A comparative analysis of nanoparticle aggregation and non-aggregation in a nanofluid flow over a cylinder influenced by prescribed surface temperature

Purpose: Nanofluids enhance heat transfer due to the inclusion of nanoparticles, but the exact reasons remain debated. Limited nanoscale experiments hinder understanding. To investigate the thermal effects of nanoparticles, understanding nanoparticle aggregation kinetics is crucial. Nanoparticles have applications in various industrial fields. This study compares the effects of nanoparticle aggregation and non-aggregation in a nanofluid flow influenced by an inclined magnetic field around an expanding or shrinking cylinder, incorporating the generalized Fourier law with a prescribed surface temperature. Design/methodology/approach: The model problem is solved numerically with the bvp4c finite difference collocation method, known for its accuracy. Findings: Graphs and tables illustrate how key factors affect velocity and thermal fields. The results revealed that for stretching flows, fluid velocity increases with higher nanoparticle concentrations and velocity slip, while shrinking flows show opposite trends. The drag force decreases with rising Hartmann numbers and nanoparticle volume fraction, irrespective of aggregation. Surface drag is more affected by aggregation than non-aggregation in both shrinking and expanding cases. The study also validates the proposed model. Originality/value: Before this, numerous attempts discussed aggregation and non-aggregation separately on a deforming cylinder. Nevertheless, no study has yet assessed the impact of a slanted magnetic field on comparing the effects of nanoparticle aggregation versus non-aggregation in nanoliquid flow over a deformable or shrinking cylinder. This seems to be the first attempt to compare nanoparticle aggregation versus non-aggregation in nanoliquid flow.