Project Summary
Our understanding of pathogen laden droplet/particle cloud formation and propagation remains
limited. Several approaches including use of computational tools, experimental tests by tracking
ejected droplets from subjects during emissions, and limited simulators by pumping and
dispersing powders, have been implemented. Yet there is no adequate respiratory emission
emulator that could holistically replicate saliva liquid atomization and the breakup process
corresponding to each main explosive event such as sneezing, coughing, or speaking loudly. In
this proposal, our overarching aim is to fill this gap by developing and testing a spray system
that emulates respiratory events. This device can be used as an alternative subject to mimic the
main respiratory events with higher flexibilities in terms of availability/safety, superior droplet
tracking, and wider representation of subjects. To develop this new device, three specific aims
are proposed: Aim 1. Design and fabricate the emulator spray system capable of simulating
respiratory events in terms of droplet size & velocity distributions and counts of the formed
droplet cloud. The system includes a hardware and a PC-based control unit to enforce desired
air pressure profile, particular to each type of emission and ensued droplet cluster. Aim 2.
Characterize emulator ensued plume and compare it to ejected droplet cloud from actual
respiratory emissions using high-speed imaging and laser diffraction. Aim 3. Find relevant
pulsating pressure and flowrate profiles to emulate typical explosive respiratory events. The
long-term goal of the project is to add more features to the device (e.g. adding motions) to
gradually approach the actual phenomena.
This novel proposed emulator can be used to mimic flow and evolution of pathogen laden
droplets; therefore, it provides opportunities for training healthcare workers and the public on the
best preventative practices and design of adequate ventilation systems. Furthermore, the project
aids faculty and underrepresented students at Tuskegee University (a Historically Black
University) in developing/testing a novel mechanical emulator to better understand a virus
propagation route through engineering tools. It also helps students to see how engineering and
other disciplines can come together and contribute to a public health crisis.
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