Investigation of different theoretical models in predicting the thermal conductivity of nanofluids containing CuO nanoparticles

In this research, the effect of temperature and volume fraction of nanoparticles on the thermal conductivity coefficient of CuO nanofluid hasbeeninvestigaed experimentally.Then, theobtainedresultshave been compared with the values obtained from the classic used models for estimating the thermal conductivity coefficient of mixturessuch as Maxwell, Hamilton-Crosser, Jeffrey, Timofiva and Sundar. Copper oxide nanoparticles (CuO) after preparation, in volume fractions of ۰.۰۵% to ۰.۸%, are colloidal in water base fluid. The thermal conductivity coefficient of nanofluid in the temperature range of ۲۷۸ to ۳۲۳ K has been experimentally obtained to investigate the effect of temperature. In this research, the hot wire method is used to measure the thermal conductivity coefficient of nanofluid using KD۲-Pro (decagon) thermal analyzer. The results show that with increasing temperature and volume fraction, the thermal conductivity of nanofluid increases. Also, the effect of increasing temperature is more evident in higher volume fractions, and the increase in thermal conductivity coefficient has a non-linear relationship with increasing temperature and volume fraction. From the comparison of the experimental results with the models used to estimate the thermal conductivity coefficient, it shows a huge difference between the results, and this difference increases with the increase in volume fraction and temperature, and it shows that these models have the necessary validity for These nanofluids do not know the thermal behavior.

Keywords:

nanofluid , thermal conductivity coefficient , volume fraction , theoretical models