Entropy generation and Bejan number analysis of Al2O3–Cu/H2O–C2H6O2 hybrid nanofluid flow in a generalized Bödewadt configuration with slip, suction and thermal radiation
Muhammad Rahman, Mustafa Turkyilmazoglu, Aqib AliPurpose
This study aims to examine entropy generation and Bejan number characteristics in the generalized Bödewadt flow of an Al2O3–Cu/H2O–C2H6O2 hybrid nanofluid over a stationary permeable disk. The proposed thermofluid formulation couples a generalized power-law outer vortex with a metal/oxide hybrid suspension in a 50:50 water–ethylene glycol base fluid, generalized momentum and thermal slip, suction/injection, thermal radiation and second-law irreversibility measures.
Design/methodology/approach
The similarity-reduced nonlinear boundary-value problem is solved using MATLAB bvp4c, and the numerical implementation is validated against established limiting solutions and through a domain and tolerance sensitivity study. Reduced skin-friction coefficients, the reduced Nusselt number, local and wall entropy-generation measures and the Bejan number are evaluated.
Findings
For the baseline suction regime, increasing −A from 2 to 4 raises Nured from 2.6894 to 4.0892 (about 52.0%) while simultaneously increasing Cf,red by about 34.9% and NG,wall by about 124.6%. Increasing the coupled slip parameters from α = β = 0.2 to 1 reduces Nured by about 56.0% and NG,wall by about 81.6%. Hybrid nanoparticle loading moderately improves heat transfer, whereas radiation increases the heat-transfer rate while redistributing thermal irreversibility across the boundary layer.
Originality/value
The results demonstrate that heat-transfer enhancement in generalized Bödewadt hybrid-nanofluid systems should be evaluated together with wall shear and entropy production rather than through the Nusselt number alone.