Computational design and static-structural analysis of a small-scale turbojet propulsive engine for an unmanned aerial vehicle

Abstract

This study focused on the computational design and static structural analysis of a small-scale turbojet engine (SSTE) that can power an unmanned aerial vehicle with a thrust of 50 N at a speed of 8000 rpm. SOLIDWORKS 2018 was used to design the CAD geometry of the SSTE, and to carry out a CFD analysis on the compressor to determine the pressure distribution across the compressor and the compressor pressure ratio. The obtained pressure ratio was further used to carry out a structural analysis of the SSTE with emphasis on the turbine component using ANSYS static structural module. This analysis was done to determine the level of deformation of the chosen design material (stainless steel grade 310), the maximum and minimum stresses, factor of safety, and its fatigue life. Design and CFD results obtained shows that the design as well as the pressure distribution in the compressor is reliable. The 50N small scale turbojet engine showed higher optimum performance from structural design and evaluation when compared to that of the 70N thrust jet cat model. Results of the structural analysis shows that the turbine blades will experience minimum and maximum deformation of 0 m and 2.2543×10⁻⁵ m at the leading edges and trailing edges of the blade chord respectively. Also, maximum and minimumstresses will occur at 1.0632×10⁵ Pa and 6.7192×10⁷ Pa respectively. Conversely, the factor of safety was within 3.0807 to 15 which show that the design is adequate. Additionally, considering the fatigue life, the SSTE is bound to fail completely at approximately 1.929×10⁷ months. Therefore, the SSTE with the materials suggested above is capable ofpropelling an unmanned aerial vehicle considering the results obtained.

Keywords: Computational, static-structural, turbojet, UAV, design