Bolus contaminant dispersion for oscillatory flow in a curved tube.
Bolus contaminant dispersion for oscillatory flow in a curved tube.
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用于弯曲管中振荡流的团注污染物分散。
DOI：
10.1115/1.2796015
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Grotberg,JB
中科院分区：
文献类型：
--
作者：
Jiang,Y;Grotberg,JB
研究了体积循环振荡流期间可溶性污染物团在弯管中的分散情况。假设 δ（管半径与曲率半径之比）较小，则使用微扰法求解纳维-斯托克斯方程。然后通过根据横截面平均浓度及其轴向导数扩展局部浓度来求解对流扩散方程。时间平均无量纲有效扩散率 <Deff/D> 是针对一定范围的沃默斯利数 α 以及不同的行程幅度 A 和施密特数 Sc 值计算的，其中 D 是污染物的分子扩散率。对于所考虑的参数值，结果表明，弯管中的轴向色散大于直管中的轴向色散，并且对于给定的固定值 Sc = 1、A = 5 和 δ = 0.3，它在 α = 5 附近具有局部最大值。最后，演示了如何使用固定轴向位置处浓度的时间历史来确定有效扩散率。
The dispersion of a bolus of soluble contaminant in a curved tube during volume-cycled oscillatory flows is studied. Assuming a small value of δ (the ratio of tube radius to radius of curvature), the Navier-Stokes equations are solved by using a perturbation method. The convection-diffusion equation is then solved by expanding the local concentration in terms of the cross-sectionally averaged concentration and its axial derivatives. The time-averaged dimensionless effective diffusivity, 〈Deff/D〉, is calculated for a range of Womersley number α and different values of stroke amplitude A and Schmidt number Sc, where D is the molecular diffusivity of contaminant. For the parameter values considered, the results show that axial dispersion in a curved tube is greater than that in a straight tube, and that it has a local maximum near α = 5 for given fixed values of Sc = 1, A = 5 and δ = 0.3. Finally it is demonstrated how the time history of concentration at a fixed axial position can be used to determine the effective diffusivity.