Internal congestion can substantially affect vented dust-explosion loads, yet aggregate porosity does not describe how obstructed regions are spatially distributed. This study investigates the numerical sensitivity of explosion overpressure to obstacle porosity and spatial arrangement using a FLACS-CFD DustEx framework previously calibrated against an unobstructed experimental reference. Fifteen simulations were conducted for a centrally ignited maize-starch cloud in a vented enclosure, comparing an unobstructed configuration with two continuous rack-like and twelve discrete palletized regions of equal gross obstacle volume. Prescribed porosity ranged from 0 to 0.9; at each matched porosity, both layouts had identical fluid-accessible volume and initial dust mass. The unobstructed case produced a maximum monitored overpressure of 0.341 bar(g). At porosities of 0.4–0.9, maximum overpressures ranged from 0.325 to 0.493 bar(g) for racks and from 0.451 to 0.586 bar(g) for pallets, with pallet values 18.9–38.8% higher at equal porosity. In contrast, for fully impermeable regions, the rack and pallet predictions were 0.383 and 0.252 bar(g), respectively. The rack–pallet ordering was consistent across maximum overpressure and maximum positive pressure-rise rate but reversed between impermeable and partially porous cases. Published experimental benchmarks support the FLACS/PDR methodology for selected obstructed gas-explosion conditions, while dust-explosion studies provide complementary evidence for the combustion modelling framework. The present application, based on idealized rack and pallet volumes with prescribed equal area and volume porosities, is methodologically supported but has not been directly validated against corresponding physical storage configurations. Accordingly, the calculated pressure differences represent internally consistent, model-dependent trends rather than experimentally confirmed severity rankings.
Numerical investigation of obstacle porosity and spatial arrangement in vented dust explosions: Comparison of distributed-porosity rack and pallet configurations
Pinna, F.;Zucca, M.;Stochino, F.
2027-01-01
Abstract
Internal congestion can substantially affect vented dust-explosion loads, yet aggregate porosity does not describe how obstructed regions are spatially distributed. This study investigates the numerical sensitivity of explosion overpressure to obstacle porosity and spatial arrangement using a FLACS-CFD DustEx framework previously calibrated against an unobstructed experimental reference. Fifteen simulations were conducted for a centrally ignited maize-starch cloud in a vented enclosure, comparing an unobstructed configuration with two continuous rack-like and twelve discrete palletized regions of equal gross obstacle volume. Prescribed porosity ranged from 0 to 0.9; at each matched porosity, both layouts had identical fluid-accessible volume and initial dust mass. The unobstructed case produced a maximum monitored overpressure of 0.341 bar(g). At porosities of 0.4–0.9, maximum overpressures ranged from 0.325 to 0.493 bar(g) for racks and from 0.451 to 0.586 bar(g) for pallets, with pallet values 18.9–38.8% higher at equal porosity. In contrast, for fully impermeable regions, the rack and pallet predictions were 0.383 and 0.252 bar(g), respectively. The rack–pallet ordering was consistent across maximum overpressure and maximum positive pressure-rise rate but reversed between impermeable and partially porous cases. Published experimental benchmarks support the FLACS/PDR methodology for selected obstructed gas-explosion conditions, while dust-explosion studies provide complementary evidence for the combustion modelling framework. The present application, based on idealized rack and pallet volumes with prescribed equal area and volume porosities, is methodologically supported but has not been directly validated against corresponding physical storage configurations. Accordingly, the calculated pressure differences represent internally consistent, model-dependent trends rather than experimentally confirmed severity rankings.
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