Thermophysical properties, and figures-of-merit analyses of nanodiamond/CuO ionanofluids: Experimental and artificial neural network predictions

The nanodiamond/copper oxide (ND/CuO) nanoparticles were dispersed into 1-ethyl-3-methylimidazolium chloride [EMiM]Cl to create ionanofluids. The experiments were performed to analyse the thermophysical properties under particle volume loadings from 0.2 % to 1.0 %, and temperature ranging from 30 to 60 °C. Theoretical approach was made to understand the Figures-of-Merit (FoM) of the prepared ionanofluids, while they flow in a tube, and helical coil through the evaluated thermophysical properties. The lower thermal conductivity augment of 14.27 % was noticed at 0.2% vol. and larger thermal conductivity enhancement of 35.20 % was noticed at 1.0% vol. and at a temperature of 60 °C, against the base fluid. Moreover, the viscosity of 1.0% vol. of ionanofluid was enhanced by 61.66 % at a temperature of 30 °C, over the base fluid. The other properties like density was increased with an increase of volume loadings, and specific heat was decreased with an increase of volume loadings. The FoM results indicated that, all the prepared volume concentrations of ionanofluids flow in a tube was benefited fluid when the fluid operating temperature was exceeds to 35 °C, on the other side, the prepared ionanofluids flow in a helical coil was benefited fluid when its operating temperature was above 30 °C for 0.8 %, and 1.0% vol. loadings. The estimated thermophysical properties were also used as input and output data for an artificial neural network of Levenberg-Marquardt (LM) algorithm. It is noticed from the LM algorithm results, the predicted data is well agreed with an experimental data. For all the data, the correlation coefficient (R²) of thermal conductivity is 0.99283, viscosity is 0.9971, density is 0.99887, and specific heat is 0.99817, was observed, respectively.