Level-Set equations are solved on body-fitted multi-block structured grids. The whole process is parallelized with the MPI library for efficient calculations. Single step icing is simulated on NACA23012 and NACA0012 airfoils and on the ONERA-M6 and the GLC-305 swept wings. In all the studied cases, the results are in good agreement with existing and available data validating the feasibility of the approach.

Purpose This paper aims to assess the strengths and weaknesses of four thermodynamic models used in aircraft icing simulations to orient the development or the choice of an improved thermodynamic model. Design/methodology/approach Four models are compared to assess their capabilities: Messinger, iterative Messinger, extended Messinger and shallow water icing models. They have been implemented in the aero-icing framework, NSCODE-ICE, under development at Polytechnique Montreal since 2012. Comparison is performed over typical rime and glaze ice cases. Furthermore, a manufactured geometry with multiple recirculation zones is proposed as a benchmark test to assess the efficiency in runback water modeling and geometry evolution. Findings The comparison shows that one of the main differences is the runback water modeling. Runback modeling based on the location of the stagnation point fails to capture the water film behavior in the presence of recirculation zones on airfoils. However, runback modeling based on air shear stress is more suitable in this situation and can also handle water accumulation while the other models cannot. Also, accounting for the conduction through the ice layer is found to have a great impact on the final ice shape as it increases the overall freezing fraction. Originality/value This paper helps visualize the effect of different thermodynamic models implemented in the same aero-icing framework. Also, the use of a complex manufactured geometry highlights weaknesses not normally noticeable with classic ice accretion simulations. To help with the visualization, the ice shape is presented with the water layer, which is not shown on typical icing results.