Numerical Modeling of OTEC Thermal Discharges in Coastal Waters

Abstract

Thermal discharge from industrial outfalls is categorized into two major classes based on their density. First class is the effluent that has a higher density than that of the ambient water body. The second class is the effluent that has a lower density than that of the ambient water body. Due to the effect of several factors such as tides, waves, winds, river discharges, thermal effluents etc., the mixing characteristics of OTEC (Ocean Thermal Energy Conversion) thermal plume is much complicated. In this study we try to identify the mixing and dispersion characteristics of coastal waters to consider their physical properties using a field observation and a three-dimensional numerical modeling with FVM (Finite Volume Method). A plume model and observed CTD data was used to predict the mixing behavior of thermal discharges in coastal waters. The elevation, current, temperature and salinity boundary conditions on the open boundary and thermal effluents at the specific boundary are considered in this study. Various turbulence models have been applied in the numerical model to assess the accuracy of turbulence models in predicting the effluent discharges in submerged outfalls. The model successfully reproduced well known the plume behavior in coastal waters. These works illustrate the challenging nature of OTEC environmental studies.lower density than that of the ambient water body. Due to the effect of several factors such as tides, waves, winds, river discharges, thermal effluents etc., the mixing characteristics of OTEC (Ocean Thermal Energy Conversion) thermal plume is much complicated. In this study we try to identify the mixing and dispersion characteristics of coastal waters to consider their physical properties using a field observation and a three-dimensional numerical modeling with FVM (Finite Volume Method). A plume model and observed CTD data was used to predict the mixing behavior of thermal discharges in coastal waters. The elevation, current, temperature and salinity boundary conditions on the open boundary and thermal effluents at the specific boundary are considered in this study. Various turbulence models have been applied in the numerical model to assess the accuracy of turbulence models in predicting the effluent discharges in submerged outfalls. The model successfully reproduced well known the plume behavior in coastal waters. These works illustrate the challenging nature of OTEC environmental studies.