ANALITIC INVESTIGATION OF THE REGULARITIES OF CHANGING DUST CONCENTRATION DURING THE ABRASIVE DECREASE OF STONE STRUCTURES
In the process of repair or restoration of building structures, it is often necessary to strengthen building structures from limestone-shell rock, concrete, reinforced concrete, hard materials-granite, basalt, etc. by cutting or making cuts of the required size with detachable circles of synthetic diamond and cubic boron nitride (CA and CBN)
The cutting process is accompanied by considerable dust formation, which can be both harmful and dangerous factor in the work.
The aim of the work is studying the process of dust sedimentation and the regularity of the change in dust concentration during the abrasive cutting of concrete and stone materials.
Mathematical models have been developed – dust emission from under the wheel, speed of sedimentation of dust particles depending on their material, size and shape, and also depending on temperature, pressure and humidity, the concentration of dust in the working space and the concentration change during the cutting cycle are calculated.
It is shown that the velocity of the sedimentation of particles depends significantly on the shape. The higher the sphericity, the higher the sedimentation rate. The ambient temperature has little effect on the sedimentation rate, in the temperature range (-20 → + 40 °C) at which the operation takes place.
The sedimentation rate of dust particles generated by cutting the most common building stone materials also differs slightly. Almost the same sedimentation rate has dust particles obtained by cutting basalt and concrete. A bit higher is the sedimentation rate of particles from granite.
The sedimentation rate of particles of generated dust is about 600-700 cm/h or 10-11 cm/min for particles measuring 6 μm. This means that at a production height of about 2 m (200 cm) during the operating cycle (about 3 min), the dust will remain at an altitude of about 1.5 m, i.е. practically remains in the working area. This gives grounds to assert about a high concentration of dust during the cutting cycle (about 4.8 108/m3).
Bezpalova, A., Lebedev, V. (2017). Investigation of the formation process of hazardous and harmful production factors when cutting a stone for construction works. EUREKA: Physics and Engineering, 5, 30–38. doi: 10.21303/2461-4262.2017.00416
Gao, R., Li, A. (2011). Modeling deposition of particles in vertical square ventilation duct flows. Building and Environment, 46 (1), 245–252. doi: 10.1016/j.buildenv.2010.07.020
Maggi, F. (2013). The settling velocity of mineral, biomineral, and biological particles and aggregates in water. Journal of Geophysical Research: Oceans, 118 (4), 2118–2132. doi: 10.1002/jgrc.20086
Dust and respiratory tract. All about spontaneous pneumothorax. Available at: http://www.spontan.ru/pnevmokoniozy/186-pyl-i-dyxatelnye-p.uti.html
Mushchenko, B. L. (2009). Calculation of the rate of incidence of dust particles and the evaluation of the degree of influence of various forces acting on the particle. Scientific Bulletin of the Voronezh State University of Architecture and Civil Engineering, 2, 58–63.
Azarov, V. N., Bessarab, O. I., Kabaev, O. V. (2010). Theoretical studies of sedimentation rate of fine dust in the air of working rooms of engineering and construction industry enterprises. Bulletin of VolgGASU. Series: Str-in and the architect, 17 (36), 102–105.
Osada, K., Ura, S., Kagawa, M., Mikami, M., Tanaka, T. Y., Matoba, S. et. al. (2014). Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution. Atmospheric Chemistry and Physics, 14 (2), 1107–1121. doi: 10.5194/acp-14-1107-2014
Arkhipov, V. A., Usanina, A. S. (2013). A877 Movement of aerosol particles in a stream. Tomsk: Publishing House of Tomsk State University, 92.
Clift, R., Grace, J. R., Weber, M. E. (1978). Bubbles, Drops, and Particles. Academic Press, 380.
Gu, Z., Zhao, Y., Li, Y., Yu, Y., Feng, X. (2006). Numerical Simulation of Dust Lifting within Dust Devils–Simulation of an Intense Vortex. Journal of the Atmospheric Sciences, 63 (10), 2630–2641. doi: 10.1175/jas3748.1
Copyright (c) 2018 Alla Bezpalova, Vladimir Lebedev, Yuri Morozov
This work is licensed under a Creative Commons Attribution 4.0 International License.
Our journal abides by the Creative Commons CC BY copyright rights and permissions for open access journals.
Authors, who are published in this journal, agree to the following conditions:
1. The authors reserve the right to authorship of the work and pass the first publication right of this work to the journal under the terms of a Creative Commons CC BY, which allows others to freely distribute the published research with the obligatory reference to the authors of the original work and the first publication of the work in this journal.
2. The authors have the right to conclude separate supplement agreements that relate to non-exclusive work distribution in the form in which it has been published by the journal (for example, to upload the work to the online storage of the journal or publish it as part of a monograph), provided that the reference to the first publication of the work in this journal is included.