simulating hydraulic amplifier in ansys or ansys workbench

[hdssndss]

I want to simulate a simple hydraulic amplifier in Ansys or Ansys workbench. It is supposed to have an input cylinder with a larger cross sectional area, a hydraulic fluid, and an output cylinder with a smaller cross sectional area. When a displacement is applied to the input cylinder, the output displacement will be amplified. I don't know whether ansys workbench recognizes an assembly and how to couple the solid and the fluid elements to transfer motion? Please help me out.

 

[hydromech]

The device you want to replicate is called an intensifier.

What do you want to simulate?

Ansys will analyse material deformation or CFD of the flow into the intensifier. The relationship between fluid volume and velocity is an easy hand calculation.

CAD simulation can be done in most CAD packages and is again based on fluid properties.

 

[hdssndss]

Thanks for replying.

I want to verify the theoretical amplification factor (input area/ output area) using Ansys.

Then I want to incorporate the effect of air entrapment in the hydraulic fluid and determine how much it will lower the amplification factor.

 

[hydromech]

Assuming that you intend to use Ansys for the FEA, it can tell you the stress and or strain in the material as a result of the internal hydraulic pressure.

The amplification is purely a ratio of the areas within the intensifier.

Input pressure x input area = output pressure x output area.

For 10 : 1 pressure intensification, there would be the ratio for the areas within the intensifier.

Air absorbed into oil does adjust the bulk modulus of the, but you need to know the fluid properties and temperature to accurately predict the additional compression. Gas compression and the volume need to be calculated.

What part on Ansys are you thinking about using?

 

[hydtools]

hydromech,
The desription in the original post is not an intensifier. It is a motion amplifier in that for a small input motion to the large cylinder rod there is a larger output motion of the small cylinder rod. The large cylinder is the input, delivers fluid to the small cylinder, the small cylinder is the output. No?

If the rod of the large cylinder is connected to the rod of the small cylinder and hydraulic pressure is applied to the large cylinder then high pressure is generated in the small cylinder. Then it is an intensifier.

Ted

 

[hydromech]

Amplifier...intensifier...whichever.

Ansys is not the way to do it me thinks.

 

[hdssndss]

I want to use Ansys FSI(fluid solid interface) to simulate the interaction between the input and output cylinders with the hydraulic fluid.

I've already imported the geometry into ansys workbench and defined the contacts between the cylinders and their housing. What I need now is to define the fluid properties and setup the interface between the solids and the fluid.

This is my first time doing this kind of simulation so I don't know how difficult it is going to be. And the help on Ansys FSI is not very comprehensive.

Any suggestions/comments?

Thanks.

 

[hydromech]

OK then...now that's all established. I didn't read the original post correctly...sorry.

Ansys can recognise and handle assemblies, you just need to define the contact regions between the parts.

You will need to load the fluid parameters to determine the output displacement relative to the input. The volume of air trapped in the fluid will obviously make a big difference to the results as will the temperature.