双层桨自吸式反应器的气含率特性

考察了下层桨型式及结构尺寸对双层桨自吸式反应器内气含率(ε)的影响,为研究氧传质系数提供理论指导。实验结果表明,六直叶圆盘桨+六叶上斜叶桨组合在输入功率相同时,吸气速率较大,ε较高,可以促进气液传质。ε随下层桨安装高度(L_3)、下层桨桨叶角度(θ)、下层桨叶片长度(L/D)、下层桨叶片宽度(W/D)的增大而减小,即当L_3=0.05 m,θ=30°,L/D=0.125,W/D=0.2时,下层桨具有较高的泵送效率和气体分散能力,可以提高氧传质系数。ε的关联式为ε∝L_3^-0.11θ^-0.56(L/D)^-0.62(W/D)^-0.26,对于预测氧传质系数的主要影响因素具有重要的参考作用。

Characteristics of gas holdup in double-impeller self-inspirating reactor

In order to provide theoretical guidance for the study of oxygen mass transfer coefficient in a double-impeller self-inspirating reactor,the effects of lower impeller type and structure dimension on gas holdup(ε) were investigated. The results showed that the impeller combination of six straight blades disc turbine(6SBDT)+six pitched blades upflow turbine(6PBUT) has higher rate of gas induction at the same input power,therefore,it has a higher ε and can promote the gas-liquid mass transfer. The ε decreases with increases of the installing height(L3),blades angle(θ),blades length(L/D) and blades width(W/D) of the lower impeller,that is,when L3=0.05 m,θ=30°,L/D=0.125,W/D=0.2, the lower impeller has higher pumping efficiency and gas dispersing ability,thus oxygen mass transfer coefficient can be promoted. The correlation of the ε is ε∝ L3^-0.11θ^-0.56(L/D)^-0.62(W/D)^-0.26,which is an important reference for predicting the main influencing factors of the oxygen transfer coefficient.