【作者】 姚平；

【导师】 傅新；

【作者基本信息】 浙江大学 ， 机械电子工程， 2018， 硕士

【摘要】 我国是一个天然气消耗大国,天然气的计量设备会随着天然气的使用增加而发展。气体超声流量计相对于传统流量计,具有突出优势,因此必定会得到广泛应用。在实际应用的过程中,由于安装空间有限,会出现弯管或者双弯管等安装情况,导致流场复杂,流量计的测量精度不高。因此研究复杂流场下的气体超声波流量计测量精度提升方法显得尤为重要。本论文主要针对复杂流场下气体超声波流量计测量精度进行研究,具体研究内容如下:(1)整流器对气超声测量精度的影响。针对市场上常用的Sick整流器和Elster整流器进行数值仿真研究,选出整流效果较佳的整流器。针对整流效果较佳的整流器,分别进行单弯管和双弯管安装环境下的数值仿真研究,探索出对安装空间要求较小而整流效果性能较佳的安装位置。(2)滤波算法对气超声测量精度的影响。采用MATLAB对几种常用的流量滤波算法进行编程,随后采用SD卡模块进行实流数据采集,将采集的原始流量数据作为各个滤波算法的输入值,分析比较各个滤波算法在相同区间的标准差。选用标准差最小的滤波算法。(3)仪表系数修正算法对气超声测量精度的影响。分析目前实际的仪表系数曲线,然后分析几种修正算法的优点和缺点,针对具体的应用环境,提出相应的仪表系数修正算法。经过仪表系数修正后的仪表能够达到1.0级精度表的要求。(4)快速标定方法的实验验证。通过实流标定实验验证整流器安装位置的合理性、滤波算法的有效性、仪表系数修正算法的有效性,最终提高气体超声波流量计的测量精度。更多还原

【Abstract】 China is a large natural gas consuming country,and the need for the development of natural gas metering equipment will grow with the increasing use of natural gas.Gas ultra-sonic flow meter relative to the traditional flow meter,has outstanding advantages,it will certainly be widely used.In the practical application process,due to the installation space is limited,the emergence of elbow or double elbow and other installation,leading to com-plex flow field,flowmeter measurement accuracy is not high.Therefore,it is very im-portant to study the measurement accuracy improvement of gas ultrasonic flowmeter in complex flow field.In this dissertation,the measurement precision of gas ultrasonic flowmeter under complex flow field is mainly studied.The main contents are as follows:(1)Rectifier on gas ultrasonic measurement accuracy.For the Sick Rectifier and Elster Rectifier commonly used in the market numerical simulation study,select the rectification better rectifier.For rectifiers with better rectification effect,the numerical simulations under single-bends and double-bends were carried out,respectively,and the installation positions with smaller installation requirements and better rectification per-formance were explored.(2)The influence of filtering algorithm on gas ultrasonic measurement accuracy.Several commonly used traffic filtering algorithms are programmed by MATLAB.Then SD card module is used for real-time data acquisition.The original traffic data is taken as the input value of each filtering algorithm,and the standard deviation of each filtering algorithm in the same interval is analyzed and compared.Selection of the smallest standard deviation filter algorithm.(3)Instrument coefficient correction algorithm on the gas ultrasonic measurement accuracy.Analyze the current actual instrument coefficient curve,and then analyze the advantages and disadvantages of several correction algorithms.For the specific application environment,propose the corresponding instrument coefficient correction algorithm.After the meter factor correction of the instrument to achieve 1.0 accuracy table requirements.(4)Rapid calibration method of experimental verification.Through the calibration of actual flow,the rationality of the installation position of the rectifier,the effectiveness of the filtering algorithm and the effectiveness of the instrument coefficient correction algo-rithm are verified,and the measurement precision of the gas ultrasonic flowmeter is finally increased.更多还原