Numerical analysis of thermohydraulic and exergetic performance in corrugated spiral tubes with diverse arc corrugation configurations

This study numerically analyzes the thermohydraulic performance and exergy destruction in a corrugated spiral tube, considering inward, outward, and combined inward-outward configurations versus smooth spiral tubes. It explores how key corrugation geometries like width, height, and pitch as well as flow parameter such as Dean number influence friction factor, Nusselt number, exergy efficiency, and thermal performance factor. The turbulence and thermal aspects of the flow physics are modeled by incorporating the pertinent governing equations, utilizing the SST k-ω turbulence model and Reynolds-Averaged Navier-Stokes (RANS) equations. The results demonstrated that introducing corrugated walls in various configurations enhances the Nusselt number within the spiral tube compared to its smooth counterpart. Nevertheless, this enhancement is accompanied by an increase in both friction factor and exergy destruction. Employing inward corrugations leads to a remarkable 53% surge in the Nusselt number when compared to the smooth tube. Elevating the corrugation height amplifies heat transfer and Nusselt numbers for all configurations, with the inward corrugation (IC) exhibiting the most substantial escalation. Additionally, a corrugation width of (w/D_h=0.1) engenders maximum thermal performance factor values across scenarios. Augmenting the corrugation pitch increases the Nusselt number due to greater heat transfer area, with the inward topology (IC) conferring maximal values. Although the Nusselt number rises with escalating Dean number, the thermal performance factor declines for all tubes owing to a disproportionately larger pressure drop increase. The outward corrugation tube (OC) sustains the highest performance factor across Dean numbers, while the inward-outward configuration (IOC) possesses the lowest.