Modelling Valves That Aren't in the Software

JJM

I am trying to model a system that contains a complex valve system and I cannot find a valve that looks like the one in my schematic (shown below). I was wondering how much it would matter using a similar valve rather than the identical one. 

In addition to this, I am looking to control the flow of this valve using a potentiometer circuit and I am really struggling to get proper results. Below I have linked a picture of the valve I want to model I aswell as my model to allow for any viewers to help correct my potentiometer control.

Any sort of help is appreciated as I am sure it is just the fact of me being new to the program.

Thanks.

Desired Proportional Valve

 

RSGarciarivas

Hi AJ,

What's the issue with your potentiometer control? Is there a specific settling speed for which you would like to design or would you like to feed a time-varying signal to the motor?

With the current parameters, I see the motor settles down at around 31 rad/s after 30 seconds of simulation. Have you increased the simulation time on your side?

Rafael

JJM

Rafael Sánchez Garciarivas_20484 said:

Hi AJ,

What's the issue with your potentiometer control? Is there a specific settling speed for which you would like to design or would you like to feed a time-varying signal to the motor?

With the current parameters, I see the motor settles down at around 31 rad/s after 30 seconds of simulation. Have you increased the simulation time on your side?

Rafael

Hey Rafael, I appreciate the response!

The main issue I am having is controlling the flow through the system with the potentiometer itself. I am unsure at what valves/sensors to use in order to do so. Currently with that proportional valve I get two different responses when varying the resistance in the potentiometer, which makes sense as the valve has two positions. I was wondering if there is a way to get a different response for each value of resistance (ie. as I turn the potentiometer in a real life setting, the speed of the motor would change in proportion to it).  As for settling speed, 50 rad/s is the max speed of the motor when running constantly so nothing exceeding that. Ideally the potentiometer could vary the speed of the motor from 0 to 50 rad/s or some upper limit below that.

 

In terms of increasing time in the simulation, I have done so but it never moved much above 31 rad/s. It maybe hops up by .5 rad/s but never much more than that.

 

Cheers,

 

AJ

 

 

RSGarciarivas

AJ Mitchell said:

Hey Rafael, I appreciate the response!

The main issue I am having is controlling the flow through the system with the potentiometer itself. I am unsure at what valves/sensors to use in order to do so. Currently with that proportional valve I get two different responses when varying the resistance in the potentiometer, which makes sense as the valve has two positions. I was wondering if there is a way to get a different response for each value of resistance (ie. as I turn the potentiometer in a real life setting, the speed of the motor would change in proportion to it).  As for settling speed, 50 rad/s is the max speed of the motor when running constantly so nothing exceeding that. Ideally the potentiometer could vary the speed of the motor from 0 to 50 rad/s or some upper limit below that.

 

In terms of increasing time in the simulation, I have done so but it never moved much above 31 rad/s. It maybe hops up by .5 rad/s but never much more than that.

 

Cheers,

 

AJ

 

 

Hi AJ,

I'm thinking you could control the flow using the potentiometer and a pressure relief valve or a variable resistor.

I've created a small example using a PR valve so you can look at it.

Rafael

JJM

Rafael Sánchez Garciarivas_20484 said:

Hi AJ,

I'm thinking you could control the flow using the potentiometer and a pressure relief valve or a variable resistor.

I've created a small example using a PR valve so you can look at it.

Rafael

Hey Rafael, quick question.

 

On that PRV model, how did you create the little reference arrow inside the potentiometer that comes from an input?

I have attached a picture as well.

RSGarciarivas

AJ Mitchell said:

Hey Rafael, quick question.

 

On that PRV model, how did you create the little reference arrow inside the potentiometer that comes from an input?

I have attached a picture as well.

Hi AJ,

That little arrow is an interface used for connecting explicit blocks (those blocks from the standard Activate library) and implicit blocks (physics-based, like those from the Modelica and the Hydraulics library).

When you create a link between implicit and explicit blocks, interfaces will be automatically created. If you want to manually add one to your diagram, go to the Standard Activate Library in the palette browser > Interfaces > ToModelica and FromModelica.

Rafael