  This study presents CFD simulations of biomass dust explosions in a newly
developed experimental 1 m$^3$ silo apparatus with variable venting, designed
and fabricated to operate similarly to the explosivity test standards. The aim
of the study is to validate a CFD model under development and investigate its
capability to capture the transient effects of a vented explosion. The model is
based on OpenFOAM and solves the multiphase (gas-particle) flow using an
Eulerian-Lagrangian approach in a two-way regime. It considers the detailed
thermochemical conversion of biomass, including moisture evaporation,
devolatilization, and char oxidation, along with the homogeneous combustion of
gases, turbulence, and radiative heat transfer. The explosion is analyzed in
all stages, i.e., dust cloud dispersion, ignition, closed explosion, and vented
explosion. The results indicate excellent agreement between the CFD model and
experimental tests throughout the sequence. Our findings highlight the critical
role of particle size in dust cloud distribution and pre-ignition turbulence,
which significantly influences flame dynamics and the explosion itself. This
model shows great promise and encourages its application for future
investigations of biomass dust explosions in larger-scale geometries,
especially in venting situations that fall out of the scope of the NFPA 68 or
EN 14491 standards, and to help design effective safety measures to prevent
such incidents.
