One of the most challenging aspects of coronavirus disease 2019 (COVID-19) is that a newly infected individual shows diagnosable symptoms, such as body temperature rise, several days after contracting the disease. In the early phase of infection (i.e., incubation period), an undiagnosed and unaware individual can spread the virus to others. The fastest and most efficient route of COVID-19 transmission is the respiratory system. Therefore, developing a model of the respiratory system to predict

1. Simulation of Lungs for the
Respiration Process using DWSIM
Presenting by
Bharath M Ch
Department of Chemical Engineering
Rajiv Gandhi University of Knowledge
Technologies.

2. Background
● One of the most challenging aspects of coronavirus
disease 2019 (COVID-19) is that a newly infected
individual shows diagnosable symptoms, such as body
temperature rise, several days after contracting the
disease.
● In the early phase of infection (i.e., incubation period), an
undiagnosed and unaware individual can spread the virus
to others.
● The fastest and most efficient route of COVID-19
transmission is the respiratory system. Therefore,
developing a model of the respiratory system to predict
changes in the lung performance upon COVID-19
infection is useful for early diagnosis and intervention
during the incubation period.

3. ● The mass balance was performed on the lungs to relate
any sudden changes in the O2 or CO2 composition of the
exhaled gas to the O2 consumption rate, which is an
early indicator of lung dysfunction due to infection.
● The inhaled air at ambient temperature, pressure, and
Relative Humidity was warmed and saturated with
moisture from the lung tissue, along with O2 and CO2
exchanges from food consumption in the stomach and
intestines.
Mass Balance
A schematic representation of major material streams crossing
the lung boundaries.

4. The exchange of O2, CO2, and H2O in our lungs saturates the air with moisture from the lung tissue
at Body Temperature.

5. Assumptions
● The body temperature was set constant at 37°C.
● The role of background factors affecting the body function, such as
personal health status, diet, and environmental conditions, must be
distinguished from the symptoms of a viral infection.
● Finally, the effects of ambient temperature , pressure, and relative
humidity were examined on the O2 consumption and respiratory heat loss
rates.
● Besides, the chemical process simulator was used to perform more
accurate mass and energy balances on the lungs and determine the effect
of infection on another function of the respiratory system ie., body cooling.

8. Getting Started into the DWSIM
Unit of Measure: SI Units
Components Defining:
● Nitrogen
● Water
● Carbon Dioxide
● Oxygen
Fluid Package: Peng-Robinson

9. Process Flow Diagram
To perform more accurate mass and energy balances on the lungs, DWSIM was used to simulate the process of respiration. The feed
stream represents the inspired air at Ambient temperature, pressure, and Relative Humidity. The ambient air was heated to body
temperature in a heater, and the sensible heat loss was calculated. The warm humid air was then saturated with water in a vessel,
which facilitated evaporative (latent) heat loss at constant body temperature. While the bottom liquid stream of this unit had no flow
rate (I have added only to fulfill the software requirements), the top gas stream from the lungs was divided by a mass balance operator
into two streams, i.e., exhaled air and consumed O2.

10. Object
Inhaled Humid
Air CO2 from Blood Warm Humid Air Moisture from Lung Tissue
Temperature 20 37 37 37 C
Pressure 1.013 1.013 1.013 1.013 bar
Molar Flow 0.01607 0.00142 0.01607 0.0008862 kmol/h
Molar Flow (Vapor) 0.01607 0.00142 0.01607 0 kmol/h
Molar Fraction (Vapor) / N2 0.7808 0 0.7808 0
Molar Fraction (Vapor) / O2 0.2076 0 0.2076 0
Molar Fraction (Vapor) / CO2 0 1 0 0
Molar Fraction (Vapor) / H2O 0.0116 0 0.0116 1
Object Gas From Lungs Liquid From Lungs Exhaled Air O2 to Blood
Temperature 37 37 37 37 C
Pressure 1.013 1.013 1.013 1.013 bar
Molar Flow 0.0182977 7.85E-05 0.0182644 3.34E-05 kmol/h
Molar Flow (Vapor) 0.0182977 0 0.0182624 3.34E-05 kmol/h
Molar Fraction (Vapor) / N2 0.685738 0 0.687065 0
Molar Fraction (Vapor) / O2 0.182325 0 0.180851 1
Molar Fraction (Vapor) / CO2 0.0776051 0 0.0777552 0
Molar Fraction (Vapor) / H2O 0.0543319 0 0.0543287 0

11. Literature Reference
Hejazi, Bijan, and Keyvan Hejazi. "A
Modeling Study of the Respiratory
System for an Early Intervention of
COVID-19 and Its Transmission."
International Journal of Infection 8.2
(2021).
PFD Fr0m Aspen HYSYS
https://dwsim.fossee.in/flowsheeting-project/dwsim-flowsheet-run/676
Published Simulation File