A comparative study of aggregated and non-aggregated AA7075 nanoparticles in ethylene glycol-based nanofluid flow: an investigation of Hallcurrent and ion slip effects

The increasing relevance of nanofluids in modern engineering and technology has led to a remarkable surge in research focusing on their enhanced thermal properties, stability, and flow behavior under various physical conditions. Consequently, this study comprehensively examines how nanoparticle aggregation influences the thermal and hydrodynamic characteristics of AA7075-alloy nanoparticles dispersed in ethylene glycol (C2H6O2) base fluid. The assumed steady flowing fluid over a stretching sheet subjected to an externally applied magnetic field, Hall current and ion-slip effect is investigated. The concept of aggregation is incorporated into the effective transport properties through modified Maxwell, Bruggeman, and Krieger-Dougherty models. The governing boundary layer equations are reduced to ordinary differential form via similarity transformations and subsequently solved using a robust numerical scheme. The results reveal that non-aggregated nanoparticles exhibit higher temperature profiles and greater local Nusselt numbers owing to improved effective thermal conductivity, whereas aggregated suspensions increase effective viscosity, enhance dispersion stability, and damp transient thermal peaks. Quantitatively, a 9.3% reduction in drag force and a 5.0% enhancement in heat transfer are observed. Furthermore, Hall current and ion-slip parameters significantly influence both velocity and temperature fields, providing valuable insights for thermal management and process optimization applications.