Because of the huge variety of process conditions in terms of the fluid, pressure, flowrate, noise, control valve type of operation.

These look more like plug and cage type to me and high pressure choke valve design.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Yeah, these trims are plug and cage type and used for noise control also.

And they are used for high-pressure globe valve design. But why there is such variety in trims? And how one can know about which trim to select?

errr did you not read my first paragraph??

Well in general the user doesn't select the trim, they leave that to the valve supplier to whom they have sent a data sheet with their process requirements on and they rely on that companies decades of experience and control valve design to choose the correct trim that is going to do the job for along time and not either function or wear out in three months.

Trying to learn this sort of stuff from the internet is not normally the best approach....

I can see you're new to the industry, but please do some basic research before asking rather vague open questions with no apparent practical purpose.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Thank you LittleInch for the reply,

Okay, I understand. Yes, I am aware that the user doesn't select the trim design but the valve company does.

If I want to understand the selection process/criteria of the company, how can I learn this stuff?
Can you please suggest to me about where or how I can get knowledge regarding this stuff?

Thanks

your best bet is to do some searching on large company sites for things like

emerson control valve handbook is one I have downloaded,

Fisher have one I think as does Masoneilan and I'm sue a few other vendors offer such downloads.

There are also various industry websites, magazines and similar which can offer advice and general guides.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Okay. I will surely check out different magazines and websites for the cage designs.

Thank you for the help

Have a great day!!

For your reading pleasure:
https://kentintrol.com/wp-content/uploads/2016/11/...

Walt

Thank you, Walt.

I will definitely have look at it. It looks quite informative. Thank you very much for sharing!!

Prasad