ADVANCES IN THE MODELLING OF VERTICAL HYDRAULIC TRANSPORT BY A CONTINUUM DESCRIPTION

摘要

In their 2011 CEDA paper, Van Wijk et.al. (2011) sketched the contours of a numerical model in which the transport process is modeled with an advection-dispersion equation for describing the vertical hydraulic transport process during deep sea mining. The proper choice of model components however was uncertain, hence an experimental program to gain more insight in the physics of vertical transport was introduced as well. In the course of 2012 we have learned a lot more about the transport process by conducting two experiments. The first experiment was a fluidization test with differently sized and shaped solids, which gave insight in the proper modeling of the advection terms in the transport equation. The second test comprised hydraulic transport of differently sized sediments through a flowloop, which gave much insight in both modeling the dispersion coefficient used in the transport equation as well as the transport process in total. This paper highlights the main advances in the modeling of vertical transport of relatively large solid particles by using a continuum description. We have restricted ourselves to the transport regime in which all material is homogeneously suspended. First a short overview of the model will be given. Then the fluidization tests and its implications will be discussed, followed by a description of the flowloop experiment and its implications. The final topic will be a comparison between the model and the flowloop measurements, which shows good agreement.