Flame behavior in heated porous sand bed

S. G. Kim, T. Yokomori, N. I. Kim, S. Kumar, S. Maruyama, K. Maruta

Research output: Contribution to journalConference article

16 Citations (Scopus)

Abstract

This paper reports experimental and numerical investigations on the combustion characteristics of a lean methane-air mixture in a heated porous sand bed. The porous bed consisted of sand (SiO2) particles with a mean particle diameter of 0.56 mm. The horizontally placed quartz tube was heated externally to initiate the combustion reaction in the porous bed combustor. The stabilized flame location curve as a function of averaged mixture velocity was obtained for various equivalence ratios. Contrary to the earlier finding of a C-shape flame stabilization behavior, a new S-shape behavior was observed in the present study. This can be divided into three regimes: high, moderate, and low velocity regimes. In the low velocity regime, flame with very weak luminosity was confirmed and the stabilized flame location moved down-stream with the increase of the mixture velocity. For the moderate velocity regime, a stable flat flame was observed and the flame location moved upstream with the increase of the mixture velocity. An oscillatory flame behavior was observed in the high velocity regime. In this oscillatory mode, the flame front oscillated with a characteristic time period of the order on 1 h and increased with the increase of the mixture velocity. In order to further understand these experimental results, one-dimensional computational studies with detailed chemistry and heat transfer mechanisms were carried out. The computational results were in good agreement with experimental observations. The computations showed that solid-to-solid radiation played a significant role in the flame stabilized location. From the examination of the flame structure, it was found that the flame behavior in the low velocity regime was similar to that of the flameless combustion mode.

Original languageEnglish
Pages (from-to)2117-2124
Number of pages8
JournalProceedings of the Combustion Institute
Volume31 II
Issue number2
DOIs
Publication statusPublished - 2007 Jan 1
Externally publishedYes
Event31st International Symposium on Combustion - Heidelberg, Germany
Duration: 2006 Aug 52006 Aug 11

Keywords

  • Flameless combustion
  • Oscillatory flame
  • Porous bed combustion
  • Solid-to-solid radiation

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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    Kim, S. G., Yokomori, T., Kim, N. I., Kumar, S., Maruyama, S., & Maruta, K. (2007). Flame behavior in heated porous sand bed. Proceedings of the Combustion Institute, 31 II(2), 2117-2124. https://doi.org/10.1016/j.proci.2006.08.070