科里奥利质量流量计密度效应研究

本文旨在通过研究传感器与被测介质之间的力学关系，提出一种科里奥利质量流量计在不同介质密度下测量误差不一致的形成机理，为提高计量精度以及误差修正提供理论依据。结果表明：以U形管科里奥利质量流量计为例，振动管水平段因扭转变形而形成速度梯度，并存在与科氏力扭转方向相反的转矩，最终造成科里奥利质量流量计的计量误差随介质密度而改变。研究了传感器在介质流动时的受力状况，建立了传感器关于密度效应的数学模型，并提出了计算公式及简化方法。

Study on Error Caused by Density Effect of Coriolis Mass Flowmeter

This article proposed a mechanism to explain error of Coriolis mass flowmeter in testing different density.The results showed that the upper segment of tube in U shape had velocity gradient when torsion triggered by Coriolis force, thus produced an adverse torque to reduce time difference and finally created the negative calibration errors. The mathematical model was built to precisely calculate magnitude of the effect caused by different density and other factors such as the dimension of sensor. The simplified way to choose value of density for calculation was given out due to limit of calibration method and experiment condition. In addition, it was proved that the error was directly proportional to density, but not related to flowrate. The application of this theory improves the accuracy grade of Coriolis mass flowmeter in measuring compressed natural gas(CNG) and paves the way to the correction algorithm in the future.