Master thesis and internship[BR]- Master's thesis : Front blade optimisation of a critical tandem stator[BR]- Integration internship

Abstract

In the context of improving axial compressor efficiency in turbojet engines, the Outlet Guide Vane (OGV), located at the end of the low-pressure compressor, plays a crucial role in reorienting the flow axially to ensure optimal conditions for the downstream high-pressure compressor. However, during off-design operation, the inlet flow angle can vary significantly, which may cause flow separation, increase the pressure losses, and decrease the performances. The goal of this thesis is therefore to find an optimised variable tandem OGV geometry by adjusting the rotation strategy of the front blade. To achieve this goal, a tandem blades system with a variable stator vane (VSV) on the front blade was considered to enlarge the range of acceptable incidences. The study explores how the rotation of the front blade around different pivot points can significantly enhance the compressor stage’s performance across a wide incidence range. Using the genetic software Minamo, an automated process was implemented to determine the total pressure losses and the static pressure gain, by optimally rotating the front blade to a large range of inlet flow angles, given the position of the front blade and the pivot point. The results were obtained through 2D RANS simulations, performed with SU2. As a starting point, one static and two rotating configurations from M. Brach’s thesis [1] were used: rotation around the trailing edge and the mid-chord. The first one offers very good performances while the second one presents a more practical application to manufacture. Despite its limitations, mostly due to the 2d simulation geometry and the stationnary RANS model used, this work demonstrates the potential improvements achievable with optimisation-driven designs in variable tandem blades OGV.