Numerical simulation of micro-bubble drag reduction using population balance model
Numerical simulation of micro-bubble drag reduction using population balance model
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DOI：
10.1016/j.oceaneng.2009.05.001
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发表时间：
2009-08-01
影响因子：
5
通讯作者：
Chen, L.
中科院分区：
文献类型：
--
作者：
Mohanarangam, K.;Cheung, S. C. P.;Chen, L.
使用欧拉-欧拉双流体模型研究了通过将微气泡注入湍流边界层来减少阻力的现象。基于群体平衡模型的多尺寸组（MUSIG）已用于此目的，该模型考虑了气泡破裂和合并，解决了各种气泡尺寸。将模拟结果与 Madavan 等人的实验结果进行比较。 [1984。通过微泡减少湍流的皮肤摩擦。流体物理学 27, 356-363] 以及其他解释减阻复杂现象的数值研究。对于所考虑的两种雷诺数情况，研究了底部配置的板的浮力，因为从实验中可以看出，浮力似乎在减阻中发挥了作用。研究中采用的数值模型包括充满微气泡的流动，其中使用两组独立的雷诺平均纳维斯托克斯 (RANS) 输运方程来描述流动的两个阶段。剪切应力输运 (SST) 湍流模型用作主相的湍流闭合，零方程湍流模型用于微气泡。提出并讨论了平均流向速度分布、空隙率、湍流修正和其他结果的变化以及气体注入速率的相应变化。根据我们的数值研究结果，对减阻的复杂机制进行了仔细检查和解释。还特别关注了随机碰撞和湍流冲击引起的气泡合并和破裂的影响。数值结果表明，在不同的空气注入速率下，表面摩擦系数与实验数据具有良好的一致性。人们发现 MUSIC 模型是解决微气泡引起的减阻问题中气泡动力学的最佳候选模型之一。 (C) 2009 Elsevier Ltd. 保留所有权利。
The phenomenon of drag reduction by the injection of micro-bubbles into turbulent boundary layer has been investigated using an Eulerian-Eulerian two-fluid model. Multiple-size group (MUSIG) based on population balance models, which resolve a wide range of bubble sizes taking into account the bubble break-up and coalescence have been used for this purpose. The simulated results are compared against the experimental findings of Madavan et al. [1984. Reduction of turbulent skin friction by microbubbles. Physics of Fluids 27, 356-363] and also other numerical studies explaining the sophisticated phenomena of drag reduction. For the two Reynolds number cases considered, the buoyancy with the plate on the bottom configuration is investigated, as from the experiments it is seen that buoyancy seem to play a role in the drag reduction. Numerical model employed in the investigation comprises of a micro-bubble laden flow wherein two independent sets of Reynolds averaged Navier-Stokes (RANS) transport equations were used to describe both the phases of the flow. The shear stress transport (SST) turbulence model is used as the turbulent closure for the primary phase and a zero equation turbulence model is used for the micro-bubbles. Change in the mean streamwise velocity profiles, void fraction, turbulence modification and other results are presented and discussed with corresponding change in the gas injection rates. The complex mechanism of drag reduction are scrutinised and explained in context to our numerical findings. Special attentions have been also devoted to divulge the effect of bubble coalescence and break-up caused by random collision and turbulent impact. Numerical results showed good agreement for the skin-friction coefficients against experimental data throughout various air injection rates. The MUSIC model was found to be one of the best candidates to resolve the bubble dynamics in micro-bubble-induced drag reduction problems. (C) 2009 Elsevier Ltd. All rights reserved.