Energy–efficient heat and momentum transport of a Cu–Al ₂ O ₃ –Ag/EG ternary hybrid nanofluid under unsteady squeezing in a rotating MHD channel

Efficient thermal management in compact devices requires working fluids and flow configurations that enhance heat-transfer density, mass diffusion, and rheological control. This study develops a continuum model for unsteady, three-dimensional squeezing flow of a Cu–Al2O3–Ag ternary hybrid nanofluid dispersed in ethylene glycol within a vertically rotating channel, incorporating Lorentz and Hall effects, Darcy–Forchheimer porous drag, nonlinear thermal radiation, viscous and Joule heating, Arrhenius kinetics, Soret diffusion, and a non-uniform heat source. Similarity transformations reduce the governing equations to a coupled nonlinear ODE system, solved via the Runge–Kutta–Fehlberg (RKF45) method to a tolerance of 10−6 and validated against two published benchmarks to four significant figures. Compared with a binary Cu–Al2O3/EG suspension, the ternary nanofluid increases the Nusselt number by about 18.6%, keeps wall shear stress within ±4% of the binary baseline, and limits the Sherwood number reduction to below 7%. Stronger squeezing reduces primary velocity and wall transport, while Hall current weakens the Lorentz force, enhancing both primary and secondary flows. These results indicate that the ternary hybrid nanofluid achieves superior thermal performance with minimal hydrodynamic penalty, making it suitable for microfluidic cooling, photovoltaic–hermal systems, rotating heat exchangers, and electromagnetic lubrication applications.