Evaluating U/PD Ratio and Energy Efficiency in Heat Exchangers with Novel Baffles

Abstract

This research investigates a novel baffle configuration specifically designed to significantly reduce hydraulic resistance without sacrificing thermal capabilities. While traditional shell-and-tube heat exchangers (STHeX) are widely utilized, conventional segmental baffles frequently result in high pressure drops and the formation of thermal dead zones, directly compromising system efficiency. Existing studies have explored various modifications, yet a significant gap remains in achieving a streamlined flow that optimizes the trade-off between hydraulic resistance and thermal performance at higher mass flow rates. This research addresses this limitation by introducing trapezoidal baffles to fundamentally alter fluid dynamics, inducing a torsional flow pattern that eliminates stagnant zones and enhances mixing. Consequently, the proposed designs were numerically tested and optimized using three-dimensional Computational Fluid Dynamics (CFD) simulations to maximize the performance of the STHeX. The simulation results demonstrated that the Trapezoidal design offered superior hydraulic stability, maintaining pressure drops below 3200 Pa compared to over 4000 Pa in conventional segmental designs at peak flow rates (1.4 kg s⁻¹). Furthermore, this geometric modification resulted in a substantial improvement in the overall heat transfer coefficient per pressure drop (U/PD) ratio, achieving a peak efficiency of 0.9 W m⁻² K⁻¹ Pa⁻¹ compared to 0.7 W m⁻² K⁻¹ Pa⁻¹ for the conventional STHeX. This study concludes that modifying the baffle geometry into a trapezoidal profile is a vital strategy for drastically reducing hydraulic resistance while maintaining thermal performance, thereby significantly enhancing overall energy efficiency.