Three-level homogeneous model for the study of heat transfer mechanism in metallic nanofluids

To explain heat conduction mechanism in nanofluids, different existing models have been analysed, but none of these can predict exact variation of thermal conductivity with volume concentration. In present study, it is found that the static and dynamic contributions of nanoparticles in the base fluid are responsible for its conductivity. Unfortunately, these both aspects have not been included in any of the existing model. We have modified the Xuan model including effect of shape and size of nanoparticles (static contribution) and allocation of nanoparticles, temperature, junction layer, congregate pattern, and Brownian diffusion (dynamic contribution) to propose a new model which can predict the exact mechanism of thermal conductivity of nfs. We have tested the proposed model to compute the thermal conductivity of Al2O3, ZnO, Ag, CuO, Co3O4 and Fe2O3 based nanofluids at different volume concentrations. Computed results using our proposed model are in very good agreement with experimental data.

Automated summary

To explain heat conduction mechanism in nanofluids, existing models have been analyzed but none of them accurately predict the variation of thermal conductivity with volume concentration. In this study, the static and dynamic contributions of nanoparticles in the base fluid are found to be responsible for its conductivity. A new model, which incorporates the effects of nanoparticle shape, size, allocation, temperature, junction layer, congregate pattern, and Brownian diffusion, is proposed to predict the exact mechanism of thermal conductivity of nanofluids. The proposed model shows good agreement with experimental data when applied to various nanofluids at different volume concentrations.