Figure 3.

Subsystems of the model: air enters with ambient temperature $T_{\text{amb}}$ and relative humidity ${\phi }_{\text{amb}}$. The nasal cavity with air is denoted (a), the liquid mucus layer (m), the interstitial tissue (it), vein (ven), and artery (art). Red and blue arrows indicate the heat and water fluxes, respectively, while black arrows indicate the flow of air and blood. All fluxes are in the r-direction and flows are in the z-direction. For a definition of fluxes, see text. To see this figure in color, go online.