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Cylindrical confined space is a special working place. The pollutants in such a working place are difficult to remove by traditional ventilation methods, leading to serious damage to occupational health of workers. Therefore, in order to safeguard the workers, an effective ventilation plan must be established. In this study, a swirl ventilation model was proposed. Based on the model experiments and numerical methods, the ventilation performance of the swirl ventilation and traditional ventilation modes was compared, which was followed by the investigation of the influence of swirl ratio on the swirl ventilation. The net contaminant removal efficiency Enc was proposed to assess the performance of different ventilation modes. The results show that the recirculation zone is generated in the confined space under traditional ventilation mode, which leads to the retention of pollutants. On the other hand, the recirculation zone is completely eliminated under the swirl ventilation mode, and the net contaminant removal efficiency is at least twice that of the traditional ventilation mode. Finally, it was found that with the increase in the swirl ratio, the flow mode changed from the reverse flow to the swirl flow mode, and then to recirculation flow. The reverse flow mode and the recirculation flow mode were found to be invalid flow modes. When the swirl ratio was 2.25, the most effective swirl ventilation mode could be formed. The results of this study can provide useful guidance for the ventilation design of cylindrical confined spaces. |
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