大管径水流量仪表性能分析

目前常用的大管径水流量测量仪表有节流差压流量计、电磁流量计、插入式涡轮流量计、插入式涡街流量计、均速管流量计以及超声波流量计等。本文试图对各种仪表在测量过程中的能量消耗、流速分布影响、安装直管段要求,对水质的要求等作些分布比较,供选用时参考。     

热式气体质量流量计预热特性的研究

针对热式气体质量流量计需要经过一定预热时间才能到达稳定的工作状态的问题,根据JJG897-1995《质量流量计》国家计量检定规程中关于示值误差计量的要求,设计气体质量流量计示值误差曲线与预热时间关系试验;并根据试验结果,提出热式气体质量流量计的合理预热时间。     

量热式质量流量计及其在氟化氢流量测量中的应用

介绍了一种量热式质量流量计的原理,并较详细地说明了用于氟化氢质量流量测量流量计的结构、测试与应用。该流量计可用于其它气体质量流量的测量。     

插入式超声波流量计在供水大口径管道中的应用

在供水系统计量中,工业流量测量普遍存在着大管径、大流量测量困难的问题,机械式水表使用较多,大管径流量的水表存在误差较大,计量不准,无校验手段。本文探讨在供水大口径管道中应用超声波流量计,并对该性能进行分析对比,提高供水计量的准确性。分别选用MF-G2和TDS-100型插入式超声波流量计,在现场应用,效果较好,精确度达到1%。     

热式气体流量计组分补偿方法研究

根据热式气体流量计的基本原理,混合气体的组分改变会导致流量计输出信号的变化,造成较大的测量误差.热式流量计需要重新送回厂家用专用设备进行重新标定.该问题严重影响了热式流量计的推广应用.基于换热方程分析以及经验公式,本文提出了一种新的组分补偿方法.该方法可分为两部分:离线的组分补偿和在线的流量计算.复杂的组分补偿计算可以通过主机上的补偿软件离线完成.流量计微计算机可以利用离线补偿结果完成在线的流量计算.实验结果验证了该组分补偿方法的有效性.     

恒电压式热式质量流量计的研究

本文介绍了热式质量流量计的测量原理及恒流式、恒温差式两种测量方法。根据热式流量计的测试原理。提出了用于小流量测量的恒电压式热式质量流量计的设计方案并进行了实验验证。实验表明在严格控制电压的条件下，流量计具有良好的性能。     

用于大管道中的烟气流量的计量

由于工况较差，烟气含尘量偏高，流速低、有腐蚀等诸多因素，给大管道烟气流量计的选型造成了一定的困难。而选用热式气体质量流量计可发挥其独特优点，作为大管道烟气流量测量手段的一种补充手段。     

GE气体超声流量计仪表系数不确定度的评定

超声流量计在工业生产检定校准中的应用越来越多,适用于管径比较大、不易拆装的气体流量计校准场合,那么对气体超声流量计本身的要求就越来越高。本文就检定超声流量计时对瞬时流量仪表系数的不确定度评定提出了一些方法以及影响的量。     

基于标记分子法的大管径气体流量的测量

介绍了一种基于标记分子法的新型电离式气体流量计.该流量计通过测量气体若干点的流速反映总体气体的流量.设计了微弱电流信号处理的硬件模拟电路;分析和计算了影响测量精度的硬件电路时间延迟;实现了在恶劣环境下大管径气体流量的准确测量.     

插入式流量计及其应用

插入式流量计种类很多,如电磁式、旋涡式、涡轮式、均速管式等等。插入式流量计压损小,节能效果显著,安装维护简单方便,投资回报快,可以在线拆装,尤其用于大管径测量,其优越性更为突出。近年来随着微处理技术的高速发展,仪表的精度和抗干扰能力完全能满足各种工业...     

Novel mass air flow meter for automobile industry based on thermal flow microsensor. II. Flow meter,test procedures and results

A prototype of mass air flow meter for automobile industry was developed on the basis of thermal flow microsensor. Design and manufacturing technology of the flow meter are described. Test procedure and results are presented. Developed prototype of flow meter can diagnose gas flow rates in a wide range.     

Theoretical and experimental investigation for developing a gas-liquid two-phase flow meter

Despite the intricacy, inline metering of two-phase flow has a significant impact in multitudinous applications including fusion reactors, oil, nuclear, and other cryogenic systems. Since measurement of individual flow rate is prominent in various systems, it warrants the establishment of a flow meter system that can monitor the mass flow rates of liquid. In this regard, an approach was taken towards the development of a two-phase flow meter system in the present study. The concept involves two-phase flow through narrow parallel rectangular channels resulting in laminar, stratified flow with a slope at the liquid-vapor interface. The height of the liquid column at specific channel locations is measured for determining the flow rate. However, the geometric configurations of the channels and fluid properties are pivotal in ensuring accurate measurement. Consequently, theoretical and experimental studies are performed to investigate the correspondence between flow rate and change in liquid height. Based on the governing equations, a theoretical model is established using MATLAB®. The model investigated the intricate influence of various flow and fluid properties in the estimation of the mass flow rate. The experimental investigation was done with various conditions under different liquid and vapor volume flow rates for validating the proposed supposition and the theoretical model. Both the theoretical and experimental analyses showed fair correspondence. The proposed system estimated the mass flow rate within a tolerance of ±10% and showed potential towards the development of the cryogenic two-phase flow meter.     

科里奥利质量流量计发展及应用现状

简要回顾科里奥利质量流量计的发展过程,着重总结了其国内外发展情况及应用现状,并指出其发展趋势。     

Performance evaluation of Coriolis mass flow meter in laminar flow regime

In many fluid flow applications, mass flow rate is preferred over volume flow rate, as it is more beneficial in terms of cost and material balance calculations. Coriolis mass flow meter (CMFM) is accepted widely for mass flow measurement owing to its accuracy and reliability. However, it has been found to under-read the mass flow rate in laminar flow region [1], thus limiting its application in this region. The secondary flow in the curved tube section influences the generated Coriolis force and leads to a deviation in meter readings. Commercial CMFMs are available with various curved tube configurations and need to be analyzed for their application in laminar region. This paper presents comprehensive experimental and numerical investigations performed to evaluate the influence of tube configuration and other meter parameters, such as drive frequency, amplitude of vibration, and sensor position, on the performance of the CMFM in laminar region. The findings of this study have put forth a suitable combination of tube configuration, drive frequency, and sensor position while using the CMFM in laminar flow regime.     

椭圆齿轮计量系统的改进

以加油站椭圆齿轮流量计计量系统为改造对象,针对原有系统功能单一、只能记录流量值、无法满足现代化要求等缺点,对系统进行了改造,使新增单片机控制系统和上位机系统实现如下功能：实时显示计量值;实时换算,显示每次加油费用;设置需加油最大值;通过总线技术与上位机通信,实时设置汽油单价;通过上位机实时记录每次加油产生的费用和油量值,同时把数据传至开票处开票。     

"V"型内锥式流量计的应用前景

长期以来,标准孔板由于其发展技术成熟、标准化程度高、结构简单等特点在过热蒸汽流量计量中得到非常广泛的应用.然而,孔板流量计存在着一些固有的缺陷,如流出系数不稳定、线形差、重复性不高、准确度受客观因素制约而无法达到设计要求、量程比小、压损大等.本文介绍"V"型内锥式差压流量计的工作原理,分析了如何解决孔板流量计的这些缺陷,并通过计算实例介绍"V"型内锥式流量计在节能方面的优点,最后介绍在恶劣条件下"V"型内锥式流量计是如何提供准确计量的.     

Experimental research of single-hole and multi-hole orifice gas flow meters

As energy efficiency is becoming more important today due to limited energy resources as well as their rising prices and environment issues, it is crucial to have reliable measurement data of different fluids in production processes. Because of its simplicity, affordability and reliability, orifice flow meters are again becoming subject of numerous researches. Conventional single-hole orifice (SHO) flow meter has many advantages but also some disadvantages like higher pressure drop, slower pressure recovery, lower discharge coefficient etc. Some of these disadvantages can be overcame by multi-hole orifice (MHO) flow meter while still maintaining advantages of conventional SHO meter. Both SHO and MHO flow meters with same β ratios were experimentally tested and compared. Results showed better (lower) singular pressure loss coefficient and lower pressure drop in favour of the MHO flow meter. Experimental data indicates that MHO flow meter is superior to the conventional orifice flow meter, but further research is necessary to make the MHO a drop-in replacement for a SHO flow meter.     

Calculation of the virtual current in an electromagnetic flow meter with one bubble using 3D model

Based on the theory of electromagnetic induction flow measurement, the Laplace equation in a complicated three-dimensional (3D) domain is solved by an alternating method. Virtual current potentials are obtained for an electromagnetic flow meter with one spherical bubble inside. The solutions are used to investigate the effects of bubble size and bubble position on the virtual current. Comparisons are done among the cases of 2D and 3D models, and of point electrode and large electrode. The results show that the 2D model overestimates the effect, while large electrodes are least sensitive to the bubble. This paper offers fundamentals for the study of the behavior of an electromagnetic flow meter in multiphase flow. For application, the results provide a possible way to estimate errors of the flow meter caused by multiphase flow.     

Sheathed probe thermal gas mass flow meter heat transfer analysis

The thermal gas mass flow meter is an important meter used in industrial measurement. When the environmental temperature changes, the measured gas physical parameters change correspondingly and the thermal gas mass flow meter output signal is affected, causing large measurement error. The influence of gas temperature on the sheathed probe measurements is analyzed in this paper based on experiments and heat transfer theory using a three dimensional probe and gas heat transfer mathematical model based on the heat conduction equation. The probe heat transfer process is analyzed under convection heat transfer coupling conditions. The experimental data were analyzed and compared against the theoretical results, with a maximum average relative error of only 4.56%. The rationality of the theoretical method is thus verified.