Interactions between two in-line drops rising in pure glycerin  

作　　者：Li Rao Zhengming Gao Ziqi Cai Yuyun Bao 

机构地区：[1]State Key Laboratory of Chemical Resource Engineering,School of Chemical Engineering,Beijing University of Chemical Technology

出　　处：《Chinese Journal of Chemical Engineering》2016年第10期1325-1334,共10页中国化学工程学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(21376016,21506005)

摘　　要：The behaviors of time-dependent interaction between two buoyancy-driven in-line deformable drops rising in pure glycerin at Re 〈 1 were studied, where the diameter for the leading drops ranged from 9.51 mm to 12.6 mm and for trailing drops from 12.7 mm to 15.8 mm. The situation while a larger drop chasing a smaller one was specifically considered which typically led to the smaller drop ＂coating＂ the larger one. Two approaches, the geometric feature approach and the energy change one, were used to judge the starting and ending times of the interaction between two drops. Based on a conical wake model, the drag coefficient of two approaching drops was calculated. Due to the approaching effect of the trailing drop, the leading drop was accelerated and the average drag coefficient was smaller than that for a free rising single drop. The frequency spectrums of the lateral oscillation of two drops during the interaction were obtained by using Fourier analysis. The oscillation frequency of the interactional drops was also different from that for a free rising single drop because of the wake effect produced by the leading drop. Due to a superposition of the drop shape oscillation and the drop internal circulation, the transverse oscillation frequencies of two drops have the same trend during the approaching process.The behaviors of time-dependent interaction between two buoyancy-driven in-line deformable drops rising in pure glycerin at Re b 1 were studied,where the diameter for the leading drops ranged from 9.51 mm to12.6 mm and for trailing drops from 12.7 mm to 15.8 mm.The situation while a larger drop chasing a smaller one was specifically considered which typically led to the smaller drop "coating" the larger one.Two approaches,the geometric feature approach and the energy change one,were used to judge the starting and ending times of the interaction between two drops.Based on a conical wake model,the drag coefficient of two approaching drops was calculated.Due to the approaching effect of the trailing drop,the leading drop was accelerated and the average drag coefficient was smaller than that for a free rising single drop.The frequency spectrums of the lateral oscillation of two drops during the interaction were obtained by using Fourier analysis.The oscillation frequency of the interactional drops was also different from that for a free rising single drop because of the wake effect produced by the leading drop.Due to a superposition of the drop shape oscillation and the drop internal circulation,the transverse oscillation frequencies of two drops have the same trend during the approaching process.

关 键 词：Two in-line drops Oscillation Fourier analysis Energy analysis 

分 类 号：TQ021[化学工程]