Research on the Motion of Particles in the Turbulent Pipe Flow of Fiber Suspensions
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摘要: 利用从细长体理论出发得到的三维分段积分法和湍流简化方法模拟了大量纤维粒子在圆管湍流内的运动．统计了不同Re数下计算区域内的纤维的取向分布，计算结果与实验结果基本吻合，结果表明湍流的脉动速度导致纤维取向趋于无序，且随着Re数的增加，纤维取向的分布越来越趋于均匀．其后又考虑了纤维速度和角速度的脉动，二者都充分体现了流体速度脉动的影响，且纤维速度的脉动在流向上的强度大于横向，而其角速度的脉动在流向上的强度小于横向．最后统计了纤维在管道截面上的位置分布，说明Re数的增加加速了纤维在管道截面上的位置扩散．Abstract: The motion of fibers in turbulent pipe flow was simulated by 3-D integral method based on the slender body theory and simplified model of turbulence.The orientation distribution of fibers in the computational area for different Re numbers was computed.The results which were consistent with the experimental ones show that the fluctuation velocity of turbulence cause fibers to orient randomly.The orientation distributions become broader as the Re numer increases.Then the fluctuation velocity and angular velocity of fibers were obtained.Both are affected by the fluctuation velocity of turbulence. The fluctuation velocity intensity of fiber is stronger at longitudinal than at lateral,while it was opposite for the fluctuation angular velocity intensity of fibers.Finally,the spatial distribution of fiber was give.It is obvious that the fiber dispersion is strenghened with the increase of Re numbers.
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Key words:
- fiber suspension /
- numerical simulation /
- pipe flow /
- turbulent /
- orientation
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[1] Batchelor G K.Slender-body theory for particles of arbitrary cross-section in Stokes flow[J].J Fluid Mech,1970,44(3):419—440. doi: 10.1017/S002211207000191X [2] Leal L G,Hinch E J.The effect of weak Brownian rotations on particles in shear flow[J].J Fluid Mech,1971,46(4):685—703. doi: 10.1017/S0022112071000788 [3] 林建忠，石兴，邵雪明，等.纤维悬浮混合层中纤维取向与流场应力的研究[J].自然科学进展，2002，12(4)：372—376. [4] 林建忠，林江，石兴.两相流中柱状固粒对流体湍动特性影响的研究[J].应用数学和力学，2002,23(5):483—488. [5] LIN Jian-zhong,ZHANG Wei-feng,WANG Ye-long.Research on the orientation distribution of fibers immersed in a pipe flow[J].Journal of Zhejiang University Science,2002,3(5):501—506. doi: 10.1631/jzus.2002.0501 [6] Bernstein O,Shapiro M.Direct determination of the orientation distribution function of cylindrical particles immersed in laminar and turbulent flow[J].J Aerosol Aci,1994,25(1):113—136. [7] Olson J A.The motion of fibres in turbulent flow,stochastic simulation of isotropic homogeneous turbulence[J].Int J Multiphase Flow,2001,27:2083—2103. doi: 10.1016/S0301-9322(01)00050-7 [8] WANG Lian-ping,Stock D E.Numerical simulation of heavy particle dispersion-scale ratio and flow decay considerations[J].J Fluids Eng Trans ASME,1994,116:154—163. doi: 10.1115/1.2910224 [9] Fung J C H,Hunt J C R,Malik N A,et al.Kinematic simulation of homogeneous turbulence by unsteady random Fourier modes[J].J Fluid Mech,1992,236:281—318. doi: 10.1017/S0022112092001423 [10] Laufer J.The structure of turbulence in fully developed pipe flow[J].Natl Advisory Comm Aeronaut Tech Repts,1954,1174:417—434. [11] Mackaplow M B,Shaqfeh E S G.A numerical study of the sedimentation of fibre suspension[J].J Fluid Mech,1998,376:149—182. doi: 10.1017/S0022112098002663 -
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