چكيده به لاتين
In this study, flow and heat transfer through a porous heat sink which is cooled by a impinging jet, have been studied numerically. At the first (first problem), the Darcy- Brinckman- Forchemier equation for fluid flow and thermal equilibrium equation for heat transfer are governed. Then in the next section (second problem) with considering of magnetic field and viscous dissipation, the first problem is developed. In the next step, for solving the partial differential equations, some similarity variables are defined and finally, non-linear ordinary differential equations will be obtained and by using bvp4c solver numerically will be solved. The effects of different parameters such as Darcy number, Reynolds number, aspect ratio, Eckert number, Hartman number, porosity, dimensionless distance from the axis, form drag coefficient, volume fraction of nanofluid and cooling fluid distribution in the inlet of the heat sink are investigated. The results presents that nanofluid volume fraction, Reynolds number, Darcy number rise and porosity, Eckert number, aspect ratio decrease would increase the heat transfer rate of hot wall. In addition, the Hartman number depended on porosity would have different effect on heat transfer rate. In the other word, in the low porosity would have decreasing effect and in the high porosity would have increasing effect on the heat transfer rate. It should mentioned that in thermal aspect, using of negative slope velocity distribution is the best one. Nanofluid volume fraction augmentation will increase the velocity and non-dimension temperature profile. Form drag coefficient does not have appreciable effect on velocity and non-dimension temperature profile. Porosity has low influence on fluid flow filed but has tangible effect on temperature. Magnetig field has great effect on flow field but in opposition of porosity does not have appreciable effect on temperature. Due to considering viscous dissipation in energy equation, temperature distribution contours will increase and the temperature gradient specific in the far region of axissemetric axis will decrease.
