Heat Transfer Enhancement in Stagnation Region of Aero-Engine Inlet Vanes due to Ejection Slot and Anisotropic Heat Conduction 2019-01-2040

Ice protection is important for aero-engine induction system, such as the inlet vanes. For the ice protection of such parts manufactured with low thermal conductivity polymer-based composite material, the combined heating method using interior jet impingement and exterior ejection film has certain advantages. The simulation model coupling CFD with solid heat conduction was developed and solved with the anisotropic thermal conductivities model to investigate the heat transfer enhancement in the stagnation region of aero-engine inlet vanes due to ejection slot and anisotropic heat conduction, which is related to the curved geometry, ejection slots and anisotropic heat conduction.

The temperature distribution and heat flux ratio between the stagnation region on outside surface and the impingement region inside were calculated and analyzed for the configuration with different ejection angle and different materials. The results show that ejection slots and anisotropic heat conduction plays important roles of the heat transfer process. For the same ejection angles, the larger the thermal conductivity, the higher the temperature at stagnation point and the better ice protection. For the same material property, the larger the ejection angle jet, the lower the temperature at stagnation point. The configuration with the ejection angle of 5 degree has the highest stagnation point temperature and have much bigger flux ratio than 1.0. This hints that the heat transfer through the slot surface in the direction of the fiber plane is dominant here. Besides that, the ratio of the composite material is almost six times higher than of the aluminum material.

This research reveals some basic heat transfer process caused by the curved geometry, ejection slots and anisotropic heat conduction and will be helpful reference for the conceptual design of such ice protection systems.