气固两相流质量流量测量的新方法

文提出了一种采用电容传感器测量气固两相流质量流量的新方法。通过电容传感器对固相浓度的测量,可以求出气固两相流的固气比,结合气固混合之前所测得的载气流量,便可测出固相的质量流量。实测结果显示,测量误差小于5     

基于双弯管法的稀相固相质量流量测量北大核心CSCD

双弯管法固相质量流量测量方法是以弯管流量计为基础,可实时测量气固两相流固相质量流量的方法。在前人研究的基础上对双弯管法固相质量流量测量模型进行了优化改进,建立了考虑气固两相流固相体积时的数学模型,并进行了实验研究,给出了基于新模型的固相质量流量计算公式。实验结果表明:新数学模型可以提高固相质量流量的测量精度,降低测量误差,与实际情况更加接近。     

气固两相流中基于神经网络的固相质量流量检测方法的研究

用神经网络的自学习算法对采样数据进行辨识得出固相质量流量的黑箱模型，实现固相质量流量的在线测量。实验结果，模型最大测量误差为１０％     

基于静电传感器的气固两相流质量流量测量方法的研究

固相微粒的体积浓度和平均速度是测量两相流质量流量的2个关键参数。本文研究了基于静电传感器的双参数法测量质量流量的新方法。对体积浓度的测量,首先通过对系统等效电路的分析及求解泊松方程并结合体积浓度与空间电荷密度的关系,建立了传感器输出电压与体积浓度之间的数学模型,而对固相速度的测量则采用了波形法,记录通过上、下游传感器的时间差,计算出固相速度。在得到固相体积浓度与速度的基础上,由质量流量的计算公式即可得到两相流的质量流量。     

三相流分相浓度测量平台的标定试验

根据多相流流动特性对固相质量流量及流速之间的依赖关系,通过在以气力输送系统为基础的煤粉/生物质/空气三相流分相浓度测量系统实验平台上,对固相质量流量及风速分别进行了标定试验.结合标定结果将固体颗粒质量流量转换成所需的固相体积浓度,最终达到测量系统的测试要求.     

基于双截面ECT的气/固两相流参数检测系统

为了实现多相流的流动过程在线监测和多参数测量,设计并研发了一套应用于气/固两相流检测的双截面8电极电容层析成像系统.采用交流法电容检测原理实现具有16个独立电容检测通道的电容测量电路,实测系统的成像速度为590帧/秒.将双截面电容层析成像系统用于气/固两相流的实时检测,并将两层截面的图像作相关计算,获取成像截面的固相速度分布.由固相速度和浓度最终算出气/固两相流的固相质量流量,从而实现气/固两相流浓度、速度、流量等多参数的综合检测.将双截面ECT传感器算得的质量流量与发料罐重力传感器获取的质量流量作对比发现,两者具有较好的一致性,流量测量误差小于8％.     

工业气固两相流质量流量检测的研究

本文介绍了气固两相流量检测技术在工业生产中应用的意义及现状；基于相浓度＋速度原理的相关质量流量测量系统的原理；以及基于上述原理的电容式气固两相流流量计的工作原理及特点。     

基于双弯管法的稀相固相质量流量测量

双弯管法固相质量流量测量方法是以弯管流量计为基础,可实时测量气固两相流固相质量流量的方法。在前人研究的基础上对双弯管法固相质量流量测量模型进行了优化改进,建立了考虑气固两相流固相体积时的数学模型,并进行了实验研究,给出了基于新模型的固相质量流量计算公式。实验结果表明:新数学模型可以提高固相质量流量的测量精度,降低测量误差,与实际情况更加接近。     

压力信号干扰抑制的质量流量数据融合研究

质量流量测量精度受压力的影响,且随着压力的增大其测量精度变差。采用多个质量流量传感器进行多处测量,对质量流量测量数据进行自适应加权融合。在此基础上,为了消除压力对流量测量值的影响,采用BP神经网络进行压力干扰抑制的质量流量数据融合研究。研究结果表明,BP神经网络质量流量融合值的精度较自适应加权融合值的精度大大提高,且附加动量法获得的BP网络融合精度最高,自适应学习速率调整法次之,梯度下降法最差。     

静电感应式粉粒体质量流量测量方法的研究

质量流量的在线测量对生产的控制及生产效率的提高具有重要意义。基于点电荷的概念,设计了粉粒体质量流量传感器的静电感应实验装置,实验研究了带电颗粒在敏感区域中不同位置的传感器感应特性。针对不同的流动参数,对质量流量的测量进行了仿真研究。实验及仿真结果表明：环式静电感应传感器适合于测量流速均匀分布或者流速值分布固定的粉粒体质量流量。     

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。     

科氏流量计应用于气液两相流测量的实验研究

以空气-水为介质,对科氏流量计应用于气液两相流双参数测量进行了实验研究.实验过程中保持液相流量一定,通过加入不同体积分数的空气来分析含气率对科氏流量计测量精度的影响,采用Weisman垂直上升管气液两相流流型图与实验数据进行了比较.结合实验结果,初步归纳出含气量、流型和科氏流量计测量精度之间的关系,总结出液相中含气影响科氏流量计测量精度的主要因素及其影响规律,为进一步研究科氏流量计气液两相流测量误差修正提供了一种技术方法.     

锥形孔板在气液两相流量测量中的应用

通过对利用差压脉动特性,来测量汽液两相流量的2种测量方法分析后,发现尽管两种测量模型不同,但其测量机理相似。于是借鉴2种测量模型各自的优点,选定了测量方法。在完成对标准孔板改进后,结合此测量方法,实现运用单一节流件,完成了汽液两相流量的双参数测量。试验结果表明,干度的测量误差≤±4.9%,质量流量测量误差≤±9.7,而且在试验范围内B和x基本呈现单值函数关系。     

Review of certain key issues in indirect measurements of the mass flow rate of solids in pneumatic conveying pipelines

On-line mass flow measurement of particulate solids in pneumatic conveying pipeline is a technically challenging area, where mass flow measurement presents a range of problems. These problems are not normally relevant to a single phase flow, but are always involved in gas–solids two-phase flows, like inhomogeneous distribution of solids over the pipe cross section, irregular velocity profiles, variations in particle size, moisture content, and deposition of fine particles on the inner wall of the pipeline. These variables may affect the response of a solids flow meter in ill-defined ways. All of these make the design and the calibration of solids’ mass flowmeter more difficult. Based on a review of non-invasive mass flow measurements of particulate solids, this paper summarizes and highlights several key issues, which often rely on structures of sensors or measurement methods, in indirect mass flow metering of pneumatically conveyed solids. They are: (i) spatial filtering effect; (ii) averaging effect; (iii) measurement resolution and sensitivity of array structures in tomography sensors.     

Review of techniques for the mass flow rate measurement of pneumatically conveyed solids

An accurate, reliable, on-line, continuous and non-invasive measurement of solids’ mass flow rate in pneumatic conveying pipelines has been a technically challenging area, which becomes increasingly significant to achieve efficient utilization of energy and raw materials and to reduce waste. Energy and environmental regulation and legislation, and efficiency and waste reduction are two most powerful drivers in the academic research and industrial applications for solids’ mass flow meters. In this paper, a review is presented on the recent measurement techniques of solids’ mass flow rate measurement in pneumatic conveying systems. On basic principle and configuration of each technique, performances and limitations of these techniques in industrial applications are analyzed and compared from different views to demonstrate the recent developments in the field and the possible approaches which may provide solutions to the solids’ mass flow measurement problem.     

数字信号处理技术在科氏质量流量计中的应用

科氏质量流量计是目前应用范围最广、发展速度最快的流量计之一。数字信号处理技术是科氏质量流量计的核心技术,直接决定其测量精度、测量稳定性等性能指标;而流量传感器输出信号的数学模型是信号处理的依据和基础。国内外学者提出了多种信号处理方法,但是,没有根据不同的信号模型和不同的应用场合对各种信号处理方法进行比较和评价。为此,根据不同数字信号处理方法的特征量提取原理,分析了其具有的优缺点。针对科氏质量流量计单相流、批料流与气液两相流测量这3种典型应用场合中存在的关键技术问题,依据随机游动信号模型、突变信号模型和自回归滑动平均(ARMA)信号模型,分别从计算精度、响应速度、收敛性、抗干扰能力和对参数变化的敏感度等方面,对不同信号处理方法进行考核和对比,确定了3种典型应用场合下,解决关键技术问题,性能最佳的数字信号处理方法。     

The primary dynamic gravimetric system for gas mass flow measurement

High accuracy mass flow measurement is an enabling technology at the base of many industries. HORIBA STEC Co., Ltd. developed its own primary gas mass flow measurement system. We employed the dynamic gravimetric method in a vacuum chamber, and we use only mass and time information for mass flow rate calculation, with no correction for temperature, pressure and humidity. The system achieved 0.036% uncertainty as lowest of results with satisfactory performance of proficiency testing with NIST (National Institute of Standards and Technology). Then the laboratory has been granted ISO/IEC 17025 accreditation since 2017. This paper describes the system details and uncertainty analysis.     

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.     

A new method of two-phase flow measurement by orifice plate differential pressure noise

The mechanism of differential pressure noise of orifices in two-phase flow has been investigated and a theoretical model has been developed for measurement of the double parameters, i.e. mass flow rate as well as phase fraction (steam quality). The model has been proved in a set of orifice experiments in a two-phase flow system at a pressure range of 5.8–12.1 MPa and steam quality of 0.05–0.95, and a practical model has been fitted. The r.m.s. errors of mass flow rate and steam quality estimated by the model are 9.0 and 6.5%, respectively. The results of the studies create a method to measure double parameters of two-phase flow at once using only a single orifice.