Article
Thermodynamics
Yacine Bechane, Benoit Fiorina
Summary: Nanosecond Repetitively Pulsed (NRP) discharges are an efficient way to promote turbulent flame ignition, inducing ultra-fast species dissociation and heating phenomena. Computational simulations show that atomic O produced during the discharge process can enhance methane oxidation reactions, reducing the combustion chemistry time scale and increasing ignition success.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Physics, Applied
Francesco Di Sabatino, Thibault F. Guiberti, Jonas P. Moeck, William L. Roberts, Deanna A. Lacoste
Summary: The study found that different strategies of plasma actuation have varying effects on flame anchoring under different pressure conditions. High applied voltage and low pulse repetition frequency are preferable at atmospheric pressure, while the opposite is observed at elevated pressures. Additionally, a ratio of plasma power to thermal power of the flame around 1% is found to be the best compromise between a strong actuation of the flame and a reasonable deposited electrical power.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Thermodynamics
Ammar M. Alkhalifa, Abdulrahman Alsalem, Davide Del Cont-Bernard, Deanna A. Lacoste
Summary: This study investigated the use of nanosecond repetitively pulsed (NRP) glow discharges to mitigate thermoacoustic fluctuations. Two strategies, continuous forcing and closed-loop gated forcing, were compared and found effective in reducing thermoacoustic fluctuations in a wall-stabilized methane-air flame. A parametric study was conducted to analyze the impact of various factors on the performance of the plasma actuator. The study also utilized phase-locked imaging to observe the oscillations in the flame's base location and surface area and demonstrated the stability achieved with the optimal discharge forcing.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Liang Yu, B. Aravind, Deanna A. Lacoste
Summary: This paper demonstrates that nanosecond repetitively pulsed discharges can reduce the response of lean methane-air swirl flames to acoustic excitations at pressures up to 3 bar. The flame transfer functions with and without plasma discharges were studied in the frequency range of 48-380 Hz at pressures of 1.2, 2.0, and 3.0 bar. The results show that the plasma discharges can decrease the gain of the flame transfer functions by up to 50%, regardless of the pressure. The mechanisms responsible for this effect are discussed.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Yacine Bechane, Benoit Fiorina
Summary: Experimental studies have shown that Nanosecond Repetitively Pulsed (NRP) discharges can efficiently improve flame stability in lean regimes by generating a non-equilibrium plasma that induces local heating and production of active species. This study aims to understand the physical and chemical mechanisms involved in plasma-assisted turbulent combustion. High-performance computations of a lean bluff-body turbulent premixed methane-air flame are conducted by combining a semi-empirical plasma model with an analytical combustion mechanism. The results demonstrate that the plasma assistance significantly enhances flame power and surface, leading to increased chemical reactivity and heat release rate.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Guillaume Vignat, Nicolas Minesi, Preethi Rajendram Soundararajan, Daniel Durox, Antoine Renaud, Victorien Blanchard, Christophe O. Laux, Sebastien Candel
Summary: Plasma-Assisted Combustion (PAC) shows potential in improving ignition, extinction, and dynamic performance of combustion systems. Nanosecond Repetitively Pulsed (NRP) spark discharges are used to extend the lean blow out (LBO) limit of the SICCA-Spray burner by finding the optimal electrode position near the external edge of the outer recirculation zone (ORZ). The results indicate significant improvement in extinction performance with PAC, particularly when operating with liquid fuel spray injection.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Physics, Fluids & Plasmas
N. Q. Minesi, V. P. Blanchard, E. Pannier, G. D. Stancu, C. O. Laux
Summary: This study investigates the effects of nanosecond repetitively pulsed (NRP) discharges in burnt gases, filling a gap in knowledge in this area. The researchers performed quantitative optical emission spectroscopy and measurements of electrical energy deposition to analyze the temperature and concentration variations during the discharge and characterize its properties. These measurements are important for future research, testing discharge kinetic models, and deriving a simplified model of plasma-assisted combustion.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Chengjie Bai, Shi Li, Tong Chen, Xiaoxiao Chen, Wenjing Meng, Jie Pan
Summary: Through numerical investigation, this study examined the effects of inert gas dilution on methane-air NRP discharge plasma ignition process and related reaction mechanisms, showing that the addition of inert gases significantly reduces ignition delays.
Article
Physics, Applied
Xingxing Wang, Adam Patel, Alexey Shashurin
Summary: This study investigates the evolution of discharge parameters in pin-to-pin NRP discharges in air, revealing memory effects at repetition frequencies of 10 and 100 kHz. Significant changes in discharge parameters were observed for 10 kHz NRP discharges, while a new steady-state was reached after five pulses for 100 kHz NRP discharges.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Thermodynamics
Julien Lambert, Sylvain Coulombe, Gilles Bourque, Jeffrey M. Bergthorson
Summary: There has been an increased interest in plasma-assisted combustion due to its ability to improve flame stability and combustion performance over the past two decades. This study investigates the hydrodynamic effect of nanosecond repetitively pulsed discharges on a lean premixed methane-air flame at atmospheric pressure, finding that the plasma pulse repetition frequency impacts flame stability and upstream movement. The plasma reduces flow velocity upstream of the flame front and induces stretch in the flame, resulting in an increase in flame speed.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
M. Balmelli, L. Merotto, P. Soltic, J. Biela
Summary: NRPD is a promising ignition concept for introducing renewable fuels in SI engines, and the methodology presented in this paper allows for the detection of successful ignition and closed-loop ignition control.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Thermodynamics
Joshua A. T. Gray, Deanna A. Lacoste
Summary: This study introduces a method for using NRP plasma discharges to accelerate flame propagation, achieving successful deflagration-to-detonation transition. By locating the plasma near the tube wall to reduce electrode presence and identifying two enhancement mechanisms for flame acceleration, significant progress is made in understanding the process.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Chemistry, Physical
Yongseok Choi, Kyu Tae Kim
Summary: To enable reliable lean-premixed gas turbine combustion with pure hydrogen or high hydrogen content fuels, multi-element injector configurations comprising numerous small-scale jet nozzles are required. The integration of large numbers of millimeter-scale injectors in tightly clustered arrays is likely to produce peculiar topological states determined by the collective dynamics of strongly interacting premixed hydrogen flames. Experimental investigation of two different pure hydrogen flame ensembles reveals that the characteristic dimension of a single injector element is the main determinant of the fundamental frequency of self-induced pressure oscillations, and that flame dynamics play a mechanistic role in the growth of higher harmonics, defining the thermoacoustic state of clustered lean-premixed hydrogen flames.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Thermodynamics
Bayu Dharmaputra, Sergey Shcherbanev, Bruno Schuermans, Nicolas Noiray
Summary: This study demonstrates the effectiveness of Nanosecond Repetitively Pulsed Discharges (NRPD) in stabilizing sequential combustors. Low-power NRPD can successfully suppress instabilities without increasing NO emissions. However, high-power NRPD, while further enhancing stability, significantly elevates NO emissions.
COMBUSTION AND FLAME
(2023)
Article
Physics, Applied
Sergey A. Shcherbanev, Tanguy Krzymuski, Yuan Xiong, Nicolas Noiray
Summary: This study investigates the phenomenon of jetting axial flow induced by nanosecond repetitively pulsed discharges in quiescent ambient air. The direction and generation of the flow are influenced by the discharge parameters and can be controlled by the applied high-voltage pulses. Experimental results and measurements of plasma parameters provide insights into the mechanisms of the axial flow.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Thermodynamics
Vincent Giuffrida, Michele Bardi, Mickael Matrat, Anthony Robert, Guillaume Pilla
Summary: This paper investigates the chemistry of O-3 in a compression ignition engine with Diesel type combustion using 3D CFD simulation. The proposed methodology, which includes 0D and 3D simulations, accurately captures the impact of O-3 on ignition delay and heat release. The study shows that O-3 mainly affects the LTHR phase of the combustion process and does not influence the topology and propagation of the flame inside the combustion chamber.
INTERNATIONAL JOURNAL OF ENGINE RESEARCH
(2022)
Article
Physics, Fluids & Plasmas
Ciprian Dumitrache, Arnaud Gallant, Nelson de Oliveira, Christophe O. Laux, Gabi Daniel Stancu
Summary: This work presents a femtosecond two-photon absorption laser-induced fluorescence (fs-TALIF) diagnostic for measuring ground-state atomic nitrogen in nanosecond repetitively pulsed (NRP) discharges. The technique allows for high spatial and temporal resolution measurements at elevated pressures. The fs-TALIF at high laser intensity regime was found to have a detection limit that is approximately one order of magnitude better than previously reported techniques.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Thermodynamics
Yuan Xiong, Deanna A. Lacoste, Suk Ho Chung, Min Suk Cha
Summary: This paper reports on the effect of DC electric fields on the dynamics of a premixed methane-air laminar flame in a buoyant environment. The suppression of buoyancy-driven flickering oscillations and the response of the flame to acoustic modulation of the flow were investigated. The results showed that applying sub-critical negative DC voltages can suppress the flickering oscillations of the flame. The analysis of the current measured in the inter-electrodes area indicated that it cannot be used as a tracer of heat release rate when the flame location varies with sub-critical electric fields. The effect of DC electric fields on the flame transfer function for acoustic modulation of the flow was also discussed.
FLOW TURBULENCE AND COMBUSTION
(2022)
Article
Physics, Fluids & Plasmas
Roman Zamchii, Jason S. Damazo, Eddie Kwon, Deanna A. Lacoste
Summary: This study investigates the effect of Wi-Fi signals on electrical discharges generated by high-voltage pulses of different durations. The results show that the energy and breakdown voltage of the discharges remain unchanged, while the amplitude of subsequent pulses slightly decreases. Under the current experimental conditions, the risk of electric breakdown ignition is very low.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2022)
Article
Physics, Fluids & Plasmas
N. Q. Minesi, V. P. Blanchard, E. Pannier, G. D. Stancu, C. O. Laux
Summary: This study investigates the effects of nanosecond repetitively pulsed (NRP) discharges in burnt gases, filling a gap in knowledge in this area. The researchers performed quantitative optical emission spectroscopy and measurements of electrical energy deposition to analyze the temperature and concentration variations during the discharge and characterize its properties. These measurements are important for future research, testing discharge kinetic models, and deriving a simplified model of plasma-assisted combustion.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Anupam Ghosh, Natalia M. Munoz-Munoz, Deanna A. Lacoste
Summary: The primary objective of this study is to measure the minimum ignition energy (MIE) of methane-air and hydrogen-air mixtures at low temperatures and atmospheric pressure. The results show that the MIE increases linearly with decreasing mixture temperature, and the rate of change is higher for hydrogen-air mixtures compared to methane-air mixtures. These findings are important for the design of cryogenic fuel storage systems.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Thermodynamics
Deanna A. Lacoste
Summary: Non-equilibrium plasma discharges can provide a favorable environment for combustion processes at low energy cost. This paper reviews recent progress in plasma-assisted combustion, with a focus on flame dynamics. Different plasma discharges and their effects on flame properties are presented, and the influence of these plasmas on the coupling between flames and acoustic waves is discussed. The shift towards favoring a chemical impact in plasma actuation is explained, and future research directions are proposed.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Samir B. Rojas Chavez, Karl P. Chatelain, Deanna A. Lacoste
Summary: This experimental study presents a proof-of-concept for measuring the induction zone length (⠂i) in H2-air detonations using laser-induced fluorescence (LIF) of nitric oxide (NO). The proof-of-concept is demonstrated through experiments in an optical detonation duct and numerical simulations. The results show a correlation between the NO-LIF signal evolution and ⠂i, with a theoretical accuracy of 2% and an experimental uncertainty of ±160-±μm. While a correlation between the induction length and cellular cycle could not be achieved due to imaging limitations, the experimental induction lengths correlate well with the simulations.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
B. Aravind, Vigneshwaran Sankar, Deanna A. Lacoste
Summary: The study focuses on the synthesis and analysis of low frequency flame oscillations in a Rijke tube combustor under external acoustic forcing. It is found that the system enters lock-in synchronization when the forcing frequency is in the range of 0.97 < ff / fn < 1.03 at a forcing amplitude of 10%, which results in quenching of the natural mode of the flame. Strong flame beating is observed on either side of this synchronization region. The flame transfer function (FTF) at the beating frequency is estimated and exhibits different behavior on either side of the synchronization region.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Amit Katoch, Thibault F. Guiberti, Daniel V. de Campos, Deanna A. Lacoste
Summary: In this study, a novel dual-fuel, dual-swirl burner is introduced, and its potential to mitigate thermoacoustic coupling for ammonia-hydrogen-air flames is explored. The researchers found that by adjusting the extent of mixing between ammonia and hydrogen before injection into the combustion chamber, the flame morphology and thermoacoustic behavior can be modified.
COMBUSTION AND FLAME
(2022)
Article
Energy & Fuels
Nader N. N. Shohdy, Mhedine Alicherif, Deanna A. A. Lacoste
Summary: This paper focuses on evaluating the effects of different levels of ammonia cracking on the overall burning velocity, lean blow-off limit, concentration of pollutants, and flame response to sound disturbances. Various ratios of cracked ammonia were experimentally investigated, and the results indicate that while ammonia cracking can improve the lean blow-off limit and burning velocity, it also leads to detrimental effects on pollutant emissions and flame stability, even at a low cracking percentage of 20%. Proposals for the reasons behind these results are provided based on flame dynamics analysis.
Article
Mechanics
J. Vargas, R. Mevel, M. Lino da Silva, D. A. Lacoste
Summary: In recent years, studies on detonation modeling have increasingly considered the thermal non-equilibrium assumption. Using two-temperature models, it has been shown that non-equilibrium has an impact on detonation dynamics. However, the use of state-to-state models, a leading non-equilibrium modeling tool, in detonation modeling has not been extensively explored. In this study, we present the implementation of a STS model of N-2 and O-2 in a Zel'dovich-von Neumann-Diring reactor for a mixture of H-2-air. Modifications are made to the conventional theory and models, specifically in the thermodynamics formulation, before deploying the aforementioned model. Additionally, a validation of an in-house code against CHEMKIN is conducted due to the incompatibility of most codes with STS models. The results suggest that the multi-temperature approach used in previous works may not be suitable for modeling the internal distribution function of O-2, and caution should be exercised when using it. Comparisons with experimental values confirm that the STS framework holds potential for more accurate detonation modeling.
Article
Physics, Fluids & Plasmas
Nicolas Q. Minesi, Pierre B. Mariotto, Erwan Pannier, Axel Vincent-Randonnier, Gabi Daniel Stancu, Christophe O. Laux
Summary: This study focuses on the formation of fully ionized plasmas in ambient air by nanosecond pulsed discharges, called thermal spark. The article first presents experimental characterization of the electron number density during the pulse, showing an increase up to 10^19 cm^-3 with sub-nanosecond resolution using three techniques based on optical emission spectroscopy. The study also develops a 0D kinetic mechanism to explain the observation, highlighting the importance of excited state kinetics in the thermal spark formation.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Mechanics
K. P. Chatelain, S. B. Rojas Chavez, J. Vargas, D. A. Lacoste
Summary: This study validates the new developments in the in-house spectroscopic code (KAT-LIF) for NO-LIF simulations under detonation conditions and evaluates the diagnostic capabilities of NO-LIF for characterizing H2-air detonations. The study involves updating KAT-LIF with a database of NO(A-X) transitions and implementing species-specific parameters for NO-LIF simulations. The validation of KAT-LIF is performed by comparing simulation results with pre-existing tools (LIFSim and LIFBASE) and experimental measurements, showing satisfactory agreement.
Article
Thermodynamics
Joao Vargas, Manuel Monge-Palacios, Deanna A. Lacoste
Summary: This study provides necessary data support for planetary probe missions by calculating the reaction rate constants involving molecular hydrogen.
JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER
(2023)
