流出系数和可膨胀性系数对差压式流量计计量影响的分析与研究  

Analysis and study on the effects of outflow coefficient and scalability coefficient on differential pressure flow meter measurement

作　　者：周文辉 冯鑫 ZHOU Wenhui;FENG Xin(Institute Offlow Metering Technology,Henan Institute of Metrology,Henan Zhengzhou 450008,China)

机构地区：[1]河南省计量测试科学研究院流量计量技术研究所,河南郑州450008

出　　处：《工业仪表与自动化装置》2025年第2期117-121,128,共6页Industrial Instrumentation & Automation

摘　　要：差压式流量计在计量天然气输送管道的流量时,流出系数C因节流装置磨损、管道内杂质堆积改变流态等原因偏离标准值,影响计量精准性;可膨胀性系数ε受输送中压力与温度频繁变化、天然气成分波动等问题,进而使计量结果不准。基于此,该研究分析了这两个系数对差压式流量计计量结果的影响,并探讨了减少计量误差的方法。该研究以标准孔板为节流件的差压式流量计的测量原理及其使用极限条件为基础,以某热力公司差压式流量计计量过热蒸汽的节流装置设计为例,按照JJG1003—2016检定规程,在考虑系数随温压改变的情况下获取实验数据。通过实验得出以下结论:当压力浮动17%、温度浮动9%时,流出系数最大变化幅度为0.07%,可膨胀性系数最大变化幅度为0.9%。在不同的流量信号和补偿信号下,流出系数改变与不变时,仪表示值会存在不同的误差。When measuring the flow rate of natural gas transmission pipelines using differential pressure flow meters,the outflow coefficient C deviates from the standard value due to wear of throttling devices,accumulation of impurities in the pipeline,and changes in flow state,which affects the accuracy of measurement.The coefficient of expandability ε is affected by frequent changes in pressure and temperature during transportation,as well as fluctuations in natural gas composition,which can lead to inaccurate measurement results.Based on this,this study analyzed the impact of these two coefficients on the measurement results of differential pressure flow meters and explored methods to reduce measurement errors.This study is based on the measurement principle and usage limit conditions of a differential pressure flowmeter with a standard orifice plate as the throttling element.Taking the throttling device design of a differential pressure flowmeter for measuring superheated steam in a certain thermal company as an example,experimental data was obtained according to the JJG1003—2016 calibration regulation,considering the coefficient changing with temperature and pressure.The following conclusion was drawn through experiments:when the pressure fluctuates by 17%and the temperature fluctuates by 9%,the maximum change in outflow coefficient is 0.07%,and the maximum change in expansion coefficient is 0.9%.When the outflow coefficient changes and remains constant under different flow signals and compensation signals,there will be different errors in the instrument readings.

关 键 词：差压式流量计 流出系数 可膨胀性系数 流量积算仪 数学模型 

分 类 号：TM614[电气工程—电力系统及自动化]