Grade-Efficiency Curve for a Gas Cyclone

pietro_lopo · March 23, 2020, 08:05

Understood. Then, having just the numbers of particles in inlet and outlet, how do you suggest to calculate the grade efficiency curve? and so having the efficiency of my cyclone in function of the particle size?
I.e. shall i calculate the separation efficiency for 3e-06 m particle like this:
number of escaped particle/ number of injected particle?

vinerm · March 23, 2020, 09:42

Taking just the ratio of numbers would give an idea but not correct value. This would be correct if and only if all particles are of same size and each parcel is representing same number of particles. A better approach would be to look at the mass of particles. Take the ratio of particle mass at outlet to particle mass at inlet.

pietro_lopo · March 23, 2020, 10:09

That was what i was thinking about but the only thing that i've been able to visualize is the mass flow rate in inlet and outlet, (in kg/s) , and i don't know how to have information about the mass fraction in relation with the particle's size. how can i get this information?

vinerm · March 23, 2020, 10:15

Mass flow is for continuous phase. For the particles, it is all included in the sample file. Open the sample files in the text editor you use, vi, or textpad or notepad++, or any other. Or you may directly load those in Gnuplot or Excel.

pietro_lopo · March 23, 2020, 10:38

just opened one of the .dpm file and i can see all the particles in that section and all these proprieties:
(x y z u v w diameter t
mass-flow mass frequency time name)

Now, for example, for the 3e-06 particles, should I calculate the mass of all these particles in inlet , and then the mass of all these particles in the out_dust and then i can calculate the mass fraction?

vinerm · March 23, 2020, 10:41

mass-flow shows the mass flow represented by that particular parcel or injection whereas mass is the mass of individual particle. frequency is their ratio. So, you can add mass-flow for all the rows for outlet as well as inlet and then take their ratio.

pietro_lopo · March 23, 2020, 12:25

well doing like this i will obtain the overall efficiency. if you can suggest me how to obtain a distribution like this (in the images attached), in order to plot the curve in the second image. Immagine.png

Immagine2.png

vinerm · March 23, 2020, 12:32

The sample file also has diameter given. Just sum the values for given diameters only. That will give you as many number as many diameters you have.

March 23, 2020, 09:42	Separation Efficiency	#22
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 36	Taking just the ratio of numbers would give an idea but not correct value. This would be correct if and only if all particles are of same size and each parcel is representing same number of particles. A better approach would be to look at the mass of particles. Take the ratio of particle mass at outlet to particle mass at inlet. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

March 23, 2020, 10:15	Mass Flow of Particles	#24
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 36	Mass flow is for continuous phase. For the particles, it is all included in the sample file. Open the sample files in the text editor you use, vi, or textpad or notepad++, or any other. Or you may directly load those in Gnuplot or Excel. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

March 23, 2020, 10:41	.dpm file	#26
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 36	mass-flow shows the mass flow represented by that particular parcel or injection whereas mass is the mass of individual particle. frequency is their ratio. So, you can add mass-flow for all the rows for outlet as well as inlet and then take their ratio. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

March 23, 2020, 12:32	Diameter Distribution	#28
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 36	The sample file also has diameter given. Just sum the values for given diameters only. That will give you as many number as many diameters you have. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[Gmsh] Vertex numbering is dense	KateEisenhower	OpenFOAM Meshing & Mesh Conversion	7	August 3, 2015 10:49
meshing of a compound volume in GMSH	shawn3531	OpenFOAM	4	March 12, 2015 10:45
Two-Phase Buoyant Flow Issue	Miguel Baritto	CFX	4	August 31, 2006 12:02
Gas pressure question	Dan Moskal	Main CFD Forum	0	October 24, 2002 22:02
Modelling Industrial cyclone behaviour	Günther Hasse	Main CFD Forum	3	October 12, 1999 19:34

March 23, 2020, 08:05		#21
pietro_lopo New Member Pietro Loporcaro Join Date: Mar 2020 Posts: 22 Rep Power: 6	Understood. Then, having just the numbers of particles in inlet and outlet, how do you suggest to calculate the grade efficiency curve? and so having the efficiency of my cyclone in function of the particle size? I.e. shall i calculate the separation efficiency for 3e-06 m particle like this: number of escaped particle/ number of injected particle?

March 23, 2020, 10:09		#23
pietro_lopo New Member Pietro Loporcaro Join Date: Mar 2020 Posts: 22 Rep Power: 6	That was what i was thinking about but the only thing that i've been able to visualize is the mass flow rate in inlet and outlet, (in kg/s) , and i don't know how to have information about the mass fraction in relation with the particle's size. how can i get this information?

March 23, 2020, 10:38		#25
pietro_lopo New Member Pietro Loporcaro Join Date: Mar 2020 Posts: 22 Rep Power: 6	just opened one of the .dpm file and i can see all the particles in that section and all these proprieties: (x y z u v w diameter t mass-flow mass frequency time name) Now, for example, for the 3e-06 particles, should I calculate the mass of all these particles in inlet , and then the mass of all these particles in the out_dust and then i can calculate the mass fraction?

March 23, 2020, 12:25		#27
pietro_lopo New Member Pietro Loporcaro Join Date: Mar 2020 Posts: 22 Rep Power: 6	well doing like this i will obtain the overall efficiency. if you can suggest me how to obtain a distribution like this (in the images attached), in order to plot the curve in the second image. Immagine.png Immagine2.png