Optimizing the hydrocyclone for ballast water treatment using computational fluid dynamics

Daniel Mccluskey,Arne Holdø

doi:10.1260/175095409788922310

Abstract

Environmental concern related to the transfer of Invasive Aquatic Species by ships ballast water has given rise to the development of a vast array of ballast water treatment systems. The complex environmental challenges and tight operational characteristics of marine vessels limits the scope of technologies used for Ballast Water Treatment. As a result few technologies have progressed beyond the Research and Development stage; however one of the most promising technologies for ship board use is the Cyclonic Separator, or Hydrocyclone. Despite the use of hydrocyclones in a wide variety of engineering applications they have yet to be successfully adapted towards the removal of suspended sediment and marine organisms from large volumes of ballast water. This paper details the operational characteristics of Ballast Water Hydrocyclones, employing empirical and experimental data to validate the use of a Detached Eddy Simulation (DES) turbulence model with Computational Fluid Dynamics simulations (CFD).

Highlights

80% of world trade is transported by shipping with a world shipping fleet of approximately 85,000 vessels with many of these ships using sea water as ballast
In this respect a number of additional simulations have been conducted in order to identify whether any improvement in the numerical modelling is the result of turbulence model selection, increased mesh density, or higher performance computing
Summary and Conclusion Three turbulence models have been applied to analyse the flow within a square profile duct with a 180°bend

Summary

Introduction

80% of world trade is transported by shipping with a world shipping fleet of approximately 85,000 vessels with many of these ships using sea water as ballast. The current practice of using water as ballast is essential to ensure the safe operation of vessels, and equates to approximately 3 to 5 billion tonnes of water transported by marine vessels annually [1]. This transfer of water around the world has an enormous biological effect on coastal and freshwater ecosystems, due in part, to the significant quantity of organisms and organic matter suspended in ballast water. The ready transport of debris and micro-organisms, coupled with the complex design of ballast tanks can result in large quantities of sediment being deposited within ballast tanks This can create a breeding ground in which certain organisms may flourish. Upon deballasting these organisms are deposited freely in coastal waters and at ports around the world and, providing the environment is suitable, they can establish themselves

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Discussion

Conclusion