Reference experiment on aerosol particle transport for dynamic situations

To study airborne transport of aerosol particles by mixed convection and dynamic situations within a closed room, the Cottbus Aerosol Particle Reference Experiment (CARE) was built and equipped, which includes thermal manikins and a spreader dummy. For various flow configurations (location of spreader, heating bodies, windows opened, air ventilation with and without air purification systems) flow visualisation was performed, particulate matter sensors (PMS) measured local particle concentrations, head-mounted camera systems counted particle concentrations of individuals and finally, large field of view Shake-The-Box Particle Tracking delivered velocity fields. The comprehensive experimental configuration of different measurement systems are discussed in terms of their aerosol transport properties and quantitative results, effective application and comparative efficiency explaining the flow dynamics. The findings from these experiments also provide information under which circumstances particularly high concentrations of aerosol particles can be found on which locations

Referenzexperiment zum Aerosolpartikel-Transport für dynamische Situationen

Airborne transport of aerosol particles is the main path of SARS-CoV-2, measles or other respiratory virus infections in closed rooms. Infection risks must be determined through parametric dispersion studies, which can be done by simulations and experiments. The most approaches to study the aerosol transport are in static situations, however, in real world, most situations are rather dynamic with e.g. people walking around, which is expected to have an impact on the aerosol distribution in the room. We are aiming at studying real-life dynamic situations involving several moving persons with head mounted camera systems and evaluate the amount of potentially inhaled aerosol particles at the individuals. To study these, a reference room was established at BTU Cottbus-Sfb, where beside the dynamic situations also static cases are analysed using seated thermal manikins, inducing turbulent thermal plumes and mixed convection flows inside the test room. We use several measurement techniques to reveal the flow fields and especially the aerosol transport and traces. Fast mobility particle sizer (FMPS3091 by TSI Coorp.) measure locally detailed particle size distributions, while calibrated low-cost particulate matter sensors can be adapted in huge number inside the room allowing a space and time resolution of the local concentrations in the diameter range from 0.3-2.5 µm. A mobile measurement system (MMS) developed at DLR controls and reads out the Sensirion SPS30 sensors [DOI: 10.5281/zenodo.6471388]. Flow visualisation is performed for brief analysis of various flow configurations (location of spreader, heating bodies, windows opened, air purification systems used). Finally, attention is given to some cases, which are studied in further detail by the use of large field of view Shake-the-Box Particle Tracking, which employs HFSB as tracers and pulsed LED-arrays for illumination. STB will deliver long time-series of several m² sized Lagrangian and Eulerian velocity fields. We here discuss the experimental configuration of simultaneous Particle counting, tracing and velocity measurements inside the Cottbus aerosol particle reference experiment