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添加聚合物对混合层流场特性影响的实验研究 总被引:1,自引:0,他引:1
叙述了适用于粘弹性流体混合层流场的实验装置的设计和研制.采用二维激光多普勒系统对混合层流场进行了测量,得到了平均速度剖面、动量厚度、湍流脉动强度、雷诺应力等一些流场的基本特征量.结果表明,混合层中加入聚合物后流场将有较大的变化,同时也说明本文所研制的实验装置满足实验的要求. 相似文献
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IntroductionTheMixinglayeriscommonlyencounteredinvariouschemicalprocesses .Itisthereforesignificanttostudythebehaviorsofcoherentstructuresinamixinglayerinordertopredictandcontroltheevolutionoftheflow ,thenimprovethemixingandchemicalreactionefficiency .S… 相似文献
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The numerical simulation with two-way coupling was performed in a liquid -particle mixing layer and the corresponding experiment study was made. In the process of vortex rolling up and vortices pairing, the particles with different St number have a very different pattern of dispersion. The mean velocity of particle with St = 1 is higher than that of the fluid phase on the low-speed side, and lower than that of the fluid phase on the high-speed side. The RMS of particle approaches that of the fluid phase with decreasing particle St number. The RMS in the transverse direction is smaller than that in the streamwise direction. The velocity fluctuation correlation of particle is smaller than the Reynolds shear stress, the “overshoot“ phenomenon that the velocity fluctuation correlation of particle is larger than the Reynolds shear stress does not appear. The larger the St number of particle is, the wider the range of the particle dispersion will be. The computed results are in agreement with the experimental ones. 相似文献
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FENE-P流体混合层中拟序结构的研究 总被引:1,自引:0,他引:1
采用FENE-P模型对高雷诺数下二维粘弹性混合过程中拟序结构的演变进行了数值研究.由于对聚合物应力场采用了适当的滤波措施,得到了较AH更宽参数范围内FENE-P流体混合层流场中拟序结构的运动特性,计算结果表明:在流场中加入聚合物,基波和次谐波的发展受到抑制,涡量扩散加强,减慢了配对时两涡核的旋转运动,这种影响随Weissenberg数的增大而减小,但却随参数b的增大而加强.另外,与相同溶液粘度下的牛顿流体相比,配对过程中涡量完全合并的时刻延迟了. 相似文献
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The sedimentations of two cylindrical particles in three different initial relative positions are numerically simulated using
the lattice Boltzmann method. The movement characteristics and particle interactions during their sedimentation are presented
and discussed in detail. The results show that, (i) if the two particles are released parallel but separated horizontally,
they push away each other, rotate inwards and separate horizontally as they fall; (ii) if the two particles are released parallel
but separated vertically, the sedimentation behavior can be classified into three stages: trailing, tumbling and separating;
(iii) if the two particles are released perpendicular but separated vertically, the sedimentation behavior can be characterized
as: trailing and rotating, touching and sliding. In order to validate our simulation, experiments were also conducted and
the results agree well with the numerical ones.
The project supported by the National Natural Science Foundation of China for Distinguished Scholars (19925210) 相似文献
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IntroductionParticulateflowsarecommonlyencounteredinvariousnaturalphenomenaandindustrialprocesses,suchasinthechemicalandpetroleumindustries,thesedimentationofparticlesisawayofseparatingparticlesfromfluid ,aswellasawayofseparatingparticleswithdifferentsettlingspeedsfromeachother[1].Animportantaspectoftheseflowsisparticlepairinteraction ,whichisfundamentalmechanismsthatenterstronglyintoallpracticalapplicationsofparticulateflows.Problemofthesedimentationoftwoequalparticleshasbeenpreviouslystudied… 相似文献
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虚拟边界法研究正交双圆柱及串列双圆球绕流 总被引:6,自引:0,他引:6
把Goldstein等人提出的虚拟边界法推广到三维情况,研究了
Re=150时不同间距下正交双圆柱绕流,和Re=250时不同间距下串列双
圆球绕流流场. 对于正交双圆柱绕流,当间距比大于3,下游圆柱对上游圆柱尾流的影响只
限定在下游圆柱的尾流所扫过的范围之内;当间距比小于等于3,下游圆柱对上游圆柱尾流
的影响扩大,下游圆柱尾流扫过区上下出现两排三维流向二次涡结构. 对于串列圆球绕流,
研究发现,在小间距比(L/D≈ 1.5)的情况下,由于上下游圆球尾流区的相互抑
制消除了压力不稳定性,整个流场呈现稳
态轴对称特征;间距比为2.0时,周向压力梯度诱发出流体的周向输运,流场呈现稳态非对
称性,但流场中存在特定的对称面;间距比增大到2.5后,绕流场开始周期振荡,原有的对
称面依旧存在;在间距比3.5时下游圆球下表面的涡结构强度有所减弱,导致占优频率发生
交替;间距比增至7.0时,整个流场恢复稳态特征,两圆球尾部同时出现双线涡,这时流场
对称面的位置发生了变动. 相似文献