Experimental validation of an alternative method to predict high and low-temperature ignition delays under transient thermodynamic conditions for PRF mixtures using a Rapid Compression-Expansion Machine

Desantes, J.M.; Bermúdez, Vicente; López, J. Javier; Pintor, Dario Lopez

doi:10.1016/j.enconman.2016.09.089

Cited by 9 publications

(7 citation statements)

References 38 publications

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“…Numerical simulation of ignition delay times can help gain a deep insight into autoignition parameters, detailed kinetics, etc. In the present study, a zero‐dimensional model of a closed homogeneous reactor in CHEMKIN‐PRO 33 was used to predict the ignition delay phenomena of ammonia–methane/air mixtures in the shock tube experiments 34 . Moreover, the ignition delay times were also calculated for ammonia/methane fuels in a wider range of temperatures, pressures, and equivalence ratios to investigate combustion characteristics of such mixtures.…”

Section: Numerical Modelmentioning

confidence: 99%

Experimental and modeling study on ignition delay of ammonia/methane fuels

et al. 2020

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Summary Ammonia mixed with methane is a potential clean fuel for engine applications toward a low carbon economy. Studies are scarce on ignition phenomenon for ammonia/methane fuels in literature. In the present study, the ignition characteristics for ammonia–methane–air mixtures have been investigated by both experimental measurements and numerical simulations. Ignition processes of a 60%ammonia/40%methane (mol%) fuel blend were investigated with shock‐tube experiments. Measurements of the ignition delay times were performed behind reflected shock waves for such fuel/air mixtures with different equivalence ratios of 0.5, 1, and 2, at pressures around 2 and 5 atm within the temperature range of 1369 to 1804 K. Experimental results were then compared with numerical prediction results employing detailed kinetic mechanism, which showed satisfactory agreement within most of the range of the temperatures, equivalence ratios, and pressures investigated. Within the temperature range of 1300 to 1900 K, pressure range of 1 to 10 atm, equivalence ratio range of 0.5 to 2, and methane proportion range of 0% to 50% in fuel blends, the impacts of temperature, pressure, equivalence ratio, and methane additive were simulated on the ignition delay times of the fuel blends based upon the numerical model. It was found that the improvement of ammonia/methane ignition is significant with the increase of temperature, pressure, and methane additive while it is relatively not sensitive to equivalence ratio within the studied conditions. This suggests a promising potential of such fuel blends in real engine application. In addition to the calculations, reaction sensitivity analyses were also performed to have a deep insight into the observed differences between ammonia/methane/air ignition delay times with variation of conditions.

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Section: Numerical Modelmentioning

confidence: 99%

Experimental and modeling study on ignition delay of ammonia/methane fuels

et al. 2020

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“…On the same lines, even if the two nozzles in this study were assumed to produce sprays with similar break-up/ vaporization times or even shorter for the cylindrical nozzle, at the moment either spray reached vaporized ignitable mixtures the local equivalence ratio at the ignition location of the spray produced by the cylindrical nozzle k0 would be expected to be lower than that of the spray produced by nozzle k15, because of its significantly larger spread volume [31,54] at virtually similar injected mass [30]. As it is largely known, the reaction paths at low temperatures are dependent on radical species formed directly from the fuel, so richer mixtures oxidize faster [21,55]. Fig.…”

Section: Further Discussion On the Effect Of Nozzle Geometry Over Thementioning

confidence: 98%

The effect of nozzle geometry over ignition delay and flame lift-off of reacting direct-injection sprays for three different fuels

Payri

Viera

Gopalakrishnan

et al. 2017

Fuel

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h i g h l i g h t sSimultaneous Schlieren and OH * chemiluminescence visualizations are carried out with different techniques. The effect of nozzle geometry is analyzed for three different fuels along a wide test matrix in reactive conditions. Analysis of spray tip penetration, lift-off length and ignition delay. A total of 162 different test conditions are evaluated in the high temperature/high pressure test rig. The experimental database will be published and available for model validation. a b s t r a c tThe influence of internal nozzle flow characteristics over ignition delay, and flame lift-off of reacting direct-injection sprays is studied experimentally for three fuels using two different nozzle geometries. This is a continuation of previous work by the authors, where, evaporative and non-evaporative, isothermal spray developments were studied experimentally for the same nozzle geometries and fuels. Current study reports the ignition delay through Schlieren technique, and flame lift-off length through OH * chemiluminescence visualization. The nozzle geometries consist of a conical nozzle and a cylindrical nozzle with 8.6% larger outlet diameter when compared to the conical nozzle. The three fuels considered are n-heptane, n-dodecane and a three-component surrogate to better represent the physical and chemical properties of diesel fuel. Reacting spray is found to penetrate faster than non-reacting spray due to combustion induced acceleration after ignition. Higher oxygen concentration, and ambient temperature enhance the reactivity leading to higher spray tip penetration. Injection pressure does not affect the reactivity significantly and hence, influences spray penetration through momentum-similar to a non-reacting spray. Both ignition delay and lift-off length are found to be shortest and longest for n-dodecane and n-heptane, respectively, while the surrogate fuel falls in-between the two pure component fuels. Both ignition delay and lift-off length are found to decrease with increase in oxygen concentration, ambient temperature, and density. The cylindrical nozzle, in spite of shorter lift-off length is found to have longer ignition delay, when compared to the conical nozzle. This could be due to better atomization leading to larger spread angle and evaporative cooling from the cylindrical nozzle compared to a conical nozzle. The longer ignition delay also leads to leaner equivalence ratios at the time of ignition.

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“…In fact, the detailed mechanism for n-dodecane is avoided due to the high computational cost of generating the database by solving it. It should be mentioned that both chemical kinetic mechanisms have been validated in the working range versus experimental measurements in [22] and [23].…”

Section: Methodological Approachmentioning

confidence: 99%

“…Obviously, there is a certain deviation between predictions andexperiments, independently of using information from the database or from the correlations. However, the accuracy of the predictions will not be shown in this paper, since it has been discussed by Desantes et al in[21][22][23].…”

mentioning

confidence: 89%

“…Desantes et al [21,22] proposed an alternative integral method to predict both ignition delays, the one referred to cool flames and the other one referred to the high-temperature stage of the process. Such method is based on the accumulation and consumption of chain carriers to determine the time at which the critical concentration occurs.…”

Section: Introduction Justification and Objectivementioning

confidence: 99%

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Correlations for the ignition characteristics of six different fuels and their application to predict ignition delays under transient thermodynamic conditions

Desantes

Bermúdez

López

et al. 2017

Energy Conversion and Management

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Experimental validation of an alternative method to predict high and low-temperature ignition delays under transient thermodynamic conditions for PRF mixtures using a Rapid Compression-Expansion Machine

Abstract: Experimental validation of an alternative method to predict high and low-temperature ignition delays under transient thermodynamic conditions for PRF mixtures using a Rapid Compression

Cited by 9 publications

References 38 publications

Experimental and modeling study on ignition delay of ammonia/methane fuels

Experimental and modeling study on ignition delay of ammonia/methane fuels

The effect of nozzle geometry over ignition delay and flame lift-off of reacting direct-injection sprays for three different fuels

Correlations for the ignition characteristics of six different fuels and their application to predict ignition delays under transient thermodynamic conditions

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