双层桨自吸式反应器的气含率特性
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摘要
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~(-0.11)θ~(-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。
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(6 SBDT)+six pitched blades upflow turbine(6 PBUT) 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(L_3),blades angle(θ),blades length(L/D) and blades width(W/D) of the lower impeller,that is,when L_3=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∝L_3~(-0.11)θ~(-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.
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(6 SBDT)+six pitched blades upflow turbine(6 PBUT) 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(L_3),blades angle(θ),blades length(L/D) and blades width(W/D) of the lower impeller,that is,when L_3=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∝L_3~(-0.11)θ~(-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.
引文
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[2]刘庭耀.气-液两相搅拌釜流体行为的数值模拟研究[D].北京:北京科技大学,2017.
[3]丁程兵,陈迁乔,钟秦.三种湍流模型下搅拌釜内气含率特性的模拟[J].化工进展,2013,32(11):2569-2573,2578.
[4]肖欣,杨宁.基于EMMS模型的搅拌釜内气液两相流数值模拟[J].化工学报,2016,67(7):2732-2739.
[5]郭扬扬.搅拌槽转轮半径及安装高度对气-液两相流影响的数值模拟[D].西安:西安理工大学,2018.
[6]Laakkonen M,Honkanen M,Saarenrinne P,et al.Local bubble size distributions,gas-liquid interfacial areas and gas holdups in a stirred vessel with particle image velocimetry[J].Chem Eng J,2005,109(1):37-47.
[7]Xie Minghui,Xia Jianye,Zhou Zhen,et al.Flow pattern,mixing,gas holdup and mass transfer coefficient of tripleimpeller configurations in stirred tank bioreactors[J].Ind Eng Chem Res,2014,53(14):5941-5953.
[8]郝惠娣,朱娜,秦佩,等.单层桨气液搅拌釜的气液分散特性[J].石油化工,2014,43(6):669-674.
[9]范兵强,张洋,郑诗礼,等.气液搅拌体系中宏观气含率的预测[J].过程工程学报,2016,16(4):565-570.
[10]郑海飞.带盘管的搅拌釜内气含率、传热特性及其应用研究[D].杭州:浙江大学,2017.
[11]范芳怡.剪切变稀体系下宽粘度域搅拌器的气液分散及传质性能研究[D].杭州:浙江大学,2018.
[12]高勇,严彪,胡军,等.双层桨自吸式气液搅拌釜内的功率准数[J].石油化工,2018,47(3):259-264.
[13]高江超.自吸式反应器搅拌特性的实验研究和数值模拟[D].上海:华东理工大学,2016.