Probing the hydrothermal performance of corrugated channels: A numerical scrutiny

Abstract

This work delves into probing the hydrothermal performance of corrugated channels of trapezoidal, sinusoidal and triangular geometries for the flow of a non-Newtonian viscoplastic fluid. The study systematically examines the effects of Bingham number (Bn), power-law index (n) and Reynolds number (Re) on the hydrothermal performance quantified by average Nusselt number ($\overline{\mathrm{Nu}}$), enhancement ratio (ER) and performance factor (PF). The recirculation zone size diminishes with increasing Bn and ceases to exist at higher Bn values. The value of $\overline{\mathrm{Nu}}$ decreases with an increase in n with the highest decrement of 14 % for the trapezoidal geometry as n increases from 0.5 to 1 at Re = 500. Over the entire range of Bn, trapezoidal geometry shows the best performance in terms of $\overline{\mathrm{Nu}}$ with 20 % increase over triangular geometry at n = 0.8 and Re = 500. The ER is evident predominantly within the lower range of Bn reaching a critical threshold (Bn_cr), which increases by almost 3.6 times with respect to the triangular geometry when trapezoidal geometry is used indicating better performance of trapezoidal geometry over that of a plain channel over a larger bandwidth of Bn. The variation in PF is intricately tied to the combined influence of geometrical and rheological parameters and the trapezoidal channel demonstrated superior performance.