A review on the impacts of dissolved salts in seawater on heat transfer, flow behaviors and fouling

After the Fukushima accident, the potential of seawater containing diverse dissolved salts and organisms as an alternative coolant source for offshore nuclear power plants (NPPs) has garnered significant attention. This study provides a detailed comparison of the heat transfer performance and flow behavior of seawater and pure water. Initially, the thermophysical properties of seawater are outlined based on its composition and salinity levels. Parameters such as the heat transfer coefficient and critical heat flux are analyzed through numerical simulation and experimental research. Given the coupled nature of flow and heat transfer, the study delves into the flow behaviors of seawater, examining velocity distribution, bubble characteristics, pressure drop, and flow instability. The phases of bubble growth and departure are explored to elucidate the differences in bubble dynamics between seawater and pure water. Variations in bubble size distribution and coalescence mechanism reveal unique two-phase flow patterns in seawater. Finally, fouling behaviors in heat exchangers using seawater are classified and investigated, offering insights into the subsequent stages of the fouling process, microscale events, and their influences on heating surfaces. This review identifies a research gap concerning the impacts of dissolved salts on the thermal hydraulics of seawater, proposing several challenges for future research based on current findings.