本文研究了基于空间向量拟合空间圆直接获取圆心坐标及半径的算法,将该算法应用于空间圆形物体的形态检测与分析。以Microsoft Visual Studio 2008为平台,运用C#编程语言开发了基于PDA的空间圆形物体形态检测与分析系统。以校内混流式...本文研究了基于空间向量拟合空间圆直接获取圆心坐标及半径的算法,将该算法应用于空间圆形物体的形态检测与分析。以Microsoft Visual Studio 2008为平台,运用C#编程语言开发了基于PDA的空间圆形物体形态检测与分析系统。以校内混流式水轮机转子实体模型作为研究对象,结合HP iPAQ移动设备进行实例计算与分析,表明利用该系统可进行水轮机转子空间形态的拟合,进行水轮机转子圆心坐标和半径的计算,完成水轮机转子空间形态的质量评价。研究成果也可为其它空间圆形物体的形态检测工作提供参考。展开更多
Flows through an open cross-flow-type nano-hydraulic turbine are numerically simulated to investigate the effects of the clearance Hc between the rotor and the ground on the turbine performance. A two-dimensional part...Flows through an open cross-flow-type nano-hydraulic turbine are numerically simulated to investigate the effects of the clearance Hc between the rotor and the ground on the turbine performance. A two-dimensional particle method is employed, which was successfully used for flow simulations of impulse-type and open cross-flow-type nano-hydraulic turbines in the authors＇ previous works. When the clearance Hc is smaller than a critical value, the simulated turbine performance decreases with decreasing Hc, in good agreement with the experiment. The simulations make it clear that such a reduction of turbine performance is attributable to an increase in the circumferential component of the water velocity at the rotor outlet. The simulations also demonstrate that the effect of the tip speed ratio of the rotor on the relation between Hc and turbine performance can be analyzed.展开更多
A new oscillating water column (OWC) design is proposed in this study to incorporate a simpler Savonius type turbine. Conventional OWC devices employ a bi-directional turbine such as a Wells or an Impulse turbine to e...A new oscillating water column (OWC) design is proposed in this study to incorporate a simpler Savonius type turbine. Conventional OWC devices employ a bi-directional turbine such as a Wells or an Impulse turbine to extract energy from the air. The disadvantages of the Wells turbine include its inability to self start and stalling. The Savonius turbine is much cheaper and is an effective option at low Reynolds numbers. In the current rectangular OWC device, unlike the circular OWC, the width of entry of the capture chamber can be increased without being influenced by the diameter at the turbine section. To improve its primary capture efficiency, the front and rear walls of the OWC are inclined to minimize reflection. The Savonius rotor characteristics are studied with respect to the change in frequency of the incoming waves. The rotor rpm is sensitive to wave period and primary conversion efficiency while changes in depth only affect the rotor rpm at lower frequencies. The Savonius rotor shows promising results and can be incorporated into large scale OWC devices to reduce costs of the turbine component of the system.展开更多
文摘本文研究了基于空间向量拟合空间圆直接获取圆心坐标及半径的算法,将该算法应用于空间圆形物体的形态检测与分析。以Microsoft Visual Studio 2008为平台,运用C#编程语言开发了基于PDA的空间圆形物体形态检测与分析系统。以校内混流式水轮机转子实体模型作为研究对象,结合HP iPAQ移动设备进行实例计算与分析,表明利用该系统可进行水轮机转子空间形态的拟合,进行水轮机转子圆心坐标和半径的计算,完成水轮机转子空间形态的质量评价。研究成果也可为其它空间圆形物体的形态检测工作提供参考。
文摘Flows through an open cross-flow-type nano-hydraulic turbine are numerically simulated to investigate the effects of the clearance Hc between the rotor and the ground on the turbine performance. A two-dimensional particle method is employed, which was successfully used for flow simulations of impulse-type and open cross-flow-type nano-hydraulic turbines in the authors＇ previous works. When the clearance Hc is smaller than a critical value, the simulated turbine performance decreases with decreasing Hc, in good agreement with the experiment. The simulations make it clear that such a reduction of turbine performance is attributable to an increase in the circumferential component of the water velocity at the rotor outlet. The simulations also demonstrate that the effect of the tip speed ratio of the rotor on the relation between Hc and turbine performance can be analyzed.
文摘A new oscillating water column (OWC) design is proposed in this study to incorporate a simpler Savonius type turbine. Conventional OWC devices employ a bi-directional turbine such as a Wells or an Impulse turbine to extract energy from the air. The disadvantages of the Wells turbine include its inability to self start and stalling. The Savonius turbine is much cheaper and is an effective option at low Reynolds numbers. In the current rectangular OWC device, unlike the circular OWC, the width of entry of the capture chamber can be increased without being influenced by the diameter at the turbine section. To improve its primary capture efficiency, the front and rear walls of the OWC are inclined to minimize reflection. The Savonius rotor characteristics are studied with respect to the change in frequency of the incoming waves. The rotor rpm is sensitive to wave period and primary conversion efficiency while changes in depth only affect the rotor rpm at lower frequencies. The Savonius rotor shows promising results and can be incorporated into large scale OWC devices to reduce costs of the turbine component of the system.
