Proceedings of the Combustion Institute最新文献

{"title":"Shock-tube and modeling study of trichloromethane pyrolysis and trichloromethane/methane oxidation using a HCl laser absorption diagnostic","authors":"Claire M. Grégoire,&nbsp;Eric L. Petersen","doi":"10.1016/j.proci.2025.105823","DOIUrl":"10.1016/j.proci.2025.105823","url":null,"abstract":"<div><div>Chlorinated hydrocarbon burning characteristics when involved in incineration processes and when formed during rocket propellant combustion are not well understood, and evaluations of their chemical kinetics mechanisms at high temperatures are limited by the scarce experimental measurements. The pyrolysis of trichloromethane (CHCl₃) and the oxidation of CHCl₃/methane (CH₄) at ϕ = 1.0, both highly diluted in 99.5 % Ar, were investigated behind reflected shock waves near atmospheric pressure using a new H³⁵Cl spectroscopic laser diagnostic. The ability to monitor the isotope H³⁵Cl was possible using a laser source centered at 3045.06 cm^-1 aiming at the H³⁵Cl R(8) transition line in the fundamental band of the spectrum. A large span of temperatures was investigated, i.e. ranging from 1068 to 1444 K for CHCl₃ pyrolysis, where the most sensitive reaction CHCl₃ <span><math><mrow><mo>⇄</mo><mspace></mspace></mrow></math></span> CCl₂ + HCl (R1) produces the H³⁵Cl in correlation to the natural abundance proportions, namely <span><math><mrow><mrow><mo>[</mo><mrow><msup><mrow><mi>H</mi></mrow><mn>35</mn></msup><mi>C</mi><mi>l</mi></mrow><mo>]</mo></mrow><mo>≈</mo><mn>3</mn><mspace></mspace><mo>×</mo><mrow><mo>[</mo><mrow><msup><mrow><mi>H</mi></mrow><mn>37</mn></msup><mi>C</mi><mi>l</mi></mrow><mo>]</mo></mrow></mrow></math></span>. Similarly, the oxidation of CHCl₃/CH₄ was recorded at temperatures between 1471 and 2094 K, and the interactions of the active Cl radicals <img>provided by the dichlorocarbene (CCl₂) via the reaction 2CCl₂ <span><math><mrow><mo>⇄</mo><mspace></mspace></mrow></math></span> C₂Cl₃ + Cl (R2)<img> with CH₄ are observed and driven by the reaction CH₄ + Cl <span><math><mrow><mo>⇄</mo><mspace></mspace></mrow></math></span> CH₃ + HCl (R3). Numerical predictions from available detailed kinetics mechanisms for chlorinated hydrocarbons in the literature are compared against this comprehensive set of experimental results, and significant discrepancies are observed. Routes for improvements toward predicting this major intermediate species, i.e. HCl, are suggested. By strengthening the fundamental database for the combustion kinetics of chlorinated hydrocarbons, strategies to reduce the dominant release of extremely toxic chemicals could be discovered.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105823"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145018806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soot primary particle radial profiles in laminar diffusion flames for Jet A-1/SAF fuels: A SAXS study","authors":"M. Littin ,&nbsp;M. Mazur ,&nbsp;G. Lefevre ,&nbsp;M. Sztucki ,&nbsp;A. Fuentes ,&nbsp;J. Yon","doi":"10.1016/j.proci.2025.105852","DOIUrl":"10.1016/j.proci.2025.105852","url":null,"abstract":"<div><div>Sustainable aviation fuels (SAF) are designed to progressively replace conventional Jet A-1 fossil fuel, with documented lower soot emissions. However, detailed understanding of how SAF blending affects soot formation mechanisms remains limited. The present study employs Small-Angle X-ray Scattering (SAXS) to characterize soot primary spheres in laminar diffusion flames burning ethylene and Jet A-1/HEFA-SPK blends and to analyze their spatial distribution. Using a recently developed Spline-Based Abel Transform (SAT) method for signal deconvolution and an improved SAXS model, spatially-resolved radial profiles of primary particle size distributions are determined across the flame. The analysis reveals distinct differences between pure Jet A-1 and HEFA-SPK-blended flames: Jet A-1 produces larger primary particles (maximum <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>p</mi><mo>,</mo><mi>g</mi><mi>e</mi><mi>o</mi></mrow></msub></math></span> of <span><math><mrow><mn>27</mn><mo>±</mo><mn>1</mn><mo>.</mo><mn>5</mn><mspace></mspace><mi>nm</mi></mrow></math></span>) with sharp transitions between growth and oxidation regions, while HEFA-SPK blends show smaller particles (maximum <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>p</mi><mo>,</mo><mi>g</mi><mi>e</mi><mi>o</mi></mrow></msub></math></span> of <span><math><mrow><mn>16</mn><mo>±</mo><mn>2</mn><mo>.</mo><mn>5</mn><mspace></mspace><mi>nm</mi></mrow></math></span>) with more gradual transitions. This suggests that HEFA-SPK addition fundamentally alters soot formation dynamics rather than simply reducing particle size. The Porod invariant, which is proportional to the soot volume fraction, shows systematic decreases in soot volume fraction with increasing HEFA-SPK content while maintaining similar particle size distribution patterns. This work presents the first comprehensive dataset of spatially-resolved primary particle characteristics in aviation fuel flames, offering valuable insights for soot formation modeling and clean combustion technology development.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of dispersion length on volume-averaged simulations of ammonia/air combustion in porous media burners","authors":"Rishabh Puri ,&nbsp;Daniel Kretzler ,&nbsp;Benjamin Bock-Seefeld ,&nbsp;Björn Stelzner ,&nbsp;Nora Brachhold ,&nbsp;Jana Hubálková ,&nbsp;Dimosthenis Trimis ,&nbsp;Christos Aneziris ,&nbsp;Oliver T. Stein ,&nbsp;Thorsten Zirwes","doi":"10.1016/j.proci.2025.105856","DOIUrl":"10.1016/j.proci.2025.105856","url":null,"abstract":"<div><div>Ammonia is a carbon-free alternative to fossil fuels and can potentially be integrated in the existing energy infrastructure. However, due to poor flame stability and high pollutant emissions, clean combustion of ammonia is a current topic of research. Porous media burners have shown potential to improve the combustion characteristics of ammonia and ammonia blends, which are otherwise difficult to stabilise in conventional burners. Combustion in porous media can be investigated in great detail by performing three-dimensional direct pore-level simulations (3D-DPLS). However, 3D-DPLS with complex ammonia chemistry are computationally expensive. Volume-averaged simulations (VAS) are an efficient alternative for numerical investigations of porous burners. In this work, a comprehensive VAS framework is proposed for 1D, 2D, and 3D transient VAS, taking variable porosity, detailed chemistry and diffusion into account. The numerical framework allows for on-the-fly definitions of constitutive models for effective properties, e.g. tortuosity, dispersion and permeability. After successful validation with other VAS cases from literature, the new code is used to analyse an experimentally investigated novel porous ammonia burner. The analysis is performed to study the effect of the characteristic dispersion length of the solid matrix, which is hard to measure for practical geometries, on pollutant formation and energy balance. All other effective properties are obtained directly from <span><math><mi>μ</mi></math></span>-CT scans. Both fuel-lean and fuel-rich conditions of ammonia/air combustion in porous media are investigated. As the characteristic dispersion length increases, local peak temperatures decrease. This significantly affects the predicted <figure><img></figure> and NH₃ emissions. Higher dispersion lengths lead to a broadening of the flame zone that can lead to larger lift-off heights from the burner inlet and merging of neighbouring flames Therefore, reliable estimates of characteristic dispersion lengths are required to achieve good predictions from VAS.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105856"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the thermal decomposition reactions of HMX using online photoionization mass spectrometry","authors":"Hairong Ren ,&nbsp;Guangda Luo ,&nbsp;Xintong Xiao ,&nbsp;Yuzhou Huang ,&nbsp;Feng Zhang ,&nbsp;Long Zhao ,&nbsp;Zhongyue Zhou ,&nbsp;Xinghui Liu ,&nbsp;Xiang Guo ,&nbsp;Fei Qi","doi":"10.1016/j.proci.2025.105849","DOIUrl":"10.1016/j.proci.2025.105849","url":null,"abstract":"<div><div>1,3,5,7-Tetranitro-1,3,5,7-tetrazoctane (HMX) is a high-performance energetic material widely used in solid propellants. Understanding its thermal decomposition process is crucial for improving the combustion efficiency of these propellants. However, the rapid pyrolysis process and the complexity of the resulting products pose significant challenges to elucidating its decomposition mechanism. To investigate the pyrolysis process of HMX, online photoionization time-of-flight mass spectrometry (PI-TOFMS) and atmospheric photoionization ultra-high resolution mass spectrometry (APPI-HRMS) were employed to characterize the thermal decomposition products at atmospheric pressure (10⁵ Pa) and low pressure (10⁻³ Pa), respectively. Leveraging the soft ionization capability of photoionization, several key pyrolysis products of HMX were identified, such as HONO-elimination products, NO₂-elimination products, fragments from ring opening, and products from ring contraction and growth. The experimental results reveal that the thermal decomposition process of HMX involves several possible channels: (i) HONO-elimination &amp; N<img>NO₂ bond cleavage; (ii) cleavage of HMX along the symmetry axis into two INT148; (iii) ring contraction; (iv) ring scission; (v)growth of nitrogen-containing polycyclic aromatic hydrocarbons (NPAHs).</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105849"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-dimensional structure and burning speed of turbulent premixed H2–air and H2/CH4–air Bunsen flames using high-speed tomographic imaging","authors":"Tao Li ,&nbsp;Haowen Chen ,&nbsp;Simone Hochgreb","doi":"10.1016/j.proci.2025.105830","DOIUrl":"10.1016/j.proci.2025.105830","url":null,"abstract":"<div><div>The deployment of lean premixed hydrogen combustion for carbon-free power generation necessitates a better understanding of flame structure and burning speed, where volumetric information plays a crucial role. This work presents a novel tomographic imaging approach to reconstruct the volumetric Mie scattering signal distribution from seeded droplets in Bunsen flames, enabling detailed measurements of 3D flame surface topology, surface area, and turbulent flame speed. A series of lean turbulent premixed H₂-air and H₂/CH₄-air flames from the Cambridge piloted Bunsen burner were investigated, systematically varying the equivalence ratio, Lewis number, and Karlovitz number. A high-speed tomographic imaging system, consisting of eight simultaneous views was employed to capture volumetrically illuminated Mie scattering within an approximately 20(x)<span><math><mo>×</mo></math></span>40(y)<span><math><mo>×</mo></math></span>12(z)<!--> <!-->mm<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span> probe volume. The reconstructed 3D signals using the SMART algorithm enables reliable flame front detection and surface triangulation. Based on this reconstruction, flame structures were analyzed by computing mean and Gaussian curvatures, as well as principal curvatures. Results reveal that hydrodynamic instabilities (HDI) induce regular surface oscillations near the Burner exist, while thermodiffusive instabilities (TDI) enhance surface fluctuations near the flame tip. The HDI is found to be more prominent at low-<span><math><mrow><mi>K</mi><mi>a</mi></mrow></math></span> and near-unity <span><math><mrow><mi>L</mi><mi>e</mi></mrow></math></span> conditions, whereas TDI dominates in moderate-<span><math><mrow><mi>K</mi><mi>a</mi></mrow></math></span> and sub-unity <span><math><mrow><mi>L</mi><mi>e</mi></mrow></math></span> flames, leading to increased surface wrinkling. Additionally, both instantaneous flame surfaces and surfaces based on the mean progress variable were examined and used to derive global and local flame speeds. It was observed that the normalized turbulent flame speed ratio, <span><math><mrow><msub><mrow><mi>S</mi></mrow><mrow><mtext>T</mtext></mrow></msub><mo>/</mo><msub><mrow><mi>S</mi></mrow><mrow><mtext>L</mtext></mrow></msub></mrow></math></span>, can be effectively scaled with turbulence intensity and Lewis number. However, the accuracy of the surface area calculation significantly affects the precise determination of <span><math><mrow><msub><mrow><mi>S</mi></mrow><mrow><mtext>T</mtext></mrow></msub><mo>/</mo><msub><mrow><mi>S</mi></mrow><mrow><mtext>L</mtext></mrow></msub></mrow></math></span>. Overall, the tomographic laser diagnostic technique demonstrated in this study provides valuable insights into the flame structures and burning characteristics of lean turbulent premixed H₂-air and H₂/CH₄-air combustion.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105830"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical analysis of the stability of iron dust Bunsen flames","authors":"T. Hazenberg,&nbsp;D. Braig,&nbsp;J. Mich,&nbsp;A. Scholtissek,&nbsp;C. Hasse","doi":"10.1016/j.proci.2025.105861","DOIUrl":"10.1016/j.proci.2025.105861","url":null,"abstract":"<div><div>This article presents numerical simulations of the response of an iron dust Bunsen flame to abrupt changes in particle seeding. A validated numerical model is employed to investigate the effect of particle seeding fluctuations on flame stability. Simulations are conducted for the Bunsen setup in both right-side-up and upside-down configurations. No significant differences in flame response are identified in flame stability between the right-side-up and upside-down configurations. The flame response does not show signs of flame wrinkling or activation of other intrinsic instabilities. As a result, the flame is surprisingly robust to abrupt changes in particle loading. We hypothesize that the robustness of the flame to imposed fluctuations is due to the lack of a feedback mechanism between the burned temperature and the heat release rate. This mechanism is present in conventional, chemistry-driven, gaseous flames. However, such a mechanism is absent in iron dust flames because the combustion of individual iron particles is limited by oxygen diffusion, which is insensitive to temperature. The high robustness of the flame appears to contradict experimental observations, where flames are found to be highly unstable, which raises questions about the mechanism underlying the instability of experimental flames.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105861"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical characterization of stratified weakly turbulent hydrogen flames","authors":"Raphael Strickling,&nbsp;Faizan Habib Vance,&nbsp;T. Jeremy P. Karpowski,&nbsp;Christian Hasse,&nbsp;Arne Scholtissek","doi":"10.1016/j.proci.2025.105844","DOIUrl":"10.1016/j.proci.2025.105844","url":null,"abstract":"<div><div>Lean hydrogen combustion offers great potential to reduce greenhouse gas emissions. However, due to its unique combustion characteristics, hydrogen poses significant challenges regarding operational safety of burners and their <figure><img></figure> emissions. To address these challenges, burner designs must be adapted to ensure the safe and efficient combustion of hydrogen. Previous works indicate that a targeted mixture stratification in the radial direction has the potential of reducing the flashback propensity of hydrogen flames anchored at the sharp edge of a burner outlet. However, the homogeneity of the mixture at the burner outlet also has a significant impact on <figure><img></figure> emissions of (partially) premixed hydrogen-air flames. Combining both ideas, two burner designs featuring a <em>radial</em> mixture stratification with varying levels of mixture homogeneity in the <em>angular</em> direction at the burner outlet are presented. These designs are analyzed using LES with adaptive mesh refinement for the flame zone and detailed chemistry to evaluate the flame’s stabilization behavior and <figure><img></figure> emissions in comparison to a reference fully premixed flame. The results of the numerical simulations suggest that the mixture stratification approach is effective for the weakly turbulent flames stabilized on the mesoscale nozzles considered in the present work. Furthermore, the analysis of the <figure><img></figure> emissions provides useful implications to guide future nozzle design and assessment prior to (additive) manufacturing and experimental investigation.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105844"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling collision frequencies and predicting bi-variate agglomerate size distributions for bi-disperse primary particle systems","authors":"Anjul Pandey, Maximilian Karsch, Andreas Kronenburg","doi":"10.1016/j.proci.2024.105706","DOIUrl":"https://doi.org/10.1016/j.proci.2024.105706","url":null,"abstract":"Agglomerate growth and the evolution of the agglomerate size distribution is determined by the collision frequencies between the agglomerates of the different size classes. For size distributions that can be parameterized by the agglomerates size only, expressions for the collision kernels exist and agglomerate growth can be predicted with sufficient accuracy. In the case of systems with polydisperse primary particles such as the agglomeration of soot or of systems with several components such as the flame synthesis of nanoparticles with taylor-made catalytic properties, a bi- or polydisperse size distribution is needed to account for the effects of the different primary particle sizes. In the present paper, collision frequency are obtained from a large series of Langevin dynamics (LD) simulations that are largely “model-free”. Bi-disperse primary particle systems are investigated where the size ratios of the primary particles are varied from unity to a factor of up to six. An analytic expression for an effective collision radius is suggested and accounts for functional dependencies on agglomerate size, composition and fractal dimension. Independent simulations for the evolution of the population balance equation (PBE) for the bi-variate agglomerate size distribution are conducted and assessed by comparison with corresponding Langevin dynamics simulations. The agreement between PBE solution and LD simulation results is generally very good indicating sufficient accuracy in modelling the collision kernel. Additional PBE simulation for mono-variate size distributions notably underpredict collision rates and errors of up to 140% in the total number of agglomerates can be expected by the end of a simulation for the larger size ratios. Errors are small for size ratios of two, but overall, a bi-variate parameterization of the population size distribution is needed to accurately predict agglomerate growth if the size ratio between the primary particles is notably larger than two.","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"21 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental research on radiation blockage of the fuel vapor and flame in pool fires","authors":"Fanliang Ge, Anthony Hamins, Tinting Qiu, Jie Ji","doi":"10.1016/j.proci.2024.105764","DOIUrl":"https://doi.org/10.1016/j.proci.2024.105764","url":null,"abstract":"Pool fires are the most prevalent accidents in the process industry. Revealing the physical mechanism of pool fire has both fundamental and practical applications in process safety and risk analysis. This paper intends to study the radiation blockage phenomenon caused by fuel vapor and flame in pool fires. Combustion and evaporation (non-combustion) experiments under different external radiative heat fluxes have been conducted to differentiate the radiation blockage of the fuel vapor and the flame. Four different sooting fuels including methanol, ethanol, n-heptane and toluene were used in the experiments. The radiation blockage of fuel vapor was determined through evaporation experiments. The radiation blockage of flame and the total radiation blockage of pool fires were investigated by burning experiments. Based on the assumptions of radiation gray for flame radiation and external radiation, the effective radiation blockage was determined. It is found that the effective radiation blockage coefficient of the fuel vapor increases with fuel mass flux first, and then gradually approaches a constant value because the radiation absorption capacity of the fuel vapor tends to saturate with the increase of fuel mass flux. The correlations between the fuel vapor radiation blockage coefficient and fuel mass flux are established based on theoretical analysis and experimental data. Moreover, the flame blockage coefficient decreases with external radiation for methanol, ethanol and n-heptane because the fire expands, causing enhanced radiative heat feedback from the flame. For the heavily sooting fuel, toluene, the flame radiation blockage almost remains constant with external radiation due to high soot concentrations.","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"7 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Micron-sized iron particles as energy carrier: Cycling experiments in a fixed-bed reactor","authors":"Carola Kuhn, Marco Kirn, Steffen Tischer, Olaf Deutschmann","doi":"10.1016/j.proci.2024.105207","DOIUrl":"https://doi.org/10.1016/j.proci.2024.105207","url":null,"abstract":"Iron is a promising energy carrier with the potential to store substantial amounts of energy over extended time periods with minimal losses. For instance, the energy from green hydrogen sources can be used to reduce iron oxides, be stored or transported, and thus be regained by exothermic oxidation of the iron. This work explores the influence of oxygen partial pressure and temperature on the oxidation process in a fixed-bed reactor. Furthermore, the analysis extends to the reduction of oxidized iron particles at varying temperatures. The experimental findings highlight that both oxidation and reduction progress through the fixed-bed reactor as distinct reaction fronts. In the oxidation process, the speed of the reaction front increases with rising oxygen content and temperature, resulting in a higher reaction rate and a correspondingly increased heat release. Conversely, the reaction rate for reduction experiences a notable decrease for 600°C and 700°C. The reprocessability of the iron powder was validated for up to 16 cycles under the optimal reaction conditions established. Furthermore, it was demonstrated that the performance improves with an increasing number of cycles. This improvement is attributed to the formation of pores due to density changes and the subsequent creation of a larger surface area, mitigating the negative effects of sintering and agglomeration.","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"43 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}