Thermohydraulic performance study of the effect of winglet inserts and a corrugated wall in a rectangular channel

Abstract

This numerical study investigates the enhancement of heat transfer and pressure drop characteristics in rectangular channels with transverse corrugations and longitudinal winglet vortex generators. Numerical simulations cover a range of Reynolds numbers (Re) (5000–20000) using channels with uniform wall heat flux and fixed wavelength. The study evaluates the influence of geometrical parameters (corrugated channel amplitude and winglet length) on flow and temperature characteristics, average Nusselt number (Nu), and pressure drop. Corrugated channels alone create stationary transverse vortices that impede heat transfer. However, integrating winglet vortex generators introduces beneficial longitudinal vortices, disrupting stationary vortices, perturbing the thermal boundary layer, enhancing near-wall turbulence, and improving fluid mixing and heat transfer compared to smooth and corrugated channels. At Reynolds number (Re)20,000, corrugated channels with winglets exhibit 167.7 % and 61.8 % higher Nusselt numbers compared to smooth and corrugated channels, respectively. However, this enhanced heat transfer accompanies increased pressure drop. Both heat transfer and pressure drop rise with higher Reynolds numbers (Re), corrugation amplitude, and winglet length. This study provides insights into heat transfer mechanisms in corrugated channels and the potential for improvement through winglet vortex generators.

Keywords

• Heat transfer
• Pressure drop
• Corrugated channel
• Nusselt number (Nu)
• Winglet
• Reynolds numbers (Re)