Fire hazard of titanium powder layers mixed with inert nano TiO2 powder.
Fire hazard of titanium powder layers mixed with inert nano TiO2 powder.
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DOI：
10.1016/j.jhazmat.2017.12.010
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发表时间：
2018-03
影响因子：
13.6
通讯作者：
C. Yuan;Jingzhi Cai;P. Amyotte;Chang Li;Yajie Bu;Kangfu Liu;Gang Li
中科院分区：
文献类型：
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作者：
C. Yuan;Jingzhi Cai;P. Amyotte;Chang Li;Yajie Bu;Kangfu Liu;Gang Li
金属粉尘层对普通点火源的点火高度敏感，即使与高百分比的惰性固体混合也是如此。反过来，粉尘层火灾是粉尘爆炸或其他破坏性火灾的潜在点火源。研究了自然对流和强制气流条件下钛粉与惰性纳米TiO 2混合层的火焰传播速度（FSV），并将其作为评价火灾危险性的潜在参数。纳米TiO 2粉的质量分数的增加降低了钛粉混合物的FSV预期。对于微米级和纳米级Ti粉，纳米TiO 2的掺量分别为80%和90%时，可以完全抑制层火。纳米Ti粉层上的火焰传播机理不同于微米Ti粉层上的火焰传播机理。无气流条件下的FSV高于辅助气流条件下的FSV，因为传导是主要的传热机制。然而，在没有气流的FSV低于在相反的气流纳米钛粉，因为对流/辐射是占主导地位的传热机制。在辅助气流条件下，纳米钛粉混合物的飞火现象导致更大的FSV和更高的火灾危险性。
Metallic dust layers are highly sensitive to ignition from common ignition sources, even when mixed with high percentages of inert solids. In turn, dust layer fires are a potential ignition source for dust explosions or other damaging fires. Flame spread velocity (FSV), as a potential parameter for evaluating fire hazard, was investigated for titanium powder layers mixed with inert nano TiO2powder in both natural convection and in forced airflow conditions. Increased mass percentage of nano TiO2powder decreased FSV of Ti powder mixtures as expected. The mixing ratio of nano TiO2to fully suppress layer fires was 80% and 90% for micro and nano Ti powder, respectively. Mechanisms governing flame spread across a layer of nano Ti powder differed from those of a layer of micro Ti powder. FSV in no airflow conditions was higher than in aided airflow for micro Ti powder because conduction was the dominant heat transfer mechanism. However, FSV in no airflow was lower than in opposed airflow for nano Ti powder because convection/radiation was the dominant heat transfer mechanism. A fly fire phenomenon contributed to greater FSVs and higher fire hazard with nano Ti powder mixtures under aided airflow conditions.