Mechanics of Immersed Particle Collisions
Mechanics of Immersed Particle Collisions
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DOI：
10.1115/1.2821999
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发表时间：
1999-03
影响因子：
2
通讯作者：
R. Zenit;M. Hunt
中科院分区：
文献类型：
--
作者：
R. Zenit;M. Hunt
目前的工作使用简单的摆实验研究浸没在液体中的粒子碰撞的力学。使用高速数码相机测量水中不同颗粒的颗粒轨迹，并使用碰撞表面的高频响应压力传感器记录碰撞的强度。粒子减速发生在距离壁小于粒子直径一半的地方。测量到的碰撞脉冲随着冲击速度和颗粒质量的增加而增加。将测量的压力与假设完全弹性碰撞的基本冲击力学的预测进行比较。提出了一种考虑流体惯性和粘度的控制体积模型。当一个颗粒接近平面或另一个颗粒时，流体在接触之前受到挤压，从而降低了初始动能并使颗粒减速。对颗粒表面的压力分布进行积分，以获得力，该力是初始颗粒雷诺数 Reo 以及颗粒与流体相密度之比 ρp /ρf 的函数。该模型预测粒子以零速度到达壁的临界斯托克斯数。所提出的模型与实验测量之间的比较显示出定性的一致性。
The present work investigates the mechanics of particle collisions submerged in a liquid using a simple pendulum experiment. Particle trajectories for different particles in water are measured using a high-speed digital camera and the magnitude of the collision is recorded using a high-frequency-response pressure transducer at the colliding surface. The particle deceleration occurs at distances less than half a particle diameter from the wall. The measured collision impulse increases with impact velocity and particle mass. Comparisons are drawn between the measured pressures and the predictions of basic impact mechanics assuming a perfectly elastic collision. A control-volume model is proposed that accounts for the fluid inertia and viscosity. When a particle approaches a planar surface or another particle, the fluid is squeezed prior to contact, reducing the initial kinetic energy and decelerating the particle. The pressure profile is integrated over the surface of the particle to obtain a force that is a function of the initial particle Reynolds number, Reo , and the ratio of the densities of the particle and fluid phases, ρp /ρf . The model predicts a critical Stokes number at which the particle reaches the wall with zero velocity. Comparisons between the proposed model and the experimental measurements show qualitative agreement.