high velocity 1

[nabilou77]

Hi dear members,
i'm asking if there is a material (metallic, non metallic or hybrid) which can survive to a sea water velocity of 120 m/s ?
thanks for your comments

 

[EdStainless]

Sure there are, many high strength, corrosion resistant Ni alloys would do OK, and Co alloys even better.
Look at Ultimet from Haynes.

You could try a 6%Mo superaustenitic stainless, but I have only seen data to about 150 ft/sec.

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Plymouth Tube

 

[nabilou77]

thank you for the response, but as you said, the maximum velocity that i found is around 40-45 m/s (131-147 ft/s).

 

[EdStainless]

At this flow I presume that there will be cavitation. Look at Co alloys.
I have used them as chokes in high flow situations, but I doubt that I ever went much over 200 ft/sec.
Is this a choke? If so then look at Silicon carbide ceramics.

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Plymouth Tube

 

[nabilou77]

In fact, my question is regarding a pumped storage hydroelectricity project where the velocity reach such values. so we are starting to think what could be the materials candidates for pipes with diameters about 7 meters. may be we should think about high strenght metals with ceramic coating ?
thanks

 

[EdStainless]

There have to be some units wrong here.
If you had any length of this pipe you would get very little flow.
At this velocity 300m of pipe would have a 30bar pressure drop, that is 1,000 ft of head loss.

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Plymouth Tube

 

[nabilou77]

excuse me, 7 m is the tunnel diameter. the pipe diameter will be about 4-5 m according to the project manager. they want to produce 250 MW as energy which corresopnd to high pumping capacity.

 

[EdStainless]

The numbers don't jive.
This is too small of a passage.
Your flow is in the 5GW range, way off.

Double check the math.

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Plymouth Tube