Experimental and theoretical analysis of large particle\u2013wall collision with different metal plates

Xueyu Chen,Yi Li,Langyu Ji

doi:10.1007/s40430-022-03376-3

Xueyu Chen, Yi Li + Show 1 more

Open Access

https://doi.org/10.1007/s40430-022-03376-3

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Abstract

The coefficients of restitution are important parameters in the study of particle–wall collision, which is widely used in discrete element modeling in solid–liquid multiphase systems. To improve the accuracy of numerical simulations, correspondingly exact particle–wall collision parameters are needed. The current models used in numerical simulation, however, are mostly suitable for solid–gas systems, in which collision models used to be micro-sized. Millimeter-size particle–wall collision models in wet experimental conditions and research on the influence of plate materials were lacking. In this study, we designed an experimental system focused on the different materials of the particles and collision plates and the dry or wet experimental environment to discuss the change of restitution coefficients in various conditions. We selected millimeter-sized iron 45 particles and glass particles, which represented plastic material and hard brittle material, respectively. We also selected three industrial metals, HT250 gray cast iron, 6061 aluminum alloy, and 316 stainless steel, which are commonly used in hydraulic machinery, for the collision plates. Experiments were performed to measure the incident and rebound velocities of the particle at various impact angles. In this paper, we have provided and compared the results of restitution coefficients of velocity and angle varying with the approach angle. In the processing of the experiment, we used the control variate method and applied an ultra-depth of field three-dimensional microscope to scan the surface of the collision plate. In the analysis of the experimental results, single particle–wall collision was seen as a non-smooth dynamical system to discuss the specific phenomenon. Finally, we obtained the relationship between the restitution of normal velocity and elastic elements of materials and explained the relationship of stick–slip motion with the approach angle and velocity.

Highlights

Collision is a basic research object in the physical sciences, and it plays a key role in industrial processes like filtration, agglomeration, spray coating, and multiphase transmission
The results showed the changes trending in the coefficient of the restitution in the velocity and angle of iron particles and glass particles before and after the collision along with the impact angles from 10° to 90°, which were controlled by the oblique angles of the plate
There was a slight downward trend in the velocity curves when using the glass particles shown in Fig. 6c, and the velocity coefficients seemed to be dependent on the impact angles of the glass particles

Summary

Introduction

Collision is a basic research object in the physical sciences, and it plays a key role in industrial processes like filtration, agglomeration, spray coating, and multiphase transmission. For the simplification of study, the typical collision model, like a particle shot toward a random object, has been simplified to a specific plate. This kind of particle–wall collision model has provided a theoretical foundation that influences the accuracy of numerical simulations that involve. The first classical analysis was established by Hertz [1], who assumed perfectly elastic collisions in a normal direction and provided definitions of coefficients of restitution. Sommerfeld [5] studied the small particle–wall collision model and the relationships between the coefficient of restitution, surface roughness, rotating angular velocity of particles, and the coefficient of friction. A significant achievement was proposed by Grant et al [6], who put forward the first suitable particle–wall collision model for gas–solid two-phase flow

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Conclusion