ScholarWorks@경상국립대학교

초록

In this paper, the large eddy simulation of turbulence in coaxial cylinders determines the influences of slit structure on flow characteristics and heat transfer behavior. The cross-sections of slits are trapezoid, rectangle and ellipse respectively. The field synergy principle and entropy generation are utilized to comment on the heat transfer properties. The results demonstrate that slit shape influences the heat transfer capacity remarkably. The trapezoid and rectangle slit models show backflow in the slit region, while ellipse slit model has no backflow, thus being expected to result in the fluid exchange is more sufficient. In terms of field synergy principle, the ellipse slit model possesses the smallest field synergy angle under different Reynolds numbers which reveals the finest collaboration relationship of velocity with the temperature fields. The thermodynamic analysis indicates that thermal entropy generation has been promoted as a major contributor to total entropy generation, and the entropy production value of the ellipse slit model is small, leading to the energy utilization rate is better than other models. The finest heat transfer efficiency is found with the ellipse slit model for given Reynolds number range.

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