18m循环流化床提升管内压力信号的功率谱密度分析

Power Spectral Density Analysis of Pressure Signal in an 18m Circulation Fluidized Bed Riser

以高度18m、直径80mm的提升管反应器为研究对象,基于提升管不同轴向位置的压力数据,应用功率谱密度方法分析了其内部的气-固流动特征。结果表明,提升管内的压力信号波动主要受气-固间相互作用包括气-固相互摩擦、颗粒间碰撞、聚并等行为的控制,随着颗粒循环速率的增大,提升管内颗粒间相互作用如颗粒间碰撞及颗粒聚并等发生频次升高,压力波动程度增强。随着提升管轴向位置的升高,压力信号波动程度逐渐减弱,其中在接近提升管顶部充分发展区域功率谱的低频高能现象基本消失。以上结果表明,在提升管底部区域气-固间的相互作用较强,引起压力波动程度较大,而充分发展区域内的气-固间相互作用处于稳定状态,压力波动较弱。

Studies on the gas-solids flow characteristics using power spectral density based on the pressure data from different axial locations in a riser of diameter in 80 mm and height in 18 m.Results show that the pressure signal fluctuation is mainly affected by gas-solid interaction, which included gas-solid friction, particle-particle collision and particle-particle aggregation. With the increase of solid circulating rate, frequency of particle interactions including particle-particle collision and particle-particle arrogation becomes strong and the pressure fluctuation also increases. It can be seen that the pressure signal fluctuation intensity decreased gradually with the increase of axial position in the riser. The phenomenon of low frequency with high power nearly disappears in the fully developed zone near the top of the riser. Based on the results,it can be concluded that the gas-solids interaction is stronger at the bottom of riser. On the other hand, the gas-solid interaction is more homogeneous, and the pressure fluctuation is relatively weak in the fully developed zone.