Moving mesh in CFX

enr_venkat · March 15, 2010, 08:01

Hi,

I'm currently working on EGR Valve project (Exhaust Gas Recirculation) using ANSYS CFX. I would like to check the heat transfer rate / temperature distribution of EGR valve by running multiple configuration cases namely case1 : Steady state with valve closed ; case 2 : Transient state with valve open at different positions. I know how to setup multiple cases. However I would like to simulate those cases when valve open time is 5 sec and valve closing time is 5 sec. I believe that we could incorporate moving mesh for this application as i went through FSI and Mesh deformation tutorial. Still, I'm not clear with this feature. Should i translate the valve in Design Modeler and then link to CFX solution in project schematic in Workbench? Should i do valve translation to maximum open position and link the project schematics to the same CFX cell in Workbench ? Please help me.

mach000 · March 15, 2010, 12:25

HI,
I'm not sure if I undestood well your problem but, if I have to simulate a case like your I'll create two different domain, in which the inner contains the valve.
In this case, in cfx pre, you can define a subdomain as a moving mesh. Obviously the subdomain will be coincident with the previous inner domain that contains the valve.
Now, in cfx pre, you can define the motion of the subdomain/(inner domain) as you prefer with CEL.
I hope i was able to help you. If not you can write me when you want.
Regards

enr_venkat · March 17, 2010, 07:22

Hi,

How do i create a moving mesh ? I have created two domains namely solid domain that contains valve and fluid domain where fluid flow enters and circulates and exits the domain. Thus i have one EGR Inlet and One EGR Outlet. Opening of Inlet is controlled by a reciprocating valve i.e. plunger. When the plunger pushes down to a max of 4 mm, the fluid flow enters through the gap and exits the domain through EGR outlet. When the plunger retains its original position, it blocks the gap in such a way that it's valve head gets seated. The reciprocation is controlled by the spring and diaphragm and solenoid. For the time being i've extracted the fluid volume with solid volume i.e. Plunger. Now, i would like to run a steady state case with valve closed. In this case, i'm finding it to difficult to mesh cause a gap gets created as the valve head and the fluid volume that surrounds the valve is conicident. Let's not get into this discussion. I would like to take the outputs from steady state case and use it as inputs for transient simulation with valve being opened and closed at different displacements as a function of time. Valve remains open for 5 sec and gets closed in 5 sec. I would like to test these cases and visualise the temperature distribution on plunger due to hot fluid flow. Please do the needful

March 15, 2010, 08:01	Moving mesh in CFX	#1
enr_venkat Member Venkat Join Date: Nov 2009 Posts: 35 Rep Power: 17	Hi, I'm currently working on EGR Valve project (Exhaust Gas Recirculation) using ANSYS CFX. I would like to check the heat transfer rate / temperature distribution of EGR valve by running multiple configuration cases namely case1 : Steady state with valve closed ; case 2 : Transient state with valve open at different positions. I know how to setup multiple cases. However I would like to simulate those cases when valve open time is 5 sec and valve closing time is 5 sec. I believe that we could incorporate moving mesh for this application as i went through FSI and Mesh deformation tutorial. Still, I'm not clear with this feature. Should i translate the valve in Design Modeler and then link to CFX solution in project schematic in Workbench? Should i do valve translation to maximum open position and link the project schematics to the same CFX cell in Workbench ? Please help me.

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March 15, 2010, 12:25		#2
mach000 Member Ciro Cannavacciuolo Join Date: Mar 2009 Posts: 35 Rep Power: 17	HI, I'm not sure if I undestood well your problem but, if I have to simulate a case like your I'll create two different domain, in which the inner contains the valve. In this case, in cfx pre, you can define a subdomain as a moving mesh. Obviously the subdomain will be coincident with the previous inner domain that contains the valve. Now, in cfx pre, you can define the motion of the subdomain/(inner domain) as you prefer with CEL. I hope i was able to help you. If not you can write me when you want. Regards

March 17, 2010, 07:22		#3
enr_venkat Member Venkat Join Date: Nov 2009 Posts: 35 Rep Power: 17	Hi, How do i create a moving mesh ? I have created two domains namely solid domain that contains valve and fluid domain where fluid flow enters and circulates and exits the domain. Thus i have one EGR Inlet and One EGR Outlet. Opening of Inlet is controlled by a reciprocating valve i.e. plunger. When the plunger pushes down to a max of 4 mm, the fluid flow enters through the gap and exits the domain through EGR outlet. When the plunger retains its original position, it blocks the gap in such a way that it's valve head gets seated. The reciprocation is controlled by the spring and diaphragm and solenoid. For the time being i've extracted the fluid volume with solid volume i.e. Plunger. Now, i would like to run a steady state case with valve closed. In this case, i'm finding it to difficult to mesh cause a gap gets created as the valve head and the fluid volume that surrounds the valve is conicident. Let's not get into this discussion. I would like to take the outputs from steady state case and use it as inputs for transient simulation with valve being opened and closed at different displacements as a function of time. Valve remains open for 5 sec and gets closed in 5 sec. I would like to test these cases and visualise the temperature distribution on plunger due to hot fluid flow. Please do the needful