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The main purpose of this paper is to define 2D numerical study and a sensitivity analysis of natural convection heat transfer and entropy generation of Al₂O₃-water nanofluid in a trapezoidal cavity, with considering of the presence of a constant axial magnetic field.

The effects of the three effective parameters, the Rayleigh number, Hartmann number (Ha) and also inclination angle on the heat transfer performance and entropy generation, are investigated using a finite volume approach. The sensitivity analysis of the effective parameters is done utilizing the response surface methodology.

The results obtained showed that the mean Nusselt number and total entropy generation increase with the Rayleigh number. Also, increasing the inclination angle reduces the mean Nusselt number (regardless of the magnetic field). In addition, it is found that the mean Nusselt number increases until Ha = 10 and then decreases by increasing of Ha number, regardless of the inclination angle. The sensitivity of the mean Nusselt number to the Ha number and inclination angle α is negative. It is concluded that to maximize the mean Nusselt number and minimize the entropy generation, simultaneously, the Ha and inclination angle must be 50° and 0°, respectively.

There is no published research in the literature about sensitivity analysis of magneto-hydrodynamic heat transfer and entropy generation in inclined trapezoidal cavity filled with nanofluid.

The purpose of this paper is to present the numerical solutions of surface radiation and combined natural convection heat transfer in a solar cavity receiver. The paper aims to discuss sundry issues that take place in the said model.

The numerical solutions are developed by means of second-order upwind scheme using the SIMPLE algorithm.

The effects of physical factors such as Rayleigh number (10⁴ ≤ Ra ≤ 10⁶), inclination angels of insulated walls (0º ≤ θ ≤ 10º) and the wall surface emissivity (0 ≤ ε ≤ 1) on natural convection-surface radiation heat transfer rate are analyzed. Impact of sundry parameters on flow quantities are discussed and displayed via graphs and tables. Stream lines and isothermal lines have also been drawn in the region of cavity. The numerical results reveal that increasing the Rayleigh number, wall surface emissivity and inclination angels of insulated walls in an open cavity enhances the mean total Nusselt number. The variations of the surface radiation and natural convection heat transfer mean Nusselt numbers are very small to the inclination angle of θ, while a significant change is noted for the case of Rayleigh number and emissivity.

To the best of authors’ knowledge, this model is reported for the first time.

The purpose of this paper is to study the optimal conditions of the mixed convection in a ventilated square cavity filled with Cu-water nanofluid using the Taguchi method. The paper aims to discuss diverse issues affecting the said model.

The numerical solutions of nonlinear coupled equations are developed by means of the Taguchi method. The Taguchi method is used as an effective way to optimize the design process engineering tests.

The governing equations are discretized using a finite volume method and solved with semi-implicit method for pressure linked equations (SIMPLE) algorithm. The effect of Richardson number (0.01-10), the volume fraction of nanofluid (0-5 per cent), distance of inlet port position from bottom wall of the cavity (0-0.9 H) and distance of outlet port position from top wall of the cavity (0-0.9 H) as effective parameters are analyzed across four levels. This analysis is done for fixed Grashof number 10⁴. The results show that the mean Nusselt number almost decreases by an increase in the Richardson number, volume fraction of nanofluid, position of the inlet port and position of the outlet port. It is found that the cavity with distance of inlet port position from bottom wall of the cavity 0 and distance of outlet port position from upper wall of the cavity 0.9 H at the Richardson number 0.01 and the volume fraction 3 per cent is the optimal design for heat transfer.

As far as the authors know, this model has been investigated for the first time.