Pub Date : 2025-01-16DOI: 10.1016/j.pecs.2025.101220
Linhao Fan , Jiaqi Wang , Daniela Fernanda Ruiz Diaz , Lincai Li , Yun Wang , Kui Jiao
Catalyst layers (CLs) are a key component of proton exchange membrane (PEM) fuel cells, where electrochemical reactions occur. The future development of catalysts, catalyst supports, ionomer electrolytes, and CL architectures, along with their preparation, is of great importance for achieving high-performance and low-cost PEM fuel cells. Developing novel CLs involves complex multi-parameter optimization, posing significant challenges for time-consuming experiments. Due to CL's nanoscale structures, molecular dynamics (MD) simulation is an appropriate method to investigate transport and structural characteristics in CLs, playing an crucial role in CL development. This review aims at the fundamentals of MD simulations, overview of MD simulations in CL applications, latest developments of catalysts, catalyst support, ionomer materials, CL architectures, and roles of MD in CL development, as well as associated challenges and prospects. This review is invaluable for guiding researchers in understanding the mechanisms of transport and structural evolution mechanisms in CLs and developing novel CLs through MD modeling.
{"title":"Molecular dynamics modeling in catalyst layer development for PEM fuel cell","authors":"Linhao Fan , Jiaqi Wang , Daniela Fernanda Ruiz Diaz , Lincai Li , Yun Wang , Kui Jiao","doi":"10.1016/j.pecs.2025.101220","DOIUrl":"10.1016/j.pecs.2025.101220","url":null,"abstract":"<div><div>Catalyst layers (CLs) are a key component of proton exchange membrane (PEM) fuel cells, where electrochemical reactions occur. The future development of catalysts, catalyst supports, ionomer electrolytes, and CL architectures, along with their preparation, is of great importance for achieving high-performance and low-cost PEM fuel cells. Developing novel CLs involves complex multi-parameter optimization, posing significant challenges for time-consuming experiments. Due to CL's nanoscale structures, molecular dynamics (MD) simulation is an appropriate method to investigate transport and structural characteristics in CLs, playing an crucial role in CL development. This review aims at the fundamentals of MD simulations, overview of MD simulations in CL applications, latest developments of catalysts, catalyst support, ionomer materials, CL architectures, and roles of MD in CL development, as well as associated challenges and prospects. This review is invaluable for guiding researchers in understanding the mechanisms of transport and structural evolution mechanisms in CLs and developing novel CLs through MD modeling.</div></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"108 ","pages":"Article 101220"},"PeriodicalIF":32.0,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143097630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.pecs.2024.101202
Jennifer X. Wen , Ethan S. Hecht , Remy Mevel
Hydrogen is a key pillar in the global Net Zero strategy. Rapid scaling up of hydrogen production, transport, distribution and utilization is expected. This entails that hydrogen, which is traditionally an industrial gas, will come into proximity of populated urban areas and in some situations handled by the untrained public. To realize all their benefits, hydrogen and its technologies must be safely developed and deployed. The specific properties of hydrogen involving wide flammability range, low ignition energy and fast flame speed implies that any accidental release of hydrogen can be easily ignited. Comparing with conventional fuels, combustion systems fueled by hydrogen are also more prone to flame instability and abnormal combustion. This paper aims to provide a comprehensive review about combustion research related to hydrogen safety. It starts with a brief introduction which includes some overview about risk analysis, codes and standards. The core content covers ignition, fire, explosions and deflagration to detonation transition (DDT). Considering that DDT leads to detonation, and that detonation may also be induced directly under special circumstances, the subject of detonation is also included for completeness. The review covers laboratory, medium and large-scale experiments, as well as theoretical analysis and numerical simulation results. While highlights are provided at the end of each section, the paper closes with some concluding remarks highlighting the achievements and key knowledge gaps.
{"title":"Recent advances in combustion science related to hydrogen safety","authors":"Jennifer X. Wen , Ethan S. Hecht , Remy Mevel","doi":"10.1016/j.pecs.2024.101202","DOIUrl":"10.1016/j.pecs.2024.101202","url":null,"abstract":"<div><div>Hydrogen is a key pillar in the global Net Zero strategy. Rapid scaling up of hydrogen production, transport, distribution and utilization is expected. This entails that hydrogen, which is traditionally an industrial gas, will come into proximity of populated urban areas and in some situations handled by the untrained public. To realize all their benefits, hydrogen and its technologies must be safely developed and deployed. The specific properties of hydrogen involving wide flammability range, low ignition energy and fast flame speed implies that any accidental release of hydrogen can be easily ignited. Comparing with conventional fuels, combustion systems fueled by hydrogen are also more prone to flame instability and abnormal combustion. This paper aims to provide a comprehensive review about combustion research related to hydrogen safety. It starts with a brief introduction which includes some overview about risk analysis, codes and standards. The core content covers ignition, fire, explosions and deflagration to detonation transition (DDT). Considering that DDT leads to detonation, and that detonation may also be induced directly under special circumstances, the subject of detonation is also included for completeness. The review covers laboratory, medium and large-scale experiments, as well as theoretical analysis and numerical simulation results. While highlights are provided at the end of each section, the paper closes with some concluding remarks highlighting the achievements and key knowledge gaps.</div></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"107 ","pages":"Article 101202"},"PeriodicalIF":32.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-05DOI: 10.1016/j.pecs.2024.101201
Christos N. Markides , André Bardow , Michel De Paepe , Carlo De Servi , Joachim Groß , Andrew J. Haslam , Steven Lecompte , Athanasios I. Papadopoulos , Oyeniyi A. Oyewunmi , Panos Seferlis , Johannes Schilling , Patrick Linke , Hua Tian , Gequn Shu
Organic Rankine cycle (ORC) systems are a class of distributed power-generation systems that are suitable for the efficient conversion of low-to-medium temperature thermal energy to useful power. These versatile systems have significant potential to contribute in diverse ways to future clean and sustainable energy systems through, e.g., deployment for waste-heat recovery in industrial facilities, but also the utilisation of renewable-heat sources, thereby improving energy access and living standards, while reducing primary energy consumption and the associated emissions. The energetic and economic performance, but also environmental sustainability of ORC systems, all depend strongly on the working fluid employed, and therefore a significant effort has been made in recent years to select, but also to design novel working fluids for ORC systems. In this context, computer-aided molecular design (CAMD) techniques have emerged as highly promising approaches with which to explore the key role of working fluids, and present an opportunity, by focusing on the design of new eco-friendly fluids with low environmental footprints, to identify alternatives to traditional refrigerants with improved characteristics. In this review article, an overview of working-fluid and system optimisation methodologies that can be used for the design and operation of next-generation ORC systems is provided. With reference to wide-ranging applications from waste-heat recovery in industrial and automotive applications, to biomass, geothermal and solar-energy conversion and/or storage, this review represents a comprehensive, forward-looking exposition of the application of CAMD to the design of ORC technology.
{"title":"Working fluid and system optimisation of organic Rankine cycles via computer-aided molecular design: A review","authors":"Christos N. Markides , André Bardow , Michel De Paepe , Carlo De Servi , Joachim Groß , Andrew J. Haslam , Steven Lecompte , Athanasios I. Papadopoulos , Oyeniyi A. Oyewunmi , Panos Seferlis , Johannes Schilling , Patrick Linke , Hua Tian , Gequn Shu","doi":"10.1016/j.pecs.2024.101201","DOIUrl":"10.1016/j.pecs.2024.101201","url":null,"abstract":"<div><div>Organic Rankine cycle (ORC) systems are a class of distributed power-generation systems that are suitable for the efficient conversion of low-to-medium temperature thermal energy to useful power. These versatile systems have significant potential to contribute in diverse ways to future clean and sustainable energy systems through, <em>e.g.</em>, deployment for waste-heat recovery in industrial facilities, but also the utilisation of renewable-heat sources, thereby improving energy access and living standards, while reducing primary energy consumption and the associated emissions. The energetic and economic performance, but also environmental sustainability of ORC systems, all depend strongly on the working fluid employed, and therefore a significant effort has been made in recent years to select, but also to design novel working fluids for ORC systems. In this context, computer-aided molecular design (CAMD) techniques have emerged as highly promising approaches with which to explore the key role of working fluids, and present an opportunity, by focusing on the design of new eco-friendly fluids with low environmental footprints, to identify alternatives to traditional refrigerants with improved characteristics. In this review article, an overview of working-fluid and system optimisation methodologies that can be used for the design and operation of next-generation ORC systems is provided. With reference to wide-ranging applications from waste-heat recovery in industrial and automotive applications, to biomass, geothermal and solar-energy conversion and/or storage, this review represents a comprehensive, forward-looking exposition of the application of CAMD to the design of ORC technology.</div></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"107 ","pages":"Article 101201"},"PeriodicalIF":32.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.pecs.2024.101200
S. Posch , C. Gößnitzer , M. Lang , R. Novella , H. Steiner , A. Wimmer
The modeling of combustion or, to be exact, turbulent combustion using numerical simulation has become state-of-the-art in the process of developing internal combustion engines (ICE). Since the combustion regimes that occur fundamentally differ depending on the combustion concept used, several turbulent combustion models have been developed to meet the respective requirements. The selection of appropriate combustion models is crucial to accurately reflect the physical processes, specifically considering the mixing conditions and the effects of turbulence on the mean reaction rate. This review provides an overview of turbulent combustion models for use in ICE computational fluid dynamics. After a brief introduction to the basic aspects of ICE combustion simulation, the underlying governing equations and the required physical background are outlined. Next, the relevant turbulent combustion models for ICE application and their mathematical formulations are aggregated to enable the discussion of relevant model parameters and characteristics. A comprehensive review of application cases with respect to ICE technologies, namely spark ignition and compression ignition, is given. Furthermore, recent advances and future prospects in terms of the integration of future fuels, the enhancement of turbulent combustion models to meet future engine technologies and the use of machine learning techniques to advance turbulent combustion simulation in the context of ICE are discussed.
{"title":"Turbulent combustion modeling for internal combustion engine CFD: A review","authors":"S. Posch , C. Gößnitzer , M. Lang , R. Novella , H. Steiner , A. Wimmer","doi":"10.1016/j.pecs.2024.101200","DOIUrl":"10.1016/j.pecs.2024.101200","url":null,"abstract":"<div><div>The modeling of combustion or, to be exact, turbulent combustion using numerical simulation has become state-of-the-art in the process of developing internal combustion engines (ICE). Since the combustion regimes that occur fundamentally differ depending on the combustion concept used, several turbulent combustion models have been developed to meet the respective requirements. The selection of appropriate combustion models is crucial to accurately reflect the physical processes, specifically considering the mixing conditions and the effects of turbulence on the mean reaction rate. This review provides an overview of turbulent combustion models for use in ICE computational fluid dynamics. After a brief introduction to the basic aspects of ICE combustion simulation, the underlying governing equations and the required physical background are outlined. Next, the relevant turbulent combustion models for ICE application and their mathematical formulations are aggregated to enable the discussion of relevant model parameters and characteristics. A comprehensive review of application cases with respect to ICE technologies, namely spark ignition and compression ignition, is given. Furthermore, recent advances and future prospects in terms of the integration of future fuels, the enhancement of turbulent combustion models to meet future engine technologies and the use of machine learning techniques to advance turbulent combustion simulation in the context of ICE are discussed.</div></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"106 ","pages":"Article 101200"},"PeriodicalIF":32.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142592771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.pecs.2024.101199
Tina Kegl , Eloísa Torres Jiménez , Breda Kegl , Anita Kovač Kralj , Marko Kegl
Anaerobic digestion (AD) is an important technology that can be engaged to produce renewable energy and valuable products from organic waste while reducing the net greenhouse gas emissions. Due to the AD process complexity, further development of AD technology goes hand in hand with the advancement of underlying mathematical models and optimization techniques. This paper presents a comprehensive and critical review of current AD process modeling and optimization techniques as well as various aspects of further processing of AD products. The most important mechanistically inspired, kinetic, and phenomenological AD models and the most frequently used deterministic and stochastic methods for AD process optimization are addressed. The foundations, properties, and features of these models and methods are highlighted, discussed, and compared with respect to advantages, disadvantages, and various performance metrics; the models are also ranked with respect to adequately introduced criteria. Since AD process optimization affects heavily the required treatment and utilization of AD products, biogas and digestate utilization in the production of renewable energy and other valuable products is also addressed. Furthermore, special attention is devoted to the challenges and future research needs related to AD modeling and optimization, such are modeling issues related to foaming and microbial activities, AD model parameters calibration, CFD simulation challenges, availability of experimental data, and optimization of the AD process with respect to further biogas and digestate utilizations. As current research results indicate, further progress in these areas could notably improve AD modeling robustness and accuracy as well as AD optimization performance.
{"title":"Modeling and optimization of anaerobic digestion technology: Current status and future outlook","authors":"Tina Kegl , Eloísa Torres Jiménez , Breda Kegl , Anita Kovač Kralj , Marko Kegl","doi":"10.1016/j.pecs.2024.101199","DOIUrl":"10.1016/j.pecs.2024.101199","url":null,"abstract":"<div><div>Anaerobic digestion (AD) is an important technology that can be engaged to produce renewable energy and valuable products from organic waste while reducing the net greenhouse gas emissions. Due to the AD process complexity, further development of AD technology goes hand in hand with the advancement of underlying mathematical models and optimization techniques. This paper presents a comprehensive and critical review of current AD process modeling and optimization techniques as well as various aspects of further processing of AD products. The most important mechanistically inspired, kinetic, and phenomenological AD models and the most frequently used deterministic and stochastic methods for AD process optimization are addressed. The foundations, properties, and features of these models and methods are highlighted, discussed, and compared with respect to advantages, disadvantages, and various performance metrics; the models are also ranked with respect to adequately introduced criteria. Since AD process optimization affects heavily the required treatment and utilization of AD products, biogas and digestate utilization in the production of renewable energy and other valuable products is also addressed. Furthermore, special attention is devoted to the challenges and future research needs related to AD modeling and optimization, such are modeling issues related to foaming and microbial activities, AD model parameters calibration, CFD simulation challenges, availability of experimental data, and optimization of the AD process with respect to further biogas and digestate utilizations. As current research results indicate, further progress in these areas could notably improve AD modeling robustness and accuracy as well as AD optimization performance.</div></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"106 ","pages":"Article 101199"},"PeriodicalIF":32.0,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermochemical energy storage (TCES) based on calcium-looping (CaL) has great potential to mitigate the intermittency and instability problems of solar energy harvesting, especially for high-temperature solar thermal utilization. The CaCO3/CaO TCES system has been the focus of intense research over the past few decades for its advantages of high energy storage density, natural abundance of raw materials, low cost, and environmentally benign nature, simultaneously. Although some properties of the CaCO3/CaO TCES system have been concluded, few of them consider the relationships between structures and performances at multiple time and length scales. Herein, we summarize the multiscale developments of the CaCO3/CaO-based TCES systematically, including atomic-scale mechanisms, reaction thermodynamics, cyclic stabilities, energy storage/release properties in reactors, operations, and efficiency optimizations at a system level. This review aims to broaden research interests in multiscale structure-function relationships in the field of TCES and provide constructive references for exploring advanced methods and mature technologies for material development, reactor upgradation, and system optimization. Finally, it will promote the large-scale industrial applications of calcium-looping for thermochemical energy storage.
{"title":"Progress in multiscale research on calcium-looping for thermochemical energy storage: From materials to systems","authors":"Xikun Tian, Sijia Guo, Xiaojun Lv, Shangchao Lin, Chang-Ying Zhao","doi":"10.1016/j.pecs.2024.101194","DOIUrl":"10.1016/j.pecs.2024.101194","url":null,"abstract":"<div><div>Thermochemical energy storage (TCES) based on calcium-looping (CaL) has great potential to mitigate the intermittency and instability problems of solar energy harvesting, especially for high-temperature solar thermal utilization. The CaCO<sub>3</sub>/CaO TCES system has been the focus of intense research over the past few decades for its advantages of high energy storage density, natural abundance of raw materials, low cost, and environmentally benign nature, simultaneously. Although some properties of the CaCO<sub>3</sub>/CaO TCES system have been concluded, few of them consider the relationships between structures and performances at multiple time and length scales. Herein, we summarize the multiscale developments of the CaCO<sub>3</sub>/CaO-based TCES systematically, including atomic-scale mechanisms, reaction thermodynamics, cyclic stabilities, energy storage/release properties in reactors, operations, and efficiency optimizations at a system level. This review aims to broaden research interests in multiscale structure-function relationships in the field of TCES and provide constructive references for exploring advanced methods and mature technologies for material development, reactor upgradation, and system optimization. Finally, it will promote the large-scale industrial applications of calcium-looping for thermochemical energy storage.</div></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"106 ","pages":"Article 101194"},"PeriodicalIF":32.0,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1016/j.pecs.2024.101193
Meng Zhang , Xutao Wei , Zhenhua An , Ekenechukwu C. Okafor , Thibault F. Guiberti , Jinhua Wang , Zuohua Huang
Global climate change forces all countries to push the process of de-carbonization. Ammonia, which is carbon free and a potential hydrogen carrier, is proposed as a prospective fuel for the power devices to realize the green economy. It also exhibits very good fuel properties, including its storage condition, energy density. However, two main challenges, the difficulties of flame stabilization and potential high fuel NOx production, still need to be tackled in its application in gas turbines. In the last decades, valuable investigations were conducted to address characteristics of NH3/air flame stabilization in swirl combustors as well as the combustion enhancement by cofiring with active molecule like CH4 and H2, applying plasma assistance. These measures mainly improve the flame resistance to the flow and increase the key radicals at flame base, which may provide possible solutions to the combustion chamber design. The inherent mechanisms of fuel NOx production are highlighted by the HNO channel with the presence of OH radical. One promising strategy to mitigate NOx in gas-turbine like combustor is the staged combustion by staging the air or fuel, which may also fit for the practical combustion chamber. The high-pressure condition and plasma assistance were found to show positive influence on both flame stabilization and NOx control. This review also emphasizes the fundamental research issues for ammonia fuel and proposes some future research prospects towards the development of more robust, reliable, and low NOx combustion technologies relevant to gas turbines.
{"title":"Flame stabilization and emission characteristics of ammonia combustion in lab-scale gas turbine combustors: Recent progress and prospects","authors":"Meng Zhang , Xutao Wei , Zhenhua An , Ekenechukwu C. Okafor , Thibault F. Guiberti , Jinhua Wang , Zuohua Huang","doi":"10.1016/j.pecs.2024.101193","DOIUrl":"10.1016/j.pecs.2024.101193","url":null,"abstract":"<div><div>Global climate change forces all countries to push the process of de-carbonization. Ammonia, which is carbon free and a potential hydrogen carrier, is proposed as a prospective fuel for the power devices to realize the green economy. It also exhibits very good fuel properties, including its storage condition, energy density. However, two main challenges, the difficulties of flame stabilization and potential high fuel NO<sub>x</sub> production, still need to be tackled in its application in gas turbines. In the last decades, valuable investigations were conducted to address characteristics of NH<sub>3</sub>/air flame stabilization in swirl combustors as well as the combustion enhancement by cofiring with active molecule like CH<sub>4</sub> and H<sub>2</sub>, applying plasma assistance. These measures mainly improve the flame resistance to the flow and increase the key radicals at flame base, which may provide possible solutions to the combustion chamber design. The inherent mechanisms of fuel NO<sub>x</sub> production are highlighted by the HNO channel with the presence of OH radical. One promising strategy to mitigate NO<sub>x</sub> in gas-turbine like combustor is the staged combustion by staging the air or fuel, which may also fit for the practical combustion chamber. The high-pressure condition and plasma assistance were found to show positive influence on both flame stabilization and NO<sub>x</sub> control. This review also emphasizes the fundamental research issues for ammonia fuel and proposes some future research prospects towards the development of more robust, reliable, and low NO<sub>x</sub> combustion technologies relevant to gas turbines.</div></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"106 ","pages":"Article 101193"},"PeriodicalIF":32.0,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-27DOI: 10.1016/j.pecs.2024.101198
A S M Sazzad Parveg, Albert Ratner
Nanofuels (NFs) are an innovative fuel category where nano-scale metal or carbon-based particles are suspended within liquid fuel (LF) to enhance performance, combustion efficiency, and emission characteristics of internal combustion devices while preserving the base fuel properties. Carbon-nanoparticle-based nanofuels (CNFs) have recently attracted attention for their potential to significantly enhance combustion performance and reduce emissions. CNFs offer advantages such as lower toxicity, a reduced environmental footprint, and cost-effectiveness compared to metal-based alternatives. Carbon nanoparticles exhibit potential in enhancing liquid fuel combustion characteristics, particularly when used at low particle concentrations (≤0.30 % w/w), which is likely to be optimal for improving the burning rate. This enhancement can be attributed to their superior heat absorption and transfer properties, improved atomization mechanisms, and impact on combustion kinetics. This review investigates the potential of CNFs and examines the mechanisms by which they alter combustion and evaporation characteristics. Empirical evidence indicates that the increased evaporation and burning rates of CNFs are primarily due to improved radiation capture and heat transfer. The behavior of ignition is closely related to the aggregation and distribution of nanoparticles within CNF droplets, which affects fuel evaporation dynamics. Additionally, increased micro-explosion intensity and generally reduced micro-explosion frequency are observed during CNF droplet combustion. Factors such as particle size, concentration, morphology, and thermo-physical properties play crucial roles in influencing changes in evaporation rate, burning rate, ignition delay, burning period, and micro-explosion characteristics. Studies conducted at droplet, spray, and engine scales consistently support the positive effects of CNFs observed at the droplet scale. These improvements lead to enhanced combustion parameters, better engine performance and a significant reduction in harmful emissions. However, concerns remain about the potential presence of nanoparticles in exhaust emissions and their implications for the environment and human health. This review offers a comprehensive analysis of CNFs, providing insights into their potential applications and identifying areas that require further research.
{"title":"A comprehensive review of liquid fuel droplet evaporation and combustion behavior with carbon-based nanoparticles","authors":"A S M Sazzad Parveg, Albert Ratner","doi":"10.1016/j.pecs.2024.101198","DOIUrl":"10.1016/j.pecs.2024.101198","url":null,"abstract":"<div><div>Nanofuels (NFs) are an innovative fuel category where nano-scale metal or carbon-based particles are suspended within liquid fuel (LF) to enhance performance, combustion efficiency, and emission characteristics of internal combustion devices while preserving the base fuel properties. Carbon-nanoparticle-based nanofuels (CNFs) have recently attracted attention for their potential to significantly enhance combustion performance and reduce emissions. CNFs offer advantages such as lower toxicity, a reduced environmental footprint, and cost-effectiveness compared to metal-based alternatives. Carbon nanoparticles exhibit potential in enhancing liquid fuel combustion characteristics, particularly when used at low particle concentrations (≤0.30 % w/w), which is likely to be optimal for improving the burning rate. This enhancement can be attributed to their superior heat absorption and transfer properties, improved atomization mechanisms, and impact on combustion kinetics. This review investigates the potential of CNFs and examines the mechanisms by which they alter combustion and evaporation characteristics. Empirical evidence indicates that the increased evaporation and burning rates of CNFs are primarily due to improved radiation capture and heat transfer. The behavior of ignition is closely related to the aggregation and distribution of nanoparticles within CNF droplets, which affects fuel evaporation dynamics. Additionally, increased micro-explosion intensity and generally reduced micro-explosion frequency are observed during CNF droplet combustion. Factors such as particle size, concentration, morphology, and thermo-physical properties play crucial roles in influencing changes in evaporation rate, burning rate, ignition delay, burning period, and micro-explosion characteristics. Studies conducted at droplet, spray, and engine scales consistently support the positive effects of CNFs observed at the droplet scale. These improvements lead to enhanced combustion parameters, better engine performance and a significant reduction in harmful emissions. However, concerns remain about the potential presence of nanoparticles in exhaust emissions and their implications for the environment and human health. This review offers a comprehensive analysis of CNFs, providing insights into their potential applications and identifying areas that require further research.</div></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"106 ","pages":"Article 101198"},"PeriodicalIF":32.0,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-23DOI: 10.1016/j.pecs.2024.101195
Claire M. Grégoire , Olivier Mathieu , Joseph Kalman , Eric L. Petersen
<div><div>Physical and chemical processes of ammonium perchlorate and hydroxyl-terminated polybutadiene (AP/HTPB) composite propellant combustion have been studied for several decades, and more than 50 years of model development can be reported. Computational methods focus on the heterogeneous aspects—the solid-phase and its decomposition—whereas AP self-deflagration and burning characteristics should be seen as a multi-step, physiochemical process. There has been a lack of systematic studies on the gas-phase chemical kinetics mechanisms for AP combustion, with emphasis on the starting gas-phase species NH<sub>3</sub> and HClO<sub>4</sub>. Only three recent detailed gas-phase mechanisms with sufficient detail in terms of the number of chemical reactions and number of species are currently available in the literature prior to 2023, and simulations are carried out within the present review to assess the state of their current performance and to highlight potential knowledge gaps that should be filled. Given the importance and prevalence of AP in modern propellants, it is surprising that the chemical kinetics of AP combustion are very much understudied. The authors highlight the fact that the few existing AP mechanisms have never been fully vetted against an applicable database of experimental results, certainly not in the manner that mechanisms are typically validated within the combustion science community for fuels such as hydrogen and various hydrocarbons. This review does not put forward such a mechanism, but rather 1) brings to light the limitations of current AP kinetics mechanisms in predicting some limited, available kinetics data, and 2) underlines the need for additional, fundamental data that can be used to calibrate an AP kinetics model. A limited gas-phase experimental database was identified from currently available sources for two main compound families: ammonia (NH<sub>3</sub>) and perchloric acid (HClO<sub>4</sub>). The decomposition of AP is initiated by NH<sub>4</sub>ClO<sub>4</sub> → NH<sub>3</sub> + HClO<sub>4</sub> and leads to these two rather complex molecules that differ strongly in their nature and consequently in their reaction schemes for combustion processes. On the one hand, existing measurements of ignition delay times, laminar flame speeds, and speciation were collected for NH<sub>3</sub>, N<sub>2</sub>O, and NO<sub>2</sub>, and on the other hand, a similar albeit much smaller body of experimental results was assembled for HClO<sub>4</sub>, ClO<sub>2</sub>, and Cl<sub>2</sub>. These global kinetics data were used to evaluate modern AP/HTPB propellant models. We observe that there is much room for improvement regarding models' performance. Significant improvements in our ability to model the gas-phase chemical kinetics of AP combustion can be made by taking advantage of recent developments in ammonia oxidation chemistry modeling. However, additional, fundamental data are needed before similar strengthening of the perc
对高氯酸铵和羟基封端聚丁二烯（AP/HTPB）复合推进剂燃烧的物理和化学过程的研究已有几十年的历史，可报告的模型开发已有 50 多年的历史。计算方法侧重于异质方面--固相及其分解，而 AP 的自燃和燃烧特性应被视为一个多步骤的物理化学过程。目前还缺乏对 AP 燃烧气相化学动力学机制的系统研究，重点是起始气相物种 NH3 和 HClO4。在 2023 年之前的文献中，目前仅有三篇最新的详细气相机制研究，在化学反应数量和物种数量方面都足够详细，本综述对其进行了模拟，以评估其目前的性能状况，并强调应填补的潜在知识空白。鉴于 AP 在现代推进剂中的重要性和普遍性，令人惊讶的是 AP 燃烧的化学动力学研究却非常不足。作者强调了一个事实，即现有的少数 AP 机制从未根据适用的实验结果数据库进行过全面审查，当然也没有像燃烧科学界通常对氢气和各种碳氢化合物等燃料的机制进行验证的方式。这篇综述并没有提出这样的机制，而是：1）揭示了当前 AP 动力学机制在预测一些有限的、可用的动力学数据方面的局限性；2）强调了需要更多可用于校准 AP 动力学模型的基础数据。从目前可获得的资料中，我们确定了两个主要化合物系列的有限气相实验数据库：氨（NH3）和高氯酸（HClO4）。AP 的分解是由 NH4ClO4 → NH3 + HClO4 开始的，这两种相当复杂的分子在性质上有很大不同，因此在燃烧过程中的反应方案也不同。一方面，我们收集了 NH3、N2O 和 NO2 的点火延迟时间、层流火焰速度和标样的现有测量数据；另一方面，我们还收集了 HClO4、ClO2 和 Cl2 的类似实验结果，尽管数量要少得多。这些总体动力学数据被用来评估现代 AP/HTPB 推进剂模型。我们发现，模型的性能还有很大的改进空间。通过利用氨氧化化学建模的最新进展，我们可以显著提高 AP 燃烧气相化学动力学建模的能力。然而，在对与高氯酸盐有关的化学动力学以及涉及 N 和 Cl 物种的跨系统反应进行类似的强化之前，还需要更多的基础数据。
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Pub Date : 2024-08-23DOI: 10.1016/j.pecs.2024.101177
Manuel Monge-Palacios , Xiaoyuan Zhang , Natalia Morlanes , Hisashi Nakamura , Giuseppe Pezzella , S. Mani Sarathy
Ammonia has been essential to human activities for centuries. It is widely used as feedstock for fertilizers, industrial chemicals, and emission after-treatment systems. Owing to its properties, ammonia has garnered interest as a carrier for hydrogen in energy applications. It can be generated from carbon-free emission sources and pyrolyzed to produce pure hydrogen for various applications. The combustion of ammonia for power generation has been previously reviewed in this journal besides several aspects of ammonia oxidation chemistry, as it relates to emission after-treatment and reburn systems. However, the pyrolysis and oxidation chemistry of ammonia requires further elucidation to improve its use as a hydrogen carrier and as a fuel for combustion systems. This article provides an in-depth review of ammonia pyrolysis and oxidation chemistry in noncatalytic and catalytic systems. The catalytic pyrolysis chemistry of ammonia to produce pure hydrogen is reviewed to understand catalyst and reactor requirements for scaling up this technology. The combustion properties of ammonia as a pure fuel and in mixtures, including ignition, flame propagation, and extinction characteristics; its pyrolysis and oxidation reactions; and its potential to produce pollutant emissions are extensively reviewed. Ammonia combustion reaction mechanisms are reported based on results from pyrolysis and oxidation reactors, shock tubes, rapid compression machines, and research engines. The experimental work is complemented by the development of detailed combustion models via chemical kinetic and quantum chemistry simulations. Herein, recent results on ammonia pyrolysis and oxidation chemistry are introduced and summarized by highlighting the pertinent aspects of this rich and rapidly increasing body of information.
{"title":"Ammonia pyrolysis and oxidation chemistry","authors":"Manuel Monge-Palacios , Xiaoyuan Zhang , Natalia Morlanes , Hisashi Nakamura , Giuseppe Pezzella , S. Mani Sarathy","doi":"10.1016/j.pecs.2024.101177","DOIUrl":"10.1016/j.pecs.2024.101177","url":null,"abstract":"<div><p>Ammonia has been essential to human activities for centuries. It is widely used as feedstock for fertilizers, industrial chemicals, and emission after-treatment systems. Owing to its properties, ammonia has garnered interest as a carrier for hydrogen in energy applications. It can be generated from carbon-free emission sources and pyrolyzed to produce pure hydrogen for various applications. The combustion of ammonia for power generation has been previously reviewed in this journal besides several aspects of ammonia oxidation chemistry, as it relates to emission after-treatment and reburn systems. However, the pyrolysis and oxidation chemistry of ammonia requires further elucidation to improve its use as a hydrogen carrier and as a fuel for combustion systems. This article provides an in-depth review of ammonia pyrolysis and oxidation chemistry in noncatalytic and catalytic systems. The catalytic pyrolysis chemistry of ammonia to produce pure hydrogen is reviewed to understand catalyst and reactor requirements for scaling up this technology. The combustion properties of ammonia as a pure fuel and in mixtures, including ignition, flame propagation, and extinction characteristics; its pyrolysis and oxidation reactions; and its potential to produce pollutant emissions are extensively reviewed. Ammonia combustion reaction mechanisms are reported based on results from pyrolysis and oxidation reactors, shock tubes, rapid compression machines, and research engines. The experimental work is complemented by the development of detailed combustion models via chemical kinetic and quantum chemistry simulations. Herein, recent results on ammonia pyrolysis and oxidation chemistry are introduced and summarized by highlighting the pertinent aspects of this rich and rapidly increasing body of information.</p></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"105 ","pages":"Article 101177"},"PeriodicalIF":32.0,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142049668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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