TY - JOUR
T1 - Pulsating flame propagation of PMMA particle cloud in microgravity
AU - Hanai, Hironao
AU - Maruta, Kaoru
AU - Kobayashi, Hideaki
AU - Niioka, Takashi
N1 - Funding Information:
The authors gratefully acknowledge Mr. Susumu Hase-gawa and Mr. Mitsuru Ueki for their assistance with our microgravity experiments. This work was performed under the management of the Japan Space Utilization Promotion Center as a part of the R&D project of Advanced Combustion Science Utilizing Microgravity supported by the NEDO (New Energy and Industrial Technology Development Organization).
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 1998
Y1 - 1998
N2 - Although a large number of studies have been made on heterogeneous combustion of solid particle clouds, the combustion mechanisms of these systems are not well understood due to the complexity of the combustion processes and difficulties in conducting experiments. The purpose of this paper is to show a particular phenomenon found in flame propagation of PMMA particle clouds. The experiments were performed in microgravity to prevent sedimentation of the particles and the effect of buoyancy on the flame using a closed-vessel method and spherical polymethylmethacrylate (PMMA) particles as fuel. Observation of the flame using a CCD video camera and the time history of pressure and ionization current showed that the flame propagation with alternating fast and slow modes occurred and that the flame was characterized by oscillation. This phenomenon is called "pulsating flame" in this paper. The pulsating flame appears only near the lean flammability limit. As fuel concentration increases from the lean flammability limit, the frequency of the pulsating flame increases first and then decreases; beyond a certain equivalence ratio, the pulsating flame does not occur. The frequency also decreases with increasing mean diameter of the particles. Explanation of the mechanism of this pulsating flame phenomenon was attempted based on the concept of heat absorption of the particles in burned gas and radiative heat transfer to the particles in a fresh mixture.
AB - Although a large number of studies have been made on heterogeneous combustion of solid particle clouds, the combustion mechanisms of these systems are not well understood due to the complexity of the combustion processes and difficulties in conducting experiments. The purpose of this paper is to show a particular phenomenon found in flame propagation of PMMA particle clouds. The experiments were performed in microgravity to prevent sedimentation of the particles and the effect of buoyancy on the flame using a closed-vessel method and spherical polymethylmethacrylate (PMMA) particles as fuel. Observation of the flame using a CCD video camera and the time history of pressure and ionization current showed that the flame propagation with alternating fast and slow modes occurred and that the flame was characterized by oscillation. This phenomenon is called "pulsating flame" in this paper. The pulsating flame appears only near the lean flammability limit. As fuel concentration increases from the lean flammability limit, the frequency of the pulsating flame increases first and then decreases; beyond a certain equivalence ratio, the pulsating flame does not occur. The frequency also decreases with increasing mean diameter of the particles. Explanation of the mechanism of this pulsating flame phenomenon was attempted based on the concept of heat absorption of the particles in burned gas and radiative heat transfer to the particles in a fresh mixture.
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U2 - 10.1016/S0082-0784(98)80123-9
DO - 10.1016/S0082-0784(98)80123-9
M3 - Conference article
AN - SCOPUS:0032277337
VL - 27
SP - 2675
EP - 2681
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
SN - 1540-7489
IS - 2
T2 - 27th International Symposium on Combustion
Y2 - 2 August 1998 through 7 August 1998
ER -