Generation of airborne wear particles from wheel-rail contact during rolling/sliding and pure sliding contact

초록

Electric railway transportation is considered an environmentally friendly transport system. However, it releases airborne wear particles (AWPs), which have an adverse effect on human health. AWP generation from wheel-rail contact during rolling/sliding and pure sliding contact has not been studied extensively. This study aims to investigate the generation of AWPs and their particle size distribution under both rolling/sliding and pure sliding contact by analyzing AWP generation under three different normal loads at a circumferential velocity of 90 km/h. AWP number concentrations (NCs) were measured using two particle sizing instruments, which are a fast mobility particle sizer (FMPS) that measures particles in the range 5.6-560 nm and an optical particle sizer (OPS) that measures particles in the range 0.3-10 mu m. Total and maximum AWPNCs were analyzed as a function of slip rate, and particle size distribution analysis was conducted. Results indicated that AWPNCs measured by both instruments under all load conditions increased with an increase in the slip rate until it reached the maximum AWPNC value and decreased thereafter. The total and maximum AWPNCs measured by both instruments increased with an increase in the normal load. Particle size distribution results indicated that most generated particles were fine particles under all load conditions. Size distribution peaks occurred at 0.01 and 0.16 mu m for ultrafine and fine particles, respectively. All results indicate that the normal load has a significant effect on AWP generation and that ultrafine and fine particles are generated even during rolling/sliding contact.

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