气体超声波流量计整流装置设计与仿真分析

Design and Numerical Simulation of Flow Conditioner for Ultrasonic Flowmeter

针对超声波流量计易受管道内流态畸变影响的特点,设计了一款由叶片式起旋器、直管混合腔与蜂窝整直器构成的复合整流装置,加装在超声波流量计上游。运用大涡模拟方法对无/有双弯头+半开平板扰流条件下超声波流量计内部的流场进行仿真,分析了测量声道上的速度分布以及整流装置安装间距对其产生的影响,评估了整流装置的性能。结果表明,无整流装置时测量声道上的速度分布出现严重偏斜和畸变,其测量速度与真实流速偏差高达20%;有整流装置时声道上测量速度的偏差降至2.0%以内,整流效果显著。此外,整流装置距上游扰流件不小于5倍管径即可满足其安装要求,大大缩短了超声波流量计对上游直管段的长度要求。设计的复合整流装置拓宽了超声波流量计的实际应用范围。今后将进一步对起旋器结构进行优化以提升其整流效果。

Aiming at the characteristic that ultrasonic flowmeter is liable to be affected by the flow pattern distortion in pipeline,a composite rectifying device composed of blade type swirler,straight pipe mixing chamber and honeycomb straightener is designed,which is installed in the upstream of ultrasonic flowmeter.The flow field inside the ultrasonic flowmeter under the condition with or without double elbow plus half-open plate turbulence is simulated by using the large eddy simulation method.The influence of velocity distribution on the measured channel and the spacing between rectifiers installation is analyzed.The performance of the rectifiers is evaluated.The results show that the velocity distribution on the measured channel is seriously skewed and distorted without a retifier,and the deviation between the measured velocity and the real velocity is as high as 20%.When there is a rectifier device,the deviation of the measured speed on the channel is reduced to less than 2.0%,and the rectification effect is significant.In addition,the rectifying device is no less than 5 pipe diameters away from the upstream spoiler to satisfy the installation requirements,which greatly reduces the length requirements of the upstream straight pipe segment of the ultrasonic flowmeter.The design of composite rectifier device amplifies the practical application range of ultrasonic flowmeter.In the future.The structure of the swirler will be further optimized to improve its rectification effect.