基于收缩流动的气体超声流量计声道稀疏化及测量方法

为了提高低声道数超声流量计的准确度水平,在传统超声流量计的基础上设计了一种具有收缩流动结构的低声道数超声流量计。采用数值模拟研究了渐缩管中收缩流动的流场特征,确定了渐缩管的几何参数及超声探头的安装方式。通过空气实流实验,研究了单声道及双声道在收缩流动条件下流量计量的基本特性。在流量范围27~432m3/h,管径范围100~150mm进行了实验验证。结果表明:收缩流动的数值模拟结果与理论模型相吻合,当渐缩管的收缩比由2增大为6,被测流场均匀区占比显著增大;当收缩比固定不变时,随着流量的增大,边界层厚度显著降低。通过实流实验比较不同结构和配置超声流量计的测量结果,发现单声道收缩管超声流量计的准确度水平显著优于传统单声道气体超声流量计,与传统双声道气体超声流量计的准确度水平相当。

Channel Thinning and the Measurement Method of Gas Ultrasonic Flowmeter Based on Contraction Flow

In order to improve the accuracy level of the low-channel number ultrasonic flowmeter, a low-channel number ultrasonic flowmeter with a shrinking flow structure was designed on the basis of the traditional ultrasonic flowmeter. Focusing on the research content, numerical simulation was used to study the flow field characteristics of the shrinking flow in the reducer, and the geometric parameters of the reducer and the installation method of the ultrasonic probe were determined. Through the air flow experiment, the basic characteristics of the flow measurement of mono and dual channels under contracting flow conditions were studied. The scope of flow studied is 27~432m3/h and the range of pipe diameter is 100~150mm. The research results show that the numerical simulation results of shrinkage flow are consistent with the theoretical model. When the shrinkage ratio of the reducer increases from 2 to 6, the proportion of the uniform area of the measured flow field increases significantly. When the shrinkage ratio is fixed, as the flow rate increases, the boundary layer thickness decreases significantly. Compare the measurement results of ultrasonic flowmeters with different structures and configurations through real flow experiments.The accuracy of the actual flow measurement of single-channel gas ultrasonic flowmeter is superior to that of the traditional single-channel gas ultrasonic flowmeter significantly and is equivalent to the traditional dual-channel gas ultrasonic flowmeter.