Numerical investigation of the effect of fins on heat transfer enhancement of a laminar non-Newtonian nanofluid flow through a corrugated channel

In this study, the flow pattern and heat transfer enhancement of a non-Newtonian nanofluid in the presence of fins in a corrugated channel were numerically investigated. The fluid flow is in the hydraulically laminar regime, and the channel is under a constant heat flux. A set of case studies are conducted for the flow through the corrugated channel to analyze the effect of the main contributing factors; Reynolds number, the number of corrugation, the height of fin, the arrangement of fins (Cases A, B, and C), and the nanofluid volume fraction, on the flow field and the heat transfer characteristics as well. Comparing the results of the finned cases with different cases (without fins) indicates that implementing fins leads to a considerable change in the flow and temperature fields, resulting in the enhancement of heat transfer. Furthermore, results showed that using two corrugations in the channel provides a better heat transfer rate than other corrugation numbers. The results indicate that increasing the height of fins from 5 to 10 mm, changes the flow pattern and velocity distribution in the vicinity of the fins, and the maximum velocity occurs right on the head of the fins. Moreover, the results show that by increasing the height of fins, the pressure drop increases in the vicinity of fins. The bulk temperature in the vicinity of the corrugations is higher than in other regions, and by increasing the height of fins, the maximum bulk temperature decreases in these regions. Besides, increasing the nanofluid volume fraction and Reynolds number increases the local and mean Nusselt numbers. Moreover, it was found that the maximum value of Nu / Nu , at the highest Reynolds number (Re = 1000) occurs for case B with a fin height of Z = 7.5 mm. The results show that by optimizing the arrangement of fins, the mean Nusselt number can be improved 25.7 and 49.7%, compared to rectangular channel and smooth channel, respectively.