Experimental observation of end-gas autoignition and developing detonation in a confined space using gasoline fuel

Zhou, Lei; Li, Kuangdi; Zhao, Jianfu; Zhang, Xiaojun; Wei, Haiqiao

doi:10.1016/j.combustflame.2020.08.035

Cited by 9 publications

(3 citation statements)

References 10 publications

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“…However, there is an obvious delay for the case with d = 1.5 mm in terms of the flame propagation and detonation initiation process. The delay can be related to the experimental findings from Zhou et al [10] where the propensity of end-gas autoignition with developing detonation is found to be positively related to the initial main flame propagation and oxygen concentration in gasoline-air mixtures. For the simulations covered in this work, though, both cases eventually develop into detonation due to the highly reactive nature of ethylene and the use of pure oxygen as the oxidizer.…”

Section: Parametric Studies Of System Configuration and Stochasticity...mentioning

confidence: 53%

“…It was shown that the mean burning velocity in the main chamber could be significantly elevated as the pre-chamber jet entered the main chamber. Recently, Wei and co-workers [4,9,10] carried out a series of experiments in a confined combustion chamber to study: the flame acceleration after passing through a perforated plate, the subsequent propagation of turbulent jet flame and shock waves, resultant end-gas autoignition, and the stochasticity of detonation initiation. They observed various combustion modes, including normal combustion, oscillating combustion, and end-gas autoignition with and without DDT near the end wall of the combustion chamber by adjusting the jet flame speed, initial pressure, and fuel/air equivalence ratio.…”

Section: Introductionmentioning

confidence: 99%

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Parametric Studies of Deflagration-to-Detonation Transition in a Pre-Chamber/Main-Chamber System

Zhu

Tang

Lai

et al. 2022

ASME 2022 ICE Forward Conference

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Numerical simulations are performed to study the process of flame propagation through a small orifice and transition to detonation in a confined pre-chamber/main-chamber system. The numerical model solves the fully compressible Navier-Stokes equations by a high-order numerical algorithm on a dynamically adapting mesh, coupled with a single-step chemical-diffusive model for a stoichiometric ethylene-oxygen mixture. Four successive stages, namely laminar flame propagation, jet flame formation, flame distortion by shock waves, and transition to detonation, are observed. Parametric studies with varying nozzle diameters and initial temperatures are tested to investigate the effect of nozzle size and the stochasticity of deflagration-to-detonation transition (DDT). The results suggest that the case with a smaller nozzle size, d = 1.5 mm, requires a longer time for the flame to evolve and transition into a detonation. A small change in the initial temperature results in clear fluctuations of flame surface length in the turbulent flame regime. In addition, the case with the smaller orifice size is shown to be more sensitive to the initial temperature. Due to the stochastic nature of DDT, the time and location for detonation initiation vary in all cases. Nevertheless, the detonation mechanism remains the same and is independent of the small variations in the initial temperature or the orifice size.

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Section: Parametric Studies Of System Configuration and Stochasticity...mentioning

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Parametric Studies of Deflagration-to-Detonation Transition in a Pre-Chamber/Main-Chamber System

Zhu

Tang

Lai

et al. 2022

ASME 2022 ICE Forward Conference

View full text Add to dashboard Cite

show abstract

“…Engine knock is induced by the autoignition (AI) of a portion of the end-gases ahead of the propagating spark-ignited flame front. 7 It is a highly stochastic phenomenon dependent on fuel chemistry, local mixture state (influenced by turbulence intensity), combustion chamber design and engine operating conditions, as reported in the study from Wang et al 8 and from Zhou et al 9 Knock is a major constraint on the performance of SI engines [10][11][12] : being tightly correlated with pressure and temperature development in the unburnt mixture, knock often prevents the engine to operate at Maximum Brake Torque (MBT) timing, the latter being more advanced than the so-called Knock Limited Spark Advance (KLSA). The mitigation of knock risk is nowadays a key challenge for engine designers.…”

Section: Introductionmentioning

confidence: 99%

Impact of fuel surrogate formulation on the prediction of knock statistics in a single cylinder GDI engine

Fontanesi,

Shamsudheen,

Gonzalez

et al. 2023

International Journal of Engine Research

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The statistical tendency of an optically accessible single-cylinder direct-injection spark-ignition engine to undergo borderline/medium knocking combustion is investigated using 3D-CFD. Focus is made on the role of fuel surrogate formulation for the characterization of anti-knock quality and flame speed of the actual fuel. An in-house methodology is used to design surrogates able to emulate laminar flame speed and autoignition delay times of the injected fuel. Two different surrogates, characterized by increasing level of complexity, are compared. The most complex one (six components) improves the representation of the real fuel, highlighting the crucial role of accurate fuel kinetics to predict flame propagation and unburnt mixture reactivity. A devoted chemical mechanism including the oxidation pathways for all the species in the surrogate is also purposely developed for the current analysis. Knock is investigated using a proprietary statistical knock model (GruMo-UNIMORE Statistical Knock Model, GK-PDF), which can infer the probability of knocking events within a RANS formalism. Predicted statistical distributions are compared to measured counterparts. The proposed numerical/experimental comparison demonstrates the possibility to efficiently integrate complex-chemistry driven information in 3D-CFD combustion simulations without online solving chemical reactions: a combination of laminar flame speed correlations, ignition delay look-up tables, and a statistics-based knock model is adopted to estimate the percentage of knocking cycles in a GDI engine while limiting the computational cost of the simulations.

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The effect of ignition intensity and in-cylinder pressure on the knock intensity and detonation formation in internal combustion engines

Han

et al. 2022

Applied Thermal Engineering

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Experimental observation of end-gas autoignition and developing detonation in a confined space using gasoline fuel

Cited by 9 publications

References 10 publications

Parametric Studies of Deflagration-to-Detonation Transition in a Pre-Chamber/Main-Chamber System

Parametric Studies of Deflagration-to-Detonation Transition in a Pre-Chamber/Main-Chamber System

Impact of fuel surrogate formulation on the prediction of knock statistics in a single cylinder GDI engine

The effect of ignition intensity and in-cylinder pressure on the knock intensity and detonation formation in internal combustion engines

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