Determination of the explosion severity parameters of biomass is crucial for the safety management and dust explosion risk assessment of biomass-processing industries. These are commonly determined following experimental tests in the 20L sphere according to the international standards. Recently, CFD simulations have emerged as a reliable alternative to predict the explosion behavior with good accuracy and reduced labor and capital. In this work, numerical simulations of biomass dust explosions are conducted with the open-source CFD code OpenFOAM. The multi-phase (gas-solid) flow is treated in an Eulerian-Lagrangian framework, using a two-way coupling regime and considering the reactions of biomass conversion (moisture evaporation, devolatilization, and char oxidation), the combustion of volatile gases, and convective and radiative heat transfer. The model is validated with pressure-time and concentration-dependent experimental measurements of two biomass samples. Results suggest that the characteristics of the cold-flow (ı.e., turbulence levels, actual dust concentration, spatial distribution of the dust cloud, and turbophoresis effect) govern the course of the explosion process, and depend strongly on particle size, dust concentration, and ignition delay time effects. These findings may be relevant in the design of better dust explosion testing devices and to the reexamination of the guidelines for the operation of the experiment. Finally, a thorough discussion on the explosion pressures, degree of biomass conversion, flame temperature, flame propagation patterns, and the dust agglomeration effect is presented.

生物质爆炸烈度参数的确定对于生物质加工行业的安全管理和粉尘爆炸风险评估至关重要。这些通常是根据国际标准在 20L 球体中进行实验测试后确定的。最近，CFD 模拟已成为一种可靠的替代方法，可以准确地预测爆炸行为并减少劳动力和资本。在这项工作中，生物质粉尘爆炸的数值模拟是使用开源 CFD 代码 OpenFOAM 进行的。多相（气-固）流在欧拉-拉格朗日框架中进行处理，采用双向耦合机制并考虑生物质转化（水分蒸发、脱挥发分和焦炭氧化）反应、挥发性气体燃烧、以及对流和辐射传热。该模型通过两个生物质样品的压力-时间和浓度依赖性实验测量得到验证。结果表明，冷流的特性（即湍流水平、实际粉尘浓度、粉尘云的空间分布和涡流效应）控制着爆炸过程的过程，并且很大程度上取决于颗粒大小、粉尘浓度和点火延迟时间的影响。这些发现可能与设计更好的粉尘爆炸测试装置和重新审查实验操作指南有关。最后，对爆炸压力、生物质转化程度、火焰温度、火焰传播模式和粉尘团聚效应进行了深入讨论。