<div class="section abstract"><div class="htmlview paragraph">Icing related problems on aero-components have been recognized since the beginning of modern aviation. Various icing incidents occurred due to severe degradation of aerodynamic performance, and engine rollbacks. As in-flight icing can occur over a broad range of atmospheric and flight conditions, design of effective ice protection mechanisms on aero-components is essential. Computational simulations are a significant part of designing these mechanisms, therefore accurate prediction of droplet collection efficiency and accreted ice shapes are vital. In the current study, continued efforts to improve a computational in-flight icing prediction tool are introduced together with obtained results. The emphasis in this study is on the recent improvements introduced to flow-field and droplet trajectory calculation modules. The flow-field predictions were previously managed by Hess-Smith panel method and this module is fortified with inclusion of an open-source Navier-Stokes code. Droplet trajectories were being computed with Lagrangian method and now a finite volume based Eulerian droplet trajectory tracking model with explicit scheme is also available. In order to evaluate the performance of these major updates, code validation results are presented on various aero-components including a clean MS(1)-0317 supercritical airfoil, a clean NACA23012 airfoil along with 3 simulated ice shapes mounted on, a multi-element airfoil, an axisymmetric engine inlet and an inertial particle separator. Results obtained by Eulerian model are compared with experimental data from open literature and existing Lagrangian method findings when applicable. Present study and the results show that developed approach has potential in terms of computational time, accuracy and suitability for complex aero-component analysis.</div></div>

Esentepe Mah. C ƒ evreyolu Blv., Tepebaƒ sŠ, Eskiƒ sehir 26003, TurkeyIce shape predictions for a NACA0012 airfoil and collection e©ciency predictions for the Twin Otter airfoil are obtained and presented. The results are validated with reference numerical and experimental data. Ice accretion modeling mainly consists of four steps: §ow ¦eld solution; droplet trajectory calculations; thermodynamic analyses; and ice accretion simulation with the Extended Messinger Model. The models are implemented in a FORTRAN code to perform icing analyses for twodimensional (2D) geometries. The results are in good agreement with experimental and numerical reference data. It is deduced that increasing computational layers in calculations improves the ice shape predictions. The results indicate that collection e©ciencies and impingement zone increase with increasing droplet diameter.

There are different characters of air flow in a conventional gas turbine blade cooling channel. These flow characters; including high streamline curvature caused from 180 degree bends, sequential flow separations caused from rib turbulators and pin-fin structures are analyzed separately with available commercial software for different turbulence models and validated against reliable experimental data from open literature. Also coupled conjugate heat transfer analyses on NASA C3X vane, which has only radial holes through blade span for cooling, are conducted with the same turbulence models. The accuracy information gathered from all these analyses; each interested with a single character of air and coupled conjugate heat transfer are put together and applied to a conjugate numerical analysis of internally cooled (VKI) LS-89 turbine blade. Internal cooling scheme which is applied to (VKI) LS-89 turbine blade encompassed the aforementioned flow characters and analyses are performed under realistic conditions. Because of the high temperature values occurring at realistic conditions, thermal conductivity and specific heat capacity of air and metal (Inconel 718) are modeled as temperature dependent material properties instead of using constant values. Conducted research revealed that 4 eqn. V2-f turbulence model gives similar results compared to the 2 eqn. Realizable k-e, k-w SST turbulence models for 180 degree bend and rib turbulator cases. However, at NASA C3X vane analyses V2-f turbulence model results are far more accurate than other two turbulence models in the manner of heat transfer coefficient and surface temperature distribution.

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