Investigation of the temporal evolution and spatial variation of in-cylinder engine fuel spray characteristics

Qin, Wenzhi; Hung, David L.S.; Xu, Min

doi:10.1016/j.enconman.2015.03.093

Cited by 20 publications

(6 citation statements)

References 34 publications

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“…Gasoline direct injection (GDI) has several advantages over port fuel injection, including improved fuel economy and transient response, more precise air-fuel ratio control, extended EGR tolerance limit, selective emissions advantages and enhanced potential for system optimization [1][2][3]. On the other hand, ethanol is a widely used alternative fuel to address the issue of sustainability.…”

Section: Introductionmentioning

confidence: 99%

Spray and evaporation characteristics of ethanol and gasoline direct injection in non-evaporating, transition and flash-boiling conditions

Huang

et al. 2016

Energy Conversion and Management

100

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16Ethanol direct injection plus gasoline port injection (EDI+GPI) represents a more efficient and flexible way to 17 utilize ethanol fuel in spark ignition engines. To exploit the potentials of EDI, the mixture formation 18 characteristics need to be investigated. In this study, the spray and evaporation characteristics of ethanol and 19 gasoline fuels injected from a multi-hole injector were investigated by high speed Shadowgraphy imaging 20 technique in a constant volume chamber. The experiments covered a wide range of fuel temperature from 275 K 21 (non-evaporating) to 400 K (flash-boiling) which corresponded to cold start and running conditions in an 22 engine. The spray transition process from normal-23 evaporating to flash-boiling was investigated in

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Section: Introductionmentioning

confidence: 99%

Spray and evaporation characteristics of ethanol and gasoline direct injection in non-evaporating, transition and flash-boiling conditions

Huang

et al. 2016

Energy Conversion and Management

100

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“…2:Nþ1 ) exceeds a value of 0.95, which is usually considered a very high level of similarity existing between two reconstructed flow fields [24,30]. The above process is depicted in the Fig.…”

Section: Proper Orthogonal Decomposition (Pod)mentioning

confidence: 99%

“…They partitioned the flow fields into three compositions (triple decomposition) based on an energy criterion. Then, Qin et al [24,30] expanded the application and decomposed the engine flow fields and spray images into four different parts (quadruple decomposition) to further describe the in-cylinder phenomena.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the effect of intake air swirl motion on time-resolved in-cylinder flow field using quadruple proper orthogonal decomposition

Zhuang

Hung

2016

Energy Conversion and Management

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a b s t r a c tThe control of intake air swirl motion is often used in spark-ignition direct-injection (SIDI) engine to improve its in-cylinder fuel-air mixing process especially under engine idle and low load conditions. In this experimental investigation, a novel technique combining the time-resolved particle image velocimetry (PIV) with quadruple proper orthogonal decomposition (POD) is implemented to analyze the time-resolved in-cylinder velocity measurements in an optically-accessible SIDI engine. The intake air swirl motion is introduced into the engine cylinder by a control valve installed in one of two air intake ports. Experimental results show that a strong linear correlation exists between the intake flow swirl ratio and vorticity flow field in the cylinder. This correlation ensures high data reliability of swirl motion control and provides a novel basis to directly compare the flow field measurements under different swirl ratio conditions. The quadruple proper orthogonal decomposition analysis is then applied to the velocity flow fields to separate the highly dynamic in-cylinder flow characteristics into four distinct categories: (1) dominant flow structure; (2) coherent structure; (3) turbulent structure; and (4) noise structure. The results show that the dominant flow structure varies strongly with swirl ratio, and its kinetic energy is also directly related to the swirl ratio. The coherent structure captures the large scale flow characteristics, but its kinetic energy is much lower and exhibits larger cycle-to-cycle variations. The turbulent structure contains similar level of kinetic energy at different swirl ratios but without much cycle-to-cycle variation. Finally, the noise structure contains very low kinetic energy which only alters the dynamic nature of the flow field slightly. In summary, the effect of swirl ratio on in-cylinder flow field is mostly captured by the dominant flow structure and partially captured by the coherent flow structure. The turbulent flow structure can characterize the high-order flow variation. The noise structure can be neglected due to the low energy captured.

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“…As conventional fossil fuels eventually run out, they can be replaced by the carbon neutral biofuels produced from the abundantly available biomaterials in some remote communities and contribute to reduced transportation cost and emissions 54 – 56 . Optimized performance of bio-oil sprays in novel power generation applications or upgraded existing systems such as alternative aviation fuels 57 , internal combustion engines 58 and gas turbines 59 – 61 are limited by our lack of understanding on their peculiar two-phase behaviour. Due to the complex physiochemical properties of pyrolysis oils, resulting in their resistance to break-up and atomization 62 – 64 , the current fundamental knowledge of their underlying two-phase physics need to be improved.…”

Section: Introductionmentioning

confidence: 99%

Fractal structures arising from interfacial instabilities in bio-oil atomization

Ghasemi

Yun

2021

Sci Rep

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The intriguing multi-scale fractal patterns ubiquitously observed in nature similarly emerge as fascinating structures in two-phase fluid flows of bio-oil breakup and atomization processes. High-resolution microscopy of the two-phase flows under 15 flow conditions (cases of different flow rates of the liquid and co-flowing air streams as well as different degrees of liquid preheating) reveal that the geometrical complexities evolve under the competing/combined action of the instability mechanisms such as Kelvin–Helmholtz, Rayleigh–Taylor and Rayleigh–Plateau leading into the transition from break-up to atomization. A thorough analysis of the higher order moments of statistics evaluated based on the probability density functions from 15,000 fractal dimension samples suggest that a single-value analysis is not sufficient to describe the complex reshaping mechanisms in two-phase flows. Consistently positive skewness of the statistics reveal the role of abrupt two-phase mechanisms such as liquid column rupture, ligament disintegration, liquid sheet bursting and droplet distortions in a hierarchical geometrical entanglement. Further, large kurtosis values at increased flow inertia are found associated with turbulence-induced intermittent geometrical reshaping. Interestingly, the proposed power-law correlation reveals that the global droplet size obtained from laser-diffraction measurements declines as the two-phase geometrical complexity increases.

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Investigation of the temporal evolution and spatial variation of in-cylinder engine fuel spray characteristics

Cited by 20 publications

References 34 publications

Spray and evaporation characteristics of ethanol and gasoline direct injection in non-evaporating, transition and flash-boiling conditions

Spray and evaporation characteristics of ethanol and gasoline direct injection in non-evaporating, transition and flash-boiling conditions

Characterization of the effect of intake air swirl motion on time-resolved in-cylinder flow field using quadruple proper orthogonal decomposition

Fractal structures arising from interfacial instabilities in bio-oil atomization

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