3D imaging of individual burning char and volatile plume in a pulverized coal flame with digital inline holography

摘要

The burning behaviors of an individual coal particle in the combustion of a cloud of coal particles is of great importance because it represents the realistic situation of pulverized coal particle utilization. Digital inline holography is proposed as a tool for 3D quantitative imaging of the burning coal particle and its associated volatile flame, and demonstrated by its application to a laboratory scale pulverized coal flame. The holographic fringes of burning coal particles with volatile plumes are characterized by concentric rings as well as parallel lines. Besides the conventional 3D positions and morphologies of irregular coal particles, the volatile flames are clearly reconstructed. The instantaneous behaviors of the early stage combustion of individual coal particle in a pulverized coal flame have been observed. Typical modes of the volatile flame with respect to the coal particle, including envelope volatile flame, attached wake flame, detached wake flame, side volatile flame, are observed in the experiments. The burning behaviors of one coal particle influenced by another particle in the combustion of a cloud of particles has also been evidenced. This work demonstrates that digital inline holography has the powerful capacity of simultaneously measuring reacting multiphase objects in hostile environments. (C) 2017 Elsevier Ltd. All rights reserved.