微重力环境中空气流动与辐射热损失对火焰传播的影响

本文建立了包含辐射热损失的火焰沿热薄燃料表面传播的数学模型。燃毁点的密度作为待求参数出现在模型中。数值计算结果表明，在微重力环境中，火焰传播速度随空气流动速度的变化出现峰值。对比无辐射热损失模型和有辐射热损失模型的计算结果发现，辐射热损失是形成上述微重力燃烧特征的原因。在静止的微重力环境中或弱空气流动速度下，辐射热损失使燃毁点处有大量的残碳生成，但随着空气流动速度的增大，残碳生成量迅速减小。

THE EFFECTS OF OPPOSED FLOW VELOCITY AND RADIATIVE HEAT LOSSES ON THE FLAME SPREADING OVER THERMALLY THIN FUELS

A model was developed of flame spreading over thermally thin fuels in thispaper, in which gaseous and solid surface radiative heat losses are included and the soliddensity at burnout exists as a parameter. The calculated results show that a peak value offlame spreading rate is reached when the opposed flow velocity is increased to a critical value,after which the flame spreading rate decreases monotonically as the opposed flow velocityis increased further. The radiative heat losses are determined as the cause of the aboveflame spreading characteristics by comparing the results of non-radiative model with that offull-radiative model. As another characteristics of microgravity flame spreading, the densityat burnout in the quiescent microgravity is much greater than the counterpart in the normalgravity, which is caused by the cooling effect of radiative heat loss on the gas and the fuelsurface near and at the burnout.