Can an enclosed Pelton Turbine be used as a pump, perhaps through the centrifugal forces created in a enclosed Pelton Turbine when it rotates at speed?

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The water striking out of the buckets of a Pelton turbine is left with diminished energy but because the wheel is rotating continuously at high speeds due to very high velocity water jet then, is there any possibility of development of centrifugal forces that may lift up the water through a discharge pipe connected to the casing of the turbine which actually happens in centrifugal pumps?

Is there any possibility of this, even if this happens to a small degree? Can create centrifugal forces lift the water, so it functions as pump and turbine simultaneously?

Please suggest any means by which we could pump the discharged water via a pelton turbine.

  • Thanks: that's very helpful. I've updated your question with the extra information you've provided. – EnergyNumbers Dec 6 '13 at 11:02
  • any update to the question are welcomed but the theme should remain the same. – user33715 Dec 6 '13 at 14:08
  • Do you have an old pelton that you want to put to a new use? What's the background of the question? – mart Dec 6 '13 at 14:16
  • No, that's not the reason. I have a project on this. – user33715 Dec 6 '13 at 14:34
  • You would be better off lifting the turbine so you can have the outlet higher up. – Móż Dec 8 '13 at 5:25

See one way of using pumps as turbines is an old hat in some applications.
In fact, some go the other way and use a centrifugal pump as a turbine, there's some guidance (that may be dated) available on that subject.

Using a pelton turbine as a pump, on the other, I'm highly sceptical about that: The shape of the turbine is so that flow from one side would not reach the other sides. So I'd expect a load of water that's moved around at low rpm, cavitation at high rpm, and a bad performance overall. Not however that this is more an answer coming from intuition than from actual knowledge.

Edit to add
If you look at the impeller of a centrifugal pump, you see this spiral form - the fluid is gradually acceleated as it travels outward. With the pelton turbine, you have a smooth inner section and then the blades. I'd expect turbulence, and thus energy loss, at the interface.

  • right...me too have similar intuition but could we manage to have that with some additional design arrangements. – user33715 Dec 6 '13 at 14:33
  • but if you redesign it to the point where it works better than "paddles that throw water", you will probably have done more work than would be required to build a proper pump. – Móż Dec 6 '13 at 21:42
  • I'd say the first design rearrangement (that you probably thought of too) would be to ensure that the flow to the pump is from both sides of impeller. – mart Dec 6 '13 at 21:51
  • But maybe you try to understand (maybe ask in an engieering forum, or even phone KSB and talk to their sales engineer) why the typical way to do it is "pump as turbine" and not the other way round. – mart Dec 6 '13 at 21:54

Many turbines can be switched round to be pumps of some kind. But to try to do both at the same time, is going to hit efficiency badly. There is no free energy - it's all got to come from somewhere, and it's all got to end up somewhere else: the same quantity, just in different forms. So if you're turning some of the incoming water's kinetic energy into increased gravitational potential, there will be much less work generated by the turbine that is available for other purposes.

And equipment tends to be most efficient, when it's used for the purpose that it's designed for. So, one option might be to use some of the energy captured by the turbine to drive a separate pump: one that is designed for the operation you intend of it.

  • thanks for the much dedicated answer, being a new user I couldn't give you +1 for this....But It would be great even if the turbine generates less power when performing as pump and turbine, because in the case I'm dealing with, we can't generate power with mono function of turbine. I'm just urging to suggest the means by which we could do both the functions at the same time or periodically. And for that matter, perhaps development of centrifugal forces could work... – user33715 Dec 9 '13 at 11:37
  • Rather than reduce the efficiency of the turbine by using some of its energy as a pump, why not just take some of its mechanical energy (or electrical if you're driving a generator) to run a proper pump? – Johnny Dec 9 '13 at 23:14

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