Experimental investigation on heat transfer and pressure drop of Al2O3-base oil nanofluid in a helically coiled tube and effect of turbulator on the thermal performance of shell and tube heat exchanger

These days With respect to the high importance of energy concept, limitation of natural resources, regulation of environmental issues, and global warming, heat transfer systemschr(chr('39')39chr('39')) applications get more attention. In the present paper, the experimental effect of Nano-fluid and turbulator on the heat transfer and pressure drop is investigated. AL2O3-SN300 base oil as nanofluid with weight percentage of 0.05, 0.1, 0.3, and 0.5 are used. To investigate the effect of heat transfer, a steel rotational turbulator was inserted inside the heat exchanger. The experiments were conducted under a constant heat flow rate of 3950 W/m2 and 5280 W/m2 and temperatures of 30, 40, 50, and 60 C. The whole process has been repeated for eight different mass flow rates under the laminar flow condition. The results show a higher heat transfer coefficient of Nano-fluid than the base fluid. Increasing the weight percentage of Nano-fluid caused enhancement of pressure drop in the system. The heat transfer coefficient directly relates to the mass flow rate and increases by raising the Reynolds number. The results reveal that using a turbulator enhances the heat transfer significantly. The experimental results are in reasonable agreement with theory by less than 10 percent mean error.