Applications in Energy and Combustion Science最新文献

{"title":"Characterization of detonation waves by simultaneous OH and NO planar laser-induced fluorescence","authors":"Samir B. Rojas Chavez, Karl P. Chatelain, Mhedine Alicherif, Deanna A. Lacoste","doi":"10.1016/j.jaecs.2024.100257","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100257","url":null,"abstract":"<div><p>This study presents a thorough evaluation of the simultaneous planar laser-induced fluorescence (PLIF) on hydroxyl (OH) radicals and nitric oxide (NO), for characterizing hydrogen detonation fronts. The study combines experimental and numerical results to evaluate the benefits and drawbacks of different visualization strategies, namely OH-PLIF alone, NO-PLIF alone, OH-PLIF + shock det. (comparable to simultaneous OH-PLIF and schlieren), and combined OH- and NO-PLIF. Main findings are: (i) For the first time, simultaneous single-shot OH- and NO-PLIF visualizations are demonstrated on detonation waves for three mixtures with varying stability levels: Mixture (a) 2H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-O<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-3.76Ar, Mixture (b) 2H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-O<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-3.76N<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and Mixture (c) 3H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-CH<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>-3.5O<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-3.76Ar; (ii) the simultaneous visualization evidences the self-similarity of both techniques, with a clear interlock of OH-PLIF imaging into NO-PLIF imaging. This means that the structure of the OH-reaction zone, typically visualized from OH-PLIF, can be accurately described from NO-PLIF imaging alone, from which induction zones can also be visualized. In addition, both can clearly depict the wrinkling of the front and the presence of unburned pockets; (iii) the effectiveness of the four visualization strategies at characterizing the detonation wave of a H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-O<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-3.76Ar mixture is determined using ZND and spectroscopic simulations. Interestingly, the induction zone (<span><math><msub><mrow><mi>Δ</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>) is more accurately predicted by NO-PLIF (3% error) than with the combined OH + shock det. (10% error). This study highlights the potential of NO-PLIF diagnostic in characterizing detonation waves with low levels of confinement (i.e., <span><math><mrow><mi>d</mi><mo>/</mo><mi>λ</mi><mo>></mo><mo>></mo><mo>></mo><mn>1</mn></mrow></math></span>) both qualitatively (e.g., reaction zone structure) and quantitatively (e.g., <span><math><msub><mrow><mi>Δ</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> measurements) using a single diagnostic. Additionally, the simultaneous OH- and NO-PLIF diagnostic may offer significant advantages in characterizing the detonation waves in engine-relevant conditions (i.e., in complex geometries with ","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100257"},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000128/pdfft?md5=092dc0c154ff616f702b296a2da102ee&pid=1-s2.0-S2666352X24000128-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140030143","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":"Unraveling the impact of CO2 exhaust gas recirculation on flame characteristics and NOx emissions of premixed NH3/DME swirl flames","authors":"Tianyou Lian ,&nbsp;Xiaoxiang Shi ,&nbsp;Sibo Han,&nbsp;Yi Zhang,&nbsp;Zundi Liu,&nbsp;Zhongya Xi,&nbsp;Wei Li,&nbsp;Yuyang Li","doi":"10.1016/j.jaecs.2024.100256","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100256","url":null,"abstract":"<div><p>The low combustion intensity and high NOx emissions of ammonia (NH₃) pose challenges to its applications in energy and power devices. Co-firing strategies with reactive fuels, such as hydrogen, methane, syngas, and dimethyl ether (DME), have been proposed to enhance the combustion stability of NH₃ in gas turbine, while exhaust gas recirculation (EGR) has the potential to reduce NOx emissions of combustion systems. This work explores the impact of CO₂ EGR on the flame characteristics and NOx emissions of premixed NH₃/DME swirl flames. CO₂ EGR is observed to have a profound impact on both flame morphology and chemiluminescence intensity. With increasing CO₂ EGR rate, which is described by the CO₂ content in the oxidizer (<span><math><msub><mi>χ</mi><mrow><mi>C</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></msub></math></span>), the chemiluminescence intensity becomes much weaker, the flame height rises, and the lean blowout (LBO) limit grows, indicating a reduced flame stability. Moreover, CO₂ EGR affects the distribution of OH radical and weakens the OH fluorescence intensity. These impacts on flame characteristics mean that practical energy and power devices should be better designed to stabilize the flame. To unravel the underlying mechanism, kinetic analysis on premixed NH₃/DME/air flame under non-EGR and CO₂ EGR conditions is performed. Simulation results show that CO₂ EGR substantially reduces the laminar burning velocity, maximum OH mole fraction, and NO mole fraction. The reduction of NO mole fraction is mainly attributed to the thermal effect of CO₂ EGR. The chemical effect plays a positive role in reducing NO formation under lean conditions but enhances NO formation under rich conditions.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"17 ","pages":"Article 100256"},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000116/pdfft?md5=f4d65352b2b7772a4ef1a65747c60736&pid=1-s2.0-S2666352X24000116-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139718904","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":"Hydrogen fuel cell electric trains: Technologies, current status, and future","authors":"Daniel Ding,&nbsp;Xiao-Yu Wu","doi":"10.1016/j.jaecs.2024.100255","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100255","url":null,"abstract":"<div><p>Trains have been a crucial part of modern transport, and their high energy efficiency and low greenhouse gas emissions make them ideal candidates for the future transport system. Transitioning from diesel trains to hydrogen fuel cell electric trains is a promising way to decarbonize rail transport. That's because the fuel cell electric trains have several advantages over other electric trains, such as lower life-cycle emissions and shorter refueling time than battery ones, and less requirements for wayside infrastructure than the ones with overhead electric wires. However, hydrogen fuel technology still needs to be advanced in areas including hydrogen production, storage, refueling, and on-board energy management. Currently, there are several pilot projects of hydrogen fuel cell electric trains across the globe, especially in developed countries, including one commercialized and permanent route in Germany. The experiences from the pilot projects will promote the technological and economic feasibility of hydrogen fuel in rail transport.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"17 ","pages":"Article 100255"},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000104/pdfft?md5=6d05397ed102e0239013548b9ad93f69&pid=1-s2.0-S2666352X24000104-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139713786","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":"Ignition characteristics of hydrogen-enriched ammonia/air mixtures","authors":"Stefan Essmann ,&nbsp;Jessica Dymke ,&nbsp;Jacqueline Höltkemeier-Horstmann ,&nbsp;Dieter Möckel ,&nbsp;Carola Schierding ,&nbsp;Michael Hilbert ,&nbsp;Chunkan Yu ,&nbsp;Ulrich Maas ,&nbsp;Detlev Markus","doi":"10.1016/j.jaecs.2024.100254","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100254","url":null,"abstract":"<div><p>Ammonia is an attractive hydrogen carrier and potential fuel which could play a role in decarbonizing process heat, power or transport applications. However, the combustion properties of ammonia are disadvantageous for many technical processes. Hydrogen addition has been shown to mitigate this challenge by increasing the laminar burning velocity and extending the lean blow-off limit. In this work, the ignition characteristics of hydrogen enriched ammonia/air mixtures are investigated experimentally. A capacitive discharge is used to ignite the mixture. The effects of an increasing share of hydrogen in the fuel are a drastic decrease in ignition energy as well as an increase in explosion pressure and the rate of pressure rise. Further, schlieren imaging was employed to study the structure and evolution of the flame kernel shortly after ignition. Due to the high discharge energy necessary to ignite ammonia/air, the flame kernel evolution is dominated by the discharge.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"17 ","pages":"Article 100254"},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000098/pdfft?md5=01ea3ea1fc3962a153edd3428e3b382f&pid=1-s2.0-S2666352X24000098-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139674828","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":"Effects of preferential diffusion and flame stretch on FGM method for numerical simulations of ammonia/air premixed combustion","authors":"Reo Kai,&nbsp;Shinya Ayukawa,&nbsp;Kazuhiro Kinuta,&nbsp;Ryoichi Kurose","doi":"10.1016/j.jaecs.2024.100253","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100253","url":null,"abstract":"<div><p>Importance of the considerations of preferential diffusion and flame stretch effects in the flamelet-generated manifold (FGM) method on the prediction accuracy is investigated by two-dimensional numerical simulations of cylindrical NH₃/air premixed flames, under the conditions of an unburnt gas temperature of 673<!--> <!-->K, an ambient pressure of 2<!--> <!-->MPa, and equivalence ratios of 0.8 to 1.2. Results of the numerical simulations using the detailed chemistry, in which 32 species and 204 reactions are directly solved in the physical space without the FGM method, show that the mixture fraction in the burnt gas increases from the unburnt gas value when considering the preferential diffusion effect, whereas it remains flat when assuming the unity Lewis number. This means that assuming the unity Lewis number causes the underprediction and overprediction of the burnt gas temperature under fuel-lean and fuel-rich conditions, respectively. Results of the numerical simulations using the FGM methods show that considering the preferential diffusion and flame stretch effects in the FGM method is important for accurate prediction of the flame propagating speed, and the effectiveness is more evident for the flame stretch effect than for the preferential diffusion effect for the NH₃/air premixed flames.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"17 ","pages":"Article 100253"},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000086/pdfft?md5=64c88eaaae862b321d148207310e63cf&pid=1-s2.0-S2666352X24000086-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139682633","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":"Intracavity laser absorption spectroscopy: Performance and advantages for energy science","authors":"Uri Zamir ,&nbsp;Joshua H. Baraban ,&nbsp;Peter Fjodorow ,&nbsp;Igor Rahinov","doi":"10.1016/j.jaecs.2024.100251","DOIUrl":"10.1016/j.jaecs.2024.100251","url":null,"abstract":"<div><p>Meeting the demands of sustainable energy economy requires diagnostics of the chemical processes surrounding future fuels and contemporary combustion applications. Pioneered in 1970, Intracavity Laser Absorption Spectroscopy (ICAS) has evolved to be a powerful instrument in the toolbox of combustion diagnostics. It owes its ultra-high sensitivity to the enhancement of the effective absorption pathlength by placing the absorber inside the cavity of a broadband laser. In this review we introduce the complementary strengths of ICAS to other methods: ultra-high sensitivity to narrowband absorption alongside the immunity to broadband losses, multiplexed detection and (µs-scale)-temporal resolution. We outline the basic concepts and features of ICAS, focusing on the laser dynamics regime where an absorbing sample in the laser resonator yields the well-known Lambert-Beer law. We chart the progress made over the years in visible (dye-jet laser) and near infrared (fiber laser) ICAS speciation in flames, by highlighting case studies where species like long considered \"hard-to detect\" ¹CH₂ and HCO radicals, along with O-atoms, C₂, NH₂, HNO, CN, and HCN were measured, as well as thermometry and speciation applications demonstrated in shock tubes, flow-cells and flames based on (stationary or time-resolved) measurements of multicomponent spectral matrices containing lines of CH₄, C₂H₂, CO₂, CO, OH and H₂O. We highlight the contributions of ICAS in gas-phase nanomaterial synthesis, exemplified in prototypical iron-doped flames and discuss prospective applications in spray-flame pyrolysis and metal-powder combustion. Finally, we present advances in the development of lasing media based on Cr²⁺ and Fe²⁺-doped chalcogenide crystals and fluoride crystals doped with trivalent lanthanides, that meet the (ICAS-specific) requirement associated with the necessity to have a gain media lasing directly in the desired wavelength range, and therefore to expand this technique into the important mid-infrared and ultraviolet spectral ranges.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"17 ","pages":"Article 100251"},"PeriodicalIF":0.0,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000062/pdfft?md5=0e6c67e351695046585f666027f6140b&pid=1-s2.0-S2666352X24000062-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139631319","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":"Spray-flame synthesis of Nb-doped TiO2 nanoparticles and their electrochemical performance in sodium-ion batteries","authors":"Alexander Eitner ,&nbsp;Ahmed K. Al-Kamal ,&nbsp;Md Yusuf Ali ,&nbsp;Mohammed-Ali Sheikh ,&nbsp;Christof Schulz ,&nbsp;Hartmut Wiggers","doi":"10.1016/j.jaecs.2024.100252","DOIUrl":"10.1016/j.jaecs.2024.100252","url":null,"abstract":"<div><p>TiO₂ nanomaterials are attractive anode materials in sodium-ion batteries (SIBs) and doping with niobium is known to improve the electronic conductivity as well as the kinetics of the de-/intercalation of Na⁺ ions. These effects are related to the formation of defects and lattice widening, leading to improved rate capability and stability. We report single-step synthesis of niobium-doped TiO₂ nanoparticles by scalable spray-flame synthesis from titanium(IV) isopropoxide (TTIP) dissolved in mixtures of ethanol and ethyl hexanoic acid. Niobium(V) ethoxide was identified as the preferred precursor and materials with varying Nb/Ti ratios were synthesized. SEM/EDX analysis of the as-synthesized powders confirmed Nb/Ti ratios near to the target ratios determined by the precursor mixture. XRD with Rietveld refinement revealed the dependence of the lattice parameters on doping. The materials synthesized mainly consist of anatase with a minor contribution of rutile and Nb₂O₅ at higher doping concentration. The increase of lattice parameters with higher Nb/Ti ratios, the formation of Nb-O-Ti bonds, and the detected main oxidation state of +5 of Nb indicate successful incorporation of Nb⁵⁺ into the TiO₂ lattice and impedance measurements indicate higher electronic conductivity for the Nb-doped TiO₂ in comparison to the undoped TiO₂. The best electrochemical performance was observed for a material with 2 at.% Nb, which delivered high reversible capacity of 194 mAh/g at 0.1 C and 83.7 ± 1.5% capacity retention at 0.5 C after 100 cycles. Moreover, rate capability tests indicate higher Na⁺ diffusion kinetics in the Nb-doped samples. This one-step synthesis route of these high-performing doped TiO₂ nanomaterials provides promising anode material for sodium-ion batteries.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"17 ","pages":"Article 100252"},"PeriodicalIF":0.0,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000074/pdfft?md5=0b66154a50bb6bd2e08e68cff258cd55&pid=1-s2.0-S2666352X24000074-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139631930","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 ignition pattern on combustion characteristics in a hydrogen Wankel rotary engine: A numerical study","authors":"Huaiyu Wang ,&nbsp;James Turner ,&nbsp;Xin Wang ,&nbsp;Yunshan Ge ,&nbsp;Liqun Lyu ,&nbsp;Shuofeng Wang ,&nbsp;Changwei Ji ,&nbsp;Jinxin Yang","doi":"10.1016/j.jaecs.2024.100250","DOIUrl":"10.1016/j.jaecs.2024.100250","url":null,"abstract":"<div><p>Hydrogen is considered the optimal solution for achieving high efficiency and low emissions in Wankel rotary engines (WREs). This paper aims to reveal the effect of ignition patterns on the combustion process of a hydrogen-fueled WRE. The results show that the combustion rate of the trailing spark plug (TSP), due to its structural similarity with the passive precombustion chamber, surpasses that of the leading spark plug (LSP). The unidirectional flow field promotes the forward development of the flame of TSP but inhibits the backward development of the flame of LSP. Moreover, the recess in combustion chamber facilitates flame propagation of TSP. Asynchronous ignition mode exhibits a higher indicated thermal efficiency (ITE) than synchronous ignition mode, facilitating effective control of the combustion phase. When the ignition timing of LSP is delayed, and TSP is earlier, the flame of TSP exceeds LSP, resulting in unchanged ITE. When the ignition timing of TSP is delayed, and LSP is earlier, the peak of free radicals and burned volume rate are the highest, resulting in a faster combustion rate. It is recommended that the LSP ignition timing is set earlier for practical operations.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"17 ","pages":"Article 100250"},"PeriodicalIF":0.0,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000050/pdfft?md5=46b6478c46d6c38ead1c0e1eb319b6aa&pid=1-s2.0-S2666352X24000050-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139537553","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":"Effects of cathode gas diffusion layer porosity and contact angle distributions along through-plane direction on the performance of polymer electrolyte membrane fuel cell","authors":"Huadong Yu ,&nbsp;Haiou Wang ,&nbsp;Dongwei Yao ,&nbsp;Kun Luo ,&nbsp;Jianren Fan","doi":"10.1016/j.jaecs.2024.100249","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100249","url":null,"abstract":"<div><p>In the present work, a numerical model for polymer electrolyte membrane fuel cell (PEMFC) has been employed to investigate the effects of porosity and contact angle distributions of the porous layer on the performance of PEMFC. The three-dimensional, two-phase, and non-isothermal flow solver considers heat transfer, electrochemical reaction, and liquid water saturation. Various cases with different cathode gas diffusion layer (GDL) porosities are performed. The results showed that a better performance is achieved when the GDL porosity is increased because of the reduced mass transport resistance of oxygen. The effects of the porosity distributions on the PEMFC performance were examined by comparing the predictions from the cases with non-uniform porosity and uniform porosity in the cathode GDL. It was shown that the current density of the cases with non-uniform porosity is higher than that of the uniform porosity case when the operation voltage is low. This is due to the fact that non-uniform porosity distributions in the cathode GDL enhance the reactant transport. When the operation voltage is high, the current densities of the cases with non-uniform porosity and uniform porosity are almost the same. Moreover, the influence of contact angle distributions in cathode GDL was explored. Various cases with gradient-decreasing, gradient-increasing, and uniform constant contact angles from GDL/channel interface to GDL/catalyst layer interface were studied. It was found that the case with gradient-increasing contact angle has a better performance due to the larger capillary pressure difference to remove more water. The poor performance of the case with gradient-decreasing contact angle is related to the phenomenon of flooding in the catalyst layer.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"17 ","pages":"Article 100249"},"PeriodicalIF":0.0,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000049/pdfft?md5=3a9e8eed040918c9bb6e360ca442763c&pid=1-s2.0-S2666352X24000049-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139473373","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 investigation of multi-burner array with lean lifted spray flames in inline and inclined configurations","authors":"Mohamed Shamma,&nbsp;Stefan Harth,&nbsp;Dimosthenis Trimis","doi":"10.1016/j.jaecs.2024.100246","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100246","url":null,"abstract":"<div><p>Lean combustion in gas turbines garners attention for emissions reduction, yet it faces stability challenges demanding careful design considerations. In this study, a novel CHAIRLIFT combustor concept, which integrates low swirl lean lifted spray flames known for substantial nitrogen oxides emissions reduction, into a Short Helical Combustors (SHC) arrangement, is investigated. A comprehensive experimental test campaign explores key parameters, including staggered arrangement offset, equivalence ratios, and air inlet temperature, to evaluate its performance. The results reveal exceptional stability in low swirl, lifted flames compared to moderate swirl flames with larger inner recirculation zones. The unwanted flow deflection of highly swirled flames in the SHC arrangement is effectively avoided with the investigated low swirl, lifted flames. The study emphasizes the significant influence of fuel droplet evaporation time on flame stability near the flame root under low air inlet temperatures. Furthermore, at high air inlet temperatures, the complex flame stability mechanism in inclined configurations is controlled by various parameters, including outer recirculation zone size, air inlet temperature, and additional vortices generated by pressure differences near the wall. <span><math><mrow><mi>O</mi><msup><mrow><mi>H</mi></mrow><mrow><mo>∗</mo></mrow></msup></mrow></math></span> chemiluminescence results corroborate these stability mechanisms, showing that at lower temperatures, the flame stabilizes closer to the nozzle exit due to local rich pockets near the shear layer. Conversely, at the same tilt angle, higher air inlet temperatures lead to an increased flame lift-off height due to faster evaporation and enhanced mixing. Exhaust gas analyses confirm the potential of the investigated lean lifted spray flames in a multi-burner arrangement to achieve very low NO_x emissions over a wide range of operating conditions for all investigated burner inclinations. These findings may facilitate the future development and optimization of lean combustion technology for aircraft engines.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"17 ","pages":"Article 100246"},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000013/pdfft?md5=12e4c1a515b23d516134a3da92a33fd9&pid=1-s2.0-S2666352X24000013-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139434300","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}