Avaliação experimental e computacional da dinâmica dos fluídos de um bioesterilizador para descontaminação ambiental e de pessoas.

Abstract

Coronavirus, of the subgenus Betacoronavirus, was isolated for the first time in the city of Wuhan (China), in December 2019, from a group of patients presenting with an

unrecognizable acute pneumonia. The transmission of the disease linked to SARS- CoV-2 infections is associated with contact with infected people through the emission

of respiratory fluids, in the form of droplets. The present work aims to evaluate, by experimental and computational methods, the fluid dynamics of a bio-sterilizer, a device used for environmental and human decontamination and presented as an instrument to combat the transmission of Covid-19. For this, it is proposed to develop the architecture of the steam sterilization system; to measure, via digital temperature sensors, the behavior in stationary and transient states of the system; develop a spatially resolved model using Computational Fluid Dynamics (CFD) to determine the transfer of heat and mass within the control volume; validate the simulated temperature gradients by comparison with the data obtained experimentally; and, finally, determine the speed profile, pressure gradients and steam distribution inside the sterilization cabin. To achieve this objective and its consequences, methods of experimentation and computational simulation are applied. Experimentally, digital temperature sensors are used in the geometry of the biosterilizer device (composed of a cabin and a steam diffuser), measured by time and by position, over three tests in triplicate, at temperatures other than 40 °C, 45 °C and 50 °C. Computationally, using ANSYS Fluent software for fluid dynamic analysis. As a next step, empirical data and temperature simulations are compared statistically. As a result, it appears that, among the three tests carried out, the second (assignment of input temperature parameter set at 45 ° C) presents better thermal comfort to the user of the cabin and guarantees a minimum average temperature for the deterioration of microbial forms. From the results obtained, it is concluded that there is a convergence between the simulated temperature measurements and their experimental measurements inside the

1 biosterilizer cabin, which validates the first ones. The differences between the measured and simulated temperatures are below 0.4 K, with an average error of less than 0.5%, which is below the accuracy of the temperature sensor. Finally, this work presents a computational tool developed for a steam sterilizer capable of predicting the temperature of the fluid and its gradients along the geometry and of evaluating the production and quality of the steam, as well as analyzing the distribution of steam in it.