연구홍보포털

논문 초록 (Abstract)

A modified local ventilation system using vortex flows with vanes is proposed to enhance ventilation performance. The effect of the vanes on the stability of vortex generation, its structure, and ventilation performance was experimentally investigated using particle image velocimetry measurements. The mean velocity vectors and vorticity contours with and without vanes were compared for Qex = 0.129 m^3/s at Vs = 1.73 m/s to investigate the effect of vanes on the vortex characteristics. The flow structures, including the mean velocity field and vortex core size, were very similar with and without the vanes. However, distinct differences were found in the vortex characteristics related to vortex stability, including turbulent kinetic energy, circulation, swirl ratio, and vortex center distances. The normalized turbulent kinetic energy with vanes was observed to be relatively low in the core region. When the vanes were attached, the value of the circulation over the core region increased from 0.151 to 0.155; furthermore, Sc/Sin also increased by 3%. The results indicate that the vortex stability improved after installing the vanes. The concentration of particulate matter was measured to quantify the improvement in the performance of the vortex ventilation system. The improvement was evaluated by the increasing ventilation rate of up to 5.5% with vanes, which is attributed to the increase in vortex strength and stability. The results can be utilized as basic information to design vortex ventilation systems for large-scale factories.