By analyzing solid holdup signals in the jet influence zone of risers, the characteristics of clusters were studied. The solid holdups inside clusters and their distribution ranges were calculated under the cases of both upward and downward feed jets. Moreover, the effects of the jet velocity on the cluster characteristics were analyzed. The solid holdups inside clusters have higher values and wider distribution ranges in the upward feed injection zone than in the downward zone, implying that the number of individual particles in a cluster is unstable under the influence of upward jets. For the case of downward jets, cluster formations in the jet influence zone of risers can more easily maintain stability, offering a better mixing environment for jets and particles. As the jet velocity increases, the solid holdups inside clusters in the riser wall of the upward injection zone increase accordingly, while the distributions of solid holdups inside clusters have no significant changes if the feed jets are downward. This phenomenon confirms that improved operational flexibility can be obtained if downward jets are mixed with the prelift gas–solid flow in risers.

通过分析立管射流影响区内的固体滞留信号，研究了团簇的特征。在向上和向下进料的情况下，计算了团簇内部的固体滞留量及其分布范围。此外，分析了射流速度对团簇特征的影响。团簇内部的固体滞留物在向上进料注入区比在下行区具有更高的值和更宽的分布范围，这意味着在上行射流的影响下，团簇中单个颗粒的数量不稳定。对于向下的射流，立管的射流影响区中的团簇形成可以更轻松地保持稳定性，从而为射流和颗粒提供更好的混合环境。随着射流速度的增加，向上喷射区的上升管壁中的团簇内部的固体滞留量相应增加，而如果进料口朝下，则团簇内部的固体滞留量分布没有明显变化。这种现象证实，如果向下的射流与提升管中的预举气固流混合，则可以提高操作灵活性。