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90°细弯管内稀疏气固两相流动数值研究 被引量:3
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作者 胡霄乐 王维夫 谢剑舟 《轻工机械》 CAS 2015年第1期17-20,共4页
为了研究细弯管内稀疏气固流动条件下颗粒的分布特性,采用离散相模型(DPM)追踪颗粒行为,利用雷诺应力模型(RSM)模拟气相的湍流流动,考虑了流体-颗粒间的双向耦合作用。通过对颗粒和气体流动行为的分析,得到了气体压力、速度及颗粒浓度... 为了研究细弯管内稀疏气固流动条件下颗粒的分布特性,采用离散相模型(DPM)追踪颗粒行为,利用雷诺应力模型(RSM)模拟气相的湍流流动,考虑了流体-颗粒间的双向耦合作用。通过对颗粒和气体流动行为的分析,得到了气体压力、速度及颗粒浓度等的分布,研究了细弯管内颗粒流动行为的形成机理。结果表明:细弯管内气相压力沿流动方向逐渐降低;弯管段内气相最大速度沿管外壁分布;水平段颗粒作下沉运动,弯管段颗粒浓度先分两束,后成单束贴壁流动,最终杂乱分束,在竖直段彻底弥散化,这是由于各管段不同主要作用力所导致。 展开更多
关键词 细弯管 气固流动 离散相模型 分束流动
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On the structural features of fiber suspensions in converging channel flow 被引量:6
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作者 林建忠 张凌新 《Journal of Zhejiang University Science》 EI CSCD 2003年第4期400-406,共7页
The structural features of fiber suspensions are dependent on the fiber alignment in the flows. In this work the orientation distribution function and orientation tensors for semi-concentrated fiber suspensions in ... The structural features of fiber suspensions are dependent on the fiber alignment in the flows. In this work the orientation distribution function and orientation tensors for semi-concentrated fiber suspensions in converging channel flow were calculated, and the evolutions of the fiber alignment and the bulk effective vis-cosity were analyzed. The results showed that the bulk stress and the effective viscosity were functions of therate-of-strain tensor and the fiber orientation state ; and that the fiber suspensions evolved to steady alignment and tended to concentrate to some preferred directions close to but not same as the directions of local stream-lines. The bulk effective viscosity depended on the product of Reynolds number and time. The decrease of ef-fective viscosity near the boundary benefited the increase of the rate of flow. Finally when the fiber alignment went into steady state, the structural features of fiber suspensions were not dependent on the Reynolds numberbut on the converging channel angle. 展开更多
关键词 Fiber suspensions Orientation distribution Effective viscosity Converging channel flow
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Analysis of the nonlinear dynamic characteristics of two-phase flow based on an improved matrix pencil method
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作者 Hongwei Li Junpeng Liu +1 位作者 Yunlong Zhou Bin Sun 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第6期737-748,共12页
Gas–liquid two-phase flow is complex and has uncertainty in phase interfaces, which make the two-phase flow look very complicated. Even though the flow behavior(e.g. coalescence, crushing and separation) of single bu... Gas–liquid two-phase flow is complex and has uncertainty in phase interfaces, which make the two-phase flow look very complicated. Even though the flow behavior(e.g. coalescence, crushing and separation) of single bubble or bubble groups in the liquid phase looks random, combining some established characteristics and methodologies can find regularities among the randomness. In order to excavate the nonlinear dynamic characteristics of gas–liquid two-phase flow, the authors developed an improved matrix pencil(IMP) method to analyze the pressure difference signals of the two-phase flow. This paper elucidates the influence of signal length on MP calculation results and the anti-noise-interference ability of the MP method. An IMP algorithm was applied to the fluctuation signals of gas–liquid two-phase flow to extract the mode frequency and damping ratio, which were combined with the component energy index(CEI) entropy to identify the different flow patterns. It is also found that frequency, damping ratio, CEI entropy and stability diagram together not only identify flow patterns, but also provide a new way to examine and understand the evolution mechanism of physical dynamics embedded in flow patterns. Combining these characteristics and methods, the evolution of the nonlinear dynamic physical behavior of gas bubbles is revealed. 展开更多
关键词 Matrix pencil (MP) methodComponent energy index (CEI)Stability diagramFlow pattem identificationFlow dynamics
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Incorporating boundary constraints to predict mean velocities in turbulent channel flow 被引量:4
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作者 WU You CHEN Xi +1 位作者 SHE ZhenSu HUSSAIN Fazle 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第9期1691-1695,共5页
We derive exact near-wall and centerline constraints and apply them to improve a recently proposed LPR model for finite Reynolds number(Re) turbulent channel flows.The analysis defines two constants which are invarian... We derive exact near-wall and centerline constraints and apply them to improve a recently proposed LPR model for finite Reynolds number(Re) turbulent channel flows.The analysis defines two constants which are invariant with Re and suggests two more layers for incorporating boundary effects in the prediction of the mean velocity profile in the turbulent channel.These results provide corrections for the LPR mixing length model and incorrect predictions near the wall and the centerline.Moreover,we show that the analysis,together with a set of well-defined sensitive indicators,is useful for assessment of numerical simulation data. 展开更多
关键词 TURBULENCE channel flow mean velocity asymptotic analysis
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