Numerical investigation and implementation of the Taguchi based entropy-ROV method for optimization of the operating and geometrical parameters during natural convection of hybrid nanofluid in annuli

Abstract

Numerical analyses have been carried out to investigate the effect of geometrical and operating parameters on heat and fluid flow of Cu–Al2O3/water Hybrid nanofluid inside annuli. The simulations are performed over a range of aspect ratio (200–500), orientation angle (30–90°), heat flux (2500W/m2-10,000W/m2), and volume fraction of nanoparticles (0–0.045) as controllable parameters. As a novelty, the study is further extended through Multi-response optimization using an entropy-based Range of Value (ROV) method to obtain optimum values of controllable parameters. The four output responses viz. heat transfer coefficient (h), Nusselt number (Nu), rate of mass flow (ṁ), and Reynolds number (Re) were computed and recorded using Taguchi's L16 orthogonal array. The obtained results illustrate that the heat transfer coefficient and mass flow rate increases with aspect ratio, inclination, heat flux, and nanoparticle concentration. The optimum grouping of the controllable factors which maximizes output responses are A4B4C4D4 (i.e.: Aspect ratio = 500, inclination = 90°, Heat flux = 10,000W/m2 and volume fraction of nanoparticles = 0.045). It is also inferred that the inclination has the maximum influence on the multi-performance characteristics followed by heat flux, aspect ratio, and volume fraction.