海底天然气水合物绞吸式开采水力输送机理与系统设计方法研究

Natural gas hydrate is considered as an important strategic resource, and this project aims at the research on the hydraulic transporting mechanism of natural gas hydrate cutter-suction mining as well as its design method. Firstly, theoretic and calculation analysis on the initial fluid performance parameters at the pipeline entrance is conducted so as to determine the value-obtaining method and the matching relations. Secondly, simulation calculation analysis on three dimensional fluid inside the pipeline is made to explore the changing law of fluid pressure field, fluid phase, fluid performance parameters, fluid temperature and the velocity distribution state as well as the concentration distribution law of each phase. With the obtained results, the predicting method for the altitude at critical point and the calculating methods for gravitational potential energy, kinetic energy and hydraulic loss of the fluid inside the pipeline are established. Thirdly, theoretic relationship between parameters of the initial fluid and those of pump head, power and hydraulic loss is analyzed so as to obtain both the design theory for gas hydrate hydraulic conveying system and the design method for optimal working parameters. Finally, by experimental research the simulation model is tested and verified. The research project will provide technical support for the cutter-suction mining method on submarine natural gas hydrate exploitation.

海底天然气水合物是一种重要的战略资源，本项目针对天然气水合物绞吸式开采水力输送机理与系统设计方法进行研究。首先，项目针对输送管道入口处流体初始特性参数进行理论和计算分析，研究其关键特性参数的取值方法和匹配关系。其次，建立输送管道内三维流场模拟计算方法，对输送管道内流体压力场的变化规律、流体的相变规律、各相流体特性参数的变化规律、各相流速的分布状态、各相浓度的分布规律和流体温度变化规律进行研究，得出天然气水合物发生相变时临界位置的确定方法，以及输送管道内流体重力势能、流体动能、流体水力损失的计算方法。然后，研究流体初始特性参数与水力输送系统扬程、功率、水力损失等工作参数之间的理论关系，建立天然气水合物水力输送系统设计理论和系统工作参数优化设计方法。最后，通过实验对仿真模型进行校验，完善天然气水合物水力输送的设计理论及系统优化设计方法。项目完成后将为我国海底天然气水合物开采提供理论支撑。

项目完成了针对天然气水合物绞吸式开采水力输送机理与系统设计方法的研究。首先，对输送管道入口处流体初始特性参数进行理论和计算分析，得到流体关键特性参数的取值方法和匹配关系。其次，对于管道输送系统中的多相管段，建立了水合物水力提升管道温压模型、水合物分解传质模型和管道多相流模型，分析相变过程中不同影响因素下管道流体温压、水合物颗粒物质的量与分解面位置的确定方法，以及水合物分解后不同参数变化下管道压力的损失规律。最后，通过建立深海采矿水力输送模型，研究了泵的空化特性以及流体初始特性参数与水力输送系统工作参数之间的理论关系，建立起天然气水合物水力输送系统设计理论和系统工作参数优化设计方法。相关研究与所取得的成果将对天然气水合物绞吸式开采水利输送系统各功能模块设计参数的选择与实际生产中工作参数的设置具有指导作用，同时也为系统整体实现高效化工作提供理论支撑。