Simulation study of natural gas hydrate slurry flow characteristics in a high-pressure flow loop

• The flow characteristics of curved pipe were more complex and changeable, which benefitted hydrate particle accumulation. • The hydrate concentration gradient at the upper part of the pipeline section changed obviously. • The distribution of velocity distribution, hydrate volume fraction and pressure drop along the whole line changed obviously at the bend. • Sensitivity analysis by grey correlation showed that particle size was the most important factor affecting pressure drop. In this paper, Euler models suitable for hydrate slurry flow were established based on the particle dynamics theory. The results showed that the distribution of the velocity, particle concentration and turbulent kinetic energy in the curved pipe was more asymmetrical than that in the straight pipe due to the continuously changing flow field direction. The velocity, turbulent kinetic energy and particle concentration all increased with the increase of inlet velocity. The particle concentration gradient increased with the increase of the inlet particle volume fraction. The increase of particle size led to the increase of velocity heterogeneity and concentration gradient. The pressure drop factor along the pipeline increased with the increase of velocity, particle concentration and particle size, the pressure drop factor across the pipeline of 1.2 m/s was 78.08% higher than 0.5 m/s. It was found that the change of flow direction or the connection of different pipeline structure was the danger point of pipeline aggregation. Finally, based on the grey correlation analysis, the fluctuation of pressure drop factor was most affected by particle size, followed by particle concentration and velocity. The study provided reasonable suggestions and measures for practical pipeline transportation technology to avoid operational risks.