Pub Date : 2026-01-23DOI: 10.1016/j.jaecs.2026.100464
Juan Camilo Giraldo Delgado, Qi Wang, S. Mani Sarathy
Thermoacoustic instabilities pose a significant challenge in combustion applications, leading to potential damage to rocket engines and gas turbines. Among various mitigation strategies, active control has been explored as a mean to decouple acoustics from heat release in combustion systems. Due to the highly nonlinear nature of thermoacoustic instabilities, machine learning methodologies have gained attention to enhance active control strategies. In particular, prior studies have shown that classical phase-shift control can be improved by adapting its parameters using Reinforcement Learning (RL). In this study, we investigated the application of Offline RL to leverage existing datasets for mitigating thermoacoustic instabilities in a laminar premixed flame. The methodology uses data collected from a closed-loop experimental setup operating under a phase-shift control strategy. The gain and time delay were recorded, and Implicit Q Learning (IQL) was then used to train a neural network (actor) to determine these parameters based on observations of chemiluminescence and pressure fluctuations in the flame. The training procedure was conducted offline, and upon experimental deployment, the trained neural network successfully reduced thermoacoustic instabilities. These results highlight the potential of Offline RL for combustion control applications.
{"title":"Offline reinforcement learning for mitigating thermoacoustic instabilities in a laminar premixed flame","authors":"Juan Camilo Giraldo Delgado, Qi Wang, S. Mani Sarathy","doi":"10.1016/j.jaecs.2026.100464","DOIUrl":"10.1016/j.jaecs.2026.100464","url":null,"abstract":"<div><div>Thermoacoustic instabilities pose a significant challenge in combustion applications, leading to potential damage to rocket engines and gas turbines. Among various mitigation strategies, active control has been explored as a mean to decouple acoustics from heat release in combustion systems. Due to the highly nonlinear nature of thermoacoustic instabilities, machine learning methodologies have gained attention to enhance active control strategies. In particular, prior studies have shown that classical phase-shift control can be improved by adapting its parameters using Reinforcement Learning (RL). In this study, we investigated the application of Offline RL to leverage existing datasets for mitigating thermoacoustic instabilities in a laminar premixed flame. The methodology uses data collected from a closed-loop experimental setup operating under a phase-shift control strategy. The gain and time delay were recorded, and Implicit Q Learning (IQL) was then used to train a neural network (actor) to determine these parameters based on observations of chemiluminescence and pressure fluctuations in the flame. The training procedure was conducted offline, and upon experimental deployment, the trained neural network successfully reduced thermoacoustic instabilities. These results highlight the potential of Offline RL for combustion control applications.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"25 ","pages":"Article 100464"},"PeriodicalIF":5.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-21DOI: 10.1016/j.jaecs.2026.100465
Daisuke Sato , Jordan Davies , Syed Mashruk , Agustin Valera-Medina , Ryoichi Kurose
Renewably produced ammonia does not emit CO2 with combustion. Therefore, numerous studies have been conducted in recent years to utilise ammonia as a carbon free fuel. However, there is limited previous knowledge regarding the radiation characteristics of ammonia blend combustion. In this study, radiation characteristics are investigated for 15 kW premixed swirling flames of NH3/H2 (70/30) and 20% cracked NH3, which have been frequent targets of recent research, with equivalence ratios varying from 0.6 ≤ Φ ≤ 1.4. Specifically, water radiation (wavelength 2.7 μm), which is the main radiation source, is measured using an infrared spectrometer. Additionally, radiation emission and absorption in the combustor are evaluated theoretically using H2O exhaust gas concentrations and temperature measurement data. The results suggest that radiation changes due to equivalence ratio variations are gradual on the rich side, showing different trends compared to the lean side. Furthermore, radiation attenuation in the combustor become active around Φ = 0.9. This suggests that when considering radiation in ammonia blend combustion, not only the blend composition but also equivalence ratio conditions must be carefully considered. In addition, radiative heat fluxes were analysed for three blends (NH3/H2, pure NH3, and cracked NH3) at Φ = 1.0, suggesting no significant differences in radiative heat flux among these blends. These research findings provide valuable insights for future combustor designs using ammonia blend fuels.
{"title":"Radiative characteristics of premixed ammonia-hydrogen and cracked ammonia swirling flames","authors":"Daisuke Sato , Jordan Davies , Syed Mashruk , Agustin Valera-Medina , Ryoichi Kurose","doi":"10.1016/j.jaecs.2026.100465","DOIUrl":"10.1016/j.jaecs.2026.100465","url":null,"abstract":"<div><div>Renewably produced ammonia does not emit CO<sub>2</sub> with combustion. Therefore, numerous studies have been conducted in recent years to utilise ammonia as a carbon free fuel. However, there is limited previous knowledge regarding the radiation characteristics of ammonia blend combustion. In this study, radiation characteristics are investigated for 15 kW premixed swirling flames of NH<sub>3</sub>/H<sub>2</sub> (70/30) and 20% cracked NH<sub>3</sub>, which have been frequent targets of recent research, with equivalence ratios varying from 0.6 ≤ Φ ≤ 1.4. Specifically, water radiation (wavelength 2.7 μm), which is the main radiation source, is measured using an infrared spectrometer. Additionally, radiation emission and absorption in the combustor are evaluated theoretically using H<sub>2</sub>O exhaust gas concentrations and temperature measurement data. The results suggest that radiation changes due to equivalence ratio variations are gradual on the rich side, showing different trends compared to the lean side. Furthermore, radiation attenuation in the combustor become active around Φ = 0.9. This suggests that when considering radiation in ammonia blend combustion, not only the blend composition but also equivalence ratio conditions must be carefully considered. In addition, radiative heat fluxes were analysed for three blends (NH<sub>3</sub>/H<sub>2</sub>, pure NH<sub>3</sub>, and cracked NH<sub>3</sub>) at Φ = 1.0, suggesting no significant differences in radiative heat flux among these blends. These research findings provide valuable insights for future combustor designs using ammonia blend fuels.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"25 ","pages":"Article 100465"},"PeriodicalIF":5.0,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1016/j.jaecs.2026.100463
Mohamed E. Mohamed , Trent D. Penman , Jacques De Beer , Stanislav I. Stoliarov , Gavin P. Horn , Alexander I. Filkov
Firebrand accumulation in the form of piles significantly contribute to structural losses in the Wildland-Urban Interface. Decking materials may be particularly vulnerable to ignition from firebrand piles. However, large-scale studies replicating real-world conditions are still lacking. This study investigates the observed thermal response of Pressure Treated Wood (PTW) and Trex Enhance (Trex) composite decking under exposure to 8 grams firebrand piles (10 cm × 5 cm x 2 cm) at large-scale decking assembly (60 cm × 60 cm). Experimental conditions involved different constant wind speed (1.4 m s-1 and 2.7 m s-1); moisture content (MC) of tested materials (PTW: 26% and 7%; Trex: <1%); and firebrand pile orientation (0°: 10 cm side parallel to airflow; and 90°: 10 cm side perpendicular to airflow). For PTW experiments, three key events were observed: 1) Burn-through: when the samples experienced vertical propagation until a glowing-edged opening >5 mm appeared at the back surface; 2) Back surface flaming ignition: when transition from smouldering to intense flaming ignition took place at the back surface; and 3) Back surface re-ignition: when flaming ignition appeared second time at the back surface but at lower intensity. For PTW, the higher wind speed (2.7 m s-1) was the dominant factor associated with significantly increased likelihood of burn-through and was a necessary factor in inducing back surface flaming. The low MC (7%) also increased the propensity for burn-through and back surface flaming, though to a lesser extent. Although firebrand pile orientation showed insignificant impact on the overall thermal response, it still played a critical role. The 90° orientation increased the burn-through propensity, while 0° orientation displayed a greater tendency for back surface flaming and its associated characteristics. Compared to PTW, Trex exhibited considerably lower combustion intensity and duration, with no observations of burn-through or back surface flaming in any experiment.
以桩的形式堆积的火种对荒地-城市界面的结构损失起着重要的作用。铺装材料可能特别容易被火把桩点燃。然而，复制现实世界条件的大规模研究仍然缺乏。本研究调查了压力处理木材（PTW）和Trex Enhance （Trex）复合甲板在暴露于8克火焰桩（10厘米× 5厘米× 2厘米）下的热响应，并进行了大规模甲板组装（60厘米× 60厘米）。实验条件包括不同恒定风速（1.4 m s-1和2.7 m s-1）；测试材料的含水率（MC） （PTW: 26%和7%；Trex: 1%）；火种桩方向（0°：10 cm侧与气流平行；90°：10 cm侧与气流垂直）。对于PTW实验，观察到三个关键事件：1)烧透：当样品经历垂直传播时，直到背面出现5 mm的发光边缘开口；2)后表面燃烧着火：当后表面由闷烧过渡到强烈燃烧着火时；3)后表面重燃：后表面出现第二次火焰点火，但强度较低。对于PTW，较高的风速（2.7 m s-1）是显著增加烧透可能性的主导因素，也是诱发后表面燃烧的必要因素。低MC（7%）也增加了烧透和背面燃烧的倾向，尽管程度较小。火种桩取向对整体热响应的影响不显著，但仍发挥着关键作用。90°取向增加了烧透倾向，而0°取向对后表面燃烧及其相关特征表现出更大的倾向。与PTW相比，Trex表现出相当低的燃烧强度和持续时间，在任何实验中都没有观察到烧透或背面燃烧。
{"title":"Evaluating the thermal response of large-scale decking assemblies exposed to firebrand piles","authors":"Mohamed E. Mohamed , Trent D. Penman , Jacques De Beer , Stanislav I. Stoliarov , Gavin P. Horn , Alexander I. Filkov","doi":"10.1016/j.jaecs.2026.100463","DOIUrl":"10.1016/j.jaecs.2026.100463","url":null,"abstract":"<div><div>Firebrand accumulation in the form of piles significantly contribute to structural losses in the Wildland-Urban Interface. Decking materials may be particularly vulnerable to ignition from firebrand piles. However, large-scale studies replicating real-world conditions are still lacking. This study investigates the observed thermal response of Pressure Treated Wood (PTW) and Trex Enhance (Trex) composite decking under exposure to 8 grams firebrand piles (10 cm × 5 cm x 2 cm) at large-scale decking assembly (60 cm × 60 cm). Experimental conditions involved different constant wind speed (1.4 m s<sup>-1</sup> and 2.7 m s<sup>-1</sup>); moisture content (MC) of tested materials (PTW: 26% and 7%; Trex: <1%); and firebrand pile orientation (0°: 10 cm side parallel to airflow; and 90°: 10 cm side perpendicular to airflow). For PTW experiments, three key events were observed: 1) Burn-through: when the samples experienced vertical propagation until a glowing-edged opening >5 mm appeared at the back surface; 2) Back surface flaming ignition: when transition from smouldering to intense flaming ignition took place at the back surface; and 3) Back surface re-ignition: when flaming ignition appeared second time at the back surface but at lower intensity. For PTW, the higher wind speed (2.7 m s<sup>-1</sup>) was the dominant factor associated with significantly increased likelihood of burn-through and was a necessary factor in inducing back surface flaming. The low MC (7%) also increased the propensity for burn-through and back surface flaming, though to a lesser extent. Although firebrand pile orientation showed insignificant impact on the overall thermal response, it still played a critical role. The 90° orientation increased the burn-through propensity, while 0° orientation displayed a greater tendency for back surface flaming and its associated characteristics. Compared to PTW, Trex exhibited considerably lower combustion intensity and duration, with no observations of burn-through or back surface flaming in any experiment.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"25 ","pages":"Article 100463"},"PeriodicalIF":5.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigated the effects of blending weight ratio of 5% and 10% ethanol (B7E5 and B7E10) with standard B7-diesel on the performance, combustion, and emission characteristics of a light-duty common-rail diesel engine. The engine was tested on a dynamometer across various speeds (1600–2000 rpm) and loads (84 and 112 Nm) to analyze in-cylinder pressure, thermal efficiencies, and exhaust emissions. Results indicated significant emission benefits, especially at high loads. The B7E10 blend reduced smoke intensity by approximately 75% and carbon dioxide emissions by 34% compared to the baseline B7. The performance analysis revealed a critical trade-off associated with the ethanol blends: while the inherent oxygen content in ethanol significantly improved the indicated thermal efficiency (ITE) through enhanced combustion, its lower viscosity simultaneously led to increased frictional losses. Consequently, these competing effects resulted in only a modest improvement in brake thermal efficiency (BTE) and comparable brake-specific energy consumption (BSEC) compared to the baseline B7. The primary objective is to identify the benefits and trade-offs associated with ethanol blending in biodiesel-based diesel fuels that are compatible with existing diesel vehicles.
{"title":"Influence of ethanol-blended B7-diesel on in-cylinder combustion characteristic, engine thermal efficiency and emission of a 3L-compression ignition engine","authors":"Teerapat Suteerapongpun , Poonnut Thaeviriyakul , Watanyoo Phairote , Peerawat Saisirirat , Watcharin Po-ngaen , Hidenori Kosaka , Preechar Karin","doi":"10.1016/j.jaecs.2026.100461","DOIUrl":"10.1016/j.jaecs.2026.100461","url":null,"abstract":"<div><div>This study investigated the effects of blending weight ratio of 5% and 10% ethanol (B7E5 and B7E10) with standard B7-diesel on the performance, combustion, and emission characteristics of a light-duty common-rail diesel engine. The engine was tested on a dynamometer across various speeds (1600–2000 rpm) and loads (84 and 112 Nm) to analyze in-cylinder pressure, thermal efficiencies, and exhaust emissions. Results indicated significant emission benefits, especially at high loads. The B7E10 blend reduced smoke intensity by approximately 75% and carbon dioxide emissions by 34% compared to the baseline B7. The performance analysis revealed a critical trade-off associated with the ethanol blends: while the inherent oxygen content in ethanol significantly improved the indicated thermal efficiency (ITE) through enhanced combustion, its lower viscosity simultaneously led to increased frictional losses. Consequently, these competing effects resulted in only a modest improvement in brake thermal efficiency (BTE) and comparable brake-specific energy consumption (BSEC) compared to the baseline B7. The primary objective is to identify the benefits and trade-offs associated with ethanol blending in biodiesel-based diesel fuels that are compatible with existing diesel vehicles.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"25 ","pages":"Article 100461"},"PeriodicalIF":5.0,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-08DOI: 10.1016/j.jaecs.2025.100454
Nicholas Rock , Mateo Gomez , Aaron W. Skiba
Detonation-based technologies have been developed primarily by evaluating different design concepts using global performance metrics (e.g., wave speeds and thrust output). However, several technical challenges, which may require a physics-based development approach to mitigate or resolve, continue to hinder these systems. Unfortunately, the most commonly used tools for characterizing the physics of detonations (i.e., cell size measurements, empirical correlations, and predictive models) do not typically provide enough detailed information to make a significant impact on the development of detonation-based technologies. Therefore, this study demonstrates the use of planar laser Rayleigh scattering (PLRS) imaging to acquire highly resolved data from ethylene-air detonations produced at atmospheric conditions. In particular, the PLRS images enable rare measurements of induction zone regions and allow the details of a detonation’s underlying structure to be visualized in great detail. The accuracy of the induction zone length measurements is assessed via a systematic numerical analysis involving the simulation of laser Rayleigh scattering (LRS) signals from one-dimensional (1-D) ZND results. The numerical results were quantitatively compared to measured LRS signal levels, their spatial gradients, and induction zone lengths at local wave speeds estimated from high-speed (MHz) chemiluminescence imaging. Varying levels of agreement between the measured and calculated results are observed, with the best agreement achieved for detonations propagating at or faster than the CJ speed. Beyond the measured results, this manuscript clearly highlights the benefits, challenges, and future potential of applying PLRS imaging to detonations.
{"title":"On the application of planar laser Rayleigh scattering imaging to Ethylene-air detonations at normal atmospheric conditions","authors":"Nicholas Rock , Mateo Gomez , Aaron W. Skiba","doi":"10.1016/j.jaecs.2025.100454","DOIUrl":"10.1016/j.jaecs.2025.100454","url":null,"abstract":"<div><div>Detonation-based technologies have been developed primarily by evaluating different design concepts using global performance metrics (e.g., wave speeds and thrust output). However, several technical challenges, which may require a physics-based development approach to mitigate or resolve, continue to hinder these systems. Unfortunately, the most commonly used tools for characterizing the physics of detonations (i.e., cell size measurements, empirical correlations, and predictive models) do not typically provide enough detailed information to make a significant impact on the development of detonation-based technologies. Therefore, this study demonstrates the use of planar laser Rayleigh scattering (PLRS) imaging to acquire highly resolved data from ethylene-air detonations produced at atmospheric conditions. In particular, the PLRS images enable rare measurements of induction zone regions and allow the details of a detonation’s underlying structure to be visualized in great detail. The accuracy of the induction zone length measurements is assessed via a systematic numerical analysis involving the simulation of laser Rayleigh scattering (LRS) signals from one-dimensional (1-D) ZND results. The numerical results were quantitatively compared to measured LRS signal levels, their spatial gradients, and induction zone lengths at local wave speeds estimated from high-speed (MHz) chemiluminescence imaging. Varying levels of agreement between the measured and calculated results are observed, with the best agreement achieved for detonations propagating at or faster than the CJ speed. Beyond the measured results, this manuscript clearly highlights the benefits, challenges, and future potential of applying PLRS imaging to detonations.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"25 ","pages":"Article 100454"},"PeriodicalIF":5.0,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-08DOI: 10.1016/j.jaecs.2026.100460
Pourya Rahnama , Ricardo Novella , Bart Somers
This study combines a 0D Well Stirred Reactor (WSR), 1D counterflow flame, experimental data, and a 1D gas dynamic model to create an integrated modeling tool to study the dual fuel combustion behavior in engine-relevant conditions, fueled with E85 and diesel fuels. First, the performance of a reduced chemical kinetic mechanism is studied, and the most important reactions are identified. Subsequently, the validated mechanism is utilized to investigate ignition and flame propagation characteristics, and to analyze the combustion mode in different thermal and compositional stratification levels. The results reveal that under the studied operating conditions, auto-ignition of the background mixture was unlikely due to long ignition delay times compared to experimental combustion durations. Instead, the combustion mode is more of a partially premixed flame and diffusive combustion influenced by reactivity and thermal stratification. The effects of thermal stratification revealed that at higher temperatures of the background mixture, the location of the most reactive mixture fractions moves to the richer sides. Notably, low-temperature ignition behavior reflects the existence of cool flame chemistry near the stoichiometric zone, where intermediate species like formaldehyde form before full heat release occurs. When the oxidizer temperature increases further, a secondary, most reactive mixture fraction can be observed on the oxidizer (lean) side. Temperature and heat release rate profiles also revealed that at lower oxidizer temperatures, the heat release rate shows more traditional diffusive combustion behavior. However, at elevated temperatures, the secondary heat release rate, which corresponds to flame propagation, becomes more prominent. Increasing the ratio of E85 to diesel also influences the partially premixed flame propagation and its heat release. When the oxidizer temperature or E85 content is increased, the location of the secondary heat release moves further away to the oxidizer side, away from the stoichiometric region.
{"title":"A modeling study on the combustion characteristics of alcohol/diesel dual fuel counterflow flame","authors":"Pourya Rahnama , Ricardo Novella , Bart Somers","doi":"10.1016/j.jaecs.2026.100460","DOIUrl":"10.1016/j.jaecs.2026.100460","url":null,"abstract":"<div><div>This study combines a 0D Well Stirred Reactor (WSR), 1D counterflow flame, experimental data, and a 1D gas dynamic model to create an integrated modeling tool to study the dual fuel combustion behavior in engine-relevant conditions, fueled with E85 and diesel fuels. First, the performance of a reduced chemical kinetic mechanism is studied, and the most important reactions are identified. Subsequently, the validated mechanism is utilized to investigate ignition and flame propagation characteristics, and to analyze the combustion mode in different thermal and compositional stratification levels. The results reveal that under the studied operating conditions, auto-ignition of the background mixture was unlikely due to long ignition delay times compared to experimental combustion durations. Instead, the combustion mode is more of a partially premixed flame and diffusive combustion influenced by reactivity and thermal stratification. The effects of thermal stratification revealed that at higher temperatures of the background mixture, the location of the most reactive mixture fractions moves to the richer sides. Notably, low-temperature ignition behavior reflects the existence of cool flame chemistry near the stoichiometric zone, where intermediate species like formaldehyde form before full heat release occurs. When the oxidizer temperature increases further, a secondary, most reactive mixture fraction can be observed on the oxidizer (lean) side. Temperature and heat release rate profiles also revealed that at lower oxidizer temperatures, the heat release rate shows more traditional diffusive combustion behavior. However, at elevated temperatures, the secondary heat release rate, which corresponds to flame propagation, becomes more prominent. Increasing the ratio of E85 to diesel also influences the partially premixed flame propagation and its heat release. When the oxidizer temperature or E85 content is increased, the location of the secondary heat release moves further away to the oxidizer side, away from the stoichiometric region.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"25 ","pages":"Article 100460"},"PeriodicalIF":5.0,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-08DOI: 10.1016/j.jaecs.2026.100459
Jikang Wang , Yichen Wang, Yupeng Qin, Xuan Lv
This paper compares two data-driven frameworks for monitoring thermoacoustic instability (TAI) in a gas turbine combustor. A conventional machine learning approach using handcrafted features is contrasted with an end-to-end deep learning method employing a convolutional autoencoder (CNN-AE). Both frameworks generate a continuous stability index to quantify the transition from stable to unstable states. Using experimental data, both indices successfully track the entire dynamic evolution, including intermittent precursors. Critically, the CNN-AE autonomously learns a physically meaningful latent space. Visualizing this space reveals the system’s trajectory, showing a clear transition from a disordered attractor (combustion noise) to well-defined limit cycles (instability) through distinct topological shifts. The study demonstrates that deep representation learning not only automates monitoring but also provides a powerful tool for uncovering the underlying nonlinear dynamics of TAI.
{"title":"Monitoring thermoacoustic instability: A comparative analysis of feature-based and end-to-end deep learning approaches","authors":"Jikang Wang , Yichen Wang, Yupeng Qin, Xuan Lv","doi":"10.1016/j.jaecs.2026.100459","DOIUrl":"10.1016/j.jaecs.2026.100459","url":null,"abstract":"<div><div>This paper compares two data-driven frameworks for monitoring thermoacoustic instability (TAI) in a gas turbine combustor. A conventional machine learning approach using handcrafted features is contrasted with an end-to-end deep learning method employing a convolutional autoencoder (CNN-AE). Both frameworks generate a continuous stability index to quantify the transition from stable to unstable states. Using experimental data, both indices successfully track the entire dynamic evolution, including intermittent precursors. Critically, the CNN-AE autonomously learns a physically meaningful latent space. Visualizing this space reveals the system’s trajectory, showing a clear transition from a disordered attractor (combustion noise) to well-defined limit cycles (instability) through distinct topological shifts. The study demonstrates that deep representation learning not only automates monitoring but also provides a powerful tool for uncovering the underlying nonlinear dynamics of TAI.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"25 ","pages":"Article 100459"},"PeriodicalIF":5.0,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-05DOI: 10.1016/j.jaecs.2026.100458
Mingyu Li , Ruixiao Li , Vladimir Zarko , Richard A. Yetter , Zhongyue Zhou , Weiqiang Pang
Nano-sized boron (nB)-based composite energetic materials (CEMs) are an emerging class of high-energy-density fuels with excellent combustion performance, offering broad potential applications in space propulsion and explosives. In this paper, we review the various preparation techniques for nB-based CEMs (comparing their respective advantages and limitations) and discuss the combustion characteristics and reaction mechanisms of these materials, while also surveying current development trends and future challenges. Recent findings show that incorporating nB significantly improves the ignition characteristics, burning rates, and overall energy release efficiency of B-based energetic formulations. In particular, nB-based composites exhibit faster reaction kinetics, higher energy release rates, and greater gas generation than their micro-sized boron (μB) counterparts. These enhancements underscore the promise of nB-based CEMs for next-generation propellants, explosives, and pyrotechnics, and existing research has already laid a solid foundation for further progress in designing such advanced energetic systems.
{"title":"Nano-sized boron composites energetic materials: Preparation, combustion and mechanism","authors":"Mingyu Li , Ruixiao Li , Vladimir Zarko , Richard A. Yetter , Zhongyue Zhou , Weiqiang Pang","doi":"10.1016/j.jaecs.2026.100458","DOIUrl":"10.1016/j.jaecs.2026.100458","url":null,"abstract":"<div><div>Nano-sized boron (nB)-based composite energetic materials (CEMs) are an emerging class of high-energy-density fuels with excellent combustion performance, offering broad potential applications in space propulsion and explosives. In this paper, we review the various preparation techniques for nB-based CEMs (comparing their respective advantages and limitations) and discuss the combustion characteristics and reaction mechanisms of these materials, while also surveying current development trends and future challenges. Recent findings show that incorporating nB significantly improves the ignition characteristics, burning rates, and overall energy release efficiency of B-based energetic formulations. In particular, nB-based composites exhibit faster reaction kinetics, higher energy release rates, and greater gas generation than their micro-sized boron (μB) counterparts. These enhancements underscore the promise of nB-based CEMs for next-generation propellants, explosives, and pyrotechnics, and existing research has already laid a solid foundation for further progress in designing such advanced energetic systems.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"25 ","pages":"Article 100458"},"PeriodicalIF":5.0,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.jaecs.2026.100457
Márton Kovács , Kaito Hirose , Koji Shimoyama , Hisashi Nakamura
A methodology is presented to develop compact, high-fidelity simplified reaction models for hydrocarbon combustion using virtual species and simplified reaction pathways, with rate parameters optimized via a genetic algorithm (GA). The method was applied to methane and natural gas combustion, targeting key combustion properties: ignition delay times (IDT) and laminar burning velocities (LBV). The approach combines a detailed H2/CO core with virtual reactions representing the main fuel oxidation pathways through fuel, fuel radical, and aldehyde virtual species. For natural gas, fuel components were lumped, and averaged thermodynamic properties were assigned to the virtual species. The optimization process produced simplified models with 14 species and 57 reactions, which could accurately reproduce the IDT and LBV simulation results of the AramcoMech 3.0 detailed model across a wide range of equivalence ratios and temperatures. The mean absolute deviations for all test conditions were 11.9% for IDT and 2.5% for LBV in methane, and 10.5% for IDT and 1.4% for LBV in natural gas simulations. The models could capture the tendency differences between methane/air and natural gas/air mixtures in ignition characteristics while preserving the similarities in flame propagation. The proposed method offers a practical alternative to conventional reduction techniques, enabling the generation of simple yet accurate reaction models suitable for CFD simulations in practical combustors with significantly reduced computational cost.
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The rapid growth of municipal solid waste (MSW) has posed severe environmental challenges, making its safe and resource-efficient disposal crucial for urban sustainable development. Gasification technology offers a promising route for the high-value utilization of MSW by converting it into hydrogen-rich syngas that can be used for power generation, heating, or the production of high-purity H2 fuels. However, the heterogeneous and variable composition of MSW complicates gasification, while the coupled effects of operating parameters on H2 formation remain insufficiently understood. Moreover, a systematic understanding that integrates feedstock characteristics, process optimization, and emerging gasification technologies for efficient H2 generation is still lacking. Therefore, this review systematically summarizes the fundamental characteristics of MSW, the pyrolysis and gasification behaviors of MSW and products characteristics. Key process parameters affecting hydrogen production, including gasifying agents, reaction temperature, residence time, and catalyst type, are critically analyzed. In addition, recent advances in novel heating-assisted gasification technologies, including plasma, Joule heating, electromagnetic induction heating, and microwave heating, are reviewed, together with novel processes such as chemical looping gasification. Finally, large-scale industrial applications of MSW gasification and the recent syngas purification methods for pure H2 production are summarized, followed by an outlook on the future development trends and research priorities for MSW gasification toward sustainable hydrogen production. This review is expected to provide valuable guidance for the process optimization, development of novel gasification technologies, and engineering application of MSW gasification technology for hydrogen production.
{"title":"A review of municipal solid waste gasification for hydrogen production: Influencing factors, novel technologies, and engineering prospects","authors":"Yongfeng Jiang , Zixuan Yuan , Hao Jiang, Hao Song, Qiang Hu, Jiageng Xia, Haiping Yang, Hanping Chen","doi":"10.1016/j.jaecs.2026.100456","DOIUrl":"10.1016/j.jaecs.2026.100456","url":null,"abstract":"<div><div>The rapid growth of municipal solid waste (MSW) has posed severe environmental challenges, making its safe and resource-efficient disposal crucial for urban sustainable development. Gasification technology offers a promising route for the high-value utilization of MSW by converting it into hydrogen-rich syngas that can be used for power generation, heating, or the production of high-purity H<sub>2</sub> fuels. However, the heterogeneous and variable composition of MSW complicates gasification, while the coupled effects of operating parameters on H<sub>2</sub> formation remain insufficiently understood. Moreover, a systematic understanding that integrates feedstock characteristics, process optimization, and emerging gasification technologies for efficient H<sub>2</sub> generation is still lacking. Therefore, this review systematically summarizes the fundamental characteristics of MSW, the pyrolysis and gasification behaviors of MSW and products characteristics. Key process parameters affecting hydrogen production, including gasifying agents, reaction temperature, residence time, and catalyst type, are critically analyzed. In addition, recent advances in novel heating-assisted gasification technologies, including plasma, Joule heating, electromagnetic induction heating, and microwave heating, are reviewed, together with novel processes such as chemical looping gasification. Finally, large-scale industrial applications of MSW gasification and the recent syngas purification methods for pure H<sub>2</sub> production are summarized, followed by an outlook on the future development trends and research priorities for MSW gasification toward sustainable hydrogen production. This review is expected to provide valuable guidance for the process optimization, development of novel gasification technologies, and engineering application of MSW gasification technology for hydrogen production.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"25 ","pages":"Article 100456"},"PeriodicalIF":5.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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