Article
Thermodynamics
Haiou Wang, Zhuo Wang, Kun Luo, Evatt R. Hawkes, Jacqueline H. Chen, Jianren Fan
Summary: In this study, premixed combustion in a turbulent boundary layer under auto-ignitive conditions was investigated using direct numerical simulation (DNS). The research found that combustion significantly modified near-wall turbulent structures and resulted in reaction front wrinkling in both the free stream and within the boundary layer. Different combustion modes were observed in various regions, with flame propagation prevailing in the near-wall region and auto-ignition becoming more important as the wall-normal distance increases.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Edouard Suillaud, Karine Truffin, Olivier Colin, Denis Veynante
Summary: An a priori model for premixed turbulent flame combustion in the thin reaction zone (TRZ) regime is proposed, deduced from analysis of direct numerical simulation (DNS) data. The model considers the effects of turbulence and differential diffusion on the flame, and is validated through DNS.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Xinjie Huang, Gongjian Chen, Zhijie Zhou, Junjie Hu, Changlong Wang, Depeng Chen
Summary: The study found that altitude has an impact on flame spread of melted material, with higher altitudes resulting in decreased flame spread rate. Different behaviors of flame spread were observed at low and high altitudes, with accelerated spread rate at low altitude and stagnancy of pyrolysis front at high altitude.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Andrea Gruber, Mirko R. Bothien, Andrea Ciani, Konduri Aditya, Jacqueline H. Chen, Forman A. Williams
Summary: Results from Direct Numerical Simulations (DNS) show that compressibility effects play a key role in flame stability in hydrogen reheat combustion, with unstable ignition and combustion consistently encountered near the mixture's characteristic crossover temperature.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Josef Hasslberger, Gulcan Ozel-Erol, Nilanjan Chakraborty, Markus Klein, Stewart Cant
Summary: Three-dimensional carrier-phase Direct Numerical Simulations (DNS) combined with a Lagrangian representation of individual droplets were used to study the physical effects of liquid water mist interacting with laminar and turbulent premixed stoichiometric n-heptane/air flames. The study found that water droplets significantly reduce flame temperature and burning velocity, with the droplet size having a strongly non-linear impact on overall burning rate, while water loading has a more linear influence. The investigation also focused on the different regimes of droplet-flame interaction, particularly the influence of latent heat of vaporization.
COMBUSTION AND FLAME
(2021)
Article
Chemistry, Multidisciplinary
Dushyant M. Chaudhari, Stanislav I. Stoliarov, Mark W. Beach, Kali A. Suryadevara
Summary: This study systematically investigated the combustion properties of polyisocyanurate foam, analyzing its thermal properties through experiments and modeling. The significant influence of the blowing agent on flammability was discovered, and a complete pyrolysis property set accurately predicted various measurements. The developed modeling approach successfully predicted the evolution of heat release rate in full-scale flame spread tests on the PIR foam.
APPLIED SCIENCES-BASEL
(2021)
Article
Thermodynamics
Shengfeng Luo, Bo He, Yanli Zhao, Hui Zhang
Summary: This study numerically investigated the ignition and steady-state flame spread behaviors of a vertical solid fuel in normal gravity and static environment using the lattice Boltzmann method and finite difference method. The results showed that the flame developed from a point flame into an asymmetric arch-shaped flame, which eventually separated in the downstream zone under the influence of buoyant flow and disappeared at the downstream boundary.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Haiou Wang, Guo Chen, Kun Luo, Evatt R. Hawkes, Jacqueline H. Chen, Jianren Fan
Summary: In this study, three-dimensional turbulent non-premixed oblique slot-jet flames impinging at a wall were investigated using direct numerical simulation (DNS). The flame extinction and reignition behavior were found to differ between cases with different Damköhler numbers, while flame/wall interactions and chemical reactions had impacts on flow topologies.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Engineering, Aerospace
Andrej Sternin, Daniel Martinez, Daniel Sternin, Oskar Haidn, Martin Tajmar
Summary: This work aims to provide support for the design of reliable DNSs for statistically planar flames. Improved simulation design strategies are developed, as well as a deterministic calculation strategy for mesh features. Guidelines and measurement techniques are proposed for choosing design parameter values and determining characteristic points within the flame front.
Article
Thermodynamics
D. Kiran, Y. Minamoto, K. Osawa, M. Shimura, M. Tanahashi
Summary: In this study, direct numerical simulations were used to investigate lifted multi-jet flames of hydrogen and steam-diluted oxygen. The simulation data analyzed the structures of the flames and flame bases as well as the flame-base propagation in a configuration similar to a gas turbine with multiple fuel jets. Turbulent multi-jet flames have a single connected base region, which is different from the separate bases of laminar flames. Despite the differences in flame-base characteristics, the propagation speed is similar for both turbulent and laminar multi-jet flames, suggesting the applicability of the well-known flame-base stabilization theory to the multi-jet configuration.
COMBUSTION SCIENCE AND TECHNOLOGY
(2023)
Article
Thermodynamics
Kai Niemietz, Lukas Berger, Michael Huth, Antonio Attili, Heinz Pitsch
Summary: A direct numerical simulation (DNS) with finite rate chemistry was conducted to study the influences on carbon monoxide (CO) emissions in gas turbine combustion. The results showed that the mean strain rate of the turbulent flow, the flame-wall interaction, and the interactions of the flame with the recirculation zones of the flow all affected the formation of CO. The CO production and consumption in the turbulent flame differed significantly from those in a freely propagating flame. The relevant parameters for CO formation and consumption were identified as the local CO mass fraction, wall heat loss, and the mass fraction of the OH radical.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Engineering, Civil
Atul Kumar Joshi, Amit Kumar, Vasudevan Raghavan, S. A. Trubachev, A. G. Shmakov, O. P. Korobeinichev, B. Praveen Kumar
Summary: In this study, downward flame spread over multiple parallel fuel sheets was investigated to understand the non-monotonic trend in flame spread rate with spacing. The flame spread process is influenced by both conduction and radiation heat transfer, with spacing affecting oxygen availability and heat transfer, leading to changes in flame spread rate.
FIRE SAFETY JOURNAL
(2021)
Article
Thermodynamics
Prateep Chatterjee, Dong Zeng, Yi Wang
Summary: A flamelet-based subgrid soot-radiation model is developed to account for varying oxygen concentration, applied in the radiation modeling of buoyant, turbulent diffusion flames. The model is verified against experimental data and shows reasonably good comparison when predicting the radiant emission of turbulent flame-sheets.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Engineering, Multidisciplinary
Xiaoyu Wang, Jing Wang, Jianghua Wang, Guohua Sheng
Summary: This study combines experimental measurements and numerical simulations to analyze the flame spread behavior over wood treated with flame retardants. The results show that the flame retardant-treated wood can reduce the heat release rate, smoke and CO2 concentration, and enhance visibility in case of fire.
Article
Thermodynamics
O. P. Korobeinichev, S. A. Trubachev, A. K. Joshi, A. Kumar, A. A. Paletsky, A. G. Tereshchenko, A. G. Shmakov, R. K. Glaznev, Vasudevan Raghavan, A. M. Mebel
Summary: Experimental and numerical studies were conducted on the downward flame spread over PMMA with and without TPP, showing that TPP can reduce flame spread rate. The research proposed the retardancy capability of TPP on gas-phase reaction through experiments and quantum chemistry calculations.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Yifan Yang, Haodong Zhang, Linye Li, Mingming Gu, Xi Xia, Fei Qi
Summary: This paper investigates the formation of a blue whirl by controlling tangential and radial airflows. By using a unique fire whirl apparatus, the blue whirl can be formed directly upon ignition without going through the transient phase. The study also discovers new flame regimes and explores the mechanism behind the formation and transition of the blue whirl.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Xiaobin Qi, Songyan Gao, Zhiping Zhu, Qinggang Lyu, Haixia Zhang
Summary: This study experimentally investigated the propagation characteristics of reverse combustion under oxygen-limited and enriched conditions. The contribution of volatiles gas-phase oxidation and char surface oxidation to reverse combustion was evaluated. The results showed that oxygen enrichment expanded the operating range of oxygen flow rate for reverse combustion and enhanced the low-temperature oxidation of the solid fuel. The findings provide a better understanding of the driving mechanism of reverse combustion and have important implications for efficient thermal conversion of solid fuels.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Bingjie Chen, Peng Liu, Bingzhi Liu, Zhandong Wang, Xiang Gao, William L. Roberts
Summary: In this study, the low temperature oxidation of 1,2,4-trimethylbenzene was investigated using experiments and numerical simulations. The results showed the presence of toxic oxygenated aromatic compounds and proposed potential formation pathways. The numerical simulations accurately predicted the mole fractions of most compounds, but some compounds were missing.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Meng Sui, Zhiheng Zhu, Fashe Li, Hua Wang
Summary: The effect of adding ferrocene as a combustion catalyst to Jatropha biodiesel on its pyrolysis and combustion performance is investigated. The results show that adding ferrocene reduces activation energy and harmful emissions while improving combustion efficiency.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Manaf Sheyyab, Mohammed Abdulrahman, Subharaj Hossain, Patrick T. Lynch, Eric K. Mayhew, Kenneth Brezinsky
Summary: Fuel surrogates, simplified representations of complex fuels, accurately model speciation results and reaction kinetics, reproduce the ignition quality and chemical functional group compositions of their parent fuels.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Yan Wang, Shumeng Xie, Hannes Bottler, Yiqing Wang, Xinyi Chen, Arne Scholtissek, Christian Hasse, Zheng Chen
Summary: This study investigates how flow affects the ignition and transition process of a cool flame. The results show that the ignition energy determines the highest temperature and the strain rate influences the flame propagation and the transition from cool flame to hot flame.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Tanusree Chatterjee, Mengyuan Wang, Goutham Kukkadapu, Chih-Jen Sung, William J. Pitz
Summary: Cycloalkanes, including cyclohexane, are important hydrocarbons in transportation fuels. However, limited oxidation data at low-to-intermediate temperatures and inadequate predictive ability of kinetic models have hindered the understanding and improvement of cyclohexane oxidation. This study provides experimental and modeling results to develop a more accurate kinetic model for cyclohexane oxidation.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Tao Wu, Erik Hagen, Haiyang Wang, Dylan J. Kline, Michael R. Zachariah, Carole Rossi
Summary: It was found that incorporating CuO into Al/I2O5 can significantly reduce the ignition time and enhance the combustion performance. The optimum composition of 80/20 wt% of I2O5/CuO shows a 30 times shorter ignition time and produces a peak pressure and pressurization rate 4 and 26 times greater than traditional Al/I2O5. A series of characterizations helped unravel the cause of improvement and propose a reaction mechanism for this ternary Al/I2O5/CuO system. This study proposes a facile, inexpensive, and efficient way to enhance the combustion performance of Al/I2O5 biocidal nanoenergetic materials.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Mahmoud Gadalla, Shervin Karimkashi, Islam Kabil, Ossi Kaario, Tianfeng Lu, Ville Vuorinen
Summary: In this study, the flame initiation process in dual-fuel spray assisted combustion is explored through scale-resolved simulations, providing numerical evidence on the initiation of premixed flames. It is found that there is a transient mixed-mode combustion phase after ignition, followed by a primarily deflagrative combustion mode. The interactions between turbulence and premixed flame front are characterized in the corrugated regime.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Neeraj Kumar Pradhan, Arindrajit Chowdhury, Debasis Chakraborty, Neeraj Kumbhakarna
Summary: In this study, a modified model for predicting the burn rate of composite solid propellants is proposed. The model has been validated against experimental and theoretical results, and it outperforms existing models in all cases considered. The model is highly robust and provides results quickly, making it highly efficient in terms of time, effort, and computational resources.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Lili Ye, Zhihe Zhang, Fan Wang, Xiaodong Wang, Yiming Lu, Lei Zhang
Summary: This study investigated the pyrolysis mechanism of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) explosive using ab initio and kinetic modeling simulations. The results showed that N-NO2 bond fission and C-H beta-scission are important channels in the decomposition of HMX.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Andrei N. Lipatnikov, Hsuchew Lee, Peng Dai, Minping Wan, Vladimir A. Sabelnikov
Summary: This study investigates the importance of thermodiffusive and hydrodynamic instabilities of laminar flames in turbulent flows through numerical simulations. The analysis suggests that laminar flame instabilities play a minor role at sufficiently high Karlovitz numbers.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Shijie Xu, Yue Qiu, Leilei Xu, Jianqing Huang, Shen Li, Elna J. K. Nilsson, Zhongshan Li, Weiwei Cai, Marcus Alden, Xue-Song Bai
Summary: Metal powder is a promising carbon-free and recyclable energy carrier. In this study, a computational model for the combustion and phase change of micron-sized iron particles was proposed and validated. The model successfully captures the melting, surface reactions, cooling, and solidification processes. The study also reveals a two-stage solidification phenomenon and identifies a diffusion-controlled mechanism during the melting process. The reaction between iron and CH4/O2/N2 flame products is found to play a significant role in the iron combustion process.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Khalid Aljohani, Abd El-Sabor Mohamed, Haitao Lu, Henry J. Curran, S. Mani Sarathy, Aamir Farooq
Summary: This study investigates the impact of exhaust gas recirculation (EGR) and NOx on the ignition delay time of oxygenated gasoline. A gasoline surrogate model is developed and the experimental data are useful for predicting fuel ignition behavior in internal combustion engines. The results show that EGR inhibits gasoline reactivity, while NOx has a promoting effect at high temperatures. This research is important for understanding the combustion behavior of gasoline in engines.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Chengcheng Ao, Jia Yan, Tong Yan, Lidong Zhang, Pan Wang
Summary: This study investigates the inhibitory effect of ammonia blended with hydrocarbon fuels on soot formation. The results show that there is a chemical interaction between ammonia and polycyclic aromatic hydrocarbons (PAHs), blocking the formation of larger PAHs.
COMBUSTION AND FLAME
(2024)
