Flow of suspensions in pipelines(Part 2: Two Mechanisms of Particle Suspension)
Flow of suspensions in pipelines(Part 2: Two Mechanisms of Particle Suspension)
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DOI：
10.1002/cjce.5450460405
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发表时间：
1968-08
影响因子：
2.1
通讯作者：
C. A. Shook;S. M. Daniel;J. A. Scott;J. Holgate
中科院分区：
文献类型：
--
作者：
C. A. Shook;S. M. Daniel;J. A. Scott;J. Holgate
采用伽玛射线吸收技术，在0.972 x 3.976 in的水平通道中测量了悬浮在24-28、40-50和80-100目的沙粒和悬浮在100-150目的镍粒的分布。平均混合流速为4.24-12.61英尺/秒，平均无因次输运浓度为0.024-0.28时的横截面；根据这些数据，计算了涡旋扩散系数。颗粒的湍流悬浮出现在低浓度、小粒径（小于0.2 mm）和沉降速度/流动摩擦速度比小于0.2:1时；在这些限制之外，浓度分布明显偏离通常与湍流悬浮液相关的浓度分布，这可能是由于粒子相互作用。在控制浓度分布方程中的涡流扩散率与单相流体中动量和质量的涡流扩散率具有相同的数量级。高固体浓度被发现增加了流体的悬浮能力，而不是“抑制”湍流。研究结果可推广到圆管内固体浓度分布的预测。
The distributions of suspended 24-28, 40-50, and 80-100 mesh sand particles and of 100-150 mesh nickel particles were measured by a gamma-ray absorption technique in a horizontal channel with a 0.972 x 3.976 in. cross section at mean mixture flow velocities of 4.24-12.61 ft/sec and at average dimensionless transport concentrations of 0.024-0.28; from these data, the eddy diffusivities were calculated. Turbulent suspension of the particles appeared to occur at low particle concentrations, at small particle diameters (less than 0.2 mm), and at particle settling velocity/flow friction velocity ratios of less than 0.2:1; outside these limits the concentration profiles deviated significantly from those usually associated with turbulent suspensions, which could be due to particle interactions. The eddy diffusivity in the equation governing the concentration profiles was found to be of the same order of magnitude as the eddy diffusivities for momentum and mass in single-phase fluids. High solid concentrations were found to increase the suspending capacity of the fluid, rather than to "damp" the turbulence. The results of this study can be extended to predict the solids concentration distributions in circular pipes.