Heat transfer study on concentric tube heat exchanger using TiO2–water based nanofluid

In the present study, the heat-transfer characteristics of TiO2–water nanofluids as a coolant in concentric tube heat exchanger are presented. The heat exchanger is fabricated from copper concentric inner tube with length 1000 mm. The nanofluids are the mixture of water as base fluid and TiO2 particles in nano-range. The results obtained from the nanofluids cooling in concentric tube heat exchanger are compared with those from base fluids as coolant. Effects of inlet flow rate of hot fluids, Reynold's number and composition of nanofluids on concentric tube heat exchanger are considered. It is observed that the average heat transfer rates for nanofluids as a cooling media are higher than those for the water which is also used as cooling media, and this increases with concentration of nanofluid composition. The results of this study have technological importance for the efficient design of concentric tube heat exchanger to enhance cooling performance at low heat flux cooling systems.