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Study on the Rotor Design Method for a Small Propeller-Type Wind Turbine

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Journal of Thermal Science 2016年第4期25卷 355-362页

作者： Yasuyuki Nishi Yusuke Yamashita terumi inagaki Department of Mechanical Engineering Ibaraki University Graduate School of Science and Engineering Ibaraki University

Small propeller-type wind turbines have a low Reynolds number,limiting the number of usable airfoil materials.Thus,their design method is not sufBciently established,and their performance is often low.The ultimate goal of this research is to establish high-performance design guidelines and design methods for small propeller-type wind turbines.To that end,we designed two rotors:Rotor A,based on the rotor optimum design method from the blade element momentum theory,and Rotor B,in which the chord length of the tip is extended and the chord length distribution is linearized.We examined performance characteristics and flow fields of the two rotors through wind tunnel experiments and numerical analysis.Our results revealed that the maximum output tip speed ratio of Rotor B shifted lower than that of Rotor A,but the maximum output coefficient increased by approximately 38.7%.Rotors A and B experienced a large-scale separation on the hub side,which extended to the mean in Rotor A.This difference in separation had an impact on the significant decrease in Rotor A's output compared to the design value and the increase in Rotor B's output compared to Rotor A.

关键词：优化设计方法转子桨式螺旋最大输出功率风力机性能特点风力涡轮机

Study on an Undershot Cross-Flow Water Turbine

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Journal of Thermal Science 2014年第3期23卷 239-245页

作者： Yasuyuki Nishi terumi inagaki Yanrong Li Ryota Omiya Junichiro Fukutomi Department of Mechanical Engineering Ibaraki University 4-12-1 Nakanarusawa-choHitachi-shi Ibaraki 316-8511JAPAN Graduate School of Science and Engineering Ibaraki University 4-12-1 Nakanarusawa-choHitachi-shi Ibaraki316-8511JAPAN Institute of Technology and Science The University of Tokushima 2-1 Minamijosanjima-cho Tokushima-shiTokushima 770-8506 JAPAN

This study aims to develop a water turbine suitable for ultra-low heads in open channels, with the end goal being the effective utilization of unutilized hydroelectric energy in agricultural water channels. We performed tests by applying a cross-flow runner to an open channel as an undershot water turbine while attempting to simplify the structure and eliminate the casing. We experimentally investigated the flow fields and performance of water turbines in states where the flow rate was constant for the undershot cross-flow water turbine mentioned above. In addition, we compared existing undershot water turbines with our undershot cross-flow water turbine after attaching a bottom plate to the runner. From the results, we were able to clarify the following. Although the effective head for cross-flow runners with no bottom plate was lower than those found in existing runners equipped with a bottom plate, the power output is greater in the high rotational speed range because of the high turbine efficiency. Also, the runner with no bottom plate differed from runners that had a bottom plate in that no water was being wound up by the blades or retained between the blades, and the former received twice the flow due to the flow-through effect. As a result, the turbine efficiency was greater for runners with no bottom plate in the full rotational speed range compared with that found in runners that had a bottom plate.

关键词：水轮机横流式有效利用率涡轮机农业用水水电能源功率输出底板

Unsteady Flow Analysis of an Axial Flow Hydraulic Turbine with Collection Devices Comprising a Different Number of Blades

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Journal of Thermal Science 2015年第3期24卷 239-245页

作者： Yasuyuki Nishi terumi inagaki Yanrong Li Sou Hirama Norio Kikuchi Department of Mechanical Engineering Ibaraki University 4-12-1 Nakanarusawa-cho Hitachi-shi Ibaraki 316-8511 JAPAN Graduate School of Science and Engineering Ibaraki University 4-12-1 Nakanarusawa-cho Hitachi-shi Ibaraki 316-8511 JAPAN Ibasei Ltd. 4-7-10 Kamine-cho Hitachi-shi Ibaraki 317-0064 JAPAN

We previously devised a new type of portable hydraulic turbine that uses the kinetic energy of an open-channel flow to improve output power by catching and accelerating the flow. The turbine contains an axial flow runner with an appended collection device and a diffuser section that is not axisymmetric. The objective of this study is to determine how interference between the collection device and the runner influences performance characteristics of the turbine. We investigated the performance characteristics of the turbine and flow field for different numbers of blades during both unsteady and steady flow. During an unsteady flow, the maximum values of power coefficients for three and two blades increased by approximately 8.8% and 21.4%, respectively, compared to those during a steady flow. For the three-blade runner, the power coefficient showed small fluctuations, but for the two-blade runner, the power coefficient showed large fluctuations. These fluctuations in the power coefficient are attributed to fluctuations in the loading coefficient, which were generated by interference between the runner and the diffuser section of the collection device.

关键词：轴流式水轮机收集装置非定常流同数刀片功率系数稳定流动高输出功率

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小型反馈射流振动器的动态特性研究

机械科学与技术 2016年第12期35卷 1894-1899页

作者：吴凛李艳荣稲垣照美湛从昌陈奎生武汉科技大学机械自动化学院武汉430081 茨城大学工学部

针对小型反馈射流振动器在低雷诺数下的流场的动态特性，利用粒子图形测速法（PIV）对其进行了二维测量实验，得到了不同流量下内部流场在振动稳定状态时的速度分布，流量范围为100～300ml/min。通过实验监测上下反馈通道出口处的Y方向... 详细信息

针对小型反馈射流振动器在低雷诺数下的流场的动态特性，利用粒子图形测速法（PIV）对其进行了二维测量实验，得到了不同流量下内部流场在振动稳定状态时的速度分布，流量范围为100～300ml/min。通过实验监测上下反馈通道出口处的Y方向分速度并分析射流的振动过程和原理。数据分析方法包括快速傅里叶变换和小波变换，得到不同流量时的振动频率，进而得出振动频率特性和斯特罗哈数特性。结果表明：该小型反馈射流振动器内部流场呈周期振动，快速傅里叶变换和小波变换得到的振动频率接近，频率特性和斯特罗哈数特性均为非线性。

关键词：粒子图像测速法（PIV）小型反馈射流振动器快速傅里叶变换小波变换