![Sample our Engineering & Technology journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5933/TOC-Subject-Sample-2021-Engineering-Tech.jpg"})
ABSTRACT
In order to explore the energy harvesting performance of the semi-active flapping airfoil, a new semi-active flapping airfoil power generator (FAPG) using the coupling of the ratchet and gear pinion as transmission mechanism was developed. The influence of the pitching amplitudes, pitching axis positions, and pitching periods on the energy harvesting performance of the semi-active FAPG was explored systematically by the orthogonal experiment and computational fluid dynamics simulation method. The experimental results indicated that the pitching amplitude, pitching axis position, and pitching period can significantly influence the energy harvesting performance of the semi-active FAPG. Under wind speed of 3, 4, and 5 m/s, the mean net output power of the semi-active FAPG reaches 0.026, 0.0297, and 0.0318 W, respectively. It was also found that compared with the pitching amplitude and the pitching axis position, the pitching period has the greatest influence on the mean net output power. Through the deep analysis of the flow fields around the semi-active flapping airfoils with different parameter combinations, it was found that the optimized parameter combinations can delay the shedding of the trailing edge vortex generated by the flapping airfoil during pitching motion, and make the separated leading edge vortex generated during the plunging motion reattaching again on the surface of the flapping airfoil, which leads to have better energy harvesting performance of the generator.
Nomenclature
| U∞ | = | Inlet wind speed (m/s) |
| θm | = | Pitching amplitude (°) |
| L | = | Distance between the leading edge and pitching axis (m) |
| d | = | Chord length (m) |
| Hm | = | Plunging amplitude (m) |
| θ | = | Pitching angle (°) |
| T | = | Motion period (s) |
| Tθ | = | Pitching period (°) |
| PH | = | Output power (W) |
| Pθ | = | Pitching consumption power (W) |
| = | Mean output power (W) | |
| = | Mean pitching consumption power (W) | |
| MH | = | Torque of output shaft (N·m) |
| ωH | = | Angular velocity of output shaft (rad/s) |
| Mθ | = | Pitching torque of flapping airfoil (N·m) |
| ωθ | = | Pitching angular velocity (rad/s) |
| ρ | = | Fluid density (kg/m3) |
| s | = | Span length (m) |
| G | = | Mean value of the mean net power coefficient (1) |
| E | = | EInfluence index of factor (1) |
| CL | = | Lift coefficient (1) |
| CM | = | Drag coefficient (1) |
| Acronyms | = | |
| CFD | = | Computational fluid dynamics |
| FAPG | = | Flapping airfoil power generator |
| UDF | = | User-definedfunctions |
| S-A | = | Spalart–Allmaras |
| PISO | = | Pressure-Implicit with Splitting of Operators |
Acknowledgements
The present study was supported by the National Natural Science Foundation of China (project No. 51975429).
Disclosure statement
No potential conflict of interest was reported by the authors.
Author contributions
ZHANG Jiacheng designed the research and wrote the draft of manuscript. ZHU Jianyang helped to supervise and administrate the project. Jiang Lin and ZHAO Hui helped to organize the manuscript.
Additional information
Funding
Notes on contributors
Zhang Jiacheng
Jiacheng Zhang received his B.S. in School of Mechanical Engineering from Harbin University of Science and Technology, China, in 2018. He received his M.S. degree in School of Mechanical Engineering from Wuhan University of Science and Technology in 2021. He is currently a PhD candidate in the same school. His research interests include fluid dynamics and fluid–structure interaction.
Zhu Jianyang
Jianyang Zhu received his B.S. and M.S. degrees from Harbin Institute of Technology University, China, in 2006 and 2008, respectively, and his PhD in Fluid Machinery and Engineering in 2014. He is currently a professor of Machinery and Automation at Wuhan University of Science and Technology in Wuhan, China. His research interests include fluid–structure interaction, fluid dynamics, and heat transfer.
Jiang Lin
Lin Jiang graduated from the Harbin Institute of Technology, China, in 2008 and received his PhD. Now he works as a professor in Wuhan University of Science and Technology. He is a doctoral supervisor. His research interests include mobile robot mapping, localization, and navigation.
Zhao Hui
Zhao Hui Received her B. Sc. (Eng.) in 1995 and M.Sc. (Eng.) in 1997 and Dr. Tech. in 2000 from Harbin Institute of Technology (HIT), China. She has been involved in numerous research projects, including National Science and Technology Major Project of China, all kinds of hydraulic-actuated simulators,etc. She got her professor position in 2009 and as a visiting scholar from 2009 to 2010 in MAHA Fluid Power Research Center, Purdue University, USA. She is currently a Professor both in the College of Machinery and Automation (CMA) and in the Institute of Robotics and Intelligent Systems (IRIS) of Wuhan University of Science and Technology (WUST). Her research interests include bionic and intelligent robot, fluid power, and servo control.