Article
Chemistry, Physical
Qiang Cheng, Zeeshan Ahmad, Ossi Kaario, Ville Vuorinen, Martti Larmi
Summary: The experiments investigate the combustion characteristics of diesel pilot spray ignited methane-hydrogen (CH4-H-2) combustion, known as tri-fuel combustion (TF), in a single-cylinder compression ignition (CI) engine. The addition of hydrogen (H-2) up to 60% is found to decrease ignition delay time (IDT) and combustion duration, leading to an increase in indicated thermal efficiency (ITE) by up to 10%. The study also highlights that lower H-2 concentration and charge-air temperature can reduce pressure oscillations and cycle-to-cycle variations (CCV), while higher concentrations and temperatures may result in abnormal combustion and knocking.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Energy & Fuels
Alexis Cova-Bonillo, Rayda Patino-Camino, Juan Jose Hernandez, Magin Lapuerta
Summary: This study analyzes the impact of water concentration in ethanol on the autoignition characteristics of ethanol-diesel blends. The results indicate that water content has little effect on autoignition times in general, but acts as a reactivity inhibitor at low hydrated ethanol contents and as an autoignition enhancer at higher concentrations. The chemical effect associated with water as a third-body becomes more important at higher concentrations.
Article
Chemistry, Physical
Xufeng Yang, Minggao Yu, Shixin Han, Zhenmin Luo
Summary: This study experimentally investigates the premixed flame of stoichiometric syngas-air mixture with various hydrogen volume fractions propagating in a duct with both ends open. Results show that the ignition location affects the flame morphology and propagation speed. The flame propagation process in the duct with both ends open is moderated by various factors.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Thermodynamics
Seunghyun Jo, Jay P. Gore
Summary: New measurements of laser ignition energy in flowing turbulent hydrogen-air mixture jets are reported. The minimum reliable ignition energy (MRIE) increases with an increase in bulk velocity. A phenomenological model equating the MRIE to the energy losses calculated using the flame kernel volume, the kernel temperature, the mixture properties, and the flame speed is proposed.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Miguel Figueroa-Labastida, Minh B. Luong, Jihad Badra, Hong G. Im, Aamir Farooq
Summary: Experimental and computational investigations were conducted to identify the generalized criterion for predicting the preignition tendency of methanol and ethanol mixtures in shock tubes. The Sankaran number criterion was found to be the most successful predictor of the experimental observations.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Suozhu Pan, Kai Cai, Min Cai, Chenbo Du, Xin Li, Weiqiang Han, Xin Wang, Daming Liu, Jiangjun Wei, Jia Fang, Xiuchao Bao
Summary: The study focused on investigating the cyclic variations of ethanol/diesel RCCI combustion on a heavy-duty diesel engine by studying the effects of diesel injection timing and premixed ratio (PR). The results showed that the cyclic variations are sensitive to the diesel injection timing and PR, emphasizing the importance of optimizing these parameters for smoother operation.
Article
Thermodynamics
Binbin Wang, Hechun Wang, Deng Hu, Chuanlei Yang, Baoyin Duan, Yinyan Wang
Summary: To address the issue of in-cylinder knock caused by premixed natural gas combustion in engines, the blending of ammonia in natural gas can be utilized to slow down combustion rate and prevent knock combustion. This study investigates the impact of diesel ignition on engine combustion and emission performance of premixed natural gas/ammonia through simulation, considering 10 different ammonia blending ratios ranging from 0% to 90%. The findings indicate that with the increase of ammonia blending ratio, engine dynamics gradually decrease, while the lowest fuel consumption rate can be achieved at a 60% ammonia blending ratio. The increase in ammonia blending ratio and slit effect leads to an increase in unburned ammonia in the piston ring gap, resulting in significant reduction in CO2 and NOx emissions, although emissions of soot, HC, CO, CH2O, N2O, and NO2 are amplified after ammonia blends. Notably, N2O emissions have an impact on the greenhouse effect that is 298 times higher than that of CO2, necessitating attention to N2O emissions. Finally, the study identifies a premixed 40% natural gas/60% ammonia ratio as the optimal blend to effectively mitigate knock combustion and promote near zero carbon emissions from the engine.
Article
Chemistry, Physical
A. Elyanov, V Golub, V. Volodin
Summary: An experimental and analytical study was conducted to investigate the burning characteristics of hydrogen-air mixtures with different concentrations in channels with central and peripheral ignition. The results showed that peripheral ignition resulted in an increased flame propagation speed and a shorter time to reach maximum pressure. An analytical model was developed to describe the flame dynamics in both cases. The findings could be applied to the design of hydrogen-fueled engines with reduced knock-effect.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Energy & Fuels
Jinlu Huo, Yuanhang Guan, Meng Zhang, Duo Zhang, Jiubin Lyu, Zhen Huang, Dong Han
Summary: Understanding the ignition characteristics of diesel in advanced combustion modes is crucial for achieving efficient diesel combustion. This study investigates the auto-ignition characteristics of diesel spray in three different oxidizing atmospheres. The experimental results show that the auto-ignition tendency and combustion intensity of diesel vary in different oxidizing atmospheres. The effects of ambient temperature, pressure, and injection pressure on ignition delay and combustion delay are also examined.
Article
Thermodynamics
Ram Kishore Sankaralingam, M. Feroskhan, M. Elango, T. M. Yunus Khan, Syed Javed, Rahmath Ulla Baig, Venugopal Thangavel
Summary: Homogeneous charge compression ignition (HCCI) is a promising technology to reduce NOx and soot emissions in compression ignition (CI) engines, but lacks combustion control. Premixed charge compression ignition (PCCI) and reactivity-controlled compression ignition (RCCI) are techniques that use partial homogeneous charge to reduce emissions. PCCI regulates combustion by controlling injection timing, while RCCI uses a combination of low reactive and high reactive fuels for combustion control.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Energy & Fuels
Haitao Lu, Fuqiang Liu, Kaixing Wang, Gang Xu, Henry J. Curran
Summary: A semi-detailed mechanism was used to calculate the minimum ignition energy (MIE) of methane-air mixtures using ANSYS Fluent software in this paper. The effects of isothermal and adiabatic wall conditions, equivalence ratio, and electrode wall temperature on the MIE were numerically investigated, showing significant differences in MIE predictions. The numerical results were considered to be considerably more accurate for different equivalence ratios compared to previous studies.
Article
Engineering, Chemical
Mazar A. Shaikh, Vimal R. Patel
Summary: The study aimed to prepare a highly soluble and stable diesel-ethanol-nanoparticle blend for CI engine and investigate the effects of different mixing parameters on ethanol solubility in diesel and nanoparticle stability in diesel-ethanol blends.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2022)
Article
Thermodynamics
A. Vijin Prabhu, Avinash Alagumalai, Amin Jodat
Summary: Artificial neural network (ANN) is widely used for mathematical modeling and prediction, with Levenberg-Marquardt backpropagation training algorithm effectively mapping actual and predicted values to determine engine performance and emission parameters. The study shows that developed ANN models have higher correlation coefficients and lower mean square errors, providing an efficient way to optimize performance and emission parameters.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Energy & Fuels
Binbin Wang, Chuanlei Yang, Hechun Wang, Deng Hu, Yinyan Wang
Summary: This study investigates the effect of varying ammonia blending hydrogen ratio on the combustion performance of a diesel engine. The results show that a 30% hydrogen blending ratio leads to increased explosion pressure, improved power, reduced fuel consumption, and decreased ammonia escape and soot emissions.
Article
Chemistry, Physical
Ratna Kishore Velamati, Sathyajith Raj, P. Parthasarathy, Jithin Edacheri Veetil
Summary: Hot surface ignition of combustible gas mixtures is a safety concern in many engineering applications. This study investigates the impact of heating rates, wire diameters, mixture inlet velocities, and mixture equivalence ratios on the ignition threshold using numerical simulations. The results show that ignition occurs mainly at the rear stagnation point, and the wire heating rate has minimal influence on the ignition phenomenon. However, the ignition threshold increases with higher mixture inlet velocities and equivalence ratios, while it decreases with larger wire diameters. The study also examines the role of local equivalence ratios and reaction rates in understanding the ignition process under different conditions.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
