Error analysis of human inhalation exposure simulation in industrial workshop

Abstract

The evaluation of inhalation exposure of workers in industrial production environments is significant. Current studies on inhalation exposure in industrial workshops are quite limited and lack experimental data validation. This study established a scaled experimental cabin and performed inhalation exposure experiments. Subsequently, the validated numerical model was used to study the influences of different factors on human inhalation exposure prediction. The factors emphasize the meshing strategy, the manikin geometry and the thermal plume of the manikin. The results show that the polyhedron grid offers a greater advantage and that the required grids and computing time represent only 20% and 33% of the tetrahedral grid. CFD results are more consistent with human inhalation exposure experimental results when a 5% mean computational error is used as a criterion to verify grid independence. The inhalation exposure computational results of different manikin models differed by only about 2%. And compared with the 3D scanned model, the humanlike multi-box and single cuboid models are easier to build and consume fewer resources. Therefore, using humanlike multi-box and single cuboid models to compute human inhalation exposure in the industrial workshop is more recommended. The Ri number evaluates the intensity of the human thermal plume. The computational errors between the isothermal and thermal manikin models are 1.76%, 5.14%, 9.18%, and 14.95% for inhalation exposures with 20, 15, 10 and 5 ACH (air changes per hour), respectively, and the corresponding Ri numbers are 0.09, 0.16, 0.34, and 1.41.The computational error between the isothermal and thermal manikin models is less than 10% when the ACH is larger than 10. This study can provide a reference for the prediction of inhalation exposure of workers in industrial workshops.