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How to make vertical lift check valve

Valued Contributor
Valued Contributor
I'd like to create vertical lift check valve like attached image.
recently I found demo model,(Pneumatic check valve $AME/demo/lib/PCD/PCD_CheckValve.ame)
But I use Two phase flow library. So can I make same check valve using tpf library?
 
 
12 REPLIES 12

Re: How to make vertical lift check valve

Siemens Phenom Siemens Phenom
Siemens Phenom

Yes, just replace the piston and the flapper with their equivalent from the tpf (two-phase flow) library.

It will look like this:

image.png

Re: How to make vertical lift check valve

Siemens Phenom Siemens Phenom
Siemens Phenom
And don't forget to apply gravity to the mass (parameter: inclination ... should be +/- 90 degrees) with the correct sign.

Re: How to make vertical lift check valve

Valued Contributor
Valued Contributor

I tried to create the model but it doesnt work well.

I have several question about flapper nozzle and check valve model.

My understanding about flapper valve is right? according 1st slide.

and where does the flapper diameter indicate(= Disk diameter)?

 

01.png02.png

Re: How to make vertical lift check valve

Siemens Phenom Siemens Phenom
Siemens Phenom

The flapper component is like this schematic (extracted from the Help of the component).

It is a generic component, rods can be zero if necessary.

This is not the diagram you have copied with a nozzle and a flapper on a pivot junction.

image.png

The check valve:

image.png

 

 

For the questions:

1. The diameter of the flapper is the diameter of the green part.

2. Lift: the minimal lift can be zero (flapper on its support). the maximum lift should be for the compressed spring. It's not very important to get this as an approximation. The lift itself will be computed during the simulation.

3.For your case, the rod diameter needs to be zero. The whole surface of the flapper is seeing the fluid pressure (including the little rods both ends).

 

In your screenshot, the flapper will create an output force at port 4 due to:

- external force applied at port 3, this is usually zero

- [EDIT] pressure at port 2, multiplied by the active area of the flapper (area of diameter - area of rod) a combination of pressures at port 1 and 2 applied to active areas.

This force will then be sent to the piston, through port 4, the piston will add the force equal to pressure*area and will apply this total force to the connected mass which will compute its position and velocity depending on external force. This is how the flapper eventually moves.

 

Finally, yes in this case both diameters are the same.

The piston diameter represents the left side of the flapper, the flapper diameter represents the right side of the flapper (on my picture). There is no rod on the left side either.

Re: How to make vertical lift check valve

Valued Contributor
Valued Contributor

I greatly appreciate your kindness.

I could understand the mechanism about flapper.

I'd like to ask another question,

If the xlist=0mm, Port 2 pressure multiplied by the active area of the flapper.

Is it di area?  (due to dr=0)

 

My model seems to become Check valve by change df=piston diameter.

but the flow amount was too much, I changed di smaller.

In this case there is oscillation, can I change the total flow amount by di? 

why does this oscillation happen?

 

di=20mm but flow was 600kg/h too much compared test result

04.png

 

di=10 but oscillation occured

03.png

Re: How to make vertical lift check valve

Siemens Phenom Siemens Phenom
Siemens Phenom

You're welcome.

 

@naoki1 wrote:
[...]

I'd like to ask another question,

If the xlist=0mm, Port 2 pressure multiplied by the active area of the flapper.

Is it di area?  (due to dr=0)

 

It depends on the settings of the flapper component.

There are two options which allows to choose the way the force is computed, "pressure force contribution on the flapper seat at zero lift" and "pressure acting in the flapper seat area"

image.png

 

When you set "pressure force contribution on the flapper seat at zero lift" to "no" then it will behave as you said: pressure at port 2 only acting on di. If it was yes the pressure at port 2 still act on di and pressure at port 1 acts on (df-di).

 

The other parameter (constant/gradient/transition) will also be important during the motion of the flapper as this will change which pressure is acting between di and (df-di). Check the help of the component (right click the flapper and select Help) for more information about this option.

 

 

Re: How to make vertical lift check valve

Siemens Phenom Siemens Phenom
Siemens Phenom

@naoki1 wrote:

[...]

In this case there is oscillation, can I change the total flow amount by di? 

why does this oscillation happen?

 [...]

 

 


Try using a spring and damper instead of a spring only and by tuning the damping coefficient you may get rid of the oscillations. The damping is due to the flapper moving in a fluid.

Re: How to make vertical lift check valve

Valued Contributor
Valued Contributor

Thank you so much! I could figure out this more deeply.

To begin with, the reason why I made this model is that

it was different from actual test result 

when we made this mechanism by Variable orifice.

Does this flapper component take account of dynamic pressure?

Re: How to make vertical lift check valve

Siemens Phenom Siemens Phenom
Siemens Phenom

In this library all the variables are total quantities (dynamic + static). Gravity is not considered.

 

If you want more details about the library, its assumptions or equations... please check the user manual of the library.

It is available from Amesim/Help/Library Documentation:

image.png