# QMOM Boundary Values

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 October 27, 2014, 10:37 QMOM Boundary Values #1 New Member   Laurens Tijsseling Join Date: Oct 2014 Location: Delft Posts: 4 Rep Power: 5 When using the QMOM method to solve the PBE's Fluent requires boundary values for each moment (0 to 5). After a thorough literature research I haven't been able to find how to compute these boundary values. Anyone with a solution?

September 23, 2015, 21:50
#2
New Member

Meng Liu
Join Date: Sep 2015
Posts: 14
Rep Power: 4
Quote:
 Originally Posted by l.tijsseling When using the QMOM method to solve the PBE's Fluent requires boundary values for each moment (0 to 5). After a thorough literature research I haven't been able to find how to compute these boundary values. Anyone with a solution?
Now,do you know how to set boundary values?

 October 9, 2015, 06:23 #3 New Member   Laurens Tijsseling Join Date: Oct 2014 Location: Delft Posts: 4 Rep Power: 5 Yes I did! Have you found them yet or do you need help?

 October 9, 2015, 07:13 #4 New Member   Meng Liu Join Date: Sep 2015 Posts: 14 Rep Power: 4 Yes,I need! What's the principle to set the BC values of moments. Did your simulation results coincide with your expectations? Did you ever try DQMOM method?

 October 9, 2015, 07:20 #5 New Member   Meng Liu Join Date: Sep 2015 Posts: 14 Rep Power: 4 Yes,I need! What's the principle to set the BC values of moments. Did your simulation results coincide with your expectations? Did you ever try DQMOM method?

 October 9, 2015, 08:41 #6 New Member   Laurens Tijsseling Join Date: Oct 2014 Location: Delft Posts: 4 Rep Power: 5 They did eventually agree with the expected results. I have not used the DQMOM, as I was only working with two phases. You know moment-0 is the number of bubbles, moment-1 the total length, moment-2 the total area and moment-3 the total volume. You need these values in #/m3. The parameter you decide is the diameter of the bubble. Please note that moment-3 has the same value regardless of the bubble diameter. As I only specified boundary conditions at the inlet, moment-0 was 1/volume one bubble and the others can be deduced from there. I achieved most succes using the Luo coalescence and break up kernel.

 October 9, 2015, 08:58 #7 New Member   Meng Liu Join Date: Sep 2015 Posts: 14 Rep Power: 4 Sorry, I can't understand what you mean by the following. Can you explain it in detail? “You need these values in #/m3. The parameter you decide is the diameter of the bubble. Please note that moment-3 has the same value regardless of the bubble diameter. As I only specified boundary conditions at the inlet, moment-0 was 1/volume one bubble and the others can be deduced from there”

 October 9, 2015, 09:13 #8 New Member   Laurens Tijsseling Join Date: Oct 2014 Location: Delft Posts: 4 Rep Power: 5 I'll send you a PM for contact details.

 October 9, 2015, 21:02 #9 New Member   Meng Liu Join Date: Sep 2015 Posts: 14 Rep Power: 4 OK, thank you. Or you can send me an email. My email is nel86@qq.com.

December 5, 2015, 02:07
#10
New Member

wubin
Join Date: Dec 2015
Posts: 5
Rep Power: 4
Quote:
 Originally Posted by l.tijsseling When using the QMOM method to solve the PBE's Fluent requires boundary values for each moment (0 to 5). After a thorough literature research I haven't been able to find how to compute these boundary values. Anyone with a solution?
Hellow, have you meet the trouble about adding correction term into sorce term? I don't know how to add it reasonablely.

 May 5, 2016, 00:00 #11 New Member   Join Date: May 2016 Posts: 4 Rep Power: 3 Up this topic Really need the answer tho

November 14, 2017, 02:57
QMOM boundary moment values
#12
New Member

Chuchu Liang
Join Date: Nov 2017
Posts: 1
Rep Power: 0
Quote:
 Originally Posted by l.tijsseling They did eventually agree with the expected results. I have not used the DQMOM, as I was only working with two phases. You know moment-0 is the number of bubbles, moment-1 the total length, moment-2 the total area and moment-3 the total volume. You need these values in #/m3. The parameter you decide is the diameter of the bubble. Please note that moment-3 has the same value regardless of the bubble diameter. As I only specified boundary conditions at the inlet, moment-0 was 1/volume one bubble and the others can be deduced from there. I achieved most succes using the Luo coalescence and break up kernel.
You mean only the moment-0(1/one bubble volume) would be specified at the inlet when the DQMOM is used? Is the diameter of the bubble an averaged one? If the diameter of bubbles is a size distribution, how to set the boundary values? Thanks in advance

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