Effect of Spiral Inlet Geometric Parameters on the Performance of Hydrocyclones Used for In Situ Desanding and Natural Gas Hydrate Recovery in the Subsea

[Image: see text] The inlet structure of hydrocyclones has great impact on performance. In this paper, the effects of spiral inlet geometric parameters on the flow field characteristics and separation performance were investigated by CFD. Numerical results show that the pitch has the largest influence, followed by the heads, the turns, and the steady flow cone. With the increase of the steady flow cone angle, the turbulence intensity increases. The efficiency, pressure drop, tangential velocity, sand volume fraction at the spigot, and natural gas hydrate (NGH) volume fraction at the vortex finder decrease, when the pitch increases. With the increase of the number of heads and turns, the efficiency, pressure drop, tangential velocity, the NGH volume fraction at the vortex finder, and the sand volume fraction at the spigot increase. The efficiency and pressure drop of hydrocyclones with the optimal parameters are 90% and 0.05 MPa, respectively. Therefore, the performance of the NGH hydrocyclone can be improved by increasing the inlet pitch and the number of spiral heads and inlet spiral turns. The results provide theoretical guidance for the engineering design of NGH in situ separators.