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June 11, 2010, 08:24 
Rosin Rammler Distribution

#1 
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Hallo guys,
you can define a RosinRammlerPDF at the sprayProperties of the tutorial aachenbomb (dieselFoam solver). Does anyone knows what the parameter d defines? I think it could be the representative diameter D0.5 = drop diameter such that 50% of total liquid volume is in drops of smaller diameter. So it would be the mass median diameter (MMD). But I dont know for sure.. can someone help me please? Best regards mystix  Sorry, I wanted to post this to the OpenFOAM Forum. Can someone move this thread there? 

June 11, 2010, 19:17 

#2 
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Nam Nguyen
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I believe this is the mean diameter of the particles.


June 14, 2010, 05:58 

#3 
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The Problem is that changing d to lower values (60µm to 20µm) results in a shift of the maximum to the right at a PDFHistogramm:
time after injection 1000ms: d=60µm d=20µm I would like to know how the RosinRammler Distribution works in OF. Do I define the distribution of parcels at the starting and how can I controll it? 

June 14, 2010, 11:00 

#4 
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Joseph Urich
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Hello,
There are source files for a Rosin Rammler pdf in the directory src/thermophysicalModels/pdfs/RosinRammler. I didn't trace the dependencies to be certain if this is called by dieselFoam, but it seems likely. It might offer you more information. 

August 23, 2010, 08:18 

#5 
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X.G. Li
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The RosinRammler distribution is frequently used to describe the particle size distribution of powers of various types and sizes. The function is particularyly suited to representing particles generated by grinding, milling and crushing operations. The conventional RosinRammler function is described by (1)
where R is the retained weight fraction of particles with a diameter greater than D, D is the particle size and is the mean particle size, and n is a measure of the spread of particle sizes. The Cumulative Distribution Function (CDF) is therefore (2) As an additional note, the PDF is: Parameters: Dmmean particle diameternmeasure of the spread of particle sizesDparticle size 

August 23, 2010, 09:12 

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Thank you for answer, CYMa.
I agree, that the cumulative distribution rosin rammler function is right. But I found in J. Madsen Computational and Experimental Study of Sprays from the Breakup of Water Sheets. Dissertation, Faculty of Engineering and Science, Aalborg University, 2006. Page 207, that the probability density function is: What is correct? Where did you get your eq from? Last edited by mystix; August 23, 2010 at 09:32. 

June 17, 2016, 06:23 
parameter d in Rosin Rammler distribution in sprayFoam

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saeed
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Hello CFDmans
This is exactly my question. what is Rosin Rammler parameter d in SprayCloudProperties in sprayFoam solver? Does anyone knows what the parameter d defines and how we can set value for it? Code:
sizeDistribution { type RosinRammler; RosinRammlerDistribution { minValue 1e06; maxValue 0.000120; d 0.000020;//what is this???? n 3; } } Saeed 

June 17, 2016, 09:28 

#8  
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Thien Xuan Dinh
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min and max values is to ensure the range of the particle size within the min and max.
d and n can be referred to Fluent manual http://www.afs.enea.it/project/neptu...ug/node692.htm Quote:


June 17, 2016, 11:47 

#9  
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saeed
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Quote:
Based on this link you referred (Fluent manual), for obtaining d (or dbar) and n we must have particle size data (Mentioned table in this link ), but we want to simulate spray and we don't have any experimental data about particle size before simulation!!! Is there any source or reference for setting d to set value without help of experimental data (like n as i mentioned last post)?? 

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