#AAAR2022 Suppressing Spread of Viral Sneeze Droplets Using Transparent Curtains in Large Food Processing Facilities. SUNIL KUMAR, Maria King, David Klassen, Texas A&M University
Modeling rooms with and without partitions
Many studies show HVAC matters (a lot) in reducing spread of virus.
Meat plants have been reported as hot spots throughout the world.
Why? What's the deal with the meat plants? What makes them unique (and terrible) for spreading this disease.
Low temps.
High aerosol concentrations in the air (due to meat processing operation)
Low temps.
High aerosol concentrations in the air (due to meat processing operation)
Mitigation methods
- Partitions.
- Some masks.
- Still need more measures to protect these workers
- Partitions.
- Some masks.
- Still need more measures to protect these workers
Current approach pictures - Fabrication room. Evaporator in the room is major HVAC component. Several tables. Central conveyor belt. Workers on both sides of that.
- No plastic dividers between workers.
- Some plastic divider between worker.
- No plastic dividers between workers.
- Some plastic divider between worker.
We used CFD methods to model spread of the virus. So they built a solidworks model of the fabrication build. 32x32x10m. Roof exhaust. Extra exhaust ports on the walls. Experimental measures of positive pressure flow into the room.
Model humans. Workers are always dressed in PPE (in reality and in the model)
Modeled a roof&vertical plexiglass barrier.
Set their CFD with all these inputs... lots of numbers.
Set their CFD with all these inputs... lots of numbers.
Droplet velocities and deposition assumptions in the model. This equation was based on experimental basis from the existing literature.
For the CFD model - evaporating droplet diameter and free-fall height were validated with experimental data in lit.
For the CFD model - evaporating droplet diameter and free-fall height were validated with experimental data in lit.
In essence. Sneeze. Droplet exits. Droplet evaporates. Droplet shrinks. Droplet floats around the room.
They model a turn-around (backwards sneeze). And then the CFD model does all this work describing where the sneeze droplet goes.
They model a turn-around (backwards sneeze). And then the CFD model does all this work describing where the sneeze droplet goes.
8 columns of workers. Higher numbers of air-streamlines in the workers breathing zones = higher risk of disease spread. Virus is entrained in the air. Spread in the air. So key is avoiding those air streamlines.
Without partitions we count the number of streamlines reaching workers is 77 streamlines. There are some vertices that keep the contaminants floating in the air for a long time.
With the partitions, 19 streamlines hit workers. These reduced risk of transmission.
With the partitions, 19 streamlines hit workers. These reduced risk of transmission.
Conclusions:
- From this study the HVAC system plays a critical role.
- Partitions were very helpful in reducing streamlines by ~90% compared to no partitions
- You can read all about it in their publication.
Email: ksunil@tamu.edu
- From this study the HVAC system plays a critical role.
- Partitions were very helpful in reducing streamlines by ~90% compared to no partitions
- You can read all about it in their publication.
Email: ksunil@tamu.edu
Q&A: Within the partition what is the fate of exhaled droplets?
Yea. With partitions... I am not sure. Need to follow-up with you later.
Yea. With partitions... I am not sure. Need to follow-up with you later.
Q&A: Do you know whether they stimulated laminar or turbulent flow?
Ans: Turbulent.
Ans: Turbulent.
Q&A: What was the emitted droplet size and number concentration in the sneeze?
Ans. Ask ksunil@tamu.edu
Ans. Ask ksunil@tamu.edu
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