高速气体流量计校准系统研究

发布时间：2018-04-18 09:05

本文选题：高速气体 + 流量计校准　；参考：《东华理工大学》2015年硕士论文

【摘要】：为了解决标准表法校准系统无法进行高速气体流量校准的问题,本文依据正压标准表法设计了一套高速气体流量计校准系统。通过对系统的不确定度理论分析,并借助计算机流体仿真技术CFD对系统的结构进行了仿真分析,论证了系统设计方案的可行性。本系统通过空压机提供气源,气体通过前储气罐后流向标准表区,其后经由后储气罐流向待测表区。通过改变三路管径分别为DN20、DN50和DN50的标准管道阀门开度,选通三路管径分别为DN20、DN32和DN50的待测表管道,实现气体流量计从低速到高速的流量校准,其中三路标准表和三路待校准表的安装位置为通过CFD仿真确定的。系统采用PLC-CPU224作为主控制器,以电动调节阀为被控对象,通过PID算法和阀门开环控制调节阀门开度进而实现管道流速的控制,其中系统的闭环控制传递函数及整定参数为通过机理法和阶跃响应法结合使用,并借助于Matlab工具Simulink仿真得出的。在实际运行过程中将系统的过程量利用组态软件MCGS进行实时显示,并实时改变流量设定量和阀门开度值。经过对系统的校准范围、控制相对误差、不确定度、重复性和稳定性的实验研究,结果表明:校准系统的扩展不确定度为0.76%;流量校准范围为10-910m3/h(对应的在DN50管道内的流速范围为1.4-128.7m/s);系统的控制相对误差和校准相对误差都在1%以内。
[Abstract]:In order to solve the problem that the calibration system of standard meter can not carry out high speed gas flow calibration, a calibration system of high speed gas Flowmeter is designed according to the positive pressure standard meter method in this paper.By analyzing the uncertainty theory of the system and using the computer fluid simulation technology CFD, the structure of the system is simulated and analyzed, and the feasibility of the system design scheme is proved.The system provides the air source through the air compressor, the gas flows through the front tank to the standard meter area, and then through the rear gas storage tank to the area to be measured.By changing the opening degree of the standard pipe valve with the diameter of DN20 / DN50 and DN50 respectively, and selecting the pipeline to be measured with the diameter of DN20 / DN32 and DN50 respectively, the flow calibration of gas Flowmeter from low speed to high speed can be realized.The installation positions of three standard tables and three channels to be calibrated are determined by CFD simulation.The system adopts PLC-CPU224 as the main controller and the electric regulating valve as the controlled object. Through the PID algorithm and the valve open loop control the valve opening to realize the control of the pipeline velocity.The closed-loop control transfer function and tuning parameters of the system are obtained by the combination of mechanism method and step response method, and by means of Simulink simulation with Matlab tool.The process quantity of the system is displayed in real time by configuration software MCGS, and the flow setting and valve opening value are changed in real time.After an experimental study of the calibration range of the system, the control of relative error, uncertainty, repeatability and stability,The results show that the extended uncertainty of the calibration system is 0.76, the flow calibration range is 10-910m3 / h (the corresponding velocity range in the DN50 pipeline is 1.4-128.7 m / s ~ (-1)), and the control relative error and the calibration relative error are within 1%.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH814

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