Article
Thermodynamics
Sergio Martinez, Mohammadreza Baigmohammadi, Vaibhav Patel, Snehasish Panigrahy, Amrit B. Sahu, Shashank S. Nagaraja, Ajoy Ramalingam, A. Abd El-Sabor Mohamed, Kieran P. Somers, Karl A. Heufer, Andrzej Pekalski, Henry J. Curran
Summary: This work investigates the ignition delay time characteristics of C-2-C-3 binary blends and validates the chemical kinetic model NUIGMech1.1 through experiments. The results show that the model agrees with experimental data within approximately 26.4% under all conditions studied, with sensitivity and flux analyses helping to identify key reactions controlling the ignition behavior of the blends.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
P. Morsch, Y. Fenard, K. A. Heufer
Summary: Ethyl butanoate is studied as a representative of oxygenated hydrocarbons for potential use as future liquid fuels. Experimental results show a negative temperature coefficient regime with ignition delay times increasing with temperature. Comparison of molecular structures provides insights for future fuel design.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Khaiyom Hakimov, Yang Li, S. Mani Sarathy, Jihad Badra, Emre Cenker, Aamir Farooq
Summary: Ignition delay times (IDTs) of iso-octane/air mixture were measured at different conditions. The study found that IDTs were longer at lower equivalence ratio and shorter at higher pressures. Existing chemical kinetic models showed notable differences compared to the experimental data at fuel-lean conditions, and modifications were made based on sensitivity analyses to improve model performance.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Shijun Dong, Christopher Aul, Claire Gregoire, Sean P. Cooper, Olivier Mathieu, Eric L. Petersen, Jose Rodriguez, Fabian Mauss, Scott W. Wagnon, Goutham Kukkadapu, William J. Pitz, Henry J. Curran
Summary: The low-temperature chemistry of 1-hexene was studied, and a new detailed chemical kinetic model was proposed and validated. The auto-ignition behavior and oxidation processes of 1-hexene at various conditions were predicted well by the kinetic model. Analysis showed that reactions associated with hydroxy radical addition to the double bond contribute most to the low-temperature reactivity of 1-hexene.
COMBUSTION AND FLAME
(2021)
Article
Energy & Fuels
Feng Zhang, Hong-yu Chen, Jian-chang Feng, Dong Zheng
Summary: In this study, ignition delay times of N2O-C2H4 propellants were measured under specific conditions and an expression was derived to predict ignition delays. The analysis showed that at high temperatures, N2O decomposition reaction has the highest sensitivity coefficient, while at low temperatures, oxidation reactions of N2O and hydrocarbons become more important. Further development of low-temperature oxidation mechanism is needed for better prediction of low-temperature ignition behaviors.
Article
Chemistry, Physical
Ziyu Wang, Chao Yan, Bowen Mei, Ying Lin, Yiguang Ju
Summary: This study investigates the oxidation of diethyl ether (DEE) under low-temperature and ultra-high-pressure conditions. The experimental data shows that DEE exhibits unusual low-temperature oxidation behavior with two negative temperature coefficient (NTC) zones. Increasing the pressure stabilizes RO2 and promotes HO2 chemistry, resulting in weaker NTC zones. The existing DEE model is updated to improve the predictability of key species, especially at intermediate temperature.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Energy & Fuels
Zhongjun Wan, Lei Shi, Dongdong Chen, Ping Li, Changhua Zhang
Summary: In this study, the effects of n-butanol on the auto-ignition of toluene reference fuel have been investigated. It was found that n-butanol promotes the auto-ignition of toluene at high temperatures, but inhibits it at low temperatures. A reliable mechanism for n-butanol/toluene reference fuel has been developed and validated through calculations and experiments. The dominant chain propagating reactions were identified, and an inhibiting reaction at low temperatures was also discovered.
Article
Thermodynamics
P. Morsch, M. Doentgen, K. A. Heufer
Summary: Although biodiesel fuels derived from esters are widely discussed and used, there is still insufficient understanding of the combustion process, particularly for ethyl esters. This study aimed to enhance both experimental data and theoretical knowledge by measuring ignition delay times and performing quantum chemical calculations. The results contribute to the validation of kinetic modeling and provide insights into the low-temperature chemistry and the influence of the ester moiety.
COMBUSTION AND FLAME
(2022)
Article
Energy & Fuels
Wei-Cheng Wang, Akhmad Faruq Alhikami, Chia-En Yao
Summary: The combustion characteristics of conventional and renewable jet fuels at low-to-intermediate temperatures were studied, showing that leaner fuel/oxidizer mixture conditions resulted in longer auto-ignition delays. Increasing compression pressures led to shorter auto-ignition delays. The negative temperature coefficient regime was strongly influenced by changes in equivalence ratio. The renewable jet fuel exhibited shorter auto-ignition delays compared to petroleum jet fuels, attributed to its higher hydrogen-to-carbon ratio and lower concentration of cyclic molecules.
Article
Energy & Fuels
Trupti Kathrotia, Patrick Osswald, Julia Zinsmeister, Torsten Methling, Markus Koehler
Summary: This study investigates the molecular structure and chemical reactivity of various hydrocarbons and aviation fuels through simulation and experimental methods. By employing detailed fuel surrogates and high temperature reaction kinetic mechanism, it explores the impact of fuel surrogate components on the formation of fuel intermediates.
Article
Thermodynamics
Yebing Mao, Liang Yu, Yong Qian, Sixu Wang, Zhiyong Wu, Mohsin Raza, Lei Zhu, Xiaobing Hu, Xingcai Lu
Summary: This study proposed a kinetic model for RP-3 aviation fuel, formulated a surrogate containing four key components using genetic algorithm and local search method, and successfully simulated the properties and combustion behavior of RP-3 fuel.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Chao Peng, Chun Zou, Wenxiang Xia, Qianjin Lin, Jianghui Luo, Haiyang Shi, Lixin Lu, Shusen Wang
Summary: Pressurized oxy-fuel combustion is considered an advanced technique with lower cost and little decrease in efficiency compared to conventional PC systems without CO2 capture. Experimental and modeling work on n-butane ignition delay times under different conditions validates the updated chemical kinetic model Oxymech2.0 Plus, which shows improved prediction accuracy for butane combustion in O2 / CO2 atmospheres. The effects of equivalence ratios and CO2 concentrations on the ignition delay times of n-butane were analyzed.
COMBUSTION AND FLAME
(2021)
Article
Energy & Fuels
Ashish Shah, Song Cheng, Douglas E. Longman, S. Scott Goldsborough, Toby Rockstroh
Summary: The study experimentally investigated the uncertainties associated with parameters required for the Livengood-Wu (LW) integral method when used for model-based control of ignition timing in advanced compression ignition (ACI) engines, finding that the uncertainty in cylinder charge temperature has the greatest influence on the predicted time of ignition. Proposed improved methods of estimating cylinder charge temperature to enable the use of the LW integral method for model-based control of ignition timing.
Article
Energy & Fuels
Jing Li, Jizhen Zhu, Sixu Wang, Yuan Feng, Wei Zhou, Yong Qian, Liang Yu, Xingcai Lu
Summary: Gasoline compression ignition (GCI) has been studied extensively due to its high efficiency and low emissions. This study focused on the autoignition chemistry of low-octane gasoline fuels with different research octane numbers (RON) using a rapid compression machine (RCM). The results showed that the low-octane gasolines exhibited two-stage ignition characteristics with negative temperature coefficient (NTC) behavior in the low-to-intermediate temperature range. Additionally, under simulated exhaust gas recirculation (EGR) conditions, it was found that the NTC region shifted towards higher temperatures with decreasing oxygen concentration.
Article
Energy & Fuels
Seunghyeon Lee, Soonho Song
Summary: The study found that the addition of hydrogen has an impact on the ignition delay time of methyl butanoate, with varied effects depending on the temperature. At low temperatures, hydrogen addition increases ignition delay, while decreasing it at high temperatures.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Thermodynamics
J. Herzler, S. A. Mujaddadi, M. Fikri, C. Schulz, S. Peukert
Summary: Single-pulse shock-tube experiments were conducted to investigate the thermal decomposition of selected oxygenated hydrocarbons. Gas chromatography/mass spectrometry (GC/MS) was used to measure reactant consumption and stable product formation. The results showed that these reactants primarily decompose through six-center eliminations.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Engineering, Environmental
Mohaned Hammad, Steven Angel, Ahmed K. Al-Kamal, Anam Asghar, Amin Said Amin, Mena-Alexander Kraeenbring, Haakon T. A. Wiedemann, Vineetha Vinayakumar, Md Yusuf Ali, Paolo Fortugno, Cheolyong Kim, Torsten C. Schmidt, Christopher W. M. Kay, Christof Schulz, Doris Segets, Hartmut Wiggers
Summary: This study develops a scalable method to synthesize stable and environmentally-friendly LaCoO3/graphene nanocomposites for the removal of organic pollutants from wastewater. The catalyst exhibits outstanding catalytic degradation of various pollutants and excellent reusability and pH adaptability. The formation of composites prevents cobalt leaching and enhances the catalytic activity. The results suggest that LaCoO3/graphene is a promising material for environmental remediation.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Sascha Apazeller, Munko Gonchikzhapov, Monika Nanjaiah, Tina Kasper, Irenaus Wlokas, Hartmut Wiggers, Christof Schulz
Summary: A new burner has been developed for spray-flame synthesis, enabling observation and modeling of reaction processes with precise control and homogeneity. The burner provides a laminar and steady flame, allowing investigation of reactions independent of spray formation and turbulent mixing. It also allows the use of reactants that would otherwise react before reaching the flame. Experimental data and simulations using a reduced reaction mechanism demonstrate the suitability of the burner for modeling precursor reactions in spray-flame synthesis.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
D. Nativel, S. Peukert, J. Herzler, A. Drakon, M. Korshunova, E. Mikheyeva, A. Eremin, M. Fikri, C. Schulz
Summary: The effects of various oxygenated co-reactants on the formation of soot during the pyrolysis of gas mixtures containing ethylene as a base fuel were studied. Alcohols (methanol, ethanol, and n-butanol) and ethers (diethyl ether, dimethoxymethane, furan, and tetrahydrofuran) were used as the oxygenated co-reactants. The pyrolysis process was investigated using laser extinction and time-resolved spectroscopy techniques. The results showed that only methanol did not promote soot formation, while the addition of other oxygenated hydrocarbons increased soot yields. Simulations based on a detailed chemical kinetics mechanism provided qualitative insights into the experimental results, revealing that the promotion of soot formation by oxygenated co-reactants was related to the release of CH3 and C3H3 during thermal decomposition, leading to accelerated formation of C6H6 rings.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Sadrollah Karaminejad, Sophie M. L. Dupont, Malte Bieber, Manuel A. Reddemann, Reinhold Kneer, Thomas Dreier, Torsten Endres, Christof Schulz
Summary: The temporal flame stability is an important parameter for spray-flame synthesis of nanoparticles. This study investigates the influence of different nozzle geometries on the flame stability of the SpraySyn burner. The converging geometry of the modified nozzle leads to smaller droplets and enhanced evaporation, resulting in a more stable flame.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Markus Michael Prenting, Seung-Jin Baik, Thomas Dreier, Torsten Endres, Andreas Kempf, Christof Schulz
Summary: The SpraySyn burner uses a combustible liquid containing metal salts and molecular oxygen to generate oxide nanoparticles. The burner has a simple design that allows for accurate simulation and model development. The burner utilizes a methane/oxygen flat flame for stability.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Chemistry, Physical
Damien Nativel, Can Shao, Sean P. Cooper, Eric L. Petersen, Christof Schulz, Mustapha Fikri, Sebastian Peukert
Summary: The influence of methanol and butanol on soot formation during the pyrolysis of a toluene primary reference fuel mixture was investigated. It was found that soot formed during the pyrolysis is primarily caused by the thermal decomposition of toluene. Adding methanol results in a slight reduction of soot formation, while adding butanol shifts the soot formation to higher temperatures without overall reduction.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Optics
Guannan Liu, Patrick Wollny, Jan Menser, Thomas Dreier, Torsten Endres, Irenaeus Wlokas, Kyle J. Daun, Christof Schulz
Summary: This study presents an approach to determine the location of the liquid-to-solid phase transition and the volume fraction and number density of particles of both phases within a gas phase reactor. Spectrally-resolved line-of-sight attenuation measurements are applied to a silicon nanoparticle aerosol generated from monosilane in a microwave plasma reactor. The approach was applied to analyze spatially and spectrally resolved measurements from the hot gas flow downstream of the plasma zone where both solid and liquid silicon particles coexist.
Article
Optics
M. Lubnow, T. Dreier, C. Schulz, T. Endres
Summary: This study demonstrates high-repetition-rate imaging of liquid-film thickness resulting from impinging water droplets on a glass surface. The absorption at two near-infrared wavelengths was detected using a high-frame-rate InGaAs focal-plane array camera, achieving frame rates of 1 kHz and measurement rates of 500 Hz.
Article
Engineering, Environmental
P. Wollny, L. Engelmann, M. Loewenich, I. Rahinov, H. Wiggers, C. Schulz, A. Kempf, I. Wlokas
Summary: A novel Eulerian particle model tailored for CFD applications is introduced, which is based on a bivariate moment method and features a full coupling with the gas-phase through kinetic formulations. The model is applied in the context of silicon nanopowder synthesis from monosilane and validated with a hot-wall reactor experiment.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Martin Underberg, Markus M. Prenting, Moritz Sieber, Sebastian Schimek, Christian O. Paschereit, Tim Huelser, Torsten Endres, Christof Schulz, Hartmut Wiggers, Sophie Marie Schnurre
Summary: This paper presents a nanoparticle synthesis method based on spray combustion and a novel burner concept. The burner can be operated to control the properties and yield of nanoparticles, while improving the sustainability of the fuel. It is found that the combustion temperature plays a crucial role in the kinetics of precursor decomposition, particle formation, and growth.
APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE
(2023)
Article
Thermodynamics
Ahmad Saylam, Torsten Endres, Christof Schulz
Summary: Premixed flat flames are used to investigate soot formation through optical diagnostics. The influence of burner geometry and shielding on the flame is studied using simulations and measurements. The results show that species diffusion and heat transfer have a significant impact on the temperature and species concentration profiles, especially under near-threshold sooting conditions.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Matthieu R. Lalanne, Sheikh Ahmed Mujaddadi, Peter Fjodorow, Sergey Cheskis, Holger Somnitz, Irenaeus Wlokas, Jurgen Herzler, Mustapha Fikri, Christof Schulz, Igor Rahinov
Summary: The reaction between Fe atoms and O2 in a mixture of IPC and oxygen has been studied using a combination of ARAS and ICAS methods. FeO was found to be present at temperatures below 1400K, leading to a reassessment of rate coefficients for different Fe oxidation channels.
APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE
(2023)
Article
Thermodynamics
Monika Nanjaiah, Patrick Wollny, Praveen Narasu, Sascha Apazeller, Sadrollah Karaminejad, Torsten Endres, Hartmut Wiggers, Christof Schulz, Eva Gutheil, Andreas Kempf, Irenaeus Wlokas
Summary: A novel matrix burner was used to study aerosol-doped laminar low-pressure flames. The aerosol state entering the flame front was quantified and thermal losses and buoyancy effects were simulated. The experimental setup was validated for reaction kinetics investigations and a hypothesis about the origin of gas-borne nanoparticles was derived.
APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE
(2023)
Article
Thermodynamics
Paolo Fortugno, Claudia-Francisca Lopez-Camara, Fabian Hagen, Hartmut Wiggers, Christof Schulz
Summary: In this study, the effects of carbon dioxide, molecular oxygen, and nitrous oxide on the carbon-to-oxygen (C/O) ratio and carbon microstructure in the microwave-plasma synthesis of few-layer graphene from hydrocarbon precursors were investigated. The results showed that molecular oxygen and nitrous oxide increased the graphene fraction with decreasing C/O ratios, while pure graphene was achieved at a C/O ratio of 2:1.5. However, carbon dioxide could not generate pure graphene at the same C/O ratio. Emission spectroscopy indicated that carbon dioxide formed carbon species during plasma decomposition, suggesting a potential influence on local carbon nucleation.
APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE
(2023)
