Evaluation of vortex-blade interaction utilizing flow feature detection techniques

¹ Fundación ICAMCyL, León Technology Park - Main Building, 24009 León, Spain
² ASD-Altran Spain, Calle Campezo 1 - Edificio 1 28022 Madrid, Spain
³ Universidad Politécnica de Madrid - ETSIAE, Plaza Cardenal Cisneros 3 28040 Madrid, Spain
⁴ Airbus Operations, S.L., Avda. John Lennon s/n, 28906 Getafe, Spain

^* Corresponding author: n.vinha@icamcyl.com

Abstract

The extraordinary growth in computational capabilities over the last few decades has enabled the numerical simulation of massive and complex flow problems with high accuracy. Not surprisingly, CFD has become a crucial tool in the design of pioneering aircraft engine architectures, such as CROR engines. Noise and performance requirements lead the design process from a very early stage, thus requiring deep investigation of the acoustic and aerodynamic behaviour. Monitoring the trajectory of the vortices generated at the tip of the front rotating blades is of critical importance to understand and prevent vortex-blade interaction with subsequent stages, as this non-linear flow topology strongly influences the aerodynamic performance and acoustic footprints of the engine. This manuscript follows a flow feature-based approach to visualize and track these coherent structures, for the particular case of CROR. The paper starts by evaluating the suitability and performance of four typical region-based (RB) vortex detection criteria, which delimit rotating flow regions, and one line-based (LB) method that allows the reconstruction of the imaginary centre lines of the vortices. Then, two novel methodologies are introduced that improve the original assortment of seeds required by the tested LB method, as they increase the probability of these seeds to grow into a tip vortex line, providing faster and more accurate answers during the design-to-noise iterative process.