COMPARISON OF MATHEMATICAL MODELS TO ESTIMATE THE THERMAL CONDUCTIVITY OF TiO 2-WATER BASED NANOFLUID A Review

Heat transfer is a desirable phenomenon in many industries such as in refrigeration, transportation, power generation, cell preservation, incubator, metallurgy and material processing, health services, etc. Different types of fluids like water, oil, ethylene glycol etc. are being used as a heat transfer medium. Water is a commonly used as working fluid for transfer of heat. Nanofluids are developed by adding nanosized particle(s) in existing fluid to improve the heat transfer rate. Thermal conductivity of the nanofluid is an important parameter in estimation of heat transfer rate. Different types of mathematical models were developed by various investigators to predict the thermal conductivity of the nanofluids. In this review paper, the theoretical and mathematical model(s) have been compared to predict the thermal conductivity of nanofluids. The experimental data have been collected from literature and compared with Maxwell model, Hamilton and Crosser model, Maxwell-Garnetts model, Pak Cho model, Timofeeva et al. model, Li and Peterson model, Bhattacharya et al. model, respectively in detail. It has been observed that the prediction with the help of the mathematical models is good when the value of volume fraction was less than 0.01.