CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT > Fluent Multiphase

Oil Jet Stability

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 16, 2018, 07:03
Default Oil Jet Stability
  #1
New Member
 
Daniel Gasper
Join Date: Dec 2017
Posts: 1
Rep Power: 0
Gasperle is on a distinguished road
Hello,

i am student from Germany and i am working on my graduation work.
My English is pretty bad, but i have a problem and cant find a solution.
So i decided to do my best and try to explain what i am doing, maybe someone can help me.

From researches i know there are 3 different states of Oil-Jet-Break up. The Jet forms droplets or sprays, depending on the reynolds-number and weber-number. (depending on viscosity, velocity, surface-tension etc.)

Heres my problem, i try to simulate it (plane) with the boundary conditions of the engine, and the Oil-Jet does nothing like that. Its just a laminar Jet right into the cooling-channel. The Jet doesent break up. I uploaded different picture showing my Problem and my input data for the simulation. I dont think that my solution is right and the Jet dont break up.

Maybe someone understands my Problem and can help me. I dont know witch parameter i should change.. i tryed diffrent velocitys, pressure, mass-flows and it wont effect the result. But changes should affect the result. It always looks like a Laminar Jet (left Picture in the Figure) and what i am expecting is a turbulent flow (right picture in the Figure)

My Setup:
(Attachment)
Nodes (73005)
Elements (71904)

Fluent:

Models (Multiphase)
Volume Fraction Parameters: Explicit
Volume Fraction Cutoff: 1e-06
Courant Number: 0.25
Implicit Body Force
Interface Modeling: Sharp
Energy - Off
Viscous - Standard k-e, Standard Wall Function
2D-Space: Axisymmetric

Materials:
engine-oil: Density: 889 kg/m^3
Viscosity: 0.013337 kg/m-s
Air: Density: 1.225 kg/m^3
Viscosity: 1.7894e-05 kg/m-s
Interaction: Surface Tension constant: 0.25

Boundary Conditions:
Inlet: pressure-inlet: 450000 Pa
Turbulent Intensity 0.5%
Hydraulic Diameter 0.003

Outlet: pressure-outlet: Backflow Turbulent Intensity: 8%
Backflow Turbulent Length Scale: 0.3 m
Backflow Volume Fraction: 0

Methods: PISO
Skewness Correction: 0
Neighbor Correction: 3
Skewness-Neighbor Coupling: no
Least Squares Cell Based
Pressure: PRESTO!
Momentum: Second Order Upwind
Volume Fraction: Geo-Reconstruct
Turbulent Kinetic Energy: Second Order Upwind
Turbulent Dissipation Rate: Second Order Upwind
Transient Formulation: First Order Implicit

Controls:
Pressure: 0.9
Density: 0.5
Body Forces: 0.5
Momentum: 0.5
Turbulent Kinetic Energy: 0.5
Turbulent Dissipation Rate: 0.9
Turbulent Viscosity: 0.9

Initialization Methods:
Standard
Compute from: Inlet
Patch: Phase oil
Volume Fraction Value 0

Gradient Adaption: Method: Iso-Value
Volume Fraction
Phase: oil
Refine Threshold: 0.3
Coarsen Threshold: 3
Run:
Time Stepping Method: Variable
Global Courant Number: 0.8
Ending Time: 0.5
Minimum Time Step Size: 1e-09
Maximum Time Step Size: 1e-06

I appreciate every help i can get. Thanks a lot!

Daniel
Attached Images
File Type: jpg Geometry_Parameters.jpg (27.5 KB, 7 views)
File Type: jpg Influence of the inflow mass flow rate.jpg (49.6 KB, 9 views)
Gasperle is offline   Reply With Quote

Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
"Hand" calculation jet fan in the garage mageno Main CFD Forum 3 August 7, 2021 19:09
2D Plane Jet Fluent Solution doug Main CFD Forum 11 February 4, 2019 09:34
Phase change material in oil pan - solidification wsh FLUENT 7 August 14, 2015 06:50
Jet in Supersonic Crossflow, controlling mass flow rate ChrisA OpenFOAM Running, Solving & CFD 3 November 13, 2012 18:20
"stability" of turbulent jet surface location Al FLUENT 0 June 3, 2007 15:44


All times are GMT -4. The time now is 21:14.