On the application of detached eddy simulation turbulence modelling to hydrocyclonic separators for shipboard ballast water treatment

摘要

There is significant worldwide environmental concern related to the transportation ofInvasive Aquatic Species (IAS) by ships ballast water into non-native environments.This has given rise to the development of a vast array of technological ballast watertreatment systems. The complex environmental challenges and tight operationalcharacteristics of marine vessels limits the scope of the technologies used for BallastWater Treatment (BWT). As a result few technologies have progressed beyond theresearch and development stage; however one of the most promising technologiesfor ship board use is the cyclonic separator, or hydrocyclone. Despite the use ofhydrocyclones in a wide variety of engineering applications they have yet to besuccessfully adapted towards the removal of suspended sediment and marineorganisms from large volumes of ballast water.The following primary objectives of this study have been met:• Via critical review identify the technological solutions for treating ballast waterbest suited to onboard use.• Define the critical flow regimes evident within hydrocyclonic separators.• Establish a series of Computational Fluid Dynamics (CFD) simulations,evaluating standard turbulence models in order to determine the capacity forcommercial CFD to model hydrocyclonic flow.This study has detailed the operational characteristics of ballast water hydrocycloneswith the aim of enabling hydrocyclones to be optimised for individual shipconfigurations. Flow simulations have been conducted using CFD, and in particularthe Detached Eddy Simulation (DES) turbulence model. Finally the DES model isshown to be a legitimate turbulence model for hydrocyclonic flow regimes, validatedagainst empirical and experimental data.