Applications in Energy and Combustion Science最新文献

{"title":"Research and development needs in combustion modeling","authors":"Venkateswaran Sankaran","doi":"10.1016/j.jaecs.2024.100307","DOIUrl":"10.1016/j.jaecs.2024.100307","url":null,"abstract":"<div><div>This article provides a perspective on future research and development needs of aerospace propulsion from the vantage point of the Air Force Research Lab (AFRL). Particular applications that inform this perspective include solid and liquid rocket propulsion for booster applications, scramjet propulsion for hypersonic flight and rotating detonation engines for both air and space applications. The R&amp;D needs are expressed in two categories—the first represents foundational research needs informed by specific application challenges, while the second catalogs foundational research needs informed broadly by digital engineering paradigms for future development. The former category concerns traditional research in combustion and energy sciences, while the latter category embraces emerging computational and mathematical research topics. Future progress will be depend upon advancements in both sets of topic areas.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"21 ","pages":"Article 100307"},"PeriodicalIF":5.0,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of chemical kinetic models for simulations of hydrogen detonations by comparison with experimental data","authors":"Vigneshwaran Sankar,&nbsp;Karl P. Chatelain,&nbsp;Deanna A. Lacoste","doi":"10.1016/j.jaecs.2024.100306","DOIUrl":"10.1016/j.jaecs.2024.100306","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Two-dimensional numerical simulations of a weakly unstable detonation mixture &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;H&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;O&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;76&lt;/mn&gt;&lt;mtext&gt;Ar&lt;/mtext&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;20&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mtext&gt;kPa&lt;/mtext&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;295&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mtext&gt;K&lt;/mtext&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; were performed using our validated OpenFOAM solver based on &lt;span&gt;reacting&lt;/span&gt;-&lt;span&gt;PimpleCentralFoam&lt;/span&gt;. This study compared the detonation dynamics obtained with four chemical models, namely Hong 2011, Burke 2012, Mével 2014, and FFCM-2 with recently obtained experimental results. The experimental–numerical comparisons were performed in threefold: (i) quantitative comparisons of the cell sizes (&lt;span&gt;&lt;math&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;) and their distributions (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;); (ii) qualitative comparisons of the detonation structure based on simultaneous planar laser-induced fluorescence of both nitric oxide (NO-PLIF) and OH radical (OH-PLIF); (iii) qualitative and quantitative comparisons of the detonation dynamics based on combined Rayleigh scattering and NO-PLIF measurements. The simulations conducted with Hong 2011’s, Burke 2012’s, and FFCM-2’s models satisfactorily reproduced the average cell size (within 10%), while it was 1.5 times smaller with Mével 2014’s model. The opposite trends were observed in cell size distributions (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) with satisfactory predictions from Mével 2014’s model (within 25%) and almost no cell size variations (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; &lt;!--&gt; &lt;span&gt;&lt;math&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt; &lt;!--&gt; &lt;!--&gt;0.1) for the other models. By comparing the simultaneous NO- and OH-PLIF imaging, the simulations conducted with FFCM-2’s and Mével 2014’s models qualitatively reproduced the reaction zone structure, while more discrepancies were obtained with Hong 2011’s and Burke 2012’s models. Quantitatively, simulations conducted with FFCM-2’s and Mével 2014’s models presented the lowest discrepancy (below two-fold) at reproducing the induction zone dynamics along the cellular cycle, while large discrepancies (approximately three-fold) were observed with Hong 2011’s and Burke 2012’s models. Chemical timescale analyses evidenced the relation between the faster reaction timescales of Mével 2014’s model and the ability to reproduce the experimental variability on both &lt;span&gt;&lt;math&gt;&lt;mi&gt;λ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Δ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;. These detailed comparisons emphasized the importance of the chemical model selection and the need for combined experimental measurements to both validate c","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"21 ","pages":"Article 100306"},"PeriodicalIF":5.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and numerical study of soot formation in hydrocarbon sprays under high-pressure fuel pyrolysis conditions","authors":"Hyung Sub Sim ,&nbsp;Emre Cenker ,&nbsp;Eungyo Choi ,&nbsp;Kevin Wan ,&nbsp;Scott A. Skeen ,&nbsp;Julien Manin","doi":"10.1016/j.jaecs.2024.100310","DOIUrl":"10.1016/j.jaecs.2024.100310","url":null,"abstract":"<div><div>This study combined high-speed optical diagnostics and numerical simulation to investigate soot formation in n-dodecane sprays under conditions characterized by fuel pyrolysis and low oxygen concentrations. Numerical models were employed to predict the evolution of polycyclic aromatic hydrocarbons (PAHs), while the experiments focused on soot formation. A 186-µm single-hole orifice nominal diameter injector was employed to inject well-controlled fuel sprays into a constant-volume chamber operating at 76 bar. We use a short injection duration of approximately 100 µs to maximize the residence time of the fuel, with variations in the ambient gas temperature within the range of 1,400 to 1,700 K, and the oxygen concentration was ranged from 0 to 5 %. Additionally, we conducted closed-homogeneous-reactor and two-stage Lagrangian simulations with various kinetic mechanisms to predict PAH formation and compared the results with experimental data. The experimental results revealed that variations in the ambient temperature and oxygen percentage significantly influenced the pyrolysis and oxidation processes. Soot onset occurred at 1,450 K for oxygen levels of 0, 1, and 3 %, whereas at 5 % oxygen, soot formed at temperatures below 1,400 K. Interestingly, higher oxygen concentrations increased the rates of soot formation at all temperatures tested. By contrast, elevated temperatures reduce the total soot mass owing to enhanced oxidation. The present study also evaluates the influence of fuel composition on soot formation and observes that a higher aromatics content in the fuel leads to a lower soot onset temperature and increased soot mass. Notably, similar trends for both ethanol and n-dodecane fuels are identified in this study. Furthermore, the numerical calculations revealed distinct trends in PAH formation. Although the different mechanisms reasonably captured the trends in benzene formation, they differed in their predictions of the formation rate of pyrene, resulting in potential differences in soot processes. This disparity highlights the need for a comprehensive review and potential modification of the current soot modeling approach.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"21 ","pages":"Article 100310"},"PeriodicalIF":5.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pyrolysis and beyond: Sustainable valorization of plastic waste","authors":"Saumitra Saxena","doi":"10.1016/j.jaecs.2024.100311","DOIUrl":"10.1016/j.jaecs.2024.100311","url":null,"abstract":"<div><div>The recycling of plastics through pyrolysis has garnered significant attention as a waste management approach, particularly given upcoming regulations and the urgent need for absolute sustainability. This review paper evaluates pyrolysis's technological, environmental, and regulatory aspects, emphasizing the need to prioritize environmental impact over purely economic considerations. While it is recognized that financial challenges have constrained many past attempts at scaling pyrolysis systems, this paper argues that a shift in focus toward sustainability criteria is essential for the technology's long-term viability. Prioritizing environmental outcomes is critical given the pressing issues like plastic pollution, which presents significant threats to ecosystems and human health. A comprehensive assessment of environmental impacts is vital for technologies intended for large-scale deployment, ensuring that they align with global sustainability goals. This perspective is especially pertinent in light of the current United Nations Environment Programme (UNEP) global plastic pollution treaty negotiations, where there is a contentious debate over the true circularity of chemical recycling. Environmentalists and several nations advocate for significant reductions in plastic production and bans on single-use plastics. At the same time, oil-producing countries and petrochemical companies push for circularity in the plastic economy. The paper explores the promise and limitations of pyrolysis technology for valorizing plastic wastes, comparing its efficacy with other waste management methods. Biomass pyrolysis is discussed due to its significant synergies with plastic pyrolysis and its potential for carbon sequestration through biochar. However, the discussion on biomass pyrolysis is limited in scope, with the paper's primary focus on waste plastic pyrolysis. The paper discusses the challenges and opportunities in utilizing pyrolysis for waste plastics, which are considered along with regulatory and geopolitical aspects. Environmental impacts, including life cycle analysis and planetary boundary considerations, are examined to understand why pyrolysis has yet to achieve widespread adoption. A case study on Plastic Energy, SABIC, and Unilever highlights current industry status, technological advancements, and information gaps. Finally, a comprehensive framework is proposed to achieve net-zero emissions, improve air quality, and ensure absolute environmental sustainability in plastic recycling. Recommendations are provided for the plastic industry and research institutions to support the transition towards sustainable waste management practices.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"21 ","pages":"Article 100311"},"PeriodicalIF":5.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142756886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A perspective on the decarbonization of the metals industry","authors":"Alessandro Della Rocca","doi":"10.1016/j.jaecs.2024.100312","DOIUrl":"10.1016/j.jaecs.2024.100312","url":null,"abstract":"<div><div>The decarbonization of the metals industry is a major challenge for the energy transition. Metals are indeed essential elements in the expansion of renewable energy installations worldwide, but they also represent a relevant source of carbon emissions. Therefore, metals producers need to carefully shift their technologies towards less carbon intensive routes. After ranking all the metals in terms of world production volume and total estimated carbon emissions, the three most relevant ones have been selected: steel, aluminum and chromium. Concentrating the rest of the analysis on them, several production processes are available for implementing the decarbonization step, but none of them is currently capable of overcoming the challenge alone and being compatible with the 1.5 °C trajectory. In this perspective, the main production routes are reviewed and proper combinations of proven or emerging technologies are streamlined with the aim to provide an industrially feasible approach to curb the carbon emissions from the metals industry.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"21 ","pages":"Article 100312"},"PeriodicalIF":5.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal information propagation in confined supersonic reacting flows","authors":"Michael Ullman ,&nbsp;Gyu Sub Lee ,&nbsp;Jie Lim ,&nbsp;Tonghun Lee ,&nbsp;Venkat Raman","doi":"10.1016/j.jaecs.2024.100304","DOIUrl":"10.1016/j.jaecs.2024.100304","url":null,"abstract":"<div><div>The interplay between mass injection, heat release, and boundary layer development plays a key role in dictating the dynamics and stability of confined supersonic flows. The relative impacts of these factors and the timescales over which they influence the upstream and downstream flow can provide critical insights into how different operating modes develop. As such, this work presents a series of simulations of an experimental axisymmetric direct connect flowpath. The mass flow rates and chemical compositions of the injection stages are varied, and subsequent information propagation and mode transitions are analyzed using spatiotemporal correlations of cross-sectional averaged quantities. Increasing the injection flow rate decreases the time lags and durations of positive correlations between pressure and heat release at various points along the flowpath. Meanwhile, in dual-mode cases with lower injection flow rates, these correlations develop after longer time delays and persist for a longer times, illustrating how information propagates more gradually in these scenarios. Over the full flowpath, positive correlations persist for comparatively long times between (1) the upstream isolator pressure and the pressure elsewhere, and (2) the pressure in the downstream diverging combustor section and the upstream pressure. As such, the influence of the pressure in the intermediate constant-area combustor section decays more rapidly. Conditional statistics suggest that flow blockage and pressurization from the injected mass reduce the local ignition delay, thereby facilitating increased pressurization via heat release in a positive feedback loop.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"21 ","pages":"Article 100304"},"PeriodicalIF":5.0,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clean energy technology: Hydro-processing of waste tyre pyrolysis oil (WTPO) to diesel fuel in a continuous reactor using Co/SBA-15 catalyst","authors":"P. Tamizhdurai ,&nbsp;P. Arthi ,&nbsp;V.L. Mangesh ,&nbsp;P. Santhana Krishnan ,&nbsp;Nadavala Siva Kumar ,&nbsp;P. Saravanan ,&nbsp;A. Subramani ,&nbsp;P. Sasikumar ,&nbsp;Mohammed F. Alotibi ,&nbsp;Salwa B. Alreshaidan ,&nbsp;Abdulaziz A.M. Abahussain ,&nbsp;Ahmed S. Al-Fatesh ,&nbsp;R. Kumaran","doi":"10.1016/j.jaecs.2024.100305","DOIUrl":"10.1016/j.jaecs.2024.100305","url":null,"abstract":"<div><div>The need for sustainable fuel sources and efficient waste management has led researchers to explore innovative methods for converting waste into fuel. One promising avenue is the utilization of 100 % tyre oil (TO), which could offer a profitable and environmentally friendly solution for disposing of waste tyres. With rising fossil fuel costs, environmental concerns, and the challenges of waste tyre landfilling, there is increased interest in waste tyre pyrolysis oils (WTPO) as an alternative energy source. This study examines the hydro processed WTPO (HWTPO) was analysed using a metallic catalyst, specifically Co/SBA-15. This method involves hydrolysing WTPO with the metallic catalyst, assessing the physical-chemical properties, formulation efficiency compared to petroleum products, and diesel engine performance like the impact on fuel consumption, combustion, and emissions. The synthetic HWTPO's chemical and physical properties were found to be comparable to European diesel specifications (European standard 590). Under hydroprocessing conditions (80 bar and 375 °C), the Co/SBA-15 catalyst produced isoalkanes, n-alkanes, and aromatics in quantities nearly equivalent to 100 % diesel. HWTPO demonstrated the potential to maximize greenhouse gas emissions reduction and enhance the performance of diesel-powered engines. The favourable properties of HWTPO suggest that waste tyre pyrolysis oil could be a viable transportation fuel.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"21 ","pages":"Article 100305"},"PeriodicalIF":5.0,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerosol ignition in iron powder flames stabilized on a new type of jet-in-hot-coflow burner","authors":"J. Hameete,&nbsp;L.J. Boone,&nbsp;T.A.M. Homan,&nbsp;Y. Shoshyn,&nbsp;N.J. Dam,&nbsp;L.P.H. de Goey","doi":"10.1016/j.jaecs.2024.100301","DOIUrl":"10.1016/j.jaecs.2024.100301","url":null,"abstract":"<div><div>A novel Jet-in-Hot-Coflow burner for the combustion of solid metallic particles is presented. This system features an electrically preheated coflow to ignite particles without the need for a pilot flame, mimicking exhaust gas recirculation, a method often used in industry to suppress NO<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span> emissions and stabilize or control a combustion process. Two different iron powder samples with different particle size distributions were combusted, and their combustion products were analyzed using quantitative XRD to study the effect of particle size and interparticle heating on the ignition temperature of a suspension. It was found that a large fraction of the larger particles failed to ignite, probably due to insufficient heating during the residence time in the hot coflow. An increase in the dust concentration, expected to increase local temperatures and interparticle heating effects, did not significantly decrease the suspension ignition temperature for these powders.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"20 ","pages":"Article 100301"},"PeriodicalIF":5.0,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Future technological directions for hydrogen internal combustion engines in transport applications","authors":"J.W.G. Turner","doi":"10.1016/j.jaecs.2024.100302","DOIUrl":"10.1016/j.jaecs.2024.100302","url":null,"abstract":"<div><div>The paper discusses some of the requirements, drivers, and resulting technological paths for manufacturers to develop hydrogen combustion engines for use in two types of market application – on-road heavy- and light-duty. One of the main requirements is legislative certainty, and this has now been afforded – at least in the major market of Europe – by the European Union's recent adoption into law of tailpipe emissions limits specifically designed to encourage the uptake of hydrogen engines in heavy-duty vehicles, giving manufacturers the confidence they need to invest in productionized solutions to offer to customers.</div><div>It then discusses combustion systems and boosting systems for the two market types, emphasizing that heavy-duty vehicles need best efficiency throughout their operating map while light-duty ones, since they are rarely operated at full load, will mainly primarily need efficiency in the part-load region. This difference will likely cause a divergence in solutions, with heavy-duty engines running very lean everywhere and light-duty ones likely operating at the stoichiometric air-fuel ratio, at least for most of the map. The impacts of the strategies on engine systems and vehicle integration are discussed.</div><div>It is postulated that due to reasons of preignition avoidance and efficiency hydrogen engines will rapidly adopt direct injection and that the long-term heavy-duty types will migrate towards the typical current spark-ignition-type cylinder head architecture where tumble, rather than swirl, will ultimately be needed for air motion in the cylinder for these reasons. They may also adopt active pre-chamber technology to ignite extremely lean mixtures for maximum efficiency and minimum emissions of oxides of nitrogen.</div><div>It is suggested that light-duty engines will evolve less from their current gasoline architectural norm since they already contain all of the necessary fundamentals for hydrogen combustion. However, since part-load efficiency will be important, some new strategies may become desirable. Developing dual-fuel light-duty engines could accelerate their uptake as the heavy-duty market simultaneously accelerates the creation of the fuel supply infrastructure.</div><div>The likely technological evolution suggests that variable valve trains, and specifically cam profile switching technology, would be extremely useful for all types of hydrogen engine, especially since they are readily available in different gasoline engines now. New operating strategies afforded by variable valve trains would benefit both heavy- and light-duty engines, and these strategies will become more sophisticated. There will therefore likely be a convergence of technologies for the two markets, albeit with some key differences maintained due to their vehicle applications and their differing operation in the field.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"21 ","pages":"Article 100302"},"PeriodicalIF":5.0,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of flame temperature on structure and CO oxidation properties of Pt/CeO2 catalyst by flame-assisted spray pyrolysis","authors":"Naoya Minegishi ,&nbsp;Peizhou Li ,&nbsp;Tsuyoshi Nagasawa ,&nbsp;Hidenori Kosaka","doi":"10.1016/j.jaecs.2024.100303","DOIUrl":"10.1016/j.jaecs.2024.100303","url":null,"abstract":"<div><div>Flame synthesis offers the potential for the synthesis of structure-controlled catalysts. In this study, Pt/CeO₂ nanoparticles were synthesized via flame-assisted spray pyrolysis (FASP) and used as CO oxidation catalysts. The catalysts were synthesized using a burner diffusion flame at three different flame temperatures (maximum flame temperatures, <span><math><msub><mi>T</mi><mi>f</mi></msub></math></span> = 1556, 1785, and 2026 K), and their particle structure and CO oxidation activity were evaluated. The synthesized Pt/CeO₂ catalysts had a bimodal structure containing 100 nm-scale CeO₂ loaded with 10 nm-scale Pt and fine CeO₂ &lt; 10 nm loaded with highly dispersed Pt (less than 1 nm). As the flame temperature increases from 1556 to 2026 K, the formation of fine CeO₂ particles dominates, resulting in an increase in BET specific surface area from 7.97 to 112 m²/g and Pt dispersion from 4.67 to 20.6%. Insight into the particle formation routes that determine the catalyst structure is provided by numerical simulation of droplet evaporation in a burner flame. CO oxidation experiments showed that the temperature at which CO conversion reached 100% (<em>T</em>₁₀₀) decreased from 513 to 378 K with increasing flame temperature in FASP. In addition, the thermal stability test showed that the Pt dispersion after thermal degradation was higher for Pt/CeO₂ catalyst made by FASP at <span><math><msub><mi>T</mi><mi>f</mi></msub></math></span> = 2026 K than that prepared by the impregnation method, and the <em>T</em>₁₀₀ for CO oxidation was lower by 20 K.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"20 ","pages":"Article 100303"},"PeriodicalIF":5.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}