The study of tidal circulation has a long history . The numerical simulation of tidal flow has been developed greatly with the development of computer techniques in the past two decades. The generalized wave equation ...The study of tidal circulation has a long history . The numerical simulation of tidal flow has been developed greatly with the development of computer techniques in the past two decades. The generalized wave equation finite-element method is a relatively new numerical model for studying shallow water flow . This method was used to simulate tidal waves of the Gulf of St. Lawrence in Canada . The very good agreement of the numerical results with the field data indicated that the model is an effective and promising numerical method for solving two-dimensional tidal wave problems .展开更多
为了实现波浪能的采集与高效转换,加快波浪能开发利用,提出一种新型双盘磁齿整流发电机(double disk magnetic tooth rectifier generator,DDMTRG)。首先,介绍发电机的结构特点和整流原理,结合盘式转子和磁齿轮工作特点分析其结构参数;...为了实现波浪能的采集与高效转换,加快波浪能开发利用,提出一种新型双盘磁齿整流发电机(double disk magnetic tooth rectifier generator,DDMTRG)。首先,介绍发电机的结构特点和整流原理,结合盘式转子和磁齿轮工作特点分析其结构参数;其次,采用气隙比磁导法及有限元仿真分析该发电机的空载电磁特性和负载输出特性;第三,基于矩角特性分析磁齿轮的带载能力,由外定子各典型位置磁密特征解析该发电机铜耗和铁耗;最后,讨论外定子、盘式转子和磁齿轮结构参数对该发电机运行特性的影响规律。研究结果表明:该电机可将浮子的上下浮动转换为发电机单一方向的旋转运动,实现了波浪运动的整流,效率在94%左右,能量利用率较高;空载气隙磁密和电动势波形正弦性较优,计算结果基本吻合;磁齿轮结构参数对该发电机运行特性影响较大,当盘式转子外圆周永磁体极弧系数为0.6,厚度为4.5 mm,气隙长度为0.5 mm,轴向长度为100 mm,磁齿轮半径为35 mm,长度为40 mm,磁齿轮外圆周永磁体厚度为4 mm,极弧系数为0.8时,双盘磁齿整流发电机的性能较优,发电效率较高,磁齿轮带载能力较强。展开更多
Numerical solution of time-lapse seismic monitoring problems can be challenging due to the presence of finely layered reservoirs.Repetitive wave modeling using fine layered meshes also adds more computational cost.Con...Numerical solution of time-lapse seismic monitoring problems can be challenging due to the presence of finely layered reservoirs.Repetitive wave modeling using fine layered meshes also adds more computational cost.Conventional approaches such as finite difference and finite element methods may be prohibitively expensive if the whole domain is discretized with the cells corresponding to the grid in the reservoir subdomain.A common approach in this case is to use homogenization techniques to upscale properties of subsurface media and assign the background properties to coarser grid;however,inappropriate application of upscaling might result in a distortion of the model,which hinders accurate monitoring of the fluid change in subsurface.In this work,we instead investigate capabilities of a multiscale method that can deal with fine scale heterogeneities of the reservoir layer and more coarsely meshed rock properties in the surrounding domains in the same fashion.To address the 3-D wave problems,we also demonstrate how the multiscale wave modeling technique can detect the changes caused by fluid movement while the hydrocarbon production activity proceeds.展开更多
横向磁通永磁电机以电负荷和磁负荷在空间上相互解耦,能获得较高的功率密度而闻名。因其同时具有低速、大转矩及多极数的优点而适用于直驱风力发电系统。与传统横向磁通永磁发电机相比,该文提出的新型双C型定子聚磁式转子的横向磁通永...横向磁通永磁电机以电负荷和磁负荷在空间上相互解耦,能获得较高的功率密度而闻名。因其同时具有低速、大转矩及多极数的优点而适用于直驱风力发电系统。与传统横向磁通永磁发电机相比,该文提出的新型双C型定子聚磁式转子的横向磁通永磁发电机空间利用率得到明显提高。对发电机的基本结构和运行原理作了详细的描述。为了验证双C型结构在原理上的可行性,采用三维有限元分析计算了空载磁场分布,对其静态特性和瞬态特性包括磁通密度、电枢反电势,以及电枢自感波形进行了研究,对发电机的齿槽转矩也进行了分析。结果表明,双C型定子结构可以显著提高横向磁通永磁发电机的功率密度。最后设计研制了一台三相1 k W样机,并进行了实验,实验结果与理论分析基本一致。展开更多
文摘The study of tidal circulation has a long history . The numerical simulation of tidal flow has been developed greatly with the development of computer techniques in the past two decades. The generalized wave equation finite-element method is a relatively new numerical model for studying shallow water flow . This method was used to simulate tidal waves of the Gulf of St. Lawrence in Canada . The very good agreement of the numerical results with the field data indicated that the model is an effective and promising numerical method for solving two-dimensional tidal wave problems .
基金support of Mega-grant of the Russian Federation Government(N 14.Y26.31.0013)。
文摘Numerical solution of time-lapse seismic monitoring problems can be challenging due to the presence of finely layered reservoirs.Repetitive wave modeling using fine layered meshes also adds more computational cost.Conventional approaches such as finite difference and finite element methods may be prohibitively expensive if the whole domain is discretized with the cells corresponding to the grid in the reservoir subdomain.A common approach in this case is to use homogenization techniques to upscale properties of subsurface media and assign the background properties to coarser grid;however,inappropriate application of upscaling might result in a distortion of the model,which hinders accurate monitoring of the fluid change in subsurface.In this work,we instead investigate capabilities of a multiscale method that can deal with fine scale heterogeneities of the reservoir layer and more coarsely meshed rock properties in the surrounding domains in the same fashion.To address the 3-D wave problems,we also demonstrate how the multiscale wave modeling technique can detect the changes caused by fluid movement while the hydrocarbon production activity proceeds.
文摘横向磁通永磁电机以电负荷和磁负荷在空间上相互解耦,能获得较高的功率密度而闻名。因其同时具有低速、大转矩及多极数的优点而适用于直驱风力发电系统。与传统横向磁通永磁发电机相比,该文提出的新型双C型定子聚磁式转子的横向磁通永磁发电机空间利用率得到明显提高。对发电机的基本结构和运行原理作了详细的描述。为了验证双C型结构在原理上的可行性,采用三维有限元分析计算了空载磁场分布,对其静态特性和瞬态特性包括磁通密度、电枢反电势,以及电枢自感波形进行了研究,对发电机的齿槽转矩也进行了分析。结果表明,双C型定子结构可以显著提高横向磁通永磁发电机的功率密度。最后设计研制了一台三相1 k W样机,并进行了实验,实验结果与理论分析基本一致。
基金Supported by the National Natural Science Foundation of China(50976072,51106099,10902070)the Leading Academic Discipline Project of Shanghai Municipal Education Commission(J50501)the Science Foundation for the Excellent Youth Scholar of Higher Education of Shanghai(slg09003)~~
