分层注水工艺中涡街流量计信号处理方法研究

在一体化分层注水工艺中,每个层段的流量都要精确测量,而其所需的流量计必须能长期置于井下,综合考虑选择涡街流量计作为智能分层注水工艺中的流量检测装置.但涡街流量计易于受到管道震动和流场扰动引起的噪声干扰,且注水管道在注水的过程中更容易产生干扰信号,尤其在小流量处很难分辨出传感器产生的频率信号.本文根据涡街流量计的特点,提出一种以硬件和Mallat算法相结合,处理低频段无法分辨的问题,并进行了试验验证和现场应用.实验结果表明,使用该种方法,能有效的减少噪声干扰,降低了流量计的下限,提高了精度.     

Inertial Microfluidics with Integrated Vortex Generators Using Liquid Metal Droplets as Fugitive Ink

This work demonstrates a simple method for fabricating nearly spherical dome structures on top of lithographically defined microfluidic channels using gallium‐based liquid metal droplets as fugitive ink. The droplets remain stable during the pouring and curing of polydimethylsiloxane and can be easily removed by applying a basic solution. This facilitates the formation of domes with diameters of a few hundred micrometers patterned on the desired locations of the channel. The expansion of the channel at the interface of the dome leads to formation of a large vortex inside the dome. Experiments using high‐speed imaging along with numerical simulations show the utility of the vortex‐induced flow rotation for orbiting of human monocytes and polystyrene microbeads inside the dome. The lateral displacement of liquids caused by the vortex is further utilized for creating controllable multiband flow/color profiles within a T‐mixer. The method enables the fabrication of customized, complex, and 3D microfluidic systems utilizing planar microfabricated structures.     

Targeted Single‐Cell Therapeutics with Magnetic Tubular Micromotor by One‐Step Exposure of Structured Femtosecond Optical Vortices

Selective manipulation of specific single cells for therapeutics is important and highly desirable in biomedical research. As a simple and maneuverable tool, tubular micromotors have displayed appealing applications in encapsulation and transportation of cells. However, so far there are no reports on the simultaneous transportation of target single cells and the drugs with microtubes in a custom arrayed environment for targeted therapeutics. Moreover, fabrication of microtubes with 3D features in a reproducible and single‐step fashion, while, endowing them with the ability of remote control, remains challenging. In this study, a novel method for one‐step fabrication of magnetic 3D tubular micromotors by single exposure of structured optical vortices in a magnetic photoresist is presented. The size and geometry of fabricated microtubes are flexibly controlled in three dimensions. Precise propelling of the tubular micromotors and precise capture, targeted delivery, and release of SiO₂ microparticles are realized. Finally, as a proof‐of‐concept demonstration, in situ observation of the development of doxorubicin in Hela cells for therapeutic study is performed by targeted delivery of single cells and drug particles. The technology is simple and stable, which has promising applications in targeted cell therapy, drug screening, single cell studies, and other biomedical areas.     

泵站进水口淹没深度对漩涡的影响

泵站流道进水口漩涡会危害水泵运行,降低水泵性能。进水口漩涡的发生发展情况与进水口淹没深度有关,结合泵站实际运行情况选取5种不同的淹没深度,通过数值模拟,分析不同淹没深度下流道进水口的流场结构、漩涡的涡量变化及分布规律。研究结果表明:在流量不变,淹没深度0.09 D～0.2 D时,随着淹没深度的增大,漩涡强度变小。淹没深度为0.09 D的漩涡强度最大,在淹没深度为0和0.05 D的状况下没有明显漩涡产生。淹没深度为0.09 D、0.14 D、0.2 D时,漩涡均在距离进水流道进水口顶板以下0.3m附近终止。研究结果可为泵站设计进水口淹没深度参数提供一定参考。     

涡街提频振荡水柱驱动压电发电理论分析

海洋波浪能频率低(0.3～1 Hz),海浪进入振荡水柱气室压缩空气形成高速气流。在高速气流通道内放置绕流圆柱钝体,采用卡门涡街效应提高波浪能振荡水柱采集气室气压激振频率,实现高频驱动压电发电,提高海洋能量转换效率。推导波浪进入气室形成振荡的水气动力转换理论,计算了气室初级压强和流速。分析了低频高压气流经钝体形成卡门涡街高频涡流激振提频过程,计算出气压作用于钹型压电发电结构输出的电量。研究气体流速、钝体等系统参数与输出能量的关系。计算结果表明,周期为0.65～1.1 s的海浪进入气室经提频作用于钹型压电发电结构,稳定输出电能可达70～80 mW,为新型波浪能采集技术提供了理论基础。     

双月形圆周阵列超表面生成涡旋光束的研究

涡旋光束作为一种近年来新兴的结构化光束,因 自身携带轨道角动量的特性,使其在光学微操控、 生物医学、光信息传输等领域有着极大的应用前景。在以往生成涡旋光束的报道中,通常存 在器件尺寸较 大、激发光为圆偏光以及波长单一等问题,本文提出了一种基于双月形金属银单元与二氧化 硅基底结合的 亚波长尺寸超构表面来实现涡旋光束的生成。此种结构尺寸微小,且可以在偏振方向任意的 线偏光入射下, 通过调节超表面的双月形金属单元的横向尺寸来实现多种波长的涡旋光束输出。     

核心网HSS与PCRF拜访地改造模式探讨

拜访地接入是解决省间漫游带宽瓶颈的有效方式。对从归属地接入改造为拜访地接入的关键技术进行探讨,通过特定签约信息综合判断对目标用户进行有效识别,降低漫游上网时延,提升用户感知。     

水泵水轮机增减负荷过程三维流动特性大涡模拟分析

采用大涡模拟(LES)对水泵水轮机增减负荷过渡过程进行三维非定常数值模拟,捕捉到了不同开度下叶道中多种涡系结构,展示了叶道涡涡量分布,分析了水轮机工况及水泵工况小流量运行区的流动结构变化特性,揭示了水流进口攻角与叶道涡涡系结构关系,对各类叶道涡不同形态进行了研究并提出了马蹄涡识别变量,并对比分析了水轮机工况及水泵工况涡结构变化特性。计算表明水泵水轮机的水力稳定性与机组运行工况改变时的流动结构特性密切相关,在增减负荷过渡过程中,叶道涡结构的尺度及分布范围均随时间发生较大变化,是影响流态发生巨变的主要因素。     

乌东德水电站左岸进水口边坡岩溶问题分析

乌东德水电站左岸地下电站进水口边坡下游侧与大坝及缆机平台边坡、坝肩边坡相接。在边坡开挖支护过程中揭露到溶洞(缝),导致锚索施工困难,从而引起了各方对溶洞(缝)、溶蚀洼地、强风化角砾岩等岩溶现象可能影响到边坡整体稳定性的担忧。通过研究,溶蚀洼地第四系堆积体外侧为巨厚的Ⅲ1～Ⅲ2级岩体,强风化角砾岩呈囊状发育,周围亦被巨厚的Ⅲ1～Ⅲ2级岩体阻隔,均不影响边坡的整体稳定;坡表与锚索孔揭露的溶洞(缝)未形成连通管道,且溶缝与边坡走向大角度相交,亦不影响边坡的整体稳定。相关成果对边坡岩溶研究方法和类似工程的工程处理措施具有借鉴意义。     

沙牌水电站进水塔震损模拟分析

以沙牌水电站进水塔为例,研究了进水塔塔身以及上部排架在地震过程中的动力响应和震损机理。采用动力时程分析法计算进水塔在汶川地震作用下的加速度、位移和应力响应,并通过塔顶排架立柱极限承载力验算分析排架立柱震损破坏的原因。计算结果表明:进水塔动态分布系数大于规范建议值,刚度较小的主轴方向地震响应较大,立柱两端出现明显的应力集中。进水塔启闭机排架的震损是地震作用下压(拉)弯剪共同作用导致的,且立柱根部发生破坏,与实际资料吻合。