Modeling and optimization of thermal conductivity of stabilized γ-Al2O3 /water nanofluid using response surface methodology (RSM)

Document Type : Research Paper

Author

Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran

Abstract

The present study estimates thermal conductivity ratio (KR) of stabilized γ-Al2O3 /water nanofluid by response surface methodology (RSM). This study was operated under experimental conditions with solid volume fractions of SVF=0.05–2%, and temperature of T=25–45 °C. Sedimentation visualization and dynamic light scattering (DLS) were performed to test the stability of nanofluids. The results of monitoring the stability of nanofluid with sedimentation visualization method showed that it was stable for at least 24 h. Different models were evaluated based on a series of quality indicators and charts. Some of the indicators that were investigated in this study include standard deviation (Std. Dev.), coefficient of determination (R2) and coefficient of variation (C.V). After checking the quality indicators and charts for different models, the quadratic model was selected as the optimal model. The values of Std. Dev, R2 and C. V for the quadratic model were 0.0241, 0.9785, and 1.87, respectively. Also, adjusted R2 and predicted R2 parameters of the quadratic model were equal to 0.9606 and 0.8776 respectively, which signifies the accuracy of the model. The residual plot, the normal probability plot, the Box-Cox plot and the predicted vs. actual plot also showed that quadratic model has a good accuracy, and is well capable of estimating the KR of the nanofluid. The most optimum KR is 1.485. At a temperature of 45 °C, this condition was achieved in samples at SVF=1.764%.

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Articles in Press, Accepted Manuscript
Available Online from 02 October 2024
  • Receive Date: 03 July 2024
  • Revise Date: 02 October 2024
  • Accept Date: 15 September 2024