Dust explosion has been a constant threat to the physical working environment of the Swedish process industries which deal with combustible powders. Examples of such industries are pellets, paper, metal processing, food and feed, pharmaceuticals, and additive industries. This project aims at (i) development of physics-based and well-validated models which address the important combustion phenomena in dust explosions, (ii) development of a well-verified and an efficient numerical tool based on an open-source toolbox OpenFOAM for predicting consequences of dust explosions and (iii) simulation of large-scale dust explosions in the process industries. The project result improves the understanding of dust explosions, and it provides the process industries with a numerical tool for designing safer process plant regarding dust explosions.The model and code development were carried out in a step-by-step fashion. First, the so-called Flame Speed Closure (FSC) model for premixed turbulent combustion, was implemented into OpenFOAM. The implementation was verified against analytical solutions for 1-dimensional planar and 3-dimensional spherical turbulent flames. Second, the developed code including the model, i.e., FSCDustFoam, was validated against experimental data on corn starch dust explosion in a fan-stirred explosion vessel under well-controlled laboratory conditions. Third, the FSC model was extended by adapting the well-known experimental observations of the self-similarity of the flame acceleration to address large-scale industrial dust explosions. An excellent agreement between measurements of vented corn starch dust explosions in an 11.5 m3 vessel and the simulations using the extended the FSC model was obtained.In spite of the successful development of FSCDustFoam, challenges remain. Specifically, the current version of FSCDustFoam cannot address the effect of different shapes of vent openings on dust explosions. Nevertheless, FSCDustFoam is a promising tool to be applied and further developed to resolve the challenging reality regarding dust explosions in the Swedish process industries.
The authors would like to acknowledge AFA Försäkring for financial support of this project (grant number 180028). The computations were enabled by resources provided by the Swedish National Infrastructure for Computing (SNIC) at HPC2N partially funded by the Swedish Research Council through grant agreement no. 2018-05973 and RISE Simulation Lab. The SNIC projects SNIC2021-22-217, SNIC2021-5-185 and SNIC2021-22-821 are acknowledged. Åke Sandgren and Erik Andersson at HPC2N are specially acknowledged. The authors would like to acknowledge IND EX® for providing the real scale test data of the IND EX® research project “Influence of the Explosion Relief Device Geometry on its Venting Efficiency”.