• Kirstine Meyer Frandsen
  • Malthe Haahr Hvelplund
The purpose of this project is to gain a deeper understanding of particle exposure in an anatomically correct model of the lower airways. The model has been developed from the CT-scanning of a human male. This is a new approach to investigating the effect of indoor airborne particles on the human occupants. The CT-scanning is applied to develop a 3D printed model for experimental use and the same geometry was used to conduct CFD simulations in a numerical investigation. The experimental investigation focused on four different types of cooking oil, which generate real polydispersed particles. The 3D printed airway model was placed in close proximity to the emission source and particle concentration was measured in several locations in the displacement ventilated clean room. The duration of the measurement extended from the start of the source-active period until initial conditions were reached. The investigation concluded that the mass concentration varies with a factor of five between peak concentrations of the different oil types. Olive oil generated the most particles and sunflower oil generated the least. The size-resolved distribution of the cooking emitted particles were based on number concentration and showed to be very similar for the different oil types, as well as during the different times of the measurement. Thereby the difference in mass concentration was not due to the sizes of the particles but more likely the smoke points of the various oils. Peak concentration was almost reached simultaneously for the different measurement locations. The effect of the thermal plume on mass concentration in the breathing zone was also investigated by a thermal manikin. This showed no differences in mass concentration due to an overpowering thermal plume generated by the emission source. The numerical investigation was used to analyse the regional particle deposition of monodispersed particles. Steady state CFD simulations were carried out due to time constraints set by the computational power. Results showed that the majority of the particles were deposited in the bronchi. Accumulation particles (0.1 - 2.0 microns) have the smallest deposition fraction in the lower airways. An increase in the aerodynamic diameter (>2.0 microns) of the particles elevated the deposition fraction. A comparison of the deposition fractions from the experimental and numerical investigations showed a big deviation. This is attributed to the different parameters set and assumptions applied in the process. Overall this study advances knowledge on the characteristics of both exposure and intake of particles by the implementation of state-of-the-art technology. This knowledge contributes to future investigations into control methods that minimise the negative health impact of indoor emissions.
Publication date8 Jun 2018
Number of pages175
ID: 280606266