Minimum spouting velocity of binary mixture with non-spherical particles

The minimum spouting velocity, U-ms, defined for stable external spouting, is found also crucial to ensure good mixing when multi-component particles are involved in spouted beds. In this study, experiments were performed in a cylindrical-conical spouted bed to study the influences of diverse factors on the U-ms of a binary system with the cylindrical particles and the spherical bed material. The results showed that the changes in U-ms with the particle properties (particle shape, size, and density) and operating conditions were closely related to the blending ratio of the mixture. When the volume fraction of the non-spherical particles was relatively small (less than 40% to 50%), U-ms mainly depended on the properties of the bed material. It was considered acceptable to estimate U-ms by assuming that the system only consisted of the spherical bed material. Otherwise, the cylindrical particle shape has a significant influence on the flow dynamics and U-ms. For such spouting systems, an equivalent diameter of the bed material was proposed to reflect the shape effects of non-spherical particles, whereby U-ms would be independent of the blending ratio. Consequently, a novel empirical correlation is proposed to quantitatively predict the U-ms of binary mixtures. (c) 2022 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Automated summary

In this study, the influences of diverse factors on the minimum spouting velocity (U-ms) of a binary system in a cylindrical-conical spouted bed were investigated. The results showed that U-ms was closely related to the particle properties, operating conditions, and blending ratio of the mixture. A novel empirical correlation was proposed to quantitatively predict U-ms in binary mixtures.