ESEL Paper Review_20120901
By Hong Guo
1, Title and Author
Title: CFD model simulation of dispersion from chlorine railcar release in industrial and urban areas
Journal: Atmospheric Environment
Authors:
Steven R.Hanna a,*, Olav R.Hansen b, Mathieu Ichard b, David Strimaitis c
a Hana Consultants, 7 Crescent Ave., Kennebunkport, ME 04046, USA
b GexCon, Bergen, Norway
c TRC, Lowell, MA, USA
2. Summary of Paper
In this paper, the FLACs -Computational Fluid Dynamics (CFD) model was used to simulate the transport and dispersion Comparisons are made between simulations of concentrations by the FlACS model and those of some of the standard widely used dense gas models.
Here, we could found that the use of CFD models such as FLACS to calculate dispersion is widespread in explosion quantitative risk assessment, and is recommended by industry standards in certain countries.
3 Results
The two scenarios are designed to simulate in this paper as follows: 1, Festus, Missouri, accident involving a chlorine railcar 2, A hypothetical railcar release in a built-up urban area in Chicago. The obstacles (buildings, road, districts) and wind speed, and concentration of toxic pollutant will be included into the model for simulating the above two scenarios. Due to no concentration observation, it is not possible to carry out quantitative evaluations of the FLASCS concentration predictions.
3.1 Festus
The FLACs simulated 2000ppm cloud compares well in a qualitative manner to the observed chlorine cloud. And in the FLACS simulations where a constant source emission rate is assumed, the visible gas cloud is simulated to reach a steady state in the domain around the 10 min after the release starts.
3.2 Chicago set up and results
Scenario 1 (south wind) shows that the chlorine gas is transported much faster and with less dilution through the area with flat open terrain , extending more than 1000m downwind d of the source location, than it is after it encounters the area with buildings.
Scenario 2 shows that there are building s closer to the source than in scenario 1, but the 100 ppm contour extends about 45 % farther, to about 3200m. The cloud in scenario 2 encounters less turbulence and hence less dilution due to the fact that the buildings are smaller along the trajectory of the chlorine cloud
3.3 Comparison
It is concluded that the FLACS CFD model prediction s of plume centerline concentrations are not inconsistent with the predictions of the widely-used simple dense gas models. The advantage of FLACS and other CFD models is their ability to simulate the local effects of buildings wake, slight terrain differences, and possible mitigation measures like fence
4. Contribution:
The purpose of this study has been to determine if a CFD model (FLACS) would provide realistic ?appearing simulations of the dense cloud resulting from a large chlorine release from a railcar in an area. The FLACs (CFD model) are introduced in the area of the atmospheric field. Now I just study the CFD study, and this paper give me the insight to the atmospheric area. Moreover, I will study the different CFD model to the variety of research area.
4. Author information:
Email: hannaconsult@roadrunner.com (S.R Hanna)