Problem: hollow cone spray with TAB model.

chenhu · July 1, 2009, 08:33

I am trying to simulate hollow cone spray with TAB breakup model, but the result is very strange. There is a finger in the spray. When I switch off the TAB model, it looks normal.
I compared the OpenFOAM TAB implementation with KIVA. The only difference is that the droplet velocity and direction is not updated after breakup in the TAB.C file. I don't know if this is the reason for the strange droplet distribution.
Can anybody tell me where the droplet velocity and direction is updated in the OpenFOAM?
What might be the cause for this problem?

This is the droplet distribution with TAB breakup.
http://lh3.ggpht.com/_OYtXHb5wD_0/Sk...c/s640/tab.jpg

This is the droplet distribution without TAB breakup.
http://lh3.ggpht.com/_OYtXHb5wD_0/Sk.../s640/NoBu.jpg

schmidt_d · July 3, 2009, 11:25

Chenhu,
It looks to me like the finger is comprised of very small droplets formed by the TAB model's predicted breakup. Gas flow in these types of spray is from the outside towards the centerline of the spray. These small droplets are convected to the centerline while the larger droplets continue on their ballistic trajectory. The prediction of very small droplets is a common criticism of the TAB model, though I still use it myself.
-David

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
problem with UDF for (v2-f) turbulence model in fluent	artemiss1984	Fluent UDF and Scheme Programming	6	January 17, 2014 05:50
problem of dynamic mesh for a piston model	pipin	Fluent UDF and Scheme Programming	2	August 2, 2010 14:35
Problem in Herschel-Bulkely model	emad	FLUENT	0	May 20, 2009 14:20
Problem with hypersonic blunt cone solution	Bharath Hebbal	FLUENT	0	February 15, 2008 02:07
problem with MFR model for multiphase mixing tanks	Srinivas	Main CFD Forum	1	November 7, 2005 14:16

July 3, 2009, 11:25		#2
schmidt_d Member David P. Schmidt Join Date: Mar 2009 Posts: 71 Rep Power: 17	Chenhu, It looks to me like the finger is comprised of very small droplets formed by the TAB model's predicted breakup. Gas flow in these types of spray is from the outside towards the centerline of the spray. These small droplets are convected to the centerline while the larger droplets continue on their ballistic trajectory. The prediction of very small droplets is a common criticism of the TAB model, though I still use it myself. -David