Enhancing Fire Resistance: A Thermal and Structural Optimization Approach for Fire Door Frame Using Numerical Simulation Margarida Fernandes, Ana Araújo, João Silva, Nelson Rodrigues, Senhorinha Teixeira, et al. Fire, 2026 Fire resistance is a critical aspect of passive fire protection, particularly in door systems that must maintain integrity under extreme conditions. This paper presents the thermal and structural performance of a single-leaf sandwich fire door, with the goal of improving its fire resistance through numerical optimization. An initial numerical assessment identified the door frame as the thermally weakest component, guiding the subsequent optimization process. Then, a one-way coupled transient thermal–structural Finite Element Method (FEM) analysis was performed using Ansys Mechanical to evaluate the influence of frame material, frame geometry, and insulation type and placement on the door frame assembly when exposed to fire. Results show that the frame material plays a decisive role, where aluminum alloys performed poorly, whereas wooden frames significantly reduced temperatures in both the door and frame by approximately 55% relative to the original configuration. Additional improvements were achieved by increasing frame thickness and placing rock wool within the thermal break, resulting in temperature reductions of 58.3% in the door and 57.3% in the frame. However, these thermal improvements had a limited impact on structural deformation, which remained nearly unchanged.
CFD-Driven Design of an Air-Cooling System for Lithium-Ion Battery Packs in a Formula Student Car Filipe Vaz, João Silva, Vítor Monteiro, Francisco Brito Energies, 2025 In the high-performance environment of Formula Student Car racing, effective battery thermal management is crucial for safety, reliability, and performance. This work presents the design and validation of a lightweight, air-based Battery Cooling System (BCS) developed for a Formula Student vehicle. The system addresses the significant thermal loads generated by 528 Molicel P45B lithium-ion cells, arranged in a constrained U-shaped module layout. Using Computational Fluid Dynamics (CFD), the airflow geometry was optimized to deliver uniform cooling across all modules while minimizing aerodynamic drag. Simulations evaluated the system’s performance under various ambient temperatures (25 °C and 30 °C) and airflow velocities (from 16 m/s to 18 m/s), identifying the impact of duct geometry, internal air guides, and airflow distribution on thermal regulation. Results showed that, at nominal ambient temperature (25 °C), all monitored cells stayed below the 60 °C threshold required by FS regulations. At elevated ambient conditions (30 °C), regions above 60 °C appeared within the pack, revealing non-uniform cooling and reduced safety margin. These findings suggest that, while the system complies with current rules, additional design refinements are needed to enhance robustness under harsher conditions. Additionally, these results are specific to a Formula Student application under competition constraints and are not intended to be generalized to production EVs.
Development of a CFD Model to Study the Fundamental Phenomena Associated with Biomass Combustion in a Grate-Fired Boiler João Pedro Silva, Senhorinha Teixeira, José Carlos Teixeira Processes, 2025 Usually, biomass combustion in grate-fired boilers presents significant challenges due to the heterogeneous nature of the fuel, chemical composition variability, and complex thermal and chemical conversion processes along the grate. Accurate modeling of the fuel bed conversion is critical for optimizing combustion performance and reducing emissions. However, detailed bed models are often computationally intensive and time-consuming. To address this issue, the present work details a simplified empirical bed model that is integrated into a 3D computational fluid dynamics (CFD) simulation of a 35 MW industrial grate-fired boiler. The model successfully reproduced the flue gas mass flow rate, temperature, and chemical composition across different grate sections, predicting an average furnace outlet temperature of 994 °C, CO mass fraction of 779 mg/m3, CO2 concentration of 12 vol.%, and O2 concentration of 9.5 vol.%. These results fall within the range reported in recent CFD studies of similar systems and are consistent with operational monitoring data from the same plant. Sensitivity analyses showed that modifying the primary-to-secondary-air split ratio from 79/21 to 40/60 reduced the average CO mass fraction at the furnace outlet by more than 50%. Additionally, the average furnace temperature increased up to 1050 °C, enhancing combustion efficiency. The CFD model also demonstrated that relocating char combustion to later grate sections led to temperature imbalances near the boiler walls, emphasizing the importance of grate-specific conversion profiles. These results underscore the model’s ability to guide air distribution optimization, improve combustion performance, and reduce pollutant emissions in biomass boilers.
Thermogravimetric Assessment and Kinetic Analysis of Forestry Residues Combustion João Pedro Silva, Senhorinha Teixeira, José Carlos Teixeira Energies, 2025 The development of combustion experiments in a controlled environment is essential for comparing different fuels and quantifying the influence of different key parameters. It is fundamental to understand the transport phenomena at the particle level to obtain reliable results and information for further proper biomass combustion modeling of large-scale equipment. Hence, this paper presents a comprehensive analysis of the thermal decomposition and kinetic of eight samples of forest biomass fuels in terms of combustion behavior by using the thermogravimetric analysis (TGA) technique. The tests were carried out in an oxidizing atmosphere at a heating rate between 5 and 100 °C/min up to 900 °C. It was observed that, for all samples, fuel conversion follows a sequence of drying, devolatilization, and char combustion. Furthermore, differences in chemical and physical composition, as well as in structures and their thermal stability, justify the differences observed between the mass-loss curves of the different fuels. For this, the complexity of kinetic study is addressed in this paper by using different approaches: isoconversional and model-fitting methods. However, the use of isoconversional methods proved ineffective for determining reliable kinetic parameters, due to their sensitivity to particle conversion. A significant variation in activation energy was observed during the devolatilization stage, ranging from 47.92 to 101.30 kJ/mol. For the char oxidation stage, it ranged from 14.97 to 35.48 kJ/mol. These results highlight Eucalyptus as the most reactive species among those studied.
Comprehensive Experimental Study of Biomass Conversion Behavior: From Particle Phenomena to Reactor Scale João Silva, Lelis Fraga, Senhorinha Teixeira, José Teixeira Energies, 2024 During biomass combustion in a grate-fired boiler, each particle undergoes a sequence of different reactions, and the phenomena differ from the conversion of a single, thermally thin, particle. Hence, this paper aims to deepen the understanding of biomass conversion processes and provides valuable insights for advancing biomass-based energy systems. Firstly, the weight loss characteristics of the larger particles of eucalyptus, pine, acacia, and olive samples were investigated at different isothermal temperatures in a purpose-built reactor that simulates the devolatilization process in a controllable manner. As opposed to the thermogravimetric analysis using thermally thin particles, it was concluded that all fuels show that the combustion of large particles does not exhibit separate consecutive conversion stages, due to internal diffusion resistance. Furthermore, it was verified that the devolatilization rate depends mainly on the reactor temperature, and, consequently, the mass-loss profile is independent of the biomass type. In addition to these experiments, the composition of the gases over the devolatilization period was analyzed for the main fuel used in power plants, eucalyptus. Once again, a strong correlation to the reactor temperature was observed, with CO2 and CO always being the main devolatilization products. The temperature dependence of both compounds presented an increase from 8 to 13% between 600 and 800 °C for CO, while the CO2 yield only slightly increased from 11 to 12%. These observations were essential to identify the transport phenomena effect and the gaseous products released during the biomass combustion.
A Review of Biomass Thermal Analysis, Kinetics and Product Distribution for Combustion Modeling: From the Micro to Macro Perspective João Silva, Senhorinha Teixeira, José Teixeira Energies, 2023 Driven by its accessibility, extensive availability, and growing environmental consciousness, solid biomass has emerged as a viable alternative to enhance the diversity of renewable energy sources for electricity generation. To understand the phenomena involved in solid biomass conversion, it is necessary not only to understand the stages of the biomass combustion process but also to understand specifically the kinetics of the reaction and the release of the volatiles. The present work presents an overview of the existing literature on several topics related to the biomass combustion process, its characterization, as well as strategies to develop simple and effective models to describe biomass conversion with a view to the future development of numerical simulation models. Since the focus of most of the investigations is the development of a numerical model, a summary and identification of the different model assumptions and problems involved in thermal analysis experiments are presented. This literature review establishes the significance and credibility of the research, providing the main concepts and assumptions with a critique on their validity. Hence, this work provides specific contributions from a multi-scale perspective which can further be extended to provide insights into the design and optimization of biomass combustion technologies, such as boilers and furnaces.
The Influence of Fuel Mix on the Devolatilization of RDF Based Coal Carlos Castro, Cândida Vilarinho, Manuel E. Ferreira, João Silva, Margarida Gonçalves, et al. Proceedings of the 2nd International Conference on Water Energy Food and Sustainability Icowefs 2022, 2023
A brief review on decarbonization and energy transition of Portuguese industry: renewable energies incorporation and efficiency measures Proceedings of ECOS 2022 35th International Conference on Efficiency Cost Optimization Simulation and Environmental Impact of Energy Systems, 2022
DEVELOPMENT OF CFD MODEL TO STUDY THE SPREAD OF WILDFIRES Inês Gonçalves, João Marques, João Pedro Silva, José Carlos Teixeira, Filipe Alvelos, et al. ASME International Mechanical Engineering Congress and Exposition Proceedings Imece, 2022
Decentralized Forest Biomass Residues Thermal Power Plant Potential: An Economic and Environmental Perspective ECOS 2021 34th International Conference on Efficency Cost Optimization Simulation and Environmental Impact of Energy Systems, 2021
Analysis of the different renewable energy sources in the performance of a Stirling engine ECOS 2019 Proceedings of the 32nd International Conference on Efficiency Cost Optimization Simulation and Environmental Impact of Energy Systems, 2019
Simulation of PMV and PPD Thermal Comfort Using EnergyPlus Diogo Esteves, João Silva, Nelson Rodrigues, Luís Martins, José Teixeira, et al. Lecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics, 2019
Application of a biomass combustion model to an industrial boiler ECOS 2018 Proceedings of the 31st International Conference on Efficiency Cost Optimization Simulation and Environmental Impact of Energy Systems, 2018
The effect of the heating and air flow rate on the mass loss of pine wood particles ECOS 2018 Proceedings of the 31st International Conference on Efficiency Cost Optimization Simulation and Environmental Impact of Energy Systems, 2018
Combustion modelling of a 20 kW pellet boiler João Silva, Lelis Fraga, Manuel Eduardo Ferreira, Sergio Chapela, Jacobo Porteiro, et al. ASME International Mechanical Engineering Congress and Exposition Proceedings Imece, 2018
Multiple jet impingement in reflow soldering - A numerical approach Lecture Notes in Engineering and Computer Science, 2018
Energy and exergy analysis of a biomass power plant João Silva, Senhorinha F. Teixeira, Simone Preziati, José Carlos Teixeira ASME International Mechanical Engineering Congress and Exposition Proceedings Imece, 2016
