4683 × 10−9, 1/Da = 2.8605 × 106, T (ambient) = 293 K. First of all,

we found the steady state for the flow. After finding the steady state, the values of the local Nusselt number for various values of the modified Rayleigh number ( ) have been calculated for different values of permeability of the medium containing glass spheres of 1 mm in diameter. These values are compared with the values found by some research (experimentally and theoretically) for the steady state. Cheng and Minkowycz [1] studied free convection about a vertical flat plate embedded in a porous medium for SYN-117 supplier steady-state flow. They used the boundary layer approximations to get the similarity solution for the problem and found the value of the local Nusselt number Nu = 0.444 RaK0.5. Evans and Plumb [2] experimentally investigated the natural convection about a vertical plate embedded in a medium composed of

glass beads with diameters ranging from 0.85 to 1.68 mm. Their experimental data were in good agreement with those of the theory of Cheng and Minkowycz [1] as shown in Figure 2. Hsu [4] and Kim and Vafai [5] showed that, in the case of an isothermal wall, the local Nussel number Nu = C × RaK0.5; here, C is a constant and depends upon the porous media and the fluid. These results for the steady-state natural convection of water in porous media have also been verified by various authors and can be found in the book by Neild and Bejan [9]. From our JPH203 nmr Calculations given in Tables 1 and 2, it is clear that for various values of modified Rayleigh numbers, the selleck value of Nu/RaK0.5 is almost constant, and the value of this constant

is ≈ 0.44. This implies that our results are in good agreement with those of the work done previously. Figure 2 Theoretical data from Cheng and Minkowycz [[1]] and experimental data from Evans and Plumb [[2]] . Graph adapted from Neild and Bejan [9]. Results and discussion Computations have been done for the vertical plate with a length of 40 mm placed in the copper powder (porous medium). The ambient temperature is considered to be 293 K. The value of Forchheimer coefficient (F) is taken as 0.55. Calculations have been Phospholipase D1 done for six different types of nanofluids, viz. Al2O3 + H2O, TiO2 + H2O, CuO + H2O, Al2O3 + ethylene glycol (EG), TiO2 + EG, and CuO + EG, with different nanoparticle concentration and particle diameter in the temperature range of 293 to 324 K. Base fluid thermophysical properties are taken at the intermediate temperature, i.e., 308 K, to get a good correlation between thermal conductivity and viscosity data used by Corcione [14]. Heat transfer enhancement at steady state using nanofluids To find the steady state of flow and heat transfer, the average Nusselt number and average skin friction coefficients are plotted with time, as show in Figure 3. From Figure 3a,b, it is observed that the average Nusselt number and average skin friction coefficient decrease very fast initially, but after a certain time, these values become constant.