Surface Properties During Primary Breakup of Turbulent Liquid Jets in Still Air

AIAA Journal ◽  
2003 ◽  
Vol 41 (8) ◽  
pp. 1514-1524 ◽  
Author(s):  
K. A. Sallam ◽  
G. M. Faeth
Keyword(s):  
Surface Properties ◽  
Liquid Jets ◽  
Primary Breakup

PRIMARY BREAKUP OF ROUND AERATED-LIQUID JETS IN SUPERSONIC CROSSFLOWS

2006 ◽  
Vol 16 (6) ◽  
pp. 657-672 ◽  
Author(s):  
K. A. Sallam ◽  
C. Aalburg ◽  
G. M. Faeth ◽  
K.-C. Lin ◽  
C. D. Carter ◽  
...  
Keyword(s):  
Liquid Jets ◽  
Primary Breakup

Simulation of Laminar Liquid Jets in Gaseous Crossflow Before the Onset of Primary Breakup

2011 ◽  
Author(s):  
C.-L. Ng ◽  
K. A. Sallam
Keyword(s):  
Experimental Data ◽  
Fuel Injection ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Jet Breakup ◽  
Primary Breakup ◽  
Density Ratios ◽  
First Time ◽  
Two Sides ◽  
Reduced Pressures

The deformation of laminar liquid jets in gaseous crossflow before the onset of primary breakup is studied motivated by its application to fuel injection in jet afterburners and agricultural sprays, among others. Three crossflow Weber numbers that represent three different liquid jet breakup regimes; column, bag, and shear breakup regimes, were studied at large liquid/gas density ratios and small Ohnesorge numbers. In each case the liquid jet was simulated from the jet exit and ended before the location where the experimental data indicated the onset of breakup. The results show that in column and bag breakup, the reduced pressures along the sides of the jet cause the liquid to move to the sides of the jet and enhance the jet deformation. In shear breakup, the flattened upwind surface pushes the liquid towards the two sides of the jet and causing the gaseous crossflow to separate near the edges of the liquid jet thus preventing further deformation before the onset of breakup. It was also found out that in shear breakup regime, the liquid phase velocity inside the liquid jet was large enough to cause onset of ligament formation along the jet side, which was not the case in the column and bag breakup regimes. In bag breakup, downwind surface waves were observed to grow along the sides of the liquid jet triggered a complimentary experimental study that confirmed the existence of those waves for the first time.

scholarly journals Effects of Nanoparticle Additives on Spray Characteristics of Liquid Jets in Gaseous Crossflow

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1574
Author(s):  
Weidong Shi ◽  
Fengyu Li ◽  
Qizhao Lin ◽  
Guofeng Fang ◽  
Liang Chen ◽  
...  
Keyword(s):  
High Performance ◽  
Liquid Jets ◽  
Pure Liquid ◽  
Fracture Position ◽  
Transition Mechanism ◽  
Basic Fluid ◽  
Jet Trajectory ◽  
Primary Breakup ◽  
Transverse Injection ◽  
Nanoparticle Additives

Nanofluids are attracting attention as future energy carriers owing to their high performance for improving combustion and heat transfer. In this study, the macroscopic characteristics of nanofluid jets in a subsonic gaseous crossflow were investigated by focusing on the influence of nanoparticle additives on the breakup process. Based on a distribution map of the image grayscale standard deviation, we propose an improved method to process transverse injection shadowgraphs. A simplified model of the transition mechanism from column breakup to surface breakup at a small Weber number was established. The effects of nanoparticles on the jet trajectory and column fracture position were analyzed according to the deviations from the pure liquid. To interpret the effects of the nanoparticles, a new nondimensional parameter was introduced into the empirical correlation of the column fracture position. The results indicated that at low concentrations of nanoparticles, the surface tension of the nanofluids increased slightly, while the viscosity increased significantly (by up to 23%). These changes in the physical properties had little effect on the breakup regimes or jet trajectory. Moreover, the nanoparticles promoted cavitation inside the liquid column, resulting in an additional primary breakup mode for the nanofluids. Consequently, the length of the column fracture was reduced by up to 20% compared with that of the basic fluid.

Breakup of Liquid Jets Emerging From Elliptic Orifices

2011 ◽  
Author(s):  
Ghobad Amini ◽  
Ali Dolatabadi
Keyword(s):  
Passive Control ◽  
Fuel Efficiency ◽  
Ambient Air ◽  
Spreading Rate ◽  
Liquid Jets ◽  
Combustion Instabilities ◽  
Mass Entrainment ◽  
Circular Jets ◽  
Primary Breakup ◽  
Nozzle Geometries

Passive control can result in increasing fuel efficiency and reducing combustion instabilities of gas turbine spray combustors. Through the use of geometric modifications of the conventional circular nozzles, this method potentially enhances mixing which is responsible for entraining the bulk air necessary for combustion. Several studies show that elliptic jets have higher mass entrainment and spreading rate compared to the equivalent circular jets [1]. The majority of these works have been limited to gaseous jets. The present study focuses on a liquid spray discharging into still ambient air from a single-hole injector with elliptic cross-section. The primary breakup is investigated using a theoretical approach. Characteristics of elliptic orifice jet are compared with circular orifice jet under different breakup regimes and various nozzle geometries.

scholarly journals Simulation of Elliptical Liquid Jet Primary Breakup In Supersonic Crossflow

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yao-zhi Zhou ◽  
Feng Xiao ◽  
Qing-lian Li ◽  
Chen-yang Li
Keyword(s):  
Aspect Ratio ◽  
Penetration Depth ◽  
Horseshoe Vortex ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Breakup Length ◽  
Aspect Ratios ◽  
Primary Breakup ◽  
Elliptical Jet ◽  
Maximum Spreading

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.

On the Breakup Process of Round Liquid Jets in Gaseous Crossflows at Low Weber Number

2013 ◽  
Author(s):  
Shao-lin Wang ◽  
Yong Huang ◽  
Fang Wang ◽  
Zhi-lin Liu ◽  
Lei Liu
Keyword(s):  
Weber Number ◽  
High Speed ◽  
Droplet Diameter ◽  
Liquid Jets ◽  
Breakup Process ◽  
Ohnesorge Number ◽  
Propulsion Systems ◽  
Momentum Ratio ◽  
Breakup Length ◽  
Primary Breakup

Liquid jets in cross air flows are widely used and play an important role in propulsion systems, such as ramjet combustors. In this paper, experiments were carried out to investigate the properties of the primary breakup of liquid jets in subsonic transverse airflows at low Weber number. The test ranges included crossflow Weber numbers of 0.5–6.7, liquid-to-gas momentum ratios of 3–120, and Ohnesorge number of 0.0086. Four different injectors with diameter 0.4mm, 0.5mm, 0.6mm and 1mm have been used. A high speed camera was used to observe the jet column breakup process. Results show that the surface wavelength decreases not only with the increase of the gas Weber number but also with the increase of the momentum ratio. The breakup length decreases with the increase of the gas Weber number, in addition to its increase with the increase of the momentum ratio. The droplet diameter decreases with the increase of both the gas Weber number and momentum ratio, although the gas Weber number will dominate the breakup process. The surface wavelength, breakup length, and droplet diameter were also analyzed with to obtain semi-theoretical correlations.

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