Modelling and analysis of impact forces acting on elbow in gas-liquid slug flow

The impact forces caused by gas-liquid slug flow can lead to the vibration of process system or fatigue failure of pipe fittings. In this study, a piston-flow-model coupling with slug model is developed to calculate the impact forces, which can contribute to the structure design and flow assurance. An experiment installation is installed to study the characteristics of slug flow and validate the reliability of the model. The accuracy of this model is above 90% for the superficial velocity of gas below 2 m/s, whereas the average deviation is 29.2% for the cases of superficial velocity of gas above 2 m/s. The modified model addressing the liquid holdup agrees well with the experimental data, of which the average deviation is 6.25%.