title: Numerical simulations of LNG vapor dispersion in Brayton Fire Training Field tests with ANSYS CFX.
abstract: Federal safety regulations require the use of validated consequence models to determine the vapor cloud dispersion exclusion zones for accidental liquefied natural gas (LNG) releases. One tool that is being developed in industry for exclusion zone determination and LNG vapor dispersion modeling is computational fluid dynamics (CFD). This paper uses the ANSYS CFX CFD code to model LNG vapor dispersion in the atmosphere. Discussed are important parameters that are essential inputs to the ANSYS CFX simulations, including the atmospheric conditions, LNG evaporation rate and pool area, turbulence in the source term, ground surface temperature and roughness height, and effects of obstacles. A sensitivity analysis was conducted to illustrate uncertainties in the simulation results arising from the mesh size and source term turbulence intensity. In addition, a set of medium-scale LNG spill tests were performed at the Brayton Fire Training Field to collect data for validating the ANSYS CFX prediction results. A comparison of test data with simulation results demonstrated that CFX was able to describe the dense gas behavior of LNG vapor cloud, and its prediction results of downwind gas concentrations close to ground level were in approximate agreement with the test data.
authors.affiliation: Mary Kay O'Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University System, College Station, TX 77843-3122, USA.
authors.forename: Ruifeng
authors.initials: R
authors.lastname: Qi
authors.forename: Dedy
authors.initials: D
authors.lastname: Ng
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Cormier
authors.forename: M Sam
authors.initials: MS
authors.lastname: Mannan
mesh_terms: D000059:Accidents; D000397:Air Pollution; D005390:Fires; D005716:Game Theory; D005740:Gases
chemical_list: D005740:Gases