Fibre optic ignition of combustible gas mixtures by the radiative heating of small particles

Applications and Optoelectronic Methods of Detection of Ammonia

“…However, the safety of optical fibre sensors is not unqualified, as it has been established that in the case of very high powers, i.e. of the order of 100 mW, or greater in multi-mode fibre, explosive risks may present themselves (Hills et al (1993); Zhang et al (1992)). Conventional optical fibres have a very small acceptance aperture, which severely restricts the amount of light that can be coupled into a fibre.…”

Methane–air mixtures ignited by CW laser-heated targets on optical fiber tips: Comparison of targets, optical fibers, and ignition delays

“…Minimum igniting powers for methane-air mixtures reported by Welzel, Schenk, Hau, Cammenga, and Bothe (2000) and Zhang, Hills, Zheng, Wall, and Samson (1992) are listed in Table 1. Target diameters above 62.5 mm required higher powers for ignition than listed in the table.…”

“…One exception was Zhang et al (1992), who reported 8% as the most easily ignited methane-air concentration. Hertzberg (1989) suggests lean methane-air mixtures ignite most easily because of selective diffusion.…”

“…This suggests that fibers with smaller cladding diameters may produce ignitions with lower powers. In the current study, ignition tests were conducted with commercially available Welzel et al (2000) 62.5 Iron-manganese oxide layer 5 304 Zhang et al (1992) 50 40 mm Appin coal particle 8 300 1 The findings and conclusions in this report are those of the author and do not necessarily represent the views of the National Institute for Occupational Safety and Health. 80 mm cladding single mode fiber in an attempt to observe any influence of cladding diameter on igniting power.…”

“…The (FeMn) 2 O 3 produced lower igniting powers for selected atmospheres when it was mixed with a ceramic adhesive and applied to large core diameter multimode optical fiber tips as a paste (Carleton, Bothe, Proust, & Hawksworth, 2000b). One exception was Zhang et al (1992), who reported that Appin coal particles ignited methane at the lowest powers.…”