Analysis of Liquid Jet Breakup in One- and Two-Phase Flows

2012 ◽  
Vol 35 (9) ◽  
pp. 1685-1691 ◽  
Author(s):  
M. Ochowiak ◽  
L. Broniarz-Press ◽  
S. Rozanska
Keyword(s):  
Liquid Jet ◽  
Two Phase Flows ◽  
Two Phase ◽  
Jet Breakup

scholarly journals CFD simulations of the diesel jet primary atomization from a multihole injector

2017 ◽  
Author(s):  
Charalambos Chasos
Keyword(s):  
High Pressure ◽  
Nozzle Exit ◽  
Cone Angle ◽  
Injection Pressure ◽  
Liquid Jet ◽  
Spray Cone Angle ◽  
Two Phase ◽  
Spray Cone ◽  
Breakup Length ◽  
Jet Breakup

High pressure multi-hole diesel injectors are currently used in direct-injection common-rail diesel engines for the improvement of fuel injection and air/fuel mixing, and the overall engine performance. The resulting spray injection characteristics are dictated by the injector geometry and the injection conditions, as well as the ambient conditions into which the liquid is injected. The main objective of the present study was to design a high pressure multi-hole diesel injector and model the two-phase flow using the volume of fluid (VOF) method, in order to predict the initial liquid jet characteristics for various injection conditions. A computer aided design (CAD) software was employed for the design of the three-dimensional geometry of the assembly of the injector and the constant volume chamber into which the liquid jet emerges. A typical six-hole diesel injector geometry was modelled and the holes were symmetrically located around the periphery of the injector tip. The injector nozzle diameter and length were 0.2 mm and 1 mm, respectively, resulting in a ratio of nozzle orifice length over nozzle diameter L/D = 5. The commercial computational fluid dynamics (CFD) code STAR-CD was used for the generation of the computational mesh and for transient simulations with an Eulerian approach incorporating the VOF model for the two-phase flow and the Rayleigh model for the cavitation phenomenon. Three test cases for increasing injection pressure of diesel injection from the high pressure multi-hole diesel injector into high pressure and high temperature chamber conditions were investigated. From the injector simulations of the test cases, the nozzle exit velocity components were determined, along with the emerging liquid jet breakup length at the nozzle exit. Furthermore, the spray angle was estimated by the average radial displacement of the liquid jet and air mixture at the vicinity of the nozzle exit. The breakup length of the liquid jet and the spray cone angle which were determined from the simulations, were compared with the breakup length and cone angle estimated by empirical equations. From the simulations, it was found that cavitation takes place at the nozzle inlet for all the cases, and affects the fuel and air interaction at the upper area of the spray jet. Furthermore, the spray jet breakup length increases with elapsed time, and when the injection pressure increases both the breakup length and the spray cone angle increase.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.5040

scholarly journals Multiphase simulation of liquid jet breakup using smoothed particle hydrodynamics

2017 ◽  
Vol 28 (04) ◽  
pp. 1750054 ◽  
Author(s):  
Majid Pourabdian ◽  
Pourya Omidvar ◽  
Mohammad Reza Morad
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Multiphase Flows ◽  
Numerical Solutions ◽  
Kernel Functions ◽  
Liquid Jet ◽  
Two Phase ◽  
Breakup Length ◽  
Jet Breakup ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

This paper deals with numerical modeling of two-phase liquid jet breakup using the smoothed particle hydrodynamics (SPH) method. Simulation of multiphase flows involving fluids with a high-density ratio causes large pressure gradients at the interface and subsequently divergence of numerical solutions. A modified procedure extended by Monaghan and Rafiee is employed to stabilize the sharp interface between the fluids. Various test cases such as Rayleigh–Taylor instability, two-phase still water and air bubble rising in water have been conducted, by which the capability of accurately capturing the physics of multiphase flows is verified. The results of these simulations are in a good agreement with analytical and previous numerical solutions. Finally, the simulation of the breakup process of liquid jet into surrounding air is accomplished. The whole numerical solutions are accomplished for both Wendland and cubic spline kernel functions and Wendland kernel function gave more accurate results. Length of liquid breakup in Rayleigh regime is calculated for various flow conditions such as different Reynolds and Weber numbers. The results of breakup length demonstrate in satisfactory agreement with the experimental correlation. Finally, impinging distance and breakup length of a simple multijet setup are analyzed. The two-jet multijet has a longer breakup length than a three-jet one.

Assessment of Models for Liquid Jet Breakup

2008 ◽  
Author(s):  
Paul S. Hutcheson ◽  
John W. Chew ◽  
Rex B. Thorpe ◽  
Colin Young
Keyword(s):  
Failure Modes ◽  
Practical Method ◽  
Liquid Jet ◽  
Test Cases ◽  
Physical Processes ◽  
Two Phase ◽  
Jet Breakup ◽  
Air System ◽  
Potential Mode ◽  
Secondary Air

For many gas turbine architectures a failure modes and effects analysis identifies a potential mode in which failure of an oil transfer pipe could result in oil leakage into the secondary air system. Such an event would result in a complex two-phase interacting flow. The atomisation and transport of the oil within the air system is of interest, but is difficult to predict. Available data for the droplet size resulting from jet breakup in crossflow are limited. A dimensional analysis shows jet breakup in a crossflow to involve many factors. The atomisation process has been shown experimentally to include many physical processes and is still not completely understood. Currently, the most practical method of modelling these breakup processes in sprays is by using a CFD package with a set of sub-models within an Euler-Lagrangian (discrete-droplet) approach. The strengths and weaknesses of each of these sub-models cannot reasonably be tested when used in combination with other approximations to model a spray in crossflow. The purpose of this study was to assess various submodels for liquid breakup with a series of simple test cases.

DETECTION OF AERODYNAMIC EFFECTS IN LIQUID JET BREAKUP AND DROPLET FORMATION

1999 ◽  
Vol 9 (4) ◽  
pp. 331-342 ◽  
Author(s):  
Michael P. Moses ◽  
Steven H. Collicott ◽  
Stephen D. Heister
Keyword(s):  
Droplet Formation ◽  
Liquid Jet ◽  
Jet Breakup
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