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- 2017
速度分布对气体超声流量计声传播规律的影响
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Abstract:
气体超声流量计广泛应用于天然气贸易计量, 在实际工业现场, 由于流态和流速的不同, 使得超声波传播特性呈现不同的规律．为了研究这一规律的变化特征, 文中提出了一种基于COMSOL仿真的射线追踪方法来模拟单声道气体超声流量计的测量过程, 并验证了该仿真方法的正确性．选取充分发展湍流和单弯头下游的速度分布为研究对象, 以5个不同的速度点为入口流速, 讨论超声波传播轨迹、传播时间、轨迹偏移量、声压分布等参数随流速、流态的变化规律, 进而分析其对流量测量的影响, 提出一种改善测量误差的修正方法, 使测量误差最大降低约4% , 达到修正效果．
Gas ultrasonic flowmeter is widely used in the natural gas trade measurement. However，in the actual industrial field，due to the different flow patterns and flow velocities，the ultrasonic propagation presents different characteristics. In order to study the laws of ultrasonic propagation，a ray tracing method based on COMSOL is proposed to simulate the measurement process of single channel gas ultrasonic flowmeter，and the correctness of the simulation method is verified. The velocity distributions of fully developed turbulence and single elbow are selected as measurement object. For five different inlet velocities，the laws governing the changes of ultrasonic propagation trajectory，time，deviation and pressure distribution with flow velocity and flow pattern are discussed. Furthermore，the influence of the change laws on the flow measurement is analyzed. Besides，a correction method to reduce measurement error is proposed，which can achieve satisfactory correction effect with the maximum measurement error decrease of 4%
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