Successive expansion and contraction of tubes (SECT) in a novel design of shell-and-tube heat exchanger: entropy generation analysis

• Published in: Journal of the Brazilian Society of Mechanical Sciences and Engineering 2024-05, Vol.46 (5), Article 267
• Main Authors: Avecilla, Fredy Rodrigo Barahona, Farajollahi, Amirhamzeh, Rostami, Mohsen, Yadav, Anupam, Flores, Juan José
• Format: Article
• Language: English
• Subjects: Effectiveness; Engineering; Entropy; Exergy; Fins; Fluid flow; Heat exchangers; Mechanical Engineering; Reduction; Reynolds number; Technical Paper; Tube heat exchangers; Tubes
• ISSN: 1678-5878; 1806-3691
• DOI: 10.1007/s40430-024-04850-w

Current research presents and investigates a novel design for the tubes of the shell-and-tube heat exchanger (STHE), by adding successive expansion and contraction of tubes (SECT). The main advantage of the expansion parts is to create a suitable location for adding thermal fins to the tubes. Therefore, in the current research, two new arrangements for the heat exchanger are proposed: the STHE with SECT, with/without thermal fins. Using validated numerical simulations, these two arrangements have been compared with the normal arrangement in terms of effectiveness and entropy generation rate. In this comparison, the Reynolds number of the shell/tubes has a constant/variable amount. The results show that the finned design increases the Nusselt number by 65.38% compared to the normal design. Additionally, it results in a 10.74% reduction in irreversibility and an 8.85% reduction in exergy loss. The STHE with the SECT and without fins and the STHE with SECT and fins increase the effectiveness to the relative amounts of 44% and 75% compared to the normal arrangement, respectively. Meanwhile, the arrangement with the SECT and fins, compared to the normal arrangement and the arrangement contains the SECT and without thermal fins, can reduce the entropy generation rate to a relative value of 27.5% and 38.3%, respectively.