Studies of microgravity diffusion flames

Various topics relating to flame stability are discussed. A linear stability analysis is performed on a set of simplified equations to discern regions of both cellular and oscillatory flame instabilities of diffusion flames. This is performed for a one-dimensional model and also for a two-dimensional model representing a simple version of an “edge flame”. It is shown that the one-dimensional model agrees well with the two-dimensional model in a qualitative sense. A one-dimensional model of laminar premixed flame annihilation is examined to identify the effect of non-unity Lewis number on flame front extinction. Conclusions are drawn regarding the implications for turbulent flame stability. Additionally, a heat transfer analysis is performed for a slot burner configuration of a diffusion flame. Here, characteristic profiles for the conductive heat loss from a lifted tri-brachial flame are examined. Correlations are presented and compared with experimental data.