Spatial distribution of oil mist particles in multi-process machining plant with mixed ventilation

Indoor environmental pollution caused by oil mist particles in multi-process machining plants is a common and serious issue. Clarifying the spatial distribution of oil mist is essential for improving pollutant removal efficiency of ventilation and guiding personal protection. This study undertook three-dimensional field measurements and visualization to explore its distribution. Measurement results have shown that oil mist particles are non-uniformly distributed, with the concentrations varying by 1–2× between different locations. The horizontal non-uniformity (±30%) was significantly higher than the vertical non-uniformity (±15%). Visualization results have indicated that the type of process could significantly affect the spatial distribution of oil mist particles. In the horizontal dimension, oil mist concentrations in wet processing areas were 0.5× to 1× higher than in dry processing areas. In the vertical dimension, the higher the operating temperature, the more significant the vertical transport of oil mist, and the smaller the horizontal diffusion range during the upward movement. Due to the non-uniform spatial distribution of pollutants, zoned ventilation is more suitable than uniform exhaust ventilation for multi-process machining plants, further improving pollutant removal efficiency by 5%–14%. This study has provided data support for pollutant distribution in multi-process machining plants and guidance for improving industrial building environments.