Documentation of AIR3D, an adaptation of the ground-water-flow code MODFLOW to simulate three-dimensional air flow in the unsaturated zone

Joss, Craig J.; Baehr, Arthur L.

doi:10.3133/ofr94533

Cited by 11 publications

(8 citation statements)

References 8 publications

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“…The next closest approximation available in Hazl is annealed glass which would require 2.7 kg TNT to break. Assuming 2.7 kg of TNT as a closer approximation, this value was taken as the input condition for modelling the secondary explosion using blast program Air3D [8]. Air3D is an open source code developed to simulate three dimensional air-flows in a heterogeneous, anisotropic zone.…”

Section: Overpressure Estimatementioning

confidence: 99%

Ignited releases of liquid hydrogen: Safety considerations of thermal and overpressure effects

Hall

Hooker

Willoughby

2014

International Journal of Hydrogen Energy

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a b s t r a c tIf the 'Hydrogen Economy' is to progress, more hydrogen fuelling stations are required. In the short term and in the absence of a hydrogen distribution network, these fuelling stations will have to be supplied by liquid hydrogen (LH2) road tankers. Such a development will increase the number of tanker offloading operations significantly and these may need to be performed in close proximity to the general public.The aim of this work was to determine the hazards and severity of a realistic ignited spill of LH2 focussing on; flammability limits of an LH2 vapour cloud, flame speeds through an LH2 vapour cloud and subsequent radiative heat levels after ignition. The experimental findings presented are split into three phenomena; jet-fires in high and low wind conditions, 'burn-back' of ignited clouds and secondary explosions7 post 'burn-back'. An attempt was made to estimate the magnitude of an explosion that occurred during one of the releases. The resulting data were used to propose safety distances for LH2 offloading facilities which will help to update and develop guidance for codes and standards.Crown

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Section: Overpressure Estimatementioning

confidence: 99%

Ignited releases of liquid hydrogen: Safety considerations of thermal and overpressure effects

Hall

Hooker

Willoughby

2014

International Journal of Hydrogen Energy

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“…The input to the vapor flow model includes the permeability fields developed with the geological uncertainty model and the NAPL saturation fields developed with the spill distribution model. Several approaches have been used to model vapor flow, including analytical models [Falta, 1995], adaptations of groundwater flow models [Massmann, 1989;Joss and Baehr, 1995], and numerical models developed specifically for gas flow [e.g., Rathfelder et al, 1991;Poulsen et al, 1996]. The vapor flow model used in this study is an adaptation of a steady state groundwater flow model.…”

Section: Vapor Flow Modelmentioning

confidence: 99%

Uncertainties in cleanup times for soil vapor extraction

Massmann¹,

Shock²,

Johannesen³

2000

Water Resources Research

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Abstract. Uncertainties in cleanup times for soil vapor extraction systems are estimated using mass removal curves generated through Monte Carlo analyses. The primary source of uncertainty is assumed to be soil permeability. Four general model components are coupled to quantify uncertainties: (1) a geological uncertainty model, (2) a spill distribution model, (3) a vapor flow model, and (4) a mass removal model. Spatial variability in permeability has a more significant effect on cleanup time than does overall average permeability because of the effects of channeling. For the examples considered in this study, field measurements of air conductivity have a relatively small effect on uncertainties in cleanup time. The examples also suggest that surface covers can significantly reduce cleanup time in cases where the extraction wells are not immediately within the zone of contamination and for relatively large spills. If wells are completed within the contaminated zone, however, these covers can actually increase average cleanup times. IntroductionSoil vapor extraction has become the most common innovative technology for treating subsurface soils contaminated with volatile and semivolatile organic compounds [U.S. Environmental Protection Agency, 1992]. This popularity is due, in part, to the low cost of vapor extraction relative to other available technologies, especially when contamination occurs relatively deep below the ground surface. Vapor extraction systems are also attractive because mitigation is completed in situ. This reduces the exposure of on-site workers and the off-site public to chemical contaminants. Vapor extraction also offers considerable flexibility in terms of installation and operation. This flexibility allows systems to be installed at crowded locations with existing structures, roadways, and other facilities and allows systems to be readily adjusted during the course of remediation to improve mass removal efficiency.Vapor extraction involves two major physical processes: mass transfer and mass transport. Mass transfer is the movement from one phase to another at a particular location. Volatile and semivolatile compounds will enter the vapor phase by desorption from the soil particles, through volatilization from the soil water, and by evaporation from nonaqueous phase liquids such as gasoline or liquid solvents. The rate at which this mass transfer occurs depends upon subsurface temperature, humidity, and pressure, the properties of the contaminant including vapor pressure and solubility, and the sorptive properties of the soil.The second major process involved in vapor extraction is mass transport, which is the movement of vapor from one location to another. This transport, which is primarily due to Copyright 2000 by the American Geophysical Union. Paper number 1999WR900305.0043-1397/00/1999WR900305509.00 advection, is caused by pressure gradients that are developed using extraction wells or trenches. In some instances, mass transport is enhanced through passive or active injection wells and...

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“…Baehr et al (1989) and Marley et al (1990) and others have used numerical solutions for systems with unsealed or partially sealed surfaces, and Lingineni and Dhir (1992) superimposed variable temperature on this approach. Joss and Baehr (1993) have recently adapted MODFLOW, a groundwater numerical modeling program, to SVE applications.…”

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confidence: 99%

Estimation of effective cleanup radius for soil‐vapor extraction systems

Sc.D.¹

1993

Journal of Soil Contamination

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Documentation of AIR3D, an adaptation of the ground-water-flow code MODFLOW to simulate three-dimensional air flow in the unsaturated zone

Cited by 11 publications

References 8 publications

Ignited releases of liquid hydrogen: Safety considerations of thermal and overpressure effects

Ignited releases of liquid hydrogen: Safety considerations of thermal and overpressure effects

Uncertainties in cleanup times for soil vapor extraction

Estimation of effective cleanup radius for soil‐vapor extraction systems

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