Ioan Pop

Natural convection of nanofluid inside a wavy cavity with a non-uniform heating: Entropy generation analysis

Purpose n n n n nThe main purpose of this numerical study is to study on entropy generation in natural convection of nanofluid in a wavy cavity using a single-phase nanofluid model. n n n n nDesign/methodology/approach n n n n nThe cavity is heated non-uniformly from the wavy wall and cooled from the right side while it is insulated from the horizontal walls. The physical domain of the problem is transformed into a rectangular geometry in the computational domain using an algebraic coordinate transformation by introducing new independent variables ξ and η. The governing dimensionless partial differential equations with corresponding initially and boundary conditions were numerically solved by the finite difference method of the second-order accuracy. The governing parameters are Rayleigh number (Ra = 1000-100000), Prandtl number (Pr = 6.82), solid volume fraction parameter of nanoparticles (φ = 0.0-0.05), aspect ratio parameter (A = 1), undulation number (κ = 1-3), wavy contraction ratio (b = 0.1-0.3) and dimensionless time (τ = 0-0.27). n n n n nFindings n n n n nIt is found that the average Bejan number is an increasing function of nanoparticle volume fraction and a decreasing function of the Rayleigh number, undulation number and wavy contraction ratio. Also, an insertion of nanoparticles leads to an attenuation of convective flow and enhancement of heat transfer. n n n n nOriginality n n n n nThe originality of this work is to analyze the entropy generation in natural convection within a wavy nanofluid cavity using single-phase nanofluid model. The results would benefit scientists and engineers to become familiar with the flow behaviour of such nanofluids, and will be a way to predict the properties of this flow for the possibility of using nanofluids in advanced nuclear systems, in industrial sectors including transportation, power generation, chemical sectors, ventilation, air-conditioning, etc.

Entropy generation of MHD nanofluid inside an inclined wavy cavity by lattice Boltzmann method

In this study, lattice Boltzmann method is applied in order to simulate the magnetohydrodynamic (MHD) natural convection heat transfer and entropy generation of CuO–water nanofluid inside an inclined wavy cavity. The left wavy wall is heated sinusoidal, while the right flat wall is kept at a constant temperature. The top and the bottom horizontal walls are smooth and insulated against heat and mass. The effects of active parameters such as solid volume fraction of nanoparticles, Rayleigh number, Hartmann number and inclination angles are examined on flow, heat transfer and entropy generation. The results proved that the heat transfer and entropy generation decline significantly with increasing Hartmann numbers, while those rise with increasing Rayleigh numbers. The results show that the effect of nanoparticles volume fraction on dimensionless Nusselt number and entropy generation is more pronounced at high Rayleigh number than at low Rayleigh number. Also the results indicate that the mean Nusselt number and total entropy generation changes with inclination angle, while the minimum values of

Axisymmetric rotational stagnation point flow impinging radially a permeable stretching/shrinking surface in a nanofluid using Tiwari and Das model

Nu_{text{m}}

MHD flow and heat transfer over a moving plate in a parallel stream with induced magnetic field

Num and S belong to

Unsteady flow and heat transfer past a permeable stretching/shrinking sheet in a nanofluid: A revised model with stability and regression analyses

theta = pi /3

Stability analysis on the flow and heat transfer of nanofluid past a stretching/shrinking cylinder with suction effect

θ=π/3 and 0, respectively.