Modelling of pulsed RF corona discharges in high-pressure air

Auzas, F.; Makarov, M.; Naidis, G. V.

doi:10.1088/0022-3727/45/13/135202

Cited by 3 publications

(4 citation statements)

References 20 publications

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“…With the rapid development of pulsed power technology, a pulsed power supply with a fast rise time and a high overvoltage has been used to drive high-voltage discharges due to its high peak power [24][25][26][27][28][29][30][31]. Burlica and Locke obtained pulsed gliding discharges using a bipolar millisecond pulsed power supply; their experimental results showed that the energy yield for the destruction of an organic blue dye in a pulsed gliding discharge was 150 times higher than that in an ac gliding discharge [32].…”

Section: Introductionmentioning

confidence: 99%

Nanosecond-pulse gliding discharges between point-to-point electrodes in open air

Zhang

Shao

Yan

et al. 2014

Plasma Sources Sci. Technol.

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In this paper, gliding discharges with a point-to-point electrode geometry were produced by a repetitively pulsed power supply with a rise time of ∼100 ns and a full-width at half-maximum of ∼200 ns. The characteristics of such discharges were investigated by measuring their voltage-current waveforms and taking photographs of their discharge images. Experimental results showed that once the breakdown occurred, the nanosecond-pulse gliding discharges went into a stable stage at all air gaps, behaving in a mode of repetitive sparks. Under certain conditions, a non-stable stage would appear some time after the discharge went into the stable stage, in which the gliding discharges transitioned from repetitive sparks to diffuse discharges. Furthermore, several factors (gap spacing, pulse repetition frequency (PRF) and gas flow rate) influencing the discharge characteristics were investigated. It was observed that both the breakdown voltage and ignition voltage increased with the gap spacing, and a diffuse discharge was absent when the gap spacing was less than 6 mm. The breakdown voltage decreased with the increase in the PRF and its decrease ratio was larger in large gap spacing than in small gap spacing. Discharges would transit from repetitive sparks to diffuse discharges as the flow rate increased. Furthermore, a comparison of nanosecond-pulse and ac gliding discharges was conducted with respect to the power supply. The consumption and energy, the relationship between the power supply and the load, and the time interval between two pulses were three main factors which could lead to different characteristics between the nanosecond-pulse and ac gliding discharges.

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Section: Introductionmentioning

confidence: 99%

Nanosecond-pulse gliding discharges between point-to-point electrodes in open air

Zhang

Shao

Yan

et al. 2014

Plasma Sources Sci. Technol.

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“…The RF energy can be efficiently delivered to the discharge tips only if the system is optimally tuned, including treating the cylinder charge as a part of the electric circuit-a virtual capacitor. According to the publicized results, 51,[81][82][83][84][85][86][87][88][89][90][91][92][93] to date, the leading contenders for RF corona ignition prototyping includes the advanced corona ignition system (ACIS) by Federal Mogul and the Ecoflash corona ignition system by BorgWarner. One of the challenges of RF corona ignition is ensuring the inception of corona discharge while avoiding arc touchdown, especially in high-density conditions when a higher voltage is demanded.…”

Section: Rf Corona Ignitionmentioning

confidence: 99%

“…In addition to the difficulty to model the non-thermal plasma effect, for RF corona ignition, it is also of great challenge to predict the spatial distribution of the plasma branches, even though the energy and propagate distance of the plasma could be modelled. 91 Because of the promising potentials, advanced ignition technologies are deemed as a key enabler for high efficiency in future combustion engines. Significant advances in scientific understandings and engineering technologies are expected in order to tackle the associated challenges.…”

Section: Challenge and Outlookmentioning

confidence: 99%

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Future gasoline engine ignition: A review on advanced concepts

Zheng

2020

International Journal of Engine Research

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To meet the future requirements of fuel economy and exhaust emissions, high-efficiency gasoline engines tend to employ diluted combustion concepts along with intensified charge motion and stratified mixtures. Securing the ignition of such mixtures over the full engine operation range is challenging, because of the lowered mixture reactivity and increased discrepancy of stoichiometry. In recent years, increasing research efforts have been spending on innovations of ignition technologies to tackle the challenges. In this paper, the directions of ignition improvement are highlighted based on the fundamental understanding of the ignition mechanisms. The working principles of the primary types of advanced ignition systems are introduced; and relevant engine and combustion vessel test results are reviewed. The ignition systems are categorized as: (1) high-energy spark ignition, (2) pulsed nanosecond discharge ignition, (3) radio-frequency plasma ignition, (4) laser-induced plasma ignition, and (5) pre-chamber ignition. The advanced ignition systems are commented, regarding the ignition effectiveness and the implementation challenges, according to the literatures and the extensive empirical work at the authors’ laboratory.

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Fundamental investigation of unipolar and RF corona in atmospheric air

et al. 2021

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Unipolar (DC) and radio frequency (RF) corona at 3.3 MHz is studied at centimeter-sized gaps in a needle-plane geometry in atmospheric air at room temperature. Positive and negative corona using pure tungsten electrodes with varying tip angles revealed a lower onset voltage for the needle with the smaller included angle. The RF corona onset voltage and corresponding time delay were measured for a series of needles composed of pure tungsten or 2% lanthanated tungsten. The corona onset, established when the first instance of UV photon emission is detected via photomultiplier tube, occurred primarily during the negative half cycle of the applied RF voltage for pure tungsten needles. In contrast, with lanthanated tungsten needles, such preference was not observed. No distinguishable difference in onset voltage between pure tungsten and lanthanated tungsten was found, indicating that adding a small amount of lanthanum to tungsten has a negligible impact on the onset voltage at 3.3 MHz frequencies for electrodes at room temperature.

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Modelling of pulsed RF corona discharges in high-pressure air

Cited by 3 publications

References 20 publications

Nanosecond-pulse gliding discharges between point-to-point electrodes in open air

Nanosecond-pulse gliding discharges between point-to-point electrodes in open air

Future gasoline engine ignition: A review on advanced concepts

Fundamental investigation of unipolar and RF corona in atmospheric air

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