Heat transfer enhancement and entropy generation minimization using CNTs suspended nanofluid upon a convectively warmed moving wedge: An optimal case study

Abstract

AbstractThis paper aims to examine the effects of singleand multi‐walled carbon nanotubes (CNTs) nanoparticles on heat transfer enhancement and inherent irreversibility in the boundary layer of water base nanoliquid flow over a convectively heated moving wedge with thermal radiation. Manipulation of the angle positioning towards the flow stream provides the opportunity for comparing physical aspects in the flow states, where three main geometries of the well‐known Falkner–Skan problem include: (i) the flat plat (named Blasius flow), (ii) the wedge, and (iii) the vertical plate (named Hiemenz stagnation flow) have been considered to present a comprehensive development of this significant problem. Applying suitable similarity constraints, the model partial differential equations are transformed into a set of nonlinear ordinary differential equations. Solutions are obtained analytically via optimal homotopy asymptotic method and numerically via shooting technique coupled with the Runge–Kutta–Fehlberg fourth–fifth scheme. The impacts of solid volume fraction of carbon nanoparticles along with other germane factors, such as wedge angle, velocity ratio parameter, Biot number, thermal radiation, and so forth on velocity and thermal profiles, Nusselt number, heat transfer enhancement, rate of entropy generation, and irreversibility ratio, are scrutinized via graphical simulations and discussed. Optimization of such entropy developments in the system was found to depend on geometrical (β), dynamical (λ), and thermophysical (Bi, NR, Ec, φ) parameters. The ultimate objective of reducing the energy loss and enhancing heat transference was obtained with the geometrical manipulation of a flat plate case (β = 0). Dynamically (λ = 1) were spotted to exert the best fluidity irrespective of obstacle shapes (wedge or plate) in its way. In thermophysical aspects, reducing the convective heating develops a favorable situation for attaining the optimal balance between energy loss and heat transfer. SWCNT/water could be the better choice with enhanced thermal transference ability and exerts minimal irreversibility to overshadow the influences of all the above‐mentioned factors. The SWCNT suspended nanofluid can provide 12%–64% heat transfer enhancement when compared with the multiwalled CNT nanofluid which ranges from over 11% to 58% heat transference rate.