Applications in Energy and Combustion Science最新文献

{"title":"Separation and recovery of biohydrogen using a Pressure Swing Adsorption plant characterized by adsorption of CO2, CO, and CH4: Novel Geometric Control with integral action to mitigate disturbances in a complex process","authors":"Jorge A. Brizuela-Mendoza ,&nbsp;Jesse Y. Rumbo-Morales ,&nbsp;Gerardo Ortiz-Torres ,&nbsp;Felipe D.J. Sorcia-Vázquez ,&nbsp;Jair Gómez Radilla ,&nbsp;Manuela Calixto-Rodriguez ,&nbsp;Estela Sarmiento-Bustos ,&nbsp;Erasmo Misael Rentería Vargas ,&nbsp;Julio César Rodríguez-Cerda ,&nbsp;Jorge Salvador Valdez Martínez ,&nbsp;Mayra G. Mena-Enriquez ,&nbsp;Moises Ramos-Martinez ,&nbsp;R.E. Lozoya-Ponce","doi":"10.1016/j.jaecs.2025.100371","DOIUrl":"10.1016/j.jaecs.2025.100371","url":null,"abstract":"<div><div>70% of carbon emissions (CO₂) are generated from the excessive use of transport and industry. In the race for decarbonizing transport, biohydrogen holds a prominent position as a potential alternative to traditional fossil fuels with zero net emissions. New technologies or processes (Cryogenic separation, Membrane permeation, Electrochemistry, among others) are used to produce biohydrogen. One of the technologies that is gaining interest in research centers and industries is the Pressure Swing Adsorption (PSA) process. However, research is still needed to develop a PSA plant that mitigates disturbances, which directly affect the purity of biohydrogen (99%) that meets the criteria for use as biofuel. This article aims to propose a PSA plant for biohydrogen production using robust controllers (PID and geometric control) to mitigate disturbances and maintain a stable purity above 99%. By using geometric control, the adsorption capacity (molar fraction) increased to 0.55 CO₂, 0.04 CO, 0.04 CH₄ compared to the results obtained without control (0.35 CO₂, 0.021 CO, 0.01 CH₄), achieving a recovery greater than 60% with an energy efficiency of 0.64%. A biohydrogen productivity of 1.55<span><math><mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math></span> <span><math><mrow><mo>(</mo><mi>k</mi><mi>m</mi><mi>o</mi><mi>l</mi><mspace></mspace><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></mrow></math></span> was obtained with a final purity of 0.994 in the molar fraction. On the other hand, PID control presents a low adsorption capacity compared to those obtained with geometric control; likewise, a lower recovery of 55% was obtained, and an energy efficiency of 0.71% was used to obtain a purity of biohydrogen of 0.99 in molar fraction. It is concluded that the geometric control law offers greater robustness and performance in the face of disturbances that occur in a complex process such as PSA. Furthermore, this novel geometric control law produced improved results with a faster response to disturbance rejection, achieving greater productivity and purity, and meeting international standards for use as a biofuel.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100371"},"PeriodicalIF":5.0,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144926410","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}

{"title":"Experimental investigation on the thermoacoustic instability of boron/ethanol nanofluid fuel spray swirling flames","authors":"Meng Wang ,&nbsp;Zunyi Luo ,&nbsp;Chen Fu ,&nbsp;Kunpeng Liu ,&nbsp;Yongjun Wang ,&nbsp;Xiaoyang Wang ,&nbsp;Juan Yu ,&nbsp;Sheng Meng ,&nbsp;Man Zhang ,&nbsp;Yi Gao","doi":"10.1016/j.jaecs.2025.100376","DOIUrl":"10.1016/j.jaecs.2025.100376","url":null,"abstract":"<div><div>Nanofluid fuel has attracted the interest of researchers for decades due to its prominent combustion and propulsive properties. However, combustion instability is inevitable in propulsive systems, and little is known about how nanofluid fuel drive or dampen thermoacoustic oscillations of the system. A confined boron/ethanol (B/EtOH) nanofluid fuel spray swirling flame stabilized by an axisymmetric bluff body has been experimentally investigated in this work. The flame response to the varying B nanoparticles (NPs) doping concentrations was recorded and compared. 2D images and critical data were acquired using a 10 kHz repetition-rate OH* and BO₂* chemiluminescence (CL) system, a photomultiplier tube, and a pressure transducer. Meanwhile, several analysis methods, including flame visualization, Fourier/Hilbert transforms, spectrograms, proper orthogonal decomposition (POD), extended POD (EPOD), and Rayleigh's criterion analysis, are utilized to help us understand the underlying mechanism. From the averaged images, the high-intensity region of the BO₂*-CL appears further downstream than that of OH*-CL, resulting in a broader heat-release distribution of B/EtOH nanofluid fuel spray flames than neat EtOH ones. As the B NPs doping concentration increases, the oscillation frequency of the B/EtOH spray swirling flames remains almost unchanged, but the oscillation amplitude gradually decreases. Numerous B particles and agglomerates exhibit intense combustion when the micro-explosion phenomenon occurs. Additionally, the time-resolved pressure and heat release oscillations are out of phase and are supposed to be associated with acoustic energy dissipation. The POD and EPOD analyses reveal that the primary flame oscillations are driven by the longitudinal flame-shedding motion and the entrained reaction pockets. Meanwhile, the OH* and BO₂* radicals exhibit different local dynamics responses to the oscillation. Based on the Rayleigh index distribution coupling the fluctuation of pressure and heat release from EtOH and B, our study provides evidence that the combustion of B NPs downstream suppresses the thermoacoustic instability of the EtOH flames.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100376"},"PeriodicalIF":5.0,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932405","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}

{"title":"Coupled thermal runaway and combustion modeling for NMC811 Li-ion batteries safety: development and validation","authors":"Antonio García,&nbsp;Carlos Micó,&nbsp;Javier Marco-Gimeno,&nbsp;Imad Elkourchi","doi":"10.1016/j.jaecs.2025.100375","DOIUrl":"10.1016/j.jaecs.2025.100375","url":null,"abstract":"<div><div>Industrial lithium-ion battery deployment poses significant process safety risks due to thermal runaway events causing catastrophic fires and toxic gas releases. Accurate combustion modeling is essential for quantitative risk assessment and safety system design. This work presents a validated framework for process safety engineering applications. Accelerating rate calorimetry experiments were conducted on cylindrical cells of 18,650 format and NMC811 chemistry under inert and reactive atmospheres, capturing temperature profiles, pressure evolution, and gas compositions. Significant differences in vented gas mixtures were observed, with CO2, CO, and H₂ as dominant species. These results evaluated five combustion mechanisms: one for battery gas combustion, GRI-Mech 3.0, ANSYS Model Fuel Library and two-step global models. Homogeneous reactors and laminar flame speed simulations were used for evaluation. Detailed mechanisms produced consistent ignition delay and flame propagation results, while simplified models showed deviations. A mechanism reduction is presented, downscaling to 128 species and 794 reactions (80 % reduction) without compromising accuracy. This reduced mechanism was integrated into a 2D axisymmetric CFD model incorporating TR, gas venting, and combustion processes. The model accurately reproduced temperature rise, pressure development, and venting dynamics. The work provides a validated reduced kinetic mechanism for battery gas combustion that can be used to enhance safety of battery module during design processes.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100375"},"PeriodicalIF":5.0,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933526","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}

{"title":"Impact of MXene (Ti3C2) addition on ignition and combustion properties of boron particles","authors":"Andy Huynh ,&nbsp;Yue Jiang ,&nbsp;Mathias Kiefer ,&nbsp;Eunyoung Kim ,&nbsp;Dongwon Ka ,&nbsp;Andrew Demko ,&nbsp;Xiaolin Zheng","doi":"10.1016/j.jaecs.2025.100374","DOIUrl":"10.1016/j.jaecs.2025.100374","url":null,"abstract":"<div><div>Boron (B) offers high gravimetric and volumetric energy densities, making it an attractive solid fuel for energetic applications. However, boron is hard to ignite and burns slowly and incompletely due to the presence of surface B₂O₃, which has a low melting point but a high boiling temperature. Recently, a new class of two-dimensional materials known as MXene (Ti₃C₂) has emerged, exhibiting characteristics that could potentially enhance boron combustion, but this potential has not been previously explored. Herein, we experimentally investigate the ignition and combustion performance of boron particles, Ti₃C₂ nanosheets, and an 80 wt. % B/Ti₃C₂ mixture. We find that the addition of Ti₃C₂ nanosheets enhances both the ignition and combustion properties of boron particles. Specifically, Schlieren images of CO₂ laser ignition experiments show that the B/Ti₃C₂ mixture has a similar ignition delay time as Ti₃C₂ but is shorter than boron, and the mixture produces more gaseous products, indicating more oxidation. Bomb calorimetry measurements show that the B/Ti₃C₂ mixture’s heat of combustion is greater than the linear sum of its components, suggesting a favorable interaction between Ti₃C₂ and boron. Similarly, differential scanning calorimetry shows that the mixture releases more heat overall and has lower onset temperatures than pure boron oxidation. Variable-temperature X-ray diffraction analysis of B/Ti₃C₂ mixture shows the formation of anatase and rutile TiO₂, TiF₂, B₂O₃, and various mixed metal oxides at elevated temperatures due to reactions between boron and MXene or its oxidation products. In conclusion, these results demonstrate that Ti₃C₂ nanosheets, and potentially other MXenes, are effective additives for promoting boron combustion, leading to easier ignition and increased combustion efficiency.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100374"},"PeriodicalIF":5.0,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144913772","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}

{"title":"Modelling and simulation approaches for turbulent spray atomisation and combustion","authors":"Matthew J. Cleary ,&nbsp;Bosen Wang ,&nbsp;Zixin Chi ,&nbsp;Peihan Li","doi":"10.1016/j.jaecs.2025.100364","DOIUrl":"10.1016/j.jaecs.2025.100364","url":null,"abstract":"<div><div>The atomisation and combustion of liquid fuel sprays involve a complex interplay of processes, including interface dynamics, primary and secondary atomisation, droplet dispersion, evaporation, mixing, chemical reactions and heat release. These processes are influenced by multiscale turbulent interactions and interphase coupling. Accurate modelling of such flows requires integrating models for each process in a consistent, computationally efficient manner. This paper reviews the field, detailing key aspects and evaluating the performance of established and emerging modelling approaches within single-fluid and two-fluid paradigms. Emphasis is placed on large eddy simulation, conserved scalar formulations, and probability density function models, which offer elegant and tractable solutions for predicting spray atomisation and combustion.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100364"},"PeriodicalIF":5.0,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903207","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}

{"title":"Large eddy simulation study of ammonia dilute spray flames under MILD conditions","authors":"Zhenhua An,&nbsp;Yanhui Song,&nbsp;Jiangkuan Xing,&nbsp;Ryoichi Kurose","doi":"10.1016/j.jaecs.2025.100367","DOIUrl":"10.1016/j.jaecs.2025.100367","url":null,"abstract":"<div><div>Liquid ammonia has received increasing attention as a carbon-free fuel due to its potential to reduce the cost and size of power generation equipment. However, its practical application faces significant challenges, primarily related to its low combustion intensity and high NOx emissions. Moderate and intense low-oxygen dilution (MILD) combustion offers a promising approach to enhancing combustion stability while maintaining NOx emissions within acceptable limits. In this study, the flow and spray characteristics, combustion features, and emission performance of ammonia dilute spray flames are numerically investigated using a jet in hot co-flow (JHC) configuration. A range of co-flame temperatures and oxygen contents are considered. The gaseous ammonia jet flame is also studied as a comparison. The results indicate that under the JHC configuration, compared to gaseous ammonia combustion, liquid ammonia combustion reduces the heat release rate (HRR), increases the uniformity of the reaction zone, and reduces NOx emissions. Increasing the co-flame temperature and oxygen content reduces the spray penetration length and has minimal influence on the droplet size distribution. In addition, these changes lead to a transition in the combustion mode from premixed to diffusion. As the temperature and oxygen content increase, the maximum combustion temperature and HRR increase, the flame height decreases, and the lift-off distance is also affected. Moreover, a higher co-flame temperature leads to increased NO emissions but reduced N<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O emission, indicating the importance of optimizing the co-flame temperature for effective emission control. Increasing the oxygen content in the co-flame exacerbates NOx emissions, suggesting that a lower oxygen content should be maintained to minimize emissions. The findings of this study provide theoretical insights into the application of liquid ammonia under MILD combustion conditions.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"23 ","pages":"Article 100367"},"PeriodicalIF":5.0,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144888847","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}

{"title":"Numerical analysis of the unsteady transition of multiple laminar methanol/air spray flame structures in the counterflow configuration","authors":"Jiawei Wan,&nbsp;Eva Gutheil","doi":"10.1016/j.jaecs.2025.100363","DOIUrl":"10.1016/j.jaecs.2025.100363","url":null,"abstract":"<div><div>The counterflow configuration is a well-established setting to study the structure of laminar spray flames. Typically, the similarity transformation is introduced to transfer the two-dimensional gas-phase equations into one-dimensional governing equations. The equations which describe droplet motion are two-dimensional. For spray flames in the counterflow configuration, Continillo and Sirignano suggested that more than one numerical solution of these equations may exist, which meanwhile was confirmed by several studies. Up to three different structures were found for the same boundary conditions for the combustion of fuel sprays carried by air directed against an air stream. The first structure shows two chemical reaction zones one of which resides on the fuel side and the other one on the air side of the configuration. The other two spray flame structures show single chemical reaction zones that reside on one but different side of the stagnation plane. The present paper investigates the unsteady transition mechanisms between multiple methanol/air spray flame structures in the counterflow configuration. Perturbations are introduced to key parameters including gas strain rate, initial droplet size, and the equivalence ratio, to systematically analyze the physicochemical mechanisms that underlie the transitions between the different flame structures. The transitions, in general, result from the complex interplay between the spray vaporization and motion, which includes droplet reversal and oscillation, and the chemical reactions. The timescales of the transitions between the three different spray flame structures are analyzed in detail in the present paper.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"23 ","pages":"Article 100363"},"PeriodicalIF":5.0,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864312","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}

{"title":"Effects of wall heat loss on emission characteristics of liquid ammonia spray combustion using a swirling burner","authors":"Yi-Rong Chen ,&nbsp;Gauthier Reibel ,&nbsp;Kohei Oku ,&nbsp;Hirofumi Yamashita ,&nbsp;Akihiro Hayakawa ,&nbsp;Taku Kudo ,&nbsp;Hisayoshi Ito ,&nbsp;K. D. Kunkuma A. Somarathne ,&nbsp;Hideaki Kobayashi","doi":"10.1016/j.jaecs.2025.100370","DOIUrl":"10.1016/j.jaecs.2025.100370","url":null,"abstract":"<div><div>Liquid ammonia (LNH₃) spray combustion is considered to achieve zero carbon emissions without the need for a pre-vaporization system, thereby reducing costs. It enables rapid power adjustment to cope with the intermittency of renewable energy sources. However, LNH₃ evaporation absorbs energy, lowering the reaction temperature during fuel/air mixing. Low-temperature NH₃ reaction has been shown to produce deleterious substances, such as N₂O. Therefore, this study investigates the effects of wall heat loss (low-temperature region) on emissions during LNH₃ spray combustion in a swirling burner and compares the results to those from gaseous ammonia combustion. A liner with a cooling air jacket was designed to control the low temperature region by adjusting the air flowrate passing through the cooling cavity. As wall-cooling rose from 0 to 0.8 kW (approximately 0 % to 10 % of the total enthalpy input), overall emissions analyses showed increased unburned NH₃ and N₂O, alongside a reduction in NO emissions on the fuel-lean side, likely due to flame quenching near the wall and decreased flame temperature. To mitigate the production of harmful emissions under increased heat loss, two-stage combustion was applied. This approach significantly reduced unburned NH₃; however, N₂O and NO emissions remained comparable to those from single-stage combustion. Moreover, we compared the emissions at the wall and center under fuel-lean conditions, revealing higher NO emissions and near-zero unburned NH₃ and N₂O emissions at the center under increased cooling air flow, highlighting the influence of wall cooling on overall emissions characteristics.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"23 ","pages":"Article 100370"},"PeriodicalIF":5.0,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860363","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}

{"title":"CFD simulations on hydrodynamics and performance of air reactor during chemical looping combustion","authors":"Xiaobiao Ma,&nbsp;Boxian Zhao,&nbsp;Xue Lv,&nbsp;Jing Liu,&nbsp;Yingju Yang","doi":"10.1016/j.jaecs.2025.100365","DOIUrl":"10.1016/j.jaecs.2025.100365","url":null,"abstract":"<div><div>The optimal design of the reactors is of great significance for the efficient operation and scaling-up of the chemical looping combustion system. Here, the hydrodynamics and performance of the air reactor on a 10 kW_th series fluidized bed during chemical looping combustion were investigated via three-dimensional Eulerian-Eulerian multiphase simulations. The comprehensive influence of fluidization velocity, solid circulation rate, and bed height on axial pressure distribution, oxygen carrier conversion, and O₂ consumption was systematically evaluated through orthogonal experimental design. The simulation and variance analysis indicate that the fluidization velocity has a significant influence on O₂ consumption and Fe₂O₃ regeneration (p &lt; 0.05). The lower fluidization velocity can prolong the gas-solid contact time and improve the oxygen utilization efficiency, which is conducive to Fe₂O₃ regeneration. The bed height exhibits a nonlinear relationship with the energy consumption of the system, and the energy consumption reaches its peak at 150 mm. The energy utilization efficiency can be greatly improved by lowering the bed height. The higher solid circulation rate will shorten the residence time of Fe₃O₄ particles, resulting in an increase in the escape of unoxidized Fe₃O₄ particles. When the solid circulation rate increases from 1 m/s to 3 m/s, the escape rate of Fe₃O₄ rises to 65 %. Under the conditions of the fluidization rate of 1 m/s, the bed height of 100 mm, and the solid circulation rate of 1 m/s, the conversion rate of Fe₃O₄ can reach 98 %, and the outlet O₂ concentration is the lowest. Hence, the optimal performance of the air reactor can be achieved by adopting lower fluidization velocity and solid circulation rate. This work provides important theoretical guidance for the design and operation optimization of air reactors during chemical looping combustion.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"23 ","pages":"Article 100365"},"PeriodicalIF":5.0,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864321","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}

{"title":"Effects of thermodynamic pressure on laminar spray flame propagation into monodisperse fuel droplet-mists","authors":"Gulcan Ozel-Erol ,&nbsp;Merve Kucuk ,&nbsp;Nilanjan Chakraborty","doi":"10.1016/j.jaecs.2025.100366","DOIUrl":"10.1016/j.jaecs.2025.100366","url":null,"abstract":"<div><div>The effects of droplet diameter, overall equivalence ratio (0.8–1.5), and primary evaporation zone length (2–10 mm) on the burning velocity and thermal flame thickness in laminar n-heptane monodisperse spray flames under varying pressures (1.0–2.0 bar) have been analysed using 1D numerical simulations. It is observed that for gaseous premixed flames, both flame speed and thickness decrease with increasing pressure. However, in spray flames, flame thickness increases while burning velocity decreases as pressure rises, primarily due to reduced evaporation rates that limit fuel vapor availability. Larger droplet sizes further diminish evaporation rates, which lowers burning velocity and increases flame thickness, regardless of pressure. The finite evaporation rate also results in local equivalence ratios that are lower than the overall equivalence ratio in the heat release zone within the flame, especially at high pressures and with large droplets. In overall fuel-rich mixtures (e.g., for an overall equivalence ratio of 1.5), this can lead to more reactive gaseous mixtures and higher burning velocities than corresponding gaseous premixed flames, particularly for small droplets. Notably, the burning velocity in some spray flames can exceed the burning velocity of the corresponding premixed flames at the same gaseous-phase equivalence ratio at the heat release rate location. Enhanced burning velocity is also attributed to the generation of reactive species (e.g., H₂, C₂H₂, C₂H₄) from droplet evaporation and pyrolysis behind the flame front, which diffuse back into the reaction zone and accelerate the combustion process. However, the formation of these species diminishes at higher pressures, reducing this enhancement effect.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"23 ","pages":"Article 100366"},"PeriodicalIF":5.0,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864323","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}