Effective thermal conductivity of carbon nanotube-based nanofluid

• CNT/water nanofluid thermal conductivity increases nonlinearly with CNT fraction.
• CNT/water nanofluid thermal conductivity enhancement is constant with temperature.
• A model with CNT aggregation for thermal conductivity is developed.
• The model gives lower and upper limits of nanofluid thermal conductivity.
• The aggregate-based model shows good agreement with experimental data.

The effective thermal conductivity of CNT/water nanofluid is measured with different CNT loadings (0.22–1 vol%) and temperatures (30–90 °C). The enhanced thermal conductivity increased nonlinearly with CNT concentrations while the ratios are almost constant with the rise of temperature. An aggregate-based model is proposed to predict the enhanced thermal conductivity of CNT-based nanofluid. The present model gives the lower and upper limits of CNT-based nanofluid with majority of the previous data fall within these bounds. CNT contact results in low-resistance heat conduction path which serves high thermal conductivity of nanofluid. The proposed model exhibits quite well an agreement with the experimental data and affords improved predictions for the enhanced thermal conductivity. The present study sheds light on the thermal conductivity mechanisms in CNT-based nanofluids with respect to CNT aggregate state in base fluids.

Figure optionsDownload as PowerPoint slide