CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

size distribution models in OpenFOAM 4.x

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 28, 2018, 15:30
Default size distribution models in OpenFOAM 4.x
  #1
Member
 
Min Zhang
Join Date: Mar 2017
Posts: 80
Rep Power: 7
minzhang is on a distinguished road
In distributionModel.H, it says:

Class
Foam::distributionModel

Description
A library of runtime-selectable distribution models.

Returns a sampled value given the expectation (nu) and variance (sigma^2)

Current distribution models include:
- exponential
- fixedValue
- general
- multi-normal
- normal
- Rosin-Rammler
- uniform

The distributionModel is tabulated in equidistant nPoints, in an interval.
These values are integrated to obtain the cumulated distribution model,
which is then used to change the distribution from unifrom to
the actual distributionModel.



My goal: Set a volume uniform particle size distribution.

my Questions:

Q1. What is "general distribution", in this thread
Size Distribution Models - Spray Modelling
Chrisi1984 gave a general distribution example, I want to make sure whether the second column is the number fraction of the corresponding particle size in the first column.

Q2. The "uniform distribution" is a uniform DISTRIBUTION between minValue and maxVaue, yes? My point is it is not a single particle size, it is a distribution. If we choose to use the uniform distribution, we only need to give "minValue" and "maxValue".Then, my question is how many particle sizes (which is nPoints in the above copied distributionModel.H description, yes?) are used?

Q3. For my goal "a mass/volume uniform PSD (since the particles have the same density, volume fraction is the same as mass fraction)", which is the efficient option? Right now, I think the general distribution could be the solution.

Thanks and best regards,
Min
minzhang is offline   Reply With Quote

Old   March 30, 2018, 18:10
Default
  #2
Member
 
Min Zhang
Join Date: Mar 2017
Posts: 80
Rep Power: 7
minzhang is on a distinguished road
Quote:
Originally Posted by minzhang View Post
In distributionModel.H, it says:

Class
Foam::distributionModel

Description
A library of runtime-selectable distribution models.

Returns a sampled value given the expectation (nu) and variance (sigma^2)

Current distribution models include:
- exponential
- fixedValue
- general
- multi-normal
- normal
- Rosin-Rammler
- uniform

The distributionModel is tabulated in equidistant nPoints, in an interval.
These values are integrated to obtain the cumulated distribution model,
which is then used to change the distribution from unifrom to
the actual distributionModel.



My goal: Set a volume uniform particle size distribution.

my Questions:

Q1. What is "general distribution", in this thread
Size Distribution Models - Spray Modelling
Chrisi1984 gave a general distribution example, I want to make sure whether the second column is the number fraction of the corresponding particle size in the first column.

Q2. The "uniform distribution" is a uniform DISTRIBUTION between minValue and maxVaue, yes? My point is it is not a single particle size, it is a distribution. If we choose to use the uniform distribution, we only need to give "minValue" and "maxValue".Then, my question is how many particle sizes (which is nPoints in the above copied distributionModel.H description, yes?) are used?

Q3. For my goal "a mass/volume uniform PSD (since the particles have the same density, volume fraction is the same as mass fraction)", which is the efficient option? Right now, I think the general distribution could be the solution.

Thanks and best regards,
Min



My own answers:
Q1: The second column is the volume fraction/probability, not number fraction.

Q2: I have no answer currently.

Q3: "uniform" distributionModel would be the most efficient option. This is because it is uniform mass fraction.

Any comments would be very appreciated!
minzhang is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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
Frequently Asked Questions about Installing OpenFOAM wyldckat OpenFOAM Installation 1 June 24, 2021 20:34
using chemkin JMDag2004 OpenFOAM Pre-Processing 2 March 8, 2016 22:38
New OpenFOAM Forum Structure jola OpenFOAM 2 October 19, 2011 06:55
Cross-compiling OpenFOAM 1.7.0 on Linux for Windows 32 and 64bits with Mingw-w64 wyldckat OpenFOAM Announcements from Other Sources 3 September 8, 2010 06:25
Particle Size Distribution with R-R fails? HP FLUENT 6 May 19, 2005 06:35


All times are GMT -4. The time now is 17:09.