Session: 10.2.2 - Interfacial Phenomena and Flows II

Paper Number: 158593

158593 - Experimental and Numerical Studies of Mask Misfit on Thermoregulation and Moisture Retention With Facemask Wearing 

Abstract: 

Wearing masks can cause discomfort, which may unconsciously lead individuals to loosen them, potentially reducing their protective effectiveness. This study explored how leakage impacts mask-related heat regulation and moisture trapping to guide improved mask design. A computational model was developed to capture the complex interactions among the environment, mask, face, and airway under a range of mask-fitting imperfections, accounting for fluid flow, heat transfer, and moisture dynamics. The physics considered includes transient temperature variations, thermal buoyancy effects, tissue heat generation, vapor phase transitions, and fluid/heat/mass transfer through porous materials.  The computational model was validated through multiple techniques: Schlieren imaging, thermal imaging analysis, and velocity/temperature measurements.

The results of this study demonstrate an inverse relationship between mask leakage and the temperature and humidity on the facial skin under the mask. Experimental and simulation results indicated that buoyancy-driven flows and exhalation momentum produced similar influences, highlighting a sensitive equilibrium between naturally induced and forced convection. The leakage fraction does not remain uniform throughout a breathing cycle, but instead steadily increases during the exhalation phase. When the mask was fully sealed, the nose region persistently exhibited elevated temperatures, whereas introducing small gaps allowed cooler air to enter during inhalation and reduce these temperatures. Vapor condensation was observed within the mask material during exhalation across all mask-wearing scenarios.

Presenting Author: Kian Barari University of Massachusetts Lowell

Presenting Author Biography: Kian Barari is a PhD Candidate in Biomedical Engineering at UMass-Lowell.