电容式气固两相流的参数测量系统

为了实现气固两相流的多参数的测量和在线监测,设计并研发了一套基于直流充放电原理的气固两相流参数测量系统,其中主要包括与双螺旋式传感器相连接的2个电容检测通道的电容检测电路和实验平台,将双通道采集的电容数据通过相关算法的处理,获取截面固相速度,从而推算出气固两相流的固相质量流量,进而实现了气固两相流的多参数综合检测。将算得的质量流量与发料斗上的重力传感器获取的质量流量作对比,实验结果表明两者具有较好的一致性。     

基于双列阵电容传感器的气固两相流多参数测量系统

气固两相流体系是复杂的非线性动态系统,其流动过程的复杂性和随机性增加了气固两相流参数检测的难度。设计了一种基于双列阵电容传感器的硬件测量系统,该测量系统具有成本低、响应快、非侵入性和安全性好等优点,广泛应用在工业生产中。其采用Cortex-M4内核的STM32F407IGT6作为主控芯片进行微弱电容信号的采集,将采集的电容数据存储到SD卡且传送至上位机。将上位机接收的数据和SD卡中的数据进行离线分析和处理,得到固相浓度、速度和质量流量。实际使用结果表明,该测量系统测量精度较高、稳定性好,解决了传统测量仪表测量气固两相流时的弊端。     

电容式气固两相流浓度测量系统

本文介绍一种电容式气固两相流浓度测量系统,给出了具体的测量电极和测量电路。并采用所设计的电容式浓度测量系统在自行搭建的气力输粉系统上以面粉为媒质、在水平管道上对稀相气固两相流浓度进行了在线测量,获得了5×10^-5%体积百分比的面粉浓度分辨率。应用该系统对锅炉气力输粉管道中的气固两相流浓度进行实时在线检测与控制,对确保燃烧过程稳定,节能降耗和减少污染排放具有重大意义。     

基于双弯管法的稀相固相质量流量测量

双弯管法固相质量流量测量方法是以弯管流量计为基础,可实时测量气固两相流固相质量流量的方法。在前人研究的基础上对双弯管法固相质量流量测量模型进行了优化改进,建立了考虑气固两相流固相体积时的数学模型,并进行了实验研究,给出了基于新模型的固相质量流量计算公式。实验结果表明:新数学模型可以提高固相质量流量的测量精度,降低测量误差,与实际情况更加接近。     

基于双弯管法的稀相固相质量流量测量北大核心CSCD

双弯管法固相质量流量测量方法是以弯管流量计为基础,可实时测量气固两相流固相质量流量的方法。在前人研究的基础上对双弯管法固相质量流量测量模型进行了优化改进,建立了考虑气固两相流固相体积时的数学模型,并进行了实验研究,给出了基于新模型的固相质量流量计算公式。实验结果表明:新数学模型可以提高固相质量流量的测量精度,降低测量误差,与实际情况更加接近。     

基于融合传感器的气固两相流参数检测系统设计

为了快速实现气固两相流输送过程中的多参数检测,设计了一种基于双圆环静电传感器和螺旋式电容传感器融合传感器的参数测量系统。采用螺旋电极电容传感器测量管内固相相对浓度,以降低电容传感器灵敏场不均匀对浓度测量的影响。将双圆环静电传感器的信号作互相关运算获得固相速度。由固相流速与相对浓度最终计算出固相质量流量,从而实现气固两相流的流速、浓度、流量等参数的综合测量。将系统测量的质量流量与重力传感器检测的质量流量相对比,两者误差小于7%,具有较好的一致性。     

基于复合检测的气固两相质量测量系统的设计

介绍一种气固两相流固质量流量测量新技术,它利用传热学的原理,通过两点气体的流速测量,湿度测量和信息融合处理,可以实现固相质量流量的测量。     

气固两相流质量流量测量的新方法

文提出了一种采用电容传感器测量气固两相流质量流量的新方法。通过电容传感器对固相浓度的测量,可以求出气固两相流的固气比,结合气固混合之前所测得的载气流量,便可测出固相的质量流量。实测结果显示,测量误差小于5     

基于阵列式电容传感器的流速测量

为了解决气固两相流物体在管道中传输速度难以测量的问题,设计了一种基于阵列式电容式传感器系统的硬件和软件。硬件部分包括电容式阵列传感器的设计、流速测量电路、以太网通信模块和模数转换模块等。软件部分主要包括基于STM32F429最小系统的软件设计、电容数据采集转换程序以及以太网通信程序等。实际实验结果表明,测得流速数据的实际值相比于理论值误差在5%以内,该系统具有稳定性好,测量精度高,传感器设计简单等特点。     

工业气固两相流质量流量检测的研究

本文介绍了气固两相流量检测技术在工业生产中应用的意义及现状；基于相浓度＋速度原理的相关质量流量测量系统的原理；以及基于上述原理的电容式气固两相流流量计的工作原理及特点。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.