Abstract:
This study particularly aims at understanding flow and pollutant dispersion when flat
terrain, single hill and hill with obstacles are present. The emissions of ethylene from
a point source are located in eight different positions. For the hill cases, the sources
are located downwind from the top of the hill, and the data are collected at various
locations.
The commercial software packages Gambit 2.4.6, Fluent 6.3.26 and Tecplot 360 are
used for the two-dimensional mesh generation, for the flow simulation and for the
validation respectively. The numerical results are compared with experimental and
numerical data for the single hill case and for the point source using the Spalart-
Allmaras model, k-ε Standard, k-ε RNG and k-ε Realizable models. The comparison
of the results shows that the k-ᵋ Standard model is in good agreement with the
experimental and numerical data.
Results also show that the mass fraction of ethylene is highest for the flat terrain case.
The next highest mass fraction of ethylene is found for the case with the hill and
obstacles, and the single-hill case has the lowest. Moreover, upwind of the first
obstacle the average mass fraction is larger than inside the first and the second
canyons, and the minimum pollutant is downwind of the last obstacle. The average
mass fraction of ethylene is measured at the corners of the canyons, and the results
show that generally the bottom left corners have a higher mass fraction than the
middle and bottom right side.