Motion of Individual Bubbles Rising in a Swarm
Extensive literature exists on the motion of single bubbles and the behaviour of swarms of bubbles. This contribution describes work to track and reveal the motion of individual bubbles in a swarm.The technique is based on high speed cinematography and wacking of multiple moving objects.Image processing algorithms were implemented in Matlab to isolate and measure geometric properties of the bubbles in image sequences recorded at 2 ms interval; and these properties were compiled into a data structure. To track a bubble, the geometric properties and a matching criterion were applied on consecutive pictures to identify the bubble, The bubble trajectory was reconstructed from the data structure for the matched objects. The methodology is briefly described.The new technique was tested for bubbles produced at slot-type spargers (i.e., approximately 2-D swarms) in the presence of two frother types (strong and weak). Two observations are discussed: a)that bubble motion in a swarm describes a velocity-size relationship dictated by the dominant bubble size class; and b) that surfactant type influences bubble rise velocity for bubbles in the range 0.1mm to 4 mm. The latter suggests surface viscosity rather than surface immobilization determines bubble rise velocity.
Bubble swarm Bubble motion High speed cinematography Surfactant
C. A. Acu(n)a J.A. Finch
Chemical Engineering Department, Cat(o)lica del Notre University, Antofagasta, Chile. Department of Mining and Materials Engineering, McGill University, Canad(a)
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
888-901
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）