Improved Heat Transfer Capabilities of Nanofluids-An Assessment Through CFD Analysis

Conventional fluids used in fission-based water-cooled nuclear reactors have lower heat transfer coefficients (HTCs) and thermal conductivity, which has led researchers to explore high-performance fluids that can enhance heat transfer in routine operation and prevent core meltdown in the case of accidents. It is important to investigate a wide range of fluids that can help designers improve thermal hydraulic characteristics, such as HTC, critical heat flux, and minimum departure from nucleate boiling ratio (MDNBR). In this study, the effectiveness of nanofluids in enhancing heat transfer parameters, including thermal conductivity and heat capacity, was investigated. Four different nanofluids (Al2O3-H2O, ZrO2-H2O, Ag-H2O, and Si-H2O) with pure water as the primary coolant in an HPR-1000 nuclear reactor were compared using computational methods. Due to computational limitations, only the flow channel among four fuel rods with the highest power density in the core was simulated using Eulerian computational fluid dynamics. The results of this study show that silver water (Ag-H2O) nanofluid outperformed other nanofluids and pure water. It had a higher average HTC and MDNBR, with a 67.15 % and 45.23 % improvement, respectively, compared to pure water. The fuel rod wall temperature was also reduced by 28.5 K with Ag-H2O compared to water. Comparison of current simulated results with literature data shows a good agreement. Conventional fluids used in fission-based water-cooled nuclear reactors have lower heat transfer coefficients and thermal conductivity, prompting researchers to explore high-performance fluids to enhance heat transfer and prevent core meltdown during accidents. It is crucial to investigate fluids that can improve thermal hydraulic characteristics, such as the heat transfer coefficient, critical heat flux (CHF), and minimum departure from nucleate boiling ratio (MDNBR). This study investigates the effectiveness of nanofluids in enhancing heat transfer parameters, including thermal conductivity and heat capacity. Results indicate that the silver water nanofluid outperformed the other nanofluids and pure water. The silver water nanofluid demonstrated a 67.15 % improvement in the average heat transfer coefficient and a 45.23 % enhancement in MDNBR compared to pure water. This study underscores the promise of nanofluids, particularly Ag-H2O, in enhancing the thermal performance and safety of water-cooled nuclear reactors. Future research should continue to explore various nanofluids and their applications to further optimize reactor design and operation, ensuring both efficiency and safety in nuclear energy production. image