LES of primary breakup of pulsed liquid jet in supersonic crossflow

Zhu, Youhua; Feng, Xiao; Li, Q.L.; Mo, R.; Li, C.; Lin, Sen

doi:10.1016/j.actaastro.2018.10.043

Cited by 26 publications

(8 citation statements)

References 40 publications

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“…The standard k − ε model is based on the model transport equations for the turbulence kinetic energy ( k ) and its dissipation rate ( ε ) in the Reynolds-averaged Navier-Stokes (RANS) equations. In recent studies, researchers applied alternative, more accurate numerical methods to simulate the turbulent flow in engineering problems, such as the renormalization group (RNG) k − ε model (Shafaee and Mahmoudzadeh, 2017), direct numerical simulation (DNS) method (Prakash et al , 2019) and large eddy simulation (LES) method (Zhu et al , 2019; Yoo et al , 2017). However, the standard k − ε models were used in the present study because the use of a computational resource-saving numerical strategy is critical in engineering design processes.…”

Section: Numerical Modelling and Evaluation Criteriamentioning

confidence: 99%

Numerical investigation of the effect of the injection angle on the spray structures of an air-blast atomizer

Sheng

Xing

Liu

et al. 2020

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Purpose The purpose of this study is to investigate the effect of the injection angle α on the spray structures of an air-blast atomizer and help enhance the understanding of droplet-gas mixing process in such atomizers in the engineering domain. Design/methodology/approach The phenomena in the air-blast atomizer were numerically modelled using the computational fluid dynamics software Fluent 17.2. The Euler-Lagrange approach was applied to model the droplet tracking and droplet-gas interaction in studied cases. The standard k-ε model was used to simulate the turbulent flow. A model with a modified drag coefficient was used to consider the effects of the bending of the liquid column and its penetration in the primary breakup region. The Kelvin-Helmholtz, Rayleigh-Taylor model was applied to consider the secondary breakup of the droplets. Findings The basic spatial distribution and spray structures of the droplets corresponding to the angled liquid jet (α = 60°) were similar to those reported in liquid jets injected transversely into a gaseous crossflow studies. The injection angle α did not considerably influence the averaged Sauter to mean diameter (SMD) of the cross-sections. However, the spray structures pertaining to α = 30°, α = 60° and α = 90° were considerably different. In the case of the atomizer with multiple injections, a “collision region” was observed at α = 60° and characterized by a higher ci and larger averaged SMD in the central parts of the cross-sections. Originality/value The injection angle α is a key design parameter for air-blast atomizers. The findings of this study can help enhance the understanding of the droplet-gas mixing process in air-blast atomizers. Engineers who design air-blast atomizers and face new challenges in the process can refer to the presented findings to obtain the desired atomization performance. The code has been validated and can be used in the engineering design process of the gas-liquid jet atomizer.

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Section: Numerical Modelling and Evaluation Criteriamentioning

confidence: 99%

Numerical investigation of the effect of the injection angle on the spray structures of an air-blast atomizer

Sheng

Xing

Liu

et al. 2020

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“…Chang et al [23] proposed an approach for improving the liquid atomization performance by using a high-speed gas environment, and they verified that the droplet size was clearly affected by the gas velocity magnitude. Zhu et al [26] noted that a high-speed air flow was beneficial for improving pulsed fuel atomization performance, and numerical simulation results revealed that the penetration of a pulsed liquid jet and the width of a wake zone under high-speed air flow increased by 20% and 25%, respectively, resulting in an improvement of atomization and mixing performance. Deepu et al [27] experimentally investigated droplet behavior under the effect of ultrasonic vibration, and a theoretical model was established for investigating the atomization rate and droplet atomization lifetime.…”

Section: Introductionmentioning

confidence: 99%

Influence of atomizing core on droplet dynamic behavior and machining characteristics under synergistically enhanced twin-fluid spray

Chen

Gao

et al. 2020

Int J Adv Manuf Technol

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The droplet dynamic behavior of spraying during the manufacturing process affects tool life, cooling, and lubrication. A detailed understanding of droplet dynamic behavior is required to improve the surface quality while reducing the cutting fluid consumption. In this study, quantitative measurements for droplet diameter, number concentration, and axial velocity were carried out through a phase Doppler particle analyzer technique. The droplet characteristic spatial distributions of a standard twin-fluid nozzle (STN) and a novel twin-fluid nozzle (NTN) under different gas-to-liquid mass ratio (GLR) values were analyzed in detail. The results showed that the high-speed internal gas flow of an atomizing core has a significant effect on improving the synergistically enhanced atomization behavior, and more smaller droplets and an increased droplet momentum are easily obtained. Furthermore, a better spatial distribution of atomization characteristics can be achieved under a higher GLR of 4.3%. Furthermore, the effects of the novel atomizing core structural parameters on the droplet mean velocity spatial distribution, droplet turbulence, and root mean square velocity fluctuation were investigated. The results also showed that the improved NTN can effectively improve the spray atomization performance and droplet dynamic characteristics. In addition, comparative studies of the effect of the atomizing core structure on the machining performance were performed. Compared with the STN, the improved NTN achieves a significant reduction in cutting temperature, tool wear, and surface roughness of 17.25%, 33.96%, and 37.83%, respectively, owing to the better droplet dynamic characteristics and spatial distribution of spray atomization characteristics.

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“…Under the Eulerian-Lagrangian framework, the liquid trailing phenomenon of a liquid jet in a supersonic crossflow was captured using large eddy simulation (LES) in [33,34]. Using the CLSVOF method, the breakup process of a pulsed liquid jet in highspeed gas flow was studied in the works of [35]. This paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Elliptical Liquid Jet Primary Breakup In Supersonic Crossflow

Zhou

Feng

et al. 2020

International Journal of Aerospace Engineering

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The study of elliptical liquid jets in supersonic flow in a Mach 2.0 is performed numerically. The primary breakup process of the elliptical liquid jet is simulated for a Weber number 223, liquid/gas flux momentum 4.0. The aspect ratios of elliptical geometries are set to be 0.25, 0.5, 1, 2, and 5. The results show a remarkable difference in liquid jet disintegration morphology at different aspect ratios. Under supersonic crossflow conditions, the elliptical liquid jet shows more breakup characteristics than the round liquid jet. As the aspect ratio grows, the penetration depth decreases. The elliptical liquid jet with AR=0.25 has the largest penetration depth in all cases. Moreover, the round jet has a maximum spreading angle of 50.2°. The changing trends of the column breakup length both x direction and y direction are similar. The elliptical jet at a lower aspect ratio has a shorter breakup length due to the narrower windward area. The liquid jet has a pair of larger horseshoe vortex structure and a wider wake region at a higher aspect ratio. Two pairs of reversal vortex pairs with obvious characteristics can be observed in all the simulations.

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LES of primary breakup of pulsed liquid jet in supersonic crossflow

Cited by 26 publications

References 40 publications

Numerical investigation of the effect of the injection angle on the spray structures of an air-blast atomizer

Numerical investigation of the effect of the injection angle on the spray structures of an air-blast atomizer

Influence of atomizing core on droplet dynamic behavior and machining characteristics under synergistically enhanced twin-fluid spray

Simulation of Elliptical Liquid Jet Primary Breakup In Supersonic Crossflow

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