Thermal and hydrodynamic performance of a novel passive mixer ‘wavering coiled flow inverter’

• Published in: Chemical engineering and processing 2019-07, Vol.141, p.107536, Article 107536
• Main Authors: Singh, Jogender, Montesinos-Castellanos, Alejandro, Nigam, Krishna Deo Prasad
• Format: Article
• Language: English
• Subjects: Compact heat exchangers; Curved tube; Process intensification; Wavering coiled flow inverter
• ISSN: 0255-2701; 1873-3204
• DOI: 10.1016/j.cep.2019.107536

[Display omitted] •Novel wavering coiled flow inverter (WCFI) is proposed for process intensification.•First study for developing flow heat transfer in coiled flow inverter (CFI) and WCFI.•WCFI offered up to 48% higher Nusselt number than helical coil at same pressure drop.•Further, the WCFI offered up to 18% higher Nusselt number than that of the CFI. This study explores the design of a novel passive mixer based on the concept of a coiled flow inverter (CFI) with an enhanced heat transfer efficiency. The proposed wavering coiled flow inverter (WCFI) was designed by inserting a 90° bend in halfway of the helical coils of equal arm lengths and wavering curvature radius. The hydrodynamics and thermal performance of the developed WCFI were than compared with helical coiled tube (HCT) and CFI with the same heat transfer areas (At = 0.062 m2 and 0.157 m2). Water was used as the working fluid in a range of Dean number from 8 to 1581. The designed WCFI, showed a 48% enhancement of the Nusselt number over an HCT with the same heat transfer area. Furthermore, the WCFI provided an 18% higher Nusselt number than the CFI due to the wavering curvature effects. Additionally, the friction factor data were practically comparable to that of the HCT. This study offers a preliminary investigation of the local and average heat transfer advantages of using a novel passive device WCFI. The present work may be significant, as it offers heat transfer augmentation via intensified geometrical design, without additional pressure drop.