Investigation On Pressure Drop Characteristic Of Low Liquid Loading Gas-Liquid Two-Phase Flow In Wet Gas Pipelines

Low liquid loading two-phase flow, which occurs frequently in wet gas transmission pipelines, is one of the typical occurrences of two-phase flow. In natural gas transmission, even when the gas input is in single phase state, liquid may be formed in the pipelines due to retrograde condensation as a result of pressure drop. The presence of traces of liquid causes considerable increase in pressure drop along the pipeline. Accurate pressure gradient prediction is vital in selection of the right pipe size and material, and pressure boosting facilities. At the same time, the liquid holdup is important for determining the pigging frequency and receiving facilities, it has important significance in corrosion occurrence, hydrate or paraffin deposition problem. Therefore, the main focus of this thesis is to investigate the pressure drop characteristics of low liquid loading gas-liquid two-flow in the transportation pipelines of wet gas.The applicable range of interface models and flow pattern of gas-liquid two-flow are discussed through the literature research. The governing equation is established based on the gas-liquid momentum equation. The corresponding closure correlations are used to calculate the parameters of the governing equation. The droplet entrainment and interfacial friction factor which have a great impact on the pressure drop are investigated. Laboratory data were used to compare the existing closure relationships of droplet entrainment fraction and interfacial friction factor. The effect of droplet entrainment on pressure drop was discussed from sensitivity analysis.The major objective of this study is, therefore, to compare the existing six kinds of models with four groups of data from different sources from the point of view of superficial gas and liquid velocity and droplet entrainment, and analysis the errors of different models.