Numerical investigation of magnetic field on forced convection heat transfer and entropy generation in a microcnannel with trapezoidal ribs

In this study, the effects of adding trapezoidal ribs to microchannel on functionalized multi-walled nano-tubes/water nanofluid heat transfer are examined. The dimensionless slip coefficient (0-0.1), Reynolds number (50-400) and Hartmann number (0-20) are considered as independent variables and the heat transfer along with the entropy generation are considered as the output parameters. The simulation outcomes confirm that the addition of trapezoidal ribs, on the one hand, increases the heat transfer area and, on the other hand, intensifies the possibility of vortex formation. The presence of a vortex decreases the heat transfer potential and thus reduces the performance of the trapezoidal-wall microchannel compared to the base one. With increasing Reynolds number (Re), the probability of vortex formation intensifies, which in turn diminishes the positive effects of using trapezoidal ribs. However, it is found that, with increasing Hartmann number (Ha) and dimensionless slip coefficient (beta*), the vortex strength is weakened, and consequently heat transfer is improved. Based on numerical computations, it is found that at Re = 400, Ha = 0 and beta* = 0 and adding trapezoidal ribs to the base microchannel increases heat transfer by 11.12%.

Automated summary

The study examines the effects of adding trapezoidal ribs to microchannels on heat transfer with functionalized multi-walled nano-tubes/water nanofluid. Simulation results show that while the addition of trapezoidal ribs increases heat transfer area, it also intensifies the possibility of vortex formation. Vortex formation decreases heat transfer potential, especially with higher Reynolds numbers, but can be mitigated with higher Hartmann numbers and dimensionless slip coefficients.