Numerical investigation of thermal and entropy generation characteristics in a sinusoidal corrugated channel under the influence of sinusoidal wall temperature

The corrugated channels play a vital role in many engineering applications, such as electronic cooling and heat exchanger devices; thus, forced convection heat transfer and entropy generation within the corrugated channels are important subjects to investigate. This study numerically investigated the laminar forced convection heat transfer and entropy generation of water flow within a sinusoidal corrugated channel. The channel walls were subjected to sinusoidal wall temperature heating while varying the wave parameters. The finite element method had been employed to solve the governing equation, and the simulation results were conducted for Reynolds number 5 ≤ Re ≤ 500, dimensionless wall temperature wavelength 0.25 ≤ λth ≤ 2.25, and Prandtl number Pr = 6.93. The main findings were depicted in terms of Nusselt number, skin friction coefficient, heat transfer effectiveness, total entropy generation, and Bejan number contours, as well as the results being compared with the results of uniform heating. In addition, the results demonstrated that sinusoidal heating significantly improved heat transfer compared to uniform heating for λth < 1.75 and all ranges of Reynolds number, while a critical Reynolds number was found, where the uniform heating showed a higher heat rate compared to non-uniform heating at λth ≥ 1.75 . Besides that, it is found that the sinusoidal wall temperature has lower entropy generation than uniform heating, except with λth = 0.25. This investigation recommends that sinusoidal wall temperature heating is more effective in heat transfer than uniform heating by 7.5, 2.78, 1.9, 1.52, and 1.34 factors at λth = 0.25,  0.75,  1.25,  1.75 and 2.25, respectively.