Abstract
Dredging is the process of excavation of sediment, usually carried out underwater, with the purpose of the collection of the excavated sediment, such as sand, and subsequently its disposition at another location. In order to be able to predict the performance of dredging equipment, such as dredging pumps and hoppers, a twophase numerical flow simulation method has been developed for conditions for which the volume fraction of the solid volume fraction (sand) is high.
The method is based on the equations for the twofluid model. The flow field is described by the conservation equations of mass and momentum for the solid phase (sand) and for the fluid phase (water), in combination with constitutive relations that describe the behaviour of the sandwater mixture, implemented in the commercial CFDcode Ansys CFX 14.0.
The viscosity of suspensions has been analysed experimentally, utilizing a concentric cylinder rheometer. In the experimental work, carried out with neutrally buoyant particles, parameters that determine the behaviour of the suspension have been varied, using the same particulate and liquid material for all experiments. The solid volume fraction, particle diameter, liquid viscosity, and shear rate, have been varied systematically.
An investigation has been carried out into a model for the particle pressure, required to model the formation of a particle bed when the volume fraction of the particles reaches its maximum obtainable value.
Dredging is often carried out by ships, storing the sediment in a large hold called a hopper. A sandwater mixture is taken from the bottom of the dredging site and pumped into the hopper. As an example of the application of the developed simulation method, the flow in a hopper during the filling process is considered. A parameter study has been carried out by varying the flow conditions at the inlet of the hopper: velocity at the inlet, solid volume fraction at the inlet and particle diameter of the incoming suspension. The results show how these parameters affect the filling curve of the hopper, defined as the total mass of sand present inside the hopper as function of time.
Original language  English 

Awarding Institution 

Supervisors/Advisors 

Award date  31 Aug 2016 
Place of Publication  Enschede 
Publisher  
Print ISBNs  9789036541671 
DOIs  
Publication status  Published  31 Aug 2016 
Keywords
 METIS317490
 IR100938
Fingerprint Dive into the research topics of 'Numerical simulation methods for sensephase dredging flows'. Together they form a unique fingerprint.
Cite this
Konijn, B. J. (2016). Numerical simulation methods for sensephase dredging flows. Enschede: Universiteit Twente. https://doi.org/10.3990/1.9789036541671