中引式气力输送系统的实验研究

鉴于国、内外目前尚未对中引式气力输送系统特性进行研究，而它又有独立、串联和远近距离均适应的优点等，所以探讨了中引式气力输送系统的流动模式、管道阻力特性和输送压力频谱特性等。实验结果表明中引式气力输送随着操作气速分别为2、4和8m／s的变化，管内灰栓的流动模式也相应发生变化分别为：柱塞流、栓流和悬浮流；栓流压力频谱振幅最大，易成为独栓，属不稳定流动，输送量与柱塞流相当，柱塞流压力频谱较小，灰栓气栓相间的多栓流属基本稳定流动，悬浮流压力频谱最低，属稳定流动，输送量最低，输送速度最快，管道易磨损；柱塞流、栓流及悬浮流模式，对于给定物料操作气速与输送平均压力之间随着操作气速增加，输送压力逐渐下降。

The Experimental Research on the Middle-pipe Pneumatic Conveying System

There hasnt been any study, neither at home nor abroad, on the characteristics of the pneumatic conveying system of the vessel with middle-pipe yet, which is featured by the edges such as, among others, the adaptability regardless of being independent, in series, or far and near in distance. This paper elaborates on the flow pattern, piping resistance characteristics and transportation pressure spectral characteristics of pneumatic conveying system of the vessel with middle-pipe. Experimental results show that when the superficial air velocity changes respectively by 2, 4 and 8m/s under the pneumatic conveying system of the vessel with middle-pipe, the flow patterns of ash slug is correspondingly changed in forms of plug flow, slug flow and suspension flow ; The slug flow pressure spectrum, the largest and prone to becoming the single slug, is an unsteady flow whose transportation capacity is equivalent to that of the plunger piston flow. The plug flow pressure spectrum is a bit lower, the multi-slug flow between the ash slug and gas slug is the basic steady flow. The suspension flow pressure spectrum is the lowest and is a steady flow, which has the lowest transportation capacity and fastest transportation speed and is prone to wearing the pipeline. Under the plunger piston flow, the slug flow and suspension flow patternls, in terms of the relationship between the operating gas velocity and conveying average pressure for a given material, the conveying pressure gradually decreases as the operating gas velocity increases.