Deposition and resuspension of nuclear aerosol particles in turbulent flows
The transport, deposition and resuspension behaviour of carbonaceous dust in the primary circuit of a High Temperature Reactors (HTR) is a fundamental safety issue for the development and safety assessment of such a reactor. Thus, experimental studies are performed within two large-scale European projects (ARCHER, THINS) to explore the deposition and resuspension characteristics of aerosol particles in turbulent flows. Two different test facilities were designed to systematically investigate single effects influencing the particle transport behaviour.
Fig.1: Schematic drawing of the Gas Particle Loop and instrumentation.
The Gas Particle Loop (Fig. 1) is used to study the particle deposition and resuspension in a well-defined horizontal square duct flow. The turbulent flow field was measured by means of Particle Image Velocimetry (Barth, et al., 2011). Wall deposited particles were counted and classified using optical and scanning electron microscopy (Barth, Lécrivain, et al. (2013), Barth, Preuß, et al. (2013)). Furthermore, multilayer particle deposition and resuspension between periodic steps was studied to explore the interaction between the turbulent flow and the particles (Barth, Reiche, et al., 2013).
Fig.2: Schematic drawing of the Pebble Bed Loop and positron emission tomography measurement principle.
The Pebble Bed Loop (Fig. 2) was designed to investigate the particle transport characteristics in a model pebble bed. The aerosol particles were radioactively labeled before being dispersed into the flow and the formation of the particle deposits during various flow regimes was recorded using positron emission tomography (Barth et al., 2013b).
The experimental investigations are supported by CFD (computational fluid dynamics) code development. Thus, a two-layer model was implemented in a CFD code to account for the anisotropy of the turbulent flow and the experimentally measured deposition rates were correctly predicted (Lecrivain & Hampel, 2012). Furthermore, the particle multilayer build-up between the periodic steps was accurately captured by means of an adaptive mesh generation basing on comptutational granular mechanics and CFD (Lecrivan et al., 2013). The existing data sets provide a deeper insight to the complex transport phenomena of aerosol particles in turbulent flows and can be used for CFD code development for the simulation and safety assessment of HTRs.
Barth, T., Banowski, M., & Hampel, U. (2011).
PIV measurements on the formation of the flow field and aerosol particle distribution in a turbulent square duct flow (Vol. 9).
WIT Press, Southampton, Boston.
- Barth, T., Lécrivain, G., & Hampel, U. (2013).
Particle deposition study in a horizontal turbulent duct flow using optical microscopy and particle size spectrometry.
Journal of Aerosol Science.
- Barth, T., Ludwig, M., Kulenkampff, J., Gründig, M., Franke, K., Lippmann-Pipke, J., & Hampel, U. (2013b).
Positron emission tomography in pebble beds, part 1: liquid particle deposition.
Nuclear Engineering and Design.
- Barth, T., Preuß, J., & Hampel, U. (2013).
Single particle resuspension experiments in turbulent channel flows.
In 8th International Conference on Multiphase Flow, Jeju, Korea.
- Barth, T., Reiche, M., & Hampel, U. (2013).
Experimental investigation of multilayer particle deposition and resuspension between periodic steps in turbulent flows.
Journal of Aerosol Science, accepted for publication.
- Lecrivain, G. & Hampel, U. (2012).
Influence of the Lagrangian Integral Time Scale Estimation in the Near Wall Region on Particle Deposition.
J. Fluids Eng. 134(7),
- Lecrivain, G., Drapeau-Martin, S., Barth, T. & Hampel, U. (2013).
Numerical simulation of multilayer deposition in an obstructed channel flow.
Advanced Powder Technology.
EC, Project THINS, grant agreement no. 249337, Feb. 2010 – Feb. 2014.
EC, Project ARCHER, grant agreement no. 269892, Feb. 2011 – Feb. 2015.
TUD, NRG, KIT, ICL