Microreactor-Enabled One-Step High-Throughput Flow Synthesis of Titanium Dioxide Nanofluids for Efficient Pool Boiling Thermal Management of Power Electronics

Phase change cooling serves as an effective thermal management solution for high heat flux applications such as 5G base stations and data centers, and the incorporation of nanofluids could further enhance its cooling performance. However, the practical utilization of nanofluids in pool boiling systems strongly relies on their high stability and high-throughput production capability. Furthermore, the underlying mechanisms responsible for the enhanced pool boiling heat transfer in nanofluids, particularly the alterations in the bubble behavior, remain inadequately understood. This study proposes a high-throughput microreactor for the one-step continuous preparation of titanium dioxide (TiO₂) nanofluid, achieving a production rate of 2 L/h. The synthesized TiO₂ nanofluid exhibits a narrow size distribution (average size: 28 nm) and remains stable within 40 days at 20 and 80 °C. The boiling heat transfer experiment demonstrates a 17% enhancement in critical heat flux (CHF) and a 39% increase in maximum heat transfer coefficient (HTC) accompanied by a 10.3 °C reduction in wall temperature. The 5 h operation test shows no significant increase in the temperature of the silica chip. Furthermore, the enhanced mechanisms are analyzed based on bubble behavior, spot-like deposition, and microlayer formation. The experimental results show an enhancement in nucleation site density and a simultaneous reduction in bubble volume. Moreover, the increase in the microlayer area caused by nanofluids significantly enhances heat transfer. These findings not only provide possibilities for industrial-scale nanofluid synthesis but also offer valuable insights into the application of nanofluids in phase change cooling for electronic devices.