A Model-Based Transit-Time Ultrasonic Gas Flowrate Measurement Method

Based on the transit-time ultrasonic gas flowrate measurement principle, a new model-based time-of-flight (TOF) measurement method is proposed. The proposed TOF measurement method includes two parts, the signal preprocessing and the model-fitting. Zero-phase filtering and independent component analysis with reference (ICA-R) are used to realize the signal preprocessing. The least-squares algorithm is used to implement the model-fitting and hence to obtain the TOF. A new single-acoustic-path ultrasonic gas flowmeter prototype with the inner diameter of 100 mm is developed and experiments are carried out to test the performance of the prototype. Experimental results show that the proposed signal preprocessing can effectively correct the distorted/noise-polluted measurement signal. In addition, the proposed model-based TOF measurement method is effective and can implement TOF measurement with higher repeatability and low standard deviation. For the gas flowrate ranges from 5 to 50 m(3)/h, the repeatability error of gas flowrate measurement is less than 1.99% and the maximum relative error of flowrate measurement is less than 3.27%. For the gas flowrate ranges from 50 to 500 m(3)/h, the repeatability error of gas flowrate measurement is less than 0.51% and the maximum relative error of flowrate measurement is less than 1.43%.