Session: Student Poster Competition

Submission Number: 186885

A Hierarchy of Computational Methods for Aerodynamic Analysis and Optimization of Aeronautical Propellers 

Within the decarbonization effort of the aeronautic community, turboprop engines are regaining a primary role in regional aircraft propulsion, without citing the adoption of electric-powered propeller aircraft for very short range. In such a context, it is therefore necessary to be able to design, analyze, and optimize rotors with very different features, where the driving factor is an efficient match with the airframe. In order to significantly improve the aerodynamic, aeroacoustic, and structural performance, it is essential to implement CFD analysis as accurately as possible while maintaining an adequate computational cost, and using them together with advanced multi-physics optimization algorithms. This poster aims to present the latest developments in numerical methods with low- to mid- level of fidelity for the design and optimization of aeronautical propellers. The current state-of-the-art in propeller numerical modelling relies on a first class of lower order methods derived from the Blade Element Momentum Theory (BEMT), which are extensively used for design purposes and are based on external calibration tables. High-speed rotors are typically investigated with higher accuracy techniques based on Unsteady Reynolds Averaged Navier-Stokes (URANS) solutions, Large Eddy Simulations (LES), or VLES in the context of Lattice-Boltzmann solvers. The first class allows for low computational cost but needs further development to capture interaction effects. Nevertheless, such methods are particularly well suited for integration within advanced optimization strategies that enable the accurate parametrization of the blade’s complex three-dimensional geometry by handling several decision variables. The second class is less limited and more accurate, but the computational cost can become prohibitive without an adequate simulation infrastructure. A third class of methods, referred to as multi-fidelity techniques, aims at combining the scale-resolving capabilities of high-order models and their accurate representation of compressible flows with a physics-based modelling of propeller forces, implementing source-term methods within finite volume or high-order finite difference solvers. First, the poster illustrates the application of an in-house code implementing the reformulated Blade Element Momentum Theory (rBEMT) for the analysis of both full-scale propellers and small-scale geometries operating under laminar–turbulent transition conditions. Several correction models accounting for tip-loss and compressibility effects are implemented within the code. An investigation of the model accuracy as a function of the adopted correction setup is presented. Furthermore, the application of this method within two different multi-level optimization strategies is also discussed. In particular, such a class of geometric optimization aims to maximize the propeller blade performance by decoupling the planform and sectional design into distinct optimization steps. The findings highlight the capability of the proposed framework to explore design geometries beyond the limitations of traditional approaches, showcasing its potential for advancing blade shape optimization during the initial design stage. Moreover, the poster presents the implementation of a multi-fidelity RANS/BET method. This framework adopts a body-forces approach and is based on the coupling of a CFD solver with the Blade Element Momentum Theory (BEMT) routine. Such an approach enables the analysis of propellers under both isolated and installed conditions, and for both axisymmetric and non-axisymmetric flow regimes. The low-fidelity routine includes two tip-loss models and a compressibility model. This approach avoids the need for an exact geometric representation of the blade by replacing its influence on the flow with a distribution of forces. The code has been successfully validated on the XPROP-S small-scale propeller, developed at TU Delft, and is currently being further investigated and refined to enhance its computational efficiency. The expected scientific impact is to evolve the current capabilities for design and analysis of electric distributed propulsion, turboprop engines and open rotor configurations, being part of the Clean Aviation Strategic Research Innovation Agenda (SRIA) for the path towards net-zero carbon emissions by 2050.

Presenting Author: Andrea Magrini Università Degli Studi di Padova

Presenting Author Biography: Andrea Magrini is an Assistant Professor at the University of Padova.
His research is focused on turbomachinery for propulsion, mainly in aeronautics and using computational fluid dynamics (CFD). In particular, the themes involve the analysis, design, and aeropropulsive optimisation of propulsors, the installation effects and the engine/airframe interaction, and novel propulsive configurations with inlet distortion conditions.

Authors:

Manuel Casablanca Università Degli Studi di Padova
Andrea Magrini Università Degli Studi di Padova
Ernesto Benini Università Degli Studi di Padova