Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Gas Turbine Inlet Flow with Static Pressure Taps

Gas Turbine Inlet Flow with Static Pressure Taps

Gas Turbine Inlet Flow with Static Pressure Taps

Good day,
I've trying to figure out something that I would like to request your help with. For a converging nozzle in a single inlet and single exit control volume; if you know the static pressure at the inlet to the nozzle and the outlet to the nozzle, how would you go about determining the mass flow. Assume ideal air conditions non compressible flow. Is there a simple equation for that? I'm trying to figure out how one would be able to instrument such nozzle to determine if there are obstructions downstream of the nozzle.

Thank you!

RE: Gas Turbine Inlet Flow with Static Pressure Taps

I think you would need to pick up a textebook on gas turbine design. I suspect the blade open area was designed for optimium efficiency, and that occurs when the relative velocity between the incoming gases and the blades is equal to 50% soundspeed. If you know the gas's inlet T and molecular weight, you can calculate the soundspeed then calculate the required open area and bladed speed for optimum efficiency.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

RE: Gas Turbine Inlet Flow with Static Pressure Taps

I think you could look at the basics of how a flow element works. There is a relationship between variation of pressures between pressure taps, the flow element geometry and mass flow (or volume flow).

You need to check this reference and look at the nozzle type of geometry for flow element:
Flow Measurement Engineering Handbook, by Richard W. Miller.

Otherwise, my guess is that if there is an obstruction downstream, it would create a back pressure which can be detected by reduction of flow thru the nozzle from a departing value. But if your pressure upstream increases at the same time, say because you can control an equipment that does this, then the flow would go up again even in presence of the obstruction. Would that make sense?

RE: Gas Turbine Inlet Flow with Static Pressure Taps

Sorry I just had a second thought while reading the subject...
Are you referring to the main inlet of turbine or just doing a flow measurement on a certain pipe equipped with a nozzle?

RE: Gas Turbine Inlet Flow with Static Pressure Taps

A read of page 10-13 with equation 10-20 for flow through venturi nozzles in Perry Chem Engg Handbook 7th edition may help.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


eBook - Functional Prototyping Using Metal 3D Printing
Functional prototypes are a key step in product development – they give engineers a chance to test new ideas and designs while also revealing how the product will stand up to real-world use. And when it comes to functional prototypes, 3D printing is rewriting the rules of what’s possible. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close