Investigation on void fraction of gas-liquid two-phase flow in horizontal pipe under fluctuating vibration

Accurate prediction of void fraction of gas-liquid two-phase flow under fluctuating vibration is crucial for the safe and stable operation of floating nuclear power plants. The void fraction characteristics of gas-liquid twophase flow in horizontal pipe under different vibration conditions are studied experimentally. The results showed that the void fraction of bubbly flow and intermittent flow varies considerably under fluctuating vibration, whereas changes in stratified flow and annular flow are less pronounced. Generally speaking, the void fraction first increases and then decreases with the increase of pipe diameter, while the increase of vibration frequency and amplitude cause a nonlinear variation in the void fraction. Evaluation of void fraction calculation models for stationary pipes reveals that existing models have significant prediction errors for bubbly flow and intermittent flow void fractions. By considering the effects of pipe diameter and vibration parameters, the Froude number of liquid phase is introduced to develop a void fraction calculation model for bubbly flow and intermittent flow. The Mean Absolute Relative Difference (MARD) of new established model is 10.66% and 12.06%. This significantly improved the prediction accuracy of the void fraction under fluctuating vibration.