-
Novel ultra-low NOx coal combustion technologies based on local microenvironment targeted regulation. Part 1. Selective oxygenation Combust. Flame (IF 4.4) Pub Date : 2024-05-04 Xiuchao Yang, Jiaxun Liu, Guoqing Chen, Zining Zhou, Xinyu Zhong, Jianguo Liu, Xiumin Jiang
-
Multiphase ignition and combustion model and its characteristics of boron particles based on dynamic experimental phenomena Combust. Flame (IF 4.4) Pub Date : 2024-05-04 Xianju Wu, Zhijun Wei
Boron, renowned for its high-energy potential but challenged by combustion difficulties, emerges as an ideal fuel for solid-fuel scramjet engines. This study improved the ignition and combustion model for boron particles in wet air by refining the Penn State University extension models based on the dynamic experimental phenomena. Under atmospheric pressure, the transition in combustion mode for boron
-
A deep insight into catalytic effects of alkali and alkaline earth metals (AAEMs) in coal ash on NH3 oxidation during ammonia and coal co-firing process Combust. Flame (IF 4.4) Pub Date : 2024-05-03 Su Zhang, Yixiang Zhang, Yong Zhang, Yixiang Shu, Liming Cui, Tedla Medhane Embaye, Tao Niu, Yili Zhang, Houzhang Tan, Xuebin Wang
Ammonia as an eco-friendly and carbon-free energy has been greatly concerned at home and abroad. It has been utilized in the ammonia and coal co-firing process, demonstrating robust market viability. Nonetheless, due to the element N within ammonia causing the production of NO, the catalytic effect and reaction mechanics of AAEMs in coal ash on the NH oxidation remain elusive. In this study, the catalytic
-
Experimental and kinetic modeling study on auto-ignition of ammonia/n-heptane mixtures at intermediate temperatures Combust. Flame (IF 4.4) Pub Date : 2024-05-03 Yuan Fang, Wenjing Qu, Liyan Feng
Ignition delay times (IDTs) were measured in a shock tube facility for NH/n-heptane mixtures with NH concentrations in the blending fuel ranging from 0.3 to 0.95 by molar fraction. The measurements were conducted under low pressure of 2 atm and intermediate temperatures of 1350–1500 K at equivalence ratios of 0.5, 1, and 2. With the increase of n-heptane content or equivalence ratio, there is a decrease
-
Shock tube and comprehensive kinetic modeling study of ammonia/diethyl ether (DEE) mixtures Combust. Flame (IF 4.4) Pub Date : 2024-05-03 Lingfeng Dai, Jiacheng Liu, Chun Zou, Qianjin Lin, Tong Jiang, Chao Peng
-
Influence of pyrolysis temperature on carbon deposition from the perspective of volatile evolution during the ex-situ pyrolysis-catalysis of plastic Combust. Flame (IF 4.4) Pub Date : 2024-05-03 Haoyu Xiao, Linyu Zhu, Shujiang Li, Yingquan Chen, Zhongyue Zhou, Haiping Yang, Hanping Chen
To better understand the mechanism of carbon deposition, the ex-situ catalytic pyrolysis of polyethylene (PE) was explored over a FeNi/AlO catalyst, and the evolution of volatiles as well as the yield and structure of carbon products at different temperatures were analyzed in depth by an in-situ atmospheric pressure photoionization high-resolution mass spectrometry (APPI HRMS) combined with a fixed-bed
-
Lift-off characteristics of non-premixed jet flames of CH4 and cracked NH3 mixtures in laminar/turbulent transition Combust. Flame (IF 4.4) Pub Date : 2024-05-03 Dong Seok Jeon, Gyu Jin Hwang, Nam Il Kim
-
Resolving emission factors and formation pathways of organic gaseous compounds from residential combustion of European brown coal Combust. Flame (IF 4.4) Pub Date : 2024-05-02 Anni H. Hartikainen, Satish Basnet, Pasi Yli-Pirilä, Mika Ihalainen, Sini Talvinen, Jarkko Tissari, Santtu Mikkonen, Ralf Zimmermann, Olli Sippula
Residential combustion of brown coal can be an important source of ambient air pollution in areas with abundant brown coal deposits, such as Eastern Europe or China. The exhaust emission contents may vary regionally depending on the fuel composition, calling for detailed characterization of emissions from different coal types. In this work, the organic gaseous emissions of European brown coal combusted
-
Premixed flames in narrow heated channels of circular cross-section: Steady-state solutions, their linear stability analysis and the multiplicity of stable dynamic modes Combust. Flame (IF 4.4) Pub Date : 2024-05-02 Vadim N. Kurdyumov, Daniel Fernández-Galisteo, Carmen Jiménez
-
Laser induced spark ignition of a gaseous methane–oxygen model rocket combustor Combust. Flame (IF 4.4) Pub Date : 2024-05-02 Ryan M. Strelau, Mark D. Frederick, Timothy R. Winter, William C.B. Senior, Rohan M. Gejji, Carson D. Slabaugh
The spatio-temporal evolution of laser induced spark ignition of non-premixed gaseous methane and oxygen is investigated. The reactants are injected into an optically accessible combustion chamber from an oxidizer centered shear-coaxial injector. High-speed schlieren imaging and measurements of laser energy deposited are used to characterize ignition behavior at various spark locations throughout the
-
Revisit the benzene oxidation at elevated pressure Combust. Flame (IF 4.4) Pub Date : 2024-05-01 Xu-Peng Yu, Du Wang, Dong-Xu Tian, Zhen-Yu Tian
The benzene (A) oxidation was examined in a jet-stirred reactor (JSR) within the temperature range of 880–1010 K at 12.0 atm under both fuel lean (Φ = 0.5) and rich (Φ = 3.0) conditions. Eighteen intermediates and products were identified and quantified by gas chromatography (GC) and gas chromatograph-mass spectrometer (GC–MS). A kinetic model comprising 280 species and 1734 reactions was developed
-
Sublimation and oxidation measurements of graphite and carbon black at high temperatures in a shock tube using absorption imaging and thermal emission Combust. Flame (IF 4.4) Pub Date : 2024-04-30 Colton Willhardt, Damon Chen, Kyle Daniel, Daniel Guildenbecher, Nick Glumac
Surface mass loss rates due to sublimation and oxidation at temperatures of 3000–7000 K have been measured in a shock tube for graphite and carbon black (CB) particles. Diagnostics are presented for measuring surface mass loss rates by diffuse backlit illumination extinction imaging and thermal emission. The surface mass loss rate is found by regression fitting extinction and emission signals with
-
Enhance thermal response behavior of energetic composite by doping fluorinated graphene Combust. Flame (IF 4.4) Pub Date : 2024-04-27 Liangjun Xie, Jie Liu, Qingjie Jiao, Xuehui Nie, Hui Ren
Fluorinated graphene (FGO) is a two-dimensional layered compound with thermal conductivity and hydrophobicity. Different percentage of FGO (1.00 wt.%, 3.00 wt.%, 5.00 wt.%) was added to the composite energetic system boron/potassium nitrate (B/KNO). Through elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), the results show that with
-
A numerical study on premixed laminar ammonia/air flames enriched with hydrogen: An analysis on flame–wall interaction Combust. Flame (IF 4.4) Pub Date : 2024-04-26 Parsa Tamadonfar, Shervin Karimkashi, Thorsten Zirwes, Ville Vuorinen, Ossi Kaario
Ammonia (NH) has been recognized as a potential carbon-free synthetic fuel of the near future. To enhance its low reactivity, one practical option is to blend it with hydrogen (H). In this study, the transient head-on quenching of premixed laminar ammonia/air flames enriched with hydrogen is explored based on numerical simulations using detailed chemistry and the mixture-averaged transport model. In
-
Effect of flame characteristics on an isolated ethanol droplet evaporating through stagnation methane/air flames: An experimental and numerical study Combust. Flame (IF 4.4) Pub Date : 2024-04-25 Deniz Kaya Eyice, Mehmet Karaca, Fabien Halter, İskender Gökalp, Christian Chauveau
A single ethanol droplet evaporation through laminar methane/air stagnation flame is investigated at lean, stoichiometric and rich conditions experimentally and numerically. For the droplets having initial diameters of 20-, the particle Reynolds number is measured via PIV/PTV, resulting in the slip velocity between the droplet and gas flow being small and the surrounding gas being able to carry without
-
Influence of lignin on smoldering propagation Combust. Flame (IF 4.4) Pub Date : 2024-04-25 Benjamin D. Smucker, W. Jayani Jayasuriya, Kyle E. Niemeyer, David L. Blunck
Smoldering combustion during wildfires contributes significantly to emissions of pollutants, can burn for days or months, may damage roots and soil, and can transition to flaming combustion. Mitigating these hazards requires an understanding of how physical parameters control smoldering combustion, such as the chemical composition of the fuel. The main organic constituents of biomass are cellulose
-
Uncertainty analysis of soot formation in laminar flames simulated with a sectional method Combust. Flame (IF 4.4) Pub Date : 2024-04-23 Xingyu Su, Matthew J. Cleary, Hua Zhou, Zhuyin Ren, Assaad R. Masri
The uncertainty in soot kinetics parameters will lead to uncertainty in the prediction of soot characteristics, including particle size distribution (PSD) and soot volume fraction (SVF). Uncertainty quantification is an important way to evaluate the model performance not only in terms of nominal accuracy but also in terms of confidence intervals. In this work, an uncertainty analysis approach combined
-
Velocity match between plasma and flame in microwave-assisted spark ignition Combust. Flame (IF 4.4) Pub Date : 2024-04-22 Huimin Wu, Zhaowen Wang, Xiaobei Cheng, Jingxing Xu, Rongjie Li, Xinhua Zhang, Jyh-Yuan Chen
As a prospective ignition technique, microwave-assisted spark ignition (MAI) can accelerate flame and thus satisfy the demand for effective ignition. However, its acceleration mechanism on flame velocity is still unclear, which hinders its application and optimizations. Therefore, this research focuses on understanding the flame acceleration mechanism behind MAI. In this paper, MAI is achieved through
-
Evaluation of fuel spray ignition delay behavior using a two-stage Lagrangian model Combust. Flame (IF 4.4) Pub Date : 2024-04-18 Yu Wang, Hesheng Bao, Bart Somers, Noud Maes
In this study, a two-stage Lagrangian (TSL) model is used to investigate the ignition process of a fuel spray under engine-like conditions. The existing two-reactor TSL model developed for quasi-steady flames is improved to simulate the ignition process of a fuel spray at engine-like conditions, by inserting a well-validated entrainment model for the liquid fuel spray. The ignition delays of n-dodecane
-
Preparation and reactive performances of Al/Co3O4/CoF2 metastable intermolecular composites Combust. Flame (IF 4.4) Pub Date : 2024-04-17 Yuxiang Li, Kejuan Meng, Momang Tian, Lei Zhang, Xiaoxia Ma, Kaili Zhang
Metastable intermolecular composites (MICs) typically use Al as fuel and transition metal oxides as oxidizers, while their reactivities are hindered by the inert AlO passivation layer on the surface of Al particles. Recently, transition metal fluorides have emerged as novel fluorine-containing oxidizers for promoting the reactivity of metal fuels through interfacial fluorination of oxide layer. In
-
A new index for the comparative evaluation of combustion local low-dimensional manifolds Combust. Flame (IF 4.4) Pub Date : 2024-04-16 Matteo Savarese, Ki Sung Jung, Himanshu Dave, Jacqueline H. Chen, Alessandro Parente
As data-intensive techniques proliferate across many scientific disciplines, new criteria for more objective interpretation and evaluation are required to reconcile data-driven results with understanding of the underlying physics. Many unsupervised tools are used by researchers in the framework of combustion science to simplify models, speed up calculations, and discover hidden patterns in data. Heuristic
-
Kinetical driving force analysis of unstable combustion behavior in ammonia/hydrogen blending system Combust. Flame (IF 4.4) Pub Date : 2024-04-13 Mengze Ai, Shengyao Liang, Lin Ji, Dan Zhao
-
Initiation process of non-premixed continuous rotating detonation wave through Schlieren visualization Combust. Flame (IF 4.4) Pub Date : 2024-04-11 Weijie Fan, Haoyang Peng, Shijie Liu, Mingbo Sun, Xueqiang Yuan, Hailong Zhang, Weidong Liu
High-speed schlieren visualization on the initiation process of non-premixed air and hydrogen continuous rotating detonation (CRD) is carried out in a well-designed rounded-rectangle hollow combustor in this study. The CRD initiation processes of pre-detonator ignition and spark plug ignition are comprehensively revealed by synchronous high-speed schlieren images and high-frequency dynamic pressure
-
Spatiotemporally resolved surface temperature measurement of aluminum ignition and combustion in steam and oxygenated environments Combust. Flame (IF 4.4) Pub Date : 2024-04-09 Zhiyong Wu, Can Ruan, Mehdi Stiti, Shijie Xu, Xue-Song Bai, Edouard Berrocal, Marcus Aldén, Zhongshan Li
We report micrometric imaging measurements of the ignition of micron-sized aluminum (Al) wires and the consequent combustion processes of single micron-sized Al droplets in hot steam and steam with oxygen. The specially designed flames were anchored on a modified burner where a small central H/O diffusion flame in the center jet provided a hot flow (>2330 K) for Al ignition, and the diffusion flame
-
Combustion Structure of a Cylindrical Rotating Detonation Engine with Liquid Ethanol and Nitrous Oxide Combust. Flame (IF 4.4) Pub Date : 2024-04-08 Tomoki Sato, Kotaro Nakata, Kazuki Ishihara, Noboru Itouyama, Ken Matsuoka, Jiro Kasahara, Akira Kawasaki, Daisuke Nakata, Hikaru Eguchi, Masaharu Uchiumi, Akiko Matsuo, Ikkoh Funaki
Liquid propellants are commonly used in rocket engines due to their high energy density. In this study, we focused on the use of liquid ethanol and liquid nitrous oxide as propellants in a cylindrical rotating detonation engine (RDE) for practical applications, and examined the effects of various conditions on the bipropellant RDE performance. We varied the vapor quality of nitrous oxide in a mixture
-
Ab initio kinetics for H-atom abstraction from C1–C5 hydrocarbon and oxygenated species by CH3Ȯ radicals Combust. Flame (IF 4.4) Pub Date : 2024-04-08 Xuan Ren, Xin Bai, Mengmeng Jia, Shuyuan Liu, Yu Han, Ruoyue Tang, Song Cheng, Chong-Wen Zhou, Henry J. Curran, Yang Li
Hydrogen atom abstraction by methoxy (CHȮ) radicals plays an important role in gasoline/ethanol combustion chemistry. Detailed kinetic reactions for H-atom abstraction by CHȮ radicals from short carbon chain species, including alkanes, alkenes (including vinylic, allylic and diene), alkynes, ethers, ketones, and aldehydes is systematically studied in this work. The M06–2X/6–311++g(d,p) level of theory
-
Combustion performance of aluminum modified boron nanoparticles coated with silane coupling agent Combust. Flame (IF 4.4) Pub Date : 2024-04-05 Tianyu Yang, Xiaoyan Qian, Jinyu Dai, Jun Liu, Jiuyu Chen, Jiaxin Wang, Minggao Xu, Yunlan Sun, Baozhong Zhu
Boron (B) powder, with its high mass and volumetric heat values, makes it highly promising in the field of energetic materials. However, the oxide layer on the B surface is the most significant barrier to realizing its full potential as a fuel. How to eliminate or disrupt the oxide layer is currently an urgent problem that needs to be addressed. This study proposes an approach to enhance the combustion
-
Study on the combustion characteristics of NH3 and the inhibition characteristics of R134a on NH3 Combust. Flame (IF 4.4) Pub Date : 2024-04-04 Yongjie Shi, Rui Zhai, Yuan Zhuang, Xiangnong Liu, Siwei Tan, Shun Meng
NH has been considered as an alternative to hydrofluorocarbon (HFC) refrigerants due to its environmentally friendly properties, while it is flammable. Therefore, it is necessary to investigate the flammability of NH (R717) and find its matching flame retardant to broaden its application. In this paper, the combustion behaviors of R717 and the inhibition characteristics of flame retardant R134a on
-
Investigation of thermodynamic state evolution, phase transition and mixing of the hydrocarbon droplet in convective supercritical environments Combust. Flame (IF 4.4) Pub Date : 2024-04-04 Yaquan Ai, Han Wu, Timothy Lee, Decan Zhu, Chia-fon Lee, Xiangrong Li
Liquid alkane droplets transit to supercritical fluids under supercritical conditions. However, the subsequent thermodynamic state evolution, phase transition, and mixing in this case, which directly influences combustion in actual diesel engines, need further investigation. We studied the thermodynamic state evolution, phase transition, and mixing of n-heptane droplets in supercritical laminar nitrogen
-
Edge-flames in circular channels: Multiplicity of steady-state axisymmetric solutions Combust. Flame (IF 4.4) Pub Date : 2024-04-04 Vadim N. Kurdyumov, Carmen Jiménez
A numerical study of the combustion process occurring after separate injection of fuel and oxidizer through an end-wall porous plug into a semi-infinite circular channel is presented. The fuel flow is injected into the center of the channel, surrounded by the oxidizer flow in an axisymmetric manner. It is assumed that the channel walls and the porous plug are kept at constant (cold) temperature. The
-
Pathological detonation in H[formula omitted]-Cl[formula omitted] mixtures: Uncertainty quantification and thermal non-equilibrium effects Combust. Flame (IF 4.4) Pub Date : 2024-04-04 Zituo Chen, Zifeng Weng, Xiangrong Huang, João Vargas, Rémy Mével
Pathological detonations are detonations with a propagation velocity higher than the classical Chapman–Jouguet velocity and which depends on the wave structure. Such a behavior has been experimentally observed in low-pressure hydrogen-chlorine mixtures and important discrepancies were reported between the experimental and the theoretical velocities. Using the steady planar detonation model, along with
-
Particle-resolved hyperspectral pyrometry of metal particles Combust. Flame (IF 4.4) Pub Date : 2024-04-01 J. Hameete, M.S. Abdallah, L.C. Thijs, T.A.M. Homan, X.C. Mi, N.J. Dam, L.P.H. de Goey
We present temperature histories of individual combusting metal particles using hyperspectral pyrometry. This method gives an increase in accuracy over traditionally used two- or three-color pyrometry, while maintaining temporal and spatial resolution. Temperatures can be determined between 1800 to K with a precision of typically 1%. It is shown that the maximum temperature of the burning iron particles
-
Low temperature oxidation chemistry of n-butylbenzene in n-decane/n-butylbenzene mixture: Product characterization and kinetic modeling study Combust. Flame (IF 4.4) Pub Date : 2024-03-29 Wenhao Yuan, Jijun Guo, Zaili Xiong, Yuwen Deng, Jigang Gao, Meirong Zeng, Jiuzhong Yang, Zhongyue Zhou, Fei Qi
-Alkanes and aromatics are two essential components in transportation fuels and have distinct oxidation reactivities. Due to products with different chemical functionalities generated in oxidation of -alkanes and aromatics, the interaction kinetics may significantly affect the overall reactivity as well as product distributions. This work investigated the oxidation chemistry of the mixture of -decane
-
Formation of bubbles and microexplosions in burning boron agglomerates Combust. Flame (IF 4.4) Pub Date : 2024-03-27 Lian Duan, Zhixun Xia, Yunchao Feng, Binbin Chen, Jiarui Zhang, Likun Ma, Jianxin Hu
Combining laser ignition tests with quenched particle cross-sectional analyses, this study explores the formation of bubbles and microexplosions in burning boron agglomerates, and discusses the plausible mechanisms behind the microexplosion (expansion–rupture) phenomenon. High-resolution images reveal that these phenomena are caused by bubble nucleation and growth within the molten droplet. Based on
-
Investigation of multi-scale flow structures and combustion characteristics in a cavity-enhanced circular scramjet Combust. Flame (IF 4.4) Pub Date : 2024-03-27 Tao Tang, Zhenguo Wang, Jiangfei Yu, Yuhui Huang, Mingbo Sun, Hongbo Wang, Guoyan Zhao, Yixin Yang, Dapeng Xiong
This study delves into the investigation of multi-scale flow structures and combustion characteristics in a cavity-enhanced circular scramjet operating under a Mach-4.5 freestream flow condition with a total temperature of 2200 K and a total pressure of 164 kPa. To achieve this, a hybrid large-eddy/Reynolds-averaged Navier-Stokes method, coupled with a pressure-corrected Flamelet/Progress Variable
-
Nonlinear deflection tomography of inhomogeneous flame temperature and concentration based on topology evolution with prior smoothing Combust. Flame (IF 4.4) Pub Date : 2024-03-27 Zhi-Tian Niu, Hong Qi, Si Zheng, Ya-Tao Ren, Ming-Jian He, Fei Wang, Wen-Jun Sun
Tomographic absorption spectroscopy (TAS) is a promising temperature and concentration monitoring technology because it has fewer optical access requirements and species selectivity. However, the inhomogeneous distribution of temperature and species concentration in a practical reaction flow can cause laser deflection, which may affect the imaging quality. Thus, this study aimed to develop a novel
-
Opposed jet burner and Tsuji burner for representative laminar flamelet with differential molecular diffusion for non-premixed combustion modeling Combust. Flame (IF 4.4) Pub Date : 2024-03-26 Tianfang Xie, Haifeng Wang
Modeling differential molecular diffusion in turbulent non-premixed combustion remains challenging for flamelet models. Laminar flamelet is a key building block of flamelet models for turbulent combustion. One significant challenge that has not been adequately addressed is the representativity of laminar flamelet for the characteristics of differential molecular diffusion in turbulent combustion. Laminar
-
Detonation structure in the presence of mixture stratification using reaction-resolved simulations Combust. Flame (IF 4.4) Pub Date : 2024-03-26 Michael Ullman, Supraj Prakash, Shivam Barwey, Venkat Raman
Many investigations of detonation-based combustors have identified reactant mixture inhomogeneity as having a leading-order impact on wave dynamics and combustion efficiency. To examine this phenomenon in a simplified context, an array of two- and three-dimensional channel detonation simulations are conducted in the present work. The reactant mixture consists of stratified fuel and air, wherein the
-
Laser-induced indirect ignition of non-premixed turbulent shear layers Combust. Flame (IF 4.4) Pub Date : 2024-03-26 Jonathan M. Wang, Mario Di Renzo, Gianluca Iaccarino, Hai Wang, Javier Urzay
This study uses direct numerical simulations to investigate the forced ignition of temporally-evolving turbulent subsonic shear layers separating a gaseous stream of methane (CH) and a stagnant gas environment of molecular oxygen (O). Ignition is forced by a thermal-energy source that heats up a small volume of gas during periods of time much shorter than the characteristic acoustic time scale. The
-
Preparation of core-shell structured Al-5Li@HTPB powders with improved stability and combustion performance by using perfluoroalkylsilane as a surfactant Combust. Flame (IF 4.4) Pub Date : 2024-03-26 Jiabao Zhu, Shuo Wang, Weiqiang Xiong, Jun Wang, Xiaodong Li, Meishuai Zou
Aluminum-lithium alloy powder exhibits better thermal properties and combustion performances than aluminum, thus showing promising applications in the field of energetic materials such as explosives and propellants. However, the high activity of lithium also raises issues of stability and compatibility with propellant components, deteriorating the powder's overall performance. In this study, a facile
-
On the difficulty of interpreting NO-LIF measurements around 226 nm in confined ammonia flames Combust. Flame (IF 4.4) Pub Date : 2024-03-25 Nour El Baba, Pascale Desgroux, Nathalie Lamoureux
This paper addresses how NH and NO absorption along the laser axis disrupts NO-LIF measurements made around 225 nm in NH/O/N premixed flames confined at low pressure (10 kPa). Measurements were performed in 3 flames (equivalence ratio = 0.87, 1.1 and 1.3) with 24 % N dilution. Together with the LIF measurements, single-pass absorption measurements were obtained in all flames as a function of the height
-
Characteristics of laminar lifted flames of pure ethane in a non-premixed jet under various pressures Combust. Flame (IF 4.4) Pub Date : 2024-03-23 Gyu Jin Hwang, Dong Seok Jeon, Nam Il Kim
Recent studies have discovered that laminar lifted flames (LLFs) can be stabilized within a triangular stabilization regime (TSR), defined by the parameters of normalized lift-off height and Reynolds number. The stabilization mechanism of an LLF could be explained by using an effective Schmidt number over an extended pressure range. In this study, the existence of LLFs of pure ethane was confirmed
-
Laser diagnostics in combustion and beyond dedicated to Prof. Marcus Aldén on his 70th birthday Combust. Flame (IF 4.4) Pub Date : 2024-03-21 Zhongshan Li, Christian Brackmann, Joakim Bood, Mattias Richter, Per-Erik Bengtsson, Katharina Kohse-Höinghaus
-
Application of emission spectroscopy in plasma-assisted NH3/air combustion using nanosecond pulsed discharge Combust. Flame (IF 4.4) Pub Date : 2024-03-21 Jinguo Sun, Yupan Bao, Jonas Ravelid, Sebastian Nilsson, Alexander A. Konnov, Andreas Ehn
This work investigates the effects of atmospheric-pressure nanosecond (ns) pulsed plasma discharges on NH/air flames using optical emission spectroscopy (OES). Firstly, spatially-resolved OES in the 200–800 nm range of NH/air flames with and without discharges are presented to identify the plasma-induced excited species (such as N* and H*). Then, time-resolved OES with ns timescale resolution are achieved
-
Evaluation of the thermo-acoustic instability frequency and growth rate via input reflection coefficient measurement for central heating equipment Combust. Flame (IF 4.4) Pub Date : 2024-03-20 Mohammad Kojourimanesh, Viktor Kornilov, Ines Lopez Arteaga, Philip de Goey
-
Freestream and shear layer effects in bluff-body-stabilized turbulent premixed flames Combust. Flame (IF 4.4) Pub Date : 2024-03-20 Christopher A. Fugger, R.A. Forlines, Brendan T. Paxton, Andrew W. Caswell, Brent A. Rankin
The effects of low and high approach flow turbulence levels on a large-scale, confined, premixed bluff-body-stabilized flame are experimentally characterized. The flame and flow are imaged using simultaneous 10-kHz-rate formaldehyde (CHO) planar laser-induced fluorescence (PLIF), hydroxyl (OH) PLIF, particle image velocimetry (PIV), and OH* chemiluminescence. Elevated approach flow turbulence intensities
-
Dynamic laser ignition characteristics of solid fuel and oxygen for hybrid rocket system Combust. Flame (IF 4.4) Pub Date : 2024-03-19 Hanqing Xia, Ningfei Wang, Jiantao Pang, Yi Wu
The transient laser ignition process in a slab burner that is similar to hybrid rocket motors is investigated in this study. The coupling characteristics between solid fuel properties, pyrolysis rate, and laser power were analysed. The results show that the laser ignition process can be divided into four stages: preheating, pyrolysis, ignition, and combustion, with the preheating and pyrolysis stages
-
Dual-range emission spectroscopy for temperature measurement of laminar aluminum dust flames Combust. Flame (IF 4.4) Pub Date : 2024-03-19 Tao Yu, Kartik Mangalvedhe, Mathieu Francoeur, Jeffrey M. Bergthorson
Understanding the temperature fields/profiles in aluminum dust flames is critical to the design of aluminum-based sustainable fuels and the development of aluminum combustion simulation tools. Although emission spectroscopy has been applied in aluminum flames, the signals in most works were integrated along the recording path and over the whole flame and, therefore, the measurements could not provide
-
Novel graphene iron organic nanocomposites for enhancing combustion and safety properties of AP-HTPB propellant Combust. Flame (IF 4.4) Pub Date : 2024-03-18 Ming Zhang, Fengqi Zhao, Jiankan Zhang, Ying Wang, Xueli Chen, Ting An, Zhao Qin, Haixia Hao
Graphene iron tannate and graphene iron gallate nanocomposites (G-D-Fe and G-M-Fe) were designed, synthesized and characterized to deal with the performance requirement of AP-HTPB propellent. Effects of the G-D-Fe and G-M-Fe on the thermal decomposition of AP, laser ignition, combustion and safety characteristics of AP-HTPB propellant were explored. By taking Catocene as the benchmark (156.80 mJ),
-
Combustion and plume-plasma characteristics of cesium-based solid propellant Combust. Flame (IF 4.4) Pub Date : 2024-03-16 Zhiwen Wang, Hui Wang, Lian Li, Qianyi Zhang, Feng Li, Ruiqi Shen, Yinghua Ye, Wei Zhang
The high-temperature plume of solid propellant has spawned considerable amount of highly ionized plasma, which can be used to increase the specific impulse of propellant with the external physical field, as well as serve as the charged particles for the (MHD) generator on the thruster. Unfortunately, the deficiency of workable deal to promote the electrical performance of the plume hinders the development
-
Influence of slit asymmetry on blow-off and flashback in methane/hydrogen laminar premixed burners Combust. Flame (IF 4.4) Pub Date : 2024-03-16 H. Pers, P.A. Masset, E. Flores-Montoya, L. Selle, T. Schuller
One way to decarbonize the heat production sector is to gradually replace natural gas with hydrogen. The design of laminar premixed burners capable of operating with both methane and hydrogen is however challenging as these fuels have drastically different burning properties, which narrows the operating range. While methane flames face limitations in stabilization due to blow-off at high power, hydrogen
-
A detailed kinetic submechanism for OH[formula omitted] chemiluminescence in hydrogen combustion revisited. Part 2 Combust. Flame (IF 4.4) Pub Date : 2024-03-15 Alexander S. Sharipov, Boris I. Loukhovitski, Alexey V. Pelevkin, Mayya R. Korshunova
In this series of two papers, we present a novel physically sound kinetic submechanism aimed at modeling the formation and decay of chemiluminescent (electronically excited) OH molecules in the ignition and combustion of hydrogen and hydrogen-based mixtures over a wide range of temperatures and pressures. The present Part describes the construction of this detailed reaction submechanism based on the
-
Near-limit detonation in long spiral tube: An improved experimental methodology and frequency analysis Combust. Flame (IF 4.4) Pub Date : 2024-03-15 Zhaoyuan Huang, Zihang Ni, Zongtai Li, Zifeng Weng, Damir Valiev, Rémy Mével
In the present work, near-limit detonations in near stoichiometric propane-oxygen mixtures were investigated using a long spiral tube facility. Compared to previous studies, our improvements in the tube length, framing rate and resolution, image processing methods for distortion correction and detonation front detection, allow for a significant increase of the amount and quality of data obtained. As
-
Impact of multi-component description of hydrophilic fuel droplets in propagating spray flames Combust. Flame (IF 4.4) Pub Date : 2024-03-15 Fernando Luiz Sacomano Filho, Luís Eduardo de Albuquerque Paixão e Freire de Carvalho, Artur Carvalho Santos, Aymeric Vié, Jeroen Adrianus van Oijen
The need for an accurate description of the fuel composition is emerging in recently published studies on the interaction of droplets and flames. In this context, hydrophilic fuels are of particular importance, since they are expected to interact with the water formed during combustion reactions. The impact of such interactions onto the reaction process is still not explored enough. This work aims
-
Combustion enhancement of boron-containing fuel-rich mixture by steam reforming in a supersonic flow Combust. Flame (IF 4.4) Pub Date : 2024-03-14 Chaolong Li, Weiguang Cai, Zhixun Xia, Likun Ma, Shu Zheng, Binbin Chen, Yunchao Feng, Jiarui Zhang
In this paper, a novel experimental investigation was conducted to enhance the combustion of boron-containing fuel-rich mixture by steam reforming in a supersonic flow. The ground direct-connected experiments were designed to simulate a flight condition at Mach number 5.9 and an altitude of 25 km. The operating characteristics and performance evaluation of the scramjet combustor were analyzed and discussed
-
On the structure and dynamics of strong and weak eigenvalue detonation in condensed explosives Combust. Flame (IF 4.4) Pub Date : 2024-03-14 Vincent R. Schuetz, D. Scott Stewart
An eigenvalue detonation, also known as a pathological detonation, is a detonation with incomplete reaction at a point in the detonation reaction zone, that is sonic relative to the leading shock. Aluminized explosives are made by combining a molecular explosive with aluminum and other additives. During detonation, the molecular explosive’s first exothermic decomposition generates products that react
-
Experimental study of ignition and combustion characteristics assisted by laser-induced plasma during oxy-coal atmosphere by optical emission spectroscopy Combust. Flame (IF 4.4) Pub Date : 2024-03-14 Wenkun Zhu, Mengfan Yuan, Xiaohui Li, Long Gao, Yonghong Yan, Jiangbo Peng, Zhuozhi Wang, Wenbei Liu, Rui Sun
This investigation aims to understand the enhancement characteristics of plasma-assisted combustion in oxy-coal combustion. A 1064 nm Nd:YAG laser was added into a laminar flow reactor to produce laser-induced plasmas (LIPs). The high-speed visualization of the coal flame was used to reveal combustion's progress and evolution following laser-induced breakdown. To the best of our knowledge, this is
-
Phenomenological regression rate model in axial injection end-burning hybrid rocket motor using different oxidizers Combust. Flame (IF 4.4) Pub Date : 2024-03-14 Giuseppe Gallo, Mai Fukada, Sho Suzuki, Harunori Nagata
Compared with conventional configurations, axial-injection end-burning hybrid rocket motors work with multiport fuel grains, which mainly burn in the axial direction. The consumption rate is controlled by the several flames developed at the end of each port. Although many studies of performance and flame stability have been carried out in the past, a phenomenological model of the axial regression rate
-
Super adiabatic combustion of H2/Air and H2/N2O mixtures Combust. Flame (IF 4.4) Pub Date : 2024-03-14 Jennifer L. Schurr, Atmadeep Bhattacharya, Alexander A. Konnov, Ossi Kaario
While the impact of H chemistry on super adiabatic flame temperature (SAFT) for hydrocarbons is well understood, super adiabaticity for premixed H combustion has not been previously reported. In the present work, for the first time, premixed H/air and H/NO combustion in 0D and 1D context have been analysed to show that the instantaneous (0D) or local (1D) temperature exceeds the equilibrium temperature
-
A detailed kinetic submechanism for OH[formula omitted] chemiluminescence in hydrogen combustion revisited. Part 1 Combust. Flame (IF 4.4) Pub Date : 2024-03-13 Alexander S. Sharipov, Boris I. Loukhovitski, Alexey V. Pelevkin, Mayya R. Korshunova
In this series of two papers, we present a novel physically sound kinetic submechanism aimed at modeling the formation and decay of chemiluminescent (electronically excited) OH molecules in the ignition and combustion of hydrogen and hydrogen-based mixtures over a wide range of thermodynamic parameters and mixture compositions. The present part of this series describes the preparatory stages of the