material defining problem

ibadullah safdar · March 28, 2016, 13:16

Dear all,
I am doing CFX modeling of a venturi nozzle. For this, there are two nozzles, one is the bigger and the other one is attached on its throat area. so the problem is that i have used one material point of a big nozzle and create a mesh of it. Now i face problem in defining different materials for these two nozzles. The air will pass through big nozzle and water will pass through small one.
I have read CFX threats of previous people. I understand up to some extent that i have to create separate material points and two bodies but question arise in my mind that when smaller nozzle is not merged with bigger nozzle then there are two boundaries created, of which one is inlet and other is outlet but under outlet there is a body of bigger nozzle (throat area). if i specified one boundary as inlet and other one as outlet then what i specify to the surface body of bigger nozzle, so how the water will flow into the throat area.
Please help me out

Regards,
IBA

Opaque · March 28, 2016, 14:43

You may need to sketch your model, and how those two nozzles interact. Is there mixing of the air and water ?

If there is mixing, is water liquid or gas phase ? For liquid water and air mixture, you may need to read how to setup a multiphase problem in ANSYS CFX and understand the different sub-models. For water vapor and air mixing, you can get away with creating a single multicomponent mixture of air and water, and similarly read how to setup such case.

Hope the above helps,

ibadullah safdar · March 28, 2016, 16:21

Opaque thanks for ur response
The mixing will be done in throat area where water and air meets.

ibadullah safdar · March 28, 2016, 16:24

Opaque Please check the pic it will clear u more

March 28, 2016, 13:16	material defining problem	#1
ibadullah safdar New Member Ibadullah Join Date: Jan 2016 Posts: 21 Rep Power: 10	Dear all, I am doing CFX modeling of a venturi nozzle. For this, there are two nozzles, one is the bigger and the other one is attached on its throat area. so the problem is that i have used one material point of a big nozzle and create a mesh of it. Now i face problem in defining different materials for these two nozzles. The air will pass through big nozzle and water will pass through small one. I have read CFX threats of previous people. I understand up to some extent that i have to create separate material points and two bodies but question arise in my mind that when smaller nozzle is not merged with bigger nozzle then there are two boundaries created, of which one is inlet and other is outlet but under outlet there is a body of bigger nozzle (throat area). if i specified one boundary as inlet and other one as outlet then what i specify to the surface body of bigger nozzle, so how the water will flow into the throat area. Please help me out Regards, IBA

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March 28, 2016, 14:43		#2
Opaque Senior Member Join Date: Jun 2009 Posts: 1,880 Rep Power: 33	You may need to sketch your model, and how those two nozzles interact. Is there mixing of the air and water ? If there is mixing, is water liquid or gas phase ? For liquid water and air mixture, you may need to read how to setup a multiphase problem in ANSYS CFX and understand the different sub-models. For water vapor and air mixing, you can get away with creating a single multicomponent mixture of air and water, and similarly read how to setup such case. Hope the above helps,

March 28, 2016, 16:21		#3
ibadullah safdar New Member Ibadullah Join Date: Jan 2016 Posts: 21 Rep Power: 10	Opaque thanks for ur response The mixing will be done in throat area where water and air meets.