A novel reusable anti-COVID-19 transparent face respirator with optimized airflow

Abstract

This novel face mask is designed to be a reusable respirator with a small and highly efficient disposable fabric filter. Respirator material requirements are reduced by 75% compared to traditional designs and allow repeated cleaning or sterilization. The probability of virus particle inhalation is reduced using novel air filtration pathways, through square-waveform design to increase filter airflow. Air enters the mask from right and left side filters, while the area in front of the mouth is isolated. Clear epoxy is used for a transparent frame, allowing lip-reading, and mask edges contain a silicone seal preventing bypass of the filters. The mask is manufactured using silicone molds, eliminating electricity requirements making it economical and viable in developing countries. Computational fluid dynamics numerical studies and Fluent ANSYS software were used to simulate airflow through the filter to optimize filter air path geometry and validate mask design with realistic human requirements. The breathing cycle was represented as a transient function, and N95 filter specifications were selected as a porous medium. The novel design achieved 1.2 × 10^-3 kg s^-1, 20% higher than human requirements, with air streamlines velocity indicating local high speed, forcing and trapping virus particles against filter walls through centrifugal forces.

Keywords: COVID-19; Flow; Mask; Pressure; Prototype; Temperature.

Fig. 1

Process flowchart for the initial design and product development procedure using CAD, flow simulation, 3D printing, and cold molding processes

Fig. 2

Photograph extracted from SolidWorks. a front, b side view of the final mask design, c disassembled mask parts, and d sectional front view of the filter area of the mask

Fig. 3

Three-dimensional model domains of this mask study

Fig. 4

Mesh generation for a the full domain, b the inner domain, and c the filter domain

Fig. 5

The relationship between a volumetric flow and time and b pressure and time for the normal, middle, and deep breathing conditions

Fig. 6

Velocity distribution for the top section of the mask at times a = 0, b = 0.4 s, c = 1.0 s, d = 2.6 s, e = 3.8, and f = 5.0 s

Fig. 7

Velocity streamlines during normal breathing at the inner and filter domains of the mask at 1 s, where (a), (b), (c) are different views of the mask and (d) demonstrates the airflow streamlines of the inner domain of the filter

Fig. 8

(a) Pressure distribution streamlines for filter domain. (b) Temperature distribution at cross top section of the full domain for (i) t = 0 s, (ii) t = 0.4 s, (iii) t = 1.0 s, (iv) t = 2.6 s, (v) t = 3.8, and (vi) t = 5.0 s