transient spray modelling

anand3984 · May 14, 2012, 03:20

hi
I am beginner in spray modelling. I am trying to solve transient spray injected in still air using CFX-11. i have created particle injection region and injecting the droplet with blob method. also trying to simulate secondary breakup with TAB model. But when I am specifying the number rate (number of position) to any value like 300/s or 3000/s i am getting only 1 droplet entered in domain (solver panel) also the initial iteration number for which it should not inject the droplet, i am specifying 1000, even it is injecting from first time step.
can any body help me out how to control this droplet number in transient calculations

Timon · May 16, 2012, 04:45

If you're doing transient particle tracking and you're specifying the droplet injection rate (in droplets per second), then the amount of droplet injected per timestep are of course dependent on your time step.

E.g. if you're timestep is (1/300) s and you're injecting 300 droplets per second, then you would see 1 droplet being introduced into your domain every timestep.

anand3984 · May 23, 2012, 06:03

Thanx for your reply.......i got it.
Can we model Collision and Colescence in lagrangian framework for modelling the spray in CFX-11

May 14, 2012, 03:20	transient spray modelling	#1
anand3984 New Member anand Join Date: May 2012 Posts: 2 Rep Power: 0	hi I am beginner in spray modelling. I am trying to solve transient spray injected in still air using CFX-11. i have created particle injection region and injecting the droplet with blob method. also trying to simulate secondary breakup with TAB model. But when I am specifying the number rate (number of position) to any value like 300/s or 3000/s i am getting only 1 droplet entered in domain (solver panel) also the initial iteration number for which it should not inject the droplet, i am specifying 1000, even it is injecting from first time step. can any body help me out how to control this droplet number in transient calculations

May 23, 2012, 06:03	spray modelling	#3
anand3984 New Member anand Join Date: May 2012 Posts: 2 Rep Power: 0	Thanx for your reply.......i got it. Can we model Collision and Colescence in lagrangian framework for modelling the spray in CFX-11

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May 16, 2012, 04:45		#2
Timon Member Join Date: Mar 2009 Posts: 44 Rep Power: 17	If you're doing transient particle tracking and you're specifying the droplet injection rate (in droplets per second), then the amount of droplet injected per timestep are of course dependent on your time step. E.g. if you're timestep is (1/300) s and you're injecting 300 droplets per second, then you would see 1 droplet being introduced into your domain every timestep.