Simulation-based assessment of the thermal-hydraulic performance of titania-based nanofluids in a circular-mini-channel tube

Simulation-based assessment is performed here by using the single-phase model (S-PM) and the two-phase mixture model (T-PMM). The models are used to investigate the heat transfer performance of TiO₂/water nanofluids inside a circular tube with a diameter of 1.09 mm and a length of 306 mm. Reynolds numbers are varied from 600 to 2100, while the nano-particle concentration is 1.0, 2.0, 3.5 and 5.0 vol.%. Higher friction factor (f) and convective heat transfer coefficient (h) were observed for titania-based nanofluids compared to those of the base fluid (water). Heat transfer performance of the nanofluid increases as the nanoparticle concentration is increased. Likewise, the augmentation in pressure drop increases with nano-particle concentration. The highest enhancement in the Nusselt number of 14.81% was observed for nanoparticles with a concentration of 5 vol.% at the Reynolds number of about 1500.