Fuel Vaporization and Ignition Las in Diesel Combustion

Wakil, M. M. El; Myers, P. S.; Uyehara, O. A.

doi:10.4271/560063

Cited by 31 publications

(11 citation statements)

References 5 publications

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Section: Estimation Of Local Temperaturementioning

confidence: 99%

“…The local temperature can be estimated with the assumption of adiabatic mixing between the fuel and air [58,2,32,35,44]. The thermodynamic analysis with this adiabatic assumption was first introduced by El Wakil et al [58]. "Experimentally, adiabatic saturation as applied to the diesel spray would be realized by sealing a gas and a liquid that would not absorb the gas in an insulated container and allowing them to sit for a period of time until they reached thermodynamic equilibrium [58]."…”

Section: Estimation Of Local Temperaturementioning

confidence: 99%

“…"Experimentally, adiabatic saturation as applied to the diesel spray would be realized by sealing a gas and a liquid that would not absorb the gas in an insulated container and allowing them to sit for a period of time until they reached thermodynamic equilibrium [58]." Using energy conservation with an assumption that the saturation temperatures and evaporating rates of the fuel and TMPD are the same, the bulk mean temperature (T mix ) in the region where all fuel has evaporated was calculated as follows [58];…”

Section: Estimation Of Local Temperaturementioning

confidence: 99%

“…where T amb is the temperature of the gas entrained into the spray Also, the bulk mean temperature (T mix ) in the region where the final equilibrium mixture contains air, fuel vapor and liquid fuel in equilibrium with its vapor can be calculated as follows [58]; Thermodynamic and physical properties of the doped fuel were determined from references 60 and 61 at an assumed mixture of 90% dodecane and 10% naphthalene since data for TMPD was not available. The mixture data was determined using Dalton's and Raoult's laws applied to the vapor and liquid phase respectively.…”

Section: Estimation Of Local Temperaturementioning

confidence: 99%

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Quantitative 2-D Fuel Vapor Concentration Measurements in an Evaporating Diesel Spray using the Exciplex Fluorescence Method

Kim

Ghandhi

2001

SAE Technical Paper Series

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QUANTITATIVE 2-D FUEL VAPOR CONCENTRATION MEASUREMENTS IN AN EVAPORATING DIESEL SPRAY USING THE EXCIPLEX FLUORESCENCE METHOD Tongwoo KimUnder the Supervision of Professor Jaal B. Ghandhi at the University of Wisconsin -MadisonTo experimentally investigate evaporating sprays under conditions experienced in high speed direct-injection (HSDI) diesel engines, the exciplex (excited state complex)laser-induced fluorescence technique and high-speed natural luminosity cinematography were applied for non-reacting and reacting diesel sprays respectively, in a combustiontype constant-volume spray chamber. The combustion-type spray chamber was developed and provides conditions representative of a diesel engine at the start of fuel injection with good repeatability.A detailed set of calibration experiments were performed in order to quantify the TMPD (tetramethyl-p-phenylene-diamine) fluorescence signal. The effects of pressure and collision partner were found to be negligible. The effect of temperature was found to increase the fluorescent yield up to 600 K, then decrease it for further increases intemperature. An adiabatic mixing model for the estimation of the temperature reduction due to vaporization allowed correction of the temperature effects, and laser beam absorption and laser spatial non-uniformity were also corrected in the final calibration procedure.ii To assess the accuracy of the calibration procedure, the fuel vapor concentration was integrated and found to agree well with the mass of fuel injected (< 10%) after the end of injection when all the liquid fuel was vaporized. Estimation of the uncertainty of the measurements was 21%.Using a density of 15 kg/m 3 the effects of three ambient gas temperatures (800, 1000 and 1200 K), three peak injection pressures (60, 90 and 150 MPa) and three nozzle hole sizes (0.14, 0.158 and 0.2 mm) were investigated based on the calibrated exciplex concentration measurements. Limited experiments were performed at 7.5 kg/m 3 .The data indicate that early in the injection event liquid and vapor coexist at the spray leading edge, however the liquid length reaches a terminal value and the vapor phase continues to penetrate. Lower ambient gas density were shown to provide faster vapor penetration and longer liquid lengths. Higher ambient gas temperatures were shown to produce a wider radial vapor extent with higher equivalence ratios and higher gradients at the edge of the jet. Distributions of the vapor concentration for higher injection pressures showed faster fuel vaporization rates and larger spray head volumes.Larger nozzle hole sizes were shown to have faster vapor-phase penetration rates and longer liquid lengths. The effects of the aforementioned parameters on the sprayspreading angle were shown to be transient in nature although as injection progressed the steady values were achieved.Natural luminosity images from reacting diesel sprays were acquired and compared with the exciplex image data to understand the equivalence ratio distribution during the ignition and in...

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Section: Estimation Of Local Temperaturementioning

confidence: 99%

Section: Estimation Of Local Temperaturementioning

confidence: 99%

Section: Estimation Of Local Temperaturementioning

confidence: 99%

Section: Estimation Of Local Temperaturementioning

confidence: 99%

See 2 more Smart Citations

Quantitative 2-D Fuel Vapor Concentration Measurements in an Evaporating Diesel Spray using the Exciplex Fluorescence Method

Kim

Ghandhi

2001

SAE Technical Paper Series

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“…A sketch of the installation used in this work is depicted in figure 3.18. The technique, previously developed for fluorescence microscopy [85], is based on an incident laser-sheet which is spatially modulated along the perpendicular direction of the sheet. Three images are recorded successively while the phase is shifted by a third of a period between acquisition of each image of the set.…”

Section: Structured Laser Illumination Planar Imaging (Slipi)mentioning

confidence: 99%

Analysis of Mixing Processes in Liquid and Vaporized Diesel Sprays Through Lif and Rayleigh Scattering Measurements

Manin¹,

Luc²

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ResumenDesde su introducción, los motores de combustión interna alternativos han sido desarrollados con el fin de reducir el consumo y mejorar el rendimiento y facilidad de conducción. Con el tiempo, la contaminación se ha convertido en un factor crítico para los gobiernos y como consecuencia se han introducido regulaciones para reducir las emisiones contaminantes de los motores.Con el constante progreso tecnológico requerido por las normas contra la contaminación, la inyección directa se ha vuelto indispensable en cuanto a los motores Diesel. La introducción de combustible en la cámara de combustión permite un alto nivel de control sobre la liberación de energía del proceso de combustión. Con las novedosas estrategias de combustión empleadas, el proceso de inyección se ha convertido en el tema principal y el chorro es el factor principal.El trabajo realizado a lo largo de este estudio para analizar el proceso de mezcla aire-combustible se basa en el desarrollo de técnicas láser de diagnós-tico. Inicialmente, la inyección de Diesel se ha estudiado en una atmósfera isoterma para evitar la evaporación del combustible (n-dodecano) a través del uso de una iluminación estructurada para medir la distribución de la mezcla mediante el control de la dispersión de Mie. La aplicación de la dispersión de Rayleigh en la parte evaporada del chorro inyectado en una cámara a alta temperatura ha permitido la obtención de la distribución de combustible en una situación equivalente a la existente en un motor real.El análisis y comparación de los distintos parámetros del chorro inyectado en condiciones de baja o alta temperatura da la posibilidad de entender mejor lo que es el proceso de mezcla en los motores Diesel. Por otra parte, según el estado del fluido inyectado, líquido o gaseoso, las condiciones experimentales tendrán diferentes efectos y la mezcla aire-combustible también tendrá un comportamiento distinto. ResumDes de la seua introducció, els motors de combustió interna alternatius han sigut desenrotllats amb el primer objectiu de reduir el consum i millorar el rendiment i facilitat de conducció. Amb el temps, la contaminació s'ha convertit en un factor crític per als governs i com a conseqüència s'han introduït regulacions per a reduir les emissions contaminants dels motors.Amb el constant progrés tecnològic requerit per les normes contra la contaminació, la injecció directa s'ha tornat indispensable quant als motors Dièsel. La introducció de combustible en la cambra de combustió permet un alt nivell de control sobre l'alliberament d'energia del procés de combustió. Amb les noves estratègies de combustió empleades, el procés d'injecció s'ha convertit en el tema principal i el doll és el factor principal.El treball realitzat al llarg d'este estudi per a analitzar el procés de mescla aire-combustible es basa en el desenrotllament de tècniques làser de diagnòs-tic. Inicialment, la injecció de Dièsel s'ha estudiat en una atmosfera isoterma per a evitar l'evaporació del combustible (n-dodecà) a través de l'ús d'una il·luminac...

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Quantitative vapor phase exciplex fluorescence measurements at high ambient temperature and pressure

Kim

Ghandhi

2003

KSME International Journal

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Fuel Vaporization and Ignition Las in Diesel Combustion

Cited by 31 publications

References 5 publications

Quantitative 2-D Fuel Vapor Concentration Measurements in an Evaporating Diesel Spray using the Exciplex Fluorescence Method

Quantitative 2-D Fuel Vapor Concentration Measurements in an Evaporating Diesel Spray using the Exciplex Fluorescence Method

Analysis of Mixing Processes in Liquid and Vaporized Diesel Sprays Through Lif and Rayleigh Scattering Measurements

Quantitative vapor phase exciplex fluorescence measurements at high ambient temperature and pressure

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