Two-Dimensional Visualization of Premixed-Charge Flame Structure in an IC Engine - SP-715

Loye, A. O. zur; Bracco, F. V.

doi:10.4271/870454

Cited by 70 publications

(13 citation statements)

References 17 publications

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“…Generally, previous studies have assumed that the propagation of the spark-initiated oxidation is isotropic, i.e. spherical flame propagation [15,16,18,21,25,28,29,39,38,[30][31][32][33][34][35][36]. Only a few studies mentioned different flame-front geometries [14,15,30,39] and looked into implications arising from the assumption that the flame front surface had a spherical geometry.…”

Section: Visualisation Of Initial Flame Kernel Growth In Si Enginesmentioning

confidence: 99%

“…The effect of the turbulent flow field is crucial for the first and second stage of combustion. It has been shown that the smallest flame kernels are distorted shortly after ignition [25]. The laminar velocity is an intrinsic property of a combustible fuel, air and burned gas mixture.…”

Section: Flame Structure and Propagationmentioning

confidence: 99%

“…Applying the isotropic propagation assumption, the two-dimensional projected contours of spherical flames can be digitized and their various geometrical properties determined. Actual flame speeds and flame shapes were measured in a small number of studies, where the flame radii were calculated using the ''equivalent radius'' (EQR) method [39,25,15,38,16,32,33,40,41], which determines the radius from the measured area:…”

Section: Visualisation Of Initial Flame Kernel Growth In Si Enginesmentioning

confidence: 99%

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Assessment of elliptic flame front propagation characteristics of iso-octane, gasoline, M85 and E85 in an optical engine

Ihracska

Korakianitis

Ruiz

et al. 2014

Combustion and Flame

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a b s t r a c tPremixed fuel-air flame propagation is investigated in a single-cylinder, spark-ignited, four-stroke optical test engine using high-speed imaging. Circles and ellipses are fitted onto image projections of visible light emitted by the flames. The images are subsequently analysed to statistically evaluate: flame area; flame speed; centroid; perimeter; and various flame-shape descriptors. Results are presented for gasoline, isooctane, E85 and M85. The experiments were conducted at stoichiometric conditions for each fuel, at two engine speeds of 1200 rpm (rpm) and 1500 rpm, which are at 40% and 50% of rated engine speed. Furthermore, different fuel and speed sets were investigated under two compression ratios (CR: 5.00 and 8.14). Statistical tools were used to analyse the large number of data obtained, and it was found that flame speed distribution showed agreement with the normal distribution. Comparison of results assuming spherical and non-isotropic propagation of flames indicate non-isotropic flame propagation should be considered for the description of in-cylinder processes with higher accuracy. The high temporal resolution of the sequence of images allowed observation of the spark-ignition delay process. The results indicate that gasoline and isooctane have somewhat similar flame propagation behaviour. Additional differences between these fuels and E85 and M85 were also recorded and identified.

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Section: Visualisation Of Initial Flame Kernel Growth In Si Enginesmentioning

confidence: 99%

Section: Flame Structure and Propagationmentioning

confidence: 99%

Section: Visualisation Of Initial Flame Kernel Growth In Si Enginesmentioning

confidence: 99%

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Assessment of elliptic flame front propagation characteristics of iso-octane, gasoline, M85 and E85 in an optical engine

Ihracska

Korakianitis

Ruiz

et al. 2014

Combustion and Flame

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“…We begin by choosing a strain rate of 300 s _1 , a reasonable value for burning in an internal combustion engine [38]. To simulate propagation through a stratified mixture, a change in equivalence ratio from 1.0 to 0.6 is imposed on the reactants stream.…”

Section: Burning In a Stratified Mixturementioning

confidence: 99%

AFOSR Focused Research Initiative: Low-Emissions, High-Performance Gas Turbine Engines. Addenda A through E

Mongia¹,

Peters²,

Lucht³

et al. 1999

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“…Conventional SI combustion is generally understood as having four primary stages, as thoroughly documented and analyzed by many authors (Rassweiler & Withrow, 1935) (Rassweiler & Withrow, 1938) (Nakanishi, Hirano, Inoue, & Ohigashi, 1975) (Nakamura, et al, 1978) (zur Loye & Bracco, 1987 (Bozza, Gimelli, Merola, & Vaglieco, 2005) and subsequently consolidated by (Heywood, 1988) and others. It must be recognized that the body of knowledge necessary to draw our current understanding of these processes is much more vast than can be cited here, and the specific references presented are ones that the author found particularly helpful.…”

Section: Spark-ignited Combustion Backgroundmentioning

confidence: 99%

Analytical and Experimental Investigation of Temperature-Swing Insulation on Engine Performance

Andruskiewicz¹

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ResumenLos materiales aislantes han sido investigados a fondo por sus posibles mejoras en la eficiencia térmica de los motores de combustión interna alternativos. Estas mejoras se ven reflejadas tanto directamente en el trabajo indicado como indirectamente a través de la reducción del sistema de refrigeración del propio motor. Diferentes estudios, tanto experimentales como analíticos, han mostrado la reducción en la transferencia de calor a través de las paredes de la cámara de combustión mediante la utilización de estos materiales. Sin embargo, demostrar la conversión de la energía térmica adicional en trabajo indicado ha resultado más difícil. En ciertos estudios se pudieron obtener mejoras en el trabajo indicado durante la carrera de expansión, pero éstas fueron reducidas debido a un menor rendimiento volumétrico debido al calentamiento de la carga durante el proceso de admisión y un mayor trabajo en la carrera de compresión. Típicamente, las únicas mejoras en el trabajo al freno provendrían de la reducción de pérdidas por bombeo en los motores turboalimentados, o de la extracción de la energía adicional de los gases de escape a través de turbinas.El concepto de los materiales con oscilación de la temperatura durante el ciclo motor intenta aprovechar los beneficios del aislamiento durante los procesos de combustión y expansión, mitigando las perdidas por el incremento de la temperatura de las paredes durante la admisión y la compresión. La combinación de baja capacidad calorífica y baja conductividad térmica permitiría que la temperatura de la superficie de la cámara de combustión respondiera rápidamente a la temperatura del gas durante el proceso de combustión. Las temperaturas de la superficie son capaces de aumentar en respuesta al pico de flujo de calor, minimizando así la diferencia de temperatura entre el gas y la pared en la carrera de expansión cuando es posible la mayor conversión de energía térmica en trabajo mecánico. La combinación de baja capacidad calorífica y conductividad térmica es también esencial para permitir este aumento de temperatura durante la combustión y para permitir que la superficie se enfríe durante la expansión y el escape para no perjudicar así el rendimiento volumétrico del motor durante la carrera de admisión y minimizar el trabajo de compresión realizado en el siguiente ciclo.En esta tesis se han desarrollado modelos térmicos y termodinámicos para predecir los efectos de las propiedades de los materiales en las paredes y caracterizar los efectos de la transferencia de calor en diferentes partes del ciclo sobre el trabajo indicado, el rendimiento volumétrico, la energía en los gases de escape y las temperaturas del gas para un motor de combustión interna alternativo. También se ha evaluado el impacto del uso de estos materiales en el knock en motores de combustión de encendido provocado, ya que los estudios experimentales de esta tesis se realizaron en un motor de estas características.Durante la investigación se evaluaron materiales aislantes convencionales para comprender e...

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Two-Dimensional Visualization of Premixed-Charge Flame Structure in an IC Engine - SP-715

Cited by 70 publications

References 17 publications

Assessment of elliptic flame front propagation characteristics of iso-octane, gasoline, M85 and E85 in an optical engine

Assessment of elliptic flame front propagation characteristics of iso-octane, gasoline, M85 and E85 in an optical engine

AFOSR Focused Research Initiative: Low-Emissions, High-Performance Gas Turbine Engines. Addenda A through E

Analytical and Experimental Investigation of Temperature-Swing Insulation on Engine Performance

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