Flow rate measurement of low GVF gas-liquid two-phase flow with a V-Cone meter

Accurate online measurement of the liquid flow rate in a low GVF gas-liquid two-phase flow is of great importance for engineering and science. In the present study, a cost-effective metering method is developed on the basis of a V-Cone meter. Experiments are carried out in a horizontal test section and the fluids are air and water with GVF of 0–12.2%. The flow characteristics of the V-Cone throttle device with low GVF gas-liquid two-phase flow passing through are investigated. Experiments show that the V-Cone throttle device can modulate the flow pattern and the gas presence in a liquid flow can accelerate the development of the flow downstream of the cone. To correct the gas-induced liquid flow rate prediction error, a dimensionless parameter termed the two-phase mass flow coefficient is proposed. Experimental results indicate that the coefficient is dependent on the gas densiometric Froude number, the liquid densiometric Froude number and the gas-to-liquid density ratio, and the consequent correlation is obtained by data fitting. Besides, the permanent pressure loss of the V-Cone is investigated and a prediction correlation for the two-phase pressure loss is proposed. Finally, by incorporating the two-phase mass flow correlation and the pressure loss correlation, a metering method for the liquid flow rate in a low GVF gas-liquid two-phase flow is developed. The relative error of the liquid mass flow rate predicted by the method is less than ±4.0% at the confidence level of 97.5%. The newly developed metering method provides a high-accuracy as well as cost-effective measurement technology for the industry.