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The computed orientation distribution of fibers immersed in laminar pipe flows showed that the longitudinal distributions
are wide for small Reynolds numbers and become narrower with increasingRe. For lowRe number, the axial orientation distributions are broad with almost no preferred orientations. For highRe number, the axial distribution becomes narrow, with sharp maxima. The mean values of the longitudinal orientation depend
strongly on theRe number. The computed results are in qualitative agreement with relevant experimental results.
Project (No. 19925210) supported by the National Natural Science Foundation for Outstanding Youth of China 相似文献
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通过划分供水区域,控制分区供水服务压力,加强日常监测与动态测试以及局部供水管网的整合实现供水优化调度,有效控制多水源供水系统的管网压力。 相似文献
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薛雷 《福建工程学院学报》2008,6(3):205-208
根据在直角坐标系下建立的旋转直管内的流体流动方程,采用Galerkin 方法编写了相应的数值计算程序,然后对不同Re数和Ro数条件下的管内层流流动进行了求解,从而基于Galerkin 方法的特点获得了问题的高阶半解析解,有效地克服了摄动解的小参数局限.最后,研究了对圆截面正交旋转直管内的二次流动特性. 相似文献
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INTRODUCTIONThemotionoftheflowinarotatingcurvedpipeisafundamentalproblem ,whosesolutionhaspotentialapplicationsingasturbines ,elec tricgenerators ,electricmotorsandsomeequip mentsusedinseparationprocesses.Itisimpor tanttoknowtheflowstructurecharacteristic… 相似文献
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The low frequency oscillatory flow in a rotating curved pipe was studied by using the method of biparameter perturbation.
Perturbation solutions up to the second order were obtained and the effects of rotation on the low frequency oscillatory flow
were examined in detail. The results indicated that there exists evident difference between the low frequency oscillatory
flow in a rotating curved pipe and in a curved pipe without rotation. During a period, four secondary vortexes may exist on
the circular cross-section and the distribution of axial velocity and wall shear stress are related to the ratio of the Coriolis
force to centrifugal force and the axial pressure gradient.
Project (No: 10272096) supported by the National Natural Science Fundation of China 相似文献
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为了探索油气在冷凝回收过程中的冷凝规律,采用气液两相流模型描述了油气在竖直管内湍流流动时的冷凝过程.采用有效传质系数描述了油气组分的质量传递.模拟了油气在管内冷凝时的温度、管内压力、液膜厚度和Nusselt数的变化,得到了入口油气和管壁的温差、雷诺数对冷凝率和Nusselt数的影响.结果显示:增大入口雷诺数能显著增强传热和冷凝,但是增大入口油气和管壁的温差对冷凝率的影响较小;另外,还发现传质阻力对油气冷凝率有较大影响.此模型的计算结果与先前的实验数据能够很好地符合. 相似文献
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《中国科技论文》2019,(6)
针对旋转变径圆管内螺旋流场激光多普勒测速(laser Doppler velocimetry,LDV)存在的窗口振动、光束难聚焦与旋转多普勒效应等问题,设计了同轴双带驱动LDV实验装置。采用折射率匹配和光路计算相结合的方法,实现了其速度场的二维LDV测量,得到了不同壁面旋转率下变径圆管内螺旋流的切向、轴向速度分布。实验结果表明:旋转与螺旋流同向时,切向速度明显增加,最大切向速度随旋转率的增加率约为10%/N,最大切向速度点向边壁移动;当旋转率与螺旋流自身旋转率接近时,外涡流区几乎消失;旋转与螺旋流反向时,切向速度随之减小,最大切向速度随旋转率的减小率约为8%/N,最大切向速度点向轴心移动;不论壁面正反旋转,近壁区轴向速度都产生了层流化的趋势。 相似文献