Dynamic hydraulic models to study sedimentation in drinking water networks in detail

Drinking Water Engineering and Science

E. J. M.Blokker¹  I. W. M.Pothof¹ 

DOI  :  10.5194/dwes-5-87-2012

学科分类：工程和技术（综合）

来源: Copernicus Publications

【 摘 要 】

Sedimentation in drinking water networks can lead to discolourationcomplaints. A sufficient criterion to prevent sedimentation in the Dutchdrinking water networks is a daily maximum velocity of 0.25 m s⁻¹. Flushingexperiments have shown that this criterion is a sufficient condition for aclean network, but not a necessary condition. Drinking water networksinclude many locations with a maximum velocity well below 0.25 m s⁻¹ withoutaccumulated sediments. Other criteria need to be developed to predict whichlocations are susceptible to sedimentation and to prevent sedimentation infuture networks. More distinctive criteria are helpful to prioritiseflushing operations and to prevent water quality complaints.

The authors use three different numerical modelling approaches –quasi-steady, rigid column and water hammer – with a temporaldiscretisation of 1 s in order to assess the influence of unsteady flows onthe wall shear stress, causing resuspension of sediment particles. The modelpredictions are combined with results from flushing experiments in thedrinking water distribution system of Purmerend, the Netherlands. Thewaterhammer model does not result in essentially different flow distributionpatterns, compared to the rigid column and quasi-steady modelling approach.The extra information from the waterhammer model is a velocity oscillationof approximately 0.02 m s⁻¹ around the quasi-steady solution. The presence ofstagnation zones and multiple flow direction reversals seem to beinteresting new parameters to predict sediment accumulation, which areconsistent with the observed turbidity data and theoretical considerationson critical shear stresses.

【 授权许可】

Unknown