原油容积式流量计示值误差测量结果的不确定度评定

正本文针对体积管校准原油容积式流量计的示值误差的测量结果,进行不确定度的分析及评定。一、评定对象、方法及技术依据1.技术依据:JJG667-2010《液体容积式流量计检定规程》。2.计量标准:体积管流量标准装置。3.被测对象:一台DN80mm的刮板流量计。4.测量方法:通过体积管对刮板流量计进行校准,对每个流量点重复测量3次,体积管的累积流量与流量计的累积流量进行对比,得出流量计的平     

科氏质量流量计测量含气液体流量关键技术综述

含气液体流量测量是科氏质量流量计面临的测量难题,对科氏质量流量计的驱动技术、信号处理技术都提出更高的要求。从驱动、信号处理、误差修正这3大核心技术出发对科氏质量流量计测量含气液体流量进行综述,分析含气液体流量下,驱动、信号处理以及误差修正技术的难点,并针对难点总结出含气液体流量下最佳的驱动技术、信号处理技术和误差修正技术。分析含气液体流量科氏质量流量计原始测量误差大的原因以及采用修正方法修正后的测量精度依旧无法达到单相流测量精度0.1级的原因,为提高科氏质量流量计测量含气液体流量的准确度提供参考。     

便携式超声波流量计在矿山主排水系统流量测试中的方法及常见问题综述

便携式超声波流量计采用非接触式测量方式,具有体积小、重量轻、携带方便、测量精度高、实时性强,可实现智能现场打印,保证流量数据完整等特点,这些特点非常适合生产现场的流量测量。本文结合矿山应用实际,论述了这种流量计的测试方法及其常见问题的产生原因及解决方法。     

基于涡街流量计的液氨测试技术

本文介绍了化工企业中使用涡街流量计来测量液氨流量的重要性,以及合理的流量计安装条件.在运行中主要出现的故障及维护方法.     

无节流元件蒸汽流量测量的一种可行方法

介绍了目前常用的蒸汽流量测量方法--直接测量法,对其测量原理、特点及测量误差进行了分析。针 对系统工况负荷变化频繁、蒸汽流量经常出现大幅度波动、直接测量流量误差较大的问题,提出了一种流量软测 量,即无节流元件的蒸汽测量方法。利用此方法对蒸汽流量进行计算,并与实际流量计测量值对比,得出在流量波动时,流量计测量误差为10%,而软测量误差最大不超过5%。     

一种蒸汽流量计量系统选型应用

目前世界上主流的蒸汽流量测量方法有节流式差压流量计和涡街流量计,这两种方法互有优缺点。除此以外,质量流量计、超声流量计在蒸汽流量测量中也有一些应用。涡街流量计和节流式差压流量计的主要优缺点如表1所示。     

节流式流量计流出系数准确性研究

本文在深入分析节流式流量计流出系数特性的基础上 ,提出了用动态流出系数提高流量测量精度的方法 ,对节流式流量计的具体应用 ,提高流量测量精度和范围度等具有指导意义     

全量程燃气流量计的创新与应用

当前市场上使用的流量计多数都有一个测量下限,下限以下是无法计量的.对于峰谷值差很大的燃气流量测量,一般流量计的计量范围很难满足计量需求,小流量多被漏计,产生计量误差,导致计量损失.智能式全量程燃气流量计利用两种计量原理,有效地解决了这一测量下限问题,实现了几乎从“零”计量.本流量计是集涡街及热式两种原理的流量计于一体的高度一体化仪表.由于采用了智能化处理,可直接显示出温度、压力和标准状态下的瞬时流量(m3/h)及累积流量(m3).     

迭代法在孔板流量计测量流量中的应用分析

应用实验室中ZKL智能孔板流量计测量质量流量和容积法水流量测量装置同时测量清水的记录数据和迭代法理论,分析并验证了孔板流量计测量质量流量,在一定的工作条件下,流出系数与雷诺数的函数关系式满足迭代法使用条件,给出了获得流量系数C值的处理方法.     

影响便携式超声流量计测量准确度的试验研究

便携式超声流量计可从管道外侧方便地测量流量,具有无压损,测量范围宽等特点,但流量计换能器的安装及参数设置直接影响测量结果的准确性.本文以美国GE公司的PT878型便携式超声流量计为例,通过实流试验开展了探头安装位置、管道周长、管道壁厚对超声流量计测量结果准确度的影响研究,并提出了便携式超声流量计安装过程中的注意事项,为保证流量测量的准确性提供了技术支持.     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。