摘要
选择真空干燥后的食品级玉米淀粉,利用激光粒度分析仪和扫描电镜分析颗粒的形状和几何尺寸。利用高速摄像机技术,在1.2 m长的垂直独头管道内对玉米淀粉粉尘云的爆炸火焰传播行为进行实验研究,考察有、无障碍物的条件下粉尘云浓度对火焰传播的影响。结果表明:火焰整体上呈先增加再降低的发展趋势。粉尘云浓度和障碍物均对玉米淀粉粉尘云火焰传播形态及火焰速度具有显著影响。随粉尘云浓度增加,粉尘燃烧不充分,导致出现最大火焰速度和火焰亮度均逐渐降低,火焰轮廓不清晰,火焰分段等现象。障碍物的湍流效应会加速粉尘燃烧,增加粉尘火焰传播速度,提高火焰亮度和轮廓清晰度,但粉尘云浓度增加会降低障碍物对火焰传播的加速效应,促使最大火焰速度呈先增加再降低的趋势。
Taking food grade corn starch after vacuum drying as example,particle shape and size were analyzed by laser particle size analyzer and SEM.High speed camera technology was used to study explosive flame propagation behavior of corn starch dust cloud in a 1.2 m long vertical half-open tube,and the influence of dust cloud concentration on flame propagation with or without obstacle was investigated.The results showed that the flame speed overall increases at first and then decreases.Both dust cloud concentration and obstacle have significant influence on the flame propagation pattern and flame speed of corn starch dust cloud.With the increase of dust cloud concentration,the dust combustion is not sufficient,resulting in the gradual decrease of the maximum flame speed and flame brightness and unclear flame contour and flame segment phenomenon.The turbulence effect of obstacles will accelerate the combustion of dust,increase the speed of dust flame prop-agation,improve the flame brightness and contour clarity.However,an increase in the concentration of dust clouds will reduce the accelerated effect of obstacles on flame propagation,and promote the maximum flame speed to increase at first and then decrease.
作者
杨凯
陈彦斌
庞磊
张志文
任佳奇
李思刚
刘文帅
YANG Kai;CHEN Yan-bin;PANG Lei;ZHANG Zhi-wen;REN Jia-qi;LI Si-gang;LIU Wen-shuai(School of Safety Engineering,Beijing Institute of Petrochemical Technology,Beijing 102617,China;Beijing Academy of Safety Engineering and Technology,Beijing 102617,China)
出处
《消防科学与技术》
CAS
北大核心
2020年第5期596-600,共5页
Fire Science and Technology
基金
北京市科技新星计划项目(Z181100006218092)
北京市优秀人才培养资助青年拔尖个人项目(2016000026833ZK05)
北京市大学生研究训练[URT]计划项目(2019X00008)。
关键词
玉米淀粉
粉尘云浓度
火焰速度
障碍物
火焰传播形态
corn starch
dust cloud concentration
flame velocity
obstacle
flame propagation pattern
