School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China.
Int J Environ Res Public Health. 2022 Dec 7;19(24):16415. doi: 10.3390/ijerph192416415.
Owing to the airflow field within airtight machines, oil mist particles escape with the airflow from the machine shell gaps and are emitted externally to the post-environmental area, causing air pollution and threatening workers' health. The existing local exhaust system is ineffective in capturing oil mist particles. This study proposes a gas-oil separation device that can "in-situ control" the oil mist particles in situ and weaken their outgoing emission and that uses numerical simulations to compare and analyse the emission characteristics of oil mist particles, before and after the addition of the separation device at different exhaust air volumes and particle emission speeds, and to design the structural parameters of the device to improve the separation efficiency of oil mist particles. The structural parameters of the proposed device are designed to improve the separation efficiency of oil mist particles. Studies have shown that for every 200 m/h increase in exhaust air volume, the capture efficiency increases by around 3%, and the particle concentration at the gap in the machine loading door decreases from 9.4 × 10 kg/m to 7.7 × 10 kg/m. The overall escape rate of oil mist particles is in the range of 10-13% after the addition of a pressure relief device. Numerical simulations are performed to analyse the effects of inlet airflow velocity, folding plate spacing, and folding plate angle on the separation efficiency of oil mist particles. Results show that an increase in the inlet velocity of the airflow increases the particle separation efficiency. The most suitable structural parameters for the separation device and the machine are as follows: 60° angle of the folding plate and 30 mm distance between plates, where the separation efficiency is above 80%, and the average separation efficiency is about 86%. The results of this study can be used as a reference for the study of the emission of oil mist particles from enclosed mechanical cutting machines.
由于密封机器内的气流场，油雾颗粒会随气流从机器外壳缝隙逸出，并排放到环境区域外，造成空气污染，威胁工人健康。现有的局部排气系统无法有效地捕获油雾颗粒。本研究提出了一种气-油分离装置，可以“就地控制”油雾颗粒，并减弱其排放，利用数值模拟比较和分析在不同排气量和颗粒排放速度下添加分离装置前后油雾颗粒的排放特性，并设计装置的结构参数，以提高油雾颗粒的分离效率。设计装置的结构参数是为了提高油雾颗粒的分离效率。研究表明，排气量每增加 200m/h，捕获效率提高约 3%，机器装料门缝隙处的颗粒浓度从 9.4×10kg/m 降低到 7.7×10kg/m。添加减压装置后，油雾颗粒的总逃逸率在 10-13%范围内。进行数值模拟以分析入口气流速度、折流板间距和折流板角度对油雾颗粒分离效率的影响。结果表明，气流入口速度的增加会提高颗粒分离效率。分离装置和机器最适合的结构参数为：折流板角度 60°，板间距 30mm，分离效率超过 80%，平均分离效率约为 86%。本研究的结果可作为密闭机械切割机床油雾颗粒排放研究的参考。
