Journal of The Energy Institute最新文献

{"title":"Experimental study of ammonia energy ratio on combustion and emissions from ammonia-gasoline dual-fuel engine at various load conditions","authors":"Yan Wu ,&nbsp;Jie Hu ,&nbsp;Yi Lin ,&nbsp;Peng Chen ,&nbsp;Gang Chen ,&nbsp;Zhihong Wang","doi":"10.1016/j.joei.2024.101868","DOIUrl":"10.1016/j.joei.2024.101868","url":null,"abstract":"<div><div>Achieving carbon neutrality necessitates the adoption of zero-carbon fuels in engine applications, with ammonia emerging as an up-and-coming candidate due to its favorable safety profile and advantages in storage and transportation. This study experimentally investigated the feasibility of an ammonia-gasoline dual-fuel (AGDF) engine to achieve comparable power output and satisfactory carbon reduction without changing the main structural parameters of the engine. A four-cylinder, naturally aspirated, spark ignition engine was used to investigate the impact of ammonia energy ratio (AER), engine base torque and engine speed on the engine performance, combustion evolution and emission characteristics. The findings reveal that the brake thermal efficiency (BTE) in AGDF mode is lower than in gasoline-only mode, primarily due to the reduced combustion activity. However, this efficiency decline becomes noticeable only when the AER exceeds 15 %. Additionally, at high AERs and high engine base torques, the delayed effect of ammonia fuel on the main combustion period results in a double-peak pattern, which limits the energy output but presents opportunities for phase optimization. The study also examined three incomplete combustion emissions, each exhibiting distinct behaviors. Except for ammonia slip, adding ammonia fuel does not significantly affect carbon monoxide (CO) and unburned hydrocarbons (UHC) emissions, particularly at AERs below 25 %. Nevertheless, nitrogen oxide (NOx) emissions under AGDF combustion are significantly higher than under gasoline alone in most instances. Crucially, the study demonstrates the carbon reduction potential of ammonia fuel across different engine loads, with a maximum carbon dioxide (CO₂) reduction of 46.8 % at a 35 % AER. It is anticipated that further optimization of the combustion phase will improve the capability for carbon reduction.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101868"},"PeriodicalIF":5.6,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermodynamic and molecular dynamics study of methane dry reforming","authors":"Qingsong Zou ,&nbsp;Kejiang Li ,&nbsp;Xiangyu He ,&nbsp;Alberto N. Conejo ,&nbsp;Jianliang Zhang ,&nbsp;Chunhe Jiang ,&nbsp;Zeng Liang ,&nbsp;Zonghao Yang","doi":"10.1016/j.joei.2024.101870","DOIUrl":"10.1016/j.joei.2024.101870","url":null,"abstract":"<div><div>The carbon neutrality strategy presents both challenges and opportunities for the metallurgical industry. Hydrogen, recognized as a green energy source, demonstrates significant potential for application in metallurgy. The negative impact of carbon deposition on catalysts is a significant challenge in the large-scale industrial application of methane dry reforming to produce hydrogen-rich reducing gases for ironmaking. This paper investigates the reaction mechanism through thermodynamic calculations and molecular dynamics simulations, systematically examining the effects of temperature, pressure, and feed ratio on the composition of gas products and the amount of carbon precipitation during the preparation process of hydrogen-rich reduction gas. The optimal conditions to produce high-quality reducing gas are identified to be a CO₂/CH₄ ratio of 0.8 at 1100K and 1 atm. At elevated temperatures, increasing the amount of carbon dioxide can reduce the amount of precipitated carbon, while the opposite is true at lower temperatures. The carbon absorbed by the nickel-based catalyst primarily originates from methane, while hydrogen ions activate carbon dioxide to produce carbon monoxide or carboxyl groups. By elucidating the reaction mechanism and quantifying the carbon precipitation, we provide theoretical guidance for industrial application.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101870"},"PeriodicalIF":5.6,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of thermophysical properties on heterogeneous reaction dynamics of methane/oxygen mixtures in a micro catalytic combustion chamber","authors":"Muhammad Nauman ,&nbsp;Jianfeng Pan ,&nbsp;Qingbo Lu ,&nbsp;Yi Zhang ,&nbsp;Evans K. Quaye ,&nbsp;Feiyang Li ,&nbsp;Wenming Yang","doi":"10.1016/j.joei.2024.101871","DOIUrl":"10.1016/j.joei.2024.101871","url":null,"abstract":"<div><div>This paper presents a numerical investigation of premixed methane/oxygen heterogeneous reaction characteristics in a micro-catalytic combustion chamber under various boundary and wall thermophysical conditions. A 3-D model was simulated using ANSYS Fluent and validated against experimental data, with a maximum difference of only 1.92 % using a pure heterogeneous reaction. This study aims to analyze the wall boundary conditions and thermophysical factors that influence chemically and thermally during heterogeneous reactions. The results show that, with an increase in inlet velocity from 1 m/s to 10 m/s, the maximum heat produced by the reaction increases 52.67 % and the temperature of the channel as well as the outer wall increases accordingly. Using a 2.5 m/s inlet velocity, we found that the maximum external wall temperature uniformity coefficient was 0.1911. Furthermore, it was observed that as the heterogeneous reaction progresses, Platinum's surface coverage and the H_(s) site coverage increase; however, the O_(s), OH_(s), CO_(s), and C_(s) site coverage decreases. Additionally, low convective heat transfer and wall thermal conductivity increase the efficiency of heterogeneous reactions and methane conversion. As a result of the low wall thermal conductivity, the outer wall temperature uniformity coefficient was 0.2863, while the methane conversion rate was 79.05 %. According to the results, higher thermal resistance increased the methane conversion rate from 68.18 % to 79.05 %, and the combustion process within the micro-catalytic combustor was uniform and controlled, thus enhancing its efficiency. The results of this study provide useful insights for optimizing micro-combustors, paving the way for future improvements in their design and operational efficiency.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101871"},"PeriodicalIF":5.6,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on the impact of nitromethane on the combustion mechanism of ammonia/methanol blends","authors":"Yuan Zhuang ,&nbsp;Yihan Li ,&nbsp;Rui Zhai ,&nbsp;Yuhan Huang ,&nbsp;Xinyan Wang ,&nbsp;Lei Tang ,&nbsp;Ke Wang ,&nbsp;Shancai Tang ,&nbsp;Zhihong Lin","doi":"10.1016/j.joei.2024.101867","DOIUrl":"10.1016/j.joei.2024.101867","url":null,"abstract":"<div><div>Ammonia/methanol co-combustion is considered an effective liquid-liquid blending strategy to enhance the combustion performance of ammonia. However, both methanol and ammonia have high latent heats of vaporization, which necessitate significant heat absorption during the vaporization process. This often results in excessively low ambient temperatures before the ignition of the mixture, negatively affecting low-temperature ignition and combustion. To improve the combustion characteristics of ammonia/methanol blends, this study proposes the addition of nitromethane, forming a ternary blend of ammonia/methanol/nitromethane to enhance fuel performance. To evaluate the impact of nitromethane on the combustion mechanism of ammonia/methanol blends, this study utilizes synchronous vacuum ultraviolet photoionization mass spectrometry to analyze the oxidation reactions of the ammonia/methanol/nitromethane blends. Based on the Brequigny model, cross-reactions involving C-N bonds and reactions related to nitromethane were incorporated for model modification, resulting in the newly modified model, termed A-M. Pathway and sensitivity analyses, as well as ignition delay time simulations, were conducted to further understand the combustion process. The results indicate that the addition of nitromethane to the ammonia/methanol blend lowers the initial reaction temperature from 860 K to 740 K and increases nitrogen oxide (NO_x) concentrations at 1050 K. At 800 K, nitromethane reduces the conversion of NH₂ to NH₃, thereby enhancing ammonia consumption and altering the NO_x consumption pathway. Furthermore, at 1020 K, 98.6 % of H₂NO reacts with H to form NH₂, which is a crucial species in ammonia regeneration. Additionally, at 1020 K, 90.8 % of nitromethane decomposes through the reaction CH₃NO₂(+M) = CH₃ + NO₂(+M), contributing to increased NO_x emissions. Moreover, the incorporation of nitromethane significantly reduces the ignition delay time of ammonia/methanol blends, demonstrating its potential to improve the overall combustion performance of these mixtures.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101867"},"PeriodicalIF":5.6,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrothermal bio-oil yield and higher heating value of high moisture and lipid biomass: Machine learning modeling and feature response behavior analysis","authors":"Xiangjie Liu ,&nbsp;Xin Zhang ,&nbsp;Khantaphong Charoenkal ,&nbsp;Qiaoxia Yuan ,&nbsp;Hongliang Cao","doi":"10.1016/j.joei.2024.101859","DOIUrl":"10.1016/j.joei.2024.101859","url":null,"abstract":"<div><div>The yield and higher heating value (HHV) of bio-oil products are significant performance parameters for the hydrothermal conversion of high-water and high-lipid biomass. Machine learning (ML) modeling prediction is a fast and convenient means of obtaining performance parameters. An informative dataset with 243 samples was prepared, and two highly adapted ML algorithms were used: Random Forest (RF) and Extreme Gradient Boosting Tree (XGBoost). It is interesting to note that the developed ML models demonstrated great prediction ability; for example, the regression coefficient (<span><math><mrow><msup><mi>R</mi><mn>2</mn></msup></mrow></math></span>) of the XGBoost model for yield and HHV prediction was as high as 0.942 and 0.940, respectively. Furthermore, partial dependence plots (PDP) and SHapley Additive exPlanations (SHAP) interpretability methodologies were adopted to address the main contributions of the feature identification and response behavior analysis of the features. The results demonstrated that the biomass composition had the greatest effect on bio-oil yield, with fat contributing up to 40 %. In contrast, the elemental composition had the most significant effect on the HHV of bio-oil. Notably, hydrogen content affected the HHV of up to 4.5 units. The interaction response behavior showed that the interaction of the process parameters with feedstock properties was most common and significant. The information obtained from the response mechanism can be used to enhance the subsequent hydrothermal fuel preparation process for bio-oils.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101859"},"PeriodicalIF":5.6,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new low NOx emission technique for NH3/H2 blends in a flameless combustor through offset injection","authors":"Mohammad Kalamuddin Ansari ,&nbsp;Shawnam ,&nbsp;Anand Shankar Singh ,&nbsp;Bhupendra Khandelwal ,&nbsp;Sudarshan Kumar","doi":"10.1016/j.joei.2024.101864","DOIUrl":"10.1016/j.joei.2024.101864","url":null,"abstract":"<div><div>The application of ammonia (NH₃) as a possible future fuel presents a plausible solution for green energy storage. It helps provide a carbon-neutral fuel alternative for industrial power generation and transportation. However, the combustion of NH₃ presents a formidable challenge due to its low reactivity, inadequate flame stability, sluggish flame propagation, and high NO_x emissions. Consequently, its integration into combustion systems necessitates substantial system and strategy modification to enable its deployment to industrial systems. The current study presents a novel fuel/air injection technique, which emphasizes the high recirculation of hot combustion products and the extended residence time of fuel/air mixtures. A comprehensive experimental and numerical investigation is conducted using a swirl air injection and offset fuel injection to achieve the flameless combustion mode for optimized NH₃/H₂ fuel blends. A range of mixture conditions (ϕ = 0.5–1.2) and NH₃/H₂ compositions (50/50–70/30) are experimentally examined. The investigations helped elucidate the effect of residence time and recirculation on NO_x emissions through kinetic simulations using a reactor network model. Subsequently, 3-D numerical simulations helped identify regions of high recirculation, quantified through reactant dilution ratios and uniform temperature distribution. These aspects are determined using a new parameter, the temperature uniformity index along the axial direction of the combustor. The emissions of NO_x, unburnt NH₃, and unburnt H₂ are quantified for different equivalence ratios and NH₃ mole fractions in the fuel mixture. The investigations reveal that NO_x emissions reached their minimum (450–654 ppm) and (344-211 ppm), when the burner operated at lean (ϕ = 0.5–0.8) and rich (ϕ = 1.0–1.2) conditions, respectively, for 70/30 NH₃/H₂ blend. The emissions of unburnt NH₃ and H₂ species remain minimal for lean conditions. Both lean and rich operational regimes demonstrated similar or superior emission characteristics in flameless combustion mode when compared to the conventional combustion mode.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101864"},"PeriodicalIF":5.6,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and modeling studies on char combustion under pressurized O2/H2O conditions","authors":"Kun Chen,&nbsp;Chenxi Bai,&nbsp;Wenda Zhang,&nbsp;Yijun Zhao,&nbsp;Dongdong Feng,&nbsp;Shaozeng Sun","doi":"10.1016/j.joei.2024.101858","DOIUrl":"10.1016/j.joei.2024.101858","url":null,"abstract":"<div><div>The desorption kinetic parameters for pressurized combustion and gasification reactions were determined based on a C++ program coupled with the Langmuir-Hinshelwood (L-H) kinetic model developed and experimental data from pressurized char combustion, and the established L-H kinetic model for pressurized char-O₂/H₂O combustion was refined in the current paper. The activation energy for desorption in reactions involving pressurized char-O₂ and char-H₂O was determined to be 250.8 kJ/mol, accompanied by a pre-exponential factor of 5.42 × 10¹⁰ g/(m² s). Using this foundation, the current research conducted simulations to investigate the impacts of temperature, pressure, and H₂O concentration on the oxidation adsorption rate (<em>R</em>_ads,oxi), desorption rate (<em>R</em>_des), gasification adsorption rate (<em>R</em>_ads,gas), and the competitive influences of kinetics and diffusion processes within the pressurized char-O₂/H₂O combustion. The simulation results indicate a gradual increase in <em>R</em>_des and <em>R</em>_ads,gas with char conversion to reach a peak, followed by a gradual decline. Conversely, the <em>R</em>_ads,oxi varies smoothly throughout the char conversion process. At 1673 K/1.0 MPa, the char-O₂/H₂O reaction rate is primarily constrained by <em>R</em>_ads,oxi and <em>R</em>_ads,gas, with the adsorption reaction serving as the rate-controlling step. Moreover, it was noted that a rise in pressure resulted in a linear increase in <em>R</em>_ads,oxi, <em>R</em>_des, and <em>R</em>_ads,gas. At elevated temperatures, the impact of pressure on them becomes more noticeable. However, the introduction of H₂O mitigates this effect. Elevated temperature and pressure facilitate the competition on the kinetics of char-O₂ combustion for O₂ diffusion, resulting in the conversion of char being more susceptible to O₂ diffusion rate limitation. With the addition of 20 % H₂O, the competition effect was weakened. In the case of pressurized combustion involving char and O₂/H₂O, the char conversion is primarily constrained by the O₂ diffusion rate and is scarcely influenced by the H₂O diffusion rate.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101858"},"PeriodicalIF":5.6,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of NOx emission characteristics in air-staged combustion system fueled by premixed ammonia/methane","authors":"Weiguo Pan ,&nbsp;Ningning Yao ,&nbsp;Yifeng Chen ,&nbsp;Lianwei Kang","doi":"10.1016/j.joei.2024.101857","DOIUrl":"10.1016/j.joei.2024.101857","url":null,"abstract":"<div><div>For the purpose of achieving global CO₂ reduction, decarbonization at the source of fuels is a practical approach. The transition phase of blending fossil fuels with carbon-free fuels for combustion is a hot topic in the current carbon emission reduction process. In order to achieve efficient and low-pollution combustion of NH₃/CH₄, the combustion and emission characteristics of NH₃/CH₄ under single-stage and air-staged combustion methods were numerically investigated in this work. The emissions were compared for different equivalence ratios and different ammonia content conditions. Rate of production (ROP) and sensitivity analysis were performed for NO_x, and the reaction path of NH₃/CH₄ was analyzed. The results indicate that the C-N interaction of the NH₃/CH₄ mixed combustion process is not significant and turns weaker in the lean flames. HNO intermediate is an important specie for NO generation, and HCN together with HCO intermediate, are essential species for CO generation. NH₂ and NH almost dominate the promotion and inhibition of NO generation. Given the contrasting NO_x and CO emission behavior of NH₃/CH₄ in rich and lean flames, the single-stage combustion approach is not suitable. Air-staged combustion achieves both, ensuring the complete burning of NH₃ and CH₄ while reducing NO_x and CO emissions. Moreover, the results suggest that <em>Φ</em>_pri = 1.2/<em>Φ</em>_total = 0.6 is the optimal NH₃/CH₄ combustion staging method for controlling NO_x emissions.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101857"},"PeriodicalIF":5.6,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical study on influences of intake temperature and swirl ratio on in-cylinder combustion and pollutant formation characteristics of ammonia/diesel dual-fuel engine","authors":"Yuhang Lu ,&nbsp;Mingliang Wei ,&nbsp;Xidong Wang ,&nbsp;Qian Ji ,&nbsp;Chengcheng Ao ,&nbsp;Xintao Wang ,&nbsp;Junheng Liu","doi":"10.1016/j.joei.2024.101860","DOIUrl":"10.1016/j.joei.2024.101860","url":null,"abstract":"<div><div>In order to improve the combustion efficiency of ammonia fuel, and enhance the operational stability and emission level for ammonia engines, this study constructs an in-cylinder combustion numerical model of ammonia/diesel dual-fuel engine based on CONVERGE software, and investigates the effects of initial intake temperature and swirl intensity on in-cylinder combustion and pollutant formation characteristics of ammonia/diesel dual-fuel engine. The results show that increasing the intake temperature can improve the in-cylinder thermal atmosphere, advance the dual-fuel combustion reaction process, and increase the peak in-cylinder combustion pressure and temperature. The peak in-cylinder pressure increases from 6.05 to 6.44 MPa when the intake temperature is increased from 303 to 343 K. This is effective in improving the emissions of incomplete combustion for the ammonia/diesel dual-fuel engine. The in-cylinder unburned NH₃, CO and HC emissions are reduced by 20.2 %, 77.1 % and 88.21 %, respectively. Increasing the swirl ratio enhances the in-cylinder gas disturbance, reduces the amount of fuel attached to the wall, and improves the quality of in-cylinder fuel-gas mixture. It also accelerates the process of combustible mixture formation, advances the starting point of ammonia fuel consumption, and accelerates the initial reaction rate. When the swirl ratio is increased from 0.5 to 3.0, the in-cylinder unburned NH₃ emission is reduced by 14.85 %. Reasonable adjustment of intake temperature and swirl ratio helps to improve the distribution of direct injection fuel particles inside the cylinder, thereby optimizing the dual-fuel combustion process and enhancing engine performance.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101860"},"PeriodicalIF":5.6,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of ammonia reforming on combustion and emission characteristics of a 4-valve engine with an active pre-chamber","authors":"Lin Chen ,&nbsp;Fangjia Yan ,&nbsp;Ren Zhang ,&nbsp;Haiqiao Wei ,&nbsp;Jiaying Pan","doi":"10.1016/j.joei.2024.101861","DOIUrl":"10.1016/j.joei.2024.101861","url":null,"abstract":"<div><div>Ammonia (NH₃), as a hydrogen carrier and carbon-free fuel, offers an attractive opportunity for engines to achieve carbon neutrality. Turbulent jet ignition (TJI) combined with ammonia reforming shows the great capacity in ammonia-fueled engines. In this study, the effects of reforming strategy in an ammonia-fueled TJI are numerically studied, addressing the reforming ratio and reforming region. The results show that when only using reformate in the pre-chamber, the promoting effect of jet flame is more effective on the initial combustion phase. There are still very high NH₃ emissions due to the low reactivity in the main chamber. Further using reformate both in the pre-chamber and the main chamber, all the combustion stages (ST-CA10, CA10-50, CA50-90) can be shortened almost linearly with the increase of reforming ratio. Besides, the unburned NH₃ can be reduced to an acceptable level when the reforming ratio reaches 200 ‰ (hydrogen energy ratio of 18.50 %). The main reason is that the jet-induced strong flow field is coincident with the whole combustion stage. Further increasing the reforming ratio (pure hydrogen) in the pre-chamber, a high combustion efficiency and acceptable NH₃ emission can be achieved at a low hydrogen energy ratio (7.08 %). However, knocking combustion will happen at high reforming ratio with a low knock intensity. The results can provide some guidance for making the best-promoting benefit of the limited hydrogen in ammonia TJI engines with different reforming strategies.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":"117 ","pages":"Article 101861"},"PeriodicalIF":5.6,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}