Simulation of the Effect of Pipe Shape on Flow Rate in Air-Lifting Artificial Upwelling Based on CFD

Air lifting artificial upwelling is an important field of the artificial upwelling which brings the nutrient-rich deep sea water up to the surface and improves marine productivity via the buoyancy of air. Although there are plenty of studies have been conducted in this field, the effect of pipe shape in artificial upwelling have rarely been seriously considered. In this paper, applying computational fluid dynamics (CFD), a series of simulation was conducted on different shape of the pipe which is varying in size of top end and proportion of cone-frustum on pipe. And a dimensionless analysis was come up to value the efficiency. The simulation result indicates that firstly, pipe shape does have impact on flow rate of the artificial upwelling; secondly, the flow rate increases within enlarging the diameter of top end or proportion of cone-frustum in some degree, but after that it would work oppositely. It is believed that the nonlinear relationship hints that there is an optimal pipe shape to gain the peak flow rate in air lifting artificial upwelling and this study shall shed some light in building an upwelling device