Engine with Optically Accessible Cylinder Head: A Research Tool for Injection and Combustion Processes

Bermúdez, Vicente; García, José Manuel Sánchez; Juliá, Ernesto; Martínez, Simón Martínez

doi:10.4271/2003-01-1110

Cited by 47 publications

(41 citation statements)

References 22 publications

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“…This steady value agrees with time-resolved lift-off length derived from high-speed broad-band chemiluminescence images in [31]. As the flame evolves during the acceleration phase, LOL S remains at a quasi-steady level typical for reacting sprays in CPF vessels, where ambient gas dynamics are less influential in comparison to optical engines or rapid compression machines [5,18].…”

Section: Figure 3 Tosupporting

confidence: 71%

“…The usual approach for the research community to undertake spray mixing studies has been by decoupling it from the combustion process by using singular test rigs that reproduce engine thermodynamic conditions in an oxygen-free atmosphere [3][4][5][6]. Such non-reacting studies have been focused on the detailed description of quantitative spray parameters, such as vapor spray tip penetration, liquid length, or local equivalence ratio.…”

Section: Introductionmentioning

confidence: 99%

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An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

Desantes

Pastor

García-Oliver

et al. 2014

Combustion and Flame

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Schlieren imaging has helped deeply characterize the behavior of diesel spray when injected into an oxygen-free ambient. However, when considering the transient penetration of the reacting spray after autoignition, i.e. the Diesel flame, few studies have been found in literature. Differences among optical setups as well as among experimental conditions have not allowed clear conclusions to be drawn on this issue. Furthermore, soot radiation may have a strong effect on the image quality, which cannot be neglected.The present paper reports an investigation on the transient evolution of Diesel flame based upon schlieren imaging. Experimental conditions have spanned values of injection pressure, ambient temperature and density for typical Diesel engine conditions. An optimized optical setup has been used, which makes it possible to obtain results without soot interference. Based on observations for a long injection event (4 ms Energizing Time), the analysis has resorted to extensive comparison of inert and reacting sprays parameters, which have made it possible to define different phases after autoignition.Shortly after autoignition, axial and radial expansion of the spray have been observed in terms of axial penetration and radial cone angle. After that, during a stabilization phase, the reacting spray penetrates at a similar rate as the inert one. Later, the reacting spray undergoes an acceleration period, where it penetrates at a faster rate than the inert one. Finally, the flame enters a quasi-steady penetration phase, where the ratio of reacting and inert penetration stabilizes at a nearly constant value. The duration of the reacting spray penetration stages shows modifications when varying engine parameters such as air temperature, air density, injection pressure, and nozzle diameter. However, the proportionality between reacting and inert penetration has been observed to depend mainly on temperature, in agreement with observed reductions in entrainment when shifting from inert to reacting conditions.

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Section: Figure 3 Tosupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

Desantes

Pastor

García-Oliver

et al. 2014

Combustion and Flame

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“…Still, this particular test rig is capable of obtaining nearly quiescent, and steady thermodynamic conditions for very long periods of time. This design allows a better (and easier) control and replication of real engine-like test conditions [13] Engines with optical access are commonly used for similar purposes [16] but although they replicate more realistic conditions, they also introduce a lot of factors that could be undesired for the scope of certain studies, where a more controlled environment would be better suited.…”

Section: The Fuel Injection Systemmentioning

confidence: 99%

Needle lift profile influence on the vapor phase penetration for a prototype diesel direct acting piezoelectric injector

Payri

Viera

Plazas

2013

Fuel

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Elsevier Payri, R.; Gimeno, J.; Viera, JP.; Plazas Torres, AH. (2013). Needle lift profile influence on the vapor phase penetration for a prototype diesel direct acting piezoelectric injector. Fuel. 113:257-265. doi:10.1016Fuel. 113:257-265. doi:10. /j.fuel.2013 and not injection pressure. Ambient temperature alone seems not to have and important effect on vapor penetration. Finally, the effects of the needle lift profile in the instant injection rate and vapor penetration are presented, confirming the strong relation between these three parameters, and confirming also that the needle lift plays a determinant role in the spray development, especially at the early stages of the injection process. Both boot and ramp shaped injections proved the ability to strongly influence the vapor penetration rate. In comparison to the square shaped injection, the effect of the ramp shaped injection delays the vapor penetration right from the start of injection while the effect of the boot shaped injection takes considerably longer to become noticeable. From the results, the needle lift control feature has proven to be a very versatile tool for engine designers to control the injection process as desired, opening a new path with a plenty of room for improvement.

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“…An optically accessible single cylinder two-stroke engine with threeliter displacement, 15.6:1 compression ratio and low rotational speed of 500 rpm has been used for these experiments, which is described in detail in [22]. A cylindrical combustion chamber is designed with a diameter of 45mm.…”

Section: Test Rigmentioning

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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Engine with Optically Accessible Cylinder Head: A Research Tool for Injection and Combustion Processes

Cited by 47 publications

References 22 publications

An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

Needle lift profile influence on the vapor phase penetration for a prototype diesel direct acting piezoelectric injector

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

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