Gas composition and volume

The Gas composition and volume tab allows the user to define the position, size, concentration and composition of a gas cloud.

The volume fractions editor and the materials database can be accessed by clicking Edit volume fractions. The editor and available species list is shown in the image below.

The SLAM Data column indicates whether the database contains the burning velocity data required to simulate an explosion for that species.

The Properties column indicates whether a species is flammable or toxic.

Species can be added to the Used Species column by double-clicking the species or by selecting and pressing the > button.

Species can be removed from the Used Species column by selecting the species and pressing the < button.

The volume fraction of each species is entered and FLACS-CFD will normalise the values i.e., fractions do not need to add up to 1.  

Equivalence ratios

• ER0 - equivalence ratio inside the gas cloud, typically around 1 for explosion scenarios and a very high number for dispersion scenarios, i.e., 1E+30.

• ER9 - equivalence ratio outside the gas cloud, typically 0.