Uncertainty analysis of flow rate measurement for multiphase flow using CFD

The venturi meter has an advantage in its use,because it can measure flow without being much affected by the type of the measured fluid or flow conditions.Hence,it has excellent versatility and is being widely applied in many industries.The flow of a liquid containing air is a representative example of a multiphase flow and exhibits complex flow characteristics.In particular,the greater the gas volume fraction（GVF）,the more inhomogeneous the flow becomes.As a result,using a venturi meter to measure the rate of a flow that has a high GVF generates an error.In this study,the cause of the error occurred in measuring the flow rate for the multiphase flow when using the venturi meter for analysis by CFD.To ensure the reliability of this study,the accuracy of the multiphase flow models for numerical analysis was verified through comparison between the calculated results of numerical analysis and the experimental data.As a result,the Grace model,which is a multiphase flow model established by an experiment with water and air,was confirmed to have the highest reliability.Finally,the characteristics of the internal flow Held about the multiphase flow analysis result generated by applying the Grace model were analyzed to find the cause of the uncertainty occurring when measuring the flow rate of the multiphase flow using the venturi meter.A phase separation phenomenon occurred due to a density difference of water and air inside the venturi,and flow inhomogeneity happened according to the flow velocity difference of each phase.It was confirmed that this flow inhomogeneity increased as the GVF increased due to the uncertainty of the flow measurement.

A Home Appliance Recognition System Using the Approach of Measuring Power Consumption and Power Factor on the Electrical Panel, Based on Energy Meter ICs

Currently a large effort is being done with the intention to educate people about how much energy each electrical appliance uses in their houses, since this knowledge is the fundamental basis of energy efficiency programs that can be managed by the household owners. This paper presents a simple yet functional non-intrusive method for electric power measurement that can be applied in energy efficiency programs, in order to provide a better knowledge of the energy consumption of the appliances in a home.

Pre-and post-selected measurements with coupling-strength-dependent modulation

Pre-and post-selected(PPS) measurement, especially the weak PPS measurement, has been proved to be a useful tool for measuring extremely tiny physical parameters. However, it is difficult to retain both the attainable highest measurement sensitivity and precision with the increase of the parameter to be measured. Here, a modulated PPS measurement scheme based on coupling-strength-dependent modulation is presented with the highest sensitivity and precision retained for an arbitrary coupling strength. This idea is demonstrated by comparing the modulated PPS measurement scheme with the standard PPS measurement scheme in the case of unbalanced input meter. By using the Fisher information metric, we derive the optimal pre-and post-selected states, as well as the optimal coupling-strength-dependent modulation without any restriction on the coupling strength. We also give the specific strategy of performing the modulated PPS measurement scheme, which may promote practical application of this scheme in precision metrology.

Development of laser and microwave scanning technologies in the blast furnace burden profile and lining condition measurement at CSC

In order to stabilise the operation of the blast furnace and to raise its operation efficiency,research works for the application of microwave and laser scanning technologies to the measurement have been intensively carried out at China Steel Corporation(CSC).To monitor the burden profile during the operation,a microwave burden profile measuring system was developed.The system consists of a radar unit,a signal processing system, and a driving device which is capable of rotating the radar to scan the burden surface in a specified direction.A nitrogen cooling system was designed to protect the measurement system.A prototype burden profile meter was successfully tested in No.1 blast furnace in 2008,and a permanent one was installed at No.3 blast furnace.The system has provided useful information for adjusting the charging sequence in No.3 blast furnace.For another application,3 - D laser scanning technology is employed to monitor the blast furnace lining condition.To this end,a data registration method has been developed,through which two measured range images sensed at different period and locations can be fitted into the same coordinate system.In practice,the erosion of the blast furnace lining can be estimated when the current inner profile is compared with that taken before the blow-in operation. This technology is also adopted to evaluate the performance of gunning operation in the blast furnaces at CSC.

TPS based on trilateration for the feed measurement of FAST

Five-hundred-meter Aperture Spherical radio Telescope( FAST) is the largest sensitive single dish radio telescope in the world,in which the control and measurement of the feed is one crucial section of the FAST control system. Trilateration is presented to obtain three-dimensional coordinate for tracking feed focus cabin. Every three total stations chase prism movement to be attached on feed focus cabin and the prism position is determined from the measured distances based on the principle of trilateration. Therefore,feed position is determined from three prisms on the focus cabin. This study is to assess the accuracy and reliability of trilateration calculation on tracking focus cabin of FAST. Different arrangement of total stations on trilateration is theoretically studied. Through experiment,the proposed method shows that the accuracy is better than that of the polar coordinate measurement. The average root mean square error is lower than 0. 6 mm,which is found to have high accuracy and reliability.

基于卡曼滤波的矿浆浓度计设计

设计了一种基于卡曼滤波的γ射线浓度计。通过分析射线浓度计的测量原理,建立了射线强度与矿浆浓度的关系式;利用卡曼滤波对射线强度进行最优估计,以抑制测量结果的扰动;最后通过最小二乘法分段拟合计算对应的浓度。结果表明,该浓度计测量及时、准确,最大误差0.328个百分点,均方根误差0.194个百分点,测量精度得到有效提高。

测汞仪自动化进样系统

采用自主研发的软件控制精密注射泵,并结合化学还原汞标准溶液方法,可解决目前台站监测设备测汞仪溯源困难的问题。对比分析了手动操作和自主设计自动化进样系统在测汞仪标校过程中的测试结果。通过线性曲线和重复性试验,表明自动化进样与手动操作测量都体现出极好的线性度和重复性。自动化装置和人工操作判定系数R2为0.997和0.996,重复性分别为1.8%和2.2%,表明了自动化装置测试结果比手动操作精度更高。自动化进样系统操作起来更简便、易实行,降低了工作人员的操作强度,不仅提高了工作效率,减少因操作时间过长造成的汞标准物质失效,还可避免汞源对人体的直接危害。

DCS控制器中电表接触传感器计量误差检测方法

由于DCS控制器中电表传感器在计量检测过程中,传统的B-MAC-DCS协议能耗和丢包率较高,无法缓解汇聚节点的漏斗效应,导致在远程抄表过程中传感器计量误差增大。提出一种机械电表接触传感器计量误差检测方法。采用小波基函数对DCS控制器中的接触传感器计量数据抗干扰处理,并通过动态选取阈值的方法,对经过小波变换后的数据去除噪声。使用低功耗自适应集簇分层型(low energy adaptive clustering hierarchy,LEACH)协议分簇代替传统的B-MAC协议;根据簇内监测值,引入阈值分析方法获取传感器计量指标,并将其作为判定依据进行误差检测,根据计量指标的变化情况判断是否存在计量误差。实验结果表明,所提方法可以准确且有效检测出机械电表接触传感器计量误差,解决DCS中机械电表的运行隐患问题。

孔板流量计取压方式的研究

孔板流量计是一种测量流体流量的差压类流量计,广泛应用于石油、化工、电力等领域。孔板流量计主要的取压方式为法兰取压、角接取压和径距取压,其取压方式是影响测量精度的重要因素之一,现如今没有一个选取取压方式的标准。该文通过实验的方式将孔板流量计分别采用法兰取压、角接取压、径距取压计算得到的流出系数与GB/T2624.2中给出的各种不同取压方式理论流出系数进行比较,由实验结果可知环室角接取压的测量精度最高。通过比较加工精度和现场环境等因素,给出了3种取压方式的适用条件。

U型科里奥利质量流量计温度影响特性分析

温度对用于液氢等低温流体流量测量的科里奥利质量流量计的影响不可忽略。基于卡氏第二定理,从能量角度出发建立了考虑温度影响的U型科里奥利质量流量计数学模型,并搭建了U型科里奥利质量流量计实验平台,通过实验数据对比验证了模型。在此基础上,考虑测量管固体物性参数对温度的依变,探究了温度对科里奥利质量流量计测量的影响规律,提出了一种包含弹性模量、泊松比和线膨胀系数的低温修正方法。经液氮数值仿真结果和液氦科里奥利质量流量计实验结果对比,发现对弹性模量、泊松比和线膨胀系数三者进行综合修正比恒定温度补偿系数修正的相对误差更小。成果有助于深入理解低温科氏流量计的测量特性。

多姿态安装对水表流量性能的影响

流量特性是衡量水表性能的主要指标之一,为探究多流束旋翼式水表在不同安装姿态下产生的流量误差,利用多姿态冷水水表检定装置进行了计量误差试验,得出了水表安装成流动方向为自上而下的垂直方向时,水表流量性能最差,在水表安装成流动轴线处于垂直和水平方向之间的一个中间角度与水表安装成流动方向为自下而上的垂直方向相比,水表流量性能较好,将水表水平安装时,性能最好的结论。在通过Fluent软件的动网格加6DOF方法做了水表的流场仿真,估算出在试验中不同安装姿态在3个流量点情况下的摩擦阻力矩,依据摩擦阻力矩得到仿真误差,与试验误差进行对比分析,证实这些摩擦阻力矩是符合预期且可靠的。

超声波燃气表在宽温度范围下的计量性能试验研究

超声波燃气表是利用超声波在流体中传播特性测得流体流量,是成为新一代主流的燃气流量计量产品,其中,燃气表的温度适应性是衡量计量性能的重要项目。该项目通过试验研究,分析了其在温度范围(-25~55)℃的示值误差的计量性能。结果表明:该燃气表在高温和低温环境下的计量性能虽存在一定程度的变差,但仍满足1.5级要求,且其换能器组件的技术水平仍有较大提升空间。

评估原油交接过程动态计量输差的成对t检验方法研究

原油交接计量过程中由于流量计的误差、动态变化的压力与温度等不确定性因素而产生计量输差,引起交接计量纠纷。采用成对样本t检验与流量计误差分析相结合的新方法,对原油交接过程的动态计量输差进行了评估,对动态计量过程中的来油流量与回油流量两者之间的输差数据进行了正态性检验和相关性性检验。结果表明,采油厂与轻烃厂原油交接数据相关性非常的明显,输差数据服从正态分布,采油厂与轻烃厂原油交接计量的生产数据满足成对t检验的要求。通过成对样本t检验对输差数据进行了量化评估,给出了动态计量输差的合理偏差范围,分析了动态计量过程来油流量与回油流量两者之间输差的合理性。对流量计置信区间的分析表明,来油流量置信区间与回油流量置信区间的相对位置只能定性地显示输差是否明显,不像成对t检验可以定量地给出计量允差。成对t检验能够计算得到计量允差这一新量化指标,可将成对样本t检验方法与流量计的误差分析相结合,用于评估原油交接过程的动态计量输差。

电能计量异常处理方案的研究与分析

电力作为人们日常生产和生活的主要能源之一,其计量的准确性和稳定性直接关系到多方的经济利益.为提高电能计量准确性,文章提出了一种基于改进孤立森林算法的电能计量异常检测方法,并将该方法与未改进的孤立森林算法进行了实验对比,实验证明,文章提出的方法在电能计量异常检测中有着更好的性能.

柴油机台架漏气量测量自动修正方法

柴油机在研发试验阶段都会通过活塞漏气量来评价活塞、活塞环和缸体的设计质量。通过研究AVL442活塞漏气仪测量机理,发现在台架漏气量的实际测量中,漏出气体的温度、压力与漏气仪测量的参考温度、压力有明显差别,会在一定程度上影响漏气量测量。为此提出一种漏气量测量自动修正方法,在漏出气体进入漏气仪前测量其温度和压力,并基于台架数据采集系统的Calculation、LAM模块配置漏气量修正计算,在漏气量采集过程中自动修正测量值,从而提高台架漏气量测量准确度,提升台架与测试设备的关联分析能力。

仪器仪表中计量检测技术分析

仪器仪表计量检测能够提升仪器仪表精准度,发挥其最佳性能。本文首先分析了仪器仪表计量检测内容及要求,阐明了做好仪器仪表计量检测价值和意义,探讨了当前仪器仪表计量检测所处的现状及面临的问题,最后提出仪器仪表中计量检测技术应用对策,对指导仪器仪表计量检测实践具有积极的参考意义。

浅析原油计量交接提升改造系统应用现状

原油的交接计量是采油厂生产管理的一项基础工作,它在采油厂开发、生产、经营、管理过程中占有十分重要的地位。随着计量技术信息化、数字化、智能化的发展,孤东油气集输管理中心对内部原油交接点开展计量技术改造升级,逐步由“体积流量计+实验室化验”向“质量流量计+在线含水仪”转变,以信息化、自动化手段取代原油交接日常人工化验,提高数据准确率,实现贸易交接计量工作水平的整体提升。

分体式导波雷达液位计测量组件抗震方法研究

通过对某型号分体式导波雷达液位计测量组件结构的数学模型进行模态分析、静力分析和反应谱分析,得到了测量组件在各载荷工况下的位移和应力结果,并对螺栓的拉伸应力和剪切应力进行了校核。计算结果表明,测量组件结构满足规范和技术要求。

一次计量倍率错误引起的电量异常分析及防范措施

结合10 kV高供低计用户,装表接电人员工作失误,导致电流互感器a相极性反接,3只电流互感器穿芯匝数由2匝穿为1匝,出现错误接线与计量倍率的复合型计量故障,引起该用户电量异常,分析故障处理前后采集系统曲线数据的变化规律,结合误差理论,运用更正系数法与相对误差法,分别计算两个阶段的退补电量,提出详细防范措施,有效防范各种风险。

基于小波去噪和时频分析的智能电表量测数据挖掘研究

为提升智能电表量测数据挖掘效果,该文研究一种基于小波去噪和时频分析的智能电表量测数据挖掘方法。应用小波变换阈值去噪方法对数据集进行去噪,通过惩罚策略选择阈值后,对存在噪声的数据集进行运算,获取去噪后的数据集,根据去噪后的小波系数与存在噪声的小波系数获取最优阈值函数;利用自适应最优径向高斯核时频分析方法,有效将最优阈值函数的数据集分离为自分量信号与互分量信号,精准挖掘智能电表仿真模型数据库内数据,完成智能电表量测数据信息的输出。实验结果表明,所研究方法去噪效果较好,相对误差保持在2%以内,挖掘精度维持在96%以上,应用性能较好。