Plasma Temperature of Spark Discharge in a Lean-burn Spark-ignition Engine Using a Time Series of Spectra Measurements

Kawahara, Nobuyuki; Watanabe, Masanobu; Tomita, Eiji; Nagano, Yukihide; Kitagawa, Toshiaki

doi:10.4271/2019-01-2158

Cited by 4 publications

(6 citation statements)

References 10 publications

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“…In contrast, the minimum temperature is kept constant at 4000 K. Therefore, there is a non-negligible temperature variation inside the spark channel, which is about 15%-20% of the mean temperature. Several researchers experimentally investigated the temperature of spark discharge during the arc phase [36][37][38]. In a propanefueled SI engine, Kawahara et al [37] measured plasma vibrational temperature by using time series emission spectra from the electrically excited CN * violet band system.…”

Section: Spark Channel Evolutionmentioning

confidence: 99%

Numerical investigation of the spark discharge process in a crossflow

Kim¹,

Scarcelli²,

Karpatne³

et al. 2022

J. Phys. D: Appl. Phys.

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The present study numerically investigates the spark discharge process under crossflow conditions using a thermal equilibrium plasma solver that fully couples the electromagnetic physics and fluid dynamics in a computational framework. Numerical results are validated by the comparison with experimental data. The spark discharge experiment is performed in a constant volume vessel using an inductive coil ignition system for automotive applications, and the evolution of the spark channel is measured using high-speed imaging. The crossflow in the gap between the spark-plug electrodes is generated by a rotating fan with two different fan speeds, and the flow velocity across the gap is characterized by particle image velocimetry (PIV) measurement. A computational fluid dynamics (CFD) solver is employed to simulate the crossflow and provide the flow field variables (velocity, pressure, temperature) to the plasma solver. The crossflow velocity predicted in the flow simulation agrees well with the PIV data in that the non-uniform velocity profiles at monitoring points are reproduced by the CFD code. With the crossflow initialization in the plasma solver, the simulated spark discharge process from the breakdown to spark discharge matches the experimental data, including the voltage and circuit waveforms and the high-speed images of the spark channel evolution. The stretch of spark channel captured by plasma simulations agrees with the measured data. The plasma simulation reveals that the mean temperature of the spark channel is maintained at 5000 K during the discharge phase, and the temperature varies along the spark channel so that the highest value is obtained at the spark root on the center electrode. Overall, the results presented in this paper are meant to provide valuable information about the properties of the plasma generated by the spark discharge.

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Section: Spark Channel Evolutionmentioning

confidence: 99%

Numerical investigation of the spark discharge process in a crossflow

Kim¹,

Scarcelli²,

Karpatne³

et al. 2022

J. Phys. D: Appl. Phys.

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“…This work, for the first time, demonstrates reduction of GO using one of the most commonly occurring phenomenon of electric discharge at ambient conditions, popularly known as spark. The presence of higher order heat (5000−6800 K), 39 plasma, and electron bombardment 40 in spark simultaneously provide a compelling method to perform instantaneous reduction of GO in air medium at atmospheric temperature and pressure.…”

Section: ■ Introductionmentioning

confidence: 99%

Electric Spark Induced Instantaneous and Selective Reduction of Graphene Oxide on Textile for Wearable Electronics

Kedambaimoole

Kumar

Shirhatti

et al. 2020

ACS Appl. Mater. Interfaces

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Reduced graphene oxide (rGO) attracts great popularity as an alternative to pristine graphene because of the facile synthesis process of its precursor, graphene oxide (GO). Electrical conduction of GO is tunable, subject to the extent of reduction of oxygen functional groups in it. This work for the first time demonstrates rapid reduction of GO using spark at ambient conditions. A stream of spark generated by applying high electric potential across two electrodes, when passed through a film of GO deposited on a porous substrate, reduces it into rGO. Upon sparking, the electrical resistance of the GO film drops down by an order of six within a second, making the reduction process instantaneous. X-ray photoelectron spectroscopy and Raman spectra of spark-reduced graphene oxide (SrGO) films revealed a high C/O ratio with an increase in the domain of sp2-hybridized carbon. The electromechanical properties of SrGO were practically examined by testing it as a flex sensor by incorporating its films with commercially available gloves. It showed high sensitivity for bending and good repeatability while offering an easy route for textile integration, making an impactful statement about the potential of sparking as a cost-effective method to reduce GO on a large scale.

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“…For spark ignition of combustion devices, studies have ranged from investigating the electrical characteristics [3,4,5] to imaging of ignition kernels post-discharge [6,7]. Ample literature involves pronged electrodes with air-hydrocarbon mixtures, which had electrical input parameters and geometric shapes (e.g.…”

Section: Introductionmentioning

confidence: 99%

Examination of Annular-Electrode Spark Discharges in Flowing Oxygen – Experimental Nuances

Tinker

Pullen

Osborne

et al. 2019

AIAA Scitech 2019 Forum

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Microsecond sparks and the resulting plume of hot gas/plasma were examined against a parametric pressure-distance matrix. Schlieren imaging is used to capture the spatial and temporal location of spark discharge exhaust for two milliseconds. Low pressure and larger gap widths created the largest size and intensity signal for the spark-affected plumes. Experimental exit-plume velocities trend well with analytic predictions using a mean pressure between the chamber and atmospheric conditions. Due to the quadratic relation of the annulus area and gap width, larger gap width velocities are more accurately represented by analytic predictions using atmospheric pressure as the larger exit area restricts the flow less. The same pressure adjustment, when applied to breakdown voltages, improves data alignment with Paschen's Curve. I.

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Plasma Temperature of Spark Discharge in a Lean-burn Spark-ignition Engine Using a Time Series of Spectra Measurements

Cited by 4 publications

References 10 publications

Numerical investigation of the spark discharge process in a crossflow

Numerical investigation of the spark discharge process in a crossflow

Electric Spark Induced Instantaneous and Selective Reduction of Graphene Oxide on Textile for Wearable Electronics

Examination of Annular-Electrode Spark Discharges in Flowing Oxygen – Experimental Nuances

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