
Location-Specific 3D Terrain Modeling
An analysis will be made of the facility’s surrounding terrain. This type of terrain profiling is important from a wind acceleration and turbulence points of view.
The Meshed Analysis Area and its Content
Once the terrain is modeled in 3D, the analysis area (computational domain) is outlined and then Meshed. The mesh which can have many sections and segments, may also have many different densities (usually higher density where there is a greater level of fluid movement or where because of presence of an entity of interest (e.g. an ignition source) a greater level of computational focus is needed.
The placement of the meshed 3D facility model inside the 3D terrain model ensures that background air movements (wind acceleration) and convective bounce-back of the hot plumes is all very accurate.


Ignition and Combustion Modeling of of Flammable Plumes
In absence of an ignition source, a flammable plumes will just pass through a location and subsequently take an upwards (under the influence of differential buoyancy) path.
Ignition and Combustion of Flammable Plumes
In presence of an ignition source (of sufficient strength), the flammable portion of plume will ignite. The flame subsequently spreads throughout the plume. Its rate and extent of spread however will be determined by concentration profile of the gas (where it is flammable and where it is not). The following time lapsed screen shots demonstrate this.



A well-constructed CFD model will take account of all of these factors. So, the results are often logical and reliable.
In presence of a heating source (flame), the plant’s various material begin heating up at different rates (and this depends on many factors including flame shape and view factor (which are constantly changing), material heat capacity and emissivity, location, hiding/shielding etc.
Facility Material of Construction Survey
A survey of facility’s material of construction is a very important aspect of the combustion / heating component of these studies. Material is often specified by type e.g. concrete, wood, sheet metal, load bearing structural elements (steel), Carbon Steel, Stainless Steel, etc.
The incident radiation, hot plumes (convection) and the conduction components are all very sensitive to the type and mass of target material.
The final results will be heavily influenced by not only the intensity and duration of the heating but also by the receptor areas absorption characteristics.
Depending on the material of construction, mass, proximity to flame front, and heating duration different material can experience different rates of temperature rise. So accurate material specification is a very important issue.


