|In recent years, research on the methods for heat transfer enhancement in heat exchangers has received great attention in order to cater for the growing needs of higher efficiencies in these devices. Corrugated surface geometry is one of the many suitable techniques to enhance the heat transfer in heat exchangers. When fluid flows in a corrugated channel, the flow becomes disturbed due to growing recirculation regions near the corrugated wall, which enhances the mixing of fluid as well as heat transfer. On the coolant side, the use of nanofluids, a liquid in which nanoparticles are added to a base fluid, can also enhance the heat transfer due to the improved thermal conductivity of the fluid.
The basic geometry of the present problem consists of corrugated channel which included velocity inlet condition and temperature of 300K, pressure outlet condition while slip velocity was ignored. Top and bottom walls for the test section are subjected to a constant heat flux of 10kW/m2 while adiabatic boundary condition is applied to the remaining walls. A numerical simulation is performed on thermal performance comparison of a corrugated channel with three corrugation profiles. Semicircle, triangular, and mixed are considered as corrugation profiles for corrugated walls of channel using nanoparticles volume fractions of Al2O3 and Reynolds number ranging from 0 to 0.06 and 10,000–30,000, respectively. Moreover, the results of triangular and mixed corrugated channel are compared with Semi-corrugated channel. Governing equations are discretized by using a finite volume method (FVM) and SIMPLE algorithm. The second order upwind scheme is applied and standard k-ε turbulent model with standard wall function is selected. The results showed that the Triangular channel has the average Nusselt number greater than 1.3 times of mixed shape (Semi-circular + Triangular) and 1.7 times of Semi-circular corrugated channel. Finally, it was found that among corrugated channels, the triangular channel provides the highest thermal performance followed by the mixed shape (Semi-circular + Triangular) and Semi-circular corrugated channels.