scholarly journals Numerical Simulation of Liquid Jet Atomization Including Turbulence Effects

2007 ◽  
Vol 129 (4) ◽  
pp. 920-928 ◽  
Author(s):  
Huu P. Trinh ◽  
C. P. Chen ◽  
M. S. Balasubramanyam
Keyword(s):  
Current Model ◽  
Droplet Breakup ◽  
Spray Angle ◽  
Liquid Jet ◽  
Primary Breakup ◽  
Turbulence Effects ◽  
Turbulence Effect ◽  
Blob Model ◽  
Secondary Breakup ◽  
Liquid Jet Atomization

This paper describes numerical implementation and validation of a newly developed hybrid model, T-blob/T-TAB, into an existing computational fluid dynamics (CFD) program for primary and secondary breakup simulation of liquid jet atomization. This model extends two widely used models, the Kelvin-Helmholtz (KH) instability of Reitz (the “blob” model) (1987, Atomization Spray Technol., 3, pp. 309–337) and the Taylor-Analogy-Breakup (TAB) secondary droplet breakup of O’Rourke and Amsden (1987, SAE Technical Paper No. 872089) to include liquid turbulence effects. In the primary breakup model, the level of the turbulence effect on the liquid breakup depends on the characteristic scales and flow conditions at the liquid nozzle exit. Transition to the secondary breakup was modeled based on energy balance, and an additional turbulence force acted on parent drops was modeled and integrated into the TAB governing equation. Several assessment studies are presented, and the results indicate that the existing KH and TAB models tend to underpredict the product drop size and spray angle, whereas the current model provides superior results when compared to the measured data.

PARAMETRIC EXPERIMENTS ON LIQUID JET ATOMIZATION SPRAY ANGLE

1991 ◽  
Vol 1 (1) ◽  
pp. 23-45 ◽  
Author(s):  
Francisco Ruiz ◽  
Norman Chigier
Keyword(s):  
Spray Angle ◽  
Liquid Jet ◽  
Atomization Spray ◽  
Liquid Jet Atomization

Modeling of Cavitation Induced Fuel Atomization and Breakup Processes

2017 ◽  
Author(s):  
Bolin Zhao ◽  
C. P. Chen
Keyword(s):  
Aerodynamic Force ◽  
Current Model ◽  
Flow Characteristics ◽  
Theoretical Development ◽  
Fuel Injector ◽  
Initial Flow ◽  
Cavitation Effect ◽  
Primary Breakup ◽  
Turbulence Effects ◽  
Large Pressure Gradient

Recent experimental and modeling studies have indicated that turbulence and cavitation behaviors within a realistic fuel injector have significant effects on the liquid atomization and spray processes. In addition to the breakup process induced by aerodynamic force at the liquid/gas interface, the effects of flow characteristics including turbulence and cavitation inside the injector nozzle on atomization have been shown to be important. The cavitation within the injector is complicated by the turbulent flow under large pressure gradient and geometry of the injector orifice. We have previously developed the “T-blob” and “T-TAB” model, for liquid fuel primary and secondary breakup predictions respectively, to account for liquid turbulence effects within the injector. The objective of this study is to further account for the cavitation effect in the atomization process of a cylindrical liquid jet. In the primary breakup model, the level of the turbulence effect on the liquid breakup depends on the characteristic scales and the initial flow conditions. These scales are further modified to include the cavitation effect. The drop size formed is estimated based on the energy distribution among wave, turbulence and cavitation modes. This paper describes theoretical development of the current model. Both non-evaporating and evaporating spray cases will be investigated to validate the newly developed cavitation-induced atomization model.

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.

LES of primary breakup of pulsed liquid jet in supersonic crossflow

2019 ◽  
Vol 154 ◽  
pp. 119-132 ◽  
Author(s):  
Y.H. Zhu ◽  
F. Xiao ◽  
Q.L. Li ◽  
R. Mo ◽  
C. Li ◽  
...  
Keyword(s):  
Liquid Jet ◽  
Primary Breakup

A Validated Two-Phase Flow Large Eddy Simulation Methodology

2013 ◽  
Author(s):  
Feng Xiao ◽  
Mehriar Dianat ◽  
James J. McGuirk
Keyword(s):  
Boundary Conditions ◽  
Level Set ◽  
Two Phase Flow ◽  
Local Level ◽  
Density Ratio ◽  
Cross Flow ◽  
Liquid Jet ◽  
Phase Flow ◽  
Two Phase ◽  
Primary Breakup

A robust two-phase flow LES methodology is described, validated and applied to simulate primary breakup of a liquid jet injected into an airstream in either co-flow or cross-flow configuration. A Coupled Level Set and Volume of Fluid method is implemented for accurate capture of interface dynamics. Based on the local Level Set value, fluid density and viscosity fields are treated discontinuously across the interface. In order to cope with high density ratio, an extrapolated liquid velocity field is created and used for discretisation in the vicinity of the interface. Simulations of liquid jets discharged into higher speed airstreams with non-turbulent boundary conditions reveals the presence of regular surface waves. In practical configurations, both air and liquid flows are, however, likely to be turbulent. To account for inflowing turbulent eddies on the liquid jet interface primary breakup requires a methodology for creating physically correlated unsteady LES boundary conditions, which match experimental data as far as possible. The Rescaling/Recycling Method is implemented here to generate realistic turbulent inflows. It is found that liquid rather than gaseous eddies determine the initial interface shape, and the downstream turbulent liquid jet disintegrates much more chaotically than the non-turbulent one. When appropriate turbulent inflows are specified, the liquid jet behaviour in both co-flow and cross-flow configurations is correctly predicted by the current LES methodology, demonstrating its robustness and accuracy in dealing with high liquid/gas density ratio two-phase systems.

Sign in / Sign up

Export Citation Format

Share Document