CFD Analysis of Flow Behavior in S-shape Air-Intake System of an Aircraft

Abstract

The project aims at investigating the flow behavior in an S-shape air-intake of an aircraft using the help of Computational Fluid Dynamics. S-shape air-intake is used in many aircraft like Boeing-727, Eurofighter Typhoon. In an S-duct, due to the change in the geometry at sections, there is origin of secondary flow which results in the total pressure drop. The variations in different flow parameters like static pressure, total pressure, Mach number along the duct length were studied. In this study, two cases are studied using a simple S-duct configuration and a modified S-duct configuration. The S-shape intake is modified by installing the guide vanes near the throat section of the duct. The angle of incidence is changed for the guide vanes from 0°, 8°and 16°. The modification in the duct is done to decrease the total pressure loss at the engine face and to improve the total pressure recovery. The two configurations were solved for different Mach numbers (0.4, 0.5, 0.6, 07, and 0.8) and two flights angle of attack 0° and 10°respectively. For the first configuration a structures grid is generated in GridZ where as for the second configuration an unstructured grid is generated in ICEM-CFD meshing software. To obtain the best results near the boundary of the intake, clustering operation was done for the structured grid whereas; a prism layer was generated for the same purpose in the T-Grid software. The computation of both the configurations was done in CFD-Expert-Lite solver. All the cases were run using Spalart Allmaras turbulence model.