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Hajieghrary, Omid

University of British Columbia

This work presents initial results of a new method to apply friction modifier materials for railroad applications along with a novel particle concentration measurement method for two-phase flows. Until now, railroad friction management systems used liquid friction modifiers or solid sticks to apply the material to the top of the rail or to a moving train’s wheel to reduce the friction. We investigate in lab experiments a new method of applying solid lubricant powders such as molybdenum disulfide (MoS2) and graphite directly on top of the rail using electrostatic powder coating. To design and assess the performance of an applicator for spray or powder coating, it is useful to know the particle concentration in the particle jet. The concentration distribution data will aid in modifying the design of the applicator to achieve the desired deposition pattern. Current methods of concentration measurements such as laser Doppler anemometry (LDA)/phase Doppler anemometry (PDA) and planar nephelometry are excellent to provide accurate local measurements of concentration but are expensive and complicated to set up and operate. Our proposed measurement method is based on light extinction and is much easier to set up and use. This method is capable of providing particle concentration statistics for axisymmetric distributions. We show that the extinction efficiency measured with this method for a given particle agrees with known values (of somewhat less than two) for a non-ideal imaging setup. Furthermore, we demonstrate that the concentration distribution of a jet at the exit of a pipe nozzle as well as downstream is similar to that observed by previous researchers. We also present data on the deposition efficiency of electrostatic powder coating for railroad friction management systems under different test conditions. The results show that applying pure MoS2 or graphite achieves low deposition efficiencies and these materials should be surface treated with a non-conductive coating before being applied. We also discuss how the newly developed particle concentration measurement method can be used to design and monitor the performance of the new railroad friction modifier applicator.

Text

2022-10-31

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/80092

Mechanical Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/