Action law of structure shape and lifting efficiency of collecting cap

In order to obtain the action law of structure shape and lifting efficiency of collecting cap in the process of hydraulic collection of seabed granular minerals, the solid-liquid two-phase flow model of the hydraulic lifting process of the collecting cap with four different structure shapes was established, and the solid-liquid two-phase flow movement in the collecting cap during the process of hydraulic collection of granular minerals was numerically simulated. The flow field in collecting cap is turbulent. Euler-Euler model is used to calculate turbulence. The solid phase is granular mineral and the liquid phase is seawater. The distance between granular minerals and the bottom of the collecting cap is 100 mm. The velocity of the liquid phase at the inlet of the collecting cap is 2 m/s, and the initial velocity of the solid phase is 0 m/s. The hydraulic lifting process is considered to be over when the volume fraction of solid phase in the collecting cap is less than 2%. Firstly, the hydraulic lifting performance of different structure shape of collecting caps is studied when the diameter of granular minerals is 5 mm. Then, the diameter of granular minerals is set as 5 mm, 10 mm, 15 mm and 20 mm respectively, and the action law of granular minerals diameter and different structure shapes of collecting cap to lifting efficiency is studied. The results show that the hydraulic lifting efficiency of circular arc collecting cap (A cap) and arc roof inclined wall collecting cap (C cap) is higher than that of inclined roof vertical wall collecting cap (B cap) and arc roof vertical wall collecting cap (D cap). The hydraulic lifting efficiency of circular arc collecting cap (A cap) is the highest. The hydraulic lifting efficiency of A cap and C cap are insensitive to the change of granular mineral diameter. The hydraulic lifting efficiency of B cap and D cap are sensitive to the change of granular mineral diameter. As the lifting speed increases, the decreasing rate of lifting time gradually decreases, indicating that the lifting speed should not be too large to avoid excessive energy consumption in the lifting process when the lifting time is met.