MgH_(2)粉尘火焰传播过程与热辐射特性

The Flame Propagation Process and Thermal Radiation Characteristics of MgH_(2)Dust

为了探究MgH_(2)粉尘爆炸火焰传播过程及其热辐射特性,采用改进后的哈特曼管装置对其进行点火实验,通过高速摄像机、热辐射仪和红外热成像仪同步记录MgH_(2)粉尘的火焰传播、热辐射通量和温度场变化过程。结果表明,点火后MgH_(2)火焰持续增长形成连续的燃烧区域,达到最大值后开始衰减并出现离散状火焰;粉尘质量浓度在150~1000g/m^(3)范围内,火焰前锋阵面的最大传播高度和最大传播速度随着质量浓度的增大呈现出先增大后减小的规律,均在750g/m^(3)时最大,分别达到1138mm和45m/s;热辐射通量随着粉类质量浓度的增加逐渐增大,在火球正上方的3号热辐射通量最大值达到31.7kW/m2,远高于火球两侧的1号和2号热辐射通量;火焰中心区域温度最高,向四周逐渐降低,高温区集中在火焰上部。

The improved Hartmann tube device was used for ignition experiments to investigate the flame propagation process and thermal radiation characteristics of MgH_(2)dust explosion.A high-speed camera,thermal radiometers,and the infrared thermal imager synchronous control system were used to record the flame propagation,heat radiation flux change,and temperature change process of MgH_(2)dust,respectively.The results show that after ignition,the MgH_(2)flame continues to expand to form a continuous combustion area and when it reaches the maximum,it begins to decay,and a discrete flame appears.When the mass concentration is 150—1000g/m~3,the maximum propagation height and the maximum propagation velocity of the flame front reach 1138mm and 45m/s,respectively,at 750g/m~3.In addition,the maximum heat radiation flux of No.3 above the fireball reaches 31.7kW/m~2,which is much higher than those of No.1 and No.2 on both sides.The temperature is highest in the flame center and gradually decreases around it.The high-temperature zone is concentrated in the upper part of the flame.