Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Analysis On The Effects Of Hopper Structure Geometry Of Trailing Suction Dredger
On The Sediment Loading Efficiency
Yuchi Hao12 , Jiaming Qu1 , Binliang Lin2, Qingbo Zhang1
1.CCCC National Engineering Research Center of Dredging Technology and Equipment, Shanghai, China, 2.Tsinghua University,Beijing, China.

ABSTRACTThe trailing suction hopper dredger(TSHD) completes the sedimentloading by the hopper system. The loading efficiency of the hopper
system is affected by the hopper geometry. The geometry of hopper
should be optimized according to the loading and deposition process inhopper, so as to improve the loading efficiency of the TSHD. In thispaper, based on the Navier-Stokes equations and the Camp method, athree-dimensional numerical mode of hopper system was presented,
and then verified by the real ship loading data of sediment withdifferent particle sizes, and then the influence of hopper geometry on
the loading of sediment is simulated and analyzed with the model. The
results show that, for the fine sediment (D50<100µm), the hopper
geometry should be wide and shallow for higher loading and smaller
overflow loss during loading. As the sediment particles become coarser,
the length of the hull should be used as much as possible to make thehopper and increase the length of hopper, so as to enhance the sedimentdeposition in loading. The relationship curve between overflow loss
and length depth ratio of the hopper is proposed, which provides areference for the design of hopper system.
KEY WORDS: Sediment; TSHD; hopper loading; overflow loss.
INTRODUCTION
The trailing sunction hopper dredge, which is named TSHD for short, isa kind of sea-going dredger, used in many project(Cees van Rhee,2001). When TSHD dredging, the suction pipes are put down to thesand surface under the water, and the hopper are loaded by pumping asand-water mixture from the dredge head.
The TSHD completes the sediment loading by the hopper system.
When the hopper full filled by dredging sediment, the loading process
will be continue until the inflow concentration near the overflow forhigher loading, during this time, sediment would be transported withthe overflow discharge overboard, which is called overflow loss. The
aim of TSHD dredging is to obtain the higher loading capacity and thelower overloss within a reasonable loading time, which is expressed byloading efficiency. So the loading efficiency has a very important
impact on the overall efficiency of dredging.
The loading efficiency of the hopper system is not only affected by thedredging concentration and flux of TSHD, but also affected by the3847

hopper geometry. Therefore, during the design and construction of a
new trailing suction hopper dredger, the geometry of hopper should be
optimized according to the loading and deposition process in hopper, so
as to improve the laoding efficiency of the TSHD.
The studies of the sediment loading in hopper system are as follows:
Theoretical researches about hopper sedimentation were establishedbased on Camp method(Camp, 1936, S.A.Miedema, 1996), Ooijens
improved the veloctiy and concentration in the loading process bylarge-scale model experiments(Sergio C,1999). Cee van Rheeestablished a two-dimensional CFD model of hopper system. In thesestudies, the Camp method can not simulate the effect of the geometryof hopper system on loading process.The two-dimensional CFD modelcannot simulate the hopper ’ s width, the position of inflow andoverflow(Miedema, 2007, 2008, 2009).
It is important to have knowledge of the sedimentation and scourcharacteristics of the dredged sediment during loading for a specifichopper system. In this paper, based on the Navier-Stokes equations andthe Camp method, a three-dimensional numerical mode of hopper
system was presented, and then verified by the real ship loading data of
sediment with different particle sizes, and then the influence of hopper
geometry on the loading of sediment is simulated and analyzed uesd themodel.The relationship curve between overflow loss and length depth
ratio of the hopper is proposed, which provides a reference for thedesign of hopper system.
METHODIn the hopper loading process, the mixture of water and sand enters thehopper through the pipeline at a certain inflow velocity. Although theenergy dissipation structure is set at the entrance, the kinetic energy of
inflow still exists, so the sediment will move in the hopper along withthe water flow. Therefore, the established model needs to describe andcalculate the movement of water and sediment.
Equations of water flow
For loading process of the hopper, the equations of water are: u   v  w0txyz(1)