Article
Energy & Fuels
Samuel Cowart, Gautham Krishnamoorthy
Summary: A methodology for modeling soot production in ethylene-O-2/CO2 diffusion flames based on a skeletal reaction mechanism and the soot nucleation parameter C-alpha showed good agreement with measurements. The study revealed that in-flame radiation is influenced by gas-radiative property models, while the overall radiant fraction is impacted by the choice of soot radiative property model.
Article
Thermodynamics
Francisco Cepeda, Rodrigo Demarco, Felipe Escudero, Juan Jose Cruz Villanueva, Gonzalo Carvajal, Andres Fuentes
Summary: This study investigated the relationship between soot concentration and temperature, and provided new data for time-dependent numerical simulations by measuring local radiative heat flux on transient laminar flames. Results showed that forced condition significantly changed soot production, temperature distribution, and radiative properties, enhancing flame radiation.
COMBUSTION AND FLAME
(2022)
Article
Engineering, Chemical
Mohamed el Abbassi, Domenico Lahaye, Cornelis Vuik
Summary: Numerical simulations show that the air-fuel ratio has a significant impact on both wall temperature and thermal NOx emissions in rotary kilns, peaking at the fuel-rich and fuel-lean sides of the stoichiometric AFR, respectively. As the AFR increases, the wall temperature decreases significantly and thermal NOx emissions drop dramatically. However, NOx validation results suggest that the simulation model may be too simplified.
Article
Thermodynamics
Christopher Betrancourt, Damien Aubagnac-Karkar, Xavier Mercier, Abderrahman El-Bakali, Pascale Desgroux
Summary: This study investigates nucleation flames and their contribution to soot formation and growth. Experimental measurements and modeling simulations of flames with different equivalence ratios were conducted. The results show that nucleation flames produce very small-sized soot particles with negligible growth. The study validates the capability of the combustion model to predict soot volume fraction and emphasizes the need for improvements in particle inception modeling.
COMBUSTION AND FLAME
(2022)
Article
Energy & Fuels
Chinonso Ezenwajiaku, Midhat Talibi, Ramanarayanan Balachandran
Summary: This study focuses on the formation and growth characteristics of polycyclic aromatic hydrocarbons (PAHs) in inverse diffusion flames of various hydrocarbon fuels enriched with H-2. The results show that only the addition of H-2 to CH4 significantly reduces PAH concentrations as the flame length increases. Additionally, the growth rate of PAHs remains relatively stable regardless of the fuel bonding, molecular structure, and H:C ratio.
Article
Mathematics
Sergey M. Frolov, Vladislav S. Ivanov, Fedor S. Frolov, Pavel A. Vlasov, Richard Axelbaum, Phillip H. Irace, Grigoriy Yablonsky, Kendyl Waddell
Summary: This article presents the results of the joint American-Russian space experiment conducted on the International Space Station, which aimed to study the mechanisms of soot formation in a spherical diffusion flame under microgravity conditions. The study found that soot formation was mainly concentrated in the region where the local C/O atomic ratio was between 0.32 and 0.44, and the local temperature was greater than 1300-1500 K.
Article
Thermodynamics
Dan Li, Yu Cheng Liu, Shuangfeng Wang
Summary: The study on nozzle-attached flames in laminar non-premixed jets found that the thickness of the fuel/air mixing layer at the flame base is narrow, and the burning speed is much greater than the local gas flow velocity, leading to the halt of partially premixed flame propagation within the mixing layer.
COMBUSTION SCIENCE AND TECHNOLOGY
(2022)
Article
Thermodynamics
Myunggeun Ahn, Taesung Kim, Youngbin Yoon
Summary: A comparative study was conducted on the response characteristics of non-premixed and premixed flames under acoustic excitation conditions. The study found that the flame fluctuation amplitude in non-premixed flames is influenced by the forcing frequency and velocity perturbation intensity, while in premixed flames, there is a linear correlation between flame height and Strouhal number and FTF gain. Furthermore, introducing flame height perturbation parameters can simplify the analysis of heat-release rate.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2022)
Article
Energy & Fuels
Jinpeng Hua, Jianfeng Pan, Feiyang Li, Baowei Fan, Zhongjia Li, Abiodun Oluwaleke Ojo
Summary: This study experimentally and numerically investigated the heat transfer characteristics of a premixed methane-air flame jet impinging on a hemispherical surface. The effects of mixture equivalence ratio, burner to plate distance, mixture Reynolds number, and curvature ratio on heat transfer characteristics were studied. CFD simulations were performed to analyze the heat flux distribution and average heat flux on the impingement surface. Heat transfer efficiency was used to evaluate the thermal performance of the impinging flame jet. The results showed that equivalence ratio had a significant effect on flame height, which influenced heat transfer efficiency. The burner-to-plate distance played a decisive role in heat transfer characteristics, and the best thermal performance was achieved when the flame premixed cone just touched the impingement surface.
Article
Thermodynamics
Hui Man Yang, Ji Hun Yeo, Nam Il Kim
Summary: The injection of a water-biofuel mixture into a condensing boiler was proposed in this study, aiming to achieve higher thermal efficiency and lower NOx emission. The results showed that blending water with a miscible biofuel can reduce CO2 emission and improve the combustion performances required for commercial condensing boilers.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2022)
Article
Engineering, Aerospace
Hui Ying Wang
Summary: This study investigates non-premixed boundary combustion representative of fire in microgravity environment. Numerical simulations are conducted to evaluate the effects of different fuels on chemical emissions and flame characteristics. The results reveal that the physical properties of fuels play a crucial role in determining flame behavior.
MICROGRAVITY SCIENCE AND TECHNOLOGY
(2022)
Article
Thermodynamics
Phillip R. Johnson, Rajan K. Chakrabarty, Benjamin M. Kumfer
Summary: This study introduces a novel modeling approach to address the unique flame characteristics and soot formation effects in high-Z(st) environments. The model demonstrates robustness and applicability, successfully predicting soot volume fraction profiles and the first-ever prediction of the blue limit condition in a counterflow flame system.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Hernando Maldonado Colman, Alberto Cuoci, Nasser Darabiha, Benoit Fiorina
Summary: Modeling soot formation is a challenging task, and the innovative virtual chemistry approach provides a new optimized global method for simulating turbulent sooting flames. This approach optimizes thermochemical parameters to describe combustion systems, trains thermochemical properties using genetic algorithms, reduces computational costs, and effectively predicts combustion system characteristics.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Maria Castela, Alam Garciduenas Correa, Jason S. Damazo, Deanna A. Lacoste
Summary: Experimental study on thermoacoustic coupling of methane flames in small diameter tubes revealed that thermoacoustic instability impacts flame propagation and can lead to flame quenching. Depending on the tube length (acoustics), flames either fully propagate or extinguish prematurely.
COMBUSTION AND FLAME
(2021)
Article
Green & Sustainable Science & Technology
Zhansheng Shi, Ali Mohammad Ranjbar, Saeed Shayanseresht, Khashayar Danesh Narooei, Mohammad Taghi Fouladvand, Lijuan Deng, Qingang Xiong
Summary: The study introduced a numerical model for simulating the preparation of TiO2 through non-premixed combustion of Ti particles in a counter-flow arrangement. It found that heat loss significantly affects the spatial distributions of temperature and species mass fractions, shortening the distances between flame fronts and stagnation plane, as well as affecting melting and vaporization fronts.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2021)
Article
Engineering, Civil
Mhd Anwar Orabi, Aatif Ali Khan, Liming Jiang, Tejeswar Yarlagadda, Jose Torero, Asif Usmani
Summary: This paper introduces the necessary considerations for the performance of tall, composite, and complex buildings in fire, and highlights recent advancements in numerical simulation. By integrating these advancements into a unified simulation environment, the necessity and efficiency of the developed simulation environment for thermomechanical simulation of composite structures in fire are demonstrated.
ENGINEERING STRUCTURES
(2022)
Article
Engineering, Civil
David Lange, Jose L. Torero, Graham Spinardi, Angus Law, Peter Johnson, Ashley Brinson, Cristian Maluk, Juan P. Hidalgo, Michael Woodrow
Summary: This paper discusses the motivation for stronger accreditation of fire safety engineers and proposes a competency framework to meet the current needs of the public.
FIRE SAFETY JOURNAL
(2022)
Article
Thermodynamics
Roberto Parot, Jose Ignacio Rivera, Pedro Reszka, Jose Luis Torero, Andres Fuentes
Summary: This study proposes a general model to predict the ignition delay time of solid fuels under different fire conditions. Four different heat flux behaviors are considered, and both exact and approximate solutions are provided. The model shows good adaptability when dealing with high heat fluxes.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Siyao Jia, Longhua Hu, Yuxuan Ma, Xiaolei Zhang, Osamu Fujita
Summary: This study investigates the downward flame spread and extinction over inclined electrical wire under horizontal wind. The results show a non-monotonic trend of flame spread rate with increasing horizontal wind velocity, identifying four different regimes based on heat transfer mechanisms. The flame spread rate of Cu-core wire and NiCr-core wire exhibit different dependencies on inclination angle, showcasing enhanced quenching effect and weakened blow-off effect with increased inclination angle.
COMBUSTION AND FLAME
(2022)
Review
Engineering, Civil
Hangyu Xu, Ian Pope, Vinny Gupta, Jaime Cadena, Jeronimo Carrascal, David Lange, Martyn S. McLaggan, Julian Mendez, Andres Osorio, Angela Solarte, Diana Soriguer, Jose L. Torero, Felix Wiesner, Abdulrahman Zaben, Juan P. Hidalgo
Summary: Fire safety is a major challenge for engineered timber buildings due to their combustible nature. This paper presents a literature review and the design of a large-scale testing methodology to establish the fundamental principles for the self-extinction of engineered timber. Research at material and compartment scales has quantified self-extinction and demonstrated the complex phenomena involved, providing insights for the design framework.
FIRE SAFETY JOURNAL
(2022)
Article
Thermodynamics
Yushin Naito, Nozomu Hashimoto, Osamu Fujita
Summary: We developed a droplet evaporation model for a multi-component fuel, considering the nonuniform distributions of both mass fraction and temperature inside the droplet. The accuracy of the model was verified by comparing the predicted droplet lifetimes with experimental results, showing that considering the pre-evaporation process and the internal distribution of mass fraction and temperature improves the accuracy of droplet lifetime prediction. The study also highlighted the importance of considering the nonuniform distributions in practical spray combustion simulations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Yu Xia, Nozomu Hashimoto, Osamu Fujita
Summary: Ammonia is a promising energy carrier for a carbon-neutral society, and solid particle cloud-ammonia co-combustion is an efficient method for reducing CO2 emissions in the thermal power generation sector. However, the turbulent flame propagation mechanism of this co-combustion process is still unknown. In this study, experiments were conducted to investigate and validate the general turbulent flame propagation mechanism of solid particle cloud-ammonia co-combustion. The results showed that the flame propagation velocity is influenced by the equivalence ratio of ammonia-oxidizer. Based on these findings, new numerical simulation models can be developed for solid particle cloud-ammonia co-combustion in the future.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Yusuke Konno, Yutao Li, Jean -Marie Citerne, Guillaume Legros, Augustin Guibaud, Nozomu Hashimoto, Osamu Fujita
Summary: This study investigates the downward/opposed flame spread over laboratory wire samples under varied gravity conditions. Reduced gravity experiments were conducted using parabolic flights. The limiting oxygen concentrations (LOCs) and flame spread rates (V-f) were measured as a function of gravity level, oxygen concentration, forced flow velocity, and wire characteristics. The experimental data provide valuable information on the flammability of materials in a partial gravity environment and can be used for fire safety design in future space exploration.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Feng Guo, Seiya Kawaguchi, Nozomu Hashimoto, Osamu Fujita
Summary: This study investigates the overload ignition of polymer insulated wires in microgravity and provides basic information for space fire safety. The focus is on the effect of pyrolysis kinetic parameters of the insulation material on ignition characteristics. Two-dimensional numerical simulations and microgravity experiments are used for model validation. The results show the significance of activation energy and pre-exponential factor on ignition delay time and minimum ignition energy, as well as their impact on ignition modes under continuous overloading.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Chemistry, Multidisciplinary
Thong D. Hong, Iman K. Reksowardojo, Tatang H. Soerawidjaja, Osamu Fujita
Summary: This study investigates the performances, emissions, and soot formations of a gas turbine engine fueled with kerosene and its mixture with bioparaffins. The results show that the mixture performs similarly to kerosene in terms of performance, but has slightly higher NOx emissions. Kerosene, on the other hand, has slightly higher CO and HC emissions compared to the mixture. The findings encourage further engine and flight tests.
Article
Thermodynamics
Sandra L. Olson, Gary A. Ruff, Paul V. Ferkul, Jay C. Owens, John Easton, Ya -Ting Liao, James S. T'ien, Balazs Toth, Grunde Jomaas, Carlos Fernandez-Pello, Guillaume Legros, Augustin Guibaud, Osamu Fujita, Nikolay Smirnov, David L. Urban
Summary: This study presents concurrent flame spread data for thermally-thin charring solid fuels in habitable spacecraft. The experiments show that duct size strongly affects flame spread rates and flame lengths. The observed transient excess pyrolysis length is hypothesized to be a post-ignition flame growth transient for two-dimensional flames.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Andrea Lucherini, Juan P. Hidalgo, Jose L. Torero, Cristian Maluk
Summary: This research study presents a heat transfer model for estimating the thermal and physical response of intumescent coatings. The study demonstrates the importance of coating swelling and thermal conditions at the coating-substrate interface in governing heat conduction within intumescent coatings.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Yu Xia, Nozomu Hashimoto, Osamu Fujita
Summary: Ammonia is a highly promising energy carrier for achieving a carbon-neutral society. The co-combustion of solid particle clouds-ammonia is considered an efficient method of reducing carbon dioxide emissions. Understanding the turbulent flame stabilization and extinguishment processes during this co-combustion is essential for its application in combustors.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Qiang Wang, Xuan Liang, Aquan Lu, Ben Wang, Osamu Fujita, Suk Ho Chung, Longhua Hu
Summary: The blowout behavior of inclined nonpremixed turbulent jet flames is investigated by varying the jet inclined angle. Experimental quantification of the blowout limit and numerical simulations are performed to analyze the flow field difference for different inclined angles. Physical modeling and analysis are conducted to understand the effect of inclined angle on blowout behavior. The findings provide new insights into the blowout limit of nonpremixed inclined turbulent jet flames and propose a model to characterize this behavior.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Engineering, Civil
Andrea Franchini, Carmine Galasso, Jose L. Torero
Summary: This paper introduces a structural design optimization methodology for minimizing the consequences of a fire. The methodology considers the trade-off between implementing passive fire protection measures and enhancing a structure's inherent fire capacity. The feasibility of the methodology is demonstrated through a case study on the fire safety design of a steel girder bridge. The optimization process generates multiple Pareto-optimal solutions for minimizing the maximum bridge deflection after a given fire exposure time.
FIRE SAFETY JOURNAL
(2023)
