Parametric CFD Assessment of Al ₂ O ₃ –TiO ₂ Hybrid Nanofluid Cooling for a 15 Ah Lithium‐Ion Pou

This study presents a 28‐case computational fluid dynamics (CFD) parametric investigation of Al ₂ O ₃ /water and Al ₂ O ₃ –TiO ₂ /water hybrid nanofluid cooling for an LG Chem 15 Ah lithium‐ion pouch cell subjected to a prescribed steady thermal load of 277.5 W. The imposed load is used as a severe thermal‐stress condition for coolant comparison and is not interpreted as the electrochemical heat generated by the cell at a specific C‐rate. Four Reynolds numbers (Re = 2300–10,000) and three particle volume fractions (1%, 2%, and 4%) were examined in ANSYS Fluent. The Re = 2300 cases were solved as laminar, whereas Re = 4434, 7000, and 10,000 employed the realizable k–ε model with enhanced wall treatment. Nanofluid properties were estimated using a single‐phase effective‐property approach with Maxwell thermal conductivity and Brinkman viscosity correlations. The battery‐side thermal model was compared with FLIR thermography at 32 W under natural convection; this comparison supports the hotspot location and cell‐level temperature pattern but is not presented as forced‐convection nanofluid validation. Reynolds number remained the dominant control parameter. At Re = 2300, the 4% hybrid nanofluid reduced the maximum hotspot temperature by 8.1°C relative to water and increased the bulk‐temperature‐based heat‐transfer coefficient by ~13.1%. For the turbulent cases, all nanofluids produced PEC values below unity, while at Re = 2300 the PEC values were effectively unity (0.997–1.003). Above Re = 7000, the predicted temperature advantage of nanofluid addition decreased below 0.9°C. The results indicate that hybrid nanofluids primarily provide incremental hotspot reduction at low‐to‐moderate Reynolds numbers, whereas water remains the stronger thermal‐hydraulic baseline over the turbulent range.