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.
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.
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RE: Implications of inverting the rotation of a Steam Turbine
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
Johnny Pellin
RE: Implications of inverting the rotation of a Steam Turbine
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
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
Johnny Pellin