智能气体涡轮流量计的创新结构设计

我国天然气资源丰富,气体涡轮流量计一直是作为天燃气贸易计量的首选。本文论述气体涡轮流量计的机械结构上的几点优化设计,优化了气体涡轮流量计的曲线,提高了气体涡轮流量计的可靠性。     

口吹法初判气体涡轮流量计的小流量误差

针对当前气体涡轮流量计在生产及维修服务的标定效率低的问题,提出了一种口吹法,初步判别气体涡轮流量计的小流量误差,以避免对明显不合格产品做无效的标定,并通过分析气体涡轮流量计的计量性能特点和结合样机试验结果,进一步阐明该方法的实用性和高效性。     

气体涡轮流量计结构型式分析

通过对机械表头和电子表头两种结构型式的气体涡轮流量计的结构、工作原理、实际应用几方面所进行的分析比较,增加燃气计量用户对气体涡轮流量计产品的了解程度,便于在选型时做出正确的选择.     

叶片螺旋角对气体涡轮流量计性能影响的分析

在分析气体涡轮流量计结构和数学模型的基础上,针对涡轮叶片螺旋升角对仪表性能的影响,以安装35°、45°和55°三种不同叶片螺旋升角涡轮的DN150型气体涡轮流量计作为实验对象,搭建仪表负压检测平台,分别对仪表系数、压力损失和计量精度进行实验检定与对比分析。实验结果表明,合理设计涡轮叶片螺旋升角能显著改善气体涡轮流量计的性能,为叶片螺旋升角进一步优化及其对仪表性能影响规律的研究提供了实验基础。     

气体流量计量新标准——音速喷咀

本文简要介绍一种应用音速喷咀的新型气体流量计量标准的基本原理,着重分析了音速喷咀试验设备和音速喷咀流出系数的误差。通过对八套音速喷咀的标定,其极限误差在±0.2%以内。并应用音速喷咀对涡轮流量计、腰轮流量计和密度补偿式孔板气体质量流量计进行标定。涡轮流量计与腰轮流量计的线性度在±0.54%以内;密度补偿式孔板气体质量流量计的线性度在±1.2%以内。     

气体涡轮流量计中动压气体轴承的研究

气体涡轮流量计主轴承大多采用油润滑的滑动轴承或滚动轴承,存在较大的局限性。采用螺旋槽气体轴承,设计了一种气体涡轮流量计。按最大稳定性的原则,利用MATLAB软件,系统地分析了在气体涡轮流量计中动压气体轴承的结构形式对其载荷及稳定性的影响,得到了气体涡轮流量计中动压气体轴承的可行工作范围。     

气体涡轮流量计后导流体结构优化设计

通过数值模拟和实验测试相结合的方法,研究了LWQ80气体涡轮流量计后导流体的结构优化及其计量性能的变化规律。基于流量计内部流场特征及其流动机理的探究,分析得出造成后导流体压损的主要原因是后导流体区域的壁面边界层分离和流体流向偏转。由此提出了缩小分离区和提升导流片导流效果的优化思路,通过延长后导流体的长度和延后导流片的位置,设计了一种改进型的后导流体结构。研究结果表明：后导流体结构经过改进后,气体涡轮流量计的计量性能得到了明显提升。在流量为250 m~3/h时流量计的压损降低了20.5%左右,仪表系数的恒定性显著提高,最大示值误差降低了近2.5倍,且能有效延长流量计的使用寿命。研究结果有助于为气体涡轮流量计的结构与性能优化提供理论指导和技术支持。     

气体涡轮流量计性能优化的模拟与实验研究

以TRZ80气体涡轮流量计为研究对象,采用数值模拟与实验测试相结合的方法,提出了前整流器和后导流体的结构优化方案。通过对结构优化前后流量内部流场特征的分析,揭示了流量计结构与性能优化背后确切的流体力学机制。研究结果表明：前整流器和后导流体区域的压降突变与后导流体尾部的涡旋结构和回流现象是影响流量计计量性能的主要机制。优化的流量计结构可以明显减弱压降突变、涡旋结构与回流现象。优化的流量计结构既可以显著降低流量计的压力损失,又可以明显提高流量计的测量精度与稳定性,其压力损失和线性度误差分别降低了约48.58%和32.43%。研究结果有助于为今后开发与量产计量性能更好的气体涡轮流量计提供理论指导和技术支持。     

气体涡轮流量计测量不确定度分析

本文阐述了气体涡轮流量计的工作原理,依据JJG1037-2008《涡轮流量计》检定规程和JJF1059-1999《测量不确定度评定与表示》要求,建立了气体涡轮流量计测量不确定度的数学模型,对影响测量不确定度的各个贡献量进行分析,最后得出气体涡轮流量计的不确定度分析报告。     

多声道气体超声流量计在城市煤气的应用

一概述 1．气体超声流量计进入市场的机遇 在我国以前常用孔板、罗茨（腰轮）、涡轮和膜盒式等气体流量计来测量城市燃气的流量,直到上世纪90年代中后期才掀起使用气体超声流量计（Gas UItrasonic Flowmeter,GUSF）热潮,成为继孔板、涡轮流量计之后的一类重要的天然气用流量计,在“西气东输”的干线中将气体超声流量计作为流量计量的首选仪表。     

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...     

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。     

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.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.