TY - JOUR
T1 - Numerical analysis of particle dispersion and combustion characteristics on a piloted coaxial pulverized coal jet flame
AU - Ahn, Seongyool
AU - Tanno, Kenji
AU - Watanabe, Hiroaki
N1 - Funding Information:
This work is partially supported by JSPS KAKENHI Grant Number 25420173 and 16K06125, and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2013R1A6A3A03027849).
Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2017
Y1 - 2017
N2 - A numerical simulation was performed and validated on a piloted coaxial pulverized coal jet flame by means of large eddy simulation (LES) in which the dynamic Smagorinsky SGS model and the Lagrangian particle tracking model were employed. In the devolatilization process, a postulate substance, CaHbOc, was considered as the devolatilized gas. For gaseous phase reactions, a simple two-step global kinetic mechanism was implemented. For a solid phase reaction, a two-step char oxidation reaction was installed. Results were compared to an experimental result in terms of particle distribution, gaseous temperature, gas composition, and particle velocity. The particle distribution result shows that particle dispersion for the combustion case is narrower than that for the non-combustion case. This phenomena is discussed by observing an axial interphase momentum transfer. The axial momentum of fluids can be maintained as high or similar to the particles by combustion, so momentum transfer is limited in the combustion case. It is also confirmed in the particle and gas velocity results. Time-averaged temperature and mole fractions of gases capture the featured characteristics of the experiment well. From these results, an effect of devolatilized gas combustion on particle dispersion and stream flow are discussed. And it is revealed from instantaneous results that particles tends to form groups following the edge of the devolatilized gas combustion.
AB - A numerical simulation was performed and validated on a piloted coaxial pulverized coal jet flame by means of large eddy simulation (LES) in which the dynamic Smagorinsky SGS model and the Lagrangian particle tracking model were employed. In the devolatilization process, a postulate substance, CaHbOc, was considered as the devolatilized gas. For gaseous phase reactions, a simple two-step global kinetic mechanism was implemented. For a solid phase reaction, a two-step char oxidation reaction was installed. Results were compared to an experimental result in terms of particle distribution, gaseous temperature, gas composition, and particle velocity. The particle distribution result shows that particle dispersion for the combustion case is narrower than that for the non-combustion case. This phenomena is discussed by observing an axial interphase momentum transfer. The axial momentum of fluids can be maintained as high or similar to the particles by combustion, so momentum transfer is limited in the combustion case. It is also confirmed in the particle and gas velocity results. Time-averaged temperature and mole fractions of gases capture the featured characteristics of the experiment well. From these results, an effect of devolatilized gas combustion on particle dispersion and stream flow are discussed. And it is revealed from instantaneous results that particles tends to form groups following the edge of the devolatilized gas combustion.
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U2 - 10.1016/j.applthermaleng.2017.06.103
DO - 10.1016/j.applthermaleng.2017.06.103
M3 - Article
AN - SCOPUS:85021307904
SN - 1359-4311
VL - 124
SP - 1194
EP - 1202
JO - Applied Thermal Engineering
JF - Applied Thermal Engineering
ER -