Lift and drag forces on an isolated cubic particle in pipe flow
Lift and drag forces on an isolated cubic particle in pipe flow
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DOI：
10.1016/j.cherd.2009.05.002
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发表时间：
2009-12-01
影响因子：
3.9
通讯作者：
Galvin, K. P.
中科院分区：
文献类型：
--
作者：
Laskovski, D.;Stevenson, P.;Galvin, K. P.
本文采用一种新的方法，其中使用了电磁铁，研究了所需的临界瞬时升力从圆柱形管壁的初始静止的磁性立方体的移动。电磁体用于控制磁性颗粒与管壁之间的接触力，实际上，通过将有效颗粒密度从1000 kg m（-3）改变到大于12，000 kg m（-3）。这种对有效颗粒密度的控制提供了一种简单且非侵入性的技术，用于确定在宽范围的流体速度下作用于立方颗粒的临界升力。选择立方体颗粒的尺寸大于von Karman的深度[von Karman T.，1930.机械原理和方法。蛾Phys. Klasse 5，58-76]检查的流体速度范围的粘性子层。从实验数据中推导出的临界瞬时升力导致Re <20，000的管道雷诺数的平均升力系数C（L）为3。壁面修正阻力系数C（Dw）为C（Dw）= 114 Re（p）（-0.8）CD（100 < Re（p）< 1000），用于计算临界升力，其中Re（p）为颗粒雷诺数，CD为阻力系数。在单独的实验中确定了上面给出的壁修正阻力系数相关性，在这些实验中，记录了立方体突然从管道拱腹释放后的水平位移。通过首先使用磁体将颗粒保持在适当位置，然后快速移除磁体来实现释放。本文似乎是第一个非侵入性地评估临界瞬时升力作用在一个特定的立方颗粒在管壁在很宽的范围内的表观流体速度。皇冠版权所有（C）2009由Elsevier B. V.代表化学工程师学会出版。All rights reserved.
In this paper, the critical instantaneous lift force required to move an initially stationary magnetic cube from the wall of a cylindrical pipe was examined using a novel method in which an electromagnet was employed. The electromagnet was used to control the contact force between the magnetic particle and the pipe wall by, in effect, varying the effective particle density from 1000 kg m(-3) to More than 12,000 kg m(-3). This control over the effective particle density provided a simple and non-intrusive technique of determining the critical lift force acting on the cubic particle for a broad range of fluid velocities. The cubic particle was chosen to be greater in size than the depth of the von Karman [von Karman T., 1930. Mechanische ahnlichkeit und turbulenz. Moth. Phys. Klasse 5, 58-76] viscous sub-layer for the range of fluid velocities examined. Critical instantaneous lift forces deduced from the experimental data resulted in an average lift coefficient, C(L), of 3 for pipe Reynolds numbers of Re < 20,000. A wall-corrected drag coefficient, C(Dw), of C(Dw) = 114 Re(p)(-0.8) CD for 100 < Re(p) < 1000 was used to calculate the critical lift force, where Re(p) is the particle Reynolds number and CD the drag coefficient. The wall-corrected drag coefficient correlation given above was determined in separate experiments in which the horizontal displacement of the cube, after its sudden release from the soffit of the pipe, was recorded. The release was achieved by firstly holding the particle in position using a magnet and then rapidly removing the magnet. This paper appears to be the first to non-intrusively evaluate the critical instantaneous lift force acting on a specific cubic particle at the pipe wall over a broad range of superficial fluid velocities. Crown Copyright (C) 2009 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved.