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  • Open Access

    ARTICLE

    Influence of Flap Parameters on the Aerodynamic Performance of a Wind-Turbine Airfoil

    Yuanjun Dai1,2, Jingan Cui1, Baohua Li1,*, Cong Wang1, Kunju Shi1

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.4, pp. 771-786, 2024, DOI:10.32604/fdmp.2023.029584

    Abstract A numerical method has been used to analyze the flow field related to a NACA 0015 airfoil with and without a flap and assess the influence of the flap height and angle on the surface pressure coefficient, lift coefficient, and drag coefficient. The numerical results demonstrate that the flap can effectively improve the lift coefficient of the airfoil; however, at small attack angles, its influence is significantly reduced. When the angle of attack exceeds the critical stall angle and the flap height is 1.5% of the chord length, the influence of the flap becomes very evident. As the flap height… More >

  • Open Access

    ARTICLE

    Research on Carbon Emission for Preventive Maintenance of Wind Turbine Gearbox Based on Stochastic Differential Equation

    Hongsheng Su, Lixia Dong*, Xiaoying Yu, Kai Liu

    Energy Engineering, Vol.121, No.4, pp. 973-986, 2024, DOI:10.32604/ee.2023.043497

    Abstract Time based maintenance (TBM) and condition based maintenance (CBM) are widely applied in many large wind farms to optimize the maintenance issues of wind turbine gearboxes, however, these maintenance strategies do not take into account environmental benefits during full life cycle such as carbon emissions issues. Hence, this article proposes a carbon emissions computing model for preventive maintenance activities of wind turbine gearboxes to solve the issue. Based on the change of the gearbox state during operation and the influence of external random factors on the gearbox state, a stochastic differential equation model (SDE) and corresponding carbon emission model are… More > Graphic Abstract

    Research on Carbon Emission for Preventive Maintenance of Wind Turbine Gearbox Based on Stochastic Differential Equation

  • Open Access

    ARTICLE

    TURBINE BLADE FILM COOLING USING PSP TECHNIQUE

    Je-Chin Han*, Akhilesh P. Rallabandi

    Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-21, 2010, DOI:10.5098/hmt.v1.1.3001

    Abstract Film cooling is widely used to protect modern gas turbine blades and vanes from the ever increasing inlet temperatures. Film cooling involves a very complex turbulent flow-field, the characterization of which is necessary for reliable and economical design. Several experimental studies have focused on gas turbine blade, vane and end-wall film cooling over the past few decades. Measurements of heat transfer coefficients, film cooling effectiveness values and heat flux ratios using several different experimental methods have been reported. The emphasis of this current review is on the Pressure Sensitive Paint (PSP) mass transfer analogy to determine the film cooling effectiveness.… More >

  • Open Access

    ARTICLE

    NUMERICAL INVESTIGATION OF FILM COOLING WITH CHEMICAL HEAT SINK

    Keyong Chenga,b,*, Chunzi Zhangc, Wei Chena,b, Shiqiang Lianga,†, Yongxian Guoa,d, Xiulan Huaia

    Frontiers in Heat and Mass Transfer, Vol.3, No.3, pp. 1-6, 2012, DOI:10.5098/hmt.v3.3.3003

    Abstract A film cooling method with chemical heat sink for gas turbine blades is proposed. In this method, an endothermic reaction of cooling stream occurs due to the heating from the mainstream, which leads to an improvement of film cooling effectiveness. The proposed method at different blowing ratios are computed and compared with the conventional one. The simulation result shows that due to the exsitence of the chemical heat sink the proposed method can enhance film cooling effectiveness not only in the streamwise direction, but also in the spanwise direction. More >

  • Open Access

    ARTICLE

    Computational Verification of Low-Frequency Broadband Noise from Wind Turbine Blades Using Semi-Empirical Methods

    Vasishta Bhargava Nukala*, Chinmaya Prasad Padhy

    Sound & Vibration, Vol.58, pp. 133-150, 2024, DOI:10.32604/sv.2024.047762

    Abstract A significant aerodynamic noise from wind turbines arises when the rotating blades interact with turbulent flows. Though the trailing edge of the blade is an important source of noise at high frequencies, the present work deals with the influence of turbulence distortion on leading edge noise from wind turbine blades which becomes significant in low-frequency regions. Four quasi-empirical methods are studied to verify the accuracy of turbulent inflow noise predicted at low frequencies for a 2 MW horizontal axis wind turbine. Results have shown that all methods exhibited a downward linear trend in noise spectra for a given mean wind… More >

  • Open Access

    ARTICLE

    Numerical Study of the Effect of Splitter Blades on the Flow-Induced Noise of Hydraulic Turbine

    Fengxia Shi1,2, Guangbiao Zhao1,*, Yucai Tang1, Haonan Zhan1, Pengcheng Wang1

    Sound & Vibration, Vol.58, pp. 101-117, 2024, DOI:10.32604/sv.2024.047082

    Abstract In order to study the effect of splitter blades on the internal and external sound field of the hydraulic turbine, the paper chose a centrifugal pump with a specific speed ns = 33 reversed as a hydraulic turbine as the research object, and added the short blades on the original impeller to form a new splitter impeller. Based on the Re-Normalization Group (RNG) k-ε turbulence model to conduct numerical simulation for the hydraulic turbine, this thesis calculated the internal and external acoustic field by means of the acoustic boundary element (BEM) and finite element (FEM) and analyzed the noise radiation… More >

  • Open Access

    ARTICLE

    Nonlinear Flap-Wise Vibration Characteristics of Wind Turbine Blades Based on Multi-Scale Analysis Method

    Qifa Lang, Yuqiao Zheng*, Tiancai Cui, Chenglong Shi, Heyu Zhang

    Energy Engineering, Vol.121, No.2, pp. 483-498, 2024, DOI:10.32604/ee.2023.042437

    Abstract This work presents a novel approach to achieve nonlinear vibration response based on the Hamilton principle. We chose the 5-MW reference wind turbine which was established by the National Renewable Energy Laboratory (NREL), to research the effects of the nonlinear flap-wise vibration characteristics. The turbine wheel is simplified by treating the blade of a wind turbine as an Euler-Bernoulli beam, and the nonlinear flap-wise vibration characteristics of the wind turbine blades are discussed based on the simplification first. Then, the blade’s large-deflection flap-wise vibration governing equation is established by considering the nonlinear term involving the centrifugal force. Lastly, it is… More >

  • Open Access

    ARTICLE

    Ice-Induced Vibrational Response of Single-Pile Offshore Wind-Turbine Foundations

    Zhoujie Zhu1, Gang Wang1, Qingquan Liu1, Guojun Wang2, Rui Dong2, Dayong Zhang2,3,*

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.3, pp. 625-639, 2024, DOI:10.32604/fdmp.2023.042128

    Abstract Important challenges must be addressed to make wind turbines sustainable renewable energy sources. A typical problem concerns the design of the foundation. If the pile diameter is larger than that of the jacket platform, traditional mechanical models cannot be used. In this study, relying on the seabed soil data of an offshore wind farm, the m-method and the equivalent embedded method are used to address the single-pile wind turbine foundation problem for different pile diameters. An approach to determine the equivalent pile length is also proposed accordingly. The results provide evidence for the effectiveness and reliability of the model based… More >

  • Open Access

    ARTICLE

    Influence of Trailing-Edge Wear on the Vibrational Behavior of Wind Turbine Blades

    Yuanjun Dai1,2,*, Xin Wei1, Baohua Li1, Cong Wang1, Kunju Shi1

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 337-348, 2024, DOI:10.32604/fdmp.2023.042434

    Abstract To study the impact of the trailing-edge wear on the vibrational behavior of wind-turbine blades, unworn blades and trailing-edge worn blades have been assessed through relevant modal tests. According to these experiments, the natural frequencies of trailing-edge worn blades −1, −2, and −3 increase the most in the second to fourth order, the fifth order increases in the middle, and the first order increases the least. The damping ratio data indicate that, in general, the first five-order damping ratios of trailing-edge worn blades −1 and trailing-edge worn blades −2 are reduced, and the first five-order damping ratios of trailing-edge worn… More >

  • Open Access

    ARTICLE

    Study on Rotational Effects of Modern Turbine Blade on Coolant Injecting Nozzle Position with Film Cooling and Vortex Composite Performance

    Jiefeng Wang1, Eddie Yin Kwee Ng2,*, Jianwu Li1, Yanhao Cao1, Yanan Huang1, Liang Li1,2,3,*

    Frontiers in Heat and Mass Transfer, Vol.21, pp. 1-31, 2023, DOI:10.32604/fhmt.2023.045510

    Abstract The flow structure of the vortex cooling is asymmetrical compared to the traditional gas turbine leading edge cooling, such as the impingement cooling and the axial flow cooling. This asymmetrical property will affect the cooling performance in the blade leading edge, whereas such effects are not found in most of the studies on vortex cooling due to the neglect of the mainstream flow in the airfoil channel. This study involves the mainstream flow field and the rotational effects based on the profile of the GE E3 blade to reveal the mechanism of the asymmetrical flow structure effects. The nozzle position… More > Graphic Abstract

    Study on Rotational Effects of Modern Turbine Blade on Coolant Injecting Nozzle Position with Film Cooling and Vortex Composite Performance

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