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Experiments and Numerical Calculations on Laser‐induced Ignition of Single Micron‐sized Aluminum Fuel Particle
Author(s) -
Li Shengji,
Huang Xuefeng,
Zhou Donghui
Publication year - 2017
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.201600215
Subject(s) - ignition system , materials science , particle (ecology) , laser ignition , evaporation , minimum ignition energy , mechanics , microscale chemistry , aluminium , heat transfer , thermodynamics , composite material , physics , oceanography , mathematics education , mathematics , geology
This paper presents the experiments and numerical calculations on the laser‐induced ignition of single micron‐sized aluminum particle in an atmospheric pressure air flow at low Reynolds number. Experimental results demonstrate that the radiation intensity of single micron‐sized aluminum particle, during ignition, experiences first sharp rising, stable equilibrium and second steep rising stages. A simplified analytical model was built and numerically solved. Numerical results show that the three distinctive stages represent the heating, melting and evaporation, respectively. Laser radiation mainly contributes to heat aluminum particle, leading to phase transition (melting). The heat released from heterogeneous surface reaction (HSR) dominates the temperature rise of the liquid aluminum and accelerate its evaporation. During ignition, the heat loss of natural convection significantly affects the ignition performance of aluminum particle, while the heat loss of radiation toward the surrounding air only affects the evaporation rate. Threshold ignition energy of aluminum particle based on numerical calculations is in good agreement with the experiments, which strongly depends on the particle diameter. Ignition delay time depends on the particle diameter and ignition energy. This study will be beneficial to deeply recognize the ignition mechanism of single micron‐sized aluminum particle, especially in the transition region between nanoscale and microscale.