温压补偿型超声气体质量流量计

对超声时差法进行算法改进后，结合气体密度公式推导出超声质量流量方程，据此设计出温压补偿型超声气体质量流量计，给出了流量计核心系统及温压补偿部分的硬件设计。将只用于流体体积流量测量的超声流量计推广到气体质量流量测量领域，使超声流量计趋向理想化。经实验证明此流量计在测量常压空气时精度可达1．42％。     

密度偏差对气体流量测量的影响分析

介绍用标准节流式差压流量计测量气体流量的方法及原理,以及气体流量测量中温度、压力补偿的必要性和公式推导。列举在实际工作中气体流量测量的应用,将由于介质密度取值偏离及工况介质组分改变等最终影响流量测量准确性的情况进行分析比较。学会计算调整差压量程,复核验证补偿系数,熟悉工艺工况对从事自动化控制的仪表技术人员来说非常重要。     

饱和气体流量测量的温压自动补偿

在工业气体中,有一部分是饱和气体,如焦炉煤气、高炉煤气。提高对这类气体的计量水平,是发展生产,加强能源管理的现实需要。迄今,对气体的流量测量主要是采用差压流量计。人们已经熟识,由于气体的密度是温度、压力的函数,所以,在流量测量中必须进行温压补偿以抵消由于密度的变化对流量测量的影响。对于饱和气体,其密度除了受温压影响外,还受湿度的影响。而饱和气体的绝对湿度是温度的单值函数。这就提供了可能,在进行温压补偿时,可同时考虑克服湿度的影响。输送饱和气体的管道,经常有冷凝水存在,然后通过水封排掉。当温度下降,绝对湿度减     

简谈流量的温压补偿及液位的密度补偿计算

本文对工业生产过程中气体及蒸汽的流量测量进行温压补偿的基本公式进行了推导,对某些受温度影响较大而密度变化亦较大的介质液位测量进行密度补偿的基本公式进行了推导,指明应依据被补偿介质的特性选择不同的温压补偿公式及补偿方法,同时指出了流量及液位补偿中应注意的一些事项。     

气体质量流量与压力的测量和控制

本文介绍气体质量流量的测量和控制及微压传感器的原理及应用.     

基于热膜探头的新型气体流量传感器研究

基于热膜探头的热传递原理,设计了一种新型的气体流量传感器.首先研究了在不同环境温度和电流下热膜探头的温度特性,确定其工作电流.然后分析热膜探头中测量电阻和补偿电阻之间的关系,设计了具有温度补偿功能的气体流量传感器电路,减小了环境温度对气体流量测量的影响.最后根据气体流量标定实验数据,建立了流量传感器的数学模型.实验结果表明,该气体流量传感器具有较好的一致性,测量精度优于0.8%,流量量程比达100∶1.     

流量测量温压补偿装置

众所周知,单回路控制仪表以其高的可靠性和优良的性能而得到了广泛应用,其中YS-80系列内SPLR可编程运算器,当用于气体、蒸流流量测量作温度,压力补偿时特别方便。由于其特殊的功能,使补偿装置的组成,除了变送器之外,只要一台SPLR可编程运算器、一台配电器和一个计数器就可以了,与使用单元组合仪表相比特别简单,特别方便。在气体的流量测量中,因压力、温度的变化,被测介质的密度不同于设计条件,因而需要进行温压补偿(在压力较低或变化较小时,压缩系数的影响可不考虑),其补偿公式为     

基于数据融合的流量式泄漏检测温度补偿方法研究

传统的气体泄漏检测方法往往将泄漏量作为差压信号的一元函数处理,但由于气体对温度变化的敏感性,使得温度成为影响泄漏检测精度及稳定性的重要因素.文章结合流量式泄漏检测给出了基于数据融合理论的温度补偿模型,并探讨了环境温度对检测过程中两腔压力、温度及差压信号的影响规律,总结了流量式泄漏检测中的环境温度修正方法.     

GAS流量温压补偿在DCS中的设计与应用

GAS流量的温度压力补偿是工业流量检测中经常遇到的问题。本文着重阐述了GAS流量测量在横河DCS系统中的应用及其流量温压补偿的计算校正与设计。     

准平衡态下的流量式泄漏检测容积补偿研究

为研究并联型流量式气体泄漏检测中容器容积与泄漏量之间的内在关系,解决检测中的多参数耦合问题,从泄漏检测机理出发,通过分析检测过程中的准平衡状态,把压力变化率作为搭建基准容器与被测容器间的桥梁,建立了适用于并联型流量式泄漏检测的容积补偿模型,并提取层流管流量与泄漏量关系中的容积影响因子作为容积补偿系数。实验结果验证了模型的正确性,即采用容积补偿的方法,能初步建立起泄漏量与差压信号间的线性关系。     

减压阀流量压力特性的分析与探讨

分析了减压阀的流量、压力、压力差和阀门开工的关系。通过设计一些典型的工况实例，从实际运用的角度对减压阀工作过程进行了分析研究。     

Model analysis for differential pressure two-phase flow rate meter in intermittent flow

Multiphase flow rate metering is a challenging problem, specially for flow patterns other than wet-gas. This paper brings forward a new comparative analysis of three differential pressure calibration models suited for liquid dominated two-phase flows, in a total of seven model configurations. First, the models are compared theoretically and classified in terms of the type of input data required. Then, experimental data of over 300 horizontal air–water experiments, for $1$” and $2$” pipe diameters, supports quantitative analyses of the prediction accuracies and sensitivity of the superficial velocities of gas and liquid to measurement errors in the model input variables. Finally, a method for assessing the decoupled measurement errors for the void fraction and gas velocity is shown, as these variables are typically subject to higher uncertainties. It results that, though the void fraction is shown to be systematically under evaluated in more than 10%, the total mass flow rate is estimated through the Paz et al. (2010) model with an overall root mean squared deviation (RMSD) of 5.75% for the $2$” data. Also, the use of gas velocity measurements, even if subject to considerable errors, decreased the RMSD for the gas superficial velocity by more than half for the $1$” data.     

脉动流对差压式流量计测量误差影响的研究

基于脉动流场中差压式流量计的计量特性，本文分析了差压式流量计在各种脉动流频率和幅度下的流量测量误差。针对不同脉动频率和脉动幅度的脉动流，在自行设计的实验装置中使用响应时间不同的差压式流量计进行流量测量的研究，获得了流量计响应时间、流体的脉动幅度和频率与流量测量误差间的变化对应关系。研究结果表明，通过减少脉动幅值和缩短流量计的响应时间可有效地减少流量测量误差。     

液固两相流压降规律及超声法压降测量

液固两相流广泛存在于能源动力、石油化工等工业过程,两相流压降作为重要的流动参数,有助于流动建模及流态分析。建立液固两相压降测量模型,提出了一种结合超声多普勒及超声透射衰减的液固两相超声压降测量方法。搭建液固两相流动实验平台,对两相压降规律进行研究。两相混合流速和固相体积分数升高时,液固两相压降均逐渐增加。在固相体积分数为0.28%～1.37%,两相混合流速为0.9～1.65 m/s时,根据液固两相压降测量模型及Churchill模型的超声法得到的两相压降与差压传感器测量的压降平均相对误差为4.93%和5.10%,验证了测量模型的准确性。针对非均匀分布的两相流态进行压降测量,进一步拓展了压降测量模型的应用范围。本研究工作为非侵入超声法测量液固两相压降提供了方法基础。     

气相色谱电子流量/压力控制模块研制和应用

为了提高气相色谱仪气路控制自动化水平,研制了电子流量/压力控制模块.该模块在基于闭环控制的方式上,通过小流量比例电磁阀、小流量和压力传感器、微型可调限流装置、颗粒过滤网、集成流路块体的优化设计,以放大基准电路、A/D转换、单片机控制系统PID、D/A转换、功率驱动电路来达到控制气体流量/压力的目的.再以单气路控制为最小...     

动态压差控制阀流场及流量控制特性研究

针对变流量加热及冷却系统水力和热力失调的问题,设计一种动态压差控制阀.基于计算流体力学(CFD)方法,建立不同阀芯开度下动态压差控制阀三维流道模型.对比研究了不同阀芯开度下阀内流场分布以及流量变化,得出了动态压差控制阀在不同阀芯开度下阀内压降曲线的变化规律、阀芯节流口处速度曲线及湍动能曲线的分布规律,拟合了阀门出口流量...     

Flow measurement based on the combination of swirler and differential pressure under slug flow

The alternating appearance of elongated bubbles and liquid slugs of slug flow in the pipe causes severe pressure fluctuation. As a result, measuring the flow rate of the slug flow with the throttling unit based differential pressure method is difficult. This paper investigates a new swirler-based flow measurement method in slug flow. The swirler converts the slug flow into a swirling annular flow, and the differential pressure method is used to measure the flow rate. The influences of gas and liquid flow rates on the differential pressure ΔP_X across the swirler as well as its downstream axial differential pressure ΔP_Z are investigated. ΔP_X^0.5 increases linearly as the liquid mass flow rate increases, and the slope of the curve increases as the gas mass flow rate increases. The influence of gas mass flow rate on ΔP_X^0.5 is comparable to that of liquid mass flow rate on ΔP_X^0.5. ΔP_Z^0.5 increases linearly with increasing gas/liquid mass flow rate, and the slope of the curve of ΔP_Z^0.5 with m_l differs slightly from the slope of the curve in single-phase water conditions. Based on the research presented above, new empirical correlations of mass flow rate based on ΔP_X and ΔP_Z are established respectively. The superficial liquid velocity ranges from 0.6 to 2 m per second, while the superficial gas velocity ranges from 2 to 6 m per second. If the gas mass flow rate and ΔP_X are known, the relative error of liquid mass flow is less than 3%. The relative error of the gas mass flow rate is less than 10% if the liquid mass flow rate and ΔP_X are given. The calculation accuracy of the flow measurement model using ΔP_X is better than the calculation accuracy of the flow measurement model using ΔP_Z.     

Fluctuant pressure coefficient of the wake behind a bluff body in mist flow

Fluctuant pressure coefficient is presented as an index of vortex energy of the wake behind a bluff body in mist flow. Calculation for vortex energy is obtained from inter-phase force analysis, based on Basset-Boussinesq-Oseen equation and conservation of mechanical energy. Vortex energy is weakened by liquid disturbance, the relationship between the fluctuant pressure coefficient and liquid velocity is set up on theory analysis. An existence criterion for vortex streets is proposed using the relationship. A new algorithm for prediction of liquid velocity is put forward and compared with the method in Higham's patent. The predicted results fit the experimental results well.     

温压补偿在MED装置蒸汽流量测量中的应用

为解决低温多效蒸馏（MED）淡化过程中蒸汽温度、压力波动引起的蒸汽流量测量不准确的问题,依托30t/d MED淡化中试装置,本文分析了进料蒸汽的温度、压力变化特点,研究选择适用于MED工艺的补偿公式和数学模型,并通过PLC控制实现补偿。结果表明：通过温度、压力补偿提高了MED蒸汽流量测量的准确度,增强了MED淡化系统的运行稳定性和经济性。     

Horizontally installed cone differential pressure meter wet gas flow performance

Differential pressure (DP) meters which utilise a cone as the system’s primary element are increasingly being used to measure wet natural gas flows (i.e. mixtures of natural gas, light hydrocarbon liquids and water). It is therefore important to understand this meter’s response to wet natural gas flows. Research into the wet gas response of the horizontally installed cone DP meter is discussed in this paper. Consideration is given to the significant influence of the liquid properties on wet gas flow patterns and the corresponding influence of the flow pattern on the cone DP meter’s liquid phase induced gas flow rate prediction error. A wet natural gas flow correlation for 4 in. 0.75 beta ratio cone DP meters with natural gas, hydrocarbon liquid and water flow has been developed from multiple data sets from three different wet gas flow test facilities. This corrects the liquid induced gas flow rate prediction error of a wet gas flow up to a Lockhart–Martinelli parameter of 0.3, for a known liquid flow rate of any hydrocarbon liquid/water ratio, to ±4% at a 95% confidence level.