Computational and Experimental Analysis of Ultrafine Particle Dispersion During Granite Polishing

Abstract

The granite manufacturing industry is an environment in which workers are exposed to high levels of ultrafine particles (UFPs) and crystalline silica dust. Overexposure to crystalline silica can cause health problems, in particular silicosis. This fatal lung disease persists worldwide despite knowledge of methods to control it. One way to partially overcome the problem of subjectivity and try to achieve objective experimental results is to run field crystalline silica dust surveys with trained human assessors (panelists). Such field inspections allow the determination of ambient air concentrations and are now seen as being a more convenient method for UFP impact assessment in the field. One drawback of field inspections is that they can get rather expensive, especially if the survey is conducted for an extended period of time involving a high number of panelists. This paper reviews the techniques that can be adopted to measure UFPs in the field and discusses how such techniques can be used as an alternative to, or in combination with, gas tracer dispersion methods for UFP impact assessment purposes, and how the results of field UFP measurements and model outputs can be related and compared to each other. Two simulation methods were used to study crystalline silica dust exposure during the granite polishing process (experimental and numerical). This study presents a method to measure UFP dispersion during granite manufacturing processes. A computational model was constructed to simulate the physical problem. The numerical study was carried out, on a simplified configuration (bench), modeling particle distribution near a rotating tool. CFD simulation results were compared to the experimental data using NaCl particles, a tracer gas (CO₂), and UFP dispersion from granite polishing. The results showed good agreement between the two methods.