GasDispersion.jl

GasDispersion.jl is a set of tools for atmospheric dispersion modeling of gaseous releases, such as might occur during an emergency at a chemical plant or more routinely from a stack. This is intended to be the level of disperson modeling used support consequence analysis or QRA such as is described in Lee's Loss Prevention in the Process Industries or the CCPS Guidelines for Consequence Analysis of Chemical Releases.

Installation

GasDispersion.jl can be installed using Julia's built-in package manager. In a Julia session, enter the package manager mode by hitting ], then run the command

pkg> add GasDispersion

Example usage

Suppose we wish to model the dispersion of gaseous propane from a leak from a storage tank, where the leak is from a 10mm hole that is 3.5m above the ground and the propane is at 25°C and 4barg. Assume the discharge coefficient $c_{D} = 0.85$. This scenario is adapted from CCPS Guidelines for Consequence Analysis of Chemical Releases

First we define the scenario

using GasDispersion

propane = Substance(name="propane",
              molar_weight=0.044096,     # kg/mol
              liquid_density=526.13,     # kg/m³
              k=1.142,
              boiling_temp=231.02,       # K
              latent_heat=425740,        # J/kg
              gas_heat_capacity=1678,    # J/kg/K
              liquid_heat_capacity=2520) # J/kg/K

Patm = 101325 # Pa
P1 = 4e5 + Patm # Pa
T1 = 25 + 273.15 # K

scn = scenario_builder(propane, JetSource; 
       phase = :gas,
       diameter = 0.01,  # m
       dischargecoef = 0.85,
       temperature = T1, # K
       pressure = P1,    # Pa
       height = 3.5)     # m, height of hole above the ground

This generates a Scenario defined for a gas jet discharging into dry air at standard conditions.

An alternative to supplying all of the substance properties, which can get rather onerous, is to use the library of substances and equations of state provided in Clapeyron.jl

using GasDispersion, Clapeyron

propane = Substance(PropaneRef()) # uses an empirical EoS for propane

propane = Substance(PR("propane"; idealmodel=ReidIdeal)) # uses the Peng-Robinson EoS

Once we have this defined we can determine the concentration at any point downwind of the release point, assuming the release is a continuous plume, using

p = plume(scn, GaussianPlume)

Where p is a callable which returns the concentration (in vol fraction) at any point. For example at 100m downwind and at a height of 2m

p(100,0,2)

# output

0.0002006455298894473

See the documentation for details on the additional plume and puff models and worked examples.