**5. Conclusion**

The aeronautical project quality is essential for providing passengers with acceptable environmental conditions in order to achieve their thermal comfort. The research demonstrates the utmost importance of the aeronautical community (industries, research labs, and universities) in the fluids modeling field and the practical applications in the industry's daily job.

This research results present models based on Computational Fluid Dynamics (CFD) with parameters analysis of temperature and airspeed distributed in a real environment with a cabin sometimes empty, sometimes with passengers standing and/or seated.

It was verified that the temperature and airspeed are influenced by passengers' behavior, whether they are seated or standing in the plane's cabin. Breathing influences the airflow, being able to cause contamination in its environment. So, ventilation from the roof of the cabin promotes more particle dispersion throughout its area.

Another significant aspect to highlight is the importance of achieving the plane's thermal comfort in a cruise. Having an adequate air conditioning system that contributes to the well-being, health, and the aircraft's users' health, as well as the other aspects that influence the passengers' environmental comfort, when based on the cabins' geometry, the armchairs positioning and ergonomics will also contribute

positively in the aircraft's mechanic system. We suggest the use of the air insufflation systems to avoid contamination through the air in the interior of the cabin.

As this research's results demonstrate, simulations in CFD showed that there are three variables, and they must be considered to better evaluate the thermal comfort and indoor air quality in an aircraft cabin, which are- the profile of different temperatures, the airspeed, and human breathing. Therefore, the airflow circulation from the upper (ceiling) to the lower air supply duct (floor) promotes a wider dispersion of particles throughout the cabin that is associated with the characteristics of the mixing of this ventilation through passengers and the airplane's seats. However, it is also important to investigate the airspeed and temperature associated with air humidity.

The use of personalized ventilation is important during the pandemic period of COVID-19, for instance, when the gasper is opened, the airflow must pass between passengers, the air circulation must be oriented directed to the floor's lower duct. Another precaution that helps to protect the passengers is the use of masks and facial protectors during the flights, which must have non-ventilation and be approved by government agencies. Another security measure adopted to protect the people is to remain at a distance from others and always use alcohol gel.

The concern with passenger air transport relates to public health and safety aspects which must be analyzed in order to have a faster response for such risks. This is fundamental so that measures, such as prevention and vaccine development, in addition to efforts to mitigate COVID-19 transmission and dissemination, can be effective. Technical and scientific researches, as well as public policies to aid and enforce these measures must be constant and applied to the aeronautics industry everywhere in the world, with decisions made according to international health regulations. An additional investigation must be carried on about contamination of material carried in the aircraft.

#### **Acknowledgements**

English version by: Samantha A.L. Takatui, Mayor Edson da Silva and Eng. Nilson Carneiro, Prefeitura Municipal de Araraquara, São Paulo, Universidade Federal de São Carlos, PPGEU, Instituto de Pesquisa Tecnológica do Estado de São Paulo, IPT e Universidade de São Paulo, São Carlos.

### **Funding**

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

*Aeronautics - New Advances*
