变径组合提升管内压力脉动及其流型转变特性

采用变径组合提升管冷模实验装置,在固/气比(Gs/(ρg·Ug))为0~37.60,通过实验对变径组合提升管内的压力脉动信号及其流型转变特性进行了研究。结果表明,随着固/气比(Gs/(ρg·Ug)的增加,变径组合提升管内依次出现气力输送(Gs/(ρg·Ug)为0~15.00)、快速流态化(Gs/(ρg·Ug)为15.00~27.00)、高密度循环流态化(Gs/(ρg·Ug)为2700~3760)3种流型。变径组合提升管内压力脉动主要由两部分组成：一部分是由于进料波动产生的全局性压力脉动,主频在0.30 Hz左右;另一部分是由于局部气流扰动,气-固相互作用以及颗粒(团)和颗粒(团)之间的相互作用引起的局部压力脉动。气力输送流型下,局部压力脉动的频率主要集中在D5频段(1.56~3.13 Hz),主要由局部气流扰动引起;快速流态化流型下,局部压力脉动的频率主要集中在D4频段(3.13~6.25 Hz),主要由局部气体与颗粒(团)间的作用引起;高密度循环流态化流型下,局部压力脉动的频率主要集中在D5频段,主要由局部颗粒(团)与颗粒(团)间的作用引起。

Characteristics of Pressure Fluctuation in Adjustable Combined Riser and Flow Regime Transition

With using an adjustable combined riser cold model experiment device and solid-gas ratio (Gs/(ρg·Ug)) ranging from 0 to 37.60, characteristics of both pressure fluctuation and flow regime transition were studied. Study results suggested that there were three kinds of flow regime in the riser, i.e, pneumatic conveying  (Gs/(ρg·Ug) 0-15.00), fast fluidization  (Gs/(ρg·Ug) 15.00-27.00), high-density circulating fluidization  (Gs/(ρg·Ug) 27.00-37.60). Pressure fluctuation in the adjustable combined riser is mainly composed of two parts: one is the global fluctuation caused by feed fluctuation, which is about 0.30 Hz at the main frequency; the other is local fluctuation caused by local air turbulence, gas solid interaction and clusters interaction. In the pneumatic conveying regime, the main frequency of local pressure fluctuation caused by the local air turbulence is concentrated in D5 (1.56-3.13 Hz) frequency. In the fast fluidization regime, the main frequency of local pressure fluctuation caused by the interaction between the local gas and particles (clusters) is concentrated in D4 (3.13-6.25 Hz) frequency. In the high-density circulating fluidization, the local pressure fluctuation caused by clusters interaction is concentrated in D5 frequency.