14th European Conference on Turbomachinery Fluid dynamics & Thermodynamics

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Axial Turbines


Andrea Cassinelli - Imperial College London
Andres Mateo - Universidad Politécnica de Madrid
Francesco Montomoli - Imperial College London
Paolo Adami - Rolls-Royce
Raúl Vázquez Díaz - Rolls-Royce
Spencer Sherwin - Imperial College London


RANS methods will continue to be the backbone of CFD-based design, but the recent development of high-order unstructured solvers and meshing algorithms, combined with the lowering cost of HPC infrastructures, has the potential to allow for the introduction of high-fidelity simulations in the design loop, taking the role role of a virtual wind tunnel [1]. Extensive validation and verification is required over a broad design space.This is challenging for a number of reasons, including the range of operating conditions, the complexity of industrial geometries and their relative motion. Building on the knowledge previously reported [2], a representative industrial low pressure turbine (LPT) cascade subject to wake passing interactions is analysed, adopting the incompressible Navier-Stokes solver implemented in the spectral/hp element framework Nektar++. The bar passing effect is modelled by leveraging a spectral-element/Fourier Smoothed Profile Method [3]. A series of auxiliary numerical experiments were carried out to ensure the generation of a realistic cylinder wake, shown qualitatively in the Figure at Re=300000. The Reynolds sensitivity is analysed, focusing in detail on the dynamics of the separation bubble on the suction surface as well as mean flow properties and turbulence kinetic energy budgets.The main findings are compared with experimental data, showing remarkable agreement in the prediction of wake traverses and losses. [1] G. M. Laskowski, et al. (2016) "Future Directions of High Fidelity CFD for Aerothermal Turbomachinery Analysis and Design" 46th AIAA Fluid Dynamics Conference. [2] A. Cassinelli, F. Montomoli, P. Adami and S. J. Sherwin (2018) "High Fidelity Spectral/hp Element Methods for Turbomachinery" ASME Paper No. GT2018-75733. [3] Z. Wang, M. S. Triantafyllou, Y. Constantinides, and G. E. Karniadakis (2018) "A spectral-element / Fourier smoothed prole method for large-eddy simulations of complex VIV problems", Computers and Fluids, vol. 172, pp. 84-96.

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