Integrating dispersion modelling and experimental approach to optimize indoor/outdoor detection of airborne agents. Mimicking the exposure of an infrastructure - JRC Technical report
Cardarilli, M. (editor)
The overarching objective of the ERNCIP “Detection of Indoor Airborne Chemical & Biological Agents” Thematic Group (TG) is to strengthen resilience of critical infrastructure against airborne CB threats by improvement of detection capabilities. The subsidiary aim of the research described in this technical report is to develop knowledge on the behaviour of chemical releases, given some likely attack scenarios, and to propose ways to optimally detect those inside buildings. Making use of a combined approach consisting of experiments and dispersion modelling is considered a strong endeavour towards this aim. To provide input for dispersion model development a series of medium-scale experiments with representative simulant chemical has been designed. The study made use of controlled release of simulant chemicals in an ambient breeze tunnel (AMB). In the AMB a mock-up of a simple building was installed (scale 1:5). The experiments involved three mimicked attack scenarios: i) focal release from within the mimicked building and external release of agent approaching the mock-up from the outside from a ii) short and iii)a larger distance. Tri-ethylphosphate (TEP) was selected as simulant (for nervegases). The detector used was an ion mobility spectrometry (IMS) instrument. Release of TEP was successful in all three exposure scenarios, it resulted in reproducible detection signals from 6 IMS instrument placed in 6 rooms of the building mock-up. The speed and magnitude in which TEP levels were recorded in the respective rooms showed a clear and reproducible picture in the sense that some of the rooms appeared to be better reachable for the externally released TEP than others. Subsequent 2 different dispersion modelling approaches were undertaken to understand and describe those differences: I.the Code_Saturne1 has been used to perform the simulations both before and afterthe experiments. Pre-trials computations illustrate the differences in the dispersionpattern when an internal versus an external released is considered. Post-trialscomputations are fully consistent with the pre-trials computations and the physicalphenomena enlightened in the different trials; II. The ADREA-HF code2 has been used to perform the simulations utilizing the CFDRANS approximation and the standard k-ε turbulence model. The results show thatrooms concentrations time profiles can be quite different. The room specific locationwith respect to the source and the associated ambient air pattern plays an importantrole to this differentiation. The poorly ventilated rooms are associated with relativelylong residence and arrival times. The poorly ventilated rooms tend to lower the peakconcentrations.
To reference this document use:
Military chemical agents
EUR 31172 EN JRC 129051
Publications Office of the European Union, Luxembourg
This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 775989, as part of the European Reference Network for Critical Infrastructure Protection project.