A new structure is proposed for a DN25-type ultrasonic gas flow meter with a V-shape double sound channel arrangement. The flow field characteristics are analyzed including velocity curves for the four channel lines, velocity profiles for different cross-sections of the flow meter, and streamlines of the transducer channel sections. The metering characteristics of the flowmeter are measured using a Venturi nozzle device. When the pipeline flow rate is less than 2.26 m/s, the pipe installation does not have a significant effect on the velocity profile and the velocity in the channel lines. However, the error in the low-flow region is large, and the flow distortion directly affects the measurement accuracy. When an ultrasonic gas flow meter with an accuracy class of 1.5 is used with pipes containing a single or double bend upstream, the linear error doubles, low-flow error becomes a negative deviation, and reference error in the low-flow region becomes approximately 700%–949%. The installation structure of the first pair of transducers also affects the signal propagation of the transducers behind it. Therefore, it is critical to process the ultrasonic signal according to the flow field distribution and adopt different weighted algorithms to obtain accurate pipeline flow rates to improve the measurement accuracy of the ultrasonic flow meter.

提出了一种具有V形双声通道布置的DN25型超声气体流量计的新结构。分析了流场特性，包括四个通道线的速度曲线，流量计不同横截面的速度曲线以及换能器通道部分的流线。使用文丘里喷嘴装置测量流量计的计量特性。当管道流速小于2.26 m / s时，管道安装不会对速度曲线和通道中的速度产生重大影响。但是，低流量区域的误差较大，并且流量畸变直接影响测量精度。当将精度等级为1.5的超声波气体流量计用于上游具有单弯或双弯的管道时，线性误差加倍，低流量误差变为负偏差，低流量区域的参考误差约为700％–949％。第一对换能器的安装结构也影响其后面的换能器的信号传播。因此，根据流场分布对超声信号进行处理并采用不同的加权算法来获得准确的管道流速至关重要，以提高超声流量计的测量精度至关重要。