Comprehensive review of multiphase flow dynamics and explosion mechanisms in hybrid combustible gas–deposited dust systems: From dust entrainment to secondary explosions

The explosion hazards associated with hybrid combustible gas–deposited dust systems have long been posing severe safety threats to powder-processing industries. Particularly, initial explosions triggering dust entrainment readily initiate chain reactions that induce secondary explosions. Given that secondary explosions exhibit long-range propagation, extensive destruction scales, and high unpredictability, they frequently cause catastrophic consequences far exceeding primary explosions. Based on comprehensive literature review, key multiphase flow dynamics and explosion mechanisms throughout the dust entrainment to shockwave-induced secondary explosion process are systematically synthesized. It systematically examines molecular diffusion kinetics in dust entrainment through three aspects: entrainment mechanisms, motion models, and particle transport principles. Additionally,summarize the dynamic prediction of dust concentration based on machine learning algorithms and the rapid quantification modeling of explosion parameters, while reviewing the frequency and characteristics of algorithm usage across various literature. Furthermore, by integrating experimental studies and numerical simulations, it reviews research advances in explosion pressure characteristics, flame propagation behaviors, gas-solid two-phase flow field evolution patterns, and microscopic explosion mechanisms. Results demonstrate that shock-induced dust entrainment stems from strongly coupled multiphysics interactions among fluid dynamics, particle mechanics, and shock waves. The explosion behavior of hybrid systems depends not only on inherent dust properties but also on complex flow-field environments governed by external shocks. Additionally, analysis of gas–solid coupled flow evolution reveals that flow-field structures directly determine dust cloud distribution and combustion efficiency, thereby dominating secondary explosion initiation. Finally, through microcharacterization and reaction pathway analysis, explosion mechanisms are contrasted using low-thermal-stability coal dust (pyrolysis-dominated) and high-thermal-stability aluminum dust (surface-oxidation-dominated). Concluding with current research findings, future critical challenges are outlined to refine theoretical frameworks for hybrid explosions, providing foundations for precise prevention/control of industrial explosion disasters and inherent safety enhancement.