A combination method for metering gas–liquid two-phase flows of low liquid loading applying ultrasonic and Coriolis flowmeters

• A novel combination measurement method for metering gas–liquid two-phase flows was developed.
• Ultrasonic and Coriolis flowmeters were allocated in series for horizontal stratified and annular flows.
• The apparent readings were modelled to derive the individual gas and liquid mass flowrate.
• Experimental data within the range of 0.04≤x≤0.65, 0.03≤X≤1.10 and 0.2 MPa≤P≤0.5 MPa was presented.
• Two combination measurement models were developed and verified through the experimental data.

A new method for measuring the individual mass flowrate of gas–liquid two-phase flow of low liquid loading was proposed based on the combination of ultrasonic and Coriolis flowmeters. The ultrasonic flowmeter and Coriolis flowmeter were allocated in series along a horizontal flowline under stratified and annular flow regimes. A coupling model was obtained by combining two sub-models developed based on the two measurement principles respectively. The combination model was verified through experimental data and it has been demonstrated that (1) with the coupling model taking the apparent gas volumetric flowrate from the ultrasonic flowmeter and mass flowrate from the Coriolis flowmeter as inputs employed, the root-mean-square errors of the calculated gas and liquid mass flowrates are 3.09% and 12.78%, respectively, within the range of 0.15≤x≤0.65, 0.03≤X≤0.45 and 0.2 MPa≤P≤0.5 MPa; (2) it is a possible way to develop a coupling model by employing the apparent density from the Coriolis flowmeter instead of the mass flowrate to extend the application range of the combination measurement method and the root-mean-square errors of the calculated gas and liquid mass flowrate are 2.59% and 4.38%, respectively, within the range of 0.04≤x≤0.15 at P=0.2 MPa.