Multi-plume sprays interacting with subsonic compressible gas jets

Ghasemi, Abbas; Pereira, Aaron; Li, Xianguo; Ren, Yang

doi:10.1016/j.apenergy.2017.01.008

Cited by 5 publications

(2 citation statements)

References 30 publications

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“…These simultaneous measurements assisted the efforts to model the air fuel mixing process. Ghasemi et al [13] investigated the interactions between multi-plume spray and subsonic gas jets. They demonstrated that the gas jet accelerated the spray atomization and spray altered velocity and pressure fields of the gas flow.…”

Section: Introductionmentioning

confidence: 99%

Influence of Early and Late Fuel Injection on Air Flow Structure and Kinetic Energy in an Optical SIDI Engine

Chen

Zhuang

Reuss

et al. 2018

SAE Technical Paper Series

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he turbulent in-cylinder air flow and the unsteady high-pressure fuel injection lead to a highly transient air fuel mixing process in spark-ignition directinjection (SIDI) engines, which is the leading cause for combustion cycle-to-cycle variation (CCV) and requires further investigation. In this study, crank-angle resolution particle image velocimetry (PIV) was employed to simultaneously measure the air flow and fuel spray structure at 1300 rpm in an optically accessible single-cylinder SIDI engine. The measurement was conducted at the center tumble plane of the four-valve pent-roof engine, bisecting the spark plug and fuel injector. 84 consecutive cycles were recorded for three engine conditions, i.e. (1) none-fueled motored condition, (2) homogeneous-charge mode with start of injection (SOI) during intake (50 crank-angle degree (CAD) after top dead center exhaust, aTDCexh), and (3) stratified-charge mode with SOI during mid compression (270 aTDCexh). The air flow structure (quantified by the objective metric-relevance index) and kinetic energy were examined to study the effect of the fuel spray on the air flow. The air flow was nearly identical for three conditions before the fuel injection. During fuel injection, the entrainment of air into the spray was observed near the spray but the flow structure further away from the spray was not significantly affected for both homogeneous and stratified charge modes. Right after the fuel was atomized, the spray increased the kinetic energy of air f low by 48 ± 25% and 45 ± 40% (average ± standard variation, with CCV included in standard deviation) for spray at intake and compression stroke, respectively. Spray changed the flow structure and kinetic energy immediately after injection for both conditions. The changes caused by injection during intake did not affect the flow and CCV at spark timing. For injection during mid compression, both the flow-structure and kinetic-energy CCV were apparently affected at spark timing. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE International.

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Section: Introductionmentioning

confidence: 99%

Influence of Early and Late Fuel Injection on Air Flow Structure and Kinetic Energy in an Optical SIDI Engine

Chen

Zhuang

Reuss

et al. 2018

SAE Technical Paper Series

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“…One of the most complex yet fascinating classes of fluid dynamics are the two-phase flows in which a competing effect from gravity 36 and inertial forces against resistances arising from the differences in physical properties such as viscosity, surface tension and density produces a broad range of complex interfacial geometries. Such complexities arise from the onset of instability mechanisms such as Kelvin–Helmholtz (KH), Rayleigh–Taylor (RT) and Rayleigh–Plateau (RP) where initial linear growth of the perturbations transition into non-linear state and generate geometrically sophisticated structures in the form of liquid sheets, ligaments and distorted droplets of various length scales 37 , 38 . The KH instability sets in whenever a large velocity difference across an interface distorts the boundary between two layers of fluid and results in vortex roll-up 25 .…”

Section: Introductionmentioning

confidence: 99%

Fractal structures arising from interfacial instabilities in bio-oil atomization

Ghasemi

Yun

2021

Sci Rep

Self Cite

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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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Large-Eddy Simulation of two secondary air supply strategies in kraft recovery boilers

Laitinen

Laurila²,

Keskinen³

et al. 2022

Applied Thermal Engineering

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Multi-plume sprays interacting with subsonic compressible gas jets

Cited by 5 publications

References 30 publications

Influence of Early and Late Fuel Injection on Air Flow Structure and Kinetic Energy in an Optical SIDI Engine

Influence of Early and Late Fuel Injection on Air Flow Structure and Kinetic Energy in an Optical SIDI Engine

Fractal structures arising from interfacial instabilities in bio-oil atomization

Large-Eddy Simulation of two secondary air supply strategies in kraft recovery boilers

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