基于双声道的低压超声气体流量计数据融合方法

A Data Fusion Method of Double-channel Ultrasonic Flowmeter Application in Low Pressure Gas

针对双声道的超声流量测量计测量低压中小管径流量时,超声波信号在低压气体中衰减大、信噪比低,导致某一声道的测量数据产生较大误差或错误,从而降低超声气体流量计测量的准确性和稳定性的问题,提出了一种时差法的双声道超声流量计数据融合方法。该方法首先对单一声道的时差数据进行粗大误差剔除和流量计算后,然后对数据进行预估处理获得流量状态,最后采用改进的卡尔曼融合方法计算管道内的平均流量,从而实现双声道气体超声流量计的数据融合和故障的判断。实验证明该方法的测量相对误差和重复性分别为-0.58%和0.21%。

The double-channel ultrasonic flow measurement is conventionally applied in low-pressure gas of the small and medium pipes.However,the error data and wrong data of one channel will be produced by the high attenuation and low signal-to-noise ratio when the ultrasonic signals travel in the low-pressure gas.So the accuracy and stability of ultrasonic flowmeter will be decreased.In order to solve these problems,a fusion method of double-channel ultrasonic flowmeter based on time-difference is proposed.Firstly,the gross errors of time-difference data are eliminated and flowrate is calculated in every channel.Then,the state of the flowrate is estimated by time-difference data.Finally,the improved Kalman data fusion is adopted to calculate the mean flowrate in pipe.The experimental results show that the measurement error is-0.58%and the repeatability is 0.21%.