Experimental investigation on the effectiveness of MHTHS using different metal oxide-based nanofluids

In recent times, the mini heat sink is suggested for cooling the miniature components employed in several engineering applications. In the present work, the thermal performance of the mini hexagonal tube heat sink (MHTHS) was investigated experimentally. Nanofluids and deionized water (DIW) were made to flow through the hexagonal tube side and mini-passage side, respectively. For the preparation of different nanofluids of 0.01 volume fraction, DIW was considered to be a base fluid; Al₂O₃, CuO, and SiO₂ nanoparticles were reckoned to be the supporting materials. Experiments were run under two different conditions in order to ascertain the enhanced thermal performance of the MHTHS. They are as follows: (1) keeping the flow rate of hot DIW constant at 30 L h⁻¹ in the mini-passage side, the flow rates of nanofluids in the hexagonal tube were varied such as 15, 20, 25, 30, 35, 40, 45, and 50 L h⁻¹; (2) keeping the flow rate of nanofluids constant at 30 L h⁻¹ in the hexagonal tube side, the flow rates of hot DIW in the mini-passage side were varied such as 15, 20, 25, 30, 35, 40, 45, and 50 L h⁻¹. From the experimental results, it divulges that the heat transfer coefficient and effectiveness were found to be higher for Al₂O₃–DIW nanofluid, while comparing other nanofluids. A further improvement in the thermal performance of MHTHS could be achieved at higher volume flow rates of nanofluids in the hexagonal tube side and constant volume flow rate of hot DIW in the mini-passage side.