Article
Environmental Sciences
Daigeng Wu, Zhongwei Meng, Zhongqiang Bao, Meng Deng, Juan Ou, Zhou Chen
Summary: The study examines the gas and particle emission characteristics of carbon black oxidation process in the presence of water under different temperatures, Printex-U masses, and catalysts. The results show that temperature and Printex-U mass increase the emissions of CO, CO2, and particle number. Oxidation efficiency increases with temperature but decreases with Printex-U mass. Catalysts promote oxidation and reduce CO emission. Water reduces CO emission and oxidation efficiency but significantly increases particle number and expands particle size range.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Green & Sustainable Science & Technology
Yajin Lyu, Chang Xing, Li Liu, Jiangbo Peng, Wenkai Shen, Xin Yu, Penghua Qiu
Summary: This study experimentally investigated the influences of dilution rate and equivalence ratio on the flame characteristics of hydrogen-air micro-mixing combustion. The results showed that increasing the dilution rate reduces the flame area, while decreasing it generates more small-scale wrinkle structures.
Article
Energy & Fuels
Xiaofei Wei, Yejian Qian, Shun Meng, Yang Hua, Liang Qiu, Yu Sun, Juye Wan, Xuelong Zhang
Summary: The combination of coupling port water injection (PWI) and exhaust gas recirculation (EGR) has significant effects on spray water evolution, combustion, and emissions for stoichiometric natural gas engines. It improves combustion characteristics and reduces NOx emissions.
Article
Energy & Fuels
Kangmin Ju, Joonsuk Kim, Jungsoo Park
Summary: This study demonstrates the feasibility of using a diesel engine as a power generator for electric vehicles, and shows that downsized diesel engines have the potential to improve power output performance.
Article
Thermodynamics
Yu Xia, Nozomu Hashimoto, Osamu Fujita
Summary: Ammonia is a promising energy carrier for a carbon-neutral society, and solid particle cloud-ammonia co-combustion is an efficient method for reducing CO2 emissions in the thermal power generation sector. However, the turbulent flame propagation mechanism of this co-combustion process is still unknown. In this study, experiments were conducted to investigate and validate the general turbulent flame propagation mechanism of solid particle cloud-ammonia co-combustion. The results showed that the flame propagation velocity is influenced by the equivalence ratio of ammonia-oxidizer. Based on these findings, new numerical simulation models can be developed for solid particle cloud-ammonia co-combustion in the future.
COMBUSTION AND FLAME
(2022)
Article
Chemistry, Multidisciplinary
Jing Chen, Yan Su, Fangxi Xie
Summary: The potential of a transient control method called model-based engine charge control (MCCT) to reduce nitrogen oxide (NOx) emissions of a light-duty diesel vehicle was investigated. The MCCT function was activated by calibrating factor maps adjusted for various parameters. The relationship between electronic control unit signals and NOx emissions was analyzed during both the worldwide harmonized light-duty test cycle (WLTC) and real driving emission (RDE) cycle. The results showed that MCCT could achieve different degrees of reduction in engine-out and tail-pipe NOx emissions during WLTC and RDE.
Article
Chemistry, Multidisciplinary
Jing Chen, Yan Su, Fangxi Xie
Summary: The potential of using MCCT to reduce NOx emissions in a light-duty diesel vehicle was investigated in this study, focusing on the WLTC and RDE driving cycles. The MCCT function was activated by calibrating factor maps, and the relationship between electronic control unit signals and NOx emissions was analyzed. Results showed that MCCT could achieve varying degrees of reduction in engine-out and tail-pipe NOx emissions in both the WLTC and RDE cycles.
Article
Thermodynamics
Xiongbo Duan, Zhengxin Xu, Xingyu Sun, Banglin Deng, Jingping Liu
Summary: This study investigated the effects of different ABE ratios and injection timings on the combustion and emissions behaviors of diesel engines fueled with ABE/diesel blended fuel. The results showed that the combustion process of diesel engines fueled with ABE/diesel fuel was strongly affected by injection timing and EGR.
Article
Energy & Fuels
Zengqiang Zhu, Zhiqiang Mu, Yanju Wei, Ruiheng Du, Shenghua Liu
Summary: The performance of a heavy-duty pure methanol engine was evaluated and compared to the original natural gas engine through experiments. The results showed that the pure methanol engine had higher brake thermal efficiency and better tolerance to exhaust gas recirculation. Lower NOx and CO emissions were observed in the pure methanol engine, but higher HC emissions were recorded.
Article
Thermodynamics
Yu Xia, Nozomu Hashimoto, Osamu Fujita
Summary: Ammonia is a highly promising energy carrier for achieving a carbon-neutral society. The co-combustion of solid particle clouds-ammonia is considered an efficient method of reducing carbon dioxide emissions. Understanding the turbulent flame stabilization and extinguishment processes during this co-combustion is essential for its application in combustors.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Energy & Fuels
Chengjun Gao, Junquan Meng, Zhenrong Liu, Yuwei Hu, Junhua Wang, Jianxin Xu, Hua Wang, Rong Chen
Summary: The flue gas emissions from co-combustion of anthracite powder and water hyacinth were studied. The effects of combustion temperature, mixing ratio, and oxygen concentration on SO2 and NOx emissions were analyzed. The experimental results showed that the oxygen concentration had the greatest influence on SO2 and NOx emissions, followed by the mixing ratio and temperature.
CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION
(2023)
Article
Chemistry, Multidisciplinary
Diming Lou, Lulu Kang, Yunhua Zhang, Liang Fang, Chagen Luo
Summary: This paper studied the effect of EGR combined with SCR on the NOx emission characteristics of a heavy-duty diesel engine through engine bench testing. The results showed that the combination of EGR and SCR has a significant impact on NOx reduction rate, but has little effect on NO2 emission reduction. The study also found that the opening of the EGR valve and the ammonia NOx molar ratio have an influence on the NOx reduction rate, with different effects at different engine speeds.
Article
Chemistry, Physical
M. G. Gautham, Balkrishna C. Rao, P. A. Ramakrishna
Summary: The aluminum-water combustion method can be used to synthesize alumina and produce hydrogen gas, with exhaust gases containing a high proportion of hydrogen, which can be used for power generation. By controlling the oxidizer to fuel ratio, high purity alumina can be obtained from the residue of the combustion process.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Thermodynamics
Suja Thangaraj, Nagarajan Govindan
Summary: This study investigates the combustion, performance and emission characteristics of water electrolyzed hydroxyl gas and compressed natural gas in a diesel engine. The results show that the multi fuel mode reduces NOx emission and smoke density compared to pure diesel operation, and improves fuel economy and power through better combustion.
Article
Thermodynamics
Yu Xia, Khalid Hadi, Genya Hashimoto, Nozomu Hashimoto, Osamu Fujita
Summary: This paper reports the fundamental mechanism of flame propagation for pulverized coal/ammonia co-combustion, with experiments clarifying the effects of equivalence ratio of ammonia-oxidizer mixture on flame propagation velocity. Results suggest that the flame propagation velocity of pulverized coal/ammonia was higher than that of pure coal combustion, with variations depending on the equivalence ratio. The unique mechanism includes three competing effects, explaining the relationship between flame propagation velocity and equivalence ratio in ammonia lean and rich conditions.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Sophie Colson, Yuta Hirano, Akihiro Hayakawa, Taku Kudo, Hideaki Kobayashi, Cedric Galizzi, Dany Escudie
Summary: The study investigated the application of ammonia/methane mixtures in flames and the prediction of extinction stretch rate by different numerical mechanisms. Experimental results showed that all mechanisms struggled to accurately predict the extinction rate in premixed flames, while Okafor’s mechanism performed better in non-premixed flames.
COMBUSTION SCIENCE AND TECHNOLOGY
(2021)
Article
Energy & Fuels
Yu Xia, Genya Hashimoto, Khalid Hadi, Nozomu Hashimoto, Akihiro Hayakawa, Hideaki Kobayashi, Osamu Fujita
Article
Thermodynamics
Sophie Colson, Manuel Kuhni, Cedric Galizzi, Dany Escudie, Hideaki Kobayashi
Summary: This study investigates the effects of ammonia addition on conventional fuels flame stabilization. It is found that ammonia addition leads to a sharp reduction in the stabilization domain and the flame cannot be stabilized. Additionally, an increase in the coflow velocity results in a decrease in the re-attachment velocity of the flame.
COMBUSTION SCIENCE AND TECHNOLOGY
(2022)
Article
Energy & Fuels
Ekenechukwu C. Okafor, Hirofumi Yamashita, Akihiro Hayakawa, K. D. Kunkuma A. Somarathne, Taku Kudo, Taku Tsujimura, Masahiro Uchida, Shintaro Ito, Hideaki Kobayashi
Summary: This study successfully conducted liquid ammonia spray combustion under preheated air conditions, demonstrating that preheated air can enhance the dispersion and evaporation of the liquid droplets, thereby reducing spray height and achieving stable combustion of liquid ammonia spray alone.
Article
Thermodynamics
Akihiro Hayakawa, Yuta Hirano, Ekenechukwu C. Okafor, Hirofumi Yamashita, Taku Kudo, Hideaki Kobayashi
Summary: The product gas characteristics of ammonia/air premixed laminar flames were investigated experimentally and numerically under various equivalence ratios up to elevated pressure conditions. Experimental results showed that the maximum NO mole fraction was about 3,500 ppmv at an equivalence ratio of 0.9 and decreased with increasing equivalence ratio. The study also found that updating reaction models may be necessary for accurate prediction of product gas characteristics of ammonia/air flames.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Ekenechukwu C. Okafor, Masaaki Tsukamoto, Akihiro Hayakawa, K. D. Kunkuma A. Somarathne, Taku Kudo, Taku Tsujimura, Hideaki Kobayashi
Summary: The study investigates the influence of wall heat loss on ammonia-air swirling flames, finding that heat loss strongly affects the flames, leading to flame quenching and increased emissions of unburned NH3, while also promoting the extension of fuel-rich stabilization limit.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Kapuruge Don Kunkuma Amila Somarathne, Ekenechukwu C. Okafor, Daiki Sugawara, Akihiro Hayakawa, Hideaki Kobayashi
Summary: This study investigated the effects of OH concentration and temperature on NO emissions in turbulent, non-premixed methane/ammonia/air swirl flames at high pressure. Utilizing far-rich equivalence ratios could significantly reduce NO emissions from CH4/NH3 flames. Local flame characteristics were found to be qualitatively similar to NH3/air flames, but temperatures and OH concentrations decreased gradually with NH3 substitution.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Genya Hashimoto, Khalid Hadi, Yu Xia, Aainaa Hamid, Nozomu Hashimoto, Akihiro Hayakawa, Hideaki Kobayashi, Osamu Fujita
Summary: Ammonia is a promising energy carrier that can be used as a carbon-neutral fuel, but its low-burning velocity makes it challenging to use in conventional combustors. Mixing ammonia with methane can enhance its combustibility, allowing for an extended flame propagation limit.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Sophie Colson, Manuel Kuhni, Akihiro Hayakawa, Hideaki Kobayashi, Cedric Galizzi, Dany Escudie
Summary: Ammonia is a promising alternative fuel for CO 2 emission reduction, especially in existing facilities running on natural gas. This study focuses on ammonia/methane blend fuels and investigates the effect of ammonia on methane jet flame stabilization. The research highlights the impact of ammonia addition on flame position, heat transfer, and the transition between different stabilization regimes.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Gabriel J. Gotama, Akihiro Hayakawa, Ekenechukwu C. Okafor, Ryuhei Kanoshima, Masao Hayashi, Taku Kudo, Hideaki Kobayashi
Summary: The study focuses on the chemical kinetics of NH3/H-2/air flames at rich conditions and elevated pressures, validating a new detailed kinetics mechanism that accurately predicts flame speed.
COMBUSTION AND FLAME
(2022)
Article
Energy & Fuels
Ryuhei Kanoshima, Akihiro Hayakawa, Takahiro Kudo, Ekenechukwu C. Okafor, Sophie Colson, Akinori Ichikawa, Taku Kudo, Hideaki Kobayashi
Summary: The study focused on investigating the laminar burning velocities and Markstein lengths of ammonia/air mixtures under high-temperature and high-pressure conditions, and compared the effects with methane/air mixtures. Results showed that temperature exponent of ammonia flames was larger and had greater impact on reaction rate compared to methane flames, while pressure exponent of ammonia flames was closer to zero.
Article
Energy & Fuels
Masao Hayashi, Akihiro Hayakawa, Taku Kudo, Hideaki Kobayashi
Summary: Since the Industrial Revolution, large amounts of ammonia synthesized by the Haber-Bosch process have been used as fertilizer and chemical materials. However, the nitrogen cycle has been found to exceed the limits of the planetary boundary and pose a serious environmental pollution issue. Therefore, a nitrogen cycle that collects nitrogen compounds from the environment and releases them into the atmosphere has been proposed. This study aims to clarify the effects of water vapor dilution on the laminar flame characteristics of ammonia flames.
Article
Thermodynamics
Yasuhiro Higuchi, Yoshio Nunome, Satoshi Takada, Ryoma Yoshikawa, Taku Kudo, Akihiro Hayakawa, Hideaki Kobayashi
Summary: This paper focuses on the application of quantitative OH laser-induced fluorescence (OH-LIF) method for high-pressure and high-temperature flames. The OH(2,0) band LIF combined with bidirectional LIF methods is proposed for quantitative measurement of OH concentration. The results show that the OH(2,0) band bidirectional LIF method is feasible for measuring OH concentration in high-pressure and high-temperature flames.
JOURNAL OF THERMAL SCIENCE AND TECHNOLOGY
(2022)
Article
Thermodynamics
Satoshi Kadowaki, Thwe Thwe Aung, Taisei Furuyama, Kazumasa Kawata, Toshiyuki Katsumi, Hideaki Kobayashi
Summary: The effects of pressure and heat loss on the unstable motion of cellular-flame fronts in hydrogen-air lean premixed flames were numerically investigated. It was found that an increase in pressure resulted in higher growth rate and wider unstable range, while an increase in heat loss led to a decrease in growth rate and unstable range. Additionally, the pressure and heat loss were observed to strongly impact the burning velocity and fractal dimension of the flame fronts, making the flame shape more complex.
JOURNAL OF THERMAL SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Aerospace
Tatsuya Yamaguchi, Tomohiro Hizawa, Yasuto Yugami, Mariko Hasegawa, Taku Kudo, Akihiro Hayakawa, Hideaki Kobayashi
TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES
(2020)