Key Laboratory for Process Measurement and Control of Tianjin

Tianjin, China

Key Laboratory for Process Measurement and Control of Tianjin

Tianjin, China

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Xu Y.,Tianjin University | Xu Y.,Key Laboratory for Process Measurement and Control of Tianjin | Chen Y.,Tianjin University | Chen Y.,Key Laboratory for Process Measurement and Control of Tianjin | And 6 more authors.
Huagong Xuebao/CIESC Journal | Year: 2013

In order to investigate the over-reading prediction model of wet gas measurement using gas ultrasonic flow meter, a Z-shaped gas ultrasonic flow meter prototype was selected to analyze its measuring principle and mechanism of over-reading when metering wet gas flow. The laboratory tests were conducted in TJU adjustable medium-pressure wet gas test loop. The over-reading of Z-shaped gas ultrasonic flow meter was mainly related to the void fraction of the pipe under a uniform film assumption with annular flow. Meanwhile, the correlation between void fraction and over-reading was deduced. Five typical void fraction correlations of gas/liquid two-phase flow in horizontal circular pipe were selected to calculate the predicted value of over-reading. The most appropriate void fraction correlation for predicting over-reading of Z-shaped type gas ultrasonic flow meter was the Armand-Massina correlation. The over-reading prediction model based on this void fraction correlation had prediction relative errors ranging from -7.77% to 4.90%, with a standard uncertainty of 0.98% at 95% confidence interval. © All Rights Reserved.


Xu Y.,Tianjin University | Xu Y.,Key Laboratory for Process Measurement and Control of Tianjin | Wei J.,Tianjin University | Wei J.,Key Laboratory for Process Measurement and Control of Tianjin | And 3 more authors.
Natural Gas Industry | Year: 2015

In order to investigate how the pressure drop of stratified gas-liquid flow in horizontal circle pipes vary with flow parameters as well as its calculation method, we conducted experiments in the medium-pressure double-closed wet gas test loop in the Tianjin University. The experimental conditions were as follows: the working pressure from 0.2 to 0.8 MPa, the superficial gas velocity from 6 to 12 m·s-1, liquid mass fraction from 0 to 79.6%, the pipe diameter of DN50, and the pressure drop measuring distance of 3 m. Experimental results showed that pressure, gas velocity and liquid mass fraction affect the value of pressure drop, of which the liquid mass fraction is the key factor. The classical Chisholm correlation and ARS models taking the interfacial structure into account were chosen to predict the value of pressure drop with an average error of 25.89% and 11.56% and an uncertainty of 29.44% and 11.88% respectively. Further research on the Chisholm correlation through void fraction and friction coefficients indicated that the friction coefficient is another major factor which influences pressure drop. Finally, the Chisholm correlation was modified by use of the ratio λ (the two-phase friction factor) to λg (single phase friction factor), and the average error and uncertainty of the modified Chisholm correlation are 11.27% and 14.66% respectively. ©, 2015, Natural Gas Industry Journal Agency. All right reserved.

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