中国环境科学
中國環境科學
중국배경과학
CHINA ENVIRONMENTAL SCIENCE
2014年
4期
951-957
,共7页
混凝%絮体形态%Taylor-Couette流场%PIV
混凝%絮體形態%Taylor-Couette流場%PIV
혼응%서체형태%Taylor-Couette류장%PIV
coagulation%flocs morphology%Taylor-Couette flow field%PIV
采用粒子成像速度场仪(PIV)对Taylor-Couette反应器内的混凝过程中絮体的微观形貌进行了观测与表征。结果表明,内筒转速在20~60r/min 范围内,生成的絮体颗粒较大,粒径分布均匀,絮凝沉淀效果最好。由于内筒旋转速度的变化直接导致混凝流场形态的变化,所以混凝过程中流场形态的变化对絮体生长过程有重要影响,进而直接影响到混凝效果。混凝过程中流场的周期性变化、涡间存在液体传递的波状涡结构有利于絮体颗粒的结合生长,并导致较高的絮凝沉淀去除率。这也说明 PIV 技术能够在测量流场的同时较好地反映混凝过程中微絮体的形貌变化特征,从而实现对絮凝过程的原位观测与表征。
採用粒子成像速度場儀(PIV)對Taylor-Couette反應器內的混凝過程中絮體的微觀形貌進行瞭觀測與錶徵。結果錶明,內筒轉速在20~60r/min 範圍內,生成的絮體顆粒較大,粒徑分佈均勻,絮凝沉澱效果最好。由于內筒鏇轉速度的變化直接導緻混凝流場形態的變化,所以混凝過程中流場形態的變化對絮體生長過程有重要影響,進而直接影響到混凝效果。混凝過程中流場的週期性變化、渦間存在液體傳遞的波狀渦結構有利于絮體顆粒的結閤生長,併導緻較高的絮凝沉澱去除率。這也說明 PIV 技術能夠在測量流場的同時較好地反映混凝過程中微絮體的形貌變化特徵,從而實現對絮凝過程的原位觀測與錶徵。
채용입자성상속도장의(PIV)대Taylor-Couette반응기내적혼응과정중서체적미관형모진행료관측여표정。결과표명,내통전속재20~60r/min 범위내,생성적서체과립교대,립경분포균균,서응침정효과최호。유우내통선전속도적변화직접도치혼응류장형태적변화,소이혼응과정중류장형태적변화대서체생장과정유중요영향,진이직접영향도혼응효과。혼응과정중류장적주기성변화、와간존재액체전체적파상와결구유리우서체과립적결합생장,병도치교고적서응침정거제솔。저야설명 PIV 기술능구재측량류장적동시교호지반영혼응과정중미서체적형모변화특정,종이실현대서응과정적원위관측여표정。
Particle image velocimetry (PIV) was applied to characterize and measure the morphological changes of the flocs during the coagulation process. The results indicated that the flocs particles were much bigger, their size distribution was more uniform, and the sedimentation efficiencies were higher when the rotation speed of the inner cylinder was in the range 20~60r/min. The rotation speed of the inner cylinder had a great influence on the flow field which directly affected the flocs size, morphology and coagulation efficiencies. The vortex flow field structure change with time periodically and the bulk fluid motion may be beneficial for the flocs to combine with each other and grow up, leading to the higher flocculation efficiency. This research demonstrated that the morphology of the flocs in the coagulation process can be characterized and described perfectly by PIV and PIV can be exploited as a useful tool in the in-situ observation and measurement during coagulation processes.