A COMPREHENSIVE AND COMPARATIVE EXPERIMENTAL ANALYSIS ON THERMAL CONDUCTIVITY OF TiO 2 -CaCO 3 /WATER HYBRID NANOFLUID: PROPOSING NEW CORRELATION AND ARTIFICIAL NEURAL NETWORK OPTIMIZATION

In this study, the thermal conductivity of TiO2-CaCO3/water hybrid nanofluid, which was prepared with five different concentrations and two-step method, was experimentally investigated. Thermal conductivity measurements were made using the KD2 Pro device at a temperature range from 10 degrees C to 60 degrees C. Using experimental data, a mathematical correlation and an artificial neural network model was developed in order to predict thermal conductivity depending on concentration and temperature. In the feed-forward back-propagation artificial neural network with 10 neurons in its hidden layer, the multilayer perceptron model was preferred. While the value of the coefficient of determination R for the proposed new mathematical correlation was 0.9999, it was obtained as 0.99913 for the artificial neural network model. The average error rate was calculated as 0.005% for the mathematical model and -0.02% for the artificial neural network.