A numerical study on the thermal response of biodegradable ferrous oxide/aluminium oxide nanofluid flow past an unsteady contracting permeable cylinder: A comparative analysis

Esters that are considered natural come from renewable sources like vegetable or animal oils or other bio-based materials. Due to natural esters' great biodegradability, lack of toxicity, and high flash point, their use in industrial applications has been expanding quickly in recent years. The current study, thus numerically investigates an unsteady laminar flow and heat transfer of biodegradable nanofluids past over a shrinking cylinder of time dependent radius. Natural Ester (NE) is used as the base fluids, and two nanoparticles such as Fe₃O₄ (ferrous oxide) and Al₂O₃ (aluminium oxide) are used to create different combinations of nanofluids. The unsteady Navier-Stokes equations are used to model it, and similarity solutions are introduced to solve the problem. A MATLAB built-in package BVP4c has been employed to tackle the problem. The physical behavior of the solution has been explored in terms of parametric analysis and graphical demonstration and the validation of present solutions is reported by the comparative benchmark with already available results in a limiting sense. Our findings demonstrate that Fe₃O₄ biodegradable nanofluids are capable of carrying and dispersing thermal energy more effectively, resulting in improved heat transfer rates compared to Al₂O₃ biodegradable nanofluids.