电磁流量计在疏浚管道流速测量中的误差及修正

Flow Rate Measurement Error Using Electromagnetic Flowmeter in Pipeline Dredging and the Corresponding Adjustment

为解决当前疏浚船上电磁流量计测速过程中假设磁场均匀及无法实时标定的问题,本文提出一种新的磁场强度计算方法以克服应用过程中由上述假定所带来的局限性。该方法使用船上射线源密度计测得的含率及其变化率,分别作为计算电磁流量计磁场变化的输入变量,从而得到计算时变电磁场的磁场强度的两部分,据此对电磁流量计的测量流速进行修正。通过疏浚工程中实际测试,流速的平均计算误差能够降低为5.51%。本文方法为提高电磁流量计测量的准确性和可应用范围提供了实践基础。

At present,in the measurement of flow rate using an electromagnetic flowmeter in a dredger,it is assumed that the magnetic field is uniform and cannot be calibrated in real time.To solve this problem,a novel method to calculate the magnetic field intensity is proposed in this paper to overcome the limit brought by the above assumption when using the flowmeter.The solid phase fraction and its varying rate measured by means of a radiation source density meter are taken as input variables for computing the changes in magnetic field intensity by the electromagnetic flowmeter,respectively,thereby obtaining two parts of intensity of the time-varying electromagnetic field.On this basis,the measured flow rate is adjusted.Though an actual test in dredging engineering,the mean calculation error of flow rate was reduced to 5.51%.The proposed method provides a practical basis for improving the measurement accuracy when using the electromagnetic flowmeter and extending the appliable range.