Thermo-hydraulic and thermal stress performance of a shell-and-tube heat exchanger under varying tube-wall thickness: Coupled CFD–FEA investigation

Abstract Shell-and-tube heat exchangers (STHE) are widely used in industries because of their efficiency, simplicity, and high-pressure drop capability. However, their tubes are prone to failure modes such as erosion, thermal fatigue, vibration, pressure impact, and fouling, which over time affect their operational performance and increase the cost of maintenance, repair, or replacement. The tube wall thickness is a critical design parameter in shell-and-tube heat exchangers, influencing the thermal performance, hydraulic behaviour, and structural integrity. This study investigates the coupled effects of tube thickness on the overall heat transfer coefficient (HTC), tube-side pressure drop, and thermal stress using SOLIDWORKS Flow Simulation and structural analysis tools (ver. 2025). The geometry was modeled in a three-dimensional (3D) model with two passes and water as the working fluid. The SOLIDWORKS Flow Simulation tool (ver. 2025) was used to perform the computational fluid dynamics (CFD) simulation on the model domains, adopting the k-ɛ turbulence model and structural analysis tools. A parametric analysis was conducted by varying the tube thickness while maintaining constant operating conditions. In the simulation, the tube thickness was increased from 0.5 to 2.0 mm. The results showed that at a higher tube thickness, there was a reduction in the overall heat transfer coefficient and thermal stress, whereas a substantial increase in the pressure drop at the tube side of the shell-and-tube heat exchanger was observed. When the tube thickness increased from 0.5 to 2.0 mm, the HTC from 839 to 682.9 W/m ², amounting to an 18.6% in HTC, whereas the maximum von Mises stress decreased by approximately 14.9% when the tube-wall thickness increases from 0.5 mm to 2.0 mm. Consequently, increasing the tube wall thickness from 0.5 to 2.0 mm resulted in a substantial increase in pressure drop from 65.3 to 3352 Pa, corresponding to an increase of approximately 50.33% (51.3-fold), and the maximum von Mises stress decreased from approximately 1.575×10 8 Pa at 0.5 mm wall thickness to 1.34×10 8 Pa at 2.0 mm, representing an overall reduction of approximately 14.9%. This indicates that the pressure drop is considerably more sensitive to the tube wall thickness than the thermal performance parameters. This finding helps in adopting the appropriate tube thickness in the design of shell-and-tube heat exchangers.