A simulation study of airborne wear particles from laboratory wheel-rail contacts--颗粒学报PARTICUOLOGY

Liu, H., Jonsson, L. T. I., & Jönsson, P. G. (2016). A simulation study of airborne wear particles from laboratory wheel-rail contacts. Particuology, 28, 31-42. https://doi.org/10.1016/j.partic.2015.09.008

A simulation study of airborne wear particles from laboratory wheel-rail contacts

Hailong Liu ^a *, Lage T.I. Jonsson ^{a b}, Pär G. Jönsson ^a

a KTH-Royal Institute of Technology, Division of Applied Process Metallurgy, Department of Materials Science and Engineering, SE-100 44 Stockholm, Sweden
b FOI, Swedish Defence Research Agency, Division of CBRN Defence and Security, SE-901 82 Umeå, Sweden

10.1016/j.partic.2015.09.008

Volume 28, October 2016, Pages 31-42

Received 6 November 2014, Revised 24 August 2015, Accepted 15 September 2015, Available online 30 December 2015, Version of Record 4 August 2016.

E-mail: hailongl@kth.se

Highlights

• A model study of airborne wear particle transport (<100 nm) in an enclosed space was presented.

• The flow pattern inside the chamber was significantly influenced by the disc rotation.

• A very slow growth of particle concentration away from the outlet side was observed.

• The estimated particle loss rate at the outlet was about 70% after 240 s.

• Numerical simulation results were validated against laboratory measurements.

Abstract

Laboratory measurements of airborne particles from sliding contacts are often performed using a tribometer located in a ventilation chamber. Although knowledge of particle transport behavior inside the chamber is required because it can influence the analysis of measurements, this knowledge is lacking. A numerical model was built based on the same geometry as a pin-on-disc measurement system to explain particle transport behavior inside the chamber and to determine the deviation between real amounts of generated and measured particles at the outlet. The effect of controlled flow conditions on the airflow pattern and particle transport inside the chamber was studied for different experimental conditions. Calculations show that a complex airflow pattern is formed by the spinning disc, and that it differs for each rotational speed. Simulation results reveal that particle transport in the chamber is governed mainly by the airflow pattern. The deposition velocity in the chamber was estimated and the possibility that part of the generated particles would remain in the chamber was studied. This led to an approximate estimation of particle loss rate. A comparison between experimental and simulated results with respect to the particle mass flow rate close to the outlet yields a reference factor of 0.7, which provides an indication of the difference between measured and real values.

Graphical abstract

Keywords

Airborne particles; Particle transport; Concentration; Particle loss rate; Deposition velocity

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