天然气水合物垂直管内流动特性的数值模拟

Numerical simulation of flow characteristics for natural gas hydrate in vertical tube

为了研究深水天然气水合物浆液开采管中水力提升的理想工况,对开采管中浆液的速度、体积分数、颗粒粒径和颗粒密度各参数划分12组,基于Fluent软件中欧拉双流体模型,采用SIMPLE算法和标准k-ε湍流模型,对水合物颗粒在管道中的黏度变化编制UDF,并对上述方案进行数值模拟,对比模拟得到水合物颗粒体积分数值与文献试验值,相对误差小于20%,该模型可行.结果表明:管道提升速度越大、浆液体积分数越小、颗粒粒径越小、颗粒密度越小对于水力输送越有利.因此,在满足系统安全性要求的同时考虑经济因素,对于直径300 mm的水力提升管,建议提升体积分数取20%,颗粒粒径取0. 01~0. 02 m,提升速度和颗粒密度分别控制在1. 4~1. 8 m·s^(-1),1 020~1 190 kg·m^(^(-3)),此时提升情况理想,系统具有一定的可靠性.

To investigate the ideal hydraulic lifting condition of deep-water gas hydrate slurry production pipeline,the parameters of slurry velocity,concentration,particle size and particle density in the production pipeline were divided into 12 groups.Based on the Euler two-fluid model in Fluent software,the SIMPLE algorithm and the standard k-εturbulence model,the hydrate particles in the pipeline were analyzed to compile UDF,and the proposed scheme was simulated and analyzed.The results show that the relative error between hydrate particle concentration and experimental data is less than 20%,which indicates that the model is feasible.With the increasing of lifting speed and with the decreasing of slurry concentration,particle size and particle density,the hydraulic transportation becomes more favorable.To meet the safety requirements of system and with the consideration of economic factors,the lifting concentration should be 20%with particle size of 0.01 0.02 m,and the lifting speed and the particle density should be controlled with the ranges of 1.4 1.8 m·s-1 and 1 020 1 190 kg·m-3,respectively.Under the proposed conditions,the ideal lifting situation can be obtained with reliable system.