Article
Energy & Fuels
Hassan Mohanna, Jean-Michel Commandre, Bruno Piriou, Benoit Taupin, Gilles Vaitilingom, David Honore
Summary: Experimental combustion and numerical modeling of raw and torrefied pine and demolition wood particles were conducted to determine the kinetics of devolatilization and oxidation. Different scenarios tested showed minor variations in devolatilization activation energy but significant differences in char oxidation activation energy. The influence of particle volume evolution and drag force models on the derived kinetic parameters were examined, revealing noticeable differences in particle temperature and other properties along the reactor axis.
Article
Energy & Fuels
Asma Ashraf, Hamed Sattar, Shahid Munir
Summary: The study showed that blending coal with agricultural residues can reduce NOx and SO2 emissions, while improving carbon burnout. Addition of different agricultural residues significantly decreased NOx emissions. Co-firing had a positive impact on reducing SO2 emissions, but there may be a risk of sulfur emissions in blends of agricultural residues with coal.
JOURNAL OF THE ENERGY INSTITUTE
(2022)
Article
Energy & Fuels
D. A. Mortari, D. Perondi, G. B. Rossi, J. L. Bonato, M. Godinho, F. M. Pereira
Summary: Water leaching pretreatment effectively removes water-soluble inorganic constituents from RGP and significantly impacts the combustion efficiency of WLGP chars, leading to lower burnout efficiency and increased gas emissions.
Article
Chemistry, Multidisciplinary
Alain Brillard, Patrick Gilot, Jean-Francois Brilhac, Valerie Tschamber
Summary: This study presents a simple model for simulating combustion processes in a drop tube furnace, which is much simpler than other available models. The model assumes that a coal char particle remains spherical during combustion and is based on two differential equations describing the evolution of particle temperature and oxygen concentration with respect to time. This model also provides access to local quantities to characterize the combustion process, and its validity is demonstrated through comparisons with experimental data.
APPLIED SCIENCES-BASEL
(2023)
Article
Energy & Fuels
Xuecheng Tang, Qian Liu, Wenqi Zhong, Tao Wang
Summary: The combination of biomass and oxy-fuel combustion technology is regarded as a key technology for eliminating atmospheric emissions and achieving long-term decarbonization. However, problems such as ash deposition and corrosion caused by alkali metals in biomass have hindered its development. This study analyzed the deposits during biomass oxy-fuel combustion to understand the effects of different factors on ash deposition. It was found that coarse-grained fuels produced more complete inner layer of deposits, while fine-grained fuels increased the mass of deposits. Combustion temperatures below 800°C and higher oxygen fraction showed positive effects on reducing ash deposition.
BIOMASS CONVERSION AND BIOREFINERY
(2023)
Article
Energy & Fuels
Fei Xie, Runmin Wu, Juntao Wei, Xudong Song, Meiyu Shi, Yonghui Bai, Jinyun Li, Weiguang Su, Guangsuo Yu
Summary: This study investigates the combustion process of single coal particles in an O2/CO2 atmosphere using spectral diagnostics technology. The results show that the flame temperature and alkali metal spectral intensity change with reaction time and oxygen fraction. The spectroscopic results also demonstrate that alkali metal atomic emission spectroscopy can be used to characterize the flame temperature.
Article
Energy & Fuels
Ksenia Vershinina, Pavel Strizhak, Vadim Dorokhov, Daniil Romanov
Summary: This study discusses the lab-scale combustion results of complex waste-derived fuel mixtures in different forms, highlighting that low-moisture mixtures based on municipal solid waste are the most effective in increasing the rate of oxidation reaction and reducing the temperature threshold.
Article
Polymer Science
Miriam Cappello, Giovanna Strangis, Patrizia Cinelli, Caterina Camodeca, Sara Filippi, Giovanni Polacco, Maurizia Seggiani
Summary: This study investigated the use of waste vegetable oil as a green compatibilizer precursor for the reactive blending of high-density polyethylene (HDPE) and polyamide-6 (PA6) blends. The results showed that epoxidized waste vegetable oil (EWVO) had a suitable compatibilizing effect in HDPE/PA6 blends with high HDPE content, while it was unsuitable for blends with high PA6 content.
Article
Thermodynamics
Mychelle L. Andrade, Cristina F. Cavalcanti, Dayene L. L. Dantas, Tulio N. Silvestre, Neide Queiroz, Vicente C. Oliveira Costa, Antonia L. Souza
Summary: The blends prepared in this study had a healthier fatty acid composition and higher oxidative stability compared to pure palm oil. The amount of palm oil used in the blends did not affect the formation of trans fatty acids.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Energy & Fuels
Xiaoshuai Wang, Tengda Ma, Yuegang Tang, Rajender Gupta, Harold H. Schobert, Junying Zhang
Summary: The behavior of 12 trace elements associated with pyrite during heat treatment was investigated. Nickel, Cu, Zn, Cr, and Cd were found to be enriched in samples containing syngenetic pyrite, while other elements were more enriched in samples containing epigenetic pyrite. The volatilization of highly volatile elements like Hg and As was complete at high temperatures, while other elements showed different levels of volatilization in different samples. The elements were classified into low, medium, or high volatility groups based on their volatilization behavior.
Article
Thermodynamics
Prashik Manwatkar, Lekha Dhote, Ram Avtar Pandey, Anirban Middey, Sunil Kumar
Summary: The study investigated the co-combustion of coal with distillery sludge waste (DSW) in a laboratory-scale Drop Tube Furnace (DTF) plant. Preliminary testing methods were used to examine the feasibility of combustion and identify burnout efficiency, emitted pollutants, and metal constituents in the ash. The study showed a high degree of correlation between gaseous emissions, combustion efficiency, and the optimal sludge proportion in the DTF under given combustion conditions.
Article
Green & Sustainable Science & Technology
Sai Manoj Rayapureddy, Jonas Matijosius, Alfredas Rimkus, Jacek Caban, Tomasz Slowik
Summary: This article studies the combustion, performance and emission characteristics of Hydrotreated Vegetable Oil and Butanol Fuel blends compared to fossil diesel fuel. HVO is found to have better stability and higher CN due to transesterification, and can reduce emissions while maintaining efficiency. Blending HVO with butanol can match or improve fuel consumption and emissions compared to diesel fuel.
Article
Green & Sustainable Science & Technology
Hsin-Wei Hsu, Yu-Hsuan Chang, Wei-Cheng Wang
Summary: The study evaluated the hydro-conversion processes for producing renewable jet fuel, finding that one-step conversion is best when profit is the main target, but three-step conversion is more suitable when overall economic benefits are considered. Jet fuel price and cooking oil price are key factors influencing profits, while scaling up plant capacity leads to higher economic benefits.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Mechanics
Zhentao Wang, Qian Kong, Bin Li, Jiameng Tian, Kai Yu, Junfeng Wang
Summary: In this study, the instability and breakup process of an electrified jet of anhydrous ethanol in the electrohydrodynamic simple-jet mode are visualized and analyzed. The evolution of the breakup morphology of the charged jet in the simple-jet mode is described, and the operating window of the simple-jet mode is determined to be within a specific range of Weber number and electric Bond number.
Article
Engineering, Environmental
Shenshi Huang, Ruichao Wei, Tian Xie, Jian Wang
Summary: The study found that rapeseed oil residue is the most susceptible to spontaneous ignition and complete decomposition, while soybean oil residue has the lowest critical heat flux and peak value of heat release rate under external heat flux conditions.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Green & Sustainable Science & Technology
Ivo Abrantes, Ana F. Ferreira, Andre Silva, Mario Costa
Summary: The aviation industry has promoted various approaches to reduce CO2 emissions, including improving aircraft technology and using sustainable low-carbon fuels. However, achieving carbon-neutral growth and a 50% reduction in net emissions by 2050 compared to 2005 levels will require a combination of imminent aircraft technologies with a higher introduction of Sustainable Aviation Fuel (SAF). Results show that these goals cannot be met solely by the current strategies, and carbon-neutral growth may only be possible by 2040 with the right combination of technologies and SAF introduction rates.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Mechanics
P. Foltyn, D. Ribeiro, A. Silva, G. Lamanna, B. Weigand
Summary: This study systematically investigates the role of surface wettability on the morphology of droplet impacts, highlighting its significant influence on the receding phase. Through visualization of different wetting behaviors, it is found that decreasing wettability leads to higher receding rates, impacting the maximum spreading diameter as well.
Article
Engineering, Aerospace
Leandro B. Magalhaes, Andre R. R. Silva, Jorge M. M. Barata
Summary: This study focuses on evaluating gas jet topology for different injector conditions using the Reynolds-averaged Navier-Stokes equations, predicting the axial density decay in supercritical nitrogen jets based on the thermal breakup mechanism concept. The results provide a better understanding of the available experimental data.
Article
Engineering, Aerospace
Renato H. Morais, Luis F. F. M. Santos, Andre R. R. Silva, Rui Melicio
Summary: This paper investigates the equilibria, bifurcation of equilibria, and asymptotic stability conditions of a gyrostat satellite in a circular orbit with its gyrostatic moment tangent to the orbital plane and collinear with the orbital speed. The study reveals interesting results regarding the bifurcation of equilibria when the gyrostat angular momentum is aligned with any of the orbital coordinate frames. A symbolic-numerical method is used to obtain polynomial equations for equilibria positions, and the asymptotic stability is tested using the Lyapunov stability theory scheme.
ADVANCES IN SPACE RESEARCH
(2022)
Article
Astronomy & Astrophysics
Renato H. Morais, Luis F. F. M. Santos, Andre R. R. Silva, Rui Melicio
Summary: This study expands knowledge about asteroid impacts in the ocean and their regional environmental consequences. It evaluates the consequences of three asteroid impacts and finds that tsunami waves are the most threatening and influential effect.
Article
Mechanics
P. Foltyn, D. Ribeiro, A. Silva, G. Lamanna, B. Weigand
Summary: The influence of regularly patterned micro-structures on the physical outcomes of droplet impacts is not well understood. This study systematically investigates the morphology of such surfaces and finds that the outcomes of droplet impacts depend on the impact energy, surface wettability, and structure dimensions. The study also discovers that roughness features can both trigger and inhibit splashing, and identifies reproducible arrangements of air entrapment within the structure.
Article
Mechanics
D. Ribeiro, A. R. R. Silva, M. R. O. Panao
Summary: The phenomenon of bubble encapsulation occurs when droplets impact a liquid film under specific conditions, but there is currently no established criterion for predicting its onset. Visualization of the phenomenon from two perspectives, the common lateral perspective and a bottom perspective, provides insights into the dynamics and formation mechanisms. The bottom shadowgraphs show capillary wavy patterns and perturbations in the liquid film, suggesting a significant role in the onset of bubble encapsulation. The criterion for the onset of bubble encapsulation is based on drop characteristics and properties in the Reynolds number and liquid film thickness and thermophysical properties in the Ohnesorge number.
Article
Engineering, Aerospace
Leandro B. Magalhaes, Andre R. R. Silva, Jorge M. M. Barata
Summary: This document addresses the modeling of fluids in the supercritical regime, specifically in liquid-propelled rocket engines. Nitrogen is used as a surrogate for oxygen-hydrogen mixture to investigate turbulence mixing without combustion and chemical reactions. The temperature field validation for nitrogen coaxial injection at supercritical conditions is crucial for the stable operation of liquid rocket motors.
Article
Thermodynamics
Daniel A. Vasconcelos, Andre R. R. Silva, Jorge M. M. Barata
Summary: This study evaluates the influence of liquid film temperature on crater and jet dynamics. The results show that temperature differences promote the formation of recirculation zones near the impact surface and the crater boundaries, as well as influence the shape and curvature of the crater.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2023)
Article
Mechanics
Daniela F. S. Ribeiro, Miguel R. O. Panao, Jorge M. M. Barata, Andre R. R. Silva
Summary: The goal of this study is to investigate the mechanism of bubble encapsulation when a drop impacts a thin liquid film. The results show that the mechanism consists of two stages. In the first stage, the drop impacts the liquid film, causing a prompt splash and a crown splash. The collapsing crown-bounding rim encapsulates air, forming a bubble. In the second stage, three different phenomena of bubble encapsulation can occur. The study also examines the first perturbation imposed by the drop impact and proposes an empirical correlation for its propagation velocity. Additionally, the geometry of the bubble is investigated.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2023)
Article
Engineering, Aerospace
Emanuel A. R. Camacho, Andre R. R. Silva, Flavio D. Marques
Summary: This paper investigates the aerodynamic characteristics of oscillating airfoils, comparing the performance of a modified version of the NACA0012 with the standard flapping method. By employing a gradient-based optimization method, the study identifies pitching amplitudes that maximize propulsive power and efficiency. The results indicate that the proposed flapping method shows more potential and achieves higher thrust, with near-optimal efficiency, compared to conventional methods.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING
(2023)
Article
Engineering, Aerospace
Emanuel A. R. Camacho, Flavio D. Marques, Andre R. R. Silva
Summary: The present study focuses on the importance of leading-edge dynamic incidence in the propulsive performance of flapping airfoils. By adding a pitching leading-edge to a conventional NACA0012 airfoil, the propulsive characteristics can be improved. Numerical results show that the leading-edge pitching amplitude greatly affects the propulsive power and efficiency, providing significant improvements.
Article
Engineering, Aerospace
Leandro B. Magalhaes, Andre R. R. Silva, Jorge M. M. Barata
Summary: Supercritical nitrogen jet behavior is simulated using a variable density approach, considering heat transfer in the injector. The proposed methodology's suitability for simulating supercritical injection behavior is validated through comparisons with experimental data and compressible formulations from the literature.
Proceedings Paper
Engineering, Aerospace
Joel Filho, Paulo Gordo, Nuno Peixinho, Ricardo Gafeira, Rui Melicio, Andre Silva
Summary: This paper evaluates the possibility of running space debris algorithms on a star tracker device. A breadboard prototype was developed and tested, and a dual-purpose star tracker with stars detection and optical debris detection capability is proposed. This research is of major importance as it addresses the need for detecting space debris.
12TH EASN INTERNATIONAL CONFERENCE ON INNOVATION IN AVIATION & SPACE FOR OPENING NEW HORIZONS
(2023)
Article
Engineering, Aerospace
Ruben Meireles, Leandro Magalhaes, Andre Silva, Jorge Barata
Summary: This paper presents a tool developed in-house for modeling free-falling water droplet cooling processes, utilizing a two-way coupling model and stochastic separated flow technique. The study focuses on the interactions between water droplets and carrier fluid at different humidity ratios, with consideration for heat and mass transfer coefficients and vibrations.
