ОПТИМІЗАЦІЯ НОСОВОЇ ЧАСТИНИ ФЮЗЕЛЯЖУ З ТОЧКИ ЗОРУ АЕРОДИНАМІКИ ЛІТАКА

Abstract

The paper represents the analysis intended to optimize the fuselage nose section with regard to aircraft aerodynamics in the process of development of an unmanned transport aircraft (UTA). The article deals with provisions of high aerodynamic efficiency that cannot be achieved without proper selection of the shape and optimal fuselage parameters that determine mutual interference of aircraft components and units. When analyzing the flow improvement around the fuselage nose in flight, three fuselage versions were considered listed further: 1) a prototype for testing automatic flight control systems with participation of pilots; 2) a nose symmetrical relative to the fuselage rocket type cylinder axis; 3) a supposedly optimal variant based on the results of previous calculations. The aerodynamic characteristics of 3D fuselage models for positive integer Reynolds numbers (full-scale model) were calculated using the ANSYS software package. Three computational grids were built for these models in ANSYS ICEM CFD. The given version of the fuselage nose section intended for testing automatic flight control systems with participation of pilots initially has the greatest resistance among the considered variants. That is, first variant of the fuselage nose gives substantial braking zone as well as significant flow acceleration zone exists in place where fuselage is transformed into cylindrical part. The variant with the nose section symmetrical relative to the rocket type cylinder axis has smaller braking zone and less dispersed flow in place where fuselage is transformed into cylindrical part and, therefore, it has lower resistance in comparison with the first version. The fuselage execution developed on the basis of the results of previous calculations, despite the extensive acceleration zone at the junction of the nose to the cylindrical part, has shown the least resistance, respectively, and is the best of the considered variants. This is also confirmed by a comparison of streamlines over the nose surface. The streamlines are given for calculations at angle of attack of 8°; at this angle of attack, the difference in the coefficient Cx is clearly visible.