铝粉－空气混合物燃烧转爆轰（DDT）过程的实验研究

AN EXPERIMENTAL INVESTIOATION OF DEFLAGRATION TO DETONATION TRANSITION(DDT)IN ALUMINUM OUST-AIR MIXTURE

在水平粉尘爆轰管上分别对２μｍ、５μｍ和１３μｍ三种粒径的铝粉－空气混合物进行了弱点火条件下燃烧转爆轰的实验研究。实验分别考察了粉尘浓度、颗粒尺度及扬尘方法等因素对爆轰特性（如爆轰速度、最大压力等）的影响。结果表明，２μｍ球形铝粉最大爆轰压力达７．８ＭＰａ、稳态爆速达１．９５ｋｍ／ｓ；５μｍ铝粉亦有爆轰特征，但状态较弱；１３μｍ的铝粉达不到爆轰。混合物的浓度对爆轰参数有影响，并存在最优浓度，在此浓度下，爆轰参数取得最大值，而且最优浓度的值随粉尘颗粒直径增加而增大。扬尘方法对爆轰特性有影响，预混粉尘与激波卷扬粉尘对比实验表明，其压力与速度的典型差别分别高达３００％与７４％。

The experimental researches of deflagration to detonation transition:(DDT)of three mean diameter(2μm,5μm and 13μm)of aluminum dust dispersed in air have been made under the condition of weak ignition in horlzontal dust detonation tube. The influences of dust concentration, dust particle size and dust dispersion methed on the characteristics of detonation,included detonation velocity,maximum pressure,etc.,have been examined respectively. The ex-perimental results indicate that the maximum detonation pressure and stable detonation velocity of 2μm aluminum dust reaches 7.8MPa and 1.95 km/s,5 μm dust has some characteristics of det-onation, but conditions are weaker,13μm dust can’t reach to detonation. The concentration of dust has effect on detonation parameters.There are optimum concentration under which detona-tion parameters reach maximum,and the position of optimum cdncentration increases with dust particle size. The comparison of the experiments of premixed dust and shock raising dust demon-strates that the dust dispersion methods have effcets on the characteristics of detonation,the typi-cal differences of pressure and velocity get as high as 300%and 74%respectively.