Radiation effects for downward flame spread over a thermally thin fuel in a partial-gravity environment

Kuo Kuang Wu, Chiun-Hsun Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

This study explores the effects of radiation on a downward flame spread over a thermally thin solid fuel in a partial-gravity environment. The radiation effect and gravitational field strength (g) are predicted not to influence the ignition delay time. The flame-spread rate reaches a maximum at g = 0.01. At g > 0.01, the flame stretch effect dominates the behaviors of the flame. Radiation heat transfer and oxygen transport control the flame behaviors for g < 0.01. The predicted quenching limit is g = 5 × 10 -6, close to the value obtained experimentally elsewhere. Radiation has two simultaneous effects. One is to reduce the flame strength by carrying heat to the ambient. The other one is combined with upstream conduction to enhance the total forward heat transfer rate and thus preheat virgin fuel upstream. The solid fuel temperature is low and some fuel is left over in low gravity due to radiation loss. Energy analyses indicate that the conduction heat flux from the flame (̄qc) dominates its behaviors. However, radiation gradually competes with ̄qc as the gravity is reduced.

Original languageEnglish
Pages (from-to)1909-1933
Number of pages25
JournalCombustion Science and Technology
Volume176
Issue number11
DOIs
StatePublished - 1 Nov 2004

Keywords

  • Flame spread
  • Partial gravity
  • Radiation effect

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