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Thesis Defence: Capture and Thermal Inactivation of Airborne Pathogens by Multi-Layer Wire Mesh Screens
August 4, 2023 at 1:30 pm - 4:30 pm
Reza Zarghanishiraz, supervised by Dr. Sunny Ri Li, will defend their thesis titled “Capture and Thermal Inactivation of Airborne Pathogens by Multi-Layer Wire Mesh Screens” in partial fulfillment of the requirements for the degree of Master of Applied Science in Mechanical Engineering.
An abstract for Reza Zarghanishiraz’s thesis is included below.
Defences are open to all members of the campus community as well as the general public. Registration is not required for in person defences.
ABSTRACT
The critical lessons learned from the Covid-19 pandemic underscore the utmost importance of
proactively addressing airborne transmitting diseases, necessitating comprehensive research and
development of air purifying devices aimed at eliminating airborne pathogens, to safeguard public
health. In this study, particle-laden airflow is passed through multiple layers of finely woven
nichrome mesh screens located at different angular orientations which will both capture the
particles and inactivate the pathogens by thermal treatment. The nichrome mesh screens are used
as heating elements by applying a voltage to them to heat the air and take it to 150°C. It has been
shown in the previous studies that the required exposure time for achieving a 3-log reduction of
viral load (i.e. 99.9% inactivation) in SARS-CoV2 as a pathogen example at this temperature is as
small as 0.02 s. The proposed novel device can either be utilized as a portable air purifier or be
combined with the HVAC system of a building as a complementary component to provide clean
pathogen-free air for indoor spaces. More than 47 core-year computational resources were
employed for Computational Fluid Dynamics (CFD) simulations in an Eulerian-Lagrangian
framework using ANSYS Fluent to study the particle removal efficiency of the mesh screen layer
in 16 airflow velocities ranging from 0.01 − 5 m/s for 10 particle size groups ranging from
50 nm − 10μm. The impact of multiple geometrical and flow properties on the removal efficiency
was studied such as wire diameter, mesh porosity, layer distance, orientation of the layers,
turbulence, and heating and airflow temperature. The results were presented based on
dimensionless parameters, Stokes and Peclet numbers and were compared to the previous studies.
