Performance prediction of cavitating marine current turbine by BEMT based on CFD

Mehmet Salih Karaalioglu*, Sakir Bal

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

In the present study, the hydrodynamic performance of cavitating and non-cavitating marine current turbines (MCTs) has been investigated by blade element momentum theory (BEMT) coupled with Reynolds-averaged Navier–Stokes (RANS) technique. Before employing the BEMT, two-dimensional (2-D) lift and drag forces of cavitating and non-cavitating sections of MCT have been computed by RANS. The lift and drag forces, including cavity shapes, depend on Reynolds number (Re), cavitation number, and angle of attack. The hydrodynamic characteristics of cavitating 2-D hydrofoils (sections) were calculated via a multiphase solver “interPhaseChangeFoam” from the open-source code OpenFOAM. Cavitating flow simulations around a hydrofoil were carried out with Shear Stress Transport (SST) k−ω turbulence and Schnerr–Sauer cavitation model. The grid convergence index (GCI) was applied to confirm the numerical accuracy of the simulations. Validation of the proposed BEMT model has been done with two different model MCTs under non-cavitating conditions. Then, cavitating flow over a hemispherical head-form axisymmetric body, the NACA 66, and the Clark-Y were selected to evaluate the accuracy of the numerical methods and turbulence models available in the solver. Then, cavitating National Renewable Energy Laboratory (NREL) S814 2-D hydrofoil was later simulated for various Reynolds numbers, cavitation numbers, and angles of attacks. By using cavitating NREL S814 2-D hydrofoil data, the cavitation phenomenon was included in the method of BEMT. The distribution of cavitation on the blade has been modeled with BEMT coupled with RANS. Power coefficients at a wide range of tip speed ratios, including cavitation distribution on turbine blades obtained from BEMT, have been compared with each other and experiments. A reliable agreement has been found for all cases studied here. It is shown that cavitation has a negative effect on the power output of MCT for all tip speed ratios and cases discussed in this study. In addition, under cavitating conditions, the tip speed ratio of the operation point that corresponds to the highest power coefficient shifts to the right side of the power curve.

Original languageEnglish
Article number111221
JournalOcean Engineering
Volume255
DOIs
Publication statusPublished - 1 Jul 2022

Bibliographical note

Publisher Copyright:
© 2022 Elsevier Ltd

Funding

This research was supported by the Coordination Unit of Scientific Research Projects of Istanbul Technical University, Turkey (Project number: MDK-2018-41535 ). Computing resources used in this work were provided by the National Center for High Performance Computing of Turkey (UHeM) under grant number 4007182019 .

FundersFunder number
National Center for High Performance Computing of Turkey
Ulusal Yüksek Başarımlı Hesaplama Merkezi, Istanbul Teknik Üniversitesi4007182019
Istanbul Teknik ÜniversitesiMDK-2018-41535

    Keywords

    • Blade element momentum theory
    • Cavitation
    • Marine current turbine
    • OpenFOAM
    • Panel method

    Fingerprint

    Dive into the research topics of 'Performance prediction of cavitating marine current turbine by BEMT based on CFD'. Together they form a unique fingerprint.

    Cite this