Article
Physics, Applied
Pengji Ding, Maria Ruchkina, Davide Del Cont-Bernard, Andreas Ehn, Deanna A. Lacoste, Joakim Bood
Summary: Using femtosecond two-photon absorption laser-induced fluorescence technique, the temporal dynamics of the spatial distribution of atomic hydrogen and oxygen in a lean methane-air flame driven by a nanosecond repetitively pulsed discharge-induced plasma were investigated. The study revealed that during the discharge process, excited state hydrogen atoms were detected at the flame front rather than ground state atoms, and the fluorescence intensities of H and O remained constant during a 100 µs cycle between two discharge pulses. Finally, the decay time of O-atoms produced by the discharge in the fresh methane-air mixture was found to be approximately 2 µs, indicating a faster reaction between O-atoms and methane compared to in air.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Optics
Abba Saleh, Piotr Ryczkowski, Goery Genty, Juha Toivonen
Summary: Real-time monitoring of flue gas parameters in combustion processes is crucial for improving process efficiency and reducing pollutant emissions. This study demonstrates simultaneous measurement of water vapor temperature and concentration in an industrial boiler using a broadband lidar, achieving excellent agreement with reference measurements. By utilizing backscattering from aerosol particles, the study also maps the water vapor concentration profile in the boiler, offering new perspectives for 3D profiling of temperature and gas concentration in industrial environments.
Article
Physics, Fluids & Plasmas
F. Sigeneger, J. Ellis, J. Harhausen, N. Lang, J. H. van Helden
Summary: A self-consistent fluid model has been developed and employed to model an electron cyclotron resonance driven hydrogen plasma at low pressure. The model provides key insights into the mutual interaction of microwave propagation, power density, plasma generation, and species transport. Verification experiments demonstrate good agreement with measured ion current density, floating potential, and atomic hydrogen density, confirming the validity of the simulation.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Thermodynamics
Li Fei, Bing-Bing Zhao, Yi Chen, Li-Ming He, Zi-Chen Zhao, Jian-Ping Lei
Summary: Plasma-assisted combustion can improve the performance of aero-engine combustion chambers by increasing combustion efficiency and enhancing combustion chamber stability.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2021)
Article
Physics, Applied
Siyin Zhou, Yiheng Tong, Zhi Zheng, Wansheng Nie, Yunfan Yang, Xiang Liu
Summary: The burst mode is capable of controlling flow and combustion while saving discharge energy compared to continuous mode. Increasing control frequency and duty cycle is favorable for flame stabilization, but too low frequency or duty cycle may lead to unstable flames.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Thermodynamics
Mohammad Shahsavari, Alexander A. Konnov, Agustin Valera-Medina, Mehdi Jangi
Summary: This study investigates the effects of nanosecond plasma discharges on the combustion characteristics of ammonia. The results show that the impact of plasma on ammonia combustion changes by altering the reduced electric field value. The plasma is most effective in the medium range of reduced electric field. An increase in pulse energy density can decrease the ignition delay time and increase the laminar flame speed. Using He as the diluent in the oxidizer can produce more radicals, electronically excited and charged species. The thickness of the ammonia flame is minimum at a critical pulse energy density.
COMBUSTION AND FLAME
(2022)
Article
Energy & Fuels
Christian Meissner, Henrik Schneider, Evaggelos Sidiropoulos, Jonas Hoelzer, Tim Heckmann, Benjamin Boehm, Andreas Dreizler, Thomas Seeger
Summary: This study focused on the wall and gas phase temperatures inside a swirled oxy-fuel combustion chamber, comparing different methods such as vibrational CARS and rotational CARS for gas phase temperature measurements. The developed O-2-VCARS system was successfully tested in a harsh environment to provide a measurement tool for gas-assisted pulverized solid fuel flames, with discussions on possible error sources related to particles within the probe volume.
Article
Thermodynamics
L. Cheng, N. Barleon, B. Cuenot, O. Vermorel, A. Bourdon
Summary: This paper presents the research progress on plasma assisted combustion, focusing on key aspects such as fast gas heating, slow gas heating, and radical production. An incremental methodology is used to build a single plasma mechanism, and its validity is verified through experimental validation. The rates of critical reactions for nitrogen quenching are discussed, and the mechanism is simplified for multi-dimensional simulations.
COMBUSTION AND FLAME
(2022)
Article
Metallurgy & Metallurgical Engineering
Zhe Zhang, Xing Jin, Wen-xiong Xi
Summary: The study analyzed the combustion characteristics under different injection conditions, revealing that an increase in total pressure of strut fuel injection leads to a decrease in combustion efficiency. However, increasing the total pressure of strut fuel injection within a proper range can expand the combustion area downstream. Increasing the total pressure of cavity fuel injection within the range of 0.5-2.0 MPa expands the combustion range and improves combustion efficiency, but excessive total injection pressure of cavity fuel can result in a sharp drop in efficiency. Increasing the total injection pressure of the plasma jet raises the height of the cavity shear layer and improves the equivalence ratio of the gas mixture in the cavity, with a maximum combustion efficiency of 82.1% achieved at a total pressure of 1.25 MPa. The combustion-assisted effect of different plasma jet media varies significantly, with O2 having the most significant effect on the combustor.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2021)
Article
Thermodynamics
Praise N. Johnson, Taaresh S. Taneja, Suo Yang
Summary: The Global Pathway Analysis (GPA) algorithm is extended to plasma-assisted combustion and fuel reforming systems in order to identify dominant global pathways and reaction cycles involving high-concentration species. The newly developed Plasma-based Global Pathway Analysis (PGPA) algorithm considers element-flux transfer, heat release, and radical production rate to evaluate the reactivity of identified pathways and cycles. PGPA analysis provides valuable insights into the kinetics of plasma-assisted systems, such as the reactivity of NH3/air mixtures and the production of NO.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Jinhoon Choe, Wenting Sun, Timothy Ombrello, Campbell Carter
Summary: This study demonstrates that plasma can reduce NOx emissions and extend the lean blowoff limits of ammonia flames, in contrast to previous research using hydrocarbon fuels. These findings could pave the way for practical application of plasma in ammonia combustion.
COMBUSTION AND FLAME
(2021)
Article
Physics, Fluids & Plasmas
E. Bisceglia, S. Prasanna, K. Gazeli, X. Aubert, C. Y. Duluard, G. Lombardi, K. Hassouni
Summary: A nanosecond-two-photon absorption laser-induced fluorescence technique was used to investigate the transients of a pulsed microwave discharge, demonstrating its validity for monitoring nitrogen atom densities. Unexpectedly, there was a 10% increase in N(S-4) atom density during the transition from high- to low-power phases. A detailed analysis of the nitrogen atom kinetics attributed this enhancement to surface de-excitation of N(D-2) and N(P-2) atoms.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2021)
Article
Thermodynamics
Leonardo Castellanos, Francesco Mazza, Alexis Bohlin
Summary: We propose a novel diagnostic technique to measure water vapor concentration in hydrogen combustion environments using time-resolved coherent anti-Stokes Raman scattering (CARS) signal of nitrogen (N2). Our technique allows for absolute concentration measurements of major species in H2 flames, providing a comprehensive characterization of flow composition and temperature field.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Optics
Elijah R. Jans, Darrell J. Armstrong, Arlee Smith, Sean P. Kearney
Summary: This paper demonstrates the broadband nanosecond coherent anti-Stokes Raman scattering (CARS) using a burst-mode pumped noncolinear optical parametric oscillator (NOPO) with a pulse repetition rate of 40 kHz. The NOPO is pumped by a burst-mode Nd:YAG laser at 50 mJ/pulse for 45 pulses, producing an output centered at around 607 nm, with a bandwidth of 370 cm-1 at 5 mJ/pulse. A planar BOXCARS phase matching scheme is used for single-laser-shot nitrogen thermometry in near adiabatic H2/air flames at temperatures up to 2200 K, with the broadband NOPO output as the Stokes beam and the narrowband 532-nm burst-mode output as the two CARS pump beams.
Article
Computer Science, Information Systems
Francesco Malandrino, Carla Fabiana Chiasserini, Gian Michele Dell'Aera
Summary: In this work, we propose an assisted driving system that leverages the synergy between connected vehicles and the edge of the network infrastructure to effectively drive local decisions based on global traffic policies. We integrate different entities within an edge-based architecture to share information and make decisions at different time scales. Using a queuing-based model and optimization problem formulation, we develop an iterative algorithm called Bottleneck Hunting (BH) to make global decisions on traffic flows. Our solution demonstrates significant reductions in travel times compared to traditional approaches.
IEEE TRANSACTIONS ON MOBILE COMPUTING
(2023)
Article
Physics, Fluids & Plasmas
Caleb Richards, Elijah Jans, Ilya Gulko, Keegan Orr, Igor Adamovich
Summary: In this study, the vibrational and translational-rotational temperatures in quasi-two-dimensional atmospheric pressure plasma jets sustained by ns pulse and RF discharges in nitrogen/noble gas mixtures were measured using broadband vibrational Coherent Anti-Stokes Raman Scattering (CARS). The results show that the RF plasma jets have stronger vibrational excitation compared to the ns pulse discharge, and the vibrational temperature in the ns pulse discharge is affected by the presence of helium atoms. The experimental data in the RF plasma jet in N-2/Ar are compared with kinetic modeling predictions.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
Xin Yang, Elijah Jans, Caleb Richards, Sai Raskar, Dirk van den Bekerom, Kai Wu, Igor Adamovich
Summary: This study examines the role of the electronic excited states of N-2(A(3)Sigma(+)(u)) molecules in the dissociation of N2 in plasmas. It is found that energy pooling in collisions between N-2(A(3)Sigma(+)(u)) molecules plays a major role in N2 dissociation. Additionally, the rapid quenching by H atoms leads to a significant reduction in N-2(A(3)Sigma(+)(u)) populations and the rate of N atom generation.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Thermodynamics
Yong Tang, Qiang Yao, Marien Simeni Simeni, Igor V. Adamovich
Summary: This study investigates the response of counterflow diffusion flames to sub-breakdown DC and AC electric fields, as well as their superposition with ns pulse discharge waveforms in the plane-to-plane electrode geometry. The results show that sub-breakdown DC and low-frequency AC electric fields displace the flame towards the grounded electrode. However, as the AC frequency increases, the flame response becomes less pronounced. Combining a nanosecond pulse discharge with a sub-breakdown DC field generates a diffuse plasma across the entire gap. The rapid plasma self-shielding in the plane-to-plane geometry prevents the detectable flame displacement enhancement observed in other electrode geometries.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
E. R. Jans, I. W. Jones, X. Yang, T. A. Miller, J. F. Stanton, I. Adamovich
Summary: The time-resolved, absolute HO2 number density in different mixtures excited by pulsed discharge was measured by CRDS, showing good agreement with the spectral model. The persistence of HO2 in the afterglow of the H-2-O-2 mixture at high temperatures suggests that plasma excitation may impact low-temperature fuel oxidation and reforming.
COMBUSTION AND FLAME
(2022)
Article
Physics, Applied
I Adamovich, S. Agarwal, E. Ahedo, L. L. Alves, S. Baalrud, N. Babaeva, A. Bogaerts, A. Bourdon, P. J. Bruggeman, C. Canal, E. H. Choi, S. Coulombe, Z. Donko, D. B. Graves, S. Hamaguchi, D. Hegemann, M. Hori, H-H Kim, G. M. W. Kroesen, M. J. Kushner, A. Laricchiuta, X. Li, T. E. Magin, S. Mededovic Thagard, V Miller, A. B. Murphy, G. S. Oehrlein, N. Puac, R. M. Sankaran, S. Samukawa, M. Shiratani, M. Simek, N. Tarasenko, K. Terashima, E. Thomas, J. Trieschmann, S. Tsikata, M. M. Turner, I. J. van der Walt, M. C. M. van de Sanden, T. von Woedtke
Summary: The 2022 Roadmap is a publication that aims to identify important challenges in the field of low-temperature plasma (LTP) physics and technology. It includes visions from 41 leading experts representing 21 countries and five continents, with a focus on new topics and areas of interest in the field. The roadmap is expected to contribute to the continued development of LTP science and technology in the next 5-10 years.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
S. Raskar, K. Orr, I. Adamovich, T. L. Chng, S. M. Starikovskaia
Summary: Using non-collinear pump laser beam arrangements, the spatial resolution of EFISH generation has been improved, allowing for measurements of electric field distributions in high-pressure plasmas. This approach provides better accuracy and precision compared to collinear pump laser beam arrangements.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
Dirk van den Bekerom, Caleb Richards, Erxiong Huang, Igor Adamovich, Jonathan H. Frank
Summary: Researchers have developed a new diagnostic technique for quantitative 2D imaging of methyl profiles in plasma. This technique allows for temporal and spatial measurements of methyl distributions, which are important for studying plasma-surface interactions. The technique involves photo-dissociation of methyl and absolute calibration using a gas mixture, and has been successfully applied to imaging and measuring methyl production in different plasma conditions.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
Hongtao Zhong, Xin Yang, Xingqian Mao, Mikhail N. Shneider, Igor Adamovich, Yiguang Ju
Summary: This study investigates the stability of plasma in reactive mixtures, focusing on the thermal-chemical instability triggered by dimethyl-ether (DME) low-temperature oxidation. Through experimental exploration and theoretical analysis, the dynamics and chemical origin of the instability are revealed, providing insights for future control of plasma uniformity.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
Caleb Richards, Elijah Jans, David Mignogna, Igor Adamovich
Summary: Investigated the relationship between CO generation and vibrational energy levels in CO2-N2 plasma, and found that CO2 dissociation caused by vibrational excitation is insignificant under current conditions;The rate of CO generation decreases gradually during the discharge burst, unrelated to the vibrational temperatures of N2 and CO2;During the later half of the discharge burst and in the afterglow, the vibrational temperatures of N2 and CO2 decrease rapidly.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
Hamzeh Telfah, Elijah Jans, Sai Raskar, Igor Adamovich
Summary: In this study, the generation and decay of HO2 radicals were investigated using CRDS technique, providing insights into the formation and consumption pathways of HO2 in plasma-liquid interactions.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
Martina Mrkvickova, Lucia Kuthanova, Petr Bilek, Adam Obrusnik, Zdenek Navratil, Pavel Dvorak, Igor Adamovich, Milan Simek, Tomas Hoder
Summary: We studied the development of electric field in weak microseconds-lasting atmospheric pressure Townsend discharge in pure nitrogen using four different methods. These methods include laser-aided electric field induced second harmonics (EFISH), optical emission-based first negative/second positive systems (FNS/SPSs) intensity ratio, electrical equivalent circuit approach, and determination of the Townsend first coefficient a(E/N) from the spatial optical emission profile. The values of the electric field obtained from these methods, regardless of absolute differences, fall within a reasonable range. The limitations and advantages of each method are discussed in detail, and potential future steps for improvement are identified.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
Xin Yang, Caleb Richards, Igor Adamovich
Summary: Plasma-catalytic ammonia synthesis in both ns pulse discharge and 'hybrid' ns pulse/RF discharge were studied using Fourier Transform infrared absorption spectroscopy. The results show that the ammonia yield in the plasma-catalytic reactor is controlled by the N atom accumulation on the catalyst surface and the reaction with H atoms. Additionally, the ammonia yield is increased by approximately 20% with the addition of the RF waveform compared to the baseline ns pulse discharge conditions, regardless of the presence of catalyst.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
Brian N. Bayer, Sai Raskar, Igor Adamovich, Peter J. Bruggeman, Aditya Bhan
Summary: The production and loss of vibrationally excited nitrogen molecules are analyzed to understand their role in ammonia formation by plasma catalysis. It is found that the loss of vibrationally excited nitrogen due to surface-mediated relaxation limits its contribution to catalytic ammonia formation.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Correction
Physics, Fluids & Plasmas
Caleb Richards, Elijah Jans, Ilya Gulko, Keegan Orr, Igor Adamovich
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Thermodynamics
Elijah R. Jans, Ilya Gulko, Dirk C. M. van den Bekerom, Terry A. Miller, Igor Adamovich
Summary: Nonintrusive laser diagnostics were used to measure the populations of metastable nitrogen molecules in a nonequilibrium flow. Different diagnostic techniques were employed, including tunable diode laser absorption spectroscopy (TDLAS) and cavity ring down spectroscopy (CRDS), for characterizing the flow properties under different pressures.
JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER
(2022)