Preventing Explosions: How do Powder Flows Electrify?

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The electrification of powder flows is one of the most pervasive phenomena in environmental processes and of tremendous importance for technical applications. In industrial plants, excessive electrostatic charges can even lead to hazardous sparks, which have caused numerous catastrophic dust explosions in the past. However, despite its long history of investigation, it is not currently possible to predict the buildup, transport, and accumulation of charge. Starting from 2015, I developed a numerical approach with the important capability to couple the involved scientific disciplines – fluid mechanics (turbulent carrier flow), surface science (triboelectric particle charging), and electrostatics (forces between charges). The first ever fully-resolved simulations revealed that the occurrence of distinct physical flow mechanisms determines the charging rate of powder. This knowledge opens a new way to control the electrification through triggering these mechanisms and, thus, to solve the problem finally. To this end, this proposal aims to develop a novel interdisciplinary computational tool. This task includes establishing several new numerical concepts, such as a single-particle charging model. Beyond the state-of-the-art single-particle and powder flow electrification experiments which both employ innovative measurement methodologies will support the theoretical efforts. The proposed test set-ups will bring about a paradigm shift by quantifying, for the first time, reproducible, facility independent data, tailored specifically to complement the model formulation. The successful project will provide an open-source tool that enables the prediction, evaluation, and limitation of electrostatic charges. To this respect, the research aims not only to prevent accidents in industrial facilities but also to understand the physics of other kinds of electrifying powder flows and to solve a long-standing scientific riddle.