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Brinnelling

Discussion in 'Technical Discussion' started by SeaEng, Jan 13, 2011.

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  1. SeaEng, Jan 13, 2011
    #1
    SeaEng

    SeaEng New Member

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    Hi,

    Just wondering if anyone knows how one would reduce the effect of Brinnelling caused by bearings (Roller Bearing) in a turbocharger?

    Thanks,
  2. K1W1, Jan 13, 2011
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    K1W1

    K1W1 Senior Member

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    Hi,

    Is the brinelling caused by the bearings in the turbo or are the turbo bearings the ones showing the signs of brinelling?
  3. SeaEng, Jan 13, 2011
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    SeaEng

    SeaEng New Member

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    Hi Kiwi,

    The brinnelling is caused by the boats naturally vibration, ie within the E/R and effects the bearings, ie, the indentation of the bearing race.

    The reason I am asking is that I found this in a past Marine Diesel exam paper and am curious as to how one would reduce this effect.

    Cheers
  4. K1W1, Jan 13, 2011
    #4
    K1W1

    K1W1 Senior Member

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    Hi,

    You could the load off the balls while the engine is stationary but should really address the source of the vibration.

    This can be done by changing main engine speed, varying ballast quantities and positions in the ship or by having the equipment manufacturers visit and attend to their troublesome units.
  5. SeaEng, Jan 13, 2011
    #5
    SeaEng

    SeaEng New Member

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    Thanks for that. I just find it a strange question set by the SQA with regards to TurboCharger bearings, as like you said, one should really address the source of the vibration and eliminate.

    thanks for the reply though
    cheers
  6. K1W1, Jan 13, 2011
    #6
    K1W1

    K1W1 Senior Member

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    Hi,

    Another way if you ever encounter this problem that will not normally be on yachts is to keep the turbo rotating.
  7. Marmot, Jan 13, 2011
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    Marmot

    Marmot Senior Member

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    Since it's an exam question, they might be looking for a response that mentions operating the engine so as to prevent "barking" or continuous operation near the edge of the surge point.

    Surging can create very large torque swings that can beat up the bearings pretty badly.
  8. Silver Lining, Jan 14, 2011
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    Silver Lining

    Silver Lining Member

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    If you are refering to Brinneling and not false Brinneling, then I would think the answer is a bearing race with a higher Brinnel hardness, since Brinneling generally occurs under static loads that exceed a materials elastic limit. Perhaps there is too much end play in the turbo, but since the turbo is not rotating under static conditions how is there vibration, maybe the gensets? If the brinneling is caused by vibration in a static bearing, then in the case of a turbo with small static loads but very high dynamic loads, it would again seem to be either bearing play or hardness.
  9. SeaEng, Jan 17, 2011
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    SeaEng

    SeaEng New Member

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    Thanks Silver Lining!
  10. K1W1, Jan 17, 2011
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    K1W1

    K1W1 Senior Member

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    Hi,

    I would keep my answers to exam questions as simple as possible especially those asked during an Oral Examination unless you want to find yourself doing Extra Chiefs a lot sooner than you planned.
  11. SeaEng, Jan 17, 2011
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    SeaEng

    SeaEng New Member

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    Agreed Kiwi. I think that given the replies have got above, I would say that the best bet would be to identify that you have an understanding of the effect of Brinnelling and then perhaps ilke Silver Lining said, advise that ensure that you select a bearing with Brinnel hardness and ensure that you have the correct size bearing to eliminate the effects of Brinnelling.
  12. Marmot, Jan 18, 2011
    #12
    Marmot

    Marmot Senior Member

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    Is this for an oral exam or a PEng test on turbocharger design?

    If it is for a marine engineer's exam, please keep in mind that the object of the question is to determine if you know how to manage an existing piece of machinery, not design a new one. It is not the engineer's decision on what kind or size of bearings to use as replacements for the turbocharger on an engine under his care.

    There are not that many trees in this forest.
  13. SeaEng, Jan 20, 2011
    #13
    SeaEng

    SeaEng New Member

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    well, thanks for all your comments. Having looked further into this, I have found some further information that suggests making use of resilient mountings which may incorporate spring damping or some sorts for the ball and roller bearings.

    I think without getting carried away with an answer , the above would be a correct.
  14. Fishy, Jan 21, 2011
    #14
    Fishy

    Fishy New Member

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    Thanks from one of , im sure , many lurkers , you guys are educating the rest of us that dont even know what we dont know:D