An Assessment of fuel physical and chemical properties in the combustion of a Diesel spray

Nerva, Jean-Guillaume

doi:10.4995/thesis/10251/29767

Cited by 8 publications

(13 citation statements)

References 17 publications

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“…It shows that a one-to-one relationship between the lift-off length and the ignition delay time does not exist, as the exponent of 0.804 indicates that the lift-off length grows as ignition delay time increases, but not linearly, which is consistent with a previous study [28]. Moreover, the effect of the injection pressure was also consistent with a similar analysis presented previously in a Ph.D. thesis [48], where the exponent for the fuel exit velocity was 0.88, which is coherent with the value of 0.432 presented here. If the velocity can be related to the square root of the injection pressure…”

Section: Relationship Between Lift-off Length and Ignition Delay Timesupporting

confidence: 90%

“…The injection pressure, on the other hand, seems to have an almost negligible effect on the penetration of the liquid core [25,26,[41][42][43][44]48]. Therefore, and as mentioned in [20,25,49], the evaporation is a mixing-controlled process, meaning that the evaporation of the droplets takes place by the energy transferred from the surrounding air.…”

Section: Liquid Lengthmentioning

confidence: 97%

“…Lift-off length trends have usually been compared to those of auto-ignition delay [10,28,30,41,48]. As explained in Section 2.4, the second stage ignition or premixed combustion corresponds to the high rise of the heat release rate and the time that happens since the fuel has been injected to this point is known as the ignition delay time.…”

Section: Relationship Between Lift-off Length and Ignition Delay Timementioning

confidence: 99%

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An experimental study of the effects of fuel properties on diesel spray processes using blends of single-component fuels

Fajardo¹,

Martin²

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Resumen.Estosúltimos años, la tendencia en motores diesel ha sido la de emplear distintos tipos de combustibles para identificar su influencia y comportamiento sobre las emisiones y rendimiento. Dentro de la amplia variedad de combustibles empleados están los llamados combustibles de referencia (PRFs ingl. Primary Reference Fuels), los cuales representan el comportamiento del diesel y la gasolina en lo que respecta a propiedades de encendido, ya que se encuentran en ambos extremos de la escala del número de octano y también poseen números de cetano muy distintos. Una de las desventajas de utilizar gasolina pura o mezclas de diesel-gasolina en motores diesel es el tiempo que toma la mezcla en encender y quemar completamente el combustible. Esto generalmente requiere trabajar con cargas parciales o cargas premezcladas.Para poder aislar los efectos del combustibles sobre los procesos de un chorro y que sea capaz estudiar los parámetros característicos de tiempo de retraso de encendido, longitud de despegue de llama, penetración de líquido y vapor, entre otros, se han realizado distintos experimentos bajo variaciones paramétricas de condiciones de motor diesel. Los ensayos han sido realizados bajo condiciones inertes y reactivas en un motoróptico de dos tiempos y una instalación de alta presión y alta temperatura de flujo continuo a presión constante (CPF ingl. Constant-Pressure Flow ) empleando toberas mono-orificio, con aplicación de diversas técnicaś opticas. Para estudiar la influencia de las propiedades de los combustibles se utilizaron distintos mono-componentes, así como mezclas binarias y un sustituto de diesel conformado por seis componentes, el cual fuel comparado con diesel convencional. Adicionalmente, los resultados han sido contrastados con un modelo unidimensional para ayudar a explicar los valores y tendencias encontrados.Los resultados presentaron una fuerte dependencia de las propiedades de los combustibles en los ensayos realizados bajo condiciones inertes y reactivas. La diferencia entre las propiedades físicas del n-decano y n-hexadecano mostraron una reducción casi lineal sobre la longitud líquida estabilizada hasta aproximadamente un 60 % bajo ciertas condiciones. Adicionalmente, debido a la composición del combustible de sustitución, el n-hexadecano puro demostró tener características de evaporación prácticamente idénticas, probándose a sí mismo como un buen candidato para ser un sustituto mono-componente del diesel convencional. De una manera similar, las propiedades químicas de los PRFs n-heptano e iso-octano también probaron tener influencia sobre el desarrollo del chorro y radiación emitida. Se obtuvieron valores de tiempo de retraso con diferencias de hasta un orden de magnitud entre ambos extremos del rango de las mezclas, así como longitudes de despegue de llama hasta tres veces más largas. La radiación emitida por la incandescencia del hollín presentó las variaciones más altas, ya que algunas condiciones mostraron reducciones de hasta cuatroórdenes de magnitud dentro del rango de mezc...

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Section: Relationship Between Lift-off Length and Ignition Delay Timesupporting

confidence: 90%

Section: Liquid Lengthmentioning

confidence: 97%

Section: Relationship Between Lift-off Length and Ignition Delay Timementioning

confidence: 99%

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An experimental study of the effects of fuel properties on diesel spray processes using blends of single-component fuels

Fajardo¹,

Martin²

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“…On the other hand, spray development in the actual engine very often occurs under non-quiescent conditions. A lot of investigations on these spray and combustion parameters mentioned above have been done in different optical engines [12][13][14][15] with single-hole injectors. What's more, considering that multi-spray injectors are usually applied in real diesel engines, the influence of jet-to-jet interactions on combustion and soot formation have also been investigated by some researchers [16,17].…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study on Diesel Spray Injection into a Non-Quiescent Chamber

Pastor¹,

García-Oliver²,

García³

et al. 2017

SAE Int. J. Fuels Lubr.

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Visualization of single-hole nozzles into quiescent ambient has been used extensively in the literature to characterize spray mixing and combustion. However in-cylinder flow may have some meaningful impact on the spray evolution. In the present work, visualization of direct diesel injection spray under both non-reacting and reacting operating conditions was conducted in an optically accessible two-stroke engine equipped with a singlehole injector. Two different high-speed imaging techniques, Schlieren and UV-Light Absorption, were applied here to quantify vapor penetration for non-reacting spray. Meanwhile, Mie-scattering was used to measure the liquid length. As for reacting conditions, Schlieren and OH* chemiluminescence were simultaneously applied to obtain the spray tip penetration and flame lift-off length under the same TDC density and temperature. Additionally, PIV was used to characterize in-cylinder flow motion. Results were compared with those from the Engine Combustion Network database obtained under quiescent ambient conditions in a high pressure high temperature vessel. Because of the air flow induced by piston movement, in-cylinder conditions in the two-stroke engine during the spray injection are highly unsteady, which has a significant impact on the spray development and interference on the spray visualization. From the comparison with quiescent data from the Engine Combustion Network, air flow induced by piston movement was found to slow down tip penetration. Moreover, both ignition delay and lift-off length under unsteady flow conditions show less sensitivity with ambient temperature than that of quasi-steady conditions.

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“…are barely affected by the fuel evaporation [24]. Due to the low injection frequency used during 116 tests, the injected fuel initial temperature can be considered the same.…”

Section: 5) the Injected Mass Is So Low That Thermodynamic Conditimentioning

confidence: 99%

Application of optical diagnostics to the quantification of soot in n-alkane flames under diesel conditions

Pastor

García-Oliver

García

et al. 2016

Combustion and Flame

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Mico Reche, C. (2016). Application of optical diagnostics to the quantification of soot in n-alkane flames under diesel conditions. Combustion and Flame. 164:212-223. doi:10.1016/j.combustflame.2015.11.018. Nevertheless, it could still be a good option for low sooting conditions. On the other hand, an 36 attempt to calibrate LII signal by means of LEM measurements has been reported. This approach 37 should make it possible to obtain additional information on the soot spatial distribution. 38 However, inconsistencies have been identified which stem from the inherent limitations of LII 39 technique in highly sooting conditions. 40 Application of optical diagnostics to the quantification of soot in

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An Assessment of fuel physical and chemical properties in the combustion of a Diesel spray

Cited by 8 publications

References 17 publications

An experimental study of the effects of fuel properties on diesel spray processes using blends of single-component fuels

An experimental study of the effects of fuel properties on diesel spray processes using blends of single-component fuels

An Experimental Study on Diesel Spray Injection into a Non-Quiescent Chamber

Application of optical diagnostics to the quantification of soot in n-alkane flames under diesel conditions

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