Numerical modeling and multi-objective optimization of helically grooved tube geometry in shell-and-tube heat exchangers: A comprehensive analysis of heat transfer enhancement, turbulence characteristics, and pressure drop using COMSOL multiphysics

This study numerically investigates thermal performance enhancement in shell-and-tube heat exchangers using helical grooves. Through detailed simulations in COMSOL Multiphysics under laminar flow conditions, the geometry of the grooves-depth, width, helix angle, and number-was optimized to maximize heat transfer efficiency while minimizing pressure drop. Key performance metrics, including the Nusselt number, friction factor, and thermal performance factor (TPF), were evaluated and validated with experimental data. The results demonstrate that helical grooves significantly enhance heat transfer by inducing turbulence and increasing the effective surface area. The optimal configuration, featuring a helix angle of 40 degrees, a groove depth of 2 mm, and a pitch ratio of 24, achieved a 25 % increase in heat transfer efficiency compared to smooth tubes, with an acceptable pressure drop. This work highlights helical grooves as an effective passive enhancement technique for energy-intensive applications, such as power generation, chemical processing, and HVAC systems.