Pressure drop of the gas-liquid two-phase stratified flow in horizontal pipes: An experimental study

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.