How can I accurately model a digital control valve without physical testing?

[shubham nerkar]

hi,
i want to derive a model of digital control valve. i don't have physical valve with me. still i have to develop such a simulator which can behave the same as the digital control valve.
the working concept of digital control valve is little bit different than normal control valve.
here is the working of the valve
http://www2.emersonprocess.com/siteadmincenter/PM Daniel Documents/788DVControlValve-DS.pdf

can any1 help me out how to do it?

 

[russ_watters]

What, exactly, about the valve are you trying to model? Flow rate and pressure drop vs position? Can't you just use the catalogued performance map as your model?

 

[shubham nerkar]

the main value is controlled by the 2 solenoid valves N.O and N.C. which actually uses either high pressure or low pressure available across the valve. so i want a mathematical model for the behavior of valve. if the NO and NC are not energized the valve will close. suppose initially valve is full open, so if i made it to close in how much time and how much distance will the piston covers and finally the flow rate profile .

 

[JBA]

As someone involved in the design, engineering and testing of modulating ASME Section 8 Pressure Vessel Code PRV's (Pressure Relief Valves) I can tell you that due to the complex flow path in both right angle and angle body valves the only way to get an accurate flow vs. lift profile for a given valve configuration is by flow testing. Even in the case of a given valve configuration the flow vs lift profile will vary for different sizes of that configuration.

I developed a series of simulation programs such as you desire for our product lines and all of those have programs have required equations based upon curve fitting of actual flow test results for each valve configuration and size combination to accurately reflect the true action of the valves.

At the same time, I would be surprised if Daniel has not done this type of testing in the development of their valves so you might try contacting them to see if they have the data you require.

As a general question, why you are concerned about the flow vs. lift profile on this control valve. The unit is designed to be self actuated to control its flow rate based upon the selected controlling parameter(s), i.e, discharge backpressure or other customer chosen input.