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A modelling and experimental study of the bubble trajectory in a non-Newtonian crystal suspension

หน่วยงาน Central Queensland University, Australia

รายละเอียด

ชื่อเรื่อง : A modelling and experimental study of the bubble trajectory in a non-Newtonian crystal suspension
นักวิจัย : Hassan, N. M. S. , Khan, Mohammad Masud Kamal. , Rasul, Mohammad.
คำค้น : Bubbles , Applied research. , 970109 Expanding Knowledge in Engineering. , 970110 Expanding Knowledge in Technology. , 090408 Rheology. , 090407 Process Control and Simulation. , 091399 Mechanical Engineering not elsewhere classified. , 091504 Fluidisation and Fluid Mechanics. , Fluid mechanics. , Crystals. , Bubble trajectory -- Volume of Fluid ( VOF) method -- CFD -- FLUENT
หน่วยงาน : Central Queensland University, Australia
ผู้ร่วมงาน : -
ปีพิมพ์ : 2553
อ้างอิง : http://hdl.cqu.edu.au/10018/55741
ที่มา : Hassan, NMS, Khan, MMS & Rasul, MG 2010, 'A modelling and experimental study of the bubble trajectory in a non-Newtonian crystal suspension', Fluid Dynamic Research, vol. 42, pp. 1-21, http://dx.doi.org/10.1088/0169-5983/42/6/065502
ความเชี่ยวชาญ : -
ความสัมพันธ์ : Fluid dynamics research. London, U.K. : The Japan Society of Fluid Mechanics and IOP Publishing Ltd, 2010. Vol. 42, (2010), p. 1-21 21 pages Refereed 0169-5983 1873-7005 , ACQUIRE [electronic resource] : Central Queensland University Institutional Repository.
ขอบเขตของเนื้อหา : -
บทคัดย่อ/คำอธิบาย :

This paper presents an experimental and computational study of air bubbles rising in a massecuite-equivalent non-Newtonian crystal suspension. The bubble trajectory inside the stagnant liquid of a 0.05% xanthan gum crystal suspension was investigated and modelled using the computational fluid dynamics (CFD) model to gain an insight into the bubble flow characteristics. The CFD code FLUENT was used for numerical simulation, and the bubble trajectory calculations were performed through a volume of fluid (VOF) model. The influences of the Reynolds number (Re), the Weber number (We) and the bubble aspect ratio (E) on the bubble trajectory are discussed. The conditions for the bubbles’ path oscillations are identified. The experimentalresults showed that the path instability for the crystal suspension was less rapid than in water. The trajectory analysis indicated that 5.76mm diameter bubbles followed a zigzag motion in the crystal suspension. Conversely, the smaller bubbles (5.76 mm) followed a path of least horizontal movement and larger bubbles (21.21 mm) produced more spiral motion within the crystal suspension. Path instability occurred for bubbles of 15.63 and 21.21mm diameter, and they induced both zigzag and spiral trajectories within the crystal suspension. At low Re and We, smaller bubbles (5.76 mm) produced a zigzag trajectory, whereas larger bubbles (15.63 and 21.21 mm) showed both zigzag and spiral trajectories at intermediate and moderately high Re and We in the crystal suspension. The simulation results illustrated that a repeating pattern of swirling vortices was created for smaller bubbles due to the unstable wake and unsteady flow of these bubbles. This is the cause of the smaller bubbles moving in a zigzag way. Larger bubbles showed two counter-rotating trailing vortices at the back of the bubble. These vortices induced a velocity componentto the gas–liquid interface and caused a deformation. Hence, the larger bubbles produced a path transition.

บรรณานุกรม :
Hassan, N. M. S. , Khan, Mohammad Masud Kamal. , Rasul, Mohammad. . (2553). A modelling and experimental study of the bubble trajectory in a non-Newtonian crystal suspension.
    กรุงเทพมหานคร : Central Queensland University, Australia.
Hassan, N. M. S. , Khan, Mohammad Masud Kamal. , Rasul, Mohammad. . 2553. "A modelling and experimental study of the bubble trajectory in a non-Newtonian crystal suspension".
    กรุงเทพมหานคร : Central Queensland University, Australia.
Hassan, N. M. S. , Khan, Mohammad Masud Kamal. , Rasul, Mohammad. . "A modelling and experimental study of the bubble trajectory in a non-Newtonian crystal suspension."
    กรุงเทพมหานคร : Central Queensland University, Australia, 2553. Print.
Hassan, N. M. S. , Khan, Mohammad Masud Kamal. , Rasul, Mohammad. . A modelling and experimental study of the bubble trajectory in a non-Newtonian crystal suspension. กรุงเทพมหานคร : Central Queensland University, Australia; 2553.