Numerical Modeling of Pollutant Dispersal from Watercraft Exhaust Systems

by KISHORE, ARAVIND

The goal of this thesis is to analyze Carbon Monoxide (CO) dispersal in water. Watercraft exhaust systems issue gaseous products of combustion, of which Carbon Monoxide is a toxic component, from under the hull of the watercraft into the water. The aim of the present study is to simulate CO dispersal using Computational Fluid Dynamics (CFD). Due to the similarity in physical configuration to the watercraft exhaust system, the canonical problem of a single Jet In Cross Flow (JICF) is chosen as a validation case. Simulation of the JICF affords insight into the adequacy of the computational methodology before the methodology can be extended to simulate the present problem. Watercraft exhaust systems include dual exhaust ports, and hence, the methodology used to simulate the single jet is extended to a dual-jet system. Results show a pronounced interaction of the flow structures developed in the flow field. Further, the jets in the dual-jet configuration do not penetrate the cross flow to the extent that the single jet does. This phenomenon will prove important in the design and control of systems where multiple jets are used for optimum mixing. The watercraft exhaust system is simulated and the results presented show that the prevailing large-scale flow structures affect the dispersal of CO. Based on these results, three ways of mitigating CO dispersal are proposed.