微重力场中弱强迫流动作用下的固体表面火蔓延

A Numerical Study of Flame Spreading over Solid Combustibles with Slow Forced Flow in a Microgravity Environment

本文研究了微重力条件下固体可燃物表面的火焰传播过程。建立了火蔓延的三维非稳态数学物理模型，给出了微重力条件下燃烧过程中固体可燃物气化表面耦合效应的数学处理。运用数值模拟的方法，探讨微重力条件下燃烧过程的物理机理。研究了弱强迫流动对固体表面火蔓延过程的影响，揭示了微重力场中弱强迫流动作用下出现逆风火焰比顺风火焰旺盛的独特现象，并与正常重力场的计算结果作了对比。

In this paper, flame spreading over solid combustibles in a microgravity environment has been investigated. Computational models of three-dimensional, time-dependent flame spreading in a microgravity environment have been developed, which include the treatment of interfacial coupling between gas-and solid-phase in the combustion process. The controlling mechanism of flame spreading in microgravity environments which may become oxygen-transport-limited rather than heat-transfer-limited as that in normal gravity has been studied by numerical methods.Predictions have been made of flame spreading with slow forced flow under gravitational acceleration normal to fuel surface with microgravity level of 10-3 times that of the earth. Results of the modelling effort show that the upstream flame spreads faster than the downstream flame after a period of ignition. For the sake of comparison, numerical simulations of flame spreading in normal gravity also has been taken in this study. The simulation results are basically reasonable.