Soot temperature characterization of spray a flames by combined extinction and radiation methodology

Xuan, Tiemin; Desantes, J.M.; Pastor, Javier; García-Oliver, José M

doi:10.1016/j.combustflame.2019.03.023

Cited by 31 publications

(16 citation statements)

References 33 publications

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“…In addition to the above technical constraints, the fact that physicochemical formation pathways of soot are still not fully understood-even in zero-dimensional systems-may provide enough rationale for the wide interests in soot studies with simple flow configurations. In this regard, various laboratory-scale setups have been employed, including constant volume combustion chambers [23][24][25][26][27][28][29][30], shock tubes [31][32][33][34][35][36][37][38][39][40], well-stirred reactors [41][42][43][44][45], burner-stabilized flat premixed flames [46][47][48][49][50][51][52][53][54][55], coflow diffusion flames [56][57][58][59][60][61][62][63][64][65][66][67][68]…”

Section: Laboratory-scale Experimental Configurationsmentioning

confidence: 99%

“…Constant volume/pressure combustion chambers are typically used to study liquid fuel spray combustion [23][24][25][26][27][28][29][30], a close representation of the combustion process in CI engines. Unfortunately, soot formation during the burning of fuel sprays depends not only on soot chemistry but on many other physical processes such as spray penetration, droplet size distribution, and velocity field of the entrained air.…”

Section: Laboratory-scale Experimental Configurationsmentioning

confidence: 99%

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Soot formation in laminar counterflow flames

Wang

Chung

2019

Progress in Energy and Combustion Science

346

116

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Many practical soot-emitting combustion systems such as diesel and jet engines rely on diffusion flames for efficient and reliable operation. Efforts to mitigate soot emissions from these systems are dependent on fundamental understanding of the physicochemical pathways leading from fuel to soot in laminar diffusion flames. Existing diffusion flame−based soot studies focused primarily on overventilated coflow flame where the fuel gas (or vapor) issues from a cylindrical tube into a co-flowing oxidizer, and counterflow flame, where a reacting zone is established between two opposing streams of fuel and oxidizer. As a canonical diffusion flame configuration, laminar counterflow diffusion flames have been widely used as a highly controllable environment for soot research, enabling significant progress in the understanding of soot formation for several decades. In view of the possibility of fuel/oxidizer premixing in practical systems, counterflow partially premixed flames have also been studied. In the present work we intend to provide a comprehensive review of the researches on various aspects of soot formation utilizing counterflow flames. Major processes of soot formation (formation of gas phase soot precursors, soot inception and surface reactions, as well as particle-particle interactions) are examined first, with focus on the most recent (post-2010) research progress. Experimental techniques and associated challenges for the measurement of soot-related properties (some knowledge of which is helpful for full appreciation of the experimental data to be reviewed) are then introduced. This is followed by a detailed description of soot evolution in counterflow flames, which is complemented by a discussion on the similarity and differences of the sooting structures between counterflow and coflow diffusion flames. Parametric studies of the effects of fuel molecular structure, fuel additive, partial-premixing, pressure, temperature, stoichiometric mixture fraction, and residence time on soot formation in counterflow flames will then be addressed in detail. This review concludes with a summary of the knowledge and challenges gathered and demonstrated through decades of research, and an outlook on opportunities for future counterflow flame−based soot research towards a more complete understanding of soot formation and the development of novel techniques for soot mitigation in practical combustion devices.

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Section: Laboratory-scale Experimental Configurationsmentioning

confidence: 99%

Section: Laboratory-scale Experimental Configurationsmentioning

confidence: 99%

Soot formation in laminar counterflow flames

Wang

Chung

2019

Progress in Energy and Combustion Science

346

116

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“…A single-hole nozzle was used, which has been extensively studied in previous ECN studies [23,24]. The injector serial number is 210,675, with an actual nozzle diameter of 89.4 µm.…”

Section: Operating Conditionsmentioning

confidence: 99%

“…K is the soot dimensional extinction coefficient and L is the light beam path length through the soot cloud. Thus, the product KL represents the integral value of the soot extinction coefficient along the light path, which is related with the soot concentration [24]. Besides determining soot production through the KL factor, DBI is also suggested as an experimental standard to measure the liquid length (LL) of fuels by ECN [20].…”

Section: Diffused Back Illumination (Dbi) Extinction Imagingmentioning

confidence: 99%

Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions

et al. 2020

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The stringent emission regulations have motivated the development of cleaner fuels as diesel surrogates. However, their different physical-chemical properties make the study of their behavior in compression ignition engines essential. In this sense, optical techniques are a very effective tool for determining the spray evolution and combustion characteristics occurring in the combustion chamber. In this work, quantitative parameters describing the evolution of diesel-like sprays such as liquid length, spray penetration, ignition delay, lift-off length and flame penetration as well as the soot formation were tested in a constant high pressure and high temperature installation using schlieren, OH∗ chemiluminescence and diffused back-illumination extinction imaging techniques. Boundary conditions such as rail pressure, chamber density and temperature were defined using guidelines from the Engine Combustion Network (ECN). Two paraffinic fuels (dodecane and a renewable hydrotreated vegetable oil (HVO)) and two oxygenated fuels (methylal identified as OME1 and a blend of oxymethylene ethers, identified as OMEx) were tested and compared to a conventional diesel fuel used as reference. Results showed that paraffinic fuels and OMEx sprays have similar behavior in terms of global combustion metrics. In the case of OME1, a shorter liquid length, but longer ignition delay time and flame lift-off length were observed. However, in terms of soot formation, a big difference between paraffinic and oxygenated fuels could be appreciated. While paraffinic fuels did not show any significant decrease of soot formation when compared to diesel fuel, soot formed by OME1 and OMEx was below the detection threshold in all tested conditions.

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“…On the assumption that fuels have similar flame temperature, the differences of luminosity only correspond to formed soot. Additionally, in previous work, the relationship between flame temperature and soot concentration has been studied and it was determined that both parameters are not directly linked and the higher flame temperature is not the governing factor for higher soot production [37].…”

Section: Soot Formationmentioning

confidence: 99%

Experimental study of influence of Liquefied Petroleum Gas addition in Hydrotreated Vegetable Oil fuel on ignition delay, flame lift off length and soot emission under diesel-like conditions

Pastor

García

Micó

et al. 2020

Fuel

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The fundamental behaviour on ignition and combustion characteristics of blends of Hydrotreated Vegetable Oil and Liquid Petroleum Gas was investigated in a constant high pressure, high temperature combustion chamber, using a prototype lab-scale injection system adapted from a conventional common-rail system to conduct the injection events, ensuring that fuel was liquid at any point of the injection system and avoiding the formation of fuel vapour bubbles that could alter the injected fuel behaviour.The ignition delay, flame lift-off length and the soot formation were studied by means of highspeed imaging techniques, for different operating conditions. The aim of the work is to characterize the effect of Hydrotreated Vegetable Oil-Liquid Petroleum Gas blend ratios on the previously mentioned parameters.Experimental results show that the behaviour of the fuel blends follow the expected trends of conventional diesel type fuels when varying ambient temperature, density and injection pressure. Hydrotreated Vegetable Oil, being the highest reactivity fraction, controls auto ignition of the blend. However, Liquid Petroleum Gas acts as combustion inhibitor increasing both ignition delay and lift-off length as its ratio in the blend increases. As a consequence, the differences observed in terms of flame radiation suggest that increasing Liquid Petroleum Gas fraction reduces soot formation as it promotes a higher air/mixture.

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Soot temperature characterization of spray a flames by combined extinction and radiation methodology

Cited by 31 publications

References 33 publications

Soot formation in laminar counterflow flames

Soot formation in laminar counterflow flames

Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions

Experimental study of influence of Liquefied Petroleum Gas addition in Hydrotreated Vegetable Oil fuel on ignition delay, flame lift off length and soot emission under diesel-like conditions

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