Research on numerical simulation of initial process of sediment discharge from deep-sea mining vehicle

With the continuous advancement of deep-sea mining technology, increasing attention has been given to the potential impact of sediment plumes on marine ecosystems. This study employs a Euler-Euler model to numerically simulate the process of sediment discharge during the initial stage of deep-sea mining vehicle operations. It explores the effects of factors such as initial discharge velocity, discharge volume concentration, and particle size range on the diffusion and evolution of sediments. By analyzing the characteristic length of the sediment jet, the results show that the numerical simulations are consistent with theoretical expectations. The findings indicate that as discharge velocity increases (from 0.5 m/s to 4 m/s), the horizontal diffusion distance of sediment particles increases by approximately 255 %, while the diffusion width only increases by around 56 %. When the initial discharge volume concentration increases (from 1 % to 7 %), the horizontal distance at which sediment particles first impact the seabed decreases, and the impact angle becomes more vertical. In terms of particle size, coarse particles (105-139 mu m) tend to settle significantly near the nozzle during discharge, with their concentration reaching the maximum discharge volume concentration around 3 %. These results provide valuable insights that can better understand the environmental consequences of deep-sea mining activities.