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Start Over Author "Chen, Zhongfei" Publisher elsevier bv
86 results on '"Chen, Zhongfei"'

42. Performance optimization of a coaxial-cylinder wave energy converter

Author

Binzhen Zhou, Malin Göteman, Chen Zhongfei, Peng Jin, and Liang Zhang

Subjects
Wave energy converter, Physics, 020209 energy, Mechanical Engineering, Acoustics, Process (computing), Stiffness, 02 engineering and technology, Building and Construction, Mooring, Pollution, Industrial and Manufacturing Engineering, Power (physics), Generator (circuit theory), General Energy, 020401 chemical engineering, Frequency domain, 0202 electrical engineering, electronic engineering, information engineering, medicine, Range (statistics), 0204 chemical engineering, Electrical and Electronic Engineering, medicine.symptom, Civil and Structural Engineering
Abstract

To achieve a wider frequency range where the device has a larger capture width ratio, the performance of a heaving coaxial-cylinder wave energy converter is optimized through actively controlled generator damping and stiffness using a linear frequency domain model. The generator power take-off system is modeled as a damping-spring system, and the numerical model is validated against published results. The coupled dynamics of a two-body model is analyzed to search for the optimal generator damping and stiffness leading to maximal capture width ratio. The optimization process, which can be decoupled into two independent steps, leads to an improved performance of the device, with increased frequency bandwidth and better capture width ratio. The effects of water depth, mooring stiffness, and the dimensions of the WEC on the capture width ratio are also studied, and parameter values are identified which correspond to optimal performance of the device.

Published
2019

48. Performance evaluation of a dual resonance wave-energy convertor in irregular waves

Author

Chen Zhongfei, Binzhen Zhou, Liang Zhang, Xuewei Zhang, and Liang Sun

Subjects
Physics, Absorption (acoustics), 020209 energy, Stiffness, Resonance, 020101 civil engineering, Ocean Engineering, 02 engineering and technology, Mechanics, 0201 civil engineering, Power (physics), Airy wave theory, Spring (device), 0202 electrical engineering, electronic engineering, information engineering, medicine, medicine.symptom, Energy (signal processing), Wave power
Abstract

A new waterproof point absorber, named Dual Resonance wave-energy convertor (DR-WEC), is put forward in this paper. A geometry with low viscous effect is adopted for the waterproof outer floater of DR-WEC and two resonance frequencies can be found due to the existence of two sets of mass-spring subsystems. The motions and absorbed power of the DR-WEC in regular and irregular waves are investigated using the linear wave theory and the spectral analysis method with viscous effect being considered. The influence of three mechanical parameters, i.e., the internal mass, stiffness of spring and damping of power-take off (PTO) system, on the capture width ratio is studied. The mechanical parameters can affect the shapes of power response curves, which bring the possibility to enhance the wave power absorption by manipulating these parameters according to the characteristics of encountered waves. The Generalized Pattern Search (GPS) algorithm is employed to find these optimal mechanical parameters in both short-term and long-term sea states. The numerical results have confirmed that not all of the three mechanical parameters are needed to vary during operation. Some of the three parameters can be fixed for the balance of cost efficiency and wave power absorption. When the number of variable mechanical parameters is two, one, and zero, declinations of the annual average power relative to that with three are 4.1%, 13.0%, and 36.4%, respectively. At last, solutions for realizing an internal parameter-variable mechanism are discussed.

Published
2018

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