Effects of Turbulent Mixing and Controlling Mechanisms in an Entrained Flow Coal Gasifier
Effects of Turbulent Mixing and Controlling Mechanisms in an Entrained Flow Coal Gasifier
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DOI：
10.1021/ef9011214
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发表时间：
2010-02
期刊：
影响因子：
5.3
通讯作者：
Yuxin Wu;Philip J. Smith;Jiansheng Zhang;Jeremy N. Thornock;Guangxi Yue
中科院分区：
文献类型：
--
作者：
Yuxin Wu;Philip J. Smith;Jiansheng Zhang;Jeremy N. Thornock;Guangxi Yue
在夹带流煤气炉中，湍流波动具有较大的时间和长度范围。为了弄清湍流对煤气化过程的影响以及夹带流煤气炉中不同区域的控制机理，估计了各主要过程的特征时间和长度尺度。在比较各范围内湍流混合的长度/时间尺度与均相反应和非均相反应的特征时间的基础上，研究了湍流对夹带式煤气炉内不同区域的反应和气化过程的影响。在火焰区，宏观湍流涨落与非均相反应之间存在很强的耦合效应。微尺度Kolmogorov尺度的波动对挥发分的燃烧有强烈的影响，因为这种波动破坏了颗粒的扩散边界层。在非火焰区，非均相炭气化的效果较好。
There is a large range of time and length scales of turbulent fluctuations in an entrained flow coal gasifier. To figure out the turbulent effects on coal gasification processes and the controlling mechanisms of different regions in an entrained flow coal gasifier, the characteristic time and length scales for all major processes are estimated. On the basis of the comparison between the length/time scales of turbulent mixing in all ranges and the characteristic time of homo- and heterogeneous reactions, turbulent effects on reactions and coal gasification processes in different regions in an entrained coal gasifier are studied. In the flame region, there is a strong coupling effect between macro-scale turbulent fluctuation and heterogeneous reactions. The combustion of the volatile is strongly affected by the fluctuation of micro-scale Kolmogorov scales because the diffusion boundary layer of the particles is destroyed by this kind of fluctuation. In the nonflame region, the heterogeneous char gasificatio...