Artículo de revista
OpenFOAM applied to the CFD simulation of turbulent buoyant atmospheric flows and pollutant dispersion inside large open pit mines under intense insolation
Fecha
2014Registro en:
Computers & Fluids 90 (2014) 72–87
dx.doi.org/10.1016/j.compfluid.2013.11.012
Autor
Flores Meneses, Federico Esteban
Garreaud Salazar, René
Muñoz Magnino, Ricardo
Institución
Resumen
The particular conditions of air circulation inside large open pit mines under intense insolation, dominated
by mechanical and buoyant effects, are crucial when studying the dispersion of pollutants inside
and outside the pit. Considering this, we study this problem using CFD tools able to include the complex
geometry characterizing it and the different processes affecting circulation: flow interaction with obstacles,
buoyancy, stratification and turbulence. We performed simulations using a previously developed
OpenFOAM solver, focusing in the particular case of Chuquicamata, a large open pit mine ( 1 km deep)
located in northern Chile. Both idealized and real topographies were used. Given the importance of turbulence
in this type of large-scale flows we have used LES to incorporate it in the calculation, using a DES
approach to solve the flow near walls.
The results from the idealized cases support the idea that buoyant currents foster the exit of particles
from the pit and increase the turbulence inside its atmosphere, modifying the purely mechanical recirculatory
flow inside the cavity. Differences in the air circulation and dispersion of particles between idealized
and non-idealized cases are reported. In particular, there are changes in the intensity and location
of the recirculation inside the pit due to variations in the aspect ratio (length/depth) of the cavity along
the axis perpendicular to the main flow. Also, the topography surrounding the mine affects the main flow
that sweeps the cavity, channeling it along the main axis of the pit and forcing it to enter the cavity
through the lower level of the top edge. As a consequence, the patterns of pollutant transport observed
in the idealized cases, dominated by near-wall upward currents, are different than those observed in the
cases with complex topography, where the dispersion is dominated by internal buoyant upward currents.
Anyhow, whether by internal or near wall upward currents, in all buoyant cases considered a large percentage
of the particles injected inside the pit leaves the cavity.
Further experiments studying the effect of 3D aspect ratio over the mechanically forced internal flow
are needed to fully understand the effect of the internal geometry of the pit over the flow.