关键词: 天然气水合物, 垂直管, 群体平衡模型, 多相流, 气泡聚并与破碎

Abstract: In the process of solid⁃state mining of deep⁃sea natural gas hydrates, when the balance of temperature and pressure is broken, the hydrate slurry in the production pipeline changes from liquid⁃solid (hydrate, seawater) two⁃phase to gas⁃liquid⁃solid (natural gas, hydrate,seawater). The three⁃phase flow of particles and seawater is the main research object in gas⁃liquid⁃solid three⁃phase flow. The Fluent simulation of the hydrate slurry flow in the vertical production pipe is performed using the CFD⁃PBM model, and the model is verified. The simulation results are in good agreement with the experimental values. The results show that the distribution of flow patterns simulated by PBM model is relatively uniform, and the size of bubbles in the flow process is mainly from small to large， the initial velocity of bubbles has a great influence on the hydraulic lifting speed of the pipeline， the turbulent kinetic energy in the slurry is 0.5 m2/s3. When the content is 0.3, bubbles will appear to be secondarily broken and broken. The bubble size distribution in the hydrate slurry system can be predicted by CFD⁃PBM to better predict the flow characteristics of the hydrate slurry after it is decomposed by natural gas.

Key words: Natural gas hydrate, Vertical tube, Population balance model, Multiphase flow, Bubble aggregation and crushing