毫米级单颗煤粒富氧条件下着火特性实验研究

A monochromatic imaging technique was developed and applied to retrieve the surface temperature of the coal particle using a short wavelength infrared (SWIR) camera. An experimental study on the effects of oxygen concentration, radius meter and N₂/CO₂ diluent gas ignition on the ignition and combustion characteristics of mms diameter single coal particle was conducted for three coal ranks. It was found that the flame luminosity increased considerably while ignition delay time and ignition temperature decreased with increasing oxygen concentration. Unlike DT bituminous coal particles, the volatile flame ejection phenomenon do not occur for HLE lignite coal particles. JX anthracite coal particles ignite heterogeneously only. For the same test condition, the particle surface temperature at the ignition moment slightly increase while the inner particle temperature sustainably decrease with increasing particle radius (~mm). The inconsistent trends of coal particle ignition temperature with increasing particle diameter proposed by other literature are interpreted by the experimental results, which are caused by the large temperature gradient existed in large particles. Compared with O₂/N₂ atmosphere, the ignition delay time increase and the increasing oxygen concentrations play a more important role in improving ignition behavior at O₂/CO₂ atmosphere condition.