TY - JOUR
T1 - Flame propagation experiment of PMMA particle cloud in a microgravity environment
AU - Kobayashi, Hideaki
AU - Ono, Naomichi
AU - Okuyama, Yozo
AU - Nioka, Takashi
N1 - Funding Information:
The authors acknowledge the financial support of NEDO (New Energy and Industrial Technology DeveI-opment Organization) and JSUP (Japan Space Utilization Promotion Center). The m~thors also would like to express sincere thanks to Mr. S. Hasegawa for his technical assistance.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1994
Y1 - 1994
N2 - The flame propagation experiments on clouds of purely spherical PMMA particles in a microgravity environment were conducted by using the Japan Microgravity Center (JAMIC) drop shaft, where a microgravity condition of 10-4 g for 10 s is available. The exact measurement of the burning velocity of the particle cloud was impossible due to the particle sedimentation in normal gravity up to now. The particle cloud was created using a fluidized-bed-type device and suspended in the flame propagation tube. The cloud was ignited at the open end of the tube, and the flame speed was measured by charge coupled device (CCD) video camera images. The flame speed in normal gravity was also measured, and the two groups of results were compared. The results showed that the flame speed in normal gravity was considerably larger than for ordinary gaseous flames, since turbulent combustion occurred due to the residual turbulence of the flow and the turbulence generated by the particle sedimentation. On the other hand, in the microgravity environment, when the cloud was ignited 6 s after the release of the capsule, the particles were quiescent and dispersed with sufficient uniformity, indicating the effectiveness of the long duration micorgravity environment on the decay of turbulence. The flame speed decreased drastically in comparison with normal gravity cases, but the dependence of the flame speed on the particle concentration was similar to that in normal gravity.
AB - The flame propagation experiments on clouds of purely spherical PMMA particles in a microgravity environment were conducted by using the Japan Microgravity Center (JAMIC) drop shaft, where a microgravity condition of 10-4 g for 10 s is available. The exact measurement of the burning velocity of the particle cloud was impossible due to the particle sedimentation in normal gravity up to now. The particle cloud was created using a fluidized-bed-type device and suspended in the flame propagation tube. The cloud was ignited at the open end of the tube, and the flame speed was measured by charge coupled device (CCD) video camera images. The flame speed in normal gravity was also measured, and the two groups of results were compared. The results showed that the flame speed in normal gravity was considerably larger than for ordinary gaseous flames, since turbulent combustion occurred due to the residual turbulence of the flow and the turbulence generated by the particle sedimentation. On the other hand, in the microgravity environment, when the cloud was ignited 6 s after the release of the capsule, the particles were quiescent and dispersed with sufficient uniformity, indicating the effectiveness of the long duration micorgravity environment on the decay of turbulence. The flame speed decreased drastically in comparison with normal gravity cases, but the dependence of the flame speed on the particle concentration was similar to that in normal gravity.
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U2 - 10.1016/S0082-0784(06)80817-9
DO - 10.1016/S0082-0784(06)80817-9
M3 - Article
AN - SCOPUS:0010515495
VL - 25
SP - 1693
EP - 1699
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
SN - 1540-7489
IS - 1
ER -