Abstract

Nanofluids have recently been considered as one of the most popular working fluid in heat transfer and fluid mechanics. Accurate estimation of thermophysical properties of nanofluids is required for the investigation of their heat transfer performance. Thermal conductivity coefficient, convective heat transfer coefficient, and viscosity are some the most important thermophysical properties that directly influence on the application of nanofluids. The aim of the present chapter is to develop and validate artificial neural networks (ANNs) to estimate these thermophysical properties with acceptable accuracy. Some simple and easy measurable parameters including type of nanoparticle and base fluid, temperature and pressure, size and concentration of nanoparticles, etc. are used as independent variables of the ANN approaches. The predictive performance of the developed ANN approaches is validated with both experimental data and available empirical correlations. Various statistical indices including mean square errors (MSE), root mean square errors (RMSE), average absolute relative deviation percent (AARD%), and regression coefficient (R2) are used for numerical evaluation of accuracy of the developed ANN models. Results confirm that the developed ANN models can be regarded as a practical tool for studying the behavior of those industrial applications, which have nanofluids as operating fluid.

Highlights

  • Increasing price of fuels as well as hardening the environmental regulations/laws enforces the industrial processes to increase the efficiency of their consumed energy

  • Four different types of artificial neural networks include multilayer perceptron (MLP), cascade feedforward (CFF), radial basis function (RBF), and generalized regression (GR) neural networks that are used as artificial intelligent techniques for characterization of thermophysical properties of nanofluids

  • Correlation matrix analysis approves that size of nanoparticles, their molecular weight (Mw) and volume concentration fraction (Vf), critical pressure and temperature of the base fluids (Pc and Tc), their acentric factor (ω), Reynolds number (Re), and the wall condition are the most important factors that influence on the convective heat transfer coefficient (HTC) of nanofluids

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Summary

Introduction

Increasing price of fuels as well as hardening the environmental regulations/laws enforces the industrial processes to increase the efficiency of their consumed energy. Conducting research for modifying poor thermophysical properties of the Deterministic Artificial Intelligence traditional fluids confirmed that adding solid particles to the base fluids can improve their heat transfer properties [6]. It is possible to improve the thermophysical properties of the conventional fluids, and enhance their heat transfer ability by adding small amount of nano-sized solid particles [20]. Nanofluids have found high popularity due to their excellent ability in enhancement of heat transfer performances of various thermal systems during the recent years [16, 21, 22] In spite of such potential benefits, nanofluid technology is still limited for commercial use as there are no proven standardized techniques for accurate prediction of important heat transfer characteristics of nanofluids [23, 24]. The procedure of working of artificial neural networks and four different types of ANN are briefly explained

Artificial neural networks
Types of ANN model
Multilayer perceptron neural networks
Cascade feedforward neural networks
Radial basis function neural networks
Generalized regression neural networks
Training of artificial neural networks
Performance analyses of artificial neural networks
Characterization of properties of nanofluids by ANN approaches
Thermal conductivity coefficient
Experimental data
Development of ANN model
ANN model evaluation
Convective heat transfer coefficient
Experimental databank
Designing an ANN model
Evaluation of the performance of developed MLP model
ANN model development
Evaluation the ANN model performances
Conclusions
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