Fuzzy TOPSIS optimization of heat transfer rate of magnetized radiative Casson nanofluid over a stretching sheet

Abstract Nanofluids provide an innovative solution for heat transfer and energy efficiency, making them highly beneficial across various industries. Their superior thermal conductivity, improved heat dissipation, and optimized energy efficiency makes them well-suited for applications in automotive cooling, industrial heat exchangers, electronics, renewable energy systems, hyperthermia cancer treatment, and targeted drug delivery. This study aims to determine a numerical solution for the flow of a magnetized radiative Casson nanofluid (CNF) composed of Aluminium Oxide (Al 2 O 3 )/Ethylene Glycol (C 2 H 6 O 2 ) and Copper oxide (CuO)/Ethylene Glycol (C 2 H 6 O 2 ) over an unsteady stretching, considering its wide range of applications. The objective of this work is to formulate a mathematical model of the physical flow problem and numerically solve the governing equations using shooting method via MATLAB. Furthermore, the most influential parameter for optimizing the rate of heat transfer is identified using Fuzzy Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The outcome of the influencing dimensionless parameters like unsteadiness parameter (S), stretching parameter (C), magnetic parameter (M), radiation parameter (Rd), Prandtl number (Pr), Eckert number (Ec) and heat generation parameter (He) are discussed via contour plots and tables. According to the study, an increase in radiation parameter (Rd), and heat generation parameter (He) result in increased temperatures. Additionally, the increase in the heat transfer coefficient is greater in CuO/C 2 H 6 O 2 nanofluid compared to Al 2 O 3 /C 2 H 6 O 2 nanofluid. Furthermore, Fuzzy TOPSIS analysis indicates that alternative A 20 represents the optimal best combination of physical parameters for enhancing the heat transfer rate for both Al 2 O 3 /C 2 H 6 O 2 and CuO/C 2 H 6 O 2 nanofluids.