粉煤密相气力输送流型

基于电容层析成像技术对粉煤密相气力输送系统的流型进行了研究,获得了水平管和竖直上升管粉煤密相气力输送系统的典型流动形态。研究结果表明,水平管输送时的流型随时间复杂多变,典型流型有满管流、沉积层流、悬浮流等;统计分析发现,随表观气速不同,存在明显的主导流型;结合固相速度及管道压力信号分析,展示出其与流型之间存在一定的对应关系,进一步证实了密相气力输送系统的不稳定性特征。对竖直上升管的ECT测试结果表明,输送流型为环核结构。

Flow regime of pulverized coal in dense-phase pneumatic conveying system

Based on electrical capacitance tomography technique, the flow regime of dense-phase pneumatic transportation of pulverized coal was investigated.Typical flow regimes in the horizontal pipe and riser were obtained.The study indicated that the flow regime in the horizontal pipe varied significantly with time and there existed several flow regimes, such as full pipe flow, settled layer flow, suspension flow, etc.Statistical analysis results revealed that there were obvious prevailing flow regimes, which changed with superficial gas velocity.An analysis on solids velocity and pressure signals showed that the flow regime correlated reasonably well with pressure signals, which proved the inherent instability of dense phase pneumatic conveying.On the other hand, the dynamic test result of the riser showed that the flow regime was mainly core-annulus structure.