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International Journal of Rotating Machinery
Volume 2015 (2015), Article ID 679576, 13 pages
http://dx.doi.org/10.1155/2015/679576
Research Article

Flow Modeling in Pelton Turbines by an Accurate Eulerian and a Fast Lagrangian Evaluation Method

1Lancaster University Renewable Energy Group and Fluid Machinery Group, Engineering Department, Engineering Building, Bailrigg, Lancaster, Lancashire LA1 4YW, UK
2School of Mechanical Engineering, Laboratory of Hydraulic Turbomachines, National Technical University of Athens, 9 Heroon Polytechniou, Zografou, 15780 Athens, Greece

Received 26 June 2015; Accepted 21 October 2015

Academic Editor: Robert C. Hendricks

Copyright © 2015 A. Panagiotopoulos et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The recent development of CFD has allowed the flow modeling in impulse hydro turbines that includes complex phenomena like free surface flow, multifluid interaction, and unsteady, time dependent flow. Some commercial and open-source CFD codes, which implement Eulerian methods, have been validated against experimental results showing satisfactory accuracy. Nevertheless, further improvement of accuracy is still a challenge, while the computational cost is very high and unaffordable for multiparametric design optimization of the turbine’s runner. In the present work a CFD Eulerian approach is applied at first, in order to simulate the flow in the runner of a Pelton turbine model installed at the laboratory. Then, a particulate method, the Fast Lagrangian Simulation (FLS), is used for the same case, which is much faster and hence potentially suitable for numerical design optimization, providing that it can achieve adequate accuracy. The results of both methods for various turbine operation conditions, as also for modified runner and bucket designs, are presented and discussed in the paper. In all examined cases the FLS method shows very good accuracy in predicting the hydraulic efficiency of the runner, although the computed flow evolution and the torque curve exhibit some systematic differences from the Eulerian results.