弯管对超声波气体流量测量影响分析

Analysis of the Impact of Bend Pipe on Ultrasonic Gas Flow Measurement

摘要: 本研究针对弯管扰动导致超声波气体流量计测量精度下降的问题，开展流场理论分析与CFD仿真研究。基于时差法测量原理，建立流速分布与流量修正系数的数学模型，揭示弯管二次流对流速分布非对称性的影响机制。通过ANSYS软件对DN50弯管进行流场仿真，分析不同下游位置(1D-12D)的流速分布及相对误差变化规律。结果表明：弯管下游1D处流速相对误差高达24.91%，5D处趋于稳定(相对误差0.71%)，但10D后因流场恢复能力不足相对误差回升至9.26%，证实弯管扰动会对超声波流量计测量的准确性产生直接影响。本研究为提升超声波流量计在燃气计量中的精度提供理论支持。

Abstract: This study addresses the issue of reduced gas measurement accuracy in ultrasonic flowmeters caused by elbow disturbances through theoretical flow field analysis and CFD simulation. Based on the time-of-flight measurement principle, a mathematical model for velocity distribution and flow correction factors was established to reveal the mechanism by which secondary flow in elbows influences velocity distribution asymmetry. Flow field simulations of a DN50 elbow were conducted using ANSYS software to analyze velocity distribution and relative error patterns at different downstream positions (1D-12D). Results indicate: relative velocity error reaches 24.91% at 1D downstream of the bend, stabilizes at 5D (0.71% relative error), but rebounds to 9.26% beyond 10D due to insufficient flow field recovery capacity. This confirms elbow disturbances directly impact ultrasonic flowmeter measurement accuracy. This study provides theoretical support for enhancing the accuracy of ultrasonic flowmeters in gas metering applications.