A prediction model for the critical liquid-carrying velocity of gas–liquid stratified flow in micro-tilting line pipes with low liquid contents

摘要

Wet gas can form liquid loading at the lower line pipe sections, so the transportation efficiency will be impacted and the line pipes will be corroded and even blocked. Therefore, to accurately predict the critical liquid-carrying velocity of gas is of great significance to preventing the liquid loading in wet gas line pipes. In view of the gas–liquid two-phase stratified flow in micro-tilting line pipes with low liquid content, this paper newly established a critical liquid-carrying velocity prediction model considering droplet entrainment according to the momentum balance equation of a gas–liquid two-phase flow and the closure relationship of a new gas–liquid interface shape. Then, based on the experimental data, the new model, FLAT model, ARS model, double-circle model and MARS model were verified and their prediction results were compared. Finally, the new model was applied to analyze the effects of pipe dip, operational pressure, liquid density and gas component on the critical liquid-carrying velocity and critical liquid content of natural gas–water and natural gas–60% glycerine with water stratified flow in a micro-tilting line pipe. And the following research results were obtained. First, with the increase of pipe dip and liquid density, the critical liquid-carrying velocity increases continuously and the critical liquid content decreases gradually. Second, with the increase of operational pressure and heavy component content, the critical liquid-carrying velocity decreases continuously and the critical liquid content increases gradually. In conclusion, the new model is higher in prediction accuracy and its prediction result is better accordant with the experimental value, so it can be used to predict the critical liquid-carrying velocity in wet gas line pipes.