Wet surface wall model for latent heat exchange during evaporation

Abstract

Air conditioning is a dual heat and mass transfer process, and the human nasal cavity achieves this through the mucosal wall surface, which is supplied with an energy source through the sub-epithelial network of capillaries. Computational studies of air conditioning in the nasal cavity have included temperature and humidity, but most studies solved these flow parameters separately, and in some cases, a constant mucosal surface temperature was used. Recent developments demonstrated that both heat and mass transfer need to be modeled. This work expands on existing modeling efforts in accounting for the nasal cavity's dual heat and mass transfer process by introducing a new subwall model, given in the Supplementary Materials. The model was applied to a pipe geometry, and a human nasal cavity was recreated from CT-scans, and six inhalation conditions were studied. The results showed that when the energy transfer from the latent heat of evaporation is included, there is a cooling effect on the mucosal surface temperature.

Impacts of Mask Wearing and Leakages on Cyclic Respiratory Flows and Facial Thermoregulation

“…Salati et al [30] reported that N95 respirator mask breathing leads to excessive carbon dioxide inhalation and reduced heat transfer in the human nose. Inthavong et al [31] also showed a cooling effect on nasal mucosa from the latent heat of evaporation. Facial temperature and discomfort in healthcare workers were studied by Lembo et al [32], Zhu et al [33,34], and Beonell et al [35]; all reported a significant increase in facial temperature, but the increasing magnitude varied with the mask type, length of wearing time, and the individual's physical activity.…”

Effects of decongestion on nasal cavity air conditioning efficiency: a CFD cohort study

“…Such as Lindemann et al and Pless et al, did not incorporate water vapor transport. 8, 9 Garcia et al investigated the nasal cavity heat and water vapor transport between control and pathological subjects by assuming both constant cavity surface temperature and relative humidity. 7 A two-lm theory was applied in simulating the heating of nasal cavity air by Kumahata et evaluated the effects of latent heat, while the water transfer model assumed fully saturated conditions at the wall of the nasal cavity.…”

“…8 More recently, a study by Inthavong et al applied a two-lm theory to both the heat and water model in simulating the nasal cavity air-conditioning over a limited number of subjects. 9 The nasal cycle, a natural physiological process, alternately decongests one side of the nasal cavity approximately every two hours, leading to anatomical variations that can affect air-conditioning e ciency. 10 Prior studies often utilized single geometric models per subject, based on the nasal anatomy at the time of imaging, although it has been shown considering the airway dynamics can make big difference in CFD predicted resutls.…”

“…10 Prior studies often utilized single geometric models per subject, based on the nasal anatomy at the time of imaging, although it has been shown considering the airway dynamics can make big difference in CFD predicted resutls. 9,[11][12][13][14][15][16][17][18][19] In this study, we aim to quantify the in uence of anatomical variation on the e ciency of nasal air conditioning. By applying a nasal decongestant to both sides of the nasal cavity, we mimicked not only an extreme state of the nasal cycle using decongestant, representing the most decongested state possible, but also the use of decongestants is relevant for their practical application in temporarily alleviating nasal obstruction.…”