一控三泵控泵注水泵站系统的应用

基于泵控泵（PCP）技术的一控三泵控泵注水泵站系统,综合应用摘段调节、变速调节和泵的串联改变注水系统的特性曲线,使大功率多级高压离心泵始终在高效区工作,实现注水泵输出压力和流量可调,能达到节能降耗的目的并实现多种工况组合备用。实际应用表明,该系统降低了泵管压差和注水电耗,提高了注水效率,有效地解决了油田注水电耗大的问题。     

螺旋流对环形射流泵性能影响的数值模拟

为了提高环形射流泵的输送效率,本文提出了一种利用导叶结构形成螺旋流的螺旋流环形射流泵。利用数值模拟的方法研究不同工作压力下的螺旋流环形射流泵和原型泵的速度、压力和湍动能分布计算结果,来分析螺旋流对环形射流泵的性能影响。数值模拟结果表明：在工作压力为130 kPa时,螺旋流使环形射流泵的流量比增加了43.1%,压力比降低了22.8%。螺旋流降低了环形射流泵喉管内的静压,更容易引起空化。螺旋流使得环形射流泵的效率在工作压力低于160 kPa时大于原型泵。螺旋流环形射流泵内具有更大的湍动能分布区域。随着工作压力升高,两种结构的环形射流泵湍动能分布差别减小。导叶阻力对螺旋流环形射流泵的效率有着重要的影响。     

单泵双喷嘴尿素喷射系统泵压控制策略研究

为满足国七排放法规要求,需要采用单泵双喷嘴尿素喷射系统。针对双喷射系统,现有的控制不能够满足喷射系统的喷射精度和响应性。本文设计了基于模型的尿素泵压力控制策略,首先根据尿素泵和喷嘴的工作原理构建基于流量压力的部件物理模型,并通过质量守恒方程建立尿素泵压力的微分方程,离散化后建立离散压力模型,然后设计基于逆模型的前馈控制和反馈控制策略,实现尿素泵压力控制。通过试验验证表明,在WHTC循环下基于模型的尿素喷射控制策略能够实现压力稳定控制,且循环偏差不超过5%。     

管式泵固定阀密封问题的研究

针对沁水蓝焰煤层气公司普通管式泵固定周密封不严导致泵效降低的问题,在大量调研及现场实验的基础上,通过在煤层气井排水口安装一种单流阀,使单流阀球阀的锁紧与打开从而改变柱塞上部液柱压力与泵内压力压差的原理阻止固定阀漏失、以提高泵效.在晋煤集团沁水蓝焰煤层气公司六口高煤粉井现场实验证明,该装置提高泵效的成功率达100％.     

润滑孔对超高速切线泵性能的影响北大核心CSCD

为了获得泵腔的润滑孔对泵的输出性能的影响规律,采用数值仿真结合试验验证的方法分析了润滑孔在泵腔周向、径向的不同位置分布以及不同孔径时泵的性能。结果表明:在周向,润滑孔处于泵喷射口朝向一侧的半周时对泵输出总压影响较小,处于另一侧半周时会降低泵输出总压,在180°时的泵输出总压比在45°时的输出总压提高了4.8%;在径向,靠中心位置的润滑流量比靠外缘的润滑流量降低了80%,出口输出总压则提高了2%;当润滑孔周向设在与喷射口距离较远位置附近时,适当增大润滑孔有助于提高泵输出压力,若周向设在距离喷射口较近的位置,则大的润滑孔会降低泵的输出压力。     

造纸冲浆泵中交流变频器的应用

冲浆泵广泛用于高速纸机封闭式供浆系统.介绍了基于造纸工艺的速度控制原理,通过增设压力变送器来实现PID控制的冲浆泵变频改造方法.实践证明,安装变频控制系统能适应不同车速、不同品种的用量变化,使冲浆泵的运行始终处于高效状态,大大稳定了工艺条件.使用变频器调速替代阀门调节浆流量,使冲浆泵的能耗降低,节能率在30%以上.     

PCP泵站改造技术在中原马寨注水站的应用

注水电耗占原油生产总电耗的首位,注水节能成为降低原油生产成本的关键.中原马寨注水站通过节流方式调节注水压力和流量,泵管压差大,泵效低,能量损失大.选取基于前置增压泵压力和流量可调控的泵控泵,Pump-Control-Pump,简称PCP,技术改造方案,使高压注水泵工作在高效区,节能效果明显.     

多功能泵再循环自动调节阀

介绍了电力行业热力凝结水及给水系统的泵出口压力控制系统、旁路控制系统及新开发的泵再循环自动调节系统，分析了多功能泵再循环自动调节阀在系统中的工作状态及结构特点。     

双斜盘轴配流轴向柱塞式液压电机泵的实验研究

研制了一种双斜盘轴配流轴向柱塞式液压电机泵样机，并通过实验研究了样机所能达到的性能：理论排量7 mL/r、额定工作转速6000 r/min下公称压力20 MPa; 5000 r/min下最大工作压力30 MPa;液压泵部分的容积效率达到91%以上。测得液压电机泵总效率最高值到达61%,中等转速区间(2000～4500 r/min)和压力区间(10～30 MPa)范围内总效率在0.56～0.61。实验表明，此类型液压电机泵，转子黏性阻力损失和配流轴间隙处的泄漏损失是两大主要损失，温度对这两大损失分别有明显的减少和增加作用，通过改善散热条件、选取合适的配流副间隙和使用低黏度液压油，有望更进一步提高样机的总效率。结果表明：适度提高液压电机泵的工作转速和提高电机的电流密度可以显著提高液压电机泵的功率密度，但转速过高，会带来较大的黏性阻力损失；采用较低工作转速、偏细长型的转子，采用低黏度液压油和取合适的配流副间隙，并且改善散热条件等，都是提高轴配流液压电机泵总效率的有效方法。     

基于BP神经网络的700型压裂泵优化设计

针对目前压裂泵泵效低、压力波动大,不能满足压裂工艺发展要求的现状,以提高泵效和降低压力波动为优化目标,通过BP神经网络的自学习建立起了压裂泵优化目标与设计变量之间的神经网络模型,并采用VB编程调用Matlab强大的神经网络算法库对BP神经网络模型进行了求解,得到了设计变量的优化值,实现了对700型压裂泵主要结构参数的优化设计.     

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.