Transport of fine particles in a standardized human nasal cavity

Understanding particle transport through human nasal cavities is a critical step towards accurate prediction of deposition of inhaled hazardous particulates or medicinal sprays. Magnetic Resonance Imaging (MRI) was used to obtain 3D, 3-component velocity and 3D particle concentration data in a model of the Carleton-Civic Standardized Nasal Cavity, which provides a balance between generality and patient-specific features. The 3D mean velocity field was obtained for clean flow at two anatomically relevant Reynolds numbers. The velocity data show that the flow is likely transitional, weakly dependent on flow rate, and contains important secondary flow features resulting from the convoluted nasal passage geometry. A newly developed MRI diagnostic for 3D particle concentration was used to obtain the mean volume fraction field for two particle-laden streaks injected just upstream of the nostril. The full-field concentration data can be used to quantify the mixing between the two streaks, which shows that the fastest mixing occurs in the nasal vestibule (nostril). However, certain portions of the upper nose (e.g., the olfactory region) are only reached by particles injected near the nostril tip, which could have useful implications in the medical arena.