Role of Sea-Salt Deposition on the Advances in Pool Boiling Heat Transfer

In the present work, the impact of varying the liquid coolant on transient pool boiling heat transfer was investigated using zirconium rods. Natural seawater is known to reduce the quenching time of the heated surface by facilitating an early transformation between film and transition boiling regimes. However, the mechanism of the sea-salt deposition on the heated surface is yet to be presented. As a result, an attempt has been made to fill this void. Five successive quenching experiments were performed using distilled water and natural seawater coolants at saturated temperature and atmospheric pressure. The natural seawater was collected from Doha Power Station along the coast of the State of Kuwait. The chemical composition, pH, total dissolved solids, and conductivity were examined. An experimental facility was built to conduct vertical quenching experiments. An embedded thermocouple in the rod was connected to the data acquisition system to record the temperature-time history during quenching. The quenching and pool boiling curves were analyzed by utilizing the temperature data. Subsequently, the surface morphology of the rods before and after quenching in each liquid coolant was characterized. The results explained the augmentation in heat transfer due to changes in the surface morphology caused by quenching in seawater coolant. The results revealed a remarkable boiling heat transfer enhancement, with minimum film boiling temperature (T min ) and critical heat flux (CHF) increase up to 25% and 93.6% in the fifth experiment, respectively. Based on the surface characterization results, a hypothesis on the mechanism of sea-salt deposition and its impact on destabilizing the vapor layer in film boiling regime was proposed. The findings of this study are anticipated to be beneficial in improving the safety margins for in-vessel retention of the fuel rods in nuclear power plants.