排序方式: 共有9条查询结果,搜索用时 15 毫秒
1
1.
This paper presents an experimental study on the flow patterns of FCC particles in a 140 mm ID Circulating Fluidized Bed with concurrent upflow and downflow gas-solid suspension. Based on the distribution of local particle velocity and particle concentration measured by a Fiber-Optical Probe Laser Doppler Velocimeter and a Fiber Optical Probe System respectively, the different flow patterns of local particls concentration, local particle velocity, local particle fluctuating velocity and sectionally average particle velocity in concurrent upflow and downflow gas-solid system have been investigated. It is found that the particle flow in the concurrent downflow is much more uniform radially than that in the concurrent upflow riser. The investigation of flow patterns in different flow systems is of significance to the development of a new gas-solid reactor. 相似文献
2.
3.
4.
提升管循环流化床气,固局部滑落速度的分布 总被引:1,自引:0,他引:1
本研究采用光纤激光多普勒测速仪(LDV),通过两列信号处理系统,同时测定了气体和颗粒局部速度,研究了低密度循环流化床提升管内局部滑落速度的变化规律。实验结果表明,提高颗粒循环速率,在任一径向位置的气固滑落速度均增加;提高气体表观速度,反而使气固之间局部滑落速度减小。由于固体颗粒在近壁区的团聚行为,在近壁区气、固局部滑落速度出现一个极大值。 相似文献
5.
THE PARTICLE VELOCITY DISTRIBUTION IN A RISER OF DILUTE CIRCULATING FLUIDIZED BED 总被引:1,自引:0,他引:1 下载免费PDF全文
This paper presents an experimental study on the radial and axial profiles of local particle velocity of flu-idized catalyst(FCC)particles in a circulating fluidized bed of 8000mm in height and 186mm in inside diameterwith a Fiber-Optic Probe Laser Doppler Velocimetry.It has been found that the radial profiles of local particlevelocity are parabolic,even in the centre region and steep in the region near the bed wall,and that the length ofparticle acceleration along the bed height is longer than expected.The following formula has been recommended to correlate the 1 ocal particle velocity with dilute gas-solidflow in the bed:where a,b,c and e are functions of radial positions. 相似文献
6.
低密度循环流化床反应器床层截面平均颗粒速度的变化规律 总被引:4,自引:0,他引:4
本文在高8m,内径186mm 的循环流化床中采用 FCC 颗粒,利用 TSI 光纤激光多普勒测速仪测定了局部颗粒速度的径向分布,并获得了床层截面平均颗粒速度。实验结果表明:截面平均颗粒速度随操作气速的增大而增大,随固体循环速率的增大而略有减小。由实验数据回归得到了计算本实验条件下低密度速度的经验关联式。论文还从基本流体力学理论出发,在考虑颗粒加速运动的条件下,建立了一维气、固两相流模型,可以用于预测床层截面平均颗粒速度和空隙率的变化规律,模型计算结果和实验数据吻合较好。 相似文献
7.
低密度循环流化床局部颗粒速度的轴径向分布的研究 总被引:1,自引:0,他引:1
在高8m,内径186mm的循环流化床中,利用光纤激光多普勒测速仪测量了FCC颗粒的局部速度沿轴径向的分布。实验结果表明:局部颗粒速度沿径向分布是不均匀的,床中心区域分布比较平坦,近壁环形区域分布较陡,颗粒沿轴向运动有较长的加速段。由实验数据回归得到预测低密度循环流化床局部颗粒速度的经验关联式。 相似文献
8.
循环流化床下行管内气固两相流流体力学模型与数值模拟 总被引:2,自引:0,他引:2
从流体力学和湍流理论出发,将k-ε模型运用到气固两相流动体系中,建立了气固两相湍流模型。模型计算得出的轴径向颗粒浓度及速度与实测值相吻合,为下行管的设计放大提供了理论依据。 相似文献
9.
综述了循环流化床提升管和下行管气固两相流动模型研究的现状在对这些模型分类评述的基础上,给出了可用于描述下行管反应流动规律的一维两相和地维两相流动模型,为下行管反应器的设计,放在提供了理论依据。 相似文献
1