Numerical assessment of the overall heat transfer and pressure drop performances of an aqueous ammonia base-nanofluids in rectangular microchannel heat sinks

In this paper, the thermal and hydrodynamic performances of an aqueous ammonia base-nanofluid (Al₂O₃NH₃(aqu)) cooled in a rectangular microchannel heat sink was numerically investigated. The range of Reynolds number used in the investigation were between 140-1400. In order to assess the performance of the system during the employment of the proposed nanofluid, H₂O and Al₂O₃-H₂O were also tested and their performances were compared to Al₂O₃-NH₃(aqu) performance in terms of thermal resistance and pressure drop. Results from the simulation showed that the proposed nanofluid outperformed pure water and slightly higher than Al₂O₃-H₂O in terms of thermal resistance (for Re = 1400, 0.0474, 0.0449 and 0.04647 ^oK/W for H₂O, Al₂O₃-H₂O and Al₂O₃NH3(aqu), respectively). However, it exceeds the performance of both pure water and Al₂O₃-H₂O in terms of pressure drop (for Re = 1400, 785288, 911217, 753591 Pa for H₂O, Al₂O₃-H₂O and Al₂O₃-NH3(aqu), respectively). The key findings from the current study may be used to attract more research about the proposed nanofluid to be used in the cooling process of microchannel heat sinks.