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Abstract(s)
Prever a disseminação de gotículas respiratórias pode ser um fator importante na prevenção da disseminação de doenças transmitidas pelo ar em diversos ambientes. Assim sendo, neste trabalho era pretendido desenvolver uma ferramenta animada que permitisse a simulação e análise da dispersão de gotículas respiratórias em diferentes ambientes. Fundamentalmente, a ferramenta era composta por 4 softwares interligados, onde para executar as referidas simulações foi necessário realizar 2 etapas, em primeira instância, foi necessário simular o escoamento de ar desenvolvido no interior da sala, e, posteriormente, procedeu-se à simulação do escoamento das partículas respiratórias nessa mesma sala. Para criar o espaço físico a ser simulado, bem como para implementar as condições de fronteira inerentes à simulação, foi empregue o software DesignBuilder. Para efetuar as simulações do escoamento de ar, bem como para executar as simulações de escoamento de partículas, utilizou-se o software de CFD (Mecânica de Fluidos Computacional) OpenFOAM. Na etapa do pós-processamento dos resultados gerados nas simulações, foi utilizado o software ParaView, permitindo a melhor observação das linhas de corrente desenvolvidas no interior do espaço físico, bem como da distribuição das partículas. Para analisar os resultados das simulações, foram compilados uma série de scripts gerados pelo ParaView, sendo posteriormente exportados para folhas Excel, permitindo a elaboração de gráficos. Por forma a avaliar o desempenho da ferramenta foram desenvolvidas uma série de simulações CFD, tanto de escoamento de ar, como de escoamento de partículas emitidas em diferentes regimes de respiração (espirro, tosse, respiração em repouso, situação de falar), simulados em modelos com configurações distintas e uma comparação entre elas foi estabelecida. Verificou-se, portanto, que nos casos em que o ocupante espirrava, o sistema de ventilação foi mais eficiente na remoção de partículas, e no modelo 8, na totalidade dos casos, foi onde se verificou uma maior remoção das partículas por parte do sistema de ventilação. Por oposição, o modelo 5 foi aquele onde o sistema de ventilação foi menos eficiente na remoção de partículas. Como era expectável, observou-se ainda que nos modelos sem ventilação (2 e 4), existia um maior risco de infeção para os ocupantes em comparação como os restantes modelos. Os resultados das simulações mostraram que a ferramenta teve um bom desempenho, permitindo retirar algumas conclusões, tais como a eficiência do sistema de ventilação implementado em cada simulação, quais as superfícies dentro da sala que foram mais contaminadas, ou em qual dos ambientes simulados os ocupantes foram mais infetados. Não obstante de se terem retirado todas as conclusões supracitadas, a ferramenta ainda se encontra na sua fase embrionária, sendo necessário melhorá-la em termos de automatismo entre os softwares e maior capacidade de discretizar os resultados do pós-processamento.
Predicting the spread of respiratory droplets can be an important factor in preventing the dissemination of airborne diseases in different environments. As such, in this work it is presented the initial creation of an animated tool that allows the simulation and analysis of respiratory droplets’ dissemination in different environments. Fundamentally the tool created was composed of 4 interconnected software, and to execute the referred simulations it was necessary to perform 2 steps, first it’s necessary to simulate the airflow developed inside the room, and subsequently the respiratory droplets’ propagation. Firstly, to create the physical space to be simulated as well as to implement the CFD (Computational Fluid Dynamics) boundaries inherent to the simulation, DesignBuilder was operated. Then, to start off the airflow simulation as well as to run the particle flow simulations OpenFOAM was employed. To perform the post-processing of the results generated in the simulations, ParaView was employed allowing the better observation of the streamlines developed inside the physical space as well as the particles’ distribution. To obtain the output of the tool, it was compiled a series of scripts generated by Paraview that were disposed in an Excel spreadsheet, followed by the elaboration of charts which demonstrated the particles’ behaviour inside the simulated models. To evaluate the tool’s performance a series of airflow and particle flow CFD simulations were performed in models with different settings and a comparison between them was established. It was, therefore, verified that in cases where the occupant sneezed, the ventilation system was more efficient in removing particles, and in model 8, in all breathing regime cases, the ventilation system was more efficient in terms of particle removal efficiency. In opposition, model 5 was the one where the ventilation system was less efficient in removing particles. As expected, it was also observed that in the models without a ventilation system (2 and 4), there was a greater risk of infection for the occupants compared to the other models.The results of the simulations showed that the tool performed well, thus allowing the withdraw of some conclusions such as the ventilation system efficiency, which surfaces inside the room were most contaminated, or in which scenario the occupants were most infected. Nevertheless, the tool’s outcome is still rudimentary, as it is still required to upgrade it in terms of automatism between the software and greater ability to discretize post-processing results.
Predicting the spread of respiratory droplets can be an important factor in preventing the dissemination of airborne diseases in different environments. As such, in this work it is presented the initial creation of an animated tool that allows the simulation and analysis of respiratory droplets’ dissemination in different environments. Fundamentally the tool created was composed of 4 interconnected software, and to execute the referred simulations it was necessary to perform 2 steps, first it’s necessary to simulate the airflow developed inside the room, and subsequently the respiratory droplets’ propagation. Firstly, to create the physical space to be simulated as well as to implement the CFD (Computational Fluid Dynamics) boundaries inherent to the simulation, DesignBuilder was operated. Then, to start off the airflow simulation as well as to run the particle flow simulations OpenFOAM was employed. To perform the post-processing of the results generated in the simulations, ParaView was employed allowing the better observation of the streamlines developed inside the physical space as well as the particles’ distribution. To obtain the output of the tool, it was compiled a series of scripts generated by Paraview that were disposed in an Excel spreadsheet, followed by the elaboration of charts which demonstrated the particles’ behaviour inside the simulated models. To evaluate the tool’s performance a series of airflow and particle flow CFD simulations were performed in models with different settings and a comparison between them was established. It was, therefore, verified that in cases where the occupant sneezed, the ventilation system was more efficient in removing particles, and in model 8, in all breathing regime cases, the ventilation system was more efficient in terms of particle removal efficiency. In opposition, model 5 was the one where the ventilation system was less efficient in removing particles. As expected, it was also observed that in the models without a ventilation system (2 and 4), there was a greater risk of infection for the occupants compared to the other models.The results of the simulations showed that the tool performed well, thus allowing the withdraw of some conclusions such as the ventilation system efficiency, which surfaces inside the room were most contaminated, or in which scenario the occupants were most infected. Nevertheless, the tool’s outcome is still rudimentary, as it is still required to upgrade it in terms of automatism between the software and greater ability to discretize post-processing results.
Description
Dissertação de natureza científica para obtenção do grau de Mestre em Engenharia Mecânica
Keywords
Simulação CFD Partículas respiratórias Escoamento de ar Escoamento de partículas Regimes de respiração Modelos CFD CFD simulation Respiratory droplets Airflow Particle flow Breathing regimes CFD models
Citation
MANÉ, Júnior Abdulai Romão - Construção de uma ferramenta de ambiente gráfico animado para simulação de propagação de gotículas. Lisboa: Instituto Superior de Engenharia de Lisboa, 2022. Dissertação de Mestrado