Particle Flow Rate injection specification using DEM

sarahscullion · March 1, 2021, 10:16

Hi,

Quite new to Star CCM+ - sorry if I have explained this badly.

I am trying to inject particles into a pipe once the flow is fully developed. Is there a way to only inject a certain number of particles? I currently am using particle flow rate specification so that I can inject once the flow is fully developed. I have tried modifying the condition from the DEM conveyor tutorial "$Time < 0.5 ? 100 : 0" to be "$Time > 0.5 ? 1 : 0", although this is still too many particles - as it continuously injects them . Is there a way to modify it so that it only injects say 2 particles per injection point after a set amount of time? Or even only injects them between a certain time frame?

Let me know if you need extra information. Any help would be greatly appreciated!

Thanks

Nabuchadresar · March 3, 2021, 15:11

Hi, you can choose type: "Random Injector"
>>"Condition node"
>>> "Particle packing specification" and set "particles count"

>> "Values node"
>>> "Number of particle" and set the number of particles you desire.

On this way you set the amount of particles you need. But the particles will appear randomly inside your pipe (if you set the pipe as input)

StarCCM+ has some different types of injectors, you can play with them to solve you problem.

In "injection point" you can choose
>>"Condition node"
>>> "Flow rate specification" and set "particles flow rate"

>> "Values node"
>>> "Particle flow rate" and set the number of particles (by second) you desire too.

But here you choose how many particles will be injected per second.

I hope I understand your problem.

March 1, 2021, 10:16	Particle Flow Rate injection specification using DEM	#1
sarahscullion New Member Sarah Scullion Join Date: Mar 2021 Posts: 1 Rep Power: 0	Hi, Quite new to Star CCM+ - sorry if I have explained this badly. I am trying to inject particles into a pipe once the flow is fully developed. Is there a way to only inject a certain number of particles? I currently am using particle flow rate specification so that I can inject once the flow is fully developed. I have tried modifying the condition from the DEM conveyor tutorial "$Time < 0.5 ? 100 : 0" to be "$Time > 0.5 ? 1 : 0", although this is still too many particles - as it continuously injects them . Is there a way to modify it so that it only injects say 2 particles per injection point after a set amount of time? Or even only injects them between a certain time frame? Let me know if you need extra information. Any help would be greatly appreciated! Thanks

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March 3, 2021, 15:11		#2
Nabuchadresar Member André Luiz Moura Silva Moreira Join Date: Apr 2015 Location: Brazil Posts: 40 Rep Power: 11	Hi, you can choose type: "Random Injector" >>"Condition node" >>> "Particle packing specification" and set "particles count" >> "Values node" >>> "Number of particle" and set the number of particles you desire. On this way you set the amount of particles you need. But the particles will appear randomly inside your pipe (if you set the pipe as input) StarCCM+ has some different types of injectors, you can play with them to solve you problem. In "injection point" you can choose >>"Condition node" >>> "Flow rate specification" and set "particles flow rate" >> "Values node" >>> "Particle flow rate" and set the number of particles (by second) you desire too. But here you choose how many particles will be injected per second. I hope I understand your problem.