1. College of Metrological and Measurement Engineering, China Jiliang University, Hangzhou, Zhejiang 310018, China
2. Zhejiang Cangnan Instrument Group Co., Ltd Cangnan,Cangnan, Zhejing 325800, China
Abstract：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%.
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2021, Vol. 42 
