Mestrado em Engenharia Mecânica
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- ItemAbordagem mista de volumes finitos e elementos finitos para otimização topológica em escoamentos turbulentos(Universidade Federal do Espírito Santo, 2025-02-21) Lima, Caio Patrick Picoli de; Romero Saenz, Juan Sergio ; https://orcid.org/0000-0002-4469-3692; http://lattes.cnpq.br/5239907504083223; https://orcid.org/0009-0002-4851-1494; http://lattes.cnpq.br/3835630925303451; Martins, Ramon Silva ; https://orcid.org/0000-0002-4905-1453; http://lattes.cnpq.br/0642654456195324; Alves, Marcus Vinicius Canhoto ; https://orcid.org/0000-0003-0434-6159; http://lattes.cnpq.br/5750452284147903; Vazzoler Junior, Hermes ; https://orcid.org/0000-0001-7674-1356; http://lattes.cnpq.br/5304698296429834Optimization is a well-known topic in popular imagination. Regarding engineering, geometry optimization is possibly the most widespread topic to the public, especially optimization of aircraft wings, and, as an example of this topic, there is the work of Muller (2021), that, through optimization, almost halved drag on the wing. Another interesting work was conducted by Zheng et al. (2021) in the optimization of the cooling system of a photovoltaic panel, in order to maximize its efficiency. Amongst all optimization methods, the one chosen for this work is the Topological Optimization Method, since it does not depend on a previous knowledge of the optimal geometry. Originally, this method was developed using the Finite Elements Method, which has limitations on flow solution. These limitations are overcome by using the Finite Volumes Method, although it has limitations that prevent its use on the Topological Optimization Method. The objective of this work is the development of the tool created by Lima, Aguiar e Romero (2024), which uses the Finite Volume Method and the Finite Element Method together for Topological Optimization, so that it optimizes turbulent flows. The solution of the flow was done using the software OpenFOAM®, the geometry optimization through custom code executed on Octave, and the automatization of this process was done by Bash Scripting. Once the optimization tests of a nozzle, a T bend, and a 90° knee had been conducted, qualitative analyses with the available literature were conducted. The results obtained were qualitatively identical to the reference geometries with smaller meshes, which shows that the tool is functional, although there is still space for improvement. Furthermore, the geometries resulting from the optimization of turbulent flows had a smaller pressure drop when compared to the geometries generated from the optimization of laminar f lows
- ItemUma avaliação experimental da rota de repotenciação baseada em recuperação de calor residual para o condicionamento do ar de combustão em um motor alternativo de grande porte(Universidade Federal do Espírito Santo, 2024-12-16) Fonseca, Francisco Mello; Donatelli, João Luiz Marcon; Cunha, Carla César Martins; Santos, José Joaquim Conceição Soares; https://orcid.org/0000-0003-3695-2014; Venturini, Osvaldo José; Pérez, Silvia Azucena Nebra deInternal combustion engines (ICEs) in thermal power plants located in regions with high temperatures and humidity, as is the case for some plants in Brazil, operate under preventive derating to avoid the occurrence of knocking. On the other hand, these engines reject a significant amount of heat to the atmosphere, primarily through exhaust gases, which can be recovered to produce chilled water for cooling and dehumidifying intake air, aiming to increase power generation. A research and development project was conducted to design and install an experimental thermal system to evaluate performance improvements in a generating unit of a thermal power plant. This experimental thermal system was designed, its equipment acquired, installed, and instrumented for testing purposes. The system is composed of an absorption chiller, which recovers heat from the engine’s exhaust gases, a cooling coil for conditioning the engine’s intake air, and a cooling tower to cool the chiller and assist the engine radiator. The described experimental thermal system was installed and coupled to one of the generating units equipped with a Wärtsilä 20V34SG engine, which generates 8.5 MW of electric power, considering the derating conditions caused by the hot and humid climate at the plant site. Two experimental test campaigns were conducted. This dissertation aims to present and discuss the procedures and results of these tests, demonstrating that during the experiments, the maximum average cylinder pressure – one of the engine’s operational safety limits – was reached when the electric power output was 9.6 MW, representing nearly a 13% increase in power. The installed thermal system achieved a specific investment cost with savings of approximately 28% compared to recent investments in new generating sets, demonstrating the economic feasibility of the project.
- ItemModelagem computacional da formação de torta de filtração em filtros de manga(Universidade Federal do Espírito Santo, 2024-10-25) Zanete, Hóliver Zambon; Rocha, Sandra Mara Santana ; https://orcid.org/0000-0001-8787-7849; http://lattes.cnpq.br/9653853675618723; Siqueira, Renato do Nascimento ; https://orcid.org/; https://orcid.org/0000-0002-8397-8180; http://lattes.cnpq.br/9791817633014124; https://orcid.org/0009-0007-9184-6210; http://lattes.cnpq.br/3841315513918026; Sartim, Rafael ; https://orcid.org/0000-0002-5678-2027; http://lattes.cnpq.br/0380809249444032; Fernandes, Leandro Marochio ; https://orcid.org/0000-0003-4965-7233; http://lattes.cnpq.br/5933630468428555The growing concern about the impacts of atmospheric pollution on the environment has driven the development of efficient technologies for controlling particulate emissions. Among these technologies, bag filters stand out as effective devices for removing particles from gas streams. These filters consist of a set of filter bags, usually made of fabric or felt, that retain solid particles while clean air passes through the filtering medium. As particles deposit on the surface of the filtering medium, they form a layer known as the filtration cake. This cake increases the resistance to airflow, leading to a higher pressure drop in the system. In this context, a detailed understanding of cake formation is essential for the design and optimization of bag filters. In this work, the implementation of a subroutine based on CFD (Computational Fluid Dynamics) was proposed to predict the formation of the filtration cake in bag filters. Darcy’s law was modified to incorporate particle deposition’s effects on the filter media’s surface on its permeability. The developed subroutine was validated against experimental data available in the literature and subsequently applied to a real bag filter. Three different superficial filtration velocities (5, 10, and 15 cm/s) were evaluated. Initially, the simulations were conducted under singlephase flow conditions (without particle injection), allowing for the fluid dynamics analysis at the beginning of the filtration process. Higher filtration velocities resulted in greater pressure drop. Additionally, the effect of the energy equation on the distribution of flow along the filter surface was observed. After the convergence of the single-phase simulations, particles with a diameter of 5,7 µm and a density of 2,79 g/cm3 were injected at a rate of 0,00127 kg/s for 250 seconds. The results indicated that the formation of the cake redistributed the airflow through the bags, promoting uniformity of the flow along the section of the filter element. It was found that the filling of the filtration chamber alters the pressure drop profile at the beginning of filtration and that, after the stabilization of the particle deposition rate, the increase in pressure drop begins to exhibit linear behavior. The identification of preferential zones for cake formation can significantly contribute to the optimization of bag filter designs
- ItemMetamodelagem para análise térmica no torneamento com ferramenta de aço rápido usando redes LSTM(Universidade Federal do Espírito Santo, 2024-12-13) Santos, Hugo dos Anjos; Dutra, Júlio Cesar Sampaio; Silva, Wellington Betencurte da; Macedo, Marcelo Camargo Severo de; Abreu, Luiz Alberto da SilvaThe prediction of temperature distribution during the turning process is essential for optimizing machining operations and extending tool life. This study investigates the application of LSTM neural networks to model the temperature field in turning operations using high-speed steel tools. The research compares numerical simulations conducted with ANSYS® software against simulated data generated by the software, enabling a comprehensive analysis of heat transfer mechanisms. The results reveal that the LSTM neural network is highly effective, achieving low root mean square error (RMSE) values and processing data more efficiently compared to traditional numerical methods. This dissertation proposes a metamodel that maintains prediction accuracy while significantly reducing computational costs compared to conventional simulations. This approach has the potential to enhance thermal monitoring in industrial processes, optimizing production and improving machining quality. Additionally, the study contributes to Sustainable Development Goal (SDG) No. 9 – Industry, Innovation, and Infrastructure – by promoting innovative technologies that strengthen industrial competitiveness and sustainability.
- ItemUma proposta para medição in-line da distribuição do tamanho de gotas em escoamentos de emulsões e seu desempenho(Universidade Federal do Espírito Santo, 2024-12-03) Pimentel, Cláudio Benincá; Loureiro, Bruno Venturini; Ramos, Rogério; https://orcid.org/0000-0003-4493-2435; Siqueira, Renato do Nascimento; Silva, Fabricio Soares daOil production is generally associated with the co-production of water, and its proportion increases as wells mature. Flow disturbances such as bends, valves, and equipment, which are crucial for controlling production in a safe and sustainable manner, increase shear stresses during flow, leading to the formation of stable emulsions due to the breakage of water droplets dispersed in the oil. Stable emulsions are unfavorable for the oil and gas industry as they hinder the phase separation process (oil/gas/water), resulting in higher consumption of chemical inputs and increased maintenance costs. The efficiency of the separation process is associated with the Droplet Size Distribution (DSD). However, most DSD measurement instruments currently operate through sampling, which exposes the emulsion to the risk of altered characteristics during sample handling. In this study, a device is proposed for measuring DSD using in-line optical microscopy, obtaining DSD through a computer vision-based algorithm from micrographs of droplets dispersed in the emulsion. Experimental procedures for commissioning and performance evaluation of the device, comparing it with conventional DSD measurement techniques, are carried out in a laboratory-scale emulsion experimental circuit available at the Center for Studies in Oil&Gas Flow and Measurement- Núcleo de Estudos em Escoamento e Medição de Óleo e Gás (NEMOG/UFES). The results obtained with the device demonstrate its ability to provide accurate in-line DSD information for water-in-oil emulsions, though with a more limited measurement range compared to the laser diffraction technique. The results are assessed using dimensionless numbers such as Reynolds and Weber, allowing for extrapolation across different scales. The developed device stands out for its simplicity, speed of measurement, and capability for in-line monitoring of emulsions.