This is my first post.
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I have a question regarding the 'special' characteristic of a hydraulic turbine. I work at a Pumped Storage plant in Cape Town, South Africa. I am having difficulty explaining to the mechanical engineers why there is a drop in pressure around the Francis turbine when the wicket gates are opened further to allow more water flow through the turbine.
Could any of you help me with this explanation?
In terms of the transfer functions of the hydraulic turbine model, when using the initial value theorem, it shows the power output decreases. The power then increases at a rate determined by the water time constant. I said there is a pressure drop but I think that the power drop is due to the pressure dropping. Is this correct?
Your help will be greatly appreciated.
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