摘要
由落塔仓产生的微重力提供了一种独特的环境 ,可克服粉尘云在地面实验时因受重力影响而产生的沉降现象 ,使封闭容器内的整个燃烧过程能维持粉尘云的稳定悬浮 ,保证粉尘燃烧机理的实验研究中粉尘的实际浓度与初始名义浓度相符 ,令粉尘浓度名符其实地成为一个独立参变量。在 12 m落塔提供的 10 - 2 g,1.2 s微重力环境下对球形铝粉 (d50 =7μm)与球形玉米粉 (d50 =2 0μm)两种粉尘的等容燃烧特性进行了系统的实验研究。实验结果经与地面实验结果进行比较与分析后定量给出了粉尘浓度保持不变时 ,粉尘爆炸特性随扬尘湍流强度衰减而变化的规律以及在地面上重力沉降令粉尘浓度变小后对粉尘爆炸特性的影响。最后还讨论了实验容器过小而引起的部分实验数据失真的原因。
For the studies of constant volume dust combustion,the microgravity environment can provide a steady suspension of dust cloud in the vessel during the combustion process.In this case,the real dust concentration during the combustion process will be kept constant and equal to the initial nominal dust concentration.The dust concentration can be treated as an independent variable of turbulent intensity.A 12 m height drop tower of Lodz University of Poland was employed for providing the microgravity environment in the present study,in which there have been 10 -2 g and 1.2 s of test time.In present study systematic experiments of constant volume dust combustion under both the microgravity and gravity environments were carried out.Aluminum ( d 50 =7.2 μm) and cornstarch ( d 50 =20 μm) dusts have been tested.The comparison and analysis of the experimental results between microgravity and gravity environments demonstrate quantitatively the effect of dispersion induced turbulent intensity on dust explosion characteristic,while the dust concentration keeps constant.The effect of dust concentration reduction by gravity sedimentation on dust explosion characteristic is also examined.Finally,the distortion of experimental data resulting from too small a volume of the test vessel is discussed.
出处
《燃烧科学与技术》
EI
CAS
CSCD
1999年第3期223-230,共8页
Journal of Combustion Science and Technology
基金
国家自然科学基金
关键词
微重力
粉尘爆炸
等容燃烧
湍流
燃烧机理
Microgravity,Dust explosion,Constant volume combustion,Turbulence
