Comparative analysis of tube designs in heat exchangers: A numerical simulation study for enhanced thermal-flow efficiency, "optimizing wavy tubes bundle geometries for enhanced heat transfer in underwater applications"

Abstract

With the growing challenges of heat transfer in marine vehicles and underwater power stations, the demand for an effective tube heat exchanger has surged. Numerical simulations were conducted on the constant, laminar flow of an incompressible viscous fluid inside a wavy tube while keeping the wall temperature consistent. The laminar flow was modeled in two dimensions using ANSYS FLUENT 19.2. For the water fluid model, an integrated algorithm was used to link the pressure and velocity fields. Primarily examined were circular tube banks organized in a staggered arrangement. The primary equations were approached via a finite volume method based on a combined technique. This study aimed to evaluate and contrast the heat exchange and flow traits of four distinct tube designs: asteroid (ASTB), hypotrochoid (HTB), Wavy edge circle (WCTB), and mixed bundle (MBT). The influence of tube design on a heat exchanger’s thermal-flow efficiency was measured across Reynolds numbers ranging from 100 to 400. The results indicated an improved Colburn factor and a decrease in both the friction factor and tube performance for all scenarios examined. Three key metrics determined the optimal tube design: the performance evaluation criterion (PEC), the global performance criterion (GPC), and the average Nusselt number (Nu). Regardless of the Reynolds number, the conventional HC had the least efficient PEC, while the STB registered the peak PEC value. The highest GPC was attained with the STB. Nu values remained relatively consistent for ASTB, HTB, WCTB, and MBT. In evaluating the average Nusselt number, the ASTB outperformed the STB (92–106% higher), HTB (36–48% higher), WCTB (21–32% higher), and MBT (57–64% higher).