CFD Simulation of the Dispersion of Binary Dust Mixtures in the 20 L Vessel |
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Institution: | 1. Beijing Institute of Technology School of Mechatronical Engineering, Beijing 100081, China;2. Key Laboratory of Modern Measurement & Control Technology of Education, Beijing Information Science and Technology University, Beijing 100192, China;3. Xi''an Institute of Electromechanical Information Technology, Xi''an 70065, China |
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Abstract: | There are at least two main requirements for repeatable and reliable measurements of flammability and explosibility parameters of dusts: a uniform dispersion of solid particles inside the test vessel, and a homogeneous degree of turbulence. In several literature works, it has been shown that, in the standard 20 L sphere, the dust injection system generates a non-uniform dust cloud, while high gradients characterize the turbulent flow field. In this work, the dust dispersion inside the 20 L sphere was simulated for nicotinic acid/anthraquinone mixtures (with different pure dust ratios, while keeping the total dust concentration constant) with a validated three-dimensional CFD model. Numerical results show that the fields of dust concentration, flow velocity and turbulence are strongly affected by both diameter and density of the pure dusts. These different dust properties lead to segregation phenomena with the formation of zones richer in one component and leaner in the other one and vice versa, and also result in preferential paths for the solid particles inside the sphere. Overall, the obtained results highlight the need for developing a dust injection system able to overcome the shortcomings of the actual one even when testing dust mixtures. |
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Keywords: | CFD simulation Dust mixtures Dust dispersion Dust density Dust diameter Siwek sphere |
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