Analysis on Aerodynamic Characteristics of Blunt Trailing Edge Wind Turbine Airfoil
CHENG Xiaolong1, MA Chaochen1, LAO Dazhong2, WANG Leilei1, YANG Ce1
(1. Turbo Machinery Institute, School of Machanical Engineering, Beijing Institute of Technology, Beijing 100081; 2. School of Aerospace Scientific Engineering, Beijing Institute of Technology, Beijing 100081)
Abstract: In this issue，a blunt trailing edge wind turbine airfoil TR-4000-2000 is numerically investigated by the Computational Fluid Dynamics software FLUENT in the case of k-ε turbulent model，and the influence caused by the use of blunt trailing edge on aerodynamic characteristics were studied. Steady and unsteady numerical simulation of airfoil flow field in different attack corner was performed，and the fluctuation characteristics of aerodynamic parameters was obtained，such as lift coefficient，drag coefficient and time-dependent pressure on airfoil surfaces. Besides，the periodic movement of shedding vortex and separation vortex was gained，and the corresponding relationship between fluctuation of lift coefficient，drag coefficient，trailing edge vortex movement and surface pressure fluctuation was determined by the way of frequency analysis. The analytic results show that the pressure fluctuation on airfoil surface caused by shedding vortex in trailing edge is the main reason of aerodynamic characteristics fluctuation. Based on these researches，an overall explanation was given to the characteristics of fluid field and its transformation rules，which build the foundation for further research such as lift improvement and drag reduction，stall control and flow control.
Key words: Blunt trailing edge airfoil；Numerical simulation；Lift and drag characteristic；Pressure fluctuation
Low Power Non-isolated Single-Switch Double Buck Three-Port Converter
WEN Gang, CHEN Yu, KANG Yong
(State Key Laboratory of Adwanced Electromagnetic Engineering Technology (AEET) also School of Electrical and Electronic Engineering (SEEE), Huazhong University of Science & technology, Wuhan 430074)
Abstract: A new double buck three-port converter using in low power non-isolated application is presented in this paper. This new converter uses one power switch to control two buck circuits working independently, and can be used in the renewable energy systems to connect the new energy resource, energy storage element and load. The attractive features are: (1) only have one power switch, so the drive circuits are simple, the cooling system is small, and the cost of the device is low; (2) the duty cycle and switching frequency are utilized for balancing the energy among the three ports, and control circuit is simple; (3) the lifespan of the energy storage element can be prolonged, since there is a direct current path from source to load and just the redundant energy need to be processed. The circuit configuration, working modes, and the design method of the converter are introduced, a suitable variable-band sliding-mode controller is proposed, the energy management strategy is analysed, and at last the experimental results are given to prove the theoretical analysis' s validity.
Key words: three-port converter; renewable energy system; energy management; sliding-mode control
High-order Siliding Mode Control of Doubly-fed Induction
Chen Bin, Feng Yong, Zhou Minghao
(School of Electrial Engineering and Automation,Harbin Institute of Technology,
Abstract: Doubly-fed induction generator is the most important generator used for VSCF wind power generation system. so researching on new control strategy to ensure safe, stable and efficient operation of DFIG has important meaning. As DFIG is a multiple variables, strong coupling and nonlinear system, which makes it difficult to use traditional linear control strategy to control the DFIG with good dynamic and static performance. High-order sliding mode control strategy has many important advantages, such as strong robustness，fast convergence，high
tracking accuracy and ability to eliminate the chattering phenomenon existing in the conventional sliding mode control. In this paper, speed and current controllers of DFIG are designed based on the mathematical mode of DFIG in d-q synchronous rotating reference frame and the high-order sliding mode control theory. The validity of the proposed method has been verified by computer simulation.
Keywords: Wind power; Vector control; High-order sliding mode control
The Comparison And Analysis In The Field Of Isotope Separation Based On PIC
Yan Yuming, Zhao Hailong, Wang Yulong, Zhang Le, Jiang Binhao
(Department of Electrical Engineering School of Electrical Engineering and Automation, Harbin Institute of Technolog, Harbin 150001)
Abstract: Plasma optical mass separation method inherits the advantages of traditional electromagnetic isotope separation method, the theory is an important reformation in the area of isotope separation. The azimuthator is an important part of the mass separator, and the particle-in-cell method is one of the three important methods in the study of plasma. Based on brief analysis to the existing particle-in-cell simulation software, it takes the azimuthator of plasma optical mass separation as the research object, contrasts the simulation results of opening particle-in-cell software OOPIC and the PIC program written by own using the research method of PIC, and analyse the merits and faults of them.
Keywords: POMS; azimuthator; plasma beam; particle-in-cell
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