Free and Forced Vibration Analysis of H-type and Hybrid Vertical-Axis Wind Turbines

Minhui Tong; Weidong Zhu; Xiang Zhao; Meilin Yu; Kan Liu; Gang Li

doi:10.3390/en13246747

Energies (Dec 2020)

Free and Forced Vibration Analysis of H-type and Hybrid Vertical-Axis Wind Turbines

Minhui Tong,
Weidong Zhu,
Xiang Zhao,
Meilin Yu,
Kan Liu,
Gang Li

Affiliations

Minhui Tong: Logistics Engineering College, Shanghai Maritime University, Shanghai 201306, China
Weidong Zhu: Department of Mechanical Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
Xiang Zhao: Department of Mechanical Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
Meilin Yu: Department of Mechanical Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
Kan Liu: Department of Mechanical Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
Gang Li: Department of Mechanical Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USA

DOI: https://doi.org/10.3390/en13246747
Journal volume & issue: Vol. 13, no. 24
p. 6747

Abstract

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Vertical-axis wind turbines (VAWTs) are compact and efficient and have become increasingly popular for wind energy harvesting. This paper mainly focuses on free and forced vibration analysis of two different types of VAWTs, i.e., an H-type VAWT and a new hybrid VAWT. The H-type VAWT has a lower cost, while the hybrid VAWT has a better self-starting capability at a low wind velocity. Both of them can be used for wind energy harvesting. By using the assumed modes method, the two VAWTs are simplified by a single degree-of-freedom (SDOF) model. By utilizing the method of structural mechanics, a multi-degree-of-freedom (MDOF) model is developed for the two VAWTs and the turbines in them are reasonably simplified. Natural frequency analyses for the SDOF and MDOF models of the two VAWTs are conducted. A beam element model (BEM) of the two VAWTs is created to calculate their natural frequencies and mode shapes and to verify natural frequency results from the SDOF and MDOF models. By using the BEM of the two VAWTs, their amplitude-frequency responses are obtained from harmonic response analysis. To analyze forced vibrations of the two VAWTs, aerodynamic loads on the two VAWTs are obtained from computational fluid dynamics (CFD) simulation. By using solid element models of the two VAWTs, forced transient responses of the two VAWTs are calculated by using the aerodynamic loads from CFD simulation. Steady-state forced response amplitudes of the 1 m-mast hybrid VAWT are 23.8% and 20.5% smaller in X- and Y-directions than those of the 1 m-mast H-type VAWT, respectively. Frequency contents of the aerodynamic loads from CFD simulation are calculated, which confirm that they are periodic, and the power efficiency of the H-type VAWT is about 2.6% higher that of the hybrid VAWT.

Published in Energies

ISSN: 1996-1073 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology
Website: http://www.mdpi.com/journal/energies

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