在冷态试验的基础上通过理论分析，说明了在催化裂化提升管反应器预提升段内，混合加速区、均匀加速区、充分发展区分别可以看作是三维流场、二维流场及一维流场。针对充分发展区提出了无量纲因数α表示径向密度分布的不均匀特征，并根据分析α的增减性，验证了采用增加气速、边壁注气、缩放形管技术可改善提升管径向密度分布的可行性 Based on the cold test, the theoretical analysis shows that in the pre-riser section of FCC riser reactor, the mixed accelerating zone, uniform accelerating zone and fully developed zone can be regarded as three-dimensional flow field, two-dimensional flow field and One-dimensional flow field. According to the analysis of the increase and decrease of α, it is verified that the increase of the diameter of the pipe can be improved by increasing the velocity of gas, The feasibility of density distribution