Experimental Study on Gas–Liquid Interface Evolution during Liquid Displaced by Gas of Mobile Pipeline

Abstract

The mobile pipeline is the most effective and reliable means for the emergency oil transfer task, which is temporarily laid on the field. After completing the task, the oil in the pipeline should be emptied before the mobile pipeline is removed. The oil in pipeline gradually displaced by the air is a main method of pipeline evacuation, which is the only choice of jet fuel pipeline. Due to the convection between gas and oil phases, the length of the oil–gas mixing section and the evolution of the oil–gas interface change with time. The evolution of the gas–liquid interface directly determines the different flow patterns of oil–gas two phases, which are very important for the mobile pipeline evacuation. In this paper, the characteristics of the gas–liquid interface evolution during the water displaced by air are studied, using the multi-phase pipeline experiment. Through the change of the gas–liquid interface in the initial stage of gas cap evacuation, it is found that the gas–liquid interface can be divided into smooth, wavy, and dispersed forms under different initial gas flow rates and different inclination angles. Slug phenomenon may occur in the process of gas-carrying liquid flow in the pipeline. The emergence of slug is mainly affected by hydraulic conditions and pipeline operating conditions. The liquid plug body is complex and unstable, and there will be a mutual transition between different liquid slug shapes. The increase of the inclination angle and gas phase velocity will accelerate the occurrence of liquid slug frequency.

Automatic Piston-Type Flow Standard Device Calibration System

“…To ensure the metering performance of the water meter, the automation control system sends commands to start the water pump for the water supply to exhaust the gas in the pipeline before the daily calibration of the water meter for the flow standard device. Meanwhile, vacuum operation is carried out for the tested meter [22]. For better automatic calibration of ultrasonic water meters, the piston-type flow standard device has been designed.…”

Experimental and OLGA Modeling Investigation for Slugging in Underwater Compressed Gas Energy Storage Systems

“…In Section comparative analysis of the entire process of slug flow formation in the experimen and OLGA models will be conducted. The figures presented in this section (i.e., Figu 23-26) have been compared with Figures 9,10,13,14,17,18,21 and 22, respectively. demonstrated that the OLGA software accurately replicates the formation of slug fl that before the slug flow occurs, the pressures at P1, P2, and P3 increase and present an irregular saw-tooth wave.…”

“…Additionally, the experimental apparatus used can impact the fluid, introducing errors in the experimental results. Given that liquid slug flow's formation, evolution, The occurrence of liquid accumulation in pipelines may generate local blockage, which elevates pressure and friction within the pipeline, ultimately leading to a more profound issue of slug flow [12][13][14]. The motion of slug flow in pipelines presents complex regimes that can engender erosion and wall damage, contributing to further corrosion and wear.…”