@

초록

Recent strategies for enhancing the thermal performance of shell-and-tube heat exchangers (STHEs) include fluid-based approaches, such as nanofluids, and geometric modifications. While recognizing the potential of advanced fluids, this study specifically focuses on improving the flow structure through geometric modification of the baffles. This study numerically examines the flow dynamics and thermal performance of an STHE incorporating trisection circumferential overlap helical baffles with a novel geometric configuration, specifically engineered to outperform conventional helical baffle designs. The new baffle incorporates a sawtooth-shaped edge composed of three individual sawtooth elements, each designed to be folded at a specified angle—features not found in existing baffle designs. Specifically, the sawtooth elements are arranged along the baffle edge and referred to as the first, second, and third sawtooth, progressing from the center to the shell periphery. The fold angle for the first sawtooth is either 0° or 15°, while the second and third sawteeth are folded at 0°, 15°, or 25°. Three-dimensional numerical simulations were performed to evaluate the influence of fold angles on the heat exchanger's thermal performance. The results show that the folded sawtooth design promotes strong vortices and turbulence, especially at larger fold angles, leading to significant improvements in heat transfer performance for both shell and tube sides. The heat exchanger with the largest fold angles exhibited the best performance, achieving a thermal performance factor of 1.106 at a shell-side inlet mass flow rate of 4.58 kg/s—representing a 10.6% enhancement over the plain baffle design and demonstrating the effectiveness of the proposed configuration.

키워드