Numerical modelling of the effects of vessel length-to-diameter ratio (L/D) on pressure piling

• Published in: Journal of loss prevention in the process industries 2021-05, Vol.70, p.104398, Article 104398
• Main Authors: Ogungbemide, Damilare, Clouthier, Martin P., Cloney, Chris, Zalosh, Robert G., Ripley, Robert C., Amyotte, Paul R.
• Format: Article
• Language: English
• Subjects: CFD; Coal; Dust explosion; Numerical modelling; OpenFOAM; Pressure piling
• ISSN: 0950-4230
• DOI: 10.1016/j.jlp.2021.104398

Pressure piling presents a major explosion hazard in interconnected process vessels. Pressure enhancement in the secondary vessel due to the acceleration of the flame through the connecting pipe can generate a disproportionately more violent explosion than would have been expected based on the concentration of dust in the secondary vessel. Pressure piling is a very complex phenomenon that is difficult to investigate through experimentation. Advanced computational fluid dynamics (CFD) modelling is a promising route to accurately account for all the complexities associated with pressure piling. In this paper, the current state of knowledge concerning pressure piling is presented. Further, the effects of varying the length-to-diameter ratio (L/D) of the primary vessel (Vessel 1) on pressure piling was investigated using numerical modelling. The volumes and volume ratio of the interconnected vessels were kept constant while the L/D of Vessel 1 was varied from 0.5 to 15. The simulations of coal dust explosion were performed using the coalChemistryFoam solver from OpenFOAM version 5.0.1. It is hoped that the findings from this study provide insight into the effects of the geometrical design of interconnected vessels, particularly L/D, on pressure piling. Additionally, this work has implications for the optimal placement of explosion isolation devices intended to actuate before the flame front and pressure escape to downstream vessels. •Pressure enhancement in the secondary vessel (relative to the primary vessel) increased with the L/D of the primary vessel.•High frequency oscillations were observed in the extremities of the primary vessels at elevatedL/D ratios.•The time to attain maximum pressure in the primary vessel is a power function of the L/D ratioof the vessel.•The magnitude of the high-pressure contact cone increased with increase in the L/D of theprimary vessel.•As the L/D ratio of the primary vessel increased, the flame speed in the duct decreased as a power function of L/D ratio.