×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Implications of inverting the rotation of a Steam Turbine

Implications of inverting the rotation of a Steam Turbine

Implications of inverting the rotation of a Steam Turbine

(OP)
Hi, I´m a senior year Mechanical Engineering Student, I´m writing this post because I need some advice from engineers with experience in tribology and lubrication for my internship project. Summarizing, the subject of the project is about studying the impact of inverting rotation of an axial Steam Turbine model 503T (two stages, non-condensing) manufactured by Dresser-Rand and how this change will impact the performance and life of the mechanical components of the turbine.

At this moment the turbine is at the workshop and repair duties are being made to allow the turbine to rotate counter wise. However I´m doubtful about whether the hydrodynamic bearings of the turbine ( sleeve bearings, tilting pad type) will be lubricated properly during operation if they were not replaced, lubrication of bearings is by oil rings by the way.

I´ve read a technical paper about oil ring lubrication for sleeves bearings which mentions that lubrication is not independent of rotational direction and therefore bearings should be engineered for a specific direction, say clockwise or counterclockwise (there are exceptions).

I will really appreciate your comments to know whether lubrication of sleeve bearings is independent of rotation of direction, thanks in advance.




RE: Implications of inverting the rotation of a Steam Turbine

That is a single stage turbine. It has two wheels, but only one set of nozzles. We have reversed a little single stage turbine like this before. It can be done. The bearings only need to be changed if they are rotationally specific. A tilt pad radial bearing with center pivots is probably not directionally specific. If it has embedded temperature probes, they will need to be moved to the trailing edge of the pads. Does it use the same bearing (same part number) on both ends? If so, the bearings are suitable for reverse rotation since they are installed for opposite rotation on each end of the turbine now.

I suspect you have already identified the other changes needed:

New rotor to reverse the blading.
New reversing ring.
New nozzle ring.
New hydraulic governor (if equipped) or reverse the rotation of the existing governor if it is a type that can be reversed (Woodward TG).

Johnny Pellin

RE: Implications of inverting the rotation of a Steam Turbine

We have several turbines of that model. I have never seen one with tilt-pad radial bearings. And, if I had one with tilt-pad radial bearings, I would expect it to be lubricated with a pressurized, circulating lube oil system, not oil rings. Are you sure those are tilt-pad bearings lubricated only with oil rings?

Johnny Pellin

RE: Implications of inverting the rotation of a Steam Turbine

(OP)
Thanks fo your quick answer, yes I already figured out most the changes that you pointed out, the governor is a Woodward TG 611-17 so it can work in reverse direction (the proceure can be found in the manual). Regarding the sleeve bearings the same model number is mounted on both ends.

I have never worked with turbomachinery before (I´m an undergrad) so I want to ask you about that "reversing ring" since I don´t know it´s function and where to find it.

About the bearings, I was told that those bearings were tilt pad type but after checking the technical documentation again I can´t confirm this to be true (it´s not specified). I have a picture (see below) which shows the radial bearings, it might help:

RE: Implications of inverting the rotation of a Steam Turbine

Those bearings appear to be plain cylindrical sleeve bearings. They are not tilt-pad since they have no moving parts. If both bearings use the same part number, but are installed facing opposite directions, then they are suitable for either rotation. The picture makes it look like the bearings are the same (oil feed groove, anti-rotation pin, etc.) I would recommend contacting Dresser-Rand and asking them to confirm that those bearings are suitable for reverse rotation.

The reversing ring is a segment of stationary blades that is positioned between the two sets of rotating blades. The steam strikes the first row of blades and is deflected off at an angle. The stationary reversing ring, redirects the flow of steam back in the original direction so it strikes the second wheel at the ideal angle. Because this flow of steam is only occurring in an area in line with the steam nozzles, it is only in an arc near the bottom of the turbine. I tried to find a good picture of a set of reversing buckets, but couldn't.

Johnny Pellin

RE: Implications of inverting the rotation of a Steam Turbine

The reversing ring is in the bottom of the turbine case in line with the nozzle ring.

Johnny Pellin

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


Resources

White Paper - Strategies to Secure Connected Cars with Firewalls
White-hat hackers have demonstrated gaining remote access to dashboard functions and transmissions of connected vehicles. That makes a firewall a vital component of a multilayered approach to vehicle security as well as overall vehicle safety and reliability. Learn strategies to secure with firewalls. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - What is Generative Design and Why Do You Need It?
Engineers are being asked to produce more sophisticated designs under a perfect storm of complexity, cost, and change management pressures. Generative design empowers automotive design teams to navigate this storm by employing automation, data re-use and synchronization, and framing design in the context of a full vehicle platform. Download Now
eBook - Simulation-Driven Design with SOLIDWORKS
Simulation-driven design can reduce the time and cost of product development. In this engineering.com eBook, we’ll explore how SOLIDWORKS users can access simulation-driven design through the SOLIDWORKS Simulation suite of analysis tools. 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