Optimization of Nusselt Number of Al2O3/Water Nanofluid Using Response Surface Methodology

This study has primarily aimed at the examination of the effect of flow rate, solid volume fraction and their interactions on the Nusselt number of Al2</sub>O3</sub>/water nanofluids. To investigate the main and interaction effects on the response, Response Surface Methodology (RSM) has been used based on the miscellaneous design. By using the analysis of variance (ANOVA) the significance of the model is tested. The responses to the Nusselt number of nanofluids are also estimated using second-order polynomial equations.  The results show that the Nusselt number increases with a higher amount of flow rate and solid volume fraction. According to the analysis of variance, the Reynolds number (A), first and second order of effects of volume fraction (B, B2</sup>), the interaction of Reynolds number and volume fraction (AB) is the most effective factors on the Nusselt number. Finally, the optimum condition of the process is predicted based on the RSM method. Having considered the optimum condition, the Nusselt numbers are compared with experimental data. The results show that there is a good agreement between the results of the proposed model and experimental data. Therefore, according to the results, the Nusselt number is precisely predictable in the model proposed by the Design Expert software.