Effect of Fluid Forces on the Oblique Flow in a Vibrated Powder Bed

Katsuyuki Kominami, Yudai Sugiura, Yuki Tanikawa, Kenya Kuwagi

The 3rd International Symposium of Indonesian Chemical Engineering (ISIChem 2024)

The Institution of Engineers Indonesia (BKK-PII)

Bali, Indonesia

https://rsce2024.id/

It is known that a powder bed behaves like a liquid when vibrations are applied to it. By changing the vibration conditions, the flow patterns can vary significantly. A phenomenon where the surface of the upper layer of the powder bed becomes inclined can be observed under certain specific vibration conditions. The mechanism of this phenomenon is not sufficiently clarified. This inclined flow was simulated in numerical experiments by significantly increasing the viscous resistance. However, it is difficult to believe that such a large viscous drag occurs in the actual phenomenon. Other possible causes besides drag could include interactions with the fluid, such as added mass force and lubrication effects. Therefore, this study examined the influence of fluid dynamics on the particle motion using CFD-DEM simulations, which couple Computational Fluid Dynamics (CFD) with the Discrete Element Method (DEM). In the simulations, a single particle was placed in a rectangular container and allowed to free-fall, examining its motion as it rebounded off the bottom wall. As a result, the fluid forces acting on the particle increased with the narrowing of the container walls, and the simulation values were higher than the values calculated by using the Ergun equation or the formula by Cello. This difference was noticeable from the moment the particle began to fall, making it unlikely that the lubrication force, which acts when the inter-particle distance is small, had an effect. Therefore, it is possible that the added mass force could be a cause influencing such differences.