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| Gastar
- Dense gas dispersion model |
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GASTAR is now available to buy online, to see the pricing options and place your order go to the buy online page. GASTAR is a dense gas dispersion code, developed by CERC, ideally suited to modelling safety, accident and emergency response scenarios featuring releases of flammable and toxic materials such as time-varying cryogenic spills, pipe fractures and multi-phase jets, sudden catastrophic tank failure. In addition to standard features, such as continuous and instantaneous releases and momentum jet sources, dense and neutral releases, GASTAR includes many novel features, such as the effects of terrain (variable slopes and ground roughness) and obstacles (fences and buildings, which may be porous), a pool uptake model, time-varying releases and a jet that may point in any direction. In general, other dispersion models only include a subset of these features. GASTAR is an integral (or “box”) model. Using a combination of conservation laws applied to the cloud, supplemented by semi-empirical relations derived from recent dispersion research, it calculates spatially-averaged properties of the cloud, and their variation with distance downwind, and then applies profiles to give the concentration at any point. Novel features, such as slopes and obstacles, are incorporated into the integral formulation. Efficient solution algorithms require only seconds to solve a typical problem. Results from GASTAR can be viewed graphically using the built-in graphic tool or in tabular form via the interface. Output from each run includes a summary of the input data and output for all calculated cloud properties at any specified time. Additionally, a wide range of derived output is available, such as concentration-time histories at any (x, y, z) location, and, as appropriate, characteristics of the LFL contour, flammable volume and mass, dose and toxic load. The application is simple to use, with a well-designed user-friendly Windows interface similar to other CERC models, simplifying input data entry and providing flexible examination of output. GASTAR is also supplied with a database of material properties for common toxic and flammable substances; further substances can be added by the user as required. GASTAR has participated in major validation exercises, such as those of Hanna et al.1 and SMEDIS2 . The comparative exercise of Hanna et al. showed GASTAR to be one of the best performers for the standard data sets in flat terrain; while in SMEDIS the model was able to simulate successfully data sets from a wide range of experiments, most featuring one or more of the complex effects of slopes, obstacles and aerosols. GASTAR is the dense release model of choice for the UK Health and Safety Executive. In addition, GASTAR has been used by consultants in studies, both in the UK and abroad, including LNG spills, flammable hydrocarbon waste jets and site safety planning. If you would like more information on GASTAR please e-mail us using the feedback form on the contacts page.
[1] Hanna,
S.R., Chang, J.C. and Strimaitis, D.G. 1993 Hazardous gas model evaluation
with field observations. Atmos. Environ. 27A, 2265-2285. |
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