Analytical predictions of shapes of laminar diffusion flames in microgravity and earth gravity
Analytical predictions of shapes of laminar diffusion flames in microgravity and earth gravity
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DOI：
10.1080/13647830801966146
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发表时间：
2008-07
影响因子：
1.3
通讯作者：
S. S. Krishnan-S.;J. M. Abshire;P. Sunderland;Z. Yuan;J. Gore
中科院分区：
文献类型：
--
作者：
S. S. Krishnan-S.;J. M. Abshire;P. Sunderland;Z. Yuan;J. Gore
火焰形状是火焰的一个重要的观测特征，可以用来衡量火焰的性质，如热释放速率和辐射。火焰形状受燃料类型、氧化剂中的氧含量、反向燃烧和重力的影响。本研究的目的是了解高氧浓度，反向燃烧，和重力对火焰形状的预测效果。火焰形状获得从最近的分析模型，并与实验数据进行比较，为一些反向和正常的乙烷火焰配置与不同的氧浓度在氧化剂和地球重力和微重力条件下。将罗珀火焰形状模型推广应用于圆形燃烧器上层流气体射流正扩散火焰和反扩散火焰的完整火焰形状预测。将Spalding模型推广到反扩散火焰。结果表明，扩展的罗珀模型对微重力和地球重力条件下的火焰都有较好的预测效果，但对地球重力条件下的氧正扩散火焰的预测效果较差。研究结果还显示，在微重力条件下，火焰温度趋于降低，这与过去的实验观察结果一致。讨论了用扩展的罗珀模型预测火焰形状的一些关键特性和描述火焰形状所需的参数。
Flame shape is an important observed characteristic of flames that can be used to scale flame properties such as heat release rates and radiation. Flame shape is affected by fuel type, oxygen levels in the oxidiser, inverse burning and gravity. The objective of this study is to understand the effect of high oxygen concentrations, inverse burning, and gravity on the predictions of flame shapes. Flame shapes are obtained from recent analytical models and compared with experimental data for a number of inverse and normal ethane flame configurations with varying oxygen concentrations in the oxidiser and under earth gravity and microgravity conditions. The Roper flame shape model was extended to predict the complete flame shapes of laminar gas jet normal and inverse diffusion flames on round burners. The Spalding model was extended to inverse diffusion flames. The results show that the extended Roper model results in reasonable predictions for all microgravity and earth gravity flames except for enhanced oxygen normal diffusion flames under earth gravity conditions. The results also show trends towards cooler flames in microgravity that are in line with past experimental observations. Some key characteristics of the predicted flame shapes and parameters needed to describe the flame shape using the extended Roper model are discussed.