深海竖管天然气水合物浆体输送特性OA

During the exploitation of natural gas hydrate in deep-sea vertical pipes,the flow regime transitions from a solid-liquid two-phase to a solid-liquid-gas three-phase state.The finite element method was employed to investigate the effects of inlet velocity,solid phase volume fraction,and par-ticle diameter on the transport characteristics of hydrate slurry.For the solid-liquid two-phase sys-tem,the pressure drop within the pipe initially increases gradually and then sharply with the increase in inlet velocity or solid phase concentration.At a solid phase volume fraction of 0.1,the pressure drop corresponding to an inlet velocity of 5 m/s is(950±50)Pa,which is a 58%increase compared to that at an inlet velocity of 2 m/s.At an inlet velocity of 2 m/s,the pressure drop at a solid phase vol-ume fraction of 0.3 is(1 000±100)Pa,representing a 66%increase compared to that at a volume fraction of 0.1.The introduction of gas increases the pressure drop within the pipe.At an inlet veloci-ty of 5 m/s and a solid phase volume fraction of 0.1,the pressure drop of the solid-liquid-gas three-phase system is(2 000±100)Pa,which is a 150%increase compared to the solid-liquid two-phase system.Moreover,as the solid phase particle diameter increases,the pressure drop of the three-phase flow within the pipe also increases.Controlling the inlet velocity to≤5 m/s,the solid phase volume fraction to≤0.3,and the hydrate particle diameter to≤0.5 mm can ensure sufficient kinetic energy supply within the vertical pipe while avoiding pipe blockage.