TITLE:
An Assessment Capability for LNG Leaks in Complex Environments
AUTHORS:
Sydney D. Ryan, Robert C. Ripley
KEYWORDS:
All Hazards Planner, Atmospheric Gas Dispersion, Computational Fluid Dynamics, Urban Canopy Flow, Emergency Response, Geohazards, Health and Safety, Environmental Impact
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.6 No.6,
June
22,
2018
ABSTRACT: Pollutants may be introduced into urban or marine settings by various means
and could result in an adverse impact to public safety and the environment.
Therefore, it is important for emergency management personnel to understand
the potential risks and physical extents of a leaked substance, whether it
is toxic, flammable or explosive. Traditional tools for predicting the atmospheric
dispersion of leaked substances are quick and simple to use, but may
not adequately consider the effects of the built environment that includes
complex urban and terrain geometries. Alternatively, CFD methods have been
increasing in application; although, their superior accuracy is met with commensurate
manual effort. The All Hazards Planner is a fast, accurate gas dispersion
modelling tool for city and port environments, which employs a
full-physics CFD approach but automates the intensive manual effort. In this
work, a credible LNG leak from a 12-mm-diameter hole is modelled for two
hypothetical case studies: adjacent to an LNG tanker and between a cruise
ship and pier during bunkering. The LNG vapour flammability extents are
compared to an empirical model in the absence of geometry effects and are
contrasted with geometry effects to highlight the importance of the real environment.
The free-field extents are invariant, whereas the inclusion of geometry
is shown to reduce the flammability extents by spreading at the ground-level
and forcing the plume upwards.