Numerical investigation on effect of base fluids and hybrid nanofluid in forced convective heat transfer

• Hybrid nanofluids of CNTs and Al2O3 have been introduced in this study.
• Multiphase mixture model is employed to investigate convective heat transfer.
• Effect of base fluids on performance (water and ethylene glycol) is investigated.
• Combination of CNTs into Al2O3 provides significant enhancement in heat transfer.
• Ethylene Glycol base fluid gives better heat transfer enhancement than water.

Two-phase mixture model has been chosen to study forced convective heat transfer of nanofluid introducing a new concept of heat transfer enhancement in this article. Two different base fluids are individually employed to investigate the effect of base fluids on convective heat transfer mixing Al2O3 nanoparticles. The computational method has been successfully validated in case of Al2O3/water Nanofluids using available experimental data reported in the literature. The results show that Ethylene Glycol base fluid gives better heat transfer enhancement than that of water. Mixture of Al2O3 nanoparticles into CNTs/water Nanofluids is considered as a new concept of combined/hybrid nanofluids that can successfully enhance convective heat transfer. The computational model for CNTs/water nanofluid has been validated comparing the results with experimental data reported in literature. Then the validated method was used to simulate new concept of combined nanofluids. Combination of CNTs and Al2O3 nanoparticles into water base fluid tends to enhance the convective heat transfer performance significantly. It happens because CNTs nanofluid shows higher shear thinning behavior which causes the boundary layer thinner; in these regions the significant convective heat transfer enhancement takes place.